JP6977358B2 - Liquid injection device, color measurement method and drive method of liquid injection device - Google Patents

Description

The present invention relates to a liquid injection device, a color measurement method, and a method for driving the liquid injection device, which comprises a liquid injection head for injecting a liquid into a medium and a color measuring unit for measuring the color of the liquid landing on the medium. The present invention relates to a type recording device, a color measuring method, and a driving method of an inkjet recording device.

In an inkjet recording device, which is a typical example of a liquid injection device, the reproducibility of printed colors varies depending on the characteristics of the printing medium and the characteristics of the recording head that ejects ink. Therefore, by printing the patch of the standard color on the inkjet recording device and measuring the color of the patch by the color measuring device provided in the recording device, the color measurement value of the patch and the table in the standard color space of the standard color are displayed. Generates color conversion information based on the difference from the color value. Then, it has been proposed to perform printing with high color reproducibility by converting the input image data based on the color conversion information generated from the colorimetric value and executing printing (for example, Patent Document). See 1).

Japanese Unexamined Patent Publication No. 2013-228370

At this time, since the color reproducibility is different for each different type of medium, it is necessary to measure the color for each different type of medium. However, since different types of media have variations in thickness, there is a problem that color measurement cannot be performed with high accuracy.

Therefore, as in Patent Document 1, when the color measurement result is corrected from the position of the color measurement device with respect to the medium after the color measurement, there is a problem that the accuracy of the color measurement result is lowered.

It should be noted that such a problem exists not only in the inkjet recording device but also in the liquid injection device that injects a liquid other than ink.

In view of such circumstances, it is an object of the present invention to provide a liquid injection device, a color measurement method, and a method for driving a liquid injection device, which are equipped with a color measurement device capable of performing highly accurate color measurement.

Aspects of the present invention for solving the above problems include a liquid injection head that injects liquid into a medium, a light projecting unit that irradiates the surface to be measured of the medium with light, and the medium that emits light emitted from the light projecting unit. It has a light receiving unit that receives the reflected light reflected by the surface to be measured, and the color measuring unit that measures the color of the surface to be measured coincides with the central axis of the light beam emitted from the projected surface. The color measurement data of the surface to be measured, which is a change unit that changes the reflection position of the light to be reflected on the medium, and the light receiving unit receives light at the reflection position changed in the change unit and the color measurement unit measures the color. The liquid injection device is characterized by comprising a control unit for setting the reflection position at which the color measurement data having the highest brightness is measured at the color measurement position.
In such an embodiment, since the color measurement can be performed with the reflection position having the highest brightness as the color measurement position, highly accurate color measurement can be performed.

Here, the control unit controls the change unit to measure the color when the light receiving unit receives the light reflected on the surface of the support member that supports the surface of the medium opposite to the surface to be measured. It is preferable to set the position where the brightness of the color measurement data measured by the unit is the highest as the reference position, and acquire the thickness of the medium based on the reference position and the color measurement position. According to this, since the thickness of the medium can be measured by using the color measuring unit, a sensor or the like for measuring the thickness of the medium becomes unnecessary, the cost can be reduced, and the size can be reduced. be able to.

Further, the control unit is based on the thickness of the medium and the color measurement result of the non-landing region where the liquid of the medium measured by the color measurement unit at the color measurement position is not landed. It is preferable to specify the medium. According to this, by specifying the medium based on the thickness of the medium and the color measurement result of the non-landing region of the medium, the optimum print setting for the medium can be set and the print quality can be improved.

Further, it is preferable that the changing unit changes the distance between the color measuring unit and the medium in the normal direction of the surface to be measured of the medium. According to this, the reflection position can be easily changed by changing the distance between the color measuring unit and the medium in the normal direction of the surface to be measured of the medium.

Further, in another aspect of the present invention, a liquid injection head that injects liquid into the medium, a light projecting unit that irradiates the surface to be measured of the medium with light, and light emitted from the light projecting unit of the medium. It has a light receiving unit that receives the reflected light reflected by the surface to be measured, and coincides with the central axis of the light beam emitted from the light projecting unit and the color measuring unit that measures the color of the surface to be measured. The color measurement data having the highest brightness is measured among the color measurement data measured by the color measurement unit at the change unit that changes the reflection position of the light on the surface to be measured and the color measurement unit at the reflection position changed in the change unit. The liquid injection device is characterized by comprising a control unit for setting a color measurement position based on a difference between the colored reflection position and a preset reference position.
In such an embodiment, since the color measurement can be performed with the reflection position having the highest brightness as the color measurement position, highly accurate color measurement can be performed. Further, even if the thickness of the medium varies, the color can be measured with high accuracy by setting the color measurement position based on the difference between the highest reflection position and the preset reference position.

Further, the changed part changes the distance between the light emitting part and the light receiving part in the surface direction of the measured surface, or the changed part irradiates the normal line of the measured surface with the light emitting part. It is preferable to change the angle or the light receiving angle of the light receiving portion. According to this, the reflection position can be easily changed by changing the distance between the light emitting portion and the light receiving portion in the surface direction of the surface to be measured, or by changing the irradiation angle or the light receiving angle.

Further, it is preferable that the color measuring unit is provided on the upstream side of the liquid injection head in the transport direction of the medium. According to this, it is possible to suppress the mist generated by injecting the liquid from the liquid injection head from adhering to the color measuring portion.

Further, it is preferable that the liquid injection head and the color measuring unit are mounted on a carriage provided so as to be movable in a transport direction of the medium and a direction orthogonal to the measured surface. According to this, the color measurement unit can measure the color over the entire surface of the medium. Further, by mounting the color measuring unit and the liquid injection head on the same carriage, the number of parts can be reduced, the cost can be reduced, and the size can be reduced.

Further, the control unit has color conversion information based on the color measurement value of the surface to be measured measured by the color measurement unit at the color measurement position or the color measurement value of the patch printed on the surface to be measured. It is preferable to color-convert the print data by. According to this, highly accurate color conversion information can be acquired based on the color measurement value of the measured surface or the color measurement value of the patch printed on the measured surface, and printing with improved color reproducibility can be performed. realizable.

Further, in another aspect of the present invention, a light projecting unit that irradiates the surface to be measured of the medium with light and a reflected light obtained by reflecting the light emitted from the light projecting unit on the surface to be measured of the medium are received. It has a light receiving unit and a color measuring unit that measures the color of the surface to be measured, and changes the reflection position of light on the medium that coincides with the central axis of the light beam emitted from the light projecting unit. The reflected light is received by the light receiving unit, the color of the surface to be measured is measured, and the brightness of the surface to be measured is measured by the light receiving unit and the color measuring unit among the changed reflection positions. The color measuring method is characterized in that the color is measured by the color measuring unit with the highest reflection position as the color measuring position.
In such an embodiment, since the color measurement can be performed with the reflection position having the highest brightness as the color measurement position, highly accurate color measurement can be performed.

Further, in another aspect of the present invention, a liquid injection head that injects a liquid into the medium, a light projecting unit that irradiates the surface to be measured of the medium with light, and a light projecting unit that is irradiated from the light projecting unit to measure the medium. It is a driving method of a liquid injection device including a light receiving unit that receives light reflected by a surface and a color measuring unit that measures the surface to be measured of the medium, wherein the light emitting unit and the light receiving unit are provided. And the medium are set to the first relative position, the light emitted from the light projecting unit and reflected by the measured surface of the medium is received by the light receiving unit, and the brightness of the measured surface of the medium is measured. The first color measurement value including the indicated value is measured, the light emitting unit, the light receiving unit, and the medium are set to a second relative position different from the first relative position, and the light emitting unit is used. The light received by the light receiving portion of the medium and reflected by the surface to be measured is received by the light receiving unit, a second color measurement value indicating the brightness of the surface to be measured of the medium is measured, and the first color measurement value is measured. When the lightness of the light is higher than the lightness of the second color measurement value, the first relative position is set to the color measurement position, and the color of the medium measured at the color measurement position or on the medium is displayed. A method of driving a liquid injection device, which comprises color-converting print data by color conversion information based on a color measurement value of a printed patch.
In such an embodiment, high-precision color measurement can be performed by performing color measurement with the first relative position for measuring the color of the first color measurement value having a higher brightness than the second color measurement value as the color measurement position. .. Further, since the color measurement may be performed at at least two relative positions of the first relative position and the second relative position, the color measurement time can be shortened.

Here, the light projecting unit, the light receiving unit, and the medium are included, and the relative positions of the light emitting unit, the light receiving unit, and the medium include the first relative position and the second relative position, respectively. The light is set to a plurality of relative positions at three or more different locations, and at each of the plurality of relative positions, the light emitted from the light projecting section and reflected by the measured surface of the medium is received by the light receiving section, and the medium is received. It is preferable to measure the color measurement value indicating the brightness of the surface to be measured. According to this, by performing color measurement at a plurality of relative positions, the distance between the central axis of the luminous flux emitted from the light projecting section and the optical axis of the light receiving optical system of the light receiving section is shortened as much as possible, and high brightness is achieved. The color can be measured with, and the color measurement accuracy can be improved.

Further, it is preferable that the brightness of the first color measurement value is the highest brightness among the brightness of the color measurement values measured at the plurality of relative positions. According to this, the distance between the central axis of the luminous flux emitted from the light projecting section and the optical axis of the light receiving optical system of the light receiving section can be shortened as much as possible to measure the color with high brightness, and the color measurement accuracy can be improved. Can be enhanced.

Further, in another aspect of the present invention, a liquid injection head that injects a liquid into the medium, a light projecting unit that irradiates the surface to be measured of the medium with light, and a light projecting unit that is irradiated from the light projecting unit to measure the medium. It is a driving method of a liquid injection device including a light receiving unit that receives light reflected by a surface, a color measuring unit that measures a color of the surface to be measured of the medium, and the light emitting unit and the light receiving unit. And the medium are set to the first relative position, the light emitted from the light projecting section and reflected by the measured surface of the medium is received by the light receiving section, and the brightness of the measured surface of the medium is measured. The first colorimetric value including the indicated value is measured, the light emitting part, the light receiving part, and the medium are set to a second relative position different from the first relative position, and the light emitting part is used. The light received by the light receiving unit is received by the light receiving unit, and the second color measurement value indicating the brightness of the measurement surface of the medium is measured, and the first color measurement value is measured. When the brightness of is higher than the brightness of the second colorimetric value, the light projecting unit, the light receiving unit, and the medium are based on the difference between the first relative position and the preset reference relative position. The relative position with is set to the color measurement position, and the print data is color-converted by the color conversion information based on the color of the medium measured at the color measurement position or the color measurement value of the patch printed on the medium. It is a method of driving a liquid injection device, which is characterized by the above.
In such an embodiment, when the first colorimetric value at the first relative position has a higher brightness than the second colorimetric value at the second relative position, the difference between the first relative position and the reference relative position Based on this, it is possible to perform color measurement by setting the light projecting unit, the light receiving unit, and the medium to the color measurement position that has the same color measurement conditions as the reference relative position, so that even if the thickness of the medium varies, At the color measurement position, the color measurement condition, particularly the height of the color measurement unit from the surface to be measured, can always be the same condition, and high-precision color measurement can be performed.

Here, the first relative position and the second relative position may differ in the distance between the light emitting portion and the light receiving portion in a direction intersecting the normal direction of the measured surface of the medium. preferable. According to this, the reflection position can be easily changed by changing the distance between the light emitting portion and the light receiving portion in the direction intersecting the normal direction of the surface to be measured.

When the brightness of the first colorimetric value is higher than the brightness of the second colorimetric value, the distance between the light projecting portion and the light receiving portion at the first relative position and the advance. It is preferable to move the color measuring unit in the normal direction of the surface to be measured by a distance calculated from the difference between the distance between the light emitting unit and the light receiving unit at the set reference relative position. According to this, even if the thickness of the medium varies, at the color measurement position, the height from the surface to be measured of the color measurement unit can always be measured under the same conditions, and high-precision color measurement can be performed. It can be carried out.

Further, it is preferable that the angle of the central axis of the light beam emitted from the light projecting portion with respect to the normal of the surface to be measured is different between the first relative position and the second relative position. According to this, the reflection position can be easily changed by changing the irradiation angle or the light receiving angle.

Further, when the brightness of the first color measurement value is higher than the brightness of the second color measurement value, the light is irradiated from the light projecting portion with respect to the normal of the surface to be measured at the first relative position. Only the distance calculated from the difference between the angle of the central axis of the light flux to be measured and the angle of the central axis of the light beam emitted from the light projecting portion with respect to the normal of the surface to be measured at the preset reference relative position. It is preferable to move the color measuring unit in the normal direction of the surface to be measured. According to this, even if the thickness of the medium varies, at the color measurement position, the height from the surface to be measured of the color measurement unit can always be measured under the same conditions, and high-precision color measurement can be performed. It can be carried out.

Further, the light projecting portion, the light receiving portion, and the support member supporting the surface of the medium opposite to the surface to be measured are set at a third relative position, and the support member is irradiated from the light projecting portion. The light reflected by the support surface supporting the medium is received by the light receiving unit, and a third color measurement value including a value indicating the brightness of the support surface of the support member is measured, and the light projecting unit and the above are measured. The light receiving portion and the support member are set to a fourth relative position different from the third relative position, and the light received from the light projecting portion and reflected on the support surface of the support member is received by the light receiving portion. Then, a fourth colorimetric value indicating the brightness of the support surface of the support member is measured, and when the brightness of the third colorimetric value is higher than the brightness of the fourth colorimetric value, It is preferable to set the third relative position as a reference position and detect the thickness of the medium from the difference between the color measurement position and the reference position. According to this, by detecting the thickness of the medium by the color measuring unit, another sensor or the like for measuring the thickness of the medium is not required separately, the cost can be reduced, and the sensor is arranged. Space is not required and miniaturization can be achieved. Further, by acquiring the thickness of the medium, the paper gap, which is the distance between the liquid injection head and the medium, can be controlled with high accuracy.

It is a schematic diagram of the recording apparatus which concerns on Embodiment 1. FIG. It is a main part plan view of the recording apparatus which concerns on Embodiment 1. FIG. It is a side view of the main part of the recording apparatus which concerns on Embodiment 1. FIG. It is a main part perspective view which shows the changed part of the recording apparatus which concerns on Embodiment 1. FIG. It is a block diagram which shows the electric structure of the recording apparatus which concerns on Embodiment 1. FIG. It is a block diagram which shows the function realization part of the control processing part which concerns on Embodiment 1. FIG. It is a side view of the main part of the recording apparatus which concerns on Embodiment 1. FIG. It is a side view of the main part of the recording apparatus which concerns on Embodiment 1. FIG. It is a side view of the main part of the recording apparatus which concerns on Embodiment 1. FIG. It is a graph which shows the relationship between the reflection position and the brightness which concerns on Embodiment 1. FIG. It is a flowchart which shows the color measurement method which concerns on Embodiment 1. It is a block diagram which shows the function realization part of the control processing part which concerns on Embodiment 2. It is a side view of the main part of the recording apparatus which concerns on Embodiment 2. FIG. It is a side view of the main part of the recording apparatus which concerns on Embodiment 2. FIG. It is a side view of the main part of the recording apparatus which concerns on Embodiment 3. FIG. It is a side view of the main part of the recording apparatus which concerns on Embodiment 3. FIG. It is a side view of the main part of the recording apparatus which concerns on Embodiment 3. FIG. It is a side view of the main part of the recording apparatus which concerns on Embodiment 4. FIG. It is a side view of the main part of the recording apparatus which concerns on Embodiment 4. FIG. It is a side view of the main part of the recording apparatus which concerns on Embodiment 4. FIG. It is a flowchart which shows the driving method which concerns on Embodiment 5. It is a side view of the main part of the recording apparatus which concerns on Embodiment 5. It is a side view of the main part of the recording apparatus which concerns on Embodiment 5. It is a figure explaining the illuminance distribution which concerns on Embodiment 5. It is a figure explaining the illuminance distribution which concerns on Embodiment 5. It is a figure explaining the illuminance distribution which concerns on Embodiment 5. It is a figure explaining the illuminance distribution which concerns on Embodiment 5. It is a figure explaining the illuminance distribution which concerns on Embodiment 5. It is a figure explaining the illuminance distribution which concerns on Embodiment 5. It is a flowchart which shows the driving method which concerns on Embodiment 6. It is a side view of the main part of the recording apparatus which concerns on Embodiment 6. It is a side view of the main part of the recording apparatus which concerns on Embodiment 6. It is a flowchart which shows the driving method which concerns on Embodiment 7. It is a side view of the main part of the recording apparatus which concerns on Embodiment 7. It is a side view of the main part of the recording apparatus which concerns on Embodiment 7. It is a side view of the main part of the recording apparatus which concerns on Embodiment 7. It is a side view of the main part of the recording apparatus which concerns on Embodiment 7. It is a flowchart which shows the driving method which concerns on Embodiment 8. It is a side view of the main part of the recording apparatus which concerns on Embodiment 8. It is a side view of the main part of the recording apparatus which concerns on Embodiment 8. It is a side view of the main part of the recording apparatus which concerns on Embodiment 8. It is a side view of the main part of the recording apparatus which concerns on Embodiment 8.

Hereinafter, the present invention will be described in detail based on the embodiments.
(Embodiment 1)
FIG. 1 is a diagram showing a schematic configuration of an inkjet recording device which is an example of the liquid injection device according to the first embodiment of the present invention, and FIG. 2 is a plan view showing a main part of the inkjet recording device. FIG. 3 is a side view showing a main part of the inkjet recording device.

As shown in the figure, the inkjet recording device I includes an inkjet recording head 1 (hereinafter, also referred to as a recording head 1) that ejects ink as a liquid. An ink cartridge 2 constituting an ink supply means is detachably provided on the recording head 1. Such a recording head 1 is mounted on the carriage 3.

The carriage 3 on which the recording head 1 is mounted is provided on the carriage shaft 5 attached to the apparatus main body 4 so as to be movable in the axial direction. Then, the driving force of the drive motor 6 is transmitted to the carriage 3 via a plurality of gears and a timing belt 7 (not shown), so that the carriage 3 equipped with the recording head 1 is moved along the carriage shaft 5.

On the other hand, the apparatus main body 4 is provided with a support member 8 that supports a surface on which ink droplets of the recording sheet 100, which is a medium, lands, a so-called printing surface and a surface opposite to the surface to be measured 101.

Further, the apparatus main body 4 is provided with a transport means for transporting the recording sheet 100 onto the support member 8 and also transporting the recording sheet 100 printed or color-measured on the support member 8 from the support member 8. ing. In the present embodiment, as the transport means, the first transport means 9a and the second transport means 9b are provided at positions sandwiching the support member 8. The direction in which the first transport means 9a and the second transport means 9b are separated from each other is the transport direction of the recording sheet 100, which is referred to as the first direction X, and the upstream side of the transport direction of the recording sheet 100 is X1 and downstream. The side is referred to as X2.

Specifically, the first transport means 9a is provided on the upstream side of the recording sheet 100 in the transport direction, that is, on the X1 side of the first direction X with respect to the recording head 1. The recording sheet 100 is conveyed by the first conveying means 9a to a position facing the recording head 1, that is, on the support member 8. Further, the second transport means 9b is provided on the downstream side of the recording sheet 100 in the transport direction, that is, on the X2 side of the first direction X, with respect to the recording head 1. The recording sheet 100 on the support member 8 is conveyed by the second conveying means 9b toward the X2 side of the first direction X. In the present embodiment, the first transport means 9a and the second transport means 9b are composed of transport rollers. The first transport means 9a and the second transport means 9b are not limited to the transport rollers, and may be belts, drums, or the like.

In the present embodiment, as described above, the moving direction of the carriage 3 along the carriage axis 5 with respect to the first direction X, which is the transport direction of the recording sheet 100, is referred to as a second direction Y, and the carriage axis is referred to as a second direction Y. The one end side of 5 is referred to as Y1 and the other end side is referred to as Y2. By the way, in the carriage 3, the Y2 side, which is one end side of the carriage shaft 5, is the home position, and the Y2 side is not particularly shown, but is a cleaning means for cleaning the ejection surface on which the ink droplets of the recording head 1 are ejected. Is provided. Further, the direction intersecting both the first direction X and the second direction Y is referred to as a third direction Z in the present embodiment, and the recording head 1 side is referred to as Z1 and the recording head 1 with respect to the recording sheet 100. On the other hand, the recording sheet 100 side is referred to as Z2. In the present embodiment, the relationship in each direction (X, Y, Z) is orthogonal, but the arrangement relationship of each configuration is not necessarily limited to being orthogonal.

In such an inkjet recording apparatus I, the recording sheet 100 is conveyed to the recording head 1 in the first direction X, and the carriage 3 is moved to the recording sheet 100 in the second direction Y while being moved to the recording head. By ejecting ink droplets from the nozzle of No. 1, so-called printing is executed in which the ink is landed on substantially the entire surface of the measured surface 101 of the recording sheet 100.

Further, the inkjet recording apparatus I is provided with a color measuring unit 10 for measuring the color of the measured surface 101 of the recording sheet 100 in a non-contact manner. In the present embodiment, the color measuring unit 10 is mounted on the carriage 3 together with the recording head 1. Therefore, the recording sheet 100 is conveyed to the carriage 3 in the first direction X, and the carriage 3 is moved in the second direction Y with respect to the recording sheet 100 while the color is measured by the color measuring unit 10. The color can be measured over substantially the entire surface of the measured surface 101 of the recording sheet 100.

