JP2019028080A - Imaging unit - Google Patents

Abstract

To stably image a subject and a colorimetry reference chart.SOLUTION: An imaging unit 30 includes: a prescribed box-shaped frame body 32 in which, on a bottom face 32a opposing to a subject, an opening portion 32c for imaging the subject and a reference chart KC simultaneously imaged with the subject imaged through the opening portion 32c and providing a prescribed color reference are provided side by side in a prescribed direction of a main scanning direction indicated by an arrow A; an image sensor portion 34 for receiving reflection light from the subject opposing to the opening portion 32c and reflection light from the reference chart KC, and simultaneously imaging the subject and the reference chart KC; and an illumination light source 37 arranged at a position in which reflection light incident on the image sensor portion 34 of the reflection light of emission light to the subject and the reference chart KC becomes out of a regular reflection area.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an imaging unit, a color measurement device, an image forming apparatus, a color measurement system, and a color measurement method.

  Image forming devices such as color ink jet image forming devices and color electrophotographic image forming devices are offset by advertising media and pamphlets that require relatively high print quality but high image quality as image quality improves. It is also used for printing.

  In offset printing that requires high image quality, the color of the printed matter requested by the customer may differ from the color of the print output result that is actually printed out by the image forming apparatus.

  Usually, the customer confirms the color of the printed matter on the display and places an order for printing. However, each image forming apparatus has a color reproduction characteristic specific to each model, which is different from the color confirmed on the display. May result in printing.

  Therefore, conventionally, a technique for performing color reproduction using a color space that does not depend on a device such as a display or an image forming apparatus, such as a Lab color space or an xyz color space, has been used.

  The image forming apparatus controls the amount of color material and the like in order to output a specified color. For example, in an ink jet image forming apparatus, the output color is controlled by controlling the amount of ink discharged from the ink head by calculating and controlling the amount of ink discharged and the printing pattern. In the electrophotographic image forming apparatus, the output color is controlled by controlling the amount of toner adhering to the photoreceptor, the amount of laser beam, and the like.

  However, the amount of the color material, for example, the ink discharge amount of the ink jet image forming apparatus varies depending on the state of the nozzle of the head, the viscosity of the ink, the variation of the discharge drive elements (piezo elements, etc.), Variation in color reproducibility occurs. Further, the ink ejection amount of the ink jet type image forming apparatus changes with time in one image forming apparatus or varies for each image forming apparatus. In other words, variations in the color reproduction of the image occur.

  Therefore, conventionally, in an image forming apparatus, color adjustment processing is performed in order to suppress output variations due to characteristics unique to the device and to improve output reproducibility with respect to input. In this color adjustment processing, for example, first, an image of a reference color patch (reference color patch image) is actually output by the image forming apparatus, and the reference color patch image is measured by the color measurement device. Then, a color conversion parameter is generated based on the difference between the colorimetric value of the reference color patch image measured by the colorimetry device and the colorimetric value of the corresponding reference color in the standard color space, and the color conversion parameter is Set in the image forming apparatus. After that, when outputting an image according to the input image data, the image forming apparatus performs color conversion on the input image data based on the set color conversion parameter, and after color conversion is performed. By recording and outputting an image based on the image data, an output of an image with high color reproducibility can be achieved by suppressing output variations due to characteristics unique to the device.

  In this conventional color adjustment processing, a spectral colorimeter is widely used as a color measuring device for measuring a reference color patch image, and the spectral colorimeter can obtain a spectral reflectance for each wavelength. Therefore, highly accurate colorimetry can be performed. However, since the spectrocolorimeter is an expensive device equipped with a large number of sensors, it is desired to perform highly accurate color measurement using a cheaper device.

  Conventionally, reference colorimetric means for measuring a reference color chart in advance in order to obtain color reference values as RGB data, and an object including the reference color chart and a color-measurement object are imaged simultaneously or separately. Color image input means for obtaining data, image extraction means for extracting RGB data of the reference color chart and RGB data of the color to be measured from RGB data obtained by the color image input means, and the image extraction means The difference between the RGB data of the reference color chart obtained in step 1 and the RGB data of the reference color chart obtained by the reference color measurement means is obtained, and at least the RGB data of the color to be measured is corrected using this difference. There has been proposed a colorimetric device characterized by comprising a calculation means (see Patent Document 1). In this conventional technique, a reference color chart to be compared with the subject is placed near the subject to be colorimetric, and the subject and the reference color chart are simultaneously imaged by a color video camera as a color image input means. In addition, it is disclosed that the RGB data of the subject is corrected using the RGB data of the reference color chart obtained by imaging, and the RGB data of the subject is converted into color values in the standard color space.

