JP6984400B2 - Spectral measuring device, electronic equipment and spectroscopic measuring method - Google Patents

Description

The present invention relates to a spectroscopic measuring device, an electronic device and a spectroscopic measuring method.

Conventionally, an analyzer for measuring the optical characteristics of each wavelength of incident light is known (see, for example, Patent Document 1).

In the spectroscopic measuring instrument of Patent Document 1, the object is irradiated with light from the light source unit, and the light reflected by the inspection object is separated into a plurality of measurement wavelengths to generate a measurement spectrum. Then, by applying a transformation matrix whose spectrum is determined from known light to the obtained measurement spectrum, the spectrum of the object can be estimated with high accuracy.

Japanese Unexamined Patent Publication No. 2013-142656

By the way, a device as described above may be provided in a printing device and used as a color measuring device for measuring the color of an object printed on a medium. When measuring the color of an object, it is necessary to measure the reflectance of the object, but when measuring the reflectance, a reference plate is usually used for calibration. In the apparatus described in Patent Document 1, as described above, the spectrum of the object can be estimated from the measurement spectrum, but in order to calculate the reflectance of the object from the estimated spectrum, it is configured with a reference color (for example, white). It is necessary to measure the reference plate (white plate) that has been used.
However, in order to carry out high-precision measurement, it is necessary to match the conditions when measuring the color of the reference object (for example, the reference plate) and when measuring the color of the object formed on the medium. Therefore, it is necessary to arrange the reference object at the same height as the media, and it is necessary to secure the arrangement position of the reference object. That is, the degree of freedom in the placement position of the reference object was reduced.

One of the objects of the present invention is to provide a spectroscopic measuring device, an electronic device, and a spectroscopic measuring method capable of increasing the degree of freedom in the arrangement position of a reference object.

The spectroscopic measuring device according to one application example of the present invention measures the reflectance of the object based on a spectroscope that measures the amount of light from the object for a plurality of wavelengths and the measurement result of the amount of light for the plurality of wavelengths. The calculation unit includes a calculation unit for calculation, and the calculation unit is characterized in that a conversion matrix for converting the measurement result into a reflectance is applied to the measurement result to calculate the reflectance of the object.

In this application example, the arithmetic unit applies a transformation matrix that converts the measured value into a reflectance on the measured value measured by the spectroscope, and calculates the reflectance of the object. That is, the reflectance is calculated directly from the measured value measured by the spectroscope. Therefore, when calculating the reflectance of an object, it is not necessary to measure the reflectance of the reference color using a reference object (for example, a reference plate), and the conditions at the time of color measurement are made uniform between the reference object and the object. There is no need. Therefore, it is not necessary to arrange the reference object at the same height as the object, and the degree of freedom in arranging the reference object can be increased.

In the spectroscopic measuring apparatus of this application example, the conversion matrix has the reflectance for k (k is a natural number) wavelengths of a sample whose reflectance is known, and m (m) when the sample is measured by the spectroscope. Is a natural number), and it is preferable that the matrix is calculated by using the measurement results for the wavelengths.
In this application example, the transformation matrix is calculated from the reflectance for k wavelengths of a sample whose reflectance is known and the measurement result for m wavelengths when the sample is measured by a spectroscope. Therefore, the transformation matrix can be calculated by measuring a sample having a known reflectance with a spectroscope. That is, if a sample having a known reflectance is prepared, the transformation matrix can be calculated without using a special device. Therefore, the transformation matrix for directly calculating the reflectance from the measured value measured by the spectroscope can be easily calculated.

In the spectroscopic measurement apparatus of this application example, the known reflectance matrices for the k wavelengths in each of the n (n is a natural number) samples having different colors are _{defined as Sn} and k, and the spectroscope is used. In each of the n measured samples, the matrix of the measurement results of the amount of light for the m wavelengths is Dn _{, m} , the transformation matrix is Ms, and the evaluation function F (Ms) is F (Ms). = | _{Sn, k} −Ms · Dn _{, m} | ² , the transformation matrix Ms is preferably a matrix having the minimum evaluation function F (Ms).
In this application example, the transformation matrix Ms is a matrix in which the evaluation function F (Ms) derived from _{the reflectance matrix Sn, k} and the measurement result matrix Dn _{, m is minimized.} That is, the transformation matrix Ms is a matrix in which Sn _{, k} and Ms · Dn _{, m} match. Therefore, the transformation matrix Ms can be determined by expanding the evaluation function F (Ms) in the same manner as a general least squares error solution. Therefore, the transformation matrix Ms for directly calculating the reflectance from the measured value measured by the spectroscope can be easily determined.

In the spectroscopic measuring apparatus of this application example, the matrix of known reflectances for the k wavelengths in each of the n samples having different colors is _{Sn and k,} and the n is measured by the spectroscope. In each of the samples, the matrix of the measurement results of the amount of light for the m wavelengths is Dn _{, m} , the transformation matrix is Ms, and the transformation matrix Ms has a multiplier term of β · Ms ^T · Ms. , The evaluation function F (Ms) is F (Ms) = | _{Sn, k} −Ms · D _{n, m} | ² + β · Ms ^T · Ms, and the transformation matrix Ms has the smallest evaluation function F (Ms). It is preferable that the matrix is.
Here, β is a constant called a hyperparameter, and T displayed on the right shoulder of the transformation matrix Ms indicates that it is a transposed matrix.
In this application example, the addition of βMs T ^Ms is number term to multiply the evaluation function F (Ms), it can be calculated a transformation matrix that suppresses overfitting.
That is, in the evaluation function F (Ms), when such a multiplier term is not added, the best linear unbiased estimator is performed under the condition that the _{matrix Sn, k} and the matrix Dn _{, m do not include an error.} It is possible to calculate the transformation matrix Ms that can calculate the reflectance as an estimator. However, if an _{error is included in the matrix Sn, m} or the matrix Dn _{, m} , it becomes a parameter of the overfitting state depending on the degree. In this case, the parameters of the transformation matrix Ms determined by expanding this evaluation function F (Ms) are obtained as a state in which very large values and small values are mixed, and the variation of the parameters becomes large. .. In this case, when calculating the reflectance by applying a conversion matrix to the measured value of the measurement result by the spectroscope, if the measured value of the measurement result is a measured value containing an error similar to that at the time of calculating the conversion matrix. Although it is possible to obtain the reflectance with high accuracy, the estimation accuracy of the reflectance may decrease depending on the degree and variation of the error included in the measured value of the measurement result (overfitting).
In contrast, in the present application example, as described above, evaluation by adding βMs T ^Ms is number term to multiply the function F (Ms), the dispersion of the parameters of the transformation matrix Ms (or Euclidean norm) Minimize It is possible to make it regular by adding a constraint term. As a result, the variation in the parameters of the transformation matrix Ms can be reduced, and the transformation matrix that can suppress overfitting can be calculated. That is, when the measured value of the measurement result is converted into the reflectance by using the transformation matrix Ms, the reflectance can be calculated with high accuracy even if the error included in the measured value varies.

In the spectroscopic measuring apparatus of this application example, the arithmetic unit uses the measurement results for m wavelengths when a sample whose reflectance is known by the spectroscope is measured, and the reflectances of k wavelengths of the sample. It is preferable to calculate the conversion matrix using.
In this application example, the arithmetic unit calculates a transformation matrix from the measurement result of a sample whose reflectance is known and the reflectance of the sample. As a result, the spectroscopic measuring device provided with such a calculation unit can calculate a transformation matrix for directly calculating the reflectance from the measured value measured by the spectroscope if a sample having a known reflectance is prepared. Can be done. Therefore, for example, when the light source or the like changes over time due to the use of the spectroscopic measuring device for a long time, the transformation matrix in that state can be calculated, and the reflectance of the object can be calculated accurately.