As shown in FIG. 3, such a color measuring unit 10 includes a light emitting unit 20 and a light receiving unit 30. Then, the light emitted from the light projecting unit 20 is reflected by the measured surface 101 of the recording sheet 100, the reflected reflected light is received by the light receiving unit 30, and based on the signal output from the light receiving unit 30, the reflected light is received. The chromaticity of the surface to be measured 101 is analyzed and measured.

The light projecting unit 20 includes a light source 21 that emits light, and a light source optical system 22 (only one is shown in the figure) composed of a plurality of lenses.

The light source 21 irradiates light distributed over at least a wavelength range to be measured, and is not particularly limited, but preferably has a uniform distribution of light intensity with respect to a wavelength. Examples of such a light source 21 include a white LED (Light Emitting Diode).

The light source optical system 22 includes a collimating lens that emits the light of the light source 21 as a substantially parallel light beam, and the light emitted from the light source 21 is irradiated as parallel light by the light source optical system 22.

Further, in the present embodiment, the light projecting unit 20 is arranged so that the central axis of the light flux of the irradiated parallel light is tilted 45 degrees toward the light receiving unit 30 side with respect to the third direction Z. The optical axis of the light projecting unit 20 itself or the optical system 22 for a light source may be tilted at 45 degrees with respect to the third direction Z, and the parallel light emitted along the third direction Z may be a prism. It may be tilted at 45 degrees with respect to the third direction Z by a reflector or the like.

As long as the central axis of the light beam emitted to the measured surface 101 is 45 degrees with respect to the normal line of the measured surface 101, the detailed configuration of the light projecting unit 20 is not particularly limited. The optical system 22 for a light source may be provided with optical elements such as a lens, a prism, and a reflecting surface.

The light receiving unit 30 includes a light receiving optical system 31 composed of a plurality of lenses and filters, and a light receiving element 32.

The light receiving optical system 31 includes a wavelength variable interference filter, and the light receiving element disperses only the light of a predetermined wavelength among the reflected light reflected by the measured surface 101 by the wavelength variable interference filter. Let 32 receive light.

The optical axis of the light receiving optical system 31 coincides with the normal direction of the surface to be measured 101. The optical axis of the light receiving unit 30 itself or the light receiving optical system 31 may be configured to coincide with the normal direction of the measured surface 101, and the light reflected from the measured surface 101 in the normal direction may be configured. The detailed configuration of the light receiving unit 30 is not particularly limited as long as it is incident on the light receiving element 32. The light receiving optical system 31 may be provided with optical elements such as a lens, a prism, and a reflecting surface.

The light receiving element 32 is composed of a plurality of photoelectric conversion elements, and generates an electric signal according to the amount of light received.

Such a color measuring unit 10 is provided so as to be movable in the second direction Y. In the present embodiment, the color measuring unit 10 can be moved in the second direction Y by mounting the color measuring unit 10 on the carriage 3 on which the recording head 1 is mounted. In this way, by mounting the color measuring unit 10 on the carriage 3 that moves the recording head 1 in the second direction Y, the color measuring unit 10 is moved in the second direction Y separately from the carriage 3 for the recording head 1. The carriage for the color measuring unit 10 that moves to is not required. Therefore, the carriage for the color measuring unit 10 and the driving means for driving the carriage for the color measuring unit 10 are not required, and the inkjet recording device I can be miniaturized and the cost can be reduced. Of course, the color measuring unit 10 may not be provided on the carriage 3 on which the recording head 1 is mounted, but may be mounted on the carriage for the color measuring unit 10.

Further, the color measuring unit 10 is preferably provided on either one side of the first direction X, which is the transport direction of the recording sheet 100, in the carriage 3, and is provided on the X1 side, which is the upstream side of the transport direction of the recording sheet 100. Is preferable. As a result, the mist generated by the ink ejected from the recording head 1 is unlikely to adhere to the color measuring unit 10. Incidentally, since the recording head 1 ejects ink droplets while moving in the second direction Y as described above, the mist generated by the ink ejected from the recording head 1 is in the second direction of the recording head 1. It flows downstream in the moving direction of Y. Since the recording head 1 reciprocates in the second direction Y, a large amount of mist flows out to both the Y1 side and the Y2 side of the second direction Y of the recording head. Therefore, if the color measuring unit 10 is provided on any one side of the second direction Y of the recording head 1, mist easily adheres to the color measuring unit 10, and the adhering mist does not allow normal color measurement. In addition, the color measurement unit 10 needs to be cleaned, resulting in poor color measurement and time-consuming color measurement. Further, when the recording sheet 100 is transported in the first direction X, an air flow is generated from X1 upstream in the transport direction toward X2 downstream in the transport direction. Therefore, a large amount of mist generated by the ink ejected from the recording head 1 flows out to the X2 side, which is the downstream side, so that the color measuring unit 10 is located upstream of the recording head 1 in the transport direction of the recording sheet 100, that is, , It is preferable to provide it on the X1 side of the first direction X. In this way, by providing the color measuring unit 10 on the upstream side of the recording sheet 100 in the transport direction, that is, on the X1 side of the first direction X, the color measuring unit 10 is less likely to adhere to the color measuring unit 10. Color measurement failure due to the adhering mist is unlikely to occur, and cleaning of the adhering mist is unnecessary or the interval until cleaning can be lengthened to shorten the color measurement time.

Further, the inkjet recording apparatus I is provided with a changing unit 40 (see FIG. 4) for changing the reflection position of the central axis of the light flux emitted from the light projecting unit 20 on the measured surface 101 of the recording sheet 100. ing. In the present embodiment, the changing unit 40 changes the distance between the color measuring unit 10 and the recording sheet 100 in the third direction Z, which is the normal direction of the measured surface 101 of the recording sheet 100. Specifically, the changing unit 40 moves the carriage 3 on which the color measuring unit 10 is mounted in the third direction Z with respect to the support member 8 so as to be on the recording sheet 100 supported on the support member 8. The reflection position of the reflected light emitted and reflected from the light projecting unit 20 of the above is changed. That is, since the light projecting angle of the light projecting unit 20 and the light receiving angle of the light receiving unit 30 of the present embodiment are fixed, the light projecting unit 20 and the light receiving unit 30 are moved closer to and away from the surface to be measured 101. The reflected position of the reflected light emitted and reflected from the light projecting unit 20 on the surface to be measured 101 can be changed.

The reflected position of the reflected light emitted and reflected from the light projecting unit 20 on the measured surface 101 means that the light beam corresponding to the central axis of the light flux emitted from the light projecting unit 20 is reflected on the measured surface 101. It is the position. Further, the change in the reflection position of the reflected light emitted and reflected from the light projecting unit 20 on the measured surface 101 means that the light beam corresponding to the central axis of the light flux emitted from the light projecting unit 20 is on the measured surface 101. It is to change the position of reflection. On the other hand, the position where the light beam corresponding to the central axis of the light beam emitted from the light projecting unit 20 is reflected on the surface to be measured 101 does not change, and the irradiation area due to the light beam from the light projecting unit 20 changes. It is not included in the change of the reflection position of the reflected light emitted and reflected from the light projecting unit 20 on the 101.

Hereinafter, the “reflection position of the reflected light” means a position where the light beam corresponding to the central axis of the light beam emitted from the light projecting unit 20 is reflected on the surface to be measured 101.

Here, the modified portion 40 of the present embodiment will be further described with reference to FIG. Note that FIG. 4 is a perspective view of a main part of the inkjet recording device showing the change unit 40.

As shown in FIG. 4, the changing unit 40 is configured such that the rotation of the output shaft (not shown) of the elevating drive motor is transmitted to the carriage shaft 5 by the transmission gear train 5a. A composite gear having detection blades called a flag (not shown) is provided in the middle of the transmission gear train 5a, and the rotation angle of the carriage shaft 5 can be changed by detecting the flag by a rotation angle detecting means such as a rotary encoder. Be controlled. The carriage shaft 5 is in sliding contact with a bearing portion (not shown) provided on the carriage 3 to guide the reciprocating movement of the carriage 3, and rotary shaft portions 5b are provided at both ends. A transmission gear 5c is provided on the rotary shaft portion 5b on one end side of the carriage shaft 5 so as to be rotatable integrally with the carriage shaft 5 with the central axis of the carriage shaft 5 as the rotation center. Then, the rotation of the elevating drive motor is transmitted to the transmission gear 5c via the transmission gear train 5a. Further, shift cams 5d having the same shape are provided at both ends of the carriage shaft 5 so as to be rotatable integrally with the carriage shaft 5 so that the reference cam positions are the same. Further, a cam follower 5e is provided below each shift cam 5d, and the carriage shaft 5 moves in parallel in the third direction Z due to the rotation of the carriage shaft 5, and the carriage is interlocked with the carriage shaft 5 that moves in parallel. 3 is configured to be separated from and close to the support member 8. The height of the carriage 3 from the support member 8 can be converted from the rotation angle of the carriage shaft 5 by the rotary encoder described above. Then, the changing unit 40 can adjust the height of the color measuring unit 10 with respect to the recording sheet 100 in the third direction Z by adjusting the height of the carriage 3 with respect to the support member 8 in the third direction Z. The reflected position of the reflected light on the surface to be measured 101 can be changed.

Further, since the change unit 40 can move the carriage 3 in the third direction Z with respect to the support member 8, the distance between the recording head 1 and the recording sheet 100, that is, the so-called paper gap (PG) is also adjusted. Can be done. That is, the changing unit 40 that changes the position of the color measuring unit 10 in the third direction Z with respect to the recording sheet 100 can also be used to adjust the distance between the recording head 1 and the recording sheet 100. Of course, when the color measuring unit 10 is not mounted on the carriage 3 on which the recording head 1 is mounted but is mounted on the carriage for the color measuring unit 10, the moving unit that moves the carriage 3 on which the recording head 1 is mounted is moved. And the above-mentioned change unit 40 may be provided separately.

Here, the control device 200 of such an inkjet recording device I will be further described with reference to FIG. Note that FIG. 5 is a block diagram showing an electrical configuration of the inkjet recording device of the present embodiment.

As shown in FIG. 5, the inkjet recording device I includes a control unit 210, a printing mechanism 220, and a color measuring mechanism 230 of the present embodiment.

The control unit 210 is an element that controls the entire inkjet recording device I, and is provided in the control device 200 provided in the inkjet recording device I in the present embodiment (see FIG. 1).

Further, the control unit 210 includes a control processing unit 211 including a CPU and the like, a storage unit 212, a drive signal generation unit 213, an external I / F (interface) 214, and an internal I / F 215. Print data (also referred to as image data) indicating an image to be printed on the recording sheet 100 is transmitted from an external device 250 such as a host computer to an external I / F 214, and a printing mechanism 220 is connected to the internal I / F 215.

The printing mechanism 220 is an element that records an image on the recording sheet 100 under the control of the control unit 210, and includes the recording head 1, the first transport means 9a and the second transport means 9b, and a motor (not shown) that drives them. The paper feed mechanism 221 and the like, the carriage mechanism 222 of the drive motor 6 and the timing belt 7, and the change unit 40 are provided.

The storage unit 212 includes a ROM for recording a control program and the like, and a RAM for temporarily recording various data necessary for printing an image. The control processing unit 211 comprehensively controls each element of the inkjet recording device I by executing the control program recorded in the storage unit 212. Further, although the control processing unit 211 will be described in detail later, the external control processing unit 211 is based on a color measurement value obtained by measuring the color of a patch (not shown) formed on the measured surface 101 of the recording sheet 100 by the color measurement unit 10. Color conversion information for color conversion of print data transmitted from the device 250 to the external I / F 214 is generated, and the print data is color-converted based on the color conversion information.

The control processing unit 211 indicates, for each nozzle, the injection / non-injection of ink droplets from each nozzle of the recording head 1 for the print data color-converted based on the color conversion information, for example, a clock signal CLK. , Latch signal LAT, change signal CH, pixel data SI, setting data SP, etc. are converted and transmitted to the recording head 1 via the internal I / F 215. Further, the drive signal generation unit 213 generates a drive signal (COM) and transmits it to the recording head 1 via the internal I / F 215. That is, injection data such as head control data and drive signals are transmitted to the recording head 1 via the internal I / F 215 which is a transmission unit.

Further, the control processing unit 211 generates a movement control signal of the paper feed mechanism 221 and the carriage mechanism 222 from the print data color-converted based on the color conversion information, and the paper feed mechanism 221 and the carriage via the internal I / F 215. It transmits to the mechanism 222 and controls the paper feed mechanism 221 and the carriage mechanism 222.

Further, the control processing unit 211 generates a paper gap control signal from the data related to the paper gap received from the external device 250 via the external I / F 214, transmits the paper gap control signal to the changing unit 40 via the internal I / F 215, and transmits the paper gap. The change unit 40 is controlled so as to adjust.

The color measuring mechanism 230 is an element that measures the color of the measured surface 101 of the recording sheet 100 under the control of the control processing unit 211, and is the color measuring unit 10, the first transport means 9a, and the second transport means 9b. It has a paper feed mechanism 221 such as a motor (not shown) for driving the drive motor 6, a carriage mechanism 222 such as a drive motor 6 and a timing belt 7, and a change unit 40.

The control processing unit 211 controls the paper feed mechanism 221 and the carriage mechanism 222, and the color measuring unit 10 mounted on the carriage 3 is placed in the first direction X and the second direction Y on the measured surface 101 of the recording sheet 100. Place in the desired position.

Further, the control processing unit 211 controls the color measuring unit 10 to irradiate the light from the light emitting unit 20 and receive the light reflected by the light receiving unit 30 at a desired position on the surface to be measured 101.

Further, the control processing unit 211 changes the reflection position of the light corresponding to the central axis of the light flux emitted from the light projecting unit 20 on the measured surface 101 while performing the color measurement by the color measuring unit 10. The change unit 40 is controlled.

Here, a specific function realization unit that measures the color of the control processing unit 211 will be further described with reference to FIG. Note that FIG. 6 is a block diagram showing a function realization unit of the control processing unit 211.

As shown in FIG. 6, the control processing unit 211 includes a color measurement unit control unit 300 that controls the color measurement unit 10, a color measurement processing unit 301, a change unit control unit 302 that controls the change unit 40, and a brightness determination. A unit 303 and a color measurement position setting unit 304 are provided.

The color measuring unit control unit 300 controls the color measuring unit 10 to irradiate the light from the light projecting unit 20 and to receive the light reflected by the light receiving unit 30 on the surface to be measured 101.

The color measurement processing unit 301 digitizes a color in a color system from an electric signal received from the color measurement unit 10. In the present embodiment, the color measurement processing unit 301 digitizes, for example, in the L * a * b * color system.

The change unit control unit 302 controls the change unit 40 to change the reflection position of the reflected light on the measured surface 101 of the recording sheet 100. In the present embodiment, as described above, the carriage 3 on which the color measuring unit 10 is mounted is moved by the changing unit 40 in the third direction Z with respect to the support member 8, and the recording sheet is supported on the support member 8. The reflection position of the reflected light on 100 is changed.

In such a control processing unit 211, the color measuring unit control unit 300 and the changing unit control unit 302 control the color measuring unit 10 and the changing unit 40 so that the reflected light reflected on the surface to be measured 101 is at a different position. Color measurement is performed multiple times, and the color measurement result is generated as color measurement data quantified by the color system for each color measurement. The color measurement data is recorded in the storage unit 212 in association with the reflection position data indicating the reflection position of the reflected light on the measured surface 101 changed by the change unit 40. In the present embodiment, the value indicating the height of the carriage 3 (height of the color measuring unit 10) in the third direction Z from the reference position is used as the reflection position data, and the reflection position data at the time of color measurement (third). The color measurement data (distance from the reference position in the direction Z to the carriage 3 (color measurement unit 10) at the time of color measurement) is associated with the color measurement data and recorded in the storage unit 212.

By the way, since the height of the carriage 3 in the third direction Z is changed by the changing portion 40 moving the carriage shaft 5, the reflection position data is not the height of the carriage 3 described above, but the carriage shaft 5. (The distance from the reference position in the third direction Z to the carriage shaft 5). Further, the height of the carriage 3 in the third direction Z from the reference position is the height of the light receiving surface of the light receiving element 32 in the light receiving unit 30 of the color measuring unit 10 mounted on the carriage 3 (third direction). It may be the height of the injection surface of the recording head 1 (distance from the reference position in the third direction Z to the injection surface) or the like (distance from the reference position in Z to the light receiving surface). Further, the height of the carriage 3 or the like from the reference position in the third direction Z can be converted from the rotation angle of the carriage shaft 5 by the rotation angle detecting means (not shown) provided in the changing portion 40. Of course, instead of calculating the height of the carriage 3 or the like in the third direction Z from the rotation angle of the carriage shaft 5, the rotation angle may be used directly as the reflection position data indicating the height of the carriage 3 or the like. That is, the reflection position data is particularly long as it is data that can specify the reflection position of the reflected light corresponding to the central axis of the light flux emitted from the light projection unit 20 changed by the change unit 40 on the measured surface 101 of the recording sheet 100. Not limited.

Further, the reference for defining the height of the carriage 3 which is the reflection position data is one point in the range where the carriage shaft 5 can move in the third direction Z, for example, the lowermost end on the Z2 side and the uppermost end on the Z1 side. Or it may be the center, or it may be one point in the rotatable range of the carriage shaft 5, for example, the rotation start end, the rotation end, and the rotation center, and further, when the carriage 3 and the carriage shaft 5 are moved relatively. It may be a non-moving portion, for example, a part of the apparatus main body 4, the surface of the support member 8, or the surface to be measured 101.

Further, the color measurement at the position where the reflected light reflected on the measured surface 101 is different can be performed by, for example, the resolution of the rotation angle detecting means for detecting the rotation angle of the carriage shaft 5 of the changing unit 40 in the minimum unit. ..

Then, the brightness determination unit 303 determines the color measurement data having the highest brightness of the reflected light in the diffuse reflection from the result of the color measurement by the color measurement unit 10. For example, when the color measurement data is quantified in the L * a * b * color system, the color measurement data having the highest L * value is selected. This makes it possible to select the color measurement data with the highest brightness.

Here, the light emitted from the light projecting unit 20 is diffusely reflected by the surface to be measured 101, and the diffusely reflected reflected light is received by the light receiving unit 30.

In the illuminance distribution of the light beam emitted from the light projecting unit 20 on the measured surface 101, the illuminance of the portion corresponding to the central axis of the light beam is high, and the illuminance of the portion corresponding to the outer periphery of the light beam is low. When the color of the surface to be measured 101 irradiated with the light flux from the light projecting unit 20 is measured, high brightness is measured in the region where the light in the center of the light beam from the light projecting unit 20 is reflected, and the light is projected. The lower the brightness is measured in the region where the light farther from the central portion of the light flux from the light portion 20 is reflected.

In the example shown in FIGS. 7 to 9, the height of the third direction Z from the measured surface 101 of the color measuring unit 10 which is the reflection position data is measured from the measured surface 101 in the third direction Z to the recording head 1. The distance to the injection surface was used. Therefore, as shown in FIG. 7, at the height h1 of the third direction Z from the measured surface 101 of the color measuring unit 10, the central axis of the light flux from the light emitting unit 20 and the light receiving optical system of the light receiving unit 30. When the optical axis of 31 coincides with the measured surface 101, the light receiving unit 30 receives the reflected light from the region with high illuminance on the measured surface 101, so that the height is h1 as shown in FIG. The brightness measured by the light receiving unit 30 is the highest. That is, the relative positional relationship between the light projecting unit 20, the light receiving unit 30, and the measured surface 101 such that the central axis of the light flux from the light projecting unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 coincide with each other. If there is, the brightness measured by the light receiving unit 30 becomes high.

On the other hand, as shown in FIG. 8, when the height (distance) h2 of the color measuring unit 10 from the measured surface 101 is lower than the height h1, it becomes the central axis of the light flux from the light projecting unit 20. The optical axis of the light receiving optical system 31 of the light receiving unit 30 does not match on the measured surface 101, and the light receiving unit 30 receives the reflected light from the low illuminance region on the measured surface 101. As shown in the above, the brightness measured by the light receiving unit 30 is lower in the case of the height h2 than in the case of the height h1. That is, in the relative positional relationship between the light projecting unit 20, the light receiving unit 30, and the measured surface 101 such that the central axis of the light flux from the light projecting unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 do not match. , The brightness measured by the light receiving unit 30 becomes low.

Similarly, as shown in FIG. 9, when the height (distance) h3 of the color measuring unit 10 from the measured surface 101 is higher (longer) than the height h1, the central axis of the light flux from the light projecting unit 20 And the optical axis of the light receiving optical system 31 of the light receiving unit 30 do not match on the measured surface 101, and the light receiving unit 30 receives the reflected light from the low illuminance region on the measured surface 101. As shown in No. 10, the brightness measured by the light receiving unit 30 becomes low. That is, if the relative positional relationship between the light projecting unit 20, the light receiving unit 30, and the surface to be measured 101 is such that the light beam that coincides with the central axis of the light beam from the light projecting unit 20 does not enter the light receiving unit 30, the light receiving unit 30 The brightness measured by is low.

