JP4076560B2 - Image recording device - Google Patents

Description

  The present invention belongs to the technical field of an image recording apparatus that receives image data (image information) from an external image data supply source and performs image recording.

Scanned image recording is used in various applications such as printers and copiers.
Scanning image recording uses recording means that records an image only in one direction (main scanning direction), and moves the recording material and recording means relatively in a direction (sub-scanning direction) perpendicular to the main scanning direction. By doing so, it is image recording in which an image is recorded two-dimensionally on a recording material.

For example, in the case of thermal image recording, a thermal head having a glaze in which heating elements for recording an image by heating a thermal recording layer of a thermal recording material are arranged in one direction (main scanning direction) is used. By scanning and transporting the thermal material or thermal head in a state of being slightly pressed against the material (thermal recording layer), the thermal head and the thermal material are moved relatively in the sub-scanning direction orthogonal to the extending direction of the glaze, By applying energy to each of the glaze heating elements and heating in accordance with the recorded image, the thermal recording layer of the thermal material is heated to perform image recording.
Such thermal image recording has been conventionally used for recording of ultrasonic diagnostic images, etc., but since it has advantages such as no need for wet development and easy handling, in recent years, In applications that require large and high-quality images, such as CT diagnosis, MRI diagnosis, and X-ray diagnosis, as well as small-size image recording such as sonic diagnosis, use for image recording for medical diagnosis is also being considered. ing.

  In the case of image recording by light beam scanning, the photosensitive material is conveyed in the sub-scanning direction orthogonal to the main scanning direction while deflecting the light beam modulated according to the recorded image in the main scanning direction, or In the case of image recording using an LED array, each light emitter (pixel) of the LED array is moved according to the recorded image while relatively moving the LED array and the photosensitive material in a direction orthogonal to the arrangement direction of the LED array. ), The photosensitive material is two-dimensionally scanned and exposed to perform image recording.

By the way, in such scanning image recording, even when uniform density image recording is performed, so-called shading, in which image density unevenness occurs in the main scanning direction due to the individual characteristics of the recording apparatus, results in deterioration in image quality. There is a problem that.
For example, in the above-described thermal image recording, the shape of the glaze of the thermal head is not uniform over all pixels and inevitably varies, so even if the same heat generation energy is supplied, the heat generation amount of each heating element A difference occurs, which becomes a density unevenness of the recorded image and causes shading.

In order to prevent such deterioration in image quality due to shading, so-called shading correction is performed in some image recording apparatuses to correct image density unevenness due to shading.
This shading correction is performed as follows, for example.
First, image recording is actually performed with image data having a uniform density in the main scanning direction, the density of the recorded image is measured, and the image density of all pixels is made uniform with reference to a pixel having a minimum density or the like. An appropriate shading correction coefficient is calculated for each pixel and stored in a memory or the like (setting of shading correction conditions). After the correction conditions are set in this way, at the time of actual image recording, shading correction is performed by multiplying the image data supplied from the image data supply source by the shading correction coefficient.

However, the shading state changes over time, and as the image recording apparatus continues to be used, it becomes impossible to perform suitable shading correction under the initially set shading correction conditions, and the image quality gradually deteriorates. There is a point.
For example, in the case of the above-mentioned thermal image recording, the glaze (protective layer) is worn and deteriorated as the image recording is performed, and dirt is attached to the glaze, so the amount of heat generated with respect to the supplied heat generation energy varies with time. End up. Moreover, the variation in the amount of heat generated due to these differs for each pixel. For this reason, the shading state changes with time, and suitable correction cannot be performed under the original shading correction conditions.

Such a decrease in the image quality of the recorded image is a serious problem in applications where high-quality image recording is required. In particular, in applications where high-quality images are required, such as the above-described medical thermal recording apparatus, it becomes an obstacle to image observation and a serious problem that leads to a diagnosis error.
In order to prevent such an inconvenience, it is necessary to reset the shading correction conditions in accordance with the deterioration of the image quality. For this purpose, a service person goes to the user to perform the resetting; Send the image for the above-mentioned shading correction condition setting from the user, use it to reset the correction condition, record it on a recording medium such as a floppy disk, and send it to the user It is necessary to download the data at the user's site; both the user side and the service side are burdensome.