In the spectroscopic measuring apparatus of this application example, a reference object is further provided, and the calculation unit is based on the measurement result of the reference object by the spectroscope when the reference object is irradiated with light from a light source. It is preferable to correct the measurement result when the object is measured.
In this application example, the calculation unit corrects the measurement result of the object based on the measurement result for the reference object (for example, the reference plate). As a result, for example, even if the light amount of the light source of the spectroscope changes, the measurement result of the object is corrected based on the measurement result of the reference object measured in the state where the light amount of the light source changes. Can be eliminated. Therefore, the reflectance of the object can be calculated accurately.

The spectroscopic measuring device of the present application further includes a temperature measuring unit for measuring the temperature of the spectroscope, and the arithmetic unit uses the spectroscope to measure the object based on the temperature measured by the temperature measuring unit. It is preferable to correct the measurement result at the time of measurement.
In this application example, the calculation unit corrects the measurement result of the object based on the temperature measured by the temperature measurement unit. As a result, for example, even if the characteristics of the spectroscopic device of the spectroscope change due to temperature changes, if the relationship between the characteristics of the spectroscopic device and the temperature is obtained in advance, the change in the characteristics will be caused by the measured temperature. Can be grasped. Therefore, it is possible to make corrections according to the change in the characteristics, and it is possible to calculate the reflectance of the object with high accuracy.

An electronic device according to an application example of the present invention is characterized by including a spectroscopic measuring device as described above and a control unit for controlling the calculation unit.
Since the spectroscopic measuring device described above is provided in this application example, it is necessary to measure the reference color using a reference object (for example, a reference plate) when calculating the reflectance from the measured value measured by the spectroscope. There is no. As a result, it is not necessary to match the conditions for color measurement between the reference object and the object. Therefore, it is not necessary to arrange the reference object at the same height as the object, and the degree of freedom in arranging the reference object can be increased.

In the spectroscopic measurement method according to one application example of the present invention, a spectroscope measures the amount of light from an object for a plurality of wavelengths, and a calculation unit converts the measurement result of the amount of light for the plurality of wavelengths into a reflectance. It is characterized in that the matrix is applied to the measurement result to calculate the reflectance of the object.
In this application example, the same effect as that of the spectroscopic measuring device can be obtained, and it is not necessary to arrange the reference object (for example, the reference plate) at the same height as the object, and the degree of freedom in arranging the reference object is high. Can be raised.

The external view which shows the schematic structure of the printer of 1st Embodiment. The block diagram which shows the schematic structure of the printer of 1st Embodiment. The plan view which shows the schematic structure of the carriage of 1st Embodiment. The cross-sectional view which shows the schematic structure of the spectroscope of 1st Embodiment. The cross-sectional view which shows the schematic structure of the carriage of 1st Embodiment. The block diagram which showed the functional structure of the CPU of the printer of 1st Embodiment. The flowchart which shows the transformation matrix calculation process in the printer of 1st Embodiment. The flowchart which shows an example of the correction process in the printer of 1st Embodiment. The flowchart which shows the reference plate measurement process in the printer of 1st Embodiment. The flowchart which shows the reflectance calculation processing in the printer of 1st Embodiment. The graph which shows the correlation between the initial value of the received light amount and the measured value at the time of the measurement processing of the reference plate in the printer of 1st Embodiment. The graph which shows the inclination of the measured value with respect to the initial value of the received light amount at the time of the measurement processing of the reference plate in the printer of 1st Embodiment.

[First Embodiment]
Hereinafter, the first embodiment according to the present invention will be described with reference to the drawings. In the present embodiment, as an example of the electronic device of the present invention, a printer 1 (inkjet printer) provided with a spectroscopic measuring device will be described below.

[Outline configuration of printer]
FIG. 1 is a perspective view showing a configuration example of the appearance of the printer 1 of the present embodiment. FIG. 2 is a block diagram showing a schematic configuration of the printer 1 of the present embodiment. FIG. 3 is a plan view showing a schematic configuration of the carriage 13 of the printer 1 of the present embodiment.
As shown in FIG. 1, the printer 1 corresponds to the electronic device of the present invention, and the unit housing 10, the supply unit 11, the transport unit 12, the carriage 13, the carriage moving unit 14, and the control of the present invention. It includes a control unit 15 (see FIG. 2) corresponding to the unit and a maintenance unit 20. Further, as shown in FIG. 3, the carriage 13 is provided with a printing unit 16, a spectroscope 17, and a shutter mechanism 19 for protecting the spectroscope 17 from foreign matter such as ink mist.

The printer 1 configured in this way controls each unit 11, 12, 14 and the carriage 13 based on print data input from an external device 30 such as a personal computer, and prints an image on the media M. .. As this image, for example, a correction pattern for correcting density unevenness can be used. The printer 1 measures the color of the correction pattern by the spectroscope 17, and performs various correction processes such as color shift correction based on the color measurement result of the correction pattern.
Hereinafter, each configuration of the printer 1 will be specifically described.

The unit housing 10 is provided with units 11, 12, 14, 15, 20 and a carriage 13. The unit housing 10 is located on the + Z side, and has a bottom surface portion 101 on which the transport unit 12, maintenance unit 20, and the like are arranged, and a first side surface portion 102 and a second side surface portion 103 that rise from the bottom surface portion 101 in the −Z direction. , And a back surface portion 104. The first side surface portion 102 is located on the −X side, the second side surface portion 103 is located on the + X side, and the back surface portion 104 is located between the first side surface portion 102 and the second side surface portion 103 along the X direction. To position.
Here, the first side surface portion 102 is a surface with which the first end portion 194 of the shutter mechanism 19, which will be described later, abuts, and the second side surface portion 103 is a surface with which the second end portion 195 of the shutter mechanism 19 abuts. .. Although not shown, the printer 1 includes an outer housing that covers at least a part of the unit housing 10.

The supply unit 11 is a unit that supplies the media M (in the present embodiment, the paper surface is exemplified), which is the object of the present invention, to the image forming position. The supply unit 11 includes, for example, a roll body 111 (see FIG. 1) around which the media M is wound, a roll drive motor (not shown), a roll drive train wheel (not shown), and the like. Then, based on the command from the control unit 15, the roll drive motor is rotationally driven, and the rotational force of the roll drive motor is transmitted to the roll body 111 via the roll drive train wheel train. As a result, the roll body 111 rotates, and the paper wound around the roll body 111 is supplied to the downstream side (+ Y direction) in the Y direction (sub-scanning direction).
In this embodiment, an example of supplying the paper wrapped around the roll 111 is shown, but the present invention is not limited to this. For example, the media M may be supplied by any supply method, for example, the media M such as paper loaded on the tray or the like is supplied one by one by a roller or the like.

The transport unit 12 transports the media M supplied from the supply unit 11 along the Y direction. The transport unit 12 includes a driven roller (not shown) which is arranged at a position where the media M is sandwiched between the transport roller 121 and the transport roller 121 and which follows the transport roller 121, and a platen 122.
The transfer roller 121 is transmitted with a driving force from a transfer motor (not shown), and when the transfer motor is driven by the control of the control unit 15, it is rotationally driven by the rotational force to move the media M between the transfer roller 121 and the driven roller. It is conveyed along the Y direction while being sandwiched. Further, a platen 122 facing the carriage 13 is provided on the downstream side (+ Y side) of the transport roller 121 in the Y direction.

The carriage 13 is a housing including a printing unit 16 that ejects ink to the media M to print an image, a spectroscope 17 that spectroscopically measures the color of the image on the media M, and a shutter mechanism 19. ..
The carriage 13 is moved along the main scanning direction (X direction) by the carriage moving unit 14. The detailed configuration of the carriage 13, the printing unit 16, the spectroscope 17, and the shutter mechanism 19 will be described later.
In the following description, the −X side in the main scanning direction (X direction) may be referred to as the Home side, and the + X side may be referred to as the Full side. Here, Home is a position where the carriage 13 is retracted to a standby state in which printing processing is not performed. Also, Full is on the opposite side of Home.