  However, with the technique described in Patent Document 1, it is difficult to keep the positional relationship among the subject, the reference color chart, and the color video camera constant, and the imaging conditions fluctuate every time imaging is performed, so that stable imaging can be performed. There is no fear.

  The present invention has been made in view of the above, and an object thereof is to provide an imaging unit, a color measurement device, an image forming apparatus, a color measurement system, and a color measurement method capable of performing stable imaging.

  In order to achieve the above object, an imaging unit according to the present invention includes a two-dimensional image sensor that images a subject through an opening, a lens disposed between the two-dimensional image sensor and the opening, and the lens. The reference chart is arranged so as to be arranged in the order of the opening, the illumination light source, and the reference chart when viewed in the optical axis direction.

  According to the present invention, the subject and the color reference chart can always be imaged with a stable positional relationship.

1 is a schematic perspective view of an image forming apparatus to which an embodiment of the present invention is applied. The top view of a carriage part. FIG. The top view of an imaging unit. AA arrow sectional drawing of the imaging unit of FIG. BB arrow sectional drawing of the imaging unit of FIG. CC sectional view of the imaging unit of FIG. The top view of a reference | standard chart. FIG. 3 is a block diagram of a main part of the image forming apparatus. The block block diagram of an imaging unit and a colorimetry control part. Explanatory drawing of the acquisition process of the reference | standard colorimetry value and imaging reference RGB value from a reference | standard sheet, and a reference value linear transformation matrix acquisition process. The figure which shows an example of the image data which imaged the reference | standard chart and the imaging target simultaneously. The figure which shows an example of an initial reference RGB value. Explanatory drawing of a colorimetry process. Explanatory drawing of the linear conversion matrix production | generation process between reference | standard RGB. The figure which shows the relationship between an initial reference | standard RGB value and the reference | standard RGB value at the time of colorimetry. Explanatory drawing of a basic colorimetry process. FIG. 18 is a diagram illustrating basic color measurement processing continued from FIG. 17. The top view of the imaging unit provided with the light-shielding member. AA arrow sectional drawing of the imaging unit of FIG. The BB arrow sectional drawing of the imaging unit of FIG. The top view of the other imaging unit provided with the light-shielding member. AA arrow sectional drawing of the imaging unit of FIG. 22 which showed regular reflection light. BB arrow sectional drawing of the imaging unit of FIG. CC sectional view of the imaging unit of FIG. AA arrow sectional drawing of the imaging unit of FIG. 23 which shows the light irradiation state which does not contain the regular reflection light to an opening part. The back view of another light-shielding member. 1 is a system configuration diagram of an image forming system. The top view of the imaging unit of 2nd Example. AA arrow sectional drawing of the imaging unit of FIG. The perspective view of the board | substrate and light guide of the imaging unit of FIG. The perspective view which shows the other example of the arrangement structure of a light guide. The perspective view which shows the further another example of arrangement | positioning structure of a light guide. The front sectional view of the imaging unit which is not provided with the optical path length changing member.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, since the Example described below is a suitable Example of this invention, various technically preferable restrictions are attached | subjected, However, The range of this invention is unduly limited by the following description. However, not all the configurations described in the present embodiment are essential constituent elements of the present invention.

  Note that “Lab (Lab value)” described below means, for example, the CIELAB (CIE 1976 L * a * b *) color space. Hereinafter, for convenience of explanation, “L * a * b *” is simply expressed as “Lab”.

  1 to 28 are diagrams showing a first embodiment of an imaging unit, a color measurement device, an image forming apparatus, a color measurement system, and a color measurement method according to the present invention. FIG. 1 is a schematic perspective view of an image forming apparatus 1 to which a first embodiment of a color device, an image forming apparatus, a color measurement system, and a color measurement method are applied.

  In FIG. 1, the image forming apparatus 1 has a main body housing 2 disposed on a main body frame 3. A main guide rod 4 and a sub guide rod 5 are stretched in the main body housing 2 in the main scanning direction indicated by a double arrow A in FIG. The main guide rod 4 supports the carriage 6 so as to be movable. The carriage 6 is provided with a connecting piece 6 a that engages with the sub guide rod 5 to stabilize the posture of the carriage 6.

  In the image forming apparatus 1, an endless belt-like timing belt 7 is disposed along the main guide rod 4. The timing belt 7 is stretched between the driving pulley 8 and the driven pulley 9. The drive pulley 8 is rotationally driven by the main scanning motor 10. The driven pulley 9 is disposed in a state in which a predetermined tension is applied to the timing belt 7. The driving pulley 8 is rotationally driven by the main scanning motor 10 to rotate and move the timing belt 7 in the main scanning direction according to the rotation direction.

  The carriage 6 is connected to a timing belt 7, and is reciprocated in the main scanning direction along the main guide rod 4 when the timing belt 7 is rotationally moved in the main scanning direction by the drive pulley 8.