  An object of the present invention is to solve the above-described problems of the prior art, and can suitably cope with a change in shading over time. It is an object of the present invention to provide an image recording apparatus that can record images.

  In order to achieve the above object, the present invention provides an image processing unit that receives image data from an external image data supply source and performs image processing including at least shading correction on the image data to obtain image data for recording; An output unit that outputs image data of an image for setting shading correction conditions, an image recording unit that records an image according to image data output from the image processing unit or the output unit, and recording by the image recording unit Reading means for reading the image, and based on a reading result obtained by reading the image for setting the shading correction condition by the reading means, to calculate a first shading correction condition by the reading means, From the first shading correction condition to the already set initial shading correction condition And setting means for setting a second shading correction condition used for the shading correction in the image processing unit from the multiplied data obtained by multiplying the initial shading correction condition and the difference. An image recording apparatus characterized by the above is provided.

  Here, it is preferable that the first shading correction condition is calculated using only a low frequency component from an image reading result for setting the shading correction condition.

  Further, a low-density image and a high-density image are formed as images for setting the shading correction conditions, and among the reading results of the images for setting the shading correction conditions, a low-frequency image is changed to a high frequency. It is preferable that the first shading correction condition is calculated by extracting the low frequency components from the high density image.

  The initial shading correction condition further includes a first memory storing the initial shading correction condition and a second memory storing the difference, and the setting unit stores the initial shading stored in the first memory. Preferably, the multiplied data is obtained by multiplying the correction condition and the difference stored in the second memory, and the second shading correction condition is set from the multiplied data.

  The mask size for image reading by the reading unit is preferably 200 μm to 1 mm.

  In addition, the image for setting the shading correction condition is read a plurality of times at different positions in a direction orthogonal to the shading generation direction by the reading means, and the first shading correction condition is calculated using the read result. It is preferable to do this.

  The image recording unit records an image on a transparent recording material, and the reading unit includes a light source, an imaging lens, an aperture, and a sensor, or an LED or laser light source. It is preferable that an image recorded on the recording material is read by detecting transmitted light of the recording material.

Further, the output means outputs a density correction image for further setting a density correction condition, and the image recording unit further outputs image data of the density correction image output from the output means. Preferably, the density correction image is recorded on the recording material, and the density correction condition in the image processing unit is set based on the reading result of the density correction image by the reading unit.
Furthermore, it is preferable to measure the sharpness from the result of reading the image by the reading means.

  According to the image recording apparatus of the present invention, it is possible to suitably cope with a change in shading over time, and it is possible to stably record a high-quality image without deterioration in image quality due to shading over a long period of time.

Hereinafter, the image recording apparatus of the present invention will be described in detail based on a preferred embodiment shown in the accompanying drawings.
FIG. 1 shows a schematic diagram of an example of a thermal recording apparatus according to the image recording apparatus of the present invention.
A thermal recording apparatus 10 (hereinafter referred to as a recording apparatus 10) shown in FIG. 1 performs thermal image recording on a thermal recording material in which a thermal recording layer is formed on one side of a resin film or paper as a support. In the illustrated example, as an example, a heat-sensitive recording material A (hereinafter referred to as heat-sensitive material A) formed by forming a heat-sensitive recording layer on one surface of a transparent polyethylene terephthalate film (PET) as a support. Use.
Such a recording apparatus 10 includes a loading unit 14 in which a magazine 24 containing a heat-sensitive material is loaded, a supply and conveyance unit 16, a recording unit 18 that records a heat-sensitive image on the heat-sensitive material using a thermal head 66, and setting of shading correction conditions. For example, a shading correction image reading unit 20 (hereinafter, referred to as a reading unit 20) that performs image reading and a discharge unit 22.
As shown in FIG. 2, an image processing device 80, an image memory 82, and a recording control device 84 are connected to the thermal head 66 of the recording unit 18.

  In such a recording apparatus 10, the thermal material A is conveyed to the recording unit 18 by the supply conveyance unit 16 and the thermal head 66 is pressed against the thermal material A, while the glaze extending direction, that is, the main scanning direction (FIG. 1). In addition, the thermal material A is conveyed in the sub-scanning direction orthogonal to the direction perpendicular to the paper surface in FIG. Do.