The carriage moving unit 14 reciprocates the carriage 13 along the X direction based on a command from the control unit 15.
The carriage moving unit 14, for example, includes a carriage guide shaft 141, a carriage motor 142, and a timing belt 143, as shown in FIG.
The carriage guide shaft 141 is arranged along the X direction, and both ends thereof are fixed to, for example, a housing of the printer 1. The carriage motor 142 drives the timing belt 143. The timing belt 143 is supported substantially parallel to the carriage guide shaft 141, and a part of the carriage 13 is fixed. Then, when the carriage motor 142 is driven based on the command of the control unit 15, the timing belt 143 moves in the forward and reverse directions, and the carriage 13 fixed to the timing belt 143 is guided by the carriage guide shaft 141 and reciprocates.

The maintenance unit 20 is used when performing maintenance of the nozzle unit 161 (see FIG. 3) included in the printing unit 16 which will be described later. As shown in FIGS. 1 and 3, the maintenance unit 20 is provided at the Home position of the printer 1. The printer 1 includes a cap, a suction pump, and the like (not shown) that suck ink from the nozzle included in the nozzle unit 161 after moving the carriage 13 to the Home position during maintenance.

As shown in FIG. 2, the control unit 15 includes an I / F 151, a unit control circuit 152, a memory 153, and a CPU (Central Processing Unit) 154.
The I / F 151 inputs the print data input from the external device 30 to the CPU 154.
The unit control circuit 152 includes a control circuit for controlling the supply unit 11, the transfer unit 12, the carriage moving unit 14, the maintenance unit 20, the printing unit 16, and the spectroscope 17, respectively, based on a command signal from the CPU 154. , Control the operation of each unit. The control circuit of each unit may be provided separately from the control unit 15 and connected to the control unit 15.

The memory 153 stores various programs and various data that control the operation of the printer 1. Examples of various data include print profile data in which the ejection amount of each ink with respect to the color data included as print data is stored. Further, the emission characteristics for each wavelength of the light source 179, which will be described later, and the spectral characteristics depending on the temperature of the spectroscopic device 173A may be stored.

The CPU 154 reads and executes various programs stored in the memory 153 to control the drive of the supply unit 11, the transfer unit 12, and the carriage movement unit 14, the print control of the printing unit 16, the measurement control of the spectroscope 17, and the measurement control of the spectroscope 17. , Arithmetic processing and correction processing (for example, correction processing of density unevenness and correction processing of color shift) based on the measurement result of the spectroscope 17 are performed. The specific function of the CPU 154 will be described later.

[Carriage configuration]
Next, the configuration of the carriage 13, the printing unit 16, the spectroscope 17, and the shutter mechanism 19 provided on the carriage 13 will be described.
As shown in FIG. 3, the carriage 13 is a housing on which the printing unit 16, the spectroscope 17, and the shutter mechanism 19 are mounted, and is moved along the main scanning direction (X direction) by the carriage moving unit 14. Possible to be configured. Of these, the printing unit 16 and the spectroscope 17 are connected to the control unit 15 by a flexible circuit 130 (see FIG. 1), and are driven from the control unit 15 based on a control signal.
Further, as will be described in detail later, the shutter 192 included in the shutter mechanism 19 closes the window portion 176A (see FIG. 4) of the spectroscope 17 in response to the movement of the carriage 13 along the X direction, and the window portion. The state in which the 176A is open (the state in which light can be incident on the spectroscope 17) and the state in which the light is open can be changed.

[Structure of printing section]
Based on the command signal from the control unit 15, the printing unit 16 individually ejects ink onto the media M at a portion facing the media M to form an image on the media M (relative to the media M). Image formation processing) is performed.
As shown in FIG. 3, the printing unit 16 includes a nozzle unit 161 corresponding to inks of a plurality of colors, an ink cartridge (not shown) for supplying ink to each nozzle unit 161 and ink from the ink cartridge to the nozzle unit 161. It is configured to include a supply pipe (not shown) for supplying the ink.
The nozzle unit 161 is provided for each color discharged to the media M (for example, cyan, magenta, yellow, light cyan, light magenta, gray, light gray, matte black, photo black, etc.). These nozzle units 161 are provided with nozzles (not shown) for ejecting ink droplets. For example, a piezo element is arranged in these nozzles, and by driving the piezo element, ink droplets supplied from the ink tank are ejected to the + Z side and land on the media M to form dots.

[Spectroscope configuration]
FIG. 4 is a cross-sectional view showing a schematic configuration of the spectroscope 17. Note that FIG. 4 shows the configuration of the spectroscope 17 in a state where the window portion 176A is open (a state in which the shutter 192 is moved to a position (open position) away from the window portion 176A).
As shown in FIG. 4, the spectroscope 17 includes a base 171 and a substrate holding portion 172 fixed to the base 171 and a spectroscopic device holding substrate 173 and a light receiving element holding substrate 174 held by the substrate holding portion 172. , And a cover portion 175.

The base 171 includes a measurement light introduction unit 176 through which the light reflected at the measurement position of the media M passes, and a light source arrangement unit 177 in which the light source 179 is arranged.
The measurement light introduction portion 176 is, for example, a through hole along the Z direction, and the window portion 176A is arranged at the + Z side end portion. Further, on the −Z side of the measurement light introduction unit 176, an optical holding unit 178 for holding an incident optical system such as an aperture 178A or an incident lens 178B is fixed. The optical axis of the window portion 176A, the aperture 178A, and the incident lens 178B coincides with the measurement optical axis L of the spectroscopic device 173A and the light receiving element 174A described later.

The light source arranging portion 177 has, for example, a cylindrical hole portion 177A that is closer to the measurement optical axis L as the central axis moves toward the + Z side. A light source 179 is arranged on the −Z side of the cylindrical hole portion 177A. As the light source 179, for example, an LED can be exemplified, and by fixing the LED substrate provided with the LED to the −Z side end portion of the tubular hole portion 177A by, for example, screwing, the LED (light source) is attached to the base 171. 179) is fixed. A substrate (LED substrate or the like) holding the light source 179 is connected to a connector 175B described later.
Further, the + Z side end portion of the cylindrical hole portion 177A becomes an illumination window 177B from which the light of the light source 179 is emitted. When the shutter 192 is located in the open position, as shown in FIG. 4, the illumination window 177B is also opened and faces the media M placed on the platen 122. When the light source 179 is emitted in this state, the light of the light source 179 is applied to the measurement position P in a predetermined range centered on the intersection of the media M and the measurement optical axis L. In this embodiment, the spectroscopic measurement is carried out according to the method (45 ° x: 0 °) under the optical geometric conditions defined by the color measurement standard (JIS Z 8722). That is, in the present embodiment, the illumination light from the light source 179 is incident at an incident angle of 45 ° ± 2 ° with respect to the measurement position P, and is reflected by the measurement target at 0 ° ± 10 ° in the normal direction. Is incident on the light receiving element 174A along the measurement optical axis L.

The substrate holding portion 172 is fixed to the base 171 by, for example, screwing. A spectroscopic device holding substrate 173 and a light receiving element holding substrate 174 are fixed to the substrate holding portion 172.
The spectroscopic device holding substrate 173 is a substrate on which the spectroscopic device 173A is held, and has a through hole on the optical axis (measurement optical axis L) of the spectroscopic device 173A. The spectroscopic device holding substrate 173 is fixed to the substrate holding portion 172 at a position on the −Z side of the optical holding portion 178 and at a position where the optical axis of the spectroscopic device 173A coincides with the measurement optical axis L. The spectroscopic device 173A is an optical device that transmits light of a specific wavelength from incident light, and examples thereof include an etalon element, a liquid crystal tunable filter (LCTF), and an acoustic-optical variable wavelength filter (AOTF). .. The spectroscopic device holding substrate 173 is provided with various circuits for controlling the spectroscopic device 173A, and the circuits are connected to the connector 175B. Further, the spectroscopic device holding substrate 173 is provided with a temperature measuring unit 173B (see FIG. 2). The temperature measuring unit 173B is a temperature measuring unit of the present invention, and in the present embodiment, the temperature of the spectroscopic device 173A is measured in the spectroscope 17.