  In the image forming apparatus 1, the cartridge unit 11 and the maintenance mechanism unit 12 are accommodated at both end positions in the main scanning direction in the main body housing 2. In the cartridge unit 11, cartridges that respectively store yellow (Y), magenta (M), cyan (C), and black (K) inks are replaceably stored. Each cartridge of the cartridge unit 11 is connected to recording heads 20y, 20m, 20c, and 20k (see FIG. 2) of the corresponding color of the recording head 20 mounted on the carriage 6 by a pipe (not shown). Each cartridge supplies ink to the corresponding recording heads 20y, 20m, 20c, and 20k through pipes. In the following description, the recording heads 20y, 20m, 20c, and 20k are collectively referred to as the recording head 20.

  As will be described later, the image forming apparatus 1 moves on the platen 14 (see FIG. 2) in the sub-scanning direction (arrow B direction in FIG. 1) perpendicular to the main scanning direction while moving the carriage 6 in the main scanning direction. By ejecting ink onto the recording medium P that is intermittently conveyed, an image is recorded on the recording medium P.

  That is, the image forming apparatus 1 of the present embodiment intermittently conveys the recording medium P in the sub-scanning direction, and moves the carriage 6 in the main scanning direction while the conveyance of the recording medium P in the sub-scanning direction is stopped. While moving, ink is ejected from the nozzle array of the recording head 20 mounted on the carriage 6 onto the recording medium P on the platen 14 to form an image on the recording medium P.

  The maintenance mechanism unit 12 performs cleaning of the ejection surface of the recording head 20, capping, ejection of unnecessary ink, and the like to discharge unnecessary ink from the recording head 20 and maintain the reliability of the recording head 20. .

  The image forming apparatus 1 is provided with a cover 13 that can open and close a conveyance portion of the recording medium P. By opening the cover 13 during maintenance of the image forming apparatus 1 or when a jam occurs, maintenance work inside the main body housing 2 or work such as removal of the jam recording medium P can be performed.

  As shown in FIG. 2, the carriage 6 carries recording heads 20y, 20m, 20c, and 20k. The recording heads 20y, 20m, 20c, and 20k are connected to the corresponding color cartridges of the cartridge unit 11 by pipes, and discharge the corresponding color inks to the opposing recording medium P, respectively. That is, the recording head 20y is yellow (Y) ink, the recording head 20m is magenta (M) ink, the recording head 20c is cyan (C) ink, and the recording head 20k is black (K) ink. Discharge each.

  The recording head 20 is mounted on the carriage 6 so that its discharge surface (nozzle surface) faces downward (recording medium P side) in FIG. 1, and discharges ink onto the recording medium P.

  In the image forming apparatus 1, an encoder sheet 15 is disposed in parallel with the timing belt 7, that is, the main guide rod 4 over at least the movement range of the carriage 6. An encoder sensor 21 that reads the encoder sheet 15 is attached to the carriage 6. The image forming apparatus 1 controls the movement of the carriage 6 in the main scanning direction by controlling the driving of the main scanning motor 10 based on the reading result of the encoder sheet 15 by the encoder sensor 21.

  As shown in FIG. 3, the recording heads 20 mounted on the carriage 6 are each composed of a plurality of nozzle rows 20y, 20m, 20c, and 20k. An image is formed on the recording medium P by ejecting ink from the nozzle rows onto the recording medium P conveyed on the platen 14. In order to ensure a wide width of an image that can be formed on the recording medium P by a single scan of the carriage 6, the image forming apparatus 1 has an upstream recording head 20 and a downstream recording head 20 mounted on the carriage 6. ing. Further, in order to improve the black printing speed, the recording heads 20k that are twice as many as the recording heads 20y, 20m, and 20c that discharge color inks are mounted on the carriage 6. Further, the recording heads 20y and 20m are arranged adjacent to each other in the main scanning direction so that the colors are aligned in the reciprocating operation of the carriage 6 so that the color does not change between the forward path and the backward path. Has been. The arrangement of the recording heads 20y, 20m, 20c, and 20k of the recording head 20 is not limited to the arrangement shown in FIG.

  As shown in FIG. 2, an imaging unit (imaging device) 30 is attached to the carriage 6. The imaging unit 30 images the subject in order to measure the subject (colorimetric object) during color adjustment processing described later.