  Note that the image recording apparatus of the present invention is not limited to this, and an image recording apparatus that performs heat transfer using a separation transfer type thermal recording material, a thermal head, or a heating laser, or an LED array or a light beam. The present invention can also be suitably used for an image recording apparatus that performs image recording by scanning and exposing a material.

In the illustrated example, the heat-sensitive material A is a cut sheet having a predetermined size such as a B4 size.
Such a heat-sensitive material A is usually a laminated body (bundle) of a predetermined unit such as 100 sheets and is packaged by a bag or a belt. In the illustrated example, the heat-sensitive recording layer remains in a bundle of a predetermined unit. Are stored in the magazine 24 of the recording apparatus 10 with the bottom surface taken out from the magazine 24 one by one and used for thermal image recording.

The magazine 24 is a housing having a lid 26 that can be freely opened and closed. The magazine 24 stores the heat-sensitive material A and is loaded into the loading unit 14 of the recording apparatus 10.
The loading unit 14 includes an insertion port 30 formed in the housing 28 of the recording apparatus 10, a guide plate 32, guide rolls 34 and 34, and a stop member 36. The magazine 24 has the lid 26 side first. The recording device 10 is inserted into the recording device 10 through the insertion port 30, and is guided to the stop plate 36 while being guided by the guide plate 32 and the guide roll 34, so that the recording device 10 is loaded at a predetermined position.

The supply / conveyance means 16 takes out the heat-sensitive material A from the magazine 24 loaded in the loading section 14 and conveys it to the recording section 18. The single-wafer mechanism using the suction cup 40 that adsorbs the heat-sensitive material A by suction, conveyance A means 42, a conveyance guide 44, and a regulating roller pair 52 positioned at the exit of the conveyance guide 44 are included.
The conveying means 42 includes a conveying roller 46, a pulley 47 a coaxial with the conveying roller 46, a pulley 47 b and a tension pulley 47 c connected to a rotational drive source, an endless belt 48 stretched around these three pulleys, The nip roller 50 pressed by the roller 46 is configured, and the tip of the heat-sensitive material A sheeted by the suction cup 40 is sandwiched between the conveyance roller 46 and the nip roller 50 to convey the heat-sensitive material A.

When an instruction to start recording is issued in the recording apparatus 10, the lid body 26 is opened by an unillustrated opening mechanism, and a single-wafer mechanism using the suction cup 40 takes out one thermal material A from the magazine 24, and the thermal material A The leading end is supplied to the conveying means 42 (conveying roller 46 and nip roller 50). When the heat-sensitive material A is sandwiched between the conveying roller 46 and the nip roller 50, the suction by the suction cup 40 is released, and the supplied heat-sensitive material A is guided to the regulating roller pair 52 by the conveying means 42 while being guided by the conveying guide 44. Be transported.
Note that when the heat-sensitive material A to be used for recording is completely discharged from the magazine 24, the lid 26 is closed by the lid opening mechanism.

The distance from the conveying means 42 to the regulating roller pair 52 defined by the conveying guide 44 is set slightly shorter than the length in the conveying direction of the thermal material A, and the tip of the thermal material A is moved by the conveying means 42. Although the control roller pair 52 is reached, the control roller pair 52 is initially stopped, and the tip of the heat-sensitive material A is stopped and positioned here.
When the leading end of the thermal material A reaches the regulating roller pair 52, the temperature of the thermal head 66 (glaze 66a) is confirmed. If the temperature of the thermal head 66 is a predetermined temperature, the thermal material A by the regulating roller pair 52 is confirmed. Is started, and the heat-sensitive material A is conveyed to the recording unit 18.

FIG. 2 shows a schematic diagram of the recording unit 18 and the reading unit 20.
The recording unit 18 includes a thermal head 66, a platen roller 60, a cleaning roller pair 56, a guide 58, a cooling fan 76 (see FIG. 1) and a guide 62 for cooling the thermal head 66, and an image processing apparatus 80 constituting a recording control system. An image memory 82, a recording control device 84, and a pattern generator 81.
The thermal head 66, for example, performs thermal image recording with a recording (pixel) density of about 300 dpi capable of recording an image up to a maximum B4 size, and includes one heating element that performs thermal recording on the thermal material A. It has a thermal head main body 66b formed with glazes 66a arranged in a direction (perpendicular to the paper surface in FIGS. 1 and 2), that is, in the main scanning direction, and a heat sink 66c fixed to the thermal head main body 66b. The thermal head 66 is supported by a support member 68 that is rotatable about a fulcrum 68a in the direction of arrow a and in the opposite direction.