That is, in the present embodiment, since the central axis of the light flux emitted from the light projecting unit 20 and the angle of the optical axis of the light receiving optical system 31 of the light receiving unit 30 with respect to the measured surface 101 are fixed, the light projecting unit 20 By moving the light receiving unit 30 closer to and further from the surface to be measured 101, the reflected position of the reflected light on the recording sheet 100 of the luminous flux from the light projecting unit 20 can be changed. Therefore, the brightness determination unit 303 coincides with the central axis of the light flux emitted from the light projecting unit 20 by determining the color measurement data having the highest brightness from the plurality of color measurement data measured by the color measurement unit 10. It is determined whether or not the light to be applied matches the light receiving optical system 31 of the light receiving unit 30 on the surface to be measured 101. In the present embodiment, the reflection position of the light beam emitted from the light projecting unit 20 on the measured surface 101 is the height h1 of the color measuring unit 10 from the measured surface 101 by moving the carriage 3 in the third direction Z. Since it is changed by adjusting ~ h3, the brightness determination unit 303 determines the color measurement data having the highest brightness, and the reflection indicating the height from the reference of the carriage 3 associated with the color measurement data. The position data, that is, the height h1 of the recording sheet 100 of the color measuring unit 10 from the measured surface 101 can be substantially specified.

The color measurement position setting unit 304 sets the reflection position data specified by the brightness determination unit 303 to determine the color measurement data having the highest brightness in the storage unit 212 as the color measurement position. Then, the color measurement on the recording sheet 100 is performed at the color measurement position set by the color measurement position setting unit 304. That is, once the color measurement position is set, the set color measurement position is not changed, that is, the carriage 3 on which the color measurement unit 10 is mounted is not moved in the third direction Z by operating the change unit 40. The color measuring unit 10 measures colors at a plurality of points on the measured surface 101 of the recording sheet 100.

A color measuring method using such a color measuring unit 10 and a changing unit 40 will be described with reference to FIG. Note that FIG. 11 is a flowchart showing the color measurement method.

When the color measurement is started, the color measurement position setting mode is first set. Specifically, in step S1, color measurement is performed a plurality of times while changing the reflection position of the reflected light. That is, while the changing unit control unit 302 controls the changing unit 40 and changes the height of the color measuring unit 10 in the third direction Z from the measured surface 101, the color measuring unit control unit 300 controls the color measuring unit 300. Color measurement is performed by controlling 10. The color measurement processing unit 301 digitizes the measurement result of the color measurement unit 10 in a color system to generate color measurement data, and the color measurement data is associated with the reflection position data and stored in the storage unit 212. Next, in step S2, the brightness determination unit 303 determines the color measurement data having the highest brightness from the plurality of color measurement data. Next, in step S3, the color measurement position setting unit 304 sets the reflection position data associated with the color measurement data specified by the brightness determination unit 303 in the storage unit 212 as the color measurement position. After that, in step S4, at the measurement position set by the color measurement position setting unit 304, the color measurement unit control unit 300 performs color measurement at a plurality of points on the surface to be measured 101.

The color measurement position may be set for each recording sheet 100 in steps S1 to S3, but for example, when the recording sheets 100 of the same standard are used, steps S1 to S3 may not be performed. That is, when a recording sheet of the same standard as the recording sheet 100 in which the color measurement position is set is used, the thickness is the same, so that the optical axis of the reflected light is less likely to shift, and the color measurement position is substantially changed. It will be the same. Therefore, when using recording sheets of the same standard, by measuring colors using the same color measurement position, the process of setting the color measurement position becomes unnecessary, and the time required for color measurement can be shortened. can. Of course, even when a recording sheet having the same standard as the recording sheet 100 in which the color measurement position is set is used, the color measurement position may be reset by performing steps S1 to S4. As a result, even if there is an error in the thickness of the recording sheet of the same standard, the optimum color measurement position can be set.

As described above, in the present embodiment, the light receiving unit 40 is controlled to change the reflection position on the measured surface 101 of the recording sheet 100 of the light corresponding to the central axis of the light emitted from the light emitting unit 20. The reflection position having the highest brightness of the color measurement data obtained from the reflected light received by 30 is set as the color measurement position. Therefore, it is possible to measure the color of a patch (not shown) printed on the surface to be measured 101 at the reflection position having the highest brightness, so that the color measurement accuracy can be improved. By the way, when the color measurement of the patch is performed at the reflection position where the brightness is low, the color measurement accuracy is low, and the color reproducibility is lowered when the image data is color-converted by the color conversion information based on the color measurement value. In the present embodiment, by improving the color measurement accuracy, the image data can be color-converted by the color conversion information based on the highly accurate color measurement value, and the color reproducibility can be improved.

Further, the changing unit 40 of the present embodiment changes the reflection position by changing the distance between the color measuring unit 10 and the surface to be measured 101 in the third direction Z. In particular, in the present embodiment, the color measuring unit 10 is mounted on the carriage 3 on which the recording head 1 is mounted, and the carriage 3 is moved to the carriage 3 in the third direction Z with respect to the measured surface 101. The mounted color measuring unit 10 is moved in the third direction Z with respect to the surface to be measured 101. Therefore, the changing unit 40 can also serve as a mechanism for changing the distance between the recording head 1 and the recording sheet 100, that is, a so-called paper gap. Further, since the carriage 3 on which the recording head 1 is mounted is provided so as to be movable in the second direction Y, by mounting the color measuring unit 10 on the carriage 3, the color measuring unit 10 can be moved in the second direction Y. There is no need for a separate mechanism to move to. Therefore, a mechanism for individually moving the color measuring unit 10 and the recording head 1 in the second direction Y and the third direction Z becomes unnecessary, and the size can be reduced and the cost can be reduced. ..

In this embodiment, the recording head 1 and the color measuring unit 10 are mounted on the same carriage 3, and the distance between the recording head 1 and the recording sheet 100 is determined by the changing unit 40 that moves the carriage 3 in the third direction Z. , The distance between the color measuring unit 10 and the recording sheet 100 is changed, but the present invention is not particularly limited to this. For example, the recording head 1 and the color measuring unit 10 are mounted on the same carriage 3, and the head position changing unit for moving the recording head 1 in the third direction Z and the color measuring unit 10 in the third direction Z are mounted on the carriage 3. It is also possible to provide a change part to move to. Further, the recording head 1 and the color measuring unit 10 may be mounted on different carriages.

Further, in the present embodiment, the color measuring unit 10 is provided on the X1 side, which is the upstream side of the recording head 1, in the first direction X, which is the transport direction of the recording sheet 100. Therefore, it is difficult for mist to adhere to the color measuring unit 10, color measurement failure due to the adhered mist is unlikely to occur, cleaning of the adhered mist is unnecessary, or the interval until cleaning is lengthened to shorten the color measuring time. Can be done.

In the present embodiment, the color measuring unit 10 is provided on the X1 side of the recording head 1 in the carriage 3, but even when the color measuring unit 10 is not mounted on the carriage 3, the color measuring unit 10 is provided. By arranging the carriage on the X1 side of the recording head 1, it is possible to suppress the adhesion of mist.

(Embodiment 2)
FIG. 12 is a block diagram showing a function realization unit of the control processing unit 211 of the inkjet recording device which is an example of the liquid injection device according to the second embodiment of the present invention, and FIG. 13 is a side view illustrating a reference position. 14 is a side view illustrating the color measurement position. The same members as those in the above-described embodiment are designated by the same reference numerals, and duplicate description will be omitted.

In this embodiment, the thickness of the recording sheet 100 is measured by using the color measuring unit 10 and the changing unit 40. That is, the reflection position where the brightness of the reflected light reflected on the support member 8 in which the recording sheet 100 is not set is the highest is set as the reference position, and this reference position and the reflection on the recording sheet 100 are reflected. The thickness of the recording sheet 100 is calculated based on the color measurement position where the brightness of the reflected light is highest.

Specifically, as shown in FIG. 12, the control processing unit 211 further includes a reference position acquisition unit 305 and a medium thickness calculation unit 306 as a function realization unit.

The reference position acquisition unit 305 controls the color measurement unit 10 and the change unit 40 by the color measurement unit control unit 300 and the change unit control unit 302, and the light projection unit on the surface of the support member 8 to which the recording sheet 100 is not conveyed. The reflection position data having the highest brightness of the color measurement data obtained from the reflected light of the luminous flux emitted from 20 is acquired as a reference position.

Specifically, the reference position acquisition unit 305 controls the color measurement unit 10 by the color measurement unit control unit 300, reflects the light emitted from the light projecting unit 20 on the support member 8, and reflects the reflected light. Light is received by the light receiving unit 30. In this way, the color measurement processing unit 301 digitizes the electric signal received by the color measurement unit 10 in the color system to generate color measurement data.

Further, the reference position acquisition unit 305 controls the change unit 40 by the change unit control unit 302 to change the reflection position of the reflected light on the surface of the support member 8. In the present embodiment, as described above, the carriage 3 on which the color measuring unit 10 is mounted is moved by the changing unit 40 in the third direction Z with respect to the support member 8, and the reflected light is reflected on the support member 8. Change the position.

Further, the reference position acquisition unit 305 has a plurality of reference position acquisition units 305 at positions where the reflected light reflected by the support member 8 is different by causing the color measurement unit control unit 300 and the change unit control unit 302 to control the color measurement unit 10 and the change unit 40. The color is measured repeatedly, and the color measurement result is quantified in the color system for each color measurement and generated as color measurement data. The color measurement data is the reflection position of the reflected light on the support member 8 changed by the change unit 40, and in the present embodiment, the reflection position indicating the height in the third direction Z from the reference position of the carriage 3. It is associated with the data and recorded in the storage unit 212.

By the way, since the height of the carriage 3 in the third direction Z is changed by the changing portion 40 moving the carriage shaft 5, the reflection position data is not the height of the carriage 3 described above, but the carriage shaft 5. Height (distance from the reference position in the third direction Z to the carriage shaft 5). Further, the height of the carriage 3 in the third direction Z from the reference position is the height of the light receiving surface of the light receiving element 32 in the light receiving unit 30 of the color measuring unit 10 mounted on the carriage 3 (third direction). It may be the height of the injection surface of the recording head 1 (distance from the reference position in the third direction Z to the injection surface) or the like (distance from the reference position in Z to the light receiving surface). Further, the height of the carriage 3 or the like from the reference position in the third direction Z can be converted from the rotation angle of the carriage shaft 5 by the rotation angle detecting means (not shown) provided in the changing portion 40. Of course, instead of calculating the height of the carriage 3 or the like in the third direction Z from the rotation angle of the carriage shaft 5, the rotation angle may be used directly as the reflection position data indicating the height of the carriage 3 or the like. That is, the reflection position data is particularly long as it is data that can specify the reflection position of the reflected light corresponding to the central axis of the light flux emitted from the light projection unit 20 changed by the change unit 40 on the measured surface 101 of the recording sheet 100. Not limited.

Further, the reference for defining the height of the carriage 3 as the reflection position data is as the lowermost end on the Z2 side, the uppermost end on the Z1 side, or the center in the range in which the carriage shaft 5 can move in the third direction Z. It may be a rotation start end, a rotation end, or a rotation center in a rotatable range of the carriage shaft 5, and further, a portion that does not move relatively when the carriage 3 and the carriage shaft 5 are moved, for example, a device main body 4. It may be a part or the surface of the support member 8. In the present embodiment, as shown in FIG. 13, the surface of the support member 8 in the third direction Z, which is an index of the height of the color measuring unit 10 from the support member 8 in the third direction Z, as the reflection position data. To the injection surface of the recording head 1.

Then, the brightness determination unit 303 determines the color measurement data having the highest brightness of the reflected light in the diffuse reflection from the result of the color measurement by the color measurement unit 10. For example, when the color measurement data is quantified in the L * a * b * color system, the color measurement data having the highest L * value is selected. This makes it possible to select the color measurement data with the highest brightness.

Then, the reference position acquisition unit 305 sets the reflection position data associated with the color measurement data having the highest brightness determined by the brightness determination unit 303 in the storage unit 212 as a reference position. In the present embodiment, as shown in FIG. 13, Z0, which is the height from the surface of the support member 8 to the color measuring unit 10 in the third direction Z, and the reference position Z0 are set.

Further, similarly to the above-described first embodiment, the color measurement unit control unit 300, the change unit control unit 302, and the color measurement position setting unit 304 are reflected by the measured surface 101 of the recording sheet 100 installed on the support member 8. The measurement position where the brightness of the color measurement data due to the reflected light is the highest is detected, and this color measurement position is set in the storage unit 212. In the present embodiment, as shown in FIG. 14, the reflection position data to be the color measurement position is the color measurement position of Zm, which is the height from the surface of the support member 8 of the color measurement unit 10 in the third direction Z. It was set to Zm.

The medium thickness calculation unit 306 has a reference position Z0 at which the brightness of the color measurement data obtained from the reflected light of the support member 8 acquired by the reference position acquisition unit 305 is highest, and a recording set by the color measurement position setting unit 304. The thickness of the recording sheet 100 in the third direction Z is calculated based on the color measurement position Zm at which the brightness of the color measurement data obtained from the reflected light on the measured surface 101 of the sheet 100 is highest. That is, the thickness of the recording sheet 100 mounted on the support member 8 can be calculated by subtracting the color measurement position Zm from the reference position Z0 (Zm-Z0).

The height Zm from the surface of the support member 8 to the color measuring unit 10 is set as the measurement position, but the support member at the reference position where the brightness of the color measurement data obtained from the reflected light of the support member 8 is the highest. Since the height Z0 from 8 to the color measuring unit 10 does not change, the reference position Z0 (from the support member 8) is used as the reflection position data associated with the color measurement data reflected by the measured surface 101 of the recording sheet 100 and measured. It may be the amount of displacement of the color measuring unit 10 from the position at the height Zo). As a result, the reflection position data associated with the color measurement data having the highest brightness of the recording sheet 100 can be directly acquired as the thickness of the recording sheet 100.

As described above, in the present embodiment, the control unit 210 controls the change unit 40, and the light receiving unit 30 receives the light reflected on the surface of the support member 8 that supports the side opposite to the measured surface 101 of the recording sheet 100. The distance from the position of the color measuring unit 10 where the brightness is highest when light is received to the surface of the support member 8 is set as the reference position, and based on the reference position and the color measurement position of the measured surface 101 of the recording sheet 100. , The thickness of the recording sheet 100 was acquired. Therefore, a sensor or the like for measuring the thickness of the recording sheet 100 is not required separately, the cost can be reduced, and the space for arranging the sensor is not required, so that the size can be reduced. Further, by acquiring the thickness of the recording sheet 100, the paper gap, which is the distance between the recording sheet 100 and the recording head 1, can be controlled with high accuracy by the changing unit 40. Therefore, high-precision printing can be realized.

Further, in the present embodiment, the non-landing area where the ink droplets of the recording sheet 100 are not landed, that is, the non-printing area is measured to specify the paper white value, and the paper white value and the above-mentioned recording sheet are specified. The recording sheet 100 may be specified from the thickness of 100.

By the way, there are multiple types of recording sheets with different materials and thicknesses depending on the manufacturer and application. Therefore, the recording sheet can be specified based on the thickness of the recording sheet and the whiteness value of the paper measured by the color measuring unit 10. Then, by specifying the recording sheet, the optimum print setting can be set for the specified recording sheet. For example, the thickness and whiteness value of multiple types of recording sheets and the optimum print settings for each recording sheet are stored in advance as data, and the recording sheet is specified from the thickness and whiteness value of the recording sheet. , You can recall the best print settings for the specified recording sheet. Further, for example, the paper white value and thickness measured by the color measuring unit 10 in the past and the print setting set by the user when printing on the recording sheet are stored, and the past from the paper white value and thickness. When the same recording sheet as the color-measured and printed recording sheet is detected, the print settings set in the past may be recalled.

The recording sheet has different color reproducibility, ink absorbency, susceptibility to kinking due to ink impact, drying time, etc., depending on the type of material, thickness, and the like. Therefore, by specifying the recording sheet, color reproduction based on the ratio of a plurality of element colors used by the inkjet recording apparatus I, for example, cyan (C), magenta (M), yellow (Y), and black (K). It is possible to set the properties, the weight of ink droplets (driving amount), the paper gap (PG), the moving speed of the carriage 3, the paper feeding speed, and the like to be optimal for the recording sheet. Incidentally, the color reproducibility may be corrected based on the result of color measurement by the color measuring unit 10 after being called by the print setting.

After specifying the recording sheet 100, it is not necessary to automatically set the optimum print settings for the specified recording sheet 100. For example, if it is detected that the recording sheet specified from the thickness and the whiteness value is different from the recording sheet used last time, the user may be warned to reset the print setting. This also suppresses printing on different types of recording sheets with the same print settings, and suppresses the occurrence of printing defects.

As described above, the control unit 210 is the color measurement result of the thickness of the recording sheet 100 acquired by the color measurement unit 10 and the non-landing region where the ink of the recording sheet 100 measured by the color measurement unit 10 is not landed. By specifying the recording sheet 100 based on the paper white value, it is possible to set the optimum printing settings for the recording sheet 100 and suppress the occurrence of printing defects.

(Embodiment 3)
15 to 17 are side views of a main part of an inkjet recording device which is an example of the liquid injection device according to the third embodiment of the present invention. The same members as those in the above-described embodiment are designated by the same reference numerals, and duplicate description will be omitted.

As shown in FIG. 15, the changing unit 40 of the present embodiment changes the distance between the light emitting unit 20 and the light receiving unit 30 in the plane direction of the surface to be measured 101. In the present embodiment, the changing unit 40 moves the light emitting unit 20 in the second direction Y with respect to the light receiving unit 30.

Specifically, the changing unit 40 is a projection unit that is fixed to the carriage 3 and holds the projection unit 20 so as to be movable in the second direction Y, and a projection unit that moves the projection unit holding unit 41. The optical unit drive unit 42 is provided.

The light projecting unit driving unit 42 is not particularly limited as long as the light emitting unit holding unit 41 can be moved in the second direction Y with respect to the carriage 3, and for example, a motor, an electromagnet, or the like can be used. In the present embodiment, as the light projecting unit driving unit 42, a solenoid is used in which the tip of the plunger is brought into contact with the light projecting unit holding unit 41 so that the plunger can be moved in the second direction Y. Further, although not particularly shown, the changing unit 40 is provided with a moving distance detecting means such as a linear encoder capable of detecting the moving distance of the light projecting unit holding unit 41.

As shown in FIGS. 15 to 17, such a changing unit 40 changes the distance between the light emitting unit 20 and the light receiving unit 30 in the second direction Y, so that the measured surface 101 on the recording sheet 100 is measured. The reflection position of the reflected light on the top can be changed.

As shown in FIG. 15, when the height (distance from the measured surface 101 to the injection surface of the recording head 1) of the color measuring unit 10 from the measured surface 101 in the third direction Z is a reference value. At the distance w1 between the light emitting unit 20 and the light receiving unit 30, the central axis of the light flux from the light emitting unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 coincide with each other on the measured surface 101. The light receiving unit 30 can measure the color measurement data having the highest brightness. That is, the relative positional relationship between the light projecting unit 20, the light receiving unit 30, and the measured surface 101 as shown in FIG. 15 is a reference relative position at which the measured surface 101 can be accurately color-measured.

On the other hand, as shown in FIG. 16, when the height (distance) of the color measuring unit 10 from the measured surface 101 in the third direction Z is lower (shorter) than the example shown in FIG. 15, the light projecting unit At the distance w1 between the light receiving unit 20 and the light receiving unit 30, the central axis of the light flux from the light emitting unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 do not match on the measured surface 101, and the light receiving unit 30 Receives reflected light from a region of low illuminance on the surface to be measured 101, so that the example shown in FIG. 16 has a lower brightness measured by the light receiving unit 30 than the example shown in FIG. In the present embodiment, the changing unit control unit 302 controls the changing unit 40, and the color measuring unit control unit 300 measures the color while changing the distance between the light emitting unit 20 and the light receiving unit 30 in the second direction Y. The unit 10 is controlled to measure the color of the surface to be measured 101, and the color measurement processing unit 301 digitizes it in the color system to generate color measurement data. The color measurement data is associated with the reflection position data and is stored in the storage unit 212. Is remembered in. In the present embodiment, the distance between the light emitting unit 20 and the light receiving unit 30 in the second direction Y is the reflection position data. Next, the brightness determination unit 303 determines the color measurement data having the highest brightness from the plurality of color measurement data. In the case of the recording sheet 100 shown in FIG. 16, the distance between the light emitting unit 20 and the light receiving unit 30 is narrower than the distance w1, and the central axis of the light flux from the light emitting unit 20 and the light receiving optics of the light receiving unit 30. The optical axis of the system 31 coincides with the surface to be measured 101, and the light receiving unit 30 can measure the color measurement data having the highest brightness.