The light receiving element holding substrate 174 is a substrate on which the light receiving element 174A is held. The light receiving element holding substrate 174 is fixed to the substrate holding portion 172 at a position on the −Z side of the spectroscopic device holding substrate 173 and at a position where the optical axis of the light receiving element 174A coincides with the measurement optical axis L. Further, the light receiving element holding substrate 174 includes various circuits for controlling the light receiving element 174A, and the circuits are connected to the connector 175B.
Further, the light receiving element 174A receives the light transmitted through the spectroscopic device 173A in the light receiving region, and outputs a detection signal (current value) according to the amount of light received. The detection signal output by the light receiving element 174A is input to the control unit 15 via an IV converter (not shown), an amplifier (not shown), and an AD converter (not shown).

As shown in FIG. 4, the cover portion 175 is fixed to, for example, the outer peripheral edge of the base 171 and together with the base 171 are a substrate holding portion 172, a spectroscopic device holding substrate 173, a light receiving element holding substrate 174, and an optical holding portion. It forms a closed space (dark space) for accommodating 178.
Further, an opening 175A is provided in a part of the cover portion 175, and a connector 175B is provided in the opening 175A. The connector 175B is electrically connected to the control unit 15 and transmits a control signal from the control unit 15 to the light source 179, the spectroscopic device holding substrate 173, and the light receiving element holding substrate 174.

[Shutter mechanism configuration]
FIG. 5 is a cross-sectional view showing a schematic configuration of a carriage 13 provided with a shutter mechanism 19. FIG. 5 shows a state when the shutter 192 is located at a closed position that closes the window portion 176A.
The shutter mechanism 19 shown in the present embodiment includes a carriage 13, a shutter holding portion 191 having a shutter 192, and a unit housing 10.
Specifically, as shown in FIG. 5, the bottom 131 of the carriage 13 has an opening that allows the reflected light from the media M to enter the spectroscope 17 at a position overlapping the spectroscope 17 (window portion 176A) in the Z direction. The portion 132 is formed. Further, an insertion hole 134 through which the shutter holding portion 191 is inserted is formed on the side surface 133 on the ± X side of the carriage 13. The surface of the insertion hole 134 on the + Z side is a flat surface parallel to the XY plane, and is flush with the upper surface 131A (the surface on the −Z side) of the bottom 131 of the carriage 13.
Further, a positioning mechanism 135 for positioning the shutter holding portion 191 is arranged in at least one of the insertion holes 134 on the ± X side (in this embodiment, the insertion hole 134 on the + X side). The positioning mechanism 135 may include, for example, a locking projection provided in either the insertion hole 134 or the shutter holding portion 191 and an engaging hole provided in the other to engage the locking projection. It can be exemplified.

As shown in FIG. 5, the shutter holding portion 191 is formed in a flat plate shape long in the X direction, for example. A shutter 192 is provided in a part of the shutter holding portion 191, and a light passing portion 193 is provided at a position separated by a distance u on the + X side of the shutter 192.

The shutter 192 is a portion that closes the window portion 176A. The shutter 192 is provided with a reference plate 192A which is a reference object for calculating a correction value of the measurement result of the media M which is an object. In the present embodiment, the reference plate 192A is a white plate having a reflectance of, for example, 99% or more for light of each wavelength in a predetermined wavelength region (for example, visible light region), and the shutter 192 is moved to the closed position. , Is provided at a position facing the window portion 176A.

Further, the shutter 192 is provided with a first wiper 192B in contact with the lower surface of the spectroscope 17 at the end on the + X side. When the shutter 192 moves from the closed position to the open position, the first wiper 192B comes into contact with the lower surface of the window portion 176A when it moves toward the −X side. Similarly, the first wiper 192B comes into contact with the lower surface of the window portion 176A when the shutter 192 moves from the open position to the closed position. By opening and closing the shutter 192 in this way, the window portion 176A can be cleaned by the first wiper 192B.

Further, a second wiper 192C projecting to the + Z side is provided on the −X side of the window portion 176A on the + Z side surface of the spectroscope 17 (base 171) facing the shutter 192. When the shutter 192 moves from the closed position to the open position, the second wiper 192C comes into contact with the reference plate 192A when it moves toward the −X side, and removes stains on the surface of the reference plate 192A due to ink droplets or the like. ..

The light passing portion 193 is a portion that allows the reflected light from the measurement position P to pass through the spectroscope 17. The light passing portion 193 may be configured by, for example, a through hole penetrating the shutter holding portion 191 in the Z direction, and a translucent optical member such as a glass plate may be fitted in the through hole. ..

The lower surface (+ Z side surface) of the shutter holding portion 191 is slidably mounted on the upper surface 131A of the bottom 131 of the carriage 13, and both ends thereof are inserted into the insertion holes 134. It is arranged so as to penetrate in the X direction.
That is, the −X side end portion (first end portion 194) of the shutter holding portion 191 protrudes toward the −X side via the insertion hole 134 on the −X side of the carriage 13, and the + X side end portion (second end portion) of the shutter 192. The end portion 195) projects to the + X side through the insertion hole 134 on the + X side of the carriage 13. The first end portion 194 and the second end portion 195 are formed in a flange shape, whereby the shutter holding portion 191 is prevented from coming off from the carriage 13.

In the shutter mechanism 19 having such a configuration, the window portion 176A is opened and closed by the shutter 192 by the movement of the carriage 13. Specifically, when the carriage 13 is moved to the + X side end (FULL position), the second end 195 comes into contact with the second side surface 103 of the unit housing 10 and shutters to the carriage 13. The holding portion 191 moves to the −X side by a predetermined distance u (open position). As a result, the light passing portion 193 faces the window portion 176A, and the reflected light from the measurement position P can be incident on the spectroscope 17.
On the other hand, when the carriage 13 is moved to the end portion (HOME position) on the −X side, the first end portion 194 comes into contact with the first side surface portion 102 of the unit housing 10, and as shown in FIG. 5, the carriage The shutter holding portion 191 moves to the + X side by a predetermined distance u with respect to 13 (closed position). As a result, the shutter 192 faces the window portion 176A and is closed by the shutter 192.

[CPU function configuration]
FIG. 6 is a block diagram showing a functional configuration of the CPU 154.
The CPU 154 is a calculation unit of the present invention, and by reading and executing various programs stored in the memory 153, as shown in FIG. 6, the scanning control unit 154A, the print control unit 154B, the measurement control unit 154C, and the correction unit It functions as 154D, a transformation matrix calculation unit 154E, an error determination unit 154F, and a reflectance calculation unit 154G.

The scanning control unit 154A outputs a command signal to drive the supply unit 11, the transport unit 12, and the carriage moving unit 14 to the unit control circuit 152. As a result, the unit control circuit 152 drives the roll drive motor of the supply unit 11 to supply the media M to the transfer unit 12. Further, the unit control circuit 152 drives the transport motor of the transport unit 12 to transport a predetermined region of the media M to a position facing the carriage 13 of the platen 122 along the Y direction. Further, the unit control circuit 152 drives the carriage motor 142 of the carriage moving unit 14 to move the carriage 13 along the X direction.

Further, the scanning control unit 154A outputs a command signal to drive the carriage moving unit 14 to the unit control circuit 152 when the position of the shutter 192 is changed. As a result, the unit control circuit 152 moves the carriage 13 to the Home when the shutter 192 is moved to the closed position, and moves the carriage 13 to the Full when the shutter 192 is moved to the open position.