The platen roller 60 rotates at a predetermined image recording speed while holding the heat sensitive material A in a predetermined position, and conveys the heat sensitive material A in the sub-scanning direction (arrow b direction in FIG. 2) orthogonal to the main scanning direction.
The cleaning roller pair 56 is a roller pair composed of an adhesive rubber roller 56a, which is an elastic body, and a normal roller 56b. The adhesive rubber roller 56a removes dust and the like adhering to the heat-sensitive recording layer of the heat-sensitive material A, and glaze 66a. This prevents dust from adhering to the image and from adversely affecting image recording.

In the illustrated recording apparatus 10, before the heat-sensitive material A is conveyed, the support member 68 is rotated upward (in the direction opposite to the arrow a direction), and the thermal head 66 (glaze 66 a) and the platen roller 60. There is no contact.
When the conveyance by the regulating roller pair 52 is started, the heat sensitive material A is then sandwiched between the cleaning roller pair 56 and further conveyed while being guided by the guide 58. When the leading end of the heat sensitive material A is conveyed to the recording start position (position corresponding to the glaze 66a), the support member 68 rotates in the direction of arrow a, and the heat sensitive material A becomes the glaze 66a of the thermal head 66 and the platen roller 60. And the glaze 66a is pressed against the recording layer, and the heat sensitive material A is held at a predetermined position by the platen roller 60, while the platen roller 60 (and the regulating roller pair 52 and the conveying roller pair 63) has an arrow. It is conveyed in the b direction.
Along with this conveyance, the thermal image recording is performed on the thermal material A by heating the heating elements of the glaze 66a according to the recorded image.

As described above, the recording control system of the thermal head 66 basically includes the image processing device 80, the image memory 82, the recording control device 84, the pattern generation unit 81, and the image processing device 80 and the image data supply source R or pattern. The switch 83 is configured to switch the connection with the generator 81.
Image data (image information) from an image data supply source R such as CT or MRI is sent to an image processing apparatus 80 formed by combining various image processing circuits and memories. That is, in a normal state, the switch 83 connects the image data supply source R and the image processing device 80.

The image data supplied from the image data supply source R is formatted (enlargement / reduction, frame allocation) as necessary in a processing unit (not shown), and then first, the sharpness correction unit 80A emphasizes the contour of the image. Sharpness correction (sharpness processing) is performed, and then the gradation correction unit 80B performs gradation correction to obtain an appropriate image according to the γ value of the thermal film A, and the recording control device 84. Is converted into image data corresponding to the driving of the thermal head 66 by the temperature, and then the temperature correction unit 80C performs temperature correction for adjusting the heat generation energy according to the temperature of the heat generating element, and then the shading correction unit 80D performs the above-described shading. Then, the resistance value correction unit 80E performs resistance value correction for correcting the difference in resistance value of each heating element. In addition, the black ratio correction unit 80F performs black ratio correction to develop image data corresponding to the same density at the same density regardless of the change in resistance value of the heating element due to heating, and thermal recording by the thermal head 66 is performed. Is output to the image memory 82 as image data.
Here, the shading correction unit 80D also serves as a setting unit that sets shading correction conditions.

The recording controller 84 sequentially reads the image data stored in the image memory 82 line by line in the main scanning direction, and modulates the image signal according to the read thermal recording image data (voltage application time width corresponding to the image). Are output to the thermal head 66 in accordance with a heat generation signal that is a reference clock for heat generation.
Each image recording point of the thermal head 66 generates heat according to the image signal, and as described above, thermal recording is performed while the thermal film A is conveyed in the direction of arrow b by the platen roller 60 or the like.