Similarly, as shown in FIG. 17, when the height (distance) of the color measuring unit 10 from the measured surface 101 in the third direction Z is higher (longer) than the example shown in FIG. 15, the light projecting unit 20 is used. At the distance w1 from the light receiving unit 30, the central axis of the light flux from the light emitting unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 do not match on the measured surface 101, and the light receiving unit 30 is covered. Since the reflected light from the low illuminance region on the measurement surface 101 is received, the brightness measured by the light receiving unit 30 is lower in the example shown in FIG. 17 than in the example shown in FIG. Even in such a case, the color measurement data having the highest brightness is determined from the plurality of color measurement data measured while changing the distance between the light emitting unit 20 and the light receiving unit 30 in the second direction Y as described above. do. In the case of the recording sheet 100 shown in FIG. 17, the distance between the light emitting unit 20 and the light receiving unit 30 is wider than the distance w1, and the central axis of the light flux from the light emitting unit 20 and the light receiving optics of the light receiving unit 30. The optical axis of the system 31 coincides with the surface to be measured 101, and the light receiving unit 30 can measure the color measurement data having the highest brightness.

As shown in FIG. 15, when it is determined that the brightness of the color measurement data at the reference interval w1 is high, the height of the color measurement unit 10 from the measured surface 101 in the third direction Z is the reference height. Therefore, it is not necessary to further move the color measuring unit 10, and the position becomes the color measuring position. However, as described above, when it is determined that the brightness of the color measurement data is high at an interval different from the reference interval w1, the color measurement data determined to have high brightness from the reference interval w1 is used. By calculating the difference between the current height of the third direction Z from the measured surface 101 of the color measuring unit 10 and the reference height from the amount of displacement up to the intervals w2 and w3, which are the associated reflection position data. 16 and 17, the color measuring unit 10 can be moved from the current height from the measured surface 101 to the reference height. Before performing color measurement to generate color conversion information, the height of the color measuring unit 10 from the surface to be measured 101 is set as the reference height, and the distance between the light emitting unit 20 and the light receiving unit 30 is used as the reference distance. By changing to the interval w1, the distance between the light emitting unit 20 and the light receiving unit 30 at the reference height of the color measuring unit 10 from the surface to be measured 101 also in the recording sheet 100 shown in FIGS. Is set to the interval w1 which is a reference position, and the central axis of the light flux emitted from the light projecting unit 20 can be aligned with the optical axis of the light receiving optical system 31 of the light receiving unit 30 on the surface to be measured 101.

That is, even if the thickness of the recording sheet 100 varies as shown in FIGS. 15 to 17, the height of the color measuring unit 10 in the third direction Z from the measured surface 101 is always the same reference height. The central axis of the luminous flux from the light emitting unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 are recorded on the recording sheet 100 at the same reference distance w1 between the light emitting unit 20 and the light receiving unit 30. Since the color can be measured at the highest brightness in combination with the above, it is possible to suppress the variation in the measurement conditions and suppress the variation in the brightness, and it is possible to perform high-precision color measurement. That is, since the height of the color measuring unit 10 shown in FIG. 16 from the measured surface 101 is lower than the reference height of FIG. 15, the distance between the light emitting unit 20 and the light receiving unit 30 is changed to change the distance between the light emitting unit 20 and the light receiving unit 30 to be measured. Even if the central axis of the luminous flux emitted from the light projecting unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 are aligned with each other, the height of the color measuring unit 10 from the measured surface 101 remains low. When the color is measured up to, the brightness measured is higher than when the color is measured at the reference height. Similarly, since the height of the color measuring unit 10 shown in FIG. 17 from the measured surface 101 is higher than the reference height shown in FIG. 15, the distance between the light emitting unit 20 and the light receiving unit 30 is changed to be measured. Even if the central axis of the light beam emitted from the light projecting unit 20 on the surface 101 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 are aligned with each other, the height of the color measuring unit 10 from the measured surface 101 is still high. If the color is measured while it is still high, the brightness measured will be lower than when the color is measured at the reference height. Therefore, the difference between the current height of the color measuring unit 10 from the measured surface 101 and the reference height is calculated based on the amount of displacement from the interval w1 to the intervals w2 and w3, and the color measuring unit 10 is set to the reference height. By moving to and setting the distance between the light emitting unit 20 and the light receiving unit 30 as the reference distance w1, the relative positions of the light emitting unit 20, the light receiving unit 30 and the measured surface 101 are arranged at the reference position for recording. The color of the sheet 100 can be measured with high accuracy, and the variation in the brightness to be measured can be suppressed.

In the present embodiment, the distances w1 to w3 between the light emitting unit 20 and the light receiving unit 30, which are the reflection position data, are the center position of the light source optical system 22 of the light emitting unit 20 in the second direction Y and the light receiving light. The distance from the center position of the light receiving optical system 31 of the unit 30 was set. Of course, the distance is not limited to this, and may be the distance between the exteriors of the light projecting unit 20 and the light receiving unit 30, or may be the distance between the reference marks. Further, when moving with reference to any one of the movable ranges of the light projecting unit holding unit 41 detected by the moving distance detecting means, the moving distance may be relative to this reference. ..

Further, as in the second embodiment described above, when measuring the thickness of the recording sheet 100, the distance between the light emitting unit 20 and the light receiving unit 30 and the third from the support member 8 of the color measuring unit 10 A conversion table associated with the height of the direction Z is prepared, and based on the conversion table, the color projection data having the highest brightness on each of the surface of the support member 8 and the measured surface 101 of the recording sheet 100 is measured. The height of the color measuring unit 10 from the support member 8 may be referred to from the distance between the unit 20 and the light receiving unit 30, and the thickness of the recording sheet 100 may be measured from the difference between the heights.

As described above, in the present embodiment, the changing unit 40 changes the distance between the light emitting unit 20 and the light receiving unit 30 in the surface direction of the surface to be measured 101, that is, the distance in the second direction Y. This also makes it possible to change the reflected position of the reflected light on the measured surface 101 of the recording sheet 100.

In the present embodiment, the changing unit 40 changes the position of the light emitting unit 20 in the second direction Y with respect to the light receiving unit 30, but the present invention is not particularly limited to this, and the light emitting unit 30 of the light emitting unit 30 is not particularly limited to this. The position of the second direction Y with respect to 20 may be changed.

(Embodiment 4)
18 to 20 are side views of a main part of an inkjet recording device which is an example of the liquid injection device according to the fourth embodiment of the present invention. The same members as those in the above-described embodiment are designated by the same reference numerals, and duplicate description will be omitted.

As shown in FIG. 18, the modified unit 40 of the present embodiment includes a third direction Z, a direction from the light emitting unit 20 toward the light receiving unit 30, and a second direction Y in the present embodiment. In, the irradiation angle of the light projecting unit 20 is changed. In other words, the irradiation angle of the light projecting unit 20 is changed with the axis parallel to the first direction X as the rotation axis.

Specifically, the changing unit 40 includes a light emitting unit holding unit 41A, which is fixed to the carriage 3 and rotatably holds the light emitting unit 20 in a direction including the third direction Z and the second direction Y. It is provided with a light projecting unit driving unit 42A that rotates the light projecting unit holding unit 41.

The light projecting unit driving unit 42A is not particularly limited as long as the light projecting unit holding unit 41A can be rotated, and for example, a motor or the like can be used. Further, although not particularly shown, the changing unit 40 is provided with a light projecting unit rotation angle detecting means such as a rotary encoder capable of detecting the rotation angle of the light projecting unit holding unit 41A.

By rotating the light projecting unit 20 by such a changing unit 40, the angle of the irradiation light emitted from the light projecting unit 20 is changed, and the reflected position of the reflected light on the measured surface 101 of the recording sheet 100 is changed. Can be changed.

As shown in FIG. 18, when the height (distance from the measured surface 101 to the color measuring unit 10) of the color measuring unit 10 from the measured surface 101 in the third direction Z is a reference value, the light is thrown. At the irradiation angle θ1 of the light unit 20 (here, the angle between the central axis of the light flux emitted from the light projecting unit 20 and the normal line of the measured surface 101), the central axis of the light beam emitted from the light projecting unit 20 is On the surface to be measured 101, the light receiving unit 30 coincides with the optical axis of the light receiving optical system 31, and the light receiving unit 30 can measure the color measurement data having the highest brightness. That is, the relative positional relationship between the light projecting unit 20, the light receiving unit 30, and the measured surface 101 as shown in FIG. 18 is a reference arrangement that enables accurate color measurement of the measured surface 101.

On the other hand, as shown in FIG. 19, when the height (distance) of the color measuring unit 10 from the measured surface 101 in the third direction Z is shorter (lower) than the example shown in FIG. 18, the light projecting unit At the irradiation angle θ1 of 20, the central axis of the light flux from the light projecting unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 do not match on the measured surface 101, and the light receiving unit 30 is the measured surface. Since the reflected light from the low illuminance region on 101 is received, the brightness measured by the light receiving unit 30 is lowered. In the present embodiment, the changing unit control unit 302 controls the changing unit 40 to change the angle (irradiation angle) between the central axis of the light beam emitted from the light projecting unit 20 and the normal line of the measured surface 101. The color measurement unit control unit 300 controls the color measurement unit 10 to measure the color of the surface to be measured 101, and the color measurement processing unit 301 digitizes the color measurement data in the color system to generate the color measurement data. It is stored in the storage unit 212 in association with the reflection position data. In the present embodiment, the angle between the central axis of the light flux emitted from the light projecting unit 20 and the normal line of the measured surface 101 is the reflection position data. Next, the brightness determination unit 303 determines the color measurement data having the highest brightness from the plurality of color measurement data. In the case of the recording sheet 100 shown in FIG. 19, the irradiation angle of the light projecting unit 20 is larger than the irradiation angle θ1 (here, the central axis of the light flux emitted from the light projecting unit 20 and the surface to be measured 101). The central axis of the luminous flux from the light projecting unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 coincide with each other on the measured surface 101, and the light receiving unit 30 is the highest. It is possible to measure the color measurement data of lightness.

Similarly, as shown in FIG. 20, when the height (distance) of the color measuring unit 10 from the measured surface 101 in the third direction Z is higher (longer) than the example shown in FIG. 18, the light projecting unit 20 At the irradiation angle θ1, the central axis of the light flux from the light projecting unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 do not match on the measured surface 101, and the light receiving unit 30 is on the measured surface 101. Since the reflected light is received from the region where the illuminance is low, the brightness measured by the light receiving unit 30 is lowered. Even in such a case, from a plurality of color measurement data measured while changing the angle (irradiation angle) between the central axis of the light flux emitted from the light projecting unit 20 and the normal line of the measured surface 101 as described above. Determine the color measurement data that has the highest brightness. In the case of the recording sheet 100 shown in FIG. 20, the irradiation angle of the light projecting unit 20 is smaller than the irradiation angle θ1, and the central axis of the light flux from the light projecting unit 20 and the light receiving optical system of the light receiving unit 30. The optical axis of 31 coincides with the surface to be measured 101, and the light receiving unit 30 can measure color measurement data having the highest brightness.

As shown in FIG. 18, when the brightness of the color measurement data at the irradiation angle θ1 which is the reference position is high, the height of the color measurement unit 10 from the measured surface 101 in the third direction Z is the reference height. Therefore, it is not necessary to further move the color measuring unit 10, and the position becomes the color measuring position. However, as described above, the difference between the current height of the third direction Z from the measured surface 101 of the color measuring unit 10 and the reference height is obtained from the displacement amount from the reference irradiation angle θ1 to the irradiation angles θ2 and θ3. By calculation, the color measuring unit 10 can be moved from the current height from the measured surface 101 to the reference height in FIGS. 19 and 20. Before performing color measurement to generate color conversion information, the height of the color measuring unit 10 from the surface to be measured 101 is set as the reference height, and the irradiation angle of the light projecting unit 20 is the reference irradiation angle. By changing to the angle θ1, even in the recording sheet 100 shown in FIGS. 19 and 20, the color measuring unit 10 is set to the reference height from the surface to be measured 101, and the irradiation angle of the light emitting unit 20 is set to θ1. The central axis of the light beam emitted from the light unit 20 can be aligned with the optical axis of the light receiving optical system 31 of the light receiving unit 30 on the surface to be measured 101.

That is, even if the thickness of the recording sheet 100 varies as shown in FIGS. 18 to 20, the height of the color measuring unit 10 in the third direction Z from the measured surface 101 is always the same reference height. The central axis of the luminous flux from the light emitting unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 are aligned on the recording sheet 100 with the irradiation angle from the light emitting unit 20 always set to the same reference irradiation angle θ1. Since the color can be measured at the highest brightness, it is possible to suppress the variation in the measurement conditions and suppress the variation in the brightness, and it is possible to perform the color measurement with high accuracy. That is, since the height of the color measuring unit 10 shown in FIG. 19 from the measured surface 101 is lower than the reference height of FIG. 18, the irradiation angle of the light projecting unit 20 is changed to project light on the measured surface 101. Even if the central axis of the light beam emitted from the unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 are aligned, the color measurement is performed while the height of the color measuring unit 10 from the measured surface 101 remains low. If this is done, the brightness measured will be higher than when the color is measured at the reference height. Similarly, since the height of the color measuring unit 10 shown in FIG. 20 from the measured surface 101 is higher than the reference height shown in FIG. 18, the irradiation angle of the light projecting unit 20 is changed on the measured surface 101. Even if the central axis of the light beam emitted from the light projecting unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 are aligned, the height of the color measuring unit 10 from the measured surface 101 remains high. When color is applied, the brightness measured is lower than when the color is measured at the reference height. Therefore, the difference between the current height of the color measuring unit 10 from the measured surface 101 and the reference height is calculated and measured based on the amount of displacement from the irradiation angle θ1 of the light projecting unit 20 to the irradiation angles θ2 and θ3. By moving the color unit 10 to the reference height and setting the irradiation angle of the light emitting unit 20 to the reference irradiation angle θ1, the relative position between the light emitting unit 20 and the light receiving unit 30 and the measured surface 101 is set to the reference position. The recording sheet 100 can be arranged and the color of the recording sheet 100 can be measured with high accuracy, and the variation in the brightness to be measured can be suppressed.

In this embodiment, the irradiation angles θ1 to θ3 of the light projecting unit 20 which are the reflection position data are the angles of the irradiation light (irradiation from the light projecting unit 20) with respect to the third direction Z (normal line of the measured surface 101). The angle of the central axis of the light beam to be formed). Of course, the present invention is not limited to this, and the angle may be set with respect to the irradiation angle at which the central axis of the light flux from the light projecting unit 20 is 45 degrees with respect to the third direction Z. Further, in the present embodiment, the light projecting unit 20 is rotated, but only the light source 21 and the light source optical system 22 provided in the light projecting unit 20 may be rotated, and the light source optical system 22 may be rotated. A prism, a reflecting mirror, or the like may be provided so as to rotate them.

Further, as in the second embodiment described above, when measuring the thickness of the recording sheet 100, the rotation angle of the light projecting unit 20 and the height in the third direction Z from the support member 8 of the color measuring unit 10 A conversion table associated with the above is prepared, and the rotation of the light projecting unit 20 that measures the highest brightness color measurement data on each of the surface of the support member 8 and the measured surface 101 of the recording sheet 100 based on the conversion table. The height of the color measuring unit 10 from the support member 8 may be referred to from an angle, and the thickness of the recording sheet 100 may be measured from the difference between the heights.

As described above, in the present embodiment, the changing unit 40 is in the direction including the third direction Z which is the normal direction of the surface to be measured 101 and the second direction Y from the light emitting unit 20 toward the light receiving unit 30. , The irradiation angle of the light projecting unit 20 was changed. This also makes it possible to change the reflected position of the reflected light on the measured surface 101 of the recording sheet 100.

In the present embodiment, the changing unit 40 changes the irradiation angle of the light projecting unit 20, but the modification unit 40 is not particularly limited to this, and receives light corresponding to the central axis of the light flux from the light projecting unit 20. The light receiving angle of the light receiving unit 30 (the angle of the light receiving optical system 31 of the light receiving unit 30 with respect to the normal of the surface to be measured 101) may be changed so that the unit 30 can receive light.

(Embodiment 5)
21 is a flowchart illustrating a driving method of an inkjet recording device which is an example of the liquid injection device according to the fifth embodiment of the present invention, and FIGS. 22 and 23 are side views of a main part of the inkjet recording device. Yes, FIGS. 24 to 29 are diagrams illustrating the illuminance distribution. The same members as those in the above-described embodiment are designated by the same reference numerals, and duplicate description will be omitted.

As shown in FIG. 21, the driving method of the liquid injection device of the present embodiment is recorded in step S11 at n points (n ≧ 2, n is a natural number) where the positions of the third direction Z of the color measuring unit 10 are different. The measured surface 101 of the sheet 100 is color-measured, and the generated color-measurement data is stored in the storage unit 212 in association with the color-measurement position (position in the third direction Z of the color-measurement unit 10). In the present embodiment, the color is measured at two locations (n = 2) where the position of the color measuring unit 10 is different in the third direction Z. Specifically, as shown in FIG. 22, the first color measuring position where the height of the color measuring unit 10 from the measured surface 101 is h1 and, as shown in FIG. 23, the color measuring unit 10 The color of the surface to be measured 101 of the recording sheet 100 is measured at the second color measurement position where the height from the surface to be measured 101 is h2 (h1 ≠ h2). That is, as shown in FIG. 22, the light emitting unit 20, the light receiving unit 30, and the recording sheet 100 are set to the first relative position (the first color measuring position where the height of the color measuring unit 10 is h1). The first color measurement value including the value indicating the brightness of the measured surface 101 of the recording sheet 100 is measured. Specifically, the first color measurement value (color measurement data) quantified in the color system from the result measured by the color measurement unit 10 at the first color measurement position is associated with the first color measurement position. It is stored in the storage unit 212. Further, as shown in FIG. 23, the light emitting unit 20, the light receiving unit 30, and the recording sheet 100 are placed in a second relative position different from the first relative position (the height of the color measuring unit 10 is h2). The color measurement position) is set, and the second color measurement value including the value indicating the brightness of the measured surface 101 of the recording sheet 100 is measured. Specifically, the second color measurement value (color measurement data) quantified in the color system from the result measured by the color measurement unit 10 at the second color measurement position is associated with the second color measurement position. It is stored in the storage unit 212. In the present embodiment, the first relative position (first color measurement position) and the second relative position (second color measurement position) are the second directions Y between the light projecting unit 20 and the light receiving unit 30. The interval between the above is a reference interval, and the angles of the central axis of the luminous flux emitted from the light projecting unit 20 with respect to the normal line of the measured surface 101 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 are the same at the reference angle. It is supposed to be. Using a recording sheet 100A having a reference thickness, the height of the color measuring unit 10 from the measured surface 101A is the reference height h0, and the height from the light projecting unit 20 with respect to the normal line of the measured surface 101A. The irradiation angle and the angle of the optical axis of the light receiving optical system 31 of the light receiving unit 30 are reference angles, and the distance between the light receiving unit 30 and the light emitting unit 20 in the second direction Y is the reference distance. Information on the relative position of the reference, where the central axis of the light beam from the unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 match on the measured surface 101A of the recording sheet 100A as a reference, is stored in the storage unit 212. It is remembered in. As a result, in the color measurement position for generating the color conversion information described later, the relative positions of the light projecting unit 20, the light receiving unit 30, and the measured surface 101 are arranged at the reference positions, and the recording sheet 100 is accurately measured. Colors can be obtained, and variations in color measurement accuracy due to variations in the thickness of the recording sheet 100 can be suppressed.

Here, as shown in FIGS. 24 to 26, the illuminance distribution of the luminous flux emitted from the light projecting unit 20 on the measured surface 101 has a high illuminance in the portion corresponding to the central axis of the luminous flux, and the outer periphery of the luminous flux is high. The color measurement when the illuminance of the part corresponding to the above is low will be described. When the color of the surface to be measured 101 irradiated with the light flux from the light projecting unit 20 is measured, high brightness is measured in the region where the light in the center of the light beam from the light projecting unit 20 is reflected, and the light is projected. The lower the brightness is measured in the region where the light farther from the central portion of the light flux from the light portion 20 is reflected. Therefore, as shown in FIG. 25, when the central axis of the light flux from the light projecting unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 coincide with each other on the measured surface 101, the illumination region and the illuminated area Since the light receiving areas generally overlap, the highest brightness is measured. On the other hand, as shown in FIGS. 24 and 26, when the central axis of the light flux from the light projecting unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 are displaced on the measured surface 101. Since the illumination area and the light receiving area are displaced from each other, a lower brightness is measured as compared with FIG. 25.

On the other hand, as shown in FIGS. 27 to 29, when the collimated light is irradiated from the light projecting unit 20, the illuminance distribution of the light beam emitted from the light projecting unit 20 on the measured surface 101 is the central axis of the light beam. It becomes almost uniform from to the periphery of the luminous flux. When the color of the measured surface 101 irradiated with the light flux from the light projecting unit 20 is measured, high brightness is measured when the area including the region where the light flux from the light projecting unit 20 is reflected is measured. When the area including only a part of the area where the light flux from the light projecting unit 20 is reflected is measured, the light receiving unit 30 measures the color of the unirradiated area, so that the low brightness is measured. Therefore, as shown in FIG. 28, when the central axis of the light flux from the light projecting unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 coincide with each other on the measured surface 101, the illumination region and the illuminated area Since the light receiving areas generally overlap, the highest brightness is measured. On the other hand, as shown in FIGS. 27 and 29, when the central axis of the light flux from the light projecting unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 are displaced on the measured surface 101. Since the illumination region and the light receiving region are displaced from each other, a lower brightness is measured as compared with FIG. 28.