The print control unit 154B outputs a print command signal for driving and controlling the supply unit 11, the transfer unit 12, the carriage movement unit 14, and the print unit 16 based on, for example, print data input from the external device 30. Output to 152. The unit control circuit 152 outputs a print control signal to the printing unit 16 and drives a piezo element provided in the nozzle to eject ink to the media M.

The measurement control unit 154C outputs a measurement command signal for driving the spectroscope 17 to the unit control circuit 152, causes the spectroscope 17 to perform measurement processing, and acquires the reflectance of each wavelength with respect to the measurement position P. .. Further, the measurement control unit 154C drives the spectroscope 17 to perform measurement processing on the reference plate 192A and the media M. The specific measurement processing method will be described later.

The correction unit 154D performs various correction processes based on the reflectance of the media M obtained by the spectroscope 17 for each wavelength. Examples of the correction process include correction of density unevenness and color shift.
The transformation matrix calculation unit 154E performs a calculation process of the transformation matrix Ms described later. The specific calculation method will be described later.
The error determination unit 154F performs error determination processing based on the measurement result of the reference plate 192A.
The reflectance calculation unit 154G performs a process of calculating the reflectance for each wavelength of the media M. The specific calculation method will be described later.

[Spectroscopic measurement and transformation matrix calculation process]
Next, in the printer 1 of the present embodiment, the calculation process of the transformation matrix Ms for calculating the reflectance of the object will be described with reference to the drawings.
FIG. 7 is a flowchart showing an example of the transformation matrix calculation process in the printer 1.
In the printer 1 of the present embodiment, the spectroscope 17 irradiates the media M with illumination light under the control of the measurement control unit 154C, and the light reflected by the media M is separated into light having a plurality of wavelengths by the spectroscopic device 173A. The spectroscopic light of each wavelength is received by the light receiving element 174A. As a result, a detection signal corresponding to the amount of light received by the light receiving element 174A is input from the spectroscope 17 to the control unit 15 as a measurement result. The measurement result includes measured values (voltage values) for a plurality of wavelengths (for example, wavelengths of 16 bands having an interval of 20 nm from 400 nm to 700 nm) when the media M is measured. Then, the reflectance calculation unit 154G directly calculates the reflectance of the media M for each wavelength by applying a transformation matrix to the measured values for each wavelength included in the measurement result.

Since such a transformation matrix needs to be set according to the characteristics of each spectroscope 17, for example, at the time of manufacturing the printer 1, it is measured in advance for each spectroscope 17 and stored in the memory 153. In addition to this, in the present embodiment, the CPU 154 functions as the transformation matrix calculation unit 154E, so that the transformation matrix is calculated even when the light source 179 and the spectroscopic device 173A change over time after the printer 1 is shipped. It becomes possible to update the transformation matrix stored in the memory 153. When the conversion matrix is updated by the printer 1, for example, when a predetermined period has elapsed from the start of use of the printer 1, a guidance message is output to, for example, a display (not shown) to the user. Prompt for update processing. Then, when the user inputs an operation to execute the update process, the transformation matrix calculation process as shown in FIG. 7 is started.

The calculation process of the transformation matrix is performed in a state where the sample Z is arranged on the upper surface of the platen 122, that is, at the position where the media M is arranged. For the sample Z, for example, it is preferable to use ceramic tiles having less deterioration of color such as fading, and n (n is a natural number) (for example, 50 colors) in which RGB gradation values are shaken at substantially equal intervals. Pattern image (color patch) is formed.
In this embodiment, in each of the color patches formed on the sample Z, the reflectance for k (k is a natural number) wavelengths in the target wavelength range that can be measured by the spectroscope 17 (for example, 10 nm intervals from 400 nm to 700 nm). The reflectance of 31 bands) is known, and the reflection spectra of each color are stored in the memory 153 as _{matrices Sn and k.} For example, in the present embodiment, 50 color patches are formed on the sample Z, the reflectance of 31 bands for each color is known, and the reflection spectra of each color are stored in the memory 153 as _{matrices S 50 and 31.}

When the user commands the calculation process of the transformation matrix, the scanning control unit 154A first moves the carriage 13 to the FULL and moves the shutter 192 to the open position (step S1).
After that, the measurement control unit 154C drives the spectroscope 17 to execute a sample measurement process for performing spectroscopic measurement of the sample Z (step S2).
In the sample measurement process, the measurement control unit 154C controls the spectroscopic device 173A and the light receiving element 174A, and for each color of the color patch formed on the sample Z, m (m is a natural number) wavelengths (for example, natural number) in the target wavelength range. Measured values are measured for wavelengths of 16 bands at intervals of 20 nm in the visible light region from 400 nm to 700 nm. In the present embodiment, when light is received by the light receiving element 174A, a current detection signal corresponding to the amount of received light is output from the light receiving element 174A, and the IV converter, amplifier, and AD conversion of the light receiving element holding substrate 174 are output. By signal processing by the device, it is input to the control unit 15 as a digital signal indicating a voltage value. Then, the measured value corresponding to the detection signal is stored in the memory 153 as _{a matrix D n, m.} That is, in the present embodiment, the measured values are stored in the memory 153 as the _{matrices D 50 and 16.} In step S2, the number of measurement bands (m) in the target wavelength region may be the same as the number of measurement bands (k) in the reflection spectrum of the sample Z.

After step S2, the transformation matrix calculation unit 154E executes the transformation matrix calculation process using _{the reflectance matrix Sn, k} stored in the memory 153 and the measured value matrix D _{n, m (step S3).} ).
Here, the transformation matrix Ms can be expressed by the following equation (1) from _{the matrix S n, k} and the matrix D _{n, m.}

_{Sn, k} ^T = Ms · D _{n, m} ^T ... (1)

In the above equation (1), _{T displayed on the right shoulder of the reflectance matrix Sn, k} and the measured value matrix D _{n, m} indicates that it is a transposed matrix.
Here, if the correct transformation matrix Ms is obtained, Ms · D _{n, m} ^T should match _{Sn, m} ^T. Therefore, the _{evaluation function F (Ms) representing the deviation between Sn, k} ^T and Ms · D _{n, m} ^T is set as in the following equation (2) so that the evaluation function F (Ms) becomes the minimum. The transformation matrix Ms can be determined by expanding to.

F (Ms) = | _{Sn, k} -Ms · Dn _{, m} | ² ... (2)

The solution that minimizes the above equation (2) is a solution in which the value obtained by partially differentiating the evaluation function F (Ms) with respect to Ms is 0, as in the case of the least squares error solution. That is, the above equation (2) can be expanded and obtained as the following equation (3).

-2 (D _{n, m} ^T · D _{n, m} ) · Ms + 2D _{n, m} ^T · _{Sn, k} = 0
(D _{n, m} ^T · D _{n, m} ) · Ms = D _{n, m} ^T · S _{n, k}
Ms = (D _{n, m} ^T · D _{n, m} ) ^-1 · D _{n, m} ^T · _{Sn, k} ... (3)

In step S3, the transformation matrix calculation unit 154E calculates the transformation matrix Ms using the matrix Sn _{, k} and the matrix D _{n, m by expanding as in the above equation (3).}

Returning to FIG. 7, when the transformation matrix Ms is calculated in step S3, the transformation matrix calculation unit 154E stores the calculated transformation matrix Ms in the memory 153 (step S4).

[Correction processing]
Next, as an example of the correction process in the printer 1 of the present embodiment, the color shift correction process will be described with reference to the drawings.
FIG. 8 is a flowchart showing an example of the correction process in the printer 1.
The correction process by the printer 1 is performed when the color shift occurs, for example, when the power is turned on or when an instruction to execute the correction process is received.

In the spectroscopic measurement method shown in FIG. 8, first, the scanning control unit 154A moves the carriage 13 to the HOME and the shutter 192 to the closed position (step S10).
After that, the print control unit 154B prints a pattern image for color shift correction on the medium M (step S20). As the pattern image for color shift correction, for example, a color chart in which a plurality of color patches having different colors are arranged along the X direction and the Y direction can be exemplified. The color patch used here may be a color patch of the same color as when the transformation matrix is calculated.
At this time, since the shutter 192 is located at the closed position, the intrusion of foreign matter such as ink mist into the spectroscope 17 at the time of printing is suppressed.