The heat-sensitive material A for which heat-sensitive recording has been completed is conveyed to the platen roller 60 and the conveying roller pairs 63 and 64 while being guided by the guide 62 and is discharged to the tray 72 of the discharge unit 22. The tray 72 protrudes to the outside of the recording apparatus 10 through a discharge port 74 formed in the housing 28, and the heat-sensitive material A on which an image is recorded is discharged to the outside through the discharge port 74 and is taken out.
Here, in the (thermosensitive) recording apparatus 10 according to the image recording apparatus of the present invention, the (shading correction image) reading unit 20 is disposed between the conveyance roller pairs 63 and 64 on the downstream side of the recording unit 20. Yes.

As described above, it is difficult to make the shape of the glaze 66a of the thermal head 66 uniform over all the pixels, and usually there is a certain degree of shape variation in each pixel, and the amount of heat generated by each heating element. Is different also in the position in the extending direction of the glaze 66a. For this reason, even when thermal recording is performed using image data corresponding to the same density, density unevenness due to this shape variation and position, so-called shading, occurs.
In the recording apparatus 10, in order to correct the density unevenness, the shading correction unit 80D performs shading correction.

In the shading correction, for example, the heat energy of image data having a predetermined density is supplied to all the pixels (heat generating elements) of the thermal head 66 to actually form a thermal image, and the image density is measured using a densitometer or the like. For example, a correction coefficient is calculated for each pixel so that the density of the formed thermal image is uniform over all pixels with reference to the pixel having the lowest density, and a shading correction unit 80D is set by setting shading correction conditions. This is performed by multiplying the image data by a correction coefficient in the shading correction unit 80D at the time of thermal recording.
However, the shading state changes with time due to wear deterioration, dirt, etc. of the glaze 66a, and as the recording apparatus 10 continues to be used, suitable shading correction cannot be performed under the initially set correction conditions. As described above, the image quality gradually deteriorates.

  On the other hand, in the recording apparatus 10 of the present invention, an image (a chart for setting correction conditions) for setting shading correction conditions (hereinafter referred to as correction conditions) from the pattern generation unit 81 as time passes. The data is output, the chart is recorded on the thermal material A by the thermal head 66, and this is read by the reading unit 20 to obtain image data of the chart. The shading correction unit 80D uses this image data to set the correction condition. By resetting (changing), appropriate shading correction can be performed regardless of time, and a thermal image with high image quality can be recorded stably over a long period of time.

The pattern generation unit 81 is, for example, a memory in which image data such as a correction condition setting chart is stored, or a processing circuit that generates these image data.
When a predetermined number of sheets (for example, about 1000 to 10,000 sheets) of thermal recording is performed in the recording apparatus 10 or when an instruction for resetting correction conditions is issued by the user, the switch 83 is switched to switch between the pattern generator 81 and the pattern generator 81. The image processing device 80 is connected, the pattern generation unit 81 outputs image data of a chart for setting correction conditions, and the image processing device 80 that has received this performs predetermined processing on the image data, The image data is output to the memory 82 as chart image data.

The image data of this chart may be the same as the normal (shading) correction condition setting. For example, image data of the same density is read across all pixels in the main scanning direction (image data for correction condition setting). Image data that can be recorded in the sub-scanning direction by a length sufficient for (capturing).
There is no particular limitation on the density of the chart.
Here, as for density unevenness due to shading, unevenness of high frequency components is conspicuous in low density images, and unevenness of low frequency components is conspicuous in high density images. Therefore, the density of the chart may be appropriately determined according to the purpose of use of the formed image.
Alternatively, if the image data for resetting the correction conditions can be captured at a high density, low density and high density images are formed as a chart, and high frequency component information is obtained from the low density chart. It is also preferable to take out the information of the low frequency components from the chart and set the correction condition using both.

Similar to the above-described image recording, the image data of this chart is read from the image memory 82 by the recording control device 84, and the chart is recorded on the thermal material A by the thermal head 66. In the illustrated recording apparatus 10, this image is read by the reading unit 20 disposed between the conveyance roller pairs 63 and 64.
The reading unit 20 includes a reading unit including a light source 86 and a reading device 88, an A / D converter 90, and a memory 92.