From the above, regardless of whether the light beam has an illuminance distribution from the light projecting unit 20 or a light beam having a uniform illuminance distribution represented by collimated light, the light projecting unit 20 emits light. The highest brightness is measured when the central axis of the light flux and the optical axis of the light receiving optical system 31 of the light receiving unit 30 coincide with each other on the measured surface 101.

In this embodiment, the light receiving range on the measured surface 101 by the light receiving unit 30 is more than half of the irradiation range on the measured surface 101 of the recording sheet 100 due to the light flux emitted from the light projecting unit 20. preferable. For example, when the central axis of the light flux from the light projecting unit 20 is tilted with respect to the normal line of the measured surface 101, the illuminance distribution of the illumination range on the measured surface 101 is from the light projecting unit 20 to the measured surface 101. If the light receiving range of the light receiving unit 30 is smaller than half of the irradiation range of the light projecting unit 20, the central axis of the light flux from the light projecting unit 20 and the light receiving unit 30 receive light. The brightness determination value measured at a relative position where the optical axis of the optical system 31 does not match on the surface to be measured 101 is higher than the brightness determination position measured at the matching relative position, and is accurate. This is because it becomes impossible to set the color measurement position for generating the color conversion information. Incidentally, the irradiation range of the surface to be measured 101 by the light beam emitted from the light projecting unit 20 is, for example, the range of the light beam assumed from the light source optical system 22 of the light source unit 20, that is, the light source optical system 22. It can be the range obtained by the virtual circle based on the outer diameter. Similarly, the light receiving range of the surface 101 to be measured by the light receiving unit 30 is the light receiving range of the optical system assumed from the light receiving optical system 31 of the light receiving unit 30, that is, a virtual circle based on the outer diameter of the light receiving optical system 31. It can be in the range obtained by the inside.

Further, the color measurement at the first color measurement position and the second color measurement position may be performed by, for example, measuring the color of the measured surface 101 of the recording sheet 100, that is, the recording sheet 100 itself, and ejecting the color from the recording head. The color of the so-called printed patch, in which the ink droplets are landed on the surface to be measured 101, may be measured.

Next, in step S12, the position where the brightness of the color measurement value is the highest is set as the color measurement position for generating the color conversion information. That is, in the present embodiment, the lightness determination value L1 for determining the lightness measured at the first color measurement position, which is the first relative position, is the lightness measured at the second color measurement position, which is the second relative position. Since it is higher than the lightness determination value L2 (L1> L2), the first color measurement position (first relative position) is set as the color measurement position for generating the color conversion information. Specifically, the first color measurement position associated with the higher brightness determination value L1 (first color measurement value) is set in the storage unit 212 as the color measurement position for generating the color conversion information.

Next, in step S13, the color measurement of the patch is executed at the color measurement position. Then, in step S14, color conversion information is generated from the color measurement result of the patch. After that, printing is executed with the print data (image data) that has been color-converted based on the color conversion information. The patch can be formed by performing so-called printing in which ink droplets ejected from the recording head 1 land on the surface to be measured 101.

In this way, the color measurement accuracy is improved by performing color measurement at the first color measurement position and the second color measurement position, and performing color measurement of the patch with the first color measurement position having high brightness as the color measurement position. be able to. By the way, when the color measurement of the patch is performed at the second color measurement position where the lightness is low, the color measurement accuracy is low because the lightness is low, and when the image data is color-converted by the color conversion information based on the color measurement value, the color is changed. The reproducibility of is reduced. In the present implementation mobile phone, by improving the color measurement accuracy, the image data can be color-converted by the color conversion information based on the highly accurate color measurement value, and the color reproducibility can be improved.

In the present embodiment, in the first relative position (first color measurement position), as shown in FIG. 22, the central axis of the luminous flux emitted from the light projecting unit 20 and the light receiving optical system 31 of the light receiving unit 30 The case where the optical axis of the light axis coincides with the measured surface 101 is illustrated, but the present invention is not particularly limited to this, and the light flux emitted from the light projecting unit 20 at the first relative position (first color measurement position). The present embodiment also includes a case where the central axis and the optical axis of the light receiving optical system 31 of the light receiving unit 30 do not match on the measured surface 101. That is, the distance between the central axis of the luminous flux emitted from the light projecting unit 20 on the surface to be measured 101 at the first relative position (first color measurement position) and the optical axis of the light receiving optical system 31 of the light receiving unit 30. However, it suffices if it is shorter than the distance at the second relative position (second color measurement position). That is, the closer the distance between the central axis of the light beam emitted from the light projecting unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 on the measured surface 101, the higher the brightness of the color measurement data. Therefore, by setting the first color measurement position, which has a higher brightness determination value than the second color measurement position, to the color measurement position for generating color conversion information and performing color measurement, the light is received from the light projecting unit 20. By moving the relative position between the unit 30 and the surface to be measured 101 closer to the reference position, it is possible to perform color measurement with higher accuracy than when color measurement is performed at the second color measurement position.

Further, in the present embodiment, the color is measured at two points (n = 2), that is, the first relative position (first color measurement position) and the second relative position (second color measurement position). Not particularly limited to this, color measurement may be performed at three or more different relative positions. That is, in order to measure colors at a plurality of relative positions having different heights from the measured surface 101 of the color measuring unit 10 in the third direction Z, and to generate color conversion information at the relative positions where the highest brightness is measured. It may be the color measurement position (first relative position) of. When color measurement is performed at a plurality of relative positions of the color measurement unit 10 having different heights from the measured surface 101, the color measurement for generating color conversion information is performed at the relative position where the highest brightness is measured. It is desirable to set it to a position, but it is also possible to set a relative position where a higher lightness is measured, even if it is not the highest lightness, as a color measurement position for generating color conversion information. In this case as well, the color can be measured more accurately than when the relative position where the lower brightness is measured is set as the color measurement position for generating the color conversion information. As a result, the distance between the central axis of the light beam emitted from the light projecting unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 is shortened as much as possible, and the light projecting unit 20, the light receiving unit 30, and the surface to be measured 101 are measured. By moving the relative position to and closer to the reference position, the color measurement accuracy can be improved.

Further, by setting the color measurement position for generating the color conversion information based on the brightness determination value measured at the relative positions having different heights from the measured surface 101 of the color measurement unit 10 at three or more points. The central axis of the light flux from the light projecting unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 can be brought as close as possible on the measured surface 101 to measure the color of the measured surface 101 with higher accuracy. .. Therefore, in order to perform high-precision color measurement with higher brightness, it is preferable to perform color measurement at as many relative positions as possible with different heights from the measured surface 101 of the color measuring unit 10. However, by increasing the color measurement at the relative positions of the color measurement unit 10 having different heights from the measured surface 101, the number of color measurements increases and the color measurement takes time. Therefore, if the brightness when the color is measured accurately based on the experimental results or the like is known in advance, a threshold value is set based on the brightness, and the measured surface 101 of the color measuring unit 10 in the third direction Z is used. Color measurement is performed at multiple relative positions with different heights, and the relative position (first relative position) where the brightness higher than the predetermined lightness (threshold) is measured is the color measurement position for generating color conversion information. May be. As a result, the central axis of the light beam emitted from the light projecting unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 are arranged within a predetermined distance on the surface to be measured 101, and the color measurement accuracy is measured. It is not necessary to measure the color until the central axis of the light beam emitted from the light projecting unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 match on the surface to be measured 101. The number of colors can be reduced, and the time required for color measurement can be shortened.

As described above, from the inkjet recording head that injects liquid ink onto the recording sheet 100 that is the medium, the light projecting unit 20 that irradiates the measured surface 101 of the recording sheet 100 with light, and the light projecting unit 20. Drive of a liquid injection device including a light receiving unit 30 that receives light that is irradiated and reflected by the measured surface 101 of the recording sheet 100, and a color measuring unit 10 that measures the color of the measured surface 101 of the recording sheet 100. In this method, the light projecting unit 20, the light receiving unit 30, and the recording sheet 100 are set to the first color measurement position, which is the first relative position, and the surface 101 to be measured of the recording sheet 100 is irradiated from the light projecting unit 20. The light reflected by the light receiving unit 30 is received by the light receiving unit 30, and the first color measurement value including the value indicating the brightness of the measured surface 101 of the recording sheet 100 is measured, and the light projecting unit 20, the light receiving unit 30, and the recording sheet 100 are measured. Is set to the second color measurement position, which is a second relative position different from the first relative position, and the light emitted from the light projecting unit 20 and reflected by the measured surface 101 of the recording sheet 100 is transmitted by the light receiving unit 30. When the light is received and the second color measurement value indicating the brightness of the measured surface 101 of the recording sheet 100 is measured and the brightness of the first color measurement value is higher than the brightness of the second color measurement value, The first color measurement position, which is the first relative position, is set as the color measurement position, and the color of the recording sheet 100 measured at the color measurement position or the color based on the color measurement value of the patch printed on the recording sheet 100. The print data is color-converted by the conversion information.

In this way, color measurement is performed at the first relative position and the second relative position, the first relative position with high brightness is set as the color measurement position, and the color of the recording sheet 100 or the recording sheet is set at the color measurement position. By measuring the color of the patch printed on 100, highly accurate color measurement can be performed. Further, by color-converting the print data by the color conversion information based on the color measurement value, it is possible to realize printing with excellent color reproducibility.

Further, in the present embodiment, since the color measurement may be performed at at least two relative positions of the first relative position and the second relative position, the color measurement time can be shortened.

Further, since the thickness of the recording sheet 100 differs depending on the type, if the height of the support member 8 of the color measuring unit 10 from the support surface 8a is fixed, the recording sheet of the color measuring unit 10 depends on the thickness of the recording sheet 100. The height of the third direction Z from the measured surface 101 of 100 is different. However, in the present embodiment, color measurement is performed at the first relative position and the second relative position where the height of the third direction Z from the recording sheet 100 of the color measurement unit 10 is different, and higher brightness is measured. Since the relative position can be set as the color measurement position for generating the color conversion information, the color measurement unit 10 at the color measurement position for color measurement for generating the color conversion information due to the variation in the thickness of the recording sheet 100. It is possible to suppress the variation in the height from the surface to be measured 101 and improve the color measurement accuracy.

Further, the light emitting unit 20, the light receiving unit 30, and the recording sheet 100, which is a medium, include the first relative position and the second relative position, and the relative positions of the light emitting unit 20, the light receiving unit 30, and the recording sheet 100. Is set to a plurality of relative positions of three or more different locations, and at each of the plurality of relative positions, the light receiving unit 30 receives the light emitted from the light projecting unit 20 and reflected by the measured surface 101 of the recording sheet 100. It is preferable to measure the color measurement value indicating the brightness of the measured surface 101 of the recording sheet 100. According to this, the distance between the central axis of the light beam emitted from the light projecting unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 is made as short as possible, and the light emitting unit 20 and the light receiving unit 30 are measured. By moving the relative position with the surface 101 closer to the reference position, the color measurement accuracy can be improved.

Further, it is preferable that the brightness of the first color measurement value is the highest brightness among the brightness of the color measurement values measured at a plurality of relative positions. According to this, the distance between the central axis of the luminous flux emitted from the light projecting unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 can be shortened as much as possible, and the color can be measured with high brightness. Color accuracy can be improved.

(Embodiment 6)
FIG. 30 is a flowchart showing a driving method of an inkjet recording device which is an example of the liquid injection device according to the sixth embodiment of the present invention, and FIGS. 31 and 32 are side views of a main part of the inkjet recording device. .. The same members as those in the above-described embodiment are designated by the same reference numerals, and duplicate description will be omitted. In the present embodiment, the thickness of the recording sheet 100 is measured by using the color measuring unit 10 and the changing unit 40, and the color measuring position for generating the color conversion information is set as in the fifth embodiment.

As shown in FIG. 30, the driving method of the liquid injection device of the present embodiment is recorded in step S21 at m points (m ≧ 2, m is a natural number) where the position of the third direction Z of the color measuring unit 10 is different. A storage unit that measures the color of the support surface 8a of the support member 8 that supports the recording sheet 100, which is a medium, and associates the generated color measurement data with the color measurement position (position of the color measurement unit 10 in the third direction Z). Store in 212. In the present embodiment, the color is measured at two locations (m = 2) where the position of the color measuring unit 10 is different in the third direction Z. Specifically, as shown in FIG. 31, a third color measurement position at which the height of the color measurement unit 10 is h3, and as shown in FIG. 32, a height h4 (h3 ≠ h4) of the color measurement unit 10. The color of the support surface 8a of the support member 8 is measured at the fourth color measurement position. That is, as shown in FIG. 31, the light emitting unit 20, the light receiving unit 30, and the recording sheet 100 are set to the third relative position (the third color measuring position where the height of the color measuring unit 10 is h3). A third color measurement value including a value indicating the brightness of the support surface 8a of the support member 8 is measured. Specifically, the third color measurement value (color measurement data) quantified by the color system from the result measured by the color measurement unit 10 at the third color measurement position is associated with the third color measurement position. It is stored in the storage unit 212. Further, as shown in FIG. 32, the light emitting unit 20, the light receiving unit 30, and the recording sheet 100 are placed in a fourth relative position different from the third relative position (the fourth relative position where the height of the color measuring unit 10 is h4). The color measurement position) is set, and the fourth color measurement value including the value indicating the brightness of the support surface 8a of the support member 8 is measured. Specifically, the fourth color measurement value (color measurement data) quantified in the color system from the result measured by the color measurement unit 10 at the fourth color measurement position is associated with the fourth color measurement position. It is stored in the storage unit 212. In the present embodiment, the third relative position (third color measurement position) and the fourth relative position (fourth color measurement position) are the second directions Y between the light projecting unit 20 and the light receiving unit 30. The interval between the above is a reference interval, and the angles of the central axis of the luminous flux emitted from the light projecting unit 20 with respect to the normal line of the measured surface 101 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 are the same at the reference angle. It is supposed to be. The height of the color measuring unit 10 from the support surface 8a is the reference height h0, the irradiation angle from the light projecting unit 20 with respect to the normal line of the support surface 8a, and the light of the light receiving optical system 31 of the light receiving unit 30. The angle of the axis is the reference angle, the distance between the light receiving unit 30 and the light emitting unit 20 in the second direction Y is the reference distance, and the central axis of the light flux from the light emitting unit 20 and the light receiving unit 30 receive light. Information on the relative position of the reference, which coincides with the optical axis of the optical system 31 on the support surface 8a, is stored in the storage unit 212. As a result, in the color measurement position for generating the color conversion information described later, the relative positions of the light projecting unit 20, the light receiving unit 30, and the measured surface 101 are arranged at the reference positions, and the recording sheet 100 is accurately measured. Colors can be obtained, and variations in color measurement accuracy due to variations in the thickness of the recording sheet 100 can be suppressed, and the thickness of the recording sheet 100 can be measured with high accuracy.

Next, in step S22, the position having the highest brightness from the third color measurement value and the fourth color measurement value measured at the third color measurement position and the fourth color measurement position is set as the reference position. In the present embodiment, the lightness determination value LA1 for determining the brightness of the third color measurement value measured at the third color measurement position determines the brightness of the fourth color measurement value measured at the fourth color measurement position. Since it is higher than the lightness determination value LA2 (LA1> LA2), the third color measurement position is set as the reference position. Specifically, the third color measurement position associated with the higher brightness determination value LA1 (third color measurement value) is set in the storage unit 212 as a reference position for measuring the thickness of the recording sheet 100.

In the present embodiment, in the third relative position (third color measurement position), as shown in FIG. 31, the central axis of the luminous flux emitted from the light projecting unit 20 and the light receiving optical system 31 of the light receiving unit 30 The case where the optical axis of the light axis coincides with the support surface 8a is illustrated, but the present invention is not particularly limited to this, and the center of the light flux emitted from the light projecting unit 20 at the third relative position (third color measurement position). The present embodiment also includes a case where the axis and the optical axis of the light receiving optical system 31 of the light receiving unit 30 do not coincide with each other on the support surface 8a. That is, the distance between the central axis of the luminous flux emitted from the light projecting unit 20 at the third relative position (third color measurement position) and the optical axis of the light receiving optical system 31 of the light receiving unit 30 on the support surface 8a is , It suffices if it is shorter than the distance at the fourth relative position (fourth color measurement position). That is, the closer the distance between the central axis of the light beam emitted from the light projecting unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 on the support surface 8a, the higher the brightness of the color measurement data. By setting the third color measurement position, which has a higher brightness determination value than the fourth color measurement position, as the reference position and measuring the thickness of the recording sheet 100, the light projecting unit 20, the light receiving unit 30, and the support surface 8a can be obtained. It is possible to measure the thickness of the recording sheet 100 with higher accuracy than when the relative position of is closer to the reference position and the fourth color measurement position is set to the reference position to measure the thickness of the recording sheet 100. can. That is, by bringing the relative positions of the light projecting unit 20, the light receiving unit 30 and the support surface 8a closer to each other, and the relative positions of the light projecting unit 20 and the light receiving unit 30 and the measured surface 101 at the reference position, the reference position can be obtained. The thickness of the recording sheet 100 can be accurately measured from the difference between the height of the color measuring unit 10 from the support surface 8a and the height of the color measuring unit 10 from the support surface 8a at the color measuring position.

Further, in the present embodiment, the color is measured at two points (m = 2), that is, the third relative position (third color measurement position) and the fourth relative position (fourth color measurement position). Not particularly limited to this, color measurement may be performed at three or more different relative positions. That is, in order to measure the color at a plurality of relative positions having different heights from the support surface 8a of the color measuring unit 10 in the third direction Z, and to measure the thickness of the recording sheet 100 at the relative position where the highest brightness is measured. It may be a reference position (third relative position) of. When color measurement is performed at a plurality of relative positions having different heights from the support surface 8a of the color measurement unit 10, the relative position where the highest brightness is measured is used as a reference for measuring the thickness of the recording sheet 100. It is desirable to set it to the position. This is the height from the measured surface 101 of the color measuring unit 10 at the color measuring position for generating the color conversion information corresponding to the recording sheet 100, and the support surface 8a of the color measuring unit 10 at the reference position. This is because the thickness of the recording sheet 100 can be measured more accurately when the height is more equal to the height. However, if the relative position where the higher brightness is measured even if it is not the highest brightness can be set as the reference position for measuring the thickness of the recording sheet 100, the case where the relative position where the lower brightness is measured is set as the reference position. More accurately, the thickness of the recording sheet 100 can be measured. As a result, the distance between the central axis of the light beam emitted from the light projecting unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 on the support surface 8a is shortened as much as possible, and the light projecting unit 20 and the light receiving unit 20 are shortened. By moving the relative position between the 30 and the support surface 8a closer to the reference position, the measurement accuracy of the thickness of the recording sheet 100 can be improved.

Further, by setting the reference position for measuring the thickness of the recording sheet 100 based on the brightness determination value measured at the relative positions having different heights from the support surface 8a of the color measuring unit 10 at three or more places. The position where the central axis of the light flux from the light projecting unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 are as close as possible on the support surface 8a can be set as the reference position. Therefore, in order to measure the thickness of the recording sheet 100 with higher accuracy, it is preferable to measure the color at as many relative positions as possible with different heights from the support surface 8a of the color measuring unit 10. However, by increasing the number of color measurements at relative positions having different heights from the support surface 8a of the color measurement unit 10, the number of color measurements increases and it takes time to measure the colors. Therefore, if the brightness when the color is measured accurately based on the experimental results or the like is known in advance, a threshold value is set based on the brightness, and the color is measured from the support surface 8a of the color measuring unit 10 in the third direction Z. A reference position for measuring the thickness of the recording sheet 100 is the relative position (third relative position) in which color measurement is performed at a plurality of relative positions having different heights and the brightness higher than a predetermined brightness (threshold) is measured. May be. As a result, the central axis of the light beam emitted from the light projecting unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 are arranged within a predetermined distance on the support surface 8a as a reference position. It is necessary to improve the measurement accuracy of the thickness of the recording sheet 100 and to measure the color until the central axis of the luminous flux emitted from the light projecting unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 match. The number of color measurements can be reduced, and the time required for color measurement can be shortened.

Next, in step S23, the recording sheet 100, which is a medium, is installed on the support surface 8a of the support member 8.

Next, in steps S24 to S25, the location where the color measurement data having the highest brightness is measured is set as the color measurement position. Since steps S24 to S25 are the same as steps S11 to S12 of the fifth embodiment, detailed description thereof will be omitted.

Next, in step S26, the thickness of the recording sheet 100 is calculated from the difference between the reference position set in step S22 and the color measurement position set in step S25. That is, the third color measurement position in which the higher brightness was measured in the color measurement data of the support surface 8a of the support member 8 and the first color measurement data in which the color measurement data of the measured surface 101 of the recording sheet 100 was measured. The color measurement position is the measurement at the third color measurement position, which is the reference position, because the height of the support member 8 or the recording sheet 100 to be color measurement and the color measurement unit 10 are the same in the third direction Z. The thickness of the recording sheet 100 can be calculated from the difference between the height of the color unit 10 from the support surface 8a and the height of the color measurement unit 10 from the support surface 8a at the first color measurement position, which is the color measurement position.

Next, the thickness of the recording sheet 100 calculated in step S27 and the first color measurement value (of the recording sheet 100) corresponding to the first color measurement position which is the color measurement position stored in the storage unit 212 in step S24. The type of the recording sheet 100 is determined from the paper white value), and the color conversion information is generated based on the type of the recording sheet 100. After that, printing is executed with the print data (image data) that has been color-converted based on the color conversion information.