After step S20, the measurement control unit 154C drives the spectroscope 17 to perform a reference plate measurement process for spectroscopically measuring the reference plate 192A which is a reference object (step S30).
FIG. 9 is a flowchart showing a reference plate measurement process.
In the reference plate measurement process in step S30, as shown in FIG. 9, the measurement control unit 154C measures the measured values for light of m wavelengths in the target wavelength range, and the temperature measuring unit 173B measures the temperature. (Step S31). The measurement of the measured value in step S31 is the same process as the sample measurement process in step S2, and the measured value for each wavelength measured in step S2 is acquired. For example, the measurement control unit 154C measures the measured value of 16 bands from 400 nm to 700 nm at intervals of 20 nm, for example.

Next, as shown in FIG. 9, the error determination unit 154F has a correlation coefficient between the initial value of the measured value for each measured wavelength at the time of shipment from the factory stored in the memory 153 and the measured value measured in step S31. R and the inclination α are calculated (step S32).

Next, the error determination unit 154F determines whether or not the correlation coefficient R is equal to or greater than a predetermined reference value H (step S33). The reference value H is a lower limit value of the correlation coefficient R stored in advance in the memory 153, and can be appropriately set according to the tolerance of the spectral measurement result related to the correction process, for example, 0.9. The value of the degree is set.
FIG. 11 is a diagram showing an example of the correlation between the initial value of the measured value and the measured value measured in step S31. In the example of FIG. 11, the horizontal axis is the measured value (initial value) of the wavelength of 16 bands having a 20 nm interval from 400 nm to 700 nm at the time of shipment from the factory, and the vertical axis is the measured value of the same wavelength measured in step S31. As an example, it is an example showing the correlation when the measured value of the received light amount of each band is plotted corresponding to the initial value.
When the window portion 176A is not contaminated and the reference plate 192A is not contaminated, the measured value does not fluctuate so much, so that the variation of the measured value measured in step S31 with respect to the initial value becomes small, and the correlation coefficient R becomes large.
On the other hand, if dirt such as ink mist adheres to the window portion 176A or the reference plate 192A, the measured value of the received light amount fluctuates. Therefore, as shown in FIG. 11, step S31 with respect to the initial value. The variation of the measured value measured in is large. That is, the correlation coefficient R between the initial value and the measured value becomes small. Therefore, in step S33, by determining whether or not the correlation coefficient R is equal to or greater than the reference value H, it is possible to detect stains on the window portion 176A and the reference plate 192A.

When No is determined in step S33 (when R <H), the scanning control unit 154A moves the carriage 13 to the FULL position and opens and closes the shutter 192 to open and close the window portion 176A and the window portion 176A by the wipers 192B and 192C. Cleaning of the reference plate 192A is performed (step S331). When the cleaning of the window portion 176A is completed, the error determination unit 154F adds 1 to the variable “j” (initial value: 0) indicating the number of cleanings (step S332), and determines whether or not j ≧ N (step). S333).

If the error determination unit 154F determines NO in step S333, the error determination unit 154F returns to step S31 and executes spectroscopic measurement of the reference plate 192A again.
If YES is determined in step S333, there may be stains that cannot be removed by cleaning with the wipers 192B and 192C, or accurate spectroscopic measurement may not be performed due to other factors. In this case, the error determination unit 154F outputs an error (step S334). For example, the error determination unit 154F displays an error message on a display or the like (not shown) to urge the user to perform maintenance.
In addition, as a predetermined number of times N for repeating spectroscopic measurement and cleaning, a number of times of about 3 times is usually set.

On the other hand, if YES is determined in step S33, the error determination unit 154F determines whether or not the inclination α is equal to or greater than the threshold value K (step S34). The threshold value K is a lower limit value of the slope α stored in advance in the memory 153, and is set to, for example, a value of about 0.7.
FIG. 12 is a diagram showing an example of the slope of the measured value with respect to the initial value when the measured value of the received light amount of each band is plotted corresponding to the initial value, as in FIG. 11.
When there is no deterioration of the light source, the light receiving amount of each measured wavelength measured in step S31 shows a value close to the initial value, so that the slope α of the measured value with respect to the initial value is close to “1”.
On the other hand, when the amount of light decreases due to deterioration of the light source 179 or the like, the amount of light received for each measurement wavelength becomes uniformly small. Then, as shown in FIG. 12, the slope α of the measured value with respect to the initial value becomes small. Therefore, in step S34, by determining whether or not the inclination α is equal to or greater than the threshold value K, it is possible to detect that the amount of light is reduced due to deterioration of the light source 179 or the like.

If NO is determined in step S34 (α <K), the light source 179 may have deteriorated. In this case, the error determination unit 154F displays an error message on a display or the like (not shown) to urge the user to perform maintenance (step S341).

If YES is determined in step S34, the measurement control unit 154C stores the inclination α and the temperature measurement value T in the memory 153 (step S35), and ends the reference plate measurement process.

Returning to FIG. 8, when the reference plate measurement process is completed, the scanning control unit 154A moves the carriage 13 to the FULL and moves the shutter 192 to the open position (step S40). Then, the control unit 15 executes the pattern image measurement process (step S50).
In the pattern image measurement process, the scan control unit 154A moves the carriage 13 and the media M to sequentially position the measurement area of the spectroscope 17 on the color patch. Then, the measurement control unit 154C performs spectroscopic measurement for each color patch. This spectroscopic measurement is performed in the same manner as the reference plate measurement process shown in FIG. 9, and the measured value D'for each measurement wavelength is stored in the memory 153.

Then, when the measurement is completed for all the color patches, the reflectance calculation unit 154G uses the transformation matrix Ms, the inclination α, the temperature measurement value T, and the measurement value D'stored in the memory 153 as the target media M. The reflectance calculation process for calculating the reflectance of the above is executed (step S60).
FIG. 10 is a flowchart showing the reflectance calculation process.
In the reflectance calculation process of step S60, as shown in FIG. 10, the reflectance calculation unit 154G corrects the measured value D'based on the inclination α and the temperature measured value T (step S61). Here, as for the correction of the measured value D', either the correction by the inclination α or the correction by the temperature measured value T may be performed first. Further, for this correction, the correction table corresponding to the inclination α and the temperature measurement value T may be stored in the memory 153 in advance, or the correction value is calculated according to the inclination α and the temperature measurement value T. May be good.
In the present embodiment, by correcting the measured value D'based on the measurement result of the substrate measurement process and the temperature measurement result, it is possible to eliminate the influence of the deterioration of the light source and the temperature drift of the spectroscopic device and the like. Hereinafter, the corrected measured value D'is referred to as the corrected measured value D.

After that, the reflectance calculation unit 154G calculates the reflectance of the target media M by multiplying the corrected measurement value D by the transformation matrix Ms as shown in the equation (1) (step S62). That is, by applying the transformation matrix Ms to the measured values measured by the spectroscope 17, the reflectance of the target media M can be directly calculated without obtaining the reflectance of the reference plate 192A.
Then, the reflectance calculation unit 154G stores the calculated reflectance in the memory 153 (step S63), and ends the reflectance calculation process.

Returning to FIG. 8, the correction unit 154D compares the reflectance calculated by the reflectance calculation process with the reference reflectance stored in advance in the memory 153, and the color measurement result (for example, XYZ value, L * a *). b * value, etc.) is calculated (step S70). Then, the correction unit 154D performs a color shift correction process based on the color measurement result obtained in step S70 (step S80).
After performing the color shift correction processing, a new color patch is printed, the printing unit prints the color patch on the media M, the spectroscope performs spectroscopic measurement, the measurement result is obtained, and the conversion stored in the memory 153. Calculate the reflectance of the color patch using a matrix. If the reflectance is not as desired, color patch printing and spectroscopic measurement are repeated so that the amount of color shift of the color patch to be printed is within the allowable range.
As described above, since the transformation matrix stored in the memory 153 is used when calculating the reflectance of the color patch, the reflectance can be calculated without measuring the reflectance of the reference object.