As shown in FIG. 3, the light source 86 is a rod-like fluorescent lamp, a halogen lamp, or the like, and extends in the main scanning direction so as to sufficiently cover the glaze 66a (the main scanning direction of the heat sensitive material A).
The reading device 88 includes a condensing lens 94, an aperture 96, and a sensor 98, and is disposed at a position facing the light source 86 with the conveyance path of the heat sensitive material A interposed therebetween. When the chart recorded on the heat-sensitive material A is conveyed to a reading position by the reading device 88, the light emitted from the light source 86 and transmitted through the heat-sensitive material A (chart) is condensed by the condenser lens 94 and the aperture 96 is collected. And is read photoelectrically by the sensor 98. As shown in FIG. 3, the reading device 88 is moved at a predetermined speed in the main scanning direction at a position facing the light source 86 by a moving unit (not shown), thereby reading the chart in the entire main scanning direction.
The detection that the chart is conveyed to the reading position by the reading device 88 may be detected by detecting the output fluctuation of the sensor 98, detecting the conveyance amount of the thermal material A by the platen roller 60, or the like.

The size of the aperture of the aperture 96 (that is, the mask size for reading) is not particularly limited, and may be appropriately determined according to the target resolution or the frequency of the unevenness component that is predicted to be generated by shading. The thickness is preferably about 200 μm to 1 mm.
The moving method of the reading device 88 is not particularly limited, and various known methods such as screw transmission, winding transmission, and gear transmission such as rack and pinion can be used.

The reading of the chart by the reading device 88 may be performed while the heat-sensitive material A is being conveyed, or may be performed while the conveyance is stopped.
In addition, by reading the chart multiple times at different positions in the direction orthogonal to the shading generation direction, that is, in the sub-scanning direction, abnormal data with significantly different densities can be removed or averaged when setting correction conditions. Improvement in accuracy due to the conversion can be realized, and a preferable result can be obtained. In addition, when performing this multiple times of reading, you may perform multiple times of reading while conveying the heat sensitive material A, perform intermittent conveyance, and after carrying out reading, slightly convey the heat sensitive material A. Reading different positions in the sub-scanning direction may be repeated. Further, multiple readings may be performed in one direction or in a reciprocating direction.

  In the illustrated example, the reading means uses a long light source 86 and a reading device 88 using a condensing lens 94, an aperture 96 and a sensor 98. However, in the present invention, the reading means is not limited to this. Alternatively, for example, an LED or a laser light source may be used as a light source, and a reading device having no lens or aperture may be used. Further, instead of using a long light source, a point light source may be used, and the reading device 88 and the light source may be moved in synchronization with each other, and reading may be performed by using a line sensor to fix the reading device. Also good.

The chart image data read by the sensor 98 of the reading device 88 is A / D converted by the A / D converter 90 and stored in the memory 92.
The shading correction unit 80D of the image processing device 80 resets (changes) the correction conditions using the image data stored in the memory 92, that is, calculates a shading correction coefficient corresponding to each pixel. This is performed using this correction condition.

Here, the new correction condition may be set using various known methods using only the image data of the read chart.
However, the correction conditions initially set in the recording apparatus 10 are set based on extremely high-precision and high-density image data because image data can be measured at the factory level. On the other hand, the image data measured in the recording apparatus 10 is inevitably inferior in accuracy and density as compared to the factory level in consideration of cost and apparatus size. Therefore, if the correction condition is set using only the chart image data read by the reading device 88, the image quality may be deteriorated.
Therefore, in the illustrated recording apparatus 10, the correction conditions initially set in the recording apparatus 10 (hereinafter, referred to as initial correction conditions) and the difference therebetween are stored in the memory 92, and the shading correction unit 80 </ b> D The correction condition is multiplied by the difference to obtain a reset correction condition.

As shown in FIG. 2, the memory 92 includes a first memory 92a, a second memory 92b, a switch 92c, and a multiplier 92d.
The first memory 92a is a memory that stores initial correction conditions, and the second memory 92b is a memory that stores a difference with respect to the initial correction conditions stored in the memory 92a.
When resetting the correction conditions, the shading correction unit 80D switches the switch 92c to the a side, reads the initial correction conditions stored in the first memory 92a, and records the chart. This chart is read by the reading device 88, and the image data (or correction conditions set from now on) is stored (updated) in the second memory 92b as difference data.
When performing thermal recording, the shading correction unit 80D switches the switch 92c to the b side, and reads the initial correction condition stored in the first memory 92a and the difference stored in the second memory 92b. . Both are multiplied and multiplied by the multiplier 92d, and the correction condition is calculated from the multiplied data. The shading correction unit 80D performs shading correction using this.