It should be noted that the color measurement position for generating the color conversion information of the so-called printed patch in which the ink droplets ejected from the recording head land on the surface to be measured 101 (the color measurement position set in step S25). It is also possible to measure the color with and execute printing based on the color conversion information generated based on the color measurement value.

By the way, there are multiple types of recording sheets with different materials and thicknesses depending on the manufacturer and application. Therefore, the recording sheet 100 can be specified based on the thickness of the recording sheet 100 and the whiteness value measured by the color measuring unit 10. Then, by specifying the recording sheet 100, the optimum printing settings can be made for the specified recording sheet 100. For example, the thickness and whiteness value of a plurality of types of recording sheets and the optimum print setting for each recording sheet are stored in advance as data, and the type of recording sheet 100 is determined from the thickness and whiteness value of the recording sheet 100. By specifying it, the optimum print setting for the specified recording sheet 100 can be recalled. Further, for example, the paper white value and thickness measured by the color measuring unit 10 in the past and the print setting set by the user when printing on the recording sheet 100 are stored, and the paper white value and thickness are used. When the same recording sheet 100 as the recording sheet 100 that has been color-measured and printed in the past is detected, the print setting set in the past may be recalled.

The recording sheet 100 has different color reproducibility, ink absorbency, susceptibility to kinking due to ink landing, drying time, and the like, depending on the type of material, thickness, and the like. Therefore, by specifying the recording sheet 100, a color based on the ratio of a plurality of element colors used by the inkjet recording apparatus I, for example, cyan (C), magenta (M), yellow (Y), and black (K). The reproducibility, the weight of the ink droplets (the amount of shot), the paper gap (PG), the moving speed of the carriage 3, the paper feeding speed, and the like can be set to the optimum values for the recording sheet 100. Incidentally, the color reproducibility may be corrected based on the result of color measurement by the color measuring unit 10 after being called by the print setting.

As described above, in the present embodiment, the light emitting unit 20, the light receiving unit 30, and the support member 8 that supports the side opposite to the measured surface 101 of the recording sheet 100, which is the medium, are located at a third relative position. A value indicating the brightness of the support surface of the support member 8 by setting the color measurement position and receiving the light emitted from the light projecting unit 20 and reflected by the support surface 8a supporting the recording sheet 100 of the support member 8 by the light receiving unit 30. The third color measurement value including the above is measured, the light emitting unit 20, the light receiving unit 30, and the support member 8 are set to a fourth relative position different from the third relative position, and irradiation is performed from the light emitting unit 20. The light reflected by the support surface of the support member 8 is received by the light receiving unit 30, the fourth color measurement value indicating the brightness of the support surface of the support member 8 is measured, and the brightness of the third color measurement value is the first. When the lightness of the color measurement value of 4 is higher than the brightness, the third relative position is set as the reference position, and the thickness of the recording sheet 100 is detected from the difference between the color measurement position and the reference position. In this way, by detecting the thickness of the recording sheet 100 by the color measuring unit 10, another sensor or the like for measuring the thickness of the recording sheet 100 is not required separately, and the cost can be reduced. Space for arranging the sensor is not required, and the size can be reduced. Further, by acquiring the thickness of the recording sheet 100, the paper gap, which is the distance between the recording sheet 100 and the recording head 1, can be controlled with high accuracy by the changing unit 40. Therefore, high-precision printing can be realized.

Further, in the present embodiment, the reference position for measuring the thickness of the recording sheet 100 is set by measuring the color of the support surface 8a of the support member 8 at the third color measurement position and the fourth color measurement position. However, by storing the reference position in, for example, the storage unit 212, it is not necessary to repeatedly acquire the reference position, and the color measurement time can be shortened. That is, since the reference position is not variable every time the color is measured but is always constant, the reference position is first acquired and stored in the storage unit 212, so that steps S21 and S22 are omitted at the time of color measurement. And the color measurement time can be shortened.

(Embodiment 7)
33 is a flowchart showing a driving method of an inkjet recording device which is an example of the liquid injection device according to the seventh embodiment of the present invention, and FIGS. 34 to 37 are side views of a main part of the inkjet recording device. .. The same members as those in the above-described embodiment are designated by the same reference numerals, and duplicate description will be omitted.

As shown in FIG. 33, in the driving method of the liquid injection device according to the seventh embodiment of the present invention, in step S31, the distance (distance) between the light emitting unit 20 and the light receiving unit 30 in the second direction Y is different. The measured surface 101 of the recording sheet 100 is color-measured at a location (n ≧ 2, n is a natural number), and the generated color measurement data is associated with the color measurement position (position of the color measurement unit 10 in the third direction Z). It is stored in the storage unit 212. In the present embodiment, the color is measured at two points (n = 2) where the distance between the light emitting unit 20 and the light receiving unit 30 in the second direction Y is different. Specifically, as shown in FIG. 37, the first color measurement position where the distance between the light emitting unit 20 and the light receiving unit 30 is the distance w1 and the distance between the light emitting unit 20 and the light receiving unit 30 are the distance w2 ( The color of the measured surface 101 of the recording sheet 100 is measured at the second color measurement position where w1 ≠ w2). That is, the light emitting unit 20, the light receiving unit 30, and the recording sheet 100 are set to the first relative position (the first color measurement position where the distance between the light emitting unit 20 and the light receiving unit 30 is w1), and the recording sheet 100 is set. A first color measurement value including a value indicating the brightness of the surface to be measured 101 is measured. Specifically, the first color measurement value (color measurement data) quantified in the color system from the result measured by the color measurement unit 10 at the first color measurement position is associated with the first color measurement position. It is stored in the storage unit 212. Further, a second relative position (the distance between the light projecting unit 20 and the light receiving unit 30 is w2), which is different from the first relative position of the light projecting unit 20, the light receiving unit 30, and the recording sheet 100. ), And the second color measurement value including the value indicating the brightness of the measured surface 101 of the recording sheet 100 is measured. Specifically, the second color measurement value (color measurement data) quantified in the color system from the result measured by the color measurement unit 10 at the second color measurement position is associated with the second color measurement position. It is stored in the storage unit 212. In the present embodiment, the first relative position (first color measurement position) and the second relative position (second color measurement position) are the heights (measurement) of the color measurement unit 10 from the measured surface 101. The distance between the color unit 10 and the recording sheet 100) is a reference height h0 or a predetermined height, and the central axis of the light beam emitted from the light projecting unit 20 with respect to the normal line of the measured surface 101 and the light receiving unit 30. The angle of the optical axis of the light receiving optical system 31 is the same as the reference angle. As a result, in the color measurement position for generating the color conversion information described later, the relative positions of the light projecting unit 20, the light receiving unit 30, and the measured surface 101 are arranged at the reference positions, and the recording sheet 100 is accurately measured. Colors can be obtained, and variations in color measurement accuracy due to variations in the thickness of the recording sheet 100 can be suppressed.

Further, the color measurement at the first color measurement position and the second color measurement position may be performed by, for example, measuring the color of the measured surface 101 of the recording sheet 100, that is, the recording sheet 100 itself, and ejecting the color from the recording head. The color of the so-called printed patch, in which the ink droplets are landed on the surface to be measured 101, may be measured.

In the present embodiment, as shown in FIG. 34, when a recording sheet 100A having a reference thickness is used, the light projecting unit 20 and the light receiving unit 30 can appropriately measure the color of the reference recording sheet 100A. And the relative position of the measured surface 101A is set as the reference relative position. At the reference relative position, the height of the color measuring unit 10 from the measured surface 101A is the reference height h0, the irradiation angle from the light projecting unit 20 with respect to the normal of the measured surface 101A, and the light reception of the light receiving unit 30. The angle of the optical axis of the optical system 31 is the reference angle, and the distance between the light receiving unit 30 and the light projecting unit 20 in the second direction Y is the reference distance w0. At such a reference relative position, the central axis of the light flux from the light projecting unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 coincide with each other on the measured surface 101A of the recording sheet 100A as a reference. That is, when the light projecting unit 20, the light receiving unit 30, and the measured surface 101A of the reference recording sheet 100A are arranged at the relative positions of the reference, the brightness of the color measurement data becomes the highest. Information on the relative position of the reference in which the light projecting unit 20, the light receiving unit 30, and the measured surface 101A are arranged at the reference position is stored in the storage unit 212.

In the present embodiment, the reference relative position (hereinafter, also simply referred to as the reference position) is set as the second color measurement position (second relative position). That is, a case where the distance (distance) w2 between the light receiving unit 30 and the light projecting unit 20 in the second direction Y at the second relative position is equal to the reference distance (distance) w0 will be described. When the measured surface 101 of the recording sheet 100 having a thickness different from that of the reference recording sheet 100A at such a second relative position (reference position) is measured, the recording sheet 100 with respect to the thickness of the reference recording sheet 100A is measured. Due to the difference in thickness, there is a difference in the height of the color measuring unit 10 in the third direction Z from the measured surface 101 with respect to the reference height h0, and the light flux from the light projecting unit 20 The central axis of the light receiving unit 30 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 are displaced on the measured surface 101.

For example, as shown in FIG. 35, when the thickness of the recording sheet 100 is thicker than the thickness of the reference recording sheet 100A, the central axis of the light flux from the light projecting unit 20 at the second color measurement position (reference position). And the optical axis of the light receiving optical system 31 of the light receiving unit 30 are at different positions on the measured surface 101. Further, as shown in FIG. 36, when the thickness of the recording sheet 100 is thinner than the thickness of the reference recording sheet 100A, similarly, at the second color measurement position (reference position), the light flux from the light projecting unit 20 is emitted. The central axis of the light receiving unit 30 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 are located at different positions on the surface to be measured 101.

In the present embodiment, as shown in FIG. 12, the changing unit control unit 302 controls the changing unit 40 to change the distance between the light emitting unit 20 and the light receiving unit 30 in the second direction Y, while measuring the color. The unit control unit 300 controls the color measurement unit 10 to perform color measurement. The color measurement processing unit 301 digitizes the measurement result of the color measurement unit 10 in a color system to generate color measurement data, and the color measurement data is associated with the reflection position data and stored in the storage unit 212. In the present embodiment, the distance between the light emitting unit 20 and the light receiving unit 30 in the second direction Y is the reflection position data. Next, the brightness determination unit 303 identifies the reflection position data associated with the color measurement data determined to have the highest brightness from the plurality of color measurement data. For example, when the thickness of the recording sheet 100 shown in FIG. 35 is thicker than the reference thickness of the recording sheet 100A, it is narrower than the distance w2 between the light emitting unit 20 and the light receiving unit 30 as shown in FIG. 37. At the interval w1, the central axis of the light flux from the light projecting unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 coincide with each other on the measured surface 101, and the light receiving unit 30 receives the strongest light. Can be done. Therefore, the distance w1 in the second direction Y between the light emitting unit 20 and the light receiving unit 30, which is the first color measurement position, is specified as the reflection position data having the highest brightness.

Next, in step S32, the distance w2 between the light emitting unit 20 and the light receiving unit 30, which is the reference position, and the first measurement, which is the reflection position data associated with the color measurement data determined to have the highest brightness in step S31. From the difference α (w2-w1) between the light emitting unit 20 and the light receiving unit 30 at the color position, the reference height h0 in the third direction Z from the measured surface 101A of the color measuring unit 10 and the third. The difference α'from the height h5 of the third direction Z from the measured surface 101 of the color measuring unit 10 at one color measuring position is calculated. For example, the difference α between the distance w2 between the light emitting unit 20 and the light receiving unit 30 at the reference position and the distance w1 between the light emitting unit 20 and the light receiving unit 30 at the first color measurement position, and the surface to be measured of the color measurement unit 10. A conversion table is prepared in which the difference α'between the reference height h0 from 101A and the height h5 of the color measuring unit 10 from the measured surface 101 at the first color measuring position is associated with each other, and the result is cast based on the conversion table. From the difference α of the distances w1 and w2 between the light unit 20 and the light receiving unit 30, the difference α ′ between the reference height h0 of the color measuring unit 10 in the third direction Z and the height h5 of the first color measuring position is obtained. do.

Next, in step S33, the color measuring unit 10 is moved from the height h5 of the first color measuring position from the measured surface 101 to the third direction Z by the difference α', and the color measuring unit 10 is measured. The height from the surface 101 is the same as the reference height h0. At the same time, the distance between the light emitting unit 20 and the light receiving unit 30 is moved to the same distance w2 as the reference position and set as a color measurement position for generating color conversion information. As a result, at the color measurement position for generating color conversion information, the height of the color measurement unit 10 from the recording sheet 100 is set to be the same as the reference height h0, and the central axis of the light flux from the light projection unit 20. And the optical axis of the light receiving optical system 31 of the light receiving unit 30 are aligned on the measured surface 101, and the relative positions of the light projecting unit 20, the light receiving unit 30 and the measured surface 101 are arranged at a reference position for recording. The color of the sheet 100 can be measured accurately.

Next, in step S34, the color measurement of the patch is executed at the color measurement position for generating the color conversion information. At this time, in the color measurement position for generating the color conversion information, the height of the color measurement unit 10 from the recording sheet 100 is set to the same height as the reference height h0, and the central axis of the light flux from the light projection unit 20. Since the optical axis of the light receiving optical system 31 of the light receiving unit 30 can be aligned with the optical axis of the light receiving optical system 31 on the surface to be measured 101, a third direction of the color measuring unit 10 from the recording sheet 100 when performing color measurement is performed. It is possible to suppress the variation in the height of Z and suppress the variation in the brightness. Therefore, the relative position between the light projecting unit 20, the light receiving unit 30, and the surface to be measured 101 can be arranged at a reference position, and high-precision color measurement of the recording sheet 100 can be performed. The patch can be formed by performing so-called printing, in which ink droplets ejected from the recording head land on the surface to be measured 101.

Then, in step S35, color conversion information is generated from the color measurement result of the patch. After that, printing is executed based on the color conversion information.

In the present embodiment, in the first relative position (first color measurement position), as shown in FIG. 37, the central axis of the luminous flux emitted from the light projecting unit 20 and the light receiving optical system 31 of the light receiving unit 30. The case where the optical axis of the light axis coincides with the measured surface 101 is illustrated, but the present invention is not particularly limited to this, and the light beam emitted from the light projecting unit 20 at the first relative position (first color measurement position). The case where the central axis and the optical axis of the light receiving optical system 31 of the light receiving unit 30 do not match is also included in the present embodiment. That is, the distance between the central axis of the luminous flux emitted from the light projecting unit 20 at the first relative position (first color measurement position) and the optical axis of the light receiving optical system 31 of the light receiving unit 30 on the measured surface 101. However, it suffices if it is shorter than the distance at the second relative position (second color measurement position). That is, the closer the distance between the central axis of the light beam emitted from the light projecting unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 on the measured surface 101, the higher the brightness. The second color measurement position and reference by performing color measurement at the color measurement position set as described above based on the difference α between the first color measurement position and the reference position, which has a higher brightness judgment value than the color position. Compared to the case where color measurement is performed at the color measurement position set as described above based on the difference α from the position, the relative position between the light projecting unit 20 and the light receiving unit 30 and the measured surface 101 is a more reference position. It is possible to measure colors with high accuracy by approaching.

Further, in the present embodiment, the color is measured at two points (n = 2), that is, the first relative position (first color measurement position) and the second relative position (second color measurement position). Not particularly limited to this, color measurement may be performed at three or more different relative positions. That is, color measurement is performed at a plurality of relative positions where the distance between the light projecting unit 20 and the light receiving unit 30 is different, and the relative position where the highest brightness is measured is determined based on the difference α between the first relative position and the reference position. The color measurement position for generating the color conversion information may be set as in. When color measurement is performed at a plurality of relative positions where the distance between the light projecting unit 20 and the light receiving unit 30 is different, as described above, the difference α between the relative position where the highest brightness is measured and the reference position is used. It is desirable to set the color measurement position to generate the color conversion information, but the color conversion as described above is based on the difference α between the relative position where the higher lightness is measured and the reference position, even if the lightness is not the highest. It is also possible to set the color measurement position for generating information. In this case as well, color measurement should be performed more accurately than when the color measurement position for generating color conversion information is set as described above based on the difference α between the relative position where the lower brightness is measured and the reference position. Can be done. As a result, color conversion information is generated based on the difference between the relative position and the reference position where the distance between the central axis of the light beam emitted from the light projecting unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 is as short as possible. Since the color measurement position can be set, the relative positions of the light projecting unit 20, the light receiving unit 30, and the measured surface 101 at the color measurement position for generating color conversion information should be as close as possible to the reference position. Therefore, it is possible to measure the color with high brightness and improve the color measurement accuracy.

Further, the color is set by setting the color measurement position for generating the color conversion information based on the brightness determination value measured at the relative positions where the distance between the light emitting unit 20 and the light receiving unit 30 are different from each other at three or more places. In the color measurement position for generating conversion information, the relative position between the light projecting unit 20, the light receiving unit 30, and the measured surface 101 can be as close as possible to the reference position, so that higher brightness and higher accuracy color measurement can be achieved. It can be carried out. Therefore, in order to measure the color of the surface to be measured 101 with higher accuracy, it is preferable to measure the color at as many relative positions as possible with different distances between the light emitting unit 20 and the light receiving unit 30. However, by increasing the color measurement at the relative positions where the distance between the light projecting unit 20 and the light receiving unit 30 is different, the number of color measurements increases and the color measurement takes time. Therefore, if the brightness when the color is measured accurately based on the experimental results or the like is known in advance, a threshold value is set based on the brightness, and a plurality of relatives having different distances between the light emitting unit 20 and the light receiving unit 30 are set. Color measurement is performed at the position, and the color measurement position for generating color conversion information is set as described above based on the relative position (first relative position) where the brightness higher than the predetermined brightness (threshold) is measured. You may. As a result, color conversion is performed based on the difference between the relative position and the reference position where the distance between the central axis of the light beam emitted from the light projecting unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 is within a predetermined range. Since the color measurement position for generating information can be set, the relative position between the light projecting unit 20, the light receiving unit 30, and the measured surface 101 at the color measurement position for generating color conversion information is set as a reference position. It is possible to improve the color measurement accuracy by making it as close as possible, and it is not necessary to measure the color until the central axis of the light beam emitted from the light projecting unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 match. , The number of color measurements can be reduced, and the time required for color measurement can be shortened.

In the above example, the reference position is the position where the central axis of the light flux from the projection unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 coincide with each other on the measured surface 101A of the recording sheet 100A as a reference. Therefore, the reference height in the third direction Z calculated from the difference α of the distance between the light emitting unit 20 and the light receiving unit 30 with respect to the distance between the light emitting unit 20 and the light receiving unit 30 as a reference, or the difference α of the distance. The thickness of the color-measured recording sheet 100 (for example, the thickness of the reference recording sheet 100A + the difference in height α') is calculated from the difference α'between h0 and the height h5 of the first color measurement position. You can also. By grasping the thickness of the recording sheet 100 to be color-measured in this way, a sensor or the like for measuring the thickness of the recording sheet 100 is not required separately, the cost can be reduced, and the space for arranging the sensors can be reduced. It is also unnecessary and can be miniaturized. Further, by acquiring the thickness of the recording sheet 100, the paper gap, which is the distance between the recording sheet 100 and the recording head 1, can be controlled with high accuracy by the changing unit 40. Therefore, high-precision printing can be realized.

Further, in the present embodiment, the reference position is the central axis of the light flux from the light projecting unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 on the measured surface 101A of the recording sheet 100A having a reference thickness. Since the positions coincide with each other, when the recording sheet 100 having the same thickness as the recording sheet 100A having the reference thickness is used, the color can be measured without adjusting the height. Therefore, the color measurement time can be shortened.

Further, in the above-mentioned example, the reference position coincides with the central axis of the light flux from the light projecting unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 on the measured surface 101A of the recording sheet 100A as a reference. However, the position is not limited to this.

For example, the reference position may be a position where the central axis of the light flux from the light projecting unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 coincide with each other on the support surface 8a of the support member 8. Also by this, it is also possible to set the color measurement position for generating the color conversion information from the difference α'between the reference height h0 in the third direction Z and the height h5 of the first color measurement position. It is also possible to calculate a thickness of 100.

Further, for example, the reference position may be any position. As described above, the difference between the distance between the light emitting unit 20 and the light receiving unit 30 at an arbitrary reference position and the distance between the light emitting unit 20 and the light receiving unit 30 at the relative position (first relative position) where the highest brightness is measured. α is obtained, and the height of the color measuring unit 10 at an arbitrary reference position in the third direction Z from the difference α of this interval and the height of the color measuring unit 10 from the measured surface 101 at the relative position where the highest brightness is measured. The difference α'is calculated, and the color measuring unit 10 is moved to the third direction Z by the distance obtained by adding the difference between the height of the color measuring unit 10 at an arbitrary reference position and the reference height h0 to the difference α'. However, if the color measurement is performed in the moved state, the color measurement can always be performed at the same height h0 as the reference height h0. Therefore, it is possible to suppress the variation in the height of the color measuring unit 10 from the measured surface 101 at the color measuring position for generating the color conversion information due to the variation in the thickness of the recording sheet 100, and it is possible to suppress the variation. Highly accurate color measurement can be performed by arranging the relative positions of the light unit 20, the light receiving unit 30, and the surface to be measured 101 at reference positions.