[Action and effect of the first embodiment]
The printer 1 of the present embodiment has a spectroscope 17 that measures the amount of light from the target media M for a plurality of wavelengths, and a calculation unit that calculates the reflectance of the media M based on the measurement results by the spectroscope 17. The CPU 154 is provided with the CPU 154, and the CPU 154 calculates the reflectance of the media M by causing the conversion matrix Ms that converts the measured value into the reflectance to act on the measured value measured by the spectroscope 17.

In such a configuration, the CPU 154 can directly calculate the reflectance of the media M from the measured value (voltage value) measured by the spectroscope 17. Therefore, when calculating the reflectance of the media M, it is not necessary to measure the reflectance of the reference color using the reference plate 192A which is a reference material, and the conditions at the time of color measurement are determined by the reference plate 192A and the media M. There is no need to align. Therefore, it is not necessary to arrange the reference plate 192A at the same height as the media M, and the degree of freedom in the arrangement of the reference plate 192A can be increased.

In the present embodiment, the transformation matrix Ms uses the reflectance for k wavelengths of the sample Z whose reflectance is known and the measured value for the m wavelengths when the sample Z is measured by the spectroscope 17. It is calculated.
Therefore, if the sample Z having a known reflectance is prepared, the transformation matrix Ms can be calculated without using a special device. Therefore, the transformation matrix Ms for directly calculating the reflectance from the measured value measured by the spectroscope 17 can be easily calculated.

In the present embodiment, the evaluation function F (Ms) is F (Ms) = | _{Sn, k} −Ms · D _{n, m} | ² , and the transformation matrix Ms is a matrix having the minimum evaluation function F (Ms). be.
Therefore, the transformation matrix Ms can be determined by expanding the evaluation function F (Ms) in the same manner as a general least squares error solution. Therefore, the transformation matrix Ms for directly calculating the reflectance from the measured value measured by the spectroscope 17 can be easily determined.

_{In the present embodiment, the CPU 154 uses the matrix D n, m} of the measured values when the sample Z is measured by the spectroscope 17 and the matrix Sn _{, k} of the known reflectance of the sample Z to obtain the transformation matrix Ms. calculate.
Therefore, if the sample Z having a known reflectance is prepared, the transformation matrix Ms for directly calculating the reflectance from the measured value measured by the spectroscope 17 can be calculated. Therefore, for example, when the light source 179 or the like changes over time due to the printer 1 being used for a long time, the transformation matrix Ms in that state can be calculated, and the reflectance of the media M can be calculated accurately.

In the present embodiment, the printer 1 includes a reference plate 192A which is a reference object, and the CPU 154 disperses based on the measurement result of the reference plate 192A by the spectroscope 17 when the reference plate 192A is irradiated with the light from the light source 179. The measured value D'when the media M is measured by the device 17 is corrected.
Therefore, for example, even if the light amount of the light source 179 of the spectroscope 17 changes, the measured value which is the measurement result of the media M based on the measurement result of the reference plate 192A measured in the state where the light amount of the light source 179 changes. Since D'is corrected, its influence can be eliminated. Therefore, the reflectance of the media M can be calculated accurately.

In the present embodiment, the printer 1 includes a temperature measuring unit 173B for measuring the temperature of the spectroscope 17, and the CPU 154 measures the media M by the spectroscope 17 based on the temperature measurement value T measured by the temperature measuring unit 173B. The measured value D'at the time of this is corrected.
Therefore, for example, even if the characteristics of the spectroscopic device 173A change due to a temperature change, if the relationship between the characteristics of the spectroscopic device 173A and the temperature is obtained in advance, the change in the characteristics can be grasped by the measured temperature measurement value T. can do. Therefore, the measured value D'correction can be performed according to the change in the characteristics, and the reflectance of the object can be calculated with high accuracy.

[Second Embodiment]
Next, the second embodiment will be described.
In the first embodiment, as shown in the equation (2), the transformation matrix Ms is determined by expanding the _{evaluation function F (Ms) = | Sn, k} −Ms · Dn _{, m} | ^2. , In the second embodiment, the formula for determining the transformation matrix Ms is different from the first embodiment.

In the above equation (2), the transformation matrix Ms capable of calculating the reflectance as the best linear bias estimator is obtained under the condition that the _{matrices Sn, k} and the matrices are _{not included in the error D n, m.} It is possible to calculate. However, if an _{error is included in the matrix Sn, m} or the matrix Dn _{, m} , it becomes a parameter of the overfitting state depending on the degree. In this case, the parameters of the transformation matrix Ms determined by expanding this evaluation function F (Ms) are obtained as a state in which very large values and small values are mixed, and the variation of the parameters becomes large. .. In this case, when the conversion matrix is applied to the measured value of the measurement result by the spectroscope 17 to calculate the reflectance, if the measured value of the measurement result is a measured value including an error similar to that at the time of calculating the conversion matrix. Although it is possible to obtain the reflectance with high accuracy, the estimation accuracy of the reflectance may decrease depending on the degree and variation of the error included in the measured value of the measurement result (overfitting). In order to suppress this overfitting, it is necessary to add a constraint to reduce the variation of parameters. Therefore, using Lagrange's undetermined multiplier method, the above equation (2) is replaced as follows.

F (Ms) = | _{Sn, k} -Ms · D _{n, m} | ² + β · Ms ^T · Ms ... (4)

In the above equation (4), β is a constant called a hyperparameter. In the above equation (4), it is added βMs ^T Ms is number term to multiply the evaluation function F (Ms). Therefore, a constraint term that minimizes the variance (or Euclidean norm) of the parameters of the transformation matrix Ms is added to the evaluation function F (Ms), and can be regularized. As a result, the variation in the parameters of the transformation matrix Ms can be reduced, and the transformation matrix that can suppress overfitting can be calculated. That is, when the measured value of the measurement result is converted into the reflectance by using the transformation matrix Ms, the reflectance can be calculated with high accuracy even if the error included in the measured value varies.

[Modification example]
The present invention is not limited to the above-described embodiment, and modifications, improvements, and the like to the extent that the object of the present invention can be achieved are included in the present invention.

In each of the above embodiments, the measured value is an example of a digital signal indicating a voltage value processed by an IV converter, an amplifier, and an AD converter of the light receiving element holding substrate 174, but the present invention is limited to this. No. For example, the detection signal (current value) output from the light receiving element 174A may be sampled at the timing of switching the spectral wavelength by the spectroscopic device 173A, so that the current value (current spectrum) for each wavelength may be acquired as a measured value. .. In this case, as the conversion matrix Ms, a matrix that converts the current value into the reflectance is used.

In each of the above embodiments, the reference plate 192A, which is a reference object, is an example of a white plate having a reflectance of 99% or more for light of each wavelength in a predetermined wavelength range (for example, visible light range), but the present invention is limited to this. No. The reference color of the reference plate 192A is not limited to white, and may be any color as long as the reference for carrying out the measurement can be set. In this case, it is preferable that the reflectance of the reference color is known, but the reflectance is not limited to this. That is, it is sufficient that the initial value of the detection signal output from the light receiving element is stored in the memory when the reference plate is irradiated with the light of the light source.

In each of the above embodiments, the reference plate 192A is provided at a position facing the window portion 176A of the shutter 192, but the present invention is not limited to this. For example, the reference plate 192A may be provided on the upper surface of the platen 122, and may be provided at a position that can be measured by the spectroscope 17. Further, instead of the reference plate, the shutter 192 itself, a columnar substance, or the like may be used as the reference object.