As described above, the reading device 88 connected to the recording apparatus 10 cannot read image data with high accuracy and high density in terms of cost and device size.
Therefore, it is preferable that the image data read by the reading device 88 is used as image data for each pixel by averaging, linear interpolation, or the like as only low-frequency component image data.

The recording apparatus 10 according to the present invention may be configured not only to set the shading correction conditions described above, but also to set density correction conditions (calibration) using the reading device 88 and the image processing device 80. Good.
That is, image data of a chart on which a plurality of density image patterns are formed for setting density correction conditions is stored (or generated) in the pattern generation unit 81, and a predetermined number of thermal recordings are performed. After that, or when the user gives an instruction to reset the density correction condition, the pattern generation unit 81 outputs image data of a chart for setting the density correction condition, and the image processing apparatus 80 performs a predetermined process. And output to the memory 82, and a density correction chart is recorded on the thermal material A in the same manner as the above-described shading correction.
This chart is read by the reading device 88 and similarly A / D converted and stored in the memory 92 as image data for setting density correction conditions. The gradation correction unit 80B uses this image data to re-set the density correction conditions. Set. Thereafter, the gradation correction unit 80B converts the image data into image data corresponding to the thermal recording using the density correction condition.
The density correction condition setting method may be a known method, and examples thereof include a method of creating a conversion curve (conversion table) using a conversion algorithm.

  Furthermore, in the recording apparatus 10 according to the present invention, the aperture 96 of the reading device 88 may be made sufficiently small so that the thermal image recorded by the reading device 88 can be read and the sharpness can be measured.

The recording apparatus 10 described above includes a reading unit including a light source 86 and a reading device 88, an A / D converter 90, and a memory 92 inside the apparatus main body. The invention is not limited to this, and as shown in FIG. 4, a configuration having a reading unit 100 outside the main body of the recording apparatus 10 may be employed.
The reading unit 100 shown in FIG. 4 has the same configuration as the reading unit 20 in various respects, such as the configuration of the reading device 88, and therefore, the same members are denoted by the same reference numerals, and the following description is different. Mainly.

In the reading unit 100, a pair of conveyance rollers 104 and 104 that convey the heat-sensitive material A in the direction of arrow c in the figure are arranged in the housing 102, and a light source 86 is placed between the pair of conveyance rollers, and a conveyance path of the heat-sensitive material A A reading device 88 is disposed at each of the opposed positions, and an A / D converter 90 and a memory 92 are connected to the reading device 88, and a shading correction unit 80D of the main body of the recording device 10 is connected to the main body. It is configured integrally with.
Further, the reading device 88 is configured to be moved in a direction orthogonal to the conveying direction by the conveying roller pair 104, 104 by a moving means (not shown) as in the example shown in FIG. .
Further, a carry-in port 102 a and a discharge port 102 b are formed at positions corresponding to the transport path of the transport roller pair 104, 104 of the housing 102.

  Similar to the above-described example, in the example shown in FIG. 4, after performing a predetermined number of thermal recordings or when the user gives an instruction to reset the shading correction condition, the pattern generating unit 81 performs the shading correction condition. Is output to the image processing device 80 and stored in the memory 82. This chart is similarly recorded on the heat sensitive material A and discharged to the tray 72.

Next, the operator takes out the heat-sensitive material A on which the shading correction chart is recorded from the tray 72, matches the main scanning direction of the heat-sensitive material A with the moving direction of the reading device 88, and enters the housing 102 from the carry-in entrance 102a. insert.
Reading of the following chart and setting of correction conditions are basically the same as in the above example, detected by a sensor (not shown) or the like, and the conveyance roller pair 104, 104 rotates to pinch and convey the thermal material A, When the portion where the chart is recorded is conveyed to a reading position by the reading device 88, the reading device 88 starts moving and reads the chart while stopping or conveying the heat sensitive material A. This image data is A / D converted by the A / D converter 90 and stored in the memory 92, and the shading correction unit 80D resets the correction conditions using this image data.