Further, in the above-mentioned example, the reference position is the second color measurement position, which is the second relative position, but the present invention is not particularly limited to this, and the reference position and the second relative position may be different. good.

As described above, in the present embodiment, the recording head 1 which is an example of the liquid injection head for injecting liquid ink onto the recording sheet 100 which is a medium and the measured surface 101 of the recording sheet 100 are irradiated with light. A color measurement unit 20 includes a light projecting unit 20 and a light receiving unit 30 that receives light emitted from the light projecting unit 20 and reflected by the measured surface 101 of the recording sheet 100, and measures the color of the measured surface 101 of the recording sheet 100. In a method of driving a liquid injection device including the unit 10, the light projecting unit 20, the light receiving unit 30, and the recording sheet 100 are set to the first relative positions, and the light emitting unit 20 irradiates the recording sheet 100. The light reflected by the surface to be measured 101 is received by the light receiving unit 30, the first color measurement value including the value indicating the brightness of the surface to be measured 101 of the recording sheet 100 is measured, and the light projecting unit 20 and the light receiving unit 30 are measured. And the recording sheet 100 are set to a second relative position different from the first relative position, and the light emitted from the light projecting unit 20 and reflected by the measured surface 101 of the recording sheet 100 is received by the light receiving unit 30. When the lightness of the second colorimetric value indicating the lightness of the measured surface 101 of the recording sheet 100 is measured and the lightness of the first colorimetric value is higher than the lightness of the second colorimetric value, the first color is measured. The recording sheet 100 in which the relative positions of the light emitting unit 20, the light receiving unit 30, and the recording sheet 100 are set as the color measurement positions based on the difference between the relative positions and the preset reference relative positions, and the colors are measured at the color measurement positions. The print data is color-converted by the color conversion information based on the color of the light or the color measurement value of the patch printed on the recording sheet 100. Thus, when the first colorimetric value at the first relative position has a higher brightness than the second colorimetric value at the second relative position, the difference between the first relative position and the reference relative position Based on this, the light projecting unit 20, the light receiving unit 30, and the surface to be measured 101 of the recording sheet (medium) 100 are set to color measurement positions that have the same color measurement conditions as the reference relative positions, and color measurement is performed. Therefore, even if the thickness of the recording sheet 100 varies, the color measurement condition, particularly the height of the color measurement unit 10 from the measured surface 101, can always be measured under the same condition at the color measurement position. Therefore, highly accurate color measurement can be performed.

Further, in the present embodiment, since the color measurement may be performed at at least two relative positions of the first relative position and the second relative position, the color measurement time can be shortened.

Further, in the present embodiment, the first relative position and the second relative position are projected in a direction intersecting the third direction Z which is the normal direction of the measured surface 101 of the recording sheet 100 which is a medium. It is preferable that the distance between the unit 20 and the light receiving unit 30 is different. As a result, the reflected position of the reflected light on the measured surface 101 of the recording sheet 100 can be changed to perform highly accurate color measurement.

In the present embodiment, the changing unit 40 changes the position of the light emitting unit 20 in the second direction Y with respect to the light receiving unit 30, but the present invention is not particularly limited to this, and the light emitting unit 30 of the light emitting unit 30 is not particularly limited to this. The position of the second direction Y with respect to 20 may be changed.

Further, in the present embodiment, when the brightness of the first colorimetric value is higher than the brightness of the second colorimetric value, the distance between the light emitting unit 20 and the light receiving unit 30 at the first relative position is determined. The color measuring unit 10 is placed in the third direction Z, which is the normal direction of the surface to be measured 101, by the distance calculated from the difference between the distance between the light emitting unit 20 and the light receiving unit 30 at the preset reference relative position. It is preferable to move to. According to this, even if the thickness of the recording sheet 100 varies, the height of the color measuring unit 10 from the measured surface 101 can always be measured under the same conditions, so that highly accurate color measurement can be performed. It can be carried out.

Further, the first relative position is preferably the relative position in which the higher brightness is measured among the plurality of relative positions of the light projecting unit 20, the light receiving unit 30, and the recording sheet 100. According to this, the color conversion information is based on the difference between the relative position and the reference position where the distance between the central axis of the light beam emitted from the light projecting unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 is as short as possible. Since it is possible to set the color measurement position for generating the It is possible to improve the color measurement accuracy by making it closer.

Further, the first relative position is preferably the relative position where the highest brightness is measured among the plurality of relative positions of the light emitting unit 20, the light receiving unit 30, and the recording sheet 100. According to this, the color conversion information is based on the difference between the relative position and the reference position where the distance between the central axis of the light beam emitted from the light projecting unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 is as short as possible. Since it is possible to set the color measurement position for generating the It is possible to measure colors with high brightness by bringing them closer, and it is possible to improve the color measurement accuracy.

(Embodiment 8)
38 is a flowchart showing a driving method of an inkjet recording device which is an example of the liquid injection device according to the eighth embodiment of the present invention, and FIGS. 39 to 42 are side views of a main part of the inkjet recording device. .. The same members as those in the above-described embodiment are designated by the same reference numerals, and duplicate description will be omitted.

As shown in FIG. 38, the driving method of the liquid injection device according to the eighth embodiment of the present invention is a recording sheet in step S41 at n points (n ≧ 2, n is a natural number) where the irradiation angles of the light projecting unit 20 are different. The measured surface 101 of 100 is measured in color, and the generated color measurement data is stored in the storage unit 212 in association with the color measurement position (position in the third direction Z of the color measurement unit 10). In the present embodiment, the color is measured at two points (n = 2) where the irradiation angles of the light projecting unit 20 are different. Specifically, as shown in FIG. 42, the irradiation angle of the light projecting unit 20 is the irradiation angle θ1 (here, the angle between the central axis of the light flux emitted from the light projecting unit 20 and the normal line of the measured surface 101). ), And the irradiation angle of the light projecting unit 20 is the irradiation angle θ2 (here, the angle between the central axis of the light flux emitted from the light projecting unit 20 and the normal line of the measured surface 101). Then, the color of the measured surface 101 of the recording sheet 100 is measured at the second color measurement position where θ1 ≠ θ2). That is, the light projecting unit 20, the light receiving unit 30, and the recording sheet 100 are set to the first relative position (the first color measurement position where the irradiation angle of the light projecting unit 20 is θ1), and the measured surface of the recording sheet 100 is measured. A first colorimetric value including a value indicating the brightness of 101 is measured. Specifically, the first color measurement value (color measurement data) quantified in the color system from the result measured by the color measurement unit 10 at the first color measurement position is associated with the first color measurement position. It is stored in the storage unit 212. Further, the light projecting unit 20, the light receiving unit 30, and the recording sheet 100 are set to a second relative position (second color measurement position where the irradiation angle of the light projecting unit 20 is θ2) different from the first relative position. , A second color measurement value including a value indicating the brightness of the measured surface 101 of the recording sheet 100 is measured. Specifically, the second color measurement value (color measurement data) quantified in the color system from the result measured by the color measurement unit 10 at the second color measurement position is associated with the second color measurement position. It is stored in the storage unit 212. In the present embodiment, the first relative position (first color measurement position) and the second relative position (second color measurement position) are the third direction Z from the recording sheet 100 of the color measurement unit 10. The height of is the reference height h0 or a predetermined height, and the angle of the optical axis of the light receiving optical system 31 of the light receiving unit 30 with respect to the normal of the measured surface 101 is the reference angle, and the light projecting unit 20 The distance between the light receiving unit 30 and the second direction Y is the same as the reference distance w0. As a result, in the color measurement position for generating the color conversion information described later, the relative positions of the light projecting unit 20, the light receiving unit 30, and the measured surface 101 are arranged at the reference positions, and the recording sheet 100 is accurately measured. Colors can be obtained, and variations in color measurement accuracy due to variations in the thickness of the recording sheet 100 can be suppressed.

Further, the color measurement at the first color measurement position and the second color measurement position may be performed by, for example, measuring the color of the measured surface 101 of the recording sheet 100, that is, the recording sheet 100 itself, and ejecting the color from the recording head. The color of the so-called printed patch, in which the ink droplets are landed on the surface to be measured 101, may be measured.

In the present embodiment, as shown in FIG. 39, when a recording sheet 100A having a reference thickness is used, the light projecting unit 20 and the light receiving unit 30 can appropriately measure the color of the reference recording sheet 100A. And the relative position of the measured surface 101A is set as the reference relative position. At the reference relative position, the height of the color measuring unit 10 from the measured surface 101A is the reference height h0, and the distance between the light emitting unit 20 and the light receiving unit 30 in the second direction Y is the reference distance w0. The angle of the optical axis of the light receiving optical system 31 of the light receiving unit 30 with respect to the normal of the measured surface 101A is a reference angle, and the irradiation angle of the light projecting unit 20 with respect to the normal of the measured surface 101A (of the light beam). The angle of the central axis) is the reference angle θ0. At such a reference relative position, the central axis of the light flux from the light projecting unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 coincide with each other on the measured surface 101A of the recording sheet 100A as a reference. That is, when the light projecting unit 20, the light receiving unit 30, and the measured surface 101A of the reference recording sheet 100A are arranged at the relative positions of the reference, the brightness of the color measurement data becomes the highest. Information on the relative position of the reference in which the light projecting unit 20, the light receiving unit 30, and the measured surface 101 are arranged at the reference position is stored in the storage unit 212.

In the present embodiment, the reference relative position (hereinafter, also simply referred to as the reference position) is set as the second color measurement position (second relative position). That is, a case where the irradiation angle (angle of the central axis of the light beam) θ2 of the light projecting unit 20 with respect to the normal of the surface to be measured 101A at the second relative position is equal to the reference angle θ0 will be described. When the measured surface 101 of the recording sheet 100 having a thickness different from that of the reference recording sheet 100A at such a second relative position (reference position) is measured, the recording sheet 100 with respect to the thickness of the reference recording sheet 100A is measured. Due to the difference in thickness, there is a difference in the height of the color measuring unit 10 in the third direction Z from the measured surface 101 with respect to the reference height h0, and the light flux from the light projecting unit 20 The central axis of the light receiving unit 30 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 are displaced on the measured surface 101.

For example, as shown in FIG. 40, when the thickness of the recording sheet 100 is thicker than the thickness of the reference recording sheet 100A, the central axis of the light flux from the light projecting unit 20 at the second color measurement position (reference position). And the optical axis of the light receiving optical system 31 of the light receiving unit 30 are at different positions on the measured surface 101. Further, as shown in FIG. 41, when the thickness of the recording sheet 100 is thinner than the thickness of the reference recording sheet 100A, similarly, at the second color measurement position (reference position), the light flux from the light projecting unit 20 is emitted. The central axis of the light receiving unit 30 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 are located at different positions on the surface to be measured 101.

In the present embodiment, the changing unit control unit 302 controls the changing unit 40 to change the central axis (irradiation angle of the light emitting unit 20) of the light beam emitted from the light emitting unit 20 with respect to the normal line of the measured surface 101. At the same time, the color measuring unit control unit 300 controls the color measuring unit 10 to perform color measurement. The color measurement processing unit 301 digitizes the measurement result of the color measurement unit 10 in a color system to generate color measurement data, and the color measurement data is associated with the reflection position data and stored in the storage unit 212. In the present embodiment, the angle of the central axis of the light beam emitted from the light projecting unit 20 with respect to the normal of the surface to be measured 101 (the irradiation angle of the light projecting unit 20) is the reflection position data. Next, the brightness determination unit 303 identifies the reflection position data associated with the color measurement data determined to have the highest brightness from the plurality of color measurement data. For example, when the thickness of the recording sheet 100 shown in FIG. 40 is thicker than the thickness of the reference recording sheet 100A, as shown in FIG. 42, the irradiation angle θ1 is larger than the irradiation angle θ2 of the light projecting unit 20. The central axis of the light beam from the light projecting unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 coincide with each other on the measured surface 101, and the light receiving unit 30 can receive the strongest light. Therefore, the irradiation angle θ1 of the light projecting unit 20, which is the first color measurement position, is specified as the reflection position data having the highest brightness.

Next, in step S42, the irradiation angle θ2 of the light projecting unit 20 which is the reference position and the projection at the first color measurement position which is the reflection position data associated with the color measurement data determined to have the highest brightness in step S41. From the difference α (θ2-θ1) from the irradiation angle θ1 of the light unit 20, the reference height h0 in the third direction Z from the measured surface 101A of the color measurement unit 10 and the color measurement unit at the first color measurement position. The difference α'from the height h5 in the third direction Z from the measured surface 101 of 10 is calculated. For example, the difference α between the irradiation angle θ2 of the light projecting unit 20 at the reference position and the irradiation angle θ1 of the light projecting unit 20 at the first color measurement position, and the reference height h0 of the color measurement unit 10 from the measured surface 101A. A conversion table is prepared in which the difference α'from the height h5 of the color measurement unit 10 from the measured surface 101 at the first color measurement position is associated with the conversion table, and the irradiation angle θ1 of the light projecting unit 20 is based on the conversion table. From the difference α of θ2, the difference α ′ between the reference height h0 of the color measuring unit 10 in the third direction Z and the height h5 of the first color measuring position is acquired.

Next, in step S43, the color measuring unit 10 is moved from the height h5 from the measured surface 101 at the first color measuring position to the third direction Z by the difference α', and the color measuring unit 10 is measured. The height from the surface 101 is the same as the reference height h0. At the same time, the irradiation angle of the light projecting unit 20 is moved from θ1 to the same irradiation angle θ2 as the reference position, and is set as a color measurement position for generating color conversion information. As a result, at the color measurement position for generating color conversion information, the height of the color measurement unit 10 from the recording sheet 100 is set to be the same as the reference height h0, and the central axis of the light flux from the light projection unit 20. And the optical axis of the light receiving optical system 31 of the light receiving unit 30 are aligned on the measured surface 101, and the relative positions of the light projecting unit 20, the light receiving unit 30 and the measured surface 101 are arranged at a reference position for recording. The color of the sheet 100 can be measured accurately.

Next, in step S44, the color measurement of the patch is executed at the color measurement position for generating the color conversion information. At this time, in the color measurement position for generating the color conversion information, the height of the color measurement unit 10 from the recording sheet 100 is set to the same height as the reference height h0, and the central axis of the light flux from the light projection unit 20. Since the optical axis of the light receiving optical system 31 of the light receiving unit 30 can be aligned with the optical axis of the light receiving optical system 31 on the surface to be measured 101, a third direction of the color measuring unit 10 from the recording sheet 100 when performing color measurement is performed. It is possible to suppress the variation in the height of Z and suppress the variation in the brightness. Therefore, the relative positions of the light emitting unit 20, the light receiving unit 30, and the surface to be measured 101 are always arranged at the reference positions, and the recording sheet 100 can be measured with high accuracy. The patch can be formed by performing so-called printing in which ink droplets ejected from the recording head 1 land on the surface to be measured 101.

Then, in step S45, color conversion information is generated from the color measurement result of the patch. After that, printing is executed based on the color conversion information.

In the present embodiment, in the first relative position (first color measurement position), as shown in FIG. 42, the central axis of the luminous flux emitted from the light projecting unit 20 and the light receiving optical system 31 of the light receiving unit 30. The case where the optical axis of the light axis coincides with the measured surface 101 is illustrated, but the present invention is not particularly limited to this, and the light beam emitted from the light projecting unit 20 at the first relative position (first color measurement position). The case where the central axis and the optical axis of the light receiving optical system 31 of the light receiving unit 30 do not match is also included in the present embodiment. That is, the distance between the central axis of the luminous flux emitted from the light projecting unit 20 at the first relative position (first color measurement position) and the optical axis of the light receiving optical system 31 of the light receiving unit 30 on the measured surface 101. However, it suffices if it is shorter than the distance at the second relative position (second color measurement position). That is, the closer the distance between the central axis of the light beam emitted from the light projecting unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 on the measured surface 101, the higher the brightness. The second color measurement position and reference by performing color measurement at the color measurement position set as described above based on the difference α between the first color measurement position and the reference position, which has a higher brightness judgment value than the color position. Compared to the case where color measurement is performed at the color measurement position set as described above based on the difference α from the position, the relative position between the light projecting unit 20 and the light receiving unit 30 and the measured surface 101 is a more reference position. It is possible to measure colors with high accuracy by approaching.

Further, in the present embodiment, the color is measured at two points (n = 2), that is, the first relative position (first color measurement position) and the second relative position (second color measurement position). Not particularly limited to this, color measurement may be performed at three or more different relative positions. That is, the color is measured at a plurality of relative positions having different irradiation angles of the light projecting unit 20, and the relative position where the highest brightness is measured is the color as described above based on the difference α between the first relative position and the reference position. The color measurement position for generating the conversion information may be set. When color measurement is performed at a plurality of relative positions having different irradiation angles of the light projecting unit 20, color conversion information is obtained as described above based on the difference α between the relative position where the highest brightness is measured and the reference position. It is desirable to set the color measurement position for generation, but the color conversion information is generated as described above based on the difference α between the relative position where the higher brightness is measured and the reference position, even if it is not the highest brightness. It is also possible to set the color measurement position for this. In this case as well, color measurement should be performed more accurately than when the color measurement position for generating color conversion information is set as described above based on the difference α between the relative position where the lower brightness is measured and the reference position. Can be done. As a result, the difference between the relative position and the reference position where the distance between the central axis of the light beam emitted from the light projecting unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 on the measured surface 101 is as short as possible. Since the color measurement position for generating color conversion information can be set based on the above, the relative positions of the light projecting unit 20, the light receiving unit 30, and the measured surface 101 at the color measurement position for generating color conversion information can be set. It is possible to measure the color with high brightness by making it as close as possible to the reference position, and it is possible to improve the color measurement accuracy.

Further, the color conversion information is generated by setting the color measurement position for generating the color conversion information based on the brightness determination value measured at the relative positions where the irradiation angles of the three or more light projecting units 20 are different. Since the relative positions of the light projecting unit 20, the light receiving unit 30, and the surface to be measured 101 can be as close as possible to the reference position at the color measurement position, it is possible to perform highly accurate color measurement with higher brightness. .. Therefore, in order to measure the color of the surface to be measured 101 with higher accuracy, it is preferable to measure the color at as many relative positions as possible with different irradiation angles of the light projecting unit 20. However, by increasing the color measurement at the relative positions where the irradiation angles of the light projecting unit 20 are different, the number of color measurements increases and the color measurement takes time. Therefore, if the brightness when the color is measured accurately based on the experimental results is known in advance, a threshold value is set based on the brightness, and the color is measured at a plurality of relative positions where the irradiation angle of the light projecting unit 20 is different. The color measurement position for generating the color conversion information may be set as described above based on the relative position (the first relative position) in which the brightness higher than the predetermined brightness (threshold) is measured. As a result, the relative position and the reference position where the distance between the central axis of the light beam emitted from the light projecting unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 on the measured surface 101 is within a predetermined range. Since the color measurement position for generating color conversion information can be set based on the difference between the two, the light projecting unit 20, the light receiving unit 30, and the measured surface 101 at the color measurement position for generating color conversion information. The relative position of the above can be made as close as possible to the reference position to improve the color measurement accuracy, and the central axis of the light beam emitted from the light projecting unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 match. It is not necessary to measure the color until the color is measured, the number of times the color is measured can be reduced, and the time required for the color measurement can be shortened.

In the above-mentioned example, the reference position is a position where the central axis of the light flux from the light projecting unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 coincide with each other on the measured surface 101A of the recording sheet 100A as a reference. Therefore, the third is calculated from the difference α of the irradiation angle of the light projecting unit 20 at the first relative position where the highest brightness with respect to the irradiation angle of the reference light projecting unit 20 is measured, or the difference α of the irradiation angle. From the difference α'between the reference height h0 in the direction Z and the height h5 of the first color measurement position, the thickness of the color-measured recording sheet 100 (for example, the thickness + height difference α of the reference recording sheet 100A). ′) Can also be calculated. By grasping the thickness of the recording sheet 100 to be color-measured in this way, a sensor or the like for measuring the thickness of the recording sheet 100 is not required separately, the cost can be reduced, and the space for arranging the sensors can be reduced. It is also unnecessary and can be miniaturized. Further, by acquiring the thickness of the recording sheet 100, the paper gap, which is the distance between the recording sheet 100 and the recording head 1, can be controlled with high accuracy by the changing unit 40. Therefore, high-precision printing can be realized.

Further, in the present embodiment, the reference position is the central axis of the light flux from the light projecting unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 on the measured surface 101A of the recording sheet 100A having a reference thickness. Since the positions coincide with each other, when the recording sheet 100 having the same thickness as the recording sheet 100A having the reference thickness is used, the color can be measured without adjusting the height. Therefore, the color measurement time can be shortened.

Further, in the above-mentioned example, the reference position coincides with the central axis of the light flux from the light projecting unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 on the measured surface 101A of the recording sheet 100A as a reference. However, the position is not limited to this.

For example, the reference position may be a position where the central axis of the light flux from the light projecting unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 coincide with each other on the support surface 8a of the support member 8. This also makes it possible to calculate the thickness of the recording sheet 100 from the difference α ′ between the reference height h0 in the third direction Z and the height h5 of the first color measurement position.