In each of the above embodiments, an example of calculating the transformation matrix Ms when a predetermined period has elapsed from the start of use of the printer 1 is shown, but the present invention is not limited to this. For example, the printer 1 may not perform the calculation process of the transformation matrix Ms, but may use the transformation matrix Ms measured in advance at the time of manufacturing the printer 1 and stored in the memory 153 for the reflectance calculation process of the media M. In this case, since the conversion matrix calculation process is not performed in the printer 1, the transformation matrix calculation unit 154E may not be provided.
Further, the transformation matrix Ms calculated in the above embodiment is stored in the memory 153 in place of the transformation matrix measured in advance at the time of manufacture, and is constantly used for the reflectance calculation process of the media M. You may. Further, the transformation matrix Ms may be calculated and updated as necessary.

In each of the above embodiments, the temperature measuring unit 173B shows an example provided on the spectroscopic device holding substrate 173, but the present invention is not limited to this. For example, the temperature measuring unit may be provided on the light receiving element holding substrate 174, and may be provided at a position where the temperature of the spectroscope 17 can be measured. Further, a plurality of temperature measuring units may be provided.

In each of the above embodiments, an example in which the temperature is measured by the temperature measuring unit 173B in the reference plate measuring process in step S30 is shown, but the present invention is not limited to this. For example, the temperature measurement by the temperature measuring unit 173B may be performed in the pattern image measurement process of step S50, and the temperature may be measured in the correction process.

In each of the above embodiments, the shutter 192 can be moved in the X direction with respect to the carriage 13 by moving the shutter holding portion 191, but the present invention is not limited to this. For example, the shutter 192 may be provided so as to be rotatable around a rotation axis parallel to the Z direction, and may be configured to be movable between a closed position and an open position by rotating around the rotation axis.
Further, the shutter 192 was moved by moving the carriage 13 and bringing the first end portion 194 and the second end portion 195 into contact with the unit housing 10, but for example, a drive source such as a motor was moved to the carriage 13. It may be mounted and the shutter 192 may be moved by the driving force from the driving source.

In each of the above embodiments, the printer 1 includes a printing unit 16 that ejects ink to form an image, which is a so-called inkjet printer. However, the present invention is not limited to this, and the image forming material is transferred to the media M. The configuration of each of the above embodiments can be applied to a printer provided with a printing unit for forming an image. As such a printer, for example, a so-called thermal transfer printer in which an ink ribbon as an image forming material is heated and melted and transferred to the media M, or a latent image image is developed using toner, and the developed image is used as a medium. A so-called electrophotographic printer that transfers to M can be mentioned.

Further, although the printer 1 is shown as an electronic device, the present invention is not limited to this. For example, it may be a measuring device that does not have a printing unit 16 and only measures the media M. Further, for example, the spectroscopic measurement device of the present invention may be incorporated into a quality inspection device for inspecting the quality of printed matter manufactured in a factory or the like, and the spectroscopic measurement device of the present invention may be incorporated into any other electronic device.

In addition, the specific structure at the time of carrying out the present invention can be appropriately changed to another structure or the like within the range in which the object of the present invention can be achieved.

1 ... Printer (electronic device), 10 ... Unit housing, 13 ... Carriage, 15 ... Control unit (control unit), 17 ... Spectrometer, 153 ... Memory, 154 ... CPU (Calculation unit), 154D ... Correction unit, 154E ... Transformation matrix calculation unit, 154F ... Error determination unit, 154G ... Reflectance calculation unit, 192 ... Shutter, 192A ... Reference plate (reference object), M ... Media (object), Z ... Sample.

Claims (9)

A spectroscope that measures the amount of light from an object for multiple wavelengths,
An arithmetic unit that calculates the reflectance of the object based on the measurement results of the amount of light for the plurality of wavelengths, and
A reference material with a known reflectance for light of each wavelength in a predetermined wavelength range,
An error in determining whether or not the correlation coefficient between the measurement result for the reference object and the initial value of the measurement result for the reference object when the reference object is irradiated with light from a light source is larger than a predetermined value. Equipped with a judgment unit
Whether the slope of the regression line between the measurement result for the reference object and the initial value of the measurement result for the reference object when the reference object is irradiated with the light from the light source is larger than a predetermined threshold value in the error determination unit. Judge whether or not,
When the error determination unit determines that the correlation coefficient is larger than the predetermined value and the inclination is larger than the predetermined threshold value , the calculation unit converts the measurement result into a reflectance. A spectroscopic measuring apparatus characterized in that a transformation matrix is applied to the measurement result to calculate the reflectance of the object. In the spectroscopic measuring apparatus according to claim 1,
The conversion matrix is the reflectance for k (k is a natural number) wavelength of a sample whose reflectance is known, and the measurement result for m (m is a natural number) wavelength when the sample is measured by the spectroscope. A spectroscopic measuring device characterized by being a matrix calculated using and. In the spectroscopic measuring apparatus according to claim 2,
_{Let Sn} and k be the known reflectance matrices for the k wavelengths in each of the n (n is a natural number) samples having different colors.
_{Let D n and m} be the matrix of the measurement results of the amount of light for the m wavelengths in each of the n samples.
Let the transformation matrix be Ms and
The evaluation function F (Ms) is set to F (Ms) = | _{Sn, k} -Ms · Dn _{, m} | ² .
The transformation matrix Ms is a spectroscopic measuring apparatus characterized in that the evaluation function F (Ms) is the minimum matrix. In the spectroscopic measuring apparatus according to claim 2,
_{Let Sn} and k be the known reflectance matrices for the k wavelengths in each of the n (n is a natural number) samples having different colors.
_{Let Dn, m} be the matrix of the measurement results of the amount of light for the m wavelengths in each of the n samples measured by the spectroscope.
Let Ms be the transformation matrix and β be the constant.
The evaluation function F (Ms) is set to F (Ms) = | _{Sn, k} -Ms · D _{n, m} | ² + β · Ms ^T · Ms.
The transformation matrix Ms is a spectroscopic measuring apparatus characterized in that the evaluation function F (Ms) is the minimum matrix. The spectroscopic measuring apparatus according to any one of claims 1 to 4.
The calculation unit uses the measurement results for m (m is a natural number) wavelengths when measuring a sample whose reflectance is known, and the reflectances of k (k is a natural number) wavelengths of the sample. A spectroscopic measuring device characterized in that the conversion matrix is calculated. The spectroscopic measuring apparatus according to any one of claims 1 to 5 .
Before SL computing unit on the basis of the measurement results for the reference object when irradiated with light from the light source to the reference object, the spectral measurement device and correcting the measurement results when measuring the object .. The spectroscopic measuring apparatus according to any one of claims 1 to 6.
Further provided with a temperature measuring unit for measuring the temperature of the spectroscope,
The calculation unit is a spectroscopic measurement device characterized in that it corrects a measurement result when the object is measured based on the temperature measured by the temperature measurement unit. The spectroscopic measuring apparatus according to any one of claims 1 to 7.
A control unit that controls the calculation unit and
An electronic device characterized by being equipped with. A spectroscope measures the amount of light from an object for multiple wavelengths and
The correlation coefficient between the measurement result for the reference object and the initial value of the measurement result for the reference object when the light is applied from the light source to the reference object whose reflectance for each wavelength in a predetermined wavelength range is known is , The error judgment unit determines whether or not it is larger than the predetermined value, and
The error indicates whether or not the inclination of the regression line between the measurement result of the reference object and the initial value of the measurement result of the reference object when the reference object is irradiated with light from the light source is larger than a predetermined threshold value. When the determination unit determines and the error determination unit determines that the correlation coefficient is larger than the predetermined value and the inclination is larger than the predetermined threshold value, the calculation unit determines the plurality of wavelengths. A spectroscopic measurement method characterized in that a conversion matrix for converting a measurement result of light intensity into a reflectance is applied to a measurement result for the object to calculate the reflectance of the object.

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