The image recording apparatus of the present invention has been described in detail above. However, the present invention is not limited to the above examples, and various improvements and modifications may be made without departing from the scope of the present invention. It is.
For example, the illustrated apparatus performs image recording on a transparent heat-sensitive material A (heat-sensitive film), reads transmitted light, and sets shading correction conditions. If the recording material is not transparent, Similar to the reading of a normal reflection document, the shading correction condition may be set by reading the reflected light of the chart.

It is a conceptual diagram of an example using the image recording apparatus of the present invention for a thermal recording apparatus. FIG. 2 is a conceptual diagram of a recording unit of the thermal recording apparatus shown in FIG. It is a conceptual diagram of the reading means of the thermal recording apparatus shown by FIG. It is a conceptual diagram of another example in which the image recording apparatus of the present invention is used in a thermal recording apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 (Thermal image) Recording apparatus 14 Loading part 16 Supply conveyance means 18 Recording part 20,100 Reading part 22 Discharge part 24 Magazine 26 Cover body 28 Housing 30 Insertion slot 32 Guide plate 34 Guide roll 36 Stop member 40 Suction cup 42 Conveyance means 44 Conveying guide 48 Endless belt 50 Nip roller 52 Regulating roller pair 56 Cleaning roller pair 58, 62 Guide 60 Platen roller 63, 64, 104 Conveying roller pair 66 Thermal head 68 Support member 72 Tray 74 Discharge port 76 Cooling fan 80 Image processing device 81 Pattern Generator 82 Memory 84 Recording control device 86 Light source 88 Reading device 90 A / D converter 92 Memory 94 Lens 96 Aperture 98 Sensor 102 Housing A Heat sensitive (recording) material

Claims (9)

An image processing unit that receives image data from an external image data supply source, and performs image processing including at least shading correction on the image data to obtain image data for recording;
Output means for outputting image data of an image for setting shading correction conditions;
An image recording unit that performs image recording in accordance with image data output from the image processing unit or output unit;
Reading means for reading an image recorded by the image recording unit;
Based on the reading result obtained by reading the image for setting the shading correction condition by the reading unit, the first shading correction condition by the reading unit is calculated, and the first shading correction condition is already calculated. A second shading correction condition used for the shading correction in the image processing unit is calculated from data obtained by multiplying the initial shading correction condition and the difference by calculating a difference with respect to the set initial shading correction condition. And an image recording apparatus.   The image recording apparatus according to claim 1, wherein the first shading correction condition is calculated using only a low frequency component from an image reading result for setting the shading correction condition.   A low density image and a high density image are formed as an image for setting the shading correction condition, and a high frequency component is extracted from the low density image among the read results of the image for setting the shading correction condition. The image recording apparatus according to claim 1, wherein low frequency components are respectively extracted from a high density image and the first shading correction condition is calculated. A first memory storing the initial shading correction condition;
A second memory for storing the difference,
The setting means obtains the multiplied data by multiplying the initial shading correction condition stored in the first memory and the difference stored in the second memory, and from the multiplied data The image recording apparatus according to claim 1, wherein the second shading correction condition is set.   The image recording apparatus according to claim 1, wherein a mask size for image reading by the reading unit is 200 μm to 1 mm.   The image for setting the shading correction condition is read a plurality of times by the reading means at different positions in a direction orthogonal to the direction of occurrence of shading, and the first shading correction condition is calculated using the read result. The image recording apparatus according to any one of 1 to 5. The image recording unit is for recording an image on a transparent recording material,
The reading means includes a light source, an imaging lens, an aperture, and a sensor, or includes an LED or laser light source and a sensor, and detects the transmitted light of the recording material. The image recording apparatus according to claim 1, wherein an image recorded on the recording material is read.   The output unit outputs a density correction image for further setting a density correction condition, and the image recording unit is further based on the image data of the density correction image output from the output unit. The density correction condition in the image processing unit is set according to any one of claims 1 to 7, wherein the density correction image is recorded on a recording material, and a density correction condition in the image processing unit is set based on a reading result of the density correction image by the reading unit. Image recording device.   The image recording apparatus according to claim 1, wherein sharpness is measured from a result of reading the image by the reading unit.

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