Further, for example, the reference position may be any position. As described above, the difference α between the irradiation angle of the light projecting unit 20 at an arbitrary reference position and the irradiation angle of the light projecting unit 20 at the relative position (first relative position) where the highest brightness is measured is obtained, and the irradiation angle of this irradiation angle is calculated. The height of the color measuring unit 10 from the measured surface 101 at an arbitrary reference position in the third direction Z from the difference α and the height of the color measuring unit 10 from the measured surface 101 at the relative position where the highest brightness is measured. The difference α'from h5 is calculated, and the color measuring unit 10 is moved to the third direction Z by the distance obtained by adding the difference between the height of the color measuring unit 10 at an arbitrary reference position and the reference height h0 to the difference α'. By moving and performing color measurement in the moved state, color measurement can always be performed at the same height h0 as the reference height h0. Therefore, it is possible to suppress the variation in the height of the color measuring unit 10 from the measured surface 101 at the color measuring position for generating the color conversion information due to the variation in the thickness of the recording sheet 100, and it is possible to suppress the variation. Highly accurate color measurement can be performed by arranging the relative positions of the light unit 20, the light receiving unit 30, and the surface to be measured 101 at reference positions.

Further, in the above-mentioned example, the reference position is the second color measurement position, which is the second relative position, but the present invention is not particularly limited to this, and the reference position and the second relative position may be different. good.

As described above, in the present embodiment, the recording head 1 which is an example of the liquid injection head for injecting liquid ink onto the recording sheet 100 which is a medium and the measured surface 101 of the recording sheet 100 are irradiated with light. A color measurement unit 20 includes a light projecting unit 20 and a light receiving unit 30 that receives light emitted from the light projecting unit 20 and reflected by the measured surface 101 of the recording sheet 100, and measures the color of the measured surface 101 of the recording sheet 100. In a method of driving a liquid injection device including the unit 10, the light projecting unit 20, the light receiving unit 30, and the recording sheet 100 are set to the first relative positions, and the light emitting unit 20 irradiates the recording sheet 100. The light reflected by the surface to be measured 101 is received by the light receiving unit 30, the first color measurement value including the value indicating the brightness of the surface to be measured 101 of the recording sheet 100 is measured, and the light projecting unit 20 and the light receiving unit 30 are measured. And the recording sheet 100 are set to a second relative position different from the first relative position, and the light emitted from the light projecting unit 20 and reflected by the measured surface 101 of the recording sheet 100 is received by the light receiving unit 30. When the lightness of the second colorimetric value indicating the lightness of the measured surface 101 of the recording sheet 100 is measured and the lightness of the first colorimetric value is higher than the lightness of the second colorimetric value, the first color is measured. The recording sheet 100 in which the relative positions of the light emitting unit 20, the light receiving unit 30, and the recording sheet 100 are set as the color measurement positions based on the difference between the relative positions and the preset reference relative positions, and the colors are measured at the color measurement positions. The print data is color-converted by the color conversion information based on the color of the light or the color measurement value of the patch printed on the recording sheet 100. Thus, when the first colorimetric value at the first relative position has a higher brightness than the second colorimetric value at the second relative position, the difference between the first relative position and the reference relative position Based on this, the light projecting unit 20, the light receiving unit 30, and the surface to be measured 101 of the recording sheet (medium) 100 are set to color measurement positions that have the same color measurement conditions as the reference relative positions, and color measurement is performed. Therefore, even if the thickness of the recording sheet 100 varies, the color measurement condition, particularly the height of the color measurement unit 10 from the measured surface 101, can always be measured under the same condition at the color measurement position. Therefore, highly accurate color measurement can be performed.

Further, in the present embodiment, since the color measurement may be performed at at least two relative positions of the first relative position and the second relative position, the color measurement time can be shortened.

Further, in the present embodiment, the first relative position and the second relative position are angles of the central axis of the light beam emitted from the light projecting unit 20 with respect to the third direction Z which is the normal line of the measured surface 101. Is preferably different. As a result, the reflected position of the reflected light on the measured surface 101 of the recording sheet 100 can be changed to perform highly accurate color measurement.

Further, in the present embodiment, when the brightness of the first colorimetric value is higher than the brightness of the second colorimetric value, the light projecting unit 20 with respect to the normal of the measured surface 101 at the first relative position. Distance calculated from the difference between the angle of the central axis of the luminous flux emitted from and the angle of the central axis of the luminous flux emitted from the light projecting unit 20 with respect to the normal of the measured surface 101 at the preset reference relative position. However, it is preferable to move the color measuring unit 10 in the third direction Z, which is the normal direction of the surface to be measured 101. According to this, even if the thickness of the recording sheet 100 varies, the height of the color measuring unit 10 from the measured surface 101 can always be measured under the same conditions, so that highly accurate color measurement can be performed. It can be carried out.

Further, the first relative position is preferably the relative position in which the higher brightness is measured among the plurality of relative positions of the light projecting unit 20, the light receiving unit 30, and the recording sheet 100. According to this, the color conversion information is based on the difference between the relative position and the reference position where the distance between the central axis of the light beam emitted from the light projecting unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 is as short as possible. Since it is possible to set the color measurement position for generating the It is possible to measure colors with high brightness by bringing them closer, and it is possible to improve the color measurement accuracy.

Further, the first relative position is preferably the relative position where the highest brightness is measured among the plurality of relative positions of the light emitting unit 20, the light receiving unit 30, and the recording sheet 100. According to this, the color conversion information is based on the difference between the relative position and the reference position where the distance between the central axis of the light beam emitted from the light projecting unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 is as short as possible. Since it is possible to set the color measurement position for generating the It is possible to measure colors with high brightness by bringing them closer, and it is possible to improve the color measurement accuracy.

(Other embodiments)
Although each embodiment of the present invention has been described above, the basic configuration of the present invention is not limited to the above.

For example, in each of the above-described embodiments, the central axis of the light beam emitted from the light projecting unit 20 is tilted at 45 degrees with respect to the third direction Z (normal direction of the surface to be measured 101). Not limited to this, for example, the central axis of the light beam emitted from the light projecting unit 20 is set along the third direction Z (normal direction of the surface to be measured 101), and the light receiving angle (light receiving light) of the light receiving unit 30 is set. The optical axis of the optical system 31) may be tilted at 45 degrees toward the light projecting unit 20 with respect to the third direction Z (normal direction of the surface to be measured 101). Even in this case, the light corresponding to the central axis of the light beam emitted from the light projecting unit 20 is diffusely reflected by the surface to be measured 101, and the reflected light is aligned with the optical axis of the light receiving optical system 31 of the light receiving unit 30. This makes it possible to increase the brightness and improve the measurement accuracy.

Further, in the above-mentioned inkjet recording device I, an example is described in which the recording head 1 is mounted on the carriage 3 and moves in the second direction Y, but the present invention is not particularly limited to this, and for example, the recording head 1 is the device main body. The present invention can also be applied to a so-called line-type recording device, which is fixed to 4 and prints only by moving a recording sheet 100 such as paper in the first direction X. However, when the color measuring unit 10 is provided in the line type recording device, the color measuring unit 10 may be mounted on the carriage for the color measuring unit provided so as to be movable in the second direction Y.

Further, in each of the above-described embodiments, the color measuring unit 10 is mounted on the carriage 3 so as to move in the second direction Y, but the present invention is not particularly limited to this, and for example, a plurality of color measuring units 10 are measured. If the patches to be colored are arranged side by side in the second direction Y, the color measuring unit 10 does not have to move in the second direction Y. Further, the light receiving elements 32 of the light receiving unit 30 may be arranged side by side in the second direction Y.

Further, for example, when a transparent material is used as the recording sheet 100, the surface 101 to be measured may be reflected by using the portion on which the ink droplet is landed. That is, since the transparent material transmits light, it will be reflected on the surface of the support member 8 unless it is reflected at the portion where the ink droplet is landed. In the present invention, measuring the color of the surface to be measured 101 includes the case of directly measuring the surface of the recording sheet 100 and the case of measuring the color of ink droplets (patches) printed on the surface to be measured 101. Is done.

Further, when the height of the third direction Z from the measured surface 101 of the color measuring unit 10 is changed and the color is measured as in the above-described embodiments 5 and 6, the measured surface 101 of the color measuring unit 10 is used. Since the optics on the recording sheet 100 of the light emitted from the light projecting unit 20 fluctuate as the height of the light is changed, the position of the central axis of the light flux emitted from the light emitting unit 20 on the recording sheet 100 receives light. The value of the brightness measured at a relative position away from the position of the optical axis of the light receiving optical system 31 of the unit 30 is the central axis of the light flux emitted from the light projecting unit 20 on the recording sheet 100 and the light receiving unit 30. It may be greater than or equal to the value of brightness measured at a relative position where the optical axis of the light receiving optical system 31 substantially coincides. However, in the seventh and eighth embodiments, color measurement is performed at the first color measurement position and the second color measurement position without changing the height of the third direction Z from the recording sheet 100 of the color measurement unit 10. Therefore, the height of the color measuring unit 10 from the measured surface 101 fluctuates between the first color measuring position and the second color measuring position, so that the recording sheet 100 (support surface 8a) of the light beam emitted from the light projecting unit 20 is emitted. ) It is possible to suppress fluctuations in the illuminance above. Therefore, in the seventh and eighth embodiments, the color measurement position and the relative position serving as the reference position can be specified with higher accuracy than those of the fifth and sixth embodiments, and the color measurement position for generating the color conversion information is set. And the thickness of the recording sheet 100 can be detected.

Further, in the above-described embodiments 5 and 6, the relative position where the high-brightness color measurement data is measured by changing the height of the third direction Z from the measured surface 101 of the color measurement unit 10 is used as the color conversion information. As the thickness of the recording sheet 100 is detected as it is, the difference between the reference position and the relative value is only detected as the color measurement position for generating the above. Based on the difference between the relative position where the color data is measured and the reference position, the light projecting unit 20, the light receiving unit 30, and the surface to be measured 101 are moved to the color measurement position for generating color conversion information, or the relative position. Compared to converting the thickness of the recording sheet 100 from the difference between the position and the reference position, the color measurement and the thickness of the recording sheet 100 are detected by a simple structure and a simple method, and the surface to be measured of the color measuring unit 10 is measured. It is possible to improve the color measurement accuracy by suppressing the deterioration of the color measurement accuracy for generating the color conversion information due to the height variation from 101.

Further, in the above embodiment, the height of the color measuring unit 10 from the measured surface 101 (support surface 8a) on the measured surface 101 is the reference height, and the distance between the light emitting unit 20 and the light receiving unit 30 is the reference height. Is the reference interval, and the angle of the central axis of the luminous flux emitted from the light projecting unit 20 with respect to the normal line of the measured surface 101 (support surface 8a) and the optical axis of the light receiving optical system 31 of the light receiving unit 30 is the reference. The relative position of the reference, which is an angle and the central axis of the light flux emitted from the light projecting unit 20 and the optical axis of the light receiving optical system 31 of the light receiving unit 30 coincide with each other on the measured surface 101 (support surface 8a), is The arrangement position can satisfy the regulations regarding color measurement in JIS, ASTM, ISO and CIE.

Further, the present invention is intended for a liquid injection device having a wide range of liquid injection heads, for example, a recording head such as various inkjet recording heads used in an image recording device such as a printer, and a color of a liquid crystal display or the like. Liquid injection device using color material injection head used for manufacturing filters, organic EL display, electrode material injection head used for electrode formation such as FED (field emission display), bioorganic material injection head used for biochip manufacturing, etc. It can also be used for.

I ... Inkjet recording device (liquid injection device), 1 ... Inkjet recording head (liquid injection head), 2 ... Ink cartridge, 3 ... Carriage, 4 ... Device body, 5 ... Carriage shaft, 5a ... Transmission gear train, 5b ... Rotating shaft, 5c ... Transmission gear, 5d ... Shift cam, 5e ... Cam follower, 6 ... Drive motor, 7 ... Timing belt, 8 ... Support member, 8a ... Support surface, 9a ... First transport means, 9b ... Second transport Means, 10 ... color measuring unit, 20 ... light projecting unit, 21 ... light source, 22 ... light source optical system, 30 ... light receiving unit, 31 ... light receiving optical system, 32 ... light receiving element, 40 ... changing unit, 41, 41A ... Light source holding unit, 42, 42A ... Light source driving unit, 100 ... Recording sheet (medium), 101 ... Surface to be measured, 200 ... Control device, 210 ... Control unit, 211 ... Control processing unit, 212 ... Storage Unit, 213 ... Drive signal generation unit, 220 ... Printing mechanism, 221 ... Mechanism, 222 ... Carriage mechanism, 230 ... Color measurement mechanism, 250 ... External device, 300 ... Color measurement unit control unit, 301 ... Color measurement processing unit, 302 ... Change unit control unit, 303 ... Brightness determination unit, 304 ... Color measurement position setting unit, 305 ... Reference position acquisition unit, 306 ... Medium thickness calculation unit

Claims (19)

A liquid injection head that injects liquid into the medium,
It has a light projecting unit that irradiates the measured surface of the medium with light, and a light receiving unit that receives the reflected light obtained by reflecting the light emitted from the light projecting unit on the measured surface of the medium. A color measuring unit that measures the color of the surface to be measured, and
A changing part that changes the reflection position on the medium of light that coincides with the central axis of the light flux emitted from the light emitting part, and a changing part.
The reflection position obtained by measuring the color measurement data having the highest brightness among the color measurement data of the surface to be measured that the light receiving unit receives light at the reflection position changed in the change unit and the color measurement unit measures the color. The control unit to set the color measurement position and
A liquid injection device comprising. The control unit measures the color measuring unit when the light receiving unit receives the light reflected by the surface of the support member that controls the changing unit and supports the surface of the medium opposite to the surface to be measured. The liquid according to claim 1, wherein a position having the highest brightness of the colored color measurement data is set as a reference position, and the thickness of the medium is acquired based on the reference position and the color measurement position. Injection device. The control unit measures the medium based on the thickness of the medium and the color measurement result of the non-landing region where the liquid of the medium is not landed, which is measured by the color measuring unit at the color measuring position. The liquid injection device according to claim 2, wherein the liquid injection device is specified. The aspect according to any one of claims 1 to 3, wherein the changing part changes the distance between the color measuring part and the medium in the normal direction of the surface to be measured of the medium. Liquid injection device. A liquid injection head that injects liquid into the medium,
It has a light projecting unit that irradiates the measured surface of the medium with light, and a light receiving unit that receives the reflected light obtained by reflecting the light emitted from the light projecting unit on the measured surface of the medium. A color measuring unit that measures the color of the surface to be measured, and
A changing part that changes the reflection position of the light corresponding to the central axis of the light beam emitted from the light emitting part on the measured surface, and a changing part.
The difference between the reflection position measured by the color measurement data having the highest brightness among the color measurement data measured by the color measurement unit at the reflection position changed in the change unit and the preset reference position. A control unit that sets the color measurement position based on
A liquid injection device comprising. The changed part changes the distance between the light emitting part and the light receiving part in the surface direction of the measured surface, or the changed part changes the irradiation angle of the light emitting part with respect to the normal of the measured surface or The liquid injection device according to claim 5, wherein the light receiving angle of the light receiving unit is changed. The liquid injection device according to any one of claims 1 to 6, wherein the color measuring unit is provided on the upstream side of the liquid injection head in the transport direction of the medium. Claims 1 to 7 are characterized in that the liquid injection head and the color measuring unit are mounted on a carriage provided so as to be movable in a transport direction of the medium and a direction orthogonal to the measured surface. The liquid injection device according to any one of the above. The control unit prints with color conversion information based on the color measurement value of the surface to be measured measured by the color measurement unit at the color measurement position or the color measurement value of the patch printed on the surface to be measured. The liquid injection device according to any one of claims 1 to 8, wherein the data is color-converted. It has a light projecting unit that irradiates the surface to be measured of the medium with light, and a light receiving unit that receives the reflected light obtained by reflecting the light emitted from the light projecting unit on the surface to be measured of the medium. Equipped with a color measuring unit that measures the color of the surface to be measured,
The reflected position of the light corresponding to the central axis of the light beam emitted from the light projecting portion on the medium is changed, the reflected light is received by the light receiving portion, the color to be measured is measured, and the modified surface is measured. Among the reflection positions, the reflection position having the highest brightness of the surface to be measured, which is received by the light receiving unit and the color measured by the color measuring unit, is set as the color measuring position, and the color is measured by the color measuring unit. Color measurement method. A liquid injection head that injects liquid into the medium,
The surface to be measured of the medium is provided with a light projecting unit that irradiates the surface to be measured of the medium with light and a light receiving unit that receives light that is emitted from the light projecting unit and reflected by the surface of the medium to be measured. The color measuring part that measures the color and
It is a driving method of a liquid injection device provided with
The light emitting section, the light receiving section, and the medium are set to first relative positions, and the light received from the light projecting section and reflected by the measured surface of the medium is received by the light receiving section, and the medium is received. The first color measurement value including the value indicating the brightness of the surface to be measured is measured, and the color is measured.
The light projecting unit, the light receiving unit, and the medium are set to a second relative position different from the first relative position, and the light emitted from the light projecting unit and reflected by the measured surface of the medium is emitted. Light is received by the light receiving unit, and a second color measurement value indicating the brightness of the surface to be measured of the medium is measured.
When the brightness of the first color measurement value is higher than the brightness of the second color measurement value, the first relative position is set as the color measurement position.
A method for driving a liquid injection device, characterized in that print data is color-converted by color conversion information based on the color of the medium measured at the color measurement position or the color conversion value of a patch printed on the medium. The light emitting unit, the light receiving unit, and the medium are included in the first relative position and the second relative position, and the relative positions of the light emitting unit, the light receiving unit, and the medium are different from each other at three locations. Set to the above multiple relative positions,
At each of the plurality of relative positions, the light receiving portion receives the light emitted from the light projecting portion and reflected by the measured surface of the medium, and a color measurement value indicating the brightness of the measured surface of the medium is obtained. The method for driving a liquid injection device according to claim 11, wherein the color is measured. The method for driving a liquid injection device according to claim 12, wherein the brightness of the first color measurement value is the highest brightness among the brightness of the color measurement values measured at the plurality of relative positions. A liquid injection head that injects liquid into the medium,
The surface to be measured of the medium is provided with a light projecting unit that irradiates the surface to be measured of the medium with light and a light receiving unit that receives light that is emitted from the light projecting unit and reflected by the surface of the medium to be measured. The color measuring part that measures the color and
It is a driving method of a liquid injection device provided with
The light emitting section, the light receiving section, and the medium are set to first relative positions, and the light received from the light projecting section and reflected by the measured surface of the medium is received by the light receiving section, and the medium is received. The first color measurement value including the value indicating the brightness of the surface to be measured is measured, and the color is measured.
The light projecting unit, the light receiving unit, and the medium are set to a second relative position different from the first relative position, and the light emitted from the light projecting unit and reflected by the measured surface of the medium is emitted. Light is received by the light receiving unit, and a second color measurement value indicating the brightness of the surface to be measured of the medium is measured.
When the brightness of the first colorimetric value is higher than the brightness of the second colorimetric value, the floodlight unit is based on the difference between the first relative position and the preset reference relative position. And the relative position between the light receiving part and the medium is set as the color measurement position.
A method for driving a liquid injection device, characterized in that print data is color-converted by color conversion information based on the color of the medium measured at the color measurement position or the color conversion value of a patch printed on the medium. The first relative position and the second relative position are characterized in that the distance between the light emitting portion and the light receiving portion in a direction intersecting the normal direction of the measured surface of the medium is different. The method for driving a liquid injection device according to claim 14. When the brightness of the first colorimetric value is higher than the brightness of the second colorimetric value, the distance between the light projecting unit and the light receiving unit at the first relative position is set in advance. The claim is characterized in that the color measuring unit is moved in the normal direction of the surface to be measured by a distance calculated from the difference between the distance between the light emitting unit and the light receiving unit at a reference relative position. 15. The method for driving a liquid injection device according to 15. 14. The first relative position and the second relative position are characterized in that the angle of the central axis of the light flux emitted from the light projecting portion with respect to the normal of the surface to be measured is different from that of claim 14. How to drive a liquid injection device. When the brightness of the first colorimetric value is higher than the brightness of the second colorimetric value, it is irradiated from the light projecting portion with respect to the normal of the surface to be measured at the first relative position. Only the distance calculated from the difference between the angle of the central axis of the light beam and the angle of the central axis of the light beam emitted from the light projecting portion with respect to the normal of the surface to be measured at the preset reference relative position, said. The method for driving a liquid injection device according to claim 17, wherein the color measuring unit is moved in the normal direction of the surface to be measured. The light projecting portion, the light receiving portion, and the support member supporting the surface of the medium opposite to the surface to be measured are set at a third relative position, and the medium is irradiated from the light projecting portion and is irradiated from the support member. The light reflected by the support surface supporting the support member is received by the light receiving unit, and a third color measurement value including a value indicating the brightness of the support surface of the support member is measured.
The light projecting portion, the light receiving portion, and the support member are set to a fourth relative position different from the third relative position, and the light emitted from the floodlight portion and reflected by the support surface of the support member. Is received by the light receiving unit, and a fourth color measurement value indicating the brightness of the support surface of the support member is measured.
When the brightness of the third colorimetric value is higher than the brightness of the fourth colorimetric value, the third relative position is set as the reference position.
The method for driving a liquid injection device according to any one of claims 11 to 18, wherein the thickness of the medium is detected from the difference between the color measurement position and the reference position.

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