  The imaging unit 30 is a plan view of FIG. 4, FIG. 5 is a cross-sectional view taken along the line AA of FIG. 4, and FIG. 6 is a cross-sectional view taken along the line BB of FIG. As shown in FIG. 7, which is a cross-sectional view, a square box-shaped frame body 32 whose surface on the side of the substrate 31 is open is fixed to the substrate 31 by a fastening member 33. The substrate 31 is fixed to the carriage 6 shown in FIG. The frame body 32 is not limited to a rectangular box shape, and may be, for example, a cylindrical box shape having a bottom surface portion 32a in which openings 32b and 32c are formed, an elliptical cylinder box shape, or the like. .

  The imaging unit 30 is provided with an image sensor unit 34 at the center of the surface of the substrate 31 on the frame 32 side. The image sensor unit (sensor unit) 34 includes a two-dimensional image sensor 35 such as a CCD (Charge Coupled Device) sensor or a CMOS (Complementary Metal Oxide Semiconductor) sensor and a lens 36.

  In the imaging unit 30, the frame 32 has a lower surface of a surface portion (hereinafter referred to as a bottom surface portion) 32 a opposite to the substrate 31 facing the recording medium P on the platen 14 with a predetermined distance d. In the state, it is attached to the carriage 6. The bottom surface (opposite surface) 32a has a substantially rectangular opening 32b and an opening 32c in the main scanning direction centered on the center line Lo, with the specular reflection absorbing bottom surface 32aa having a predetermined width interposed therebetween. Is formed. The bottom surface portion 32aa may be subjected to a predetermined surface treatment that absorbs specularly reflected light.

  As will be described later, the gap d is preferably small in consideration of the focal length with respect to the two-dimensional image sensor 35. From the relationship with the flatness of the recording medium P, the size is set such that the lower surface of the frame 32 and the recording medium P do not contact each other, for example, about 1 mm to 2 mm.

  As will be described later, the opening 32c includes a reference color patch KP (see FIG. 10) of the reference sheet KS (see FIG. 10) that is an imaging target (subject) formed on the recording medium P, and a colorimetric adjustment sheet CS. This is used to image the colorimetric adjustment color patch CP (see FIG. 5) of (see FIG. 5). The opening 32c may be at least large enough to capture all images to be imaged. Since there is a gap d between the frame 32 and the object to be imaged, it is formed in an opening state slightly larger than the size of the imaging area of the object to be imaged in consideration of the shadow generated around the opening 32c.

  The opening 32b is formed with a recess 32d having a predetermined width along the periphery of the opening 32b on the surface of the recording medium P side. A reference chart KC is detachably set in the recess 32d. A holding plate 32e that covers the surface of the reference chart KC on the recording medium P side and is held by the reference chart KC in the recess 32d is detachably attached to the recess 32d in the opening 32b of the frame 32. The opening 32b is closed by the reference chart KC and the holding plate 32e. The holding plate 32e has a smooth flat surface on the recording medium P side.

  The reference chart KC is compared with the reference color patch KP of the reference sheet KS and the imaged colorimetric value of the colorimetric adjustment color patch CP of the colorimetric adjustment sheet CS that is the image pickup object in the color adjustment process. Photographed at the same time as the reference color patch KP and the colorimetric adjustment color patch CP. In other words, the imaging unit 30 passes through the opening 32c provided in the bottom surface portion 32a of the frame body 32, so that the reference color patch KP of the reference sheet KS outside the frame body 32 and the color measurement adjustment color patch CP of the color measurement adjustment sheet CS can be changed. Simultaneously with the imaging, the color patch on the reference chart KC attached to the recess 32d formed around the opening 32b of the bottom surface 32a of the frame 32 is imaged as a comparison target. Note that in the imaging unit 30, the two-dimensional image sensor 35 sequentially scans pixels to read an image. Therefore, strictly speaking, the reference color patch KP of the reference sheet KS and the color measurement adjustment color patch CP of the color measurement adjustment sheet CS and the reference chart KC are not read simultaneously, but the reference color patch KP and the color measurement within one frame. Since the images of the adjustment color patch CP and the reference chart KC can be acquired, this is expressed as simultaneous acquisition.

  As shown in FIG. 8, the reference chart KC has a plurality of reference color patch rows Pa to Pd, dots for color measurement on the inner surface (upper surface) of the frame 32, as shown in FIG. A diameter measurement pattern row Pe, a distance measurement line lk, and a chart position specifying marker mk are formed.

  The color measurement patch rows Pa to Pd include a patch row Pa in which YMC primary color patches are arranged in gradation order, a patch row Pa in which RGB secondary color patches are arranged in gradation order, and a gray color. There are a patch array (achromatic color gradation pattern) Pc in which scale patches are arranged in gradation order, and a patch array Pd in which tertiary color patches are arranged. The dot diameter measurement pattern row Pe is a geometric shape measurement pattern row in which circular patterns having different sizes are arranged in order of size.

  The distance measurement line lk is formed as a rectangular frame surrounding the color measurement patch rows Pa to Pd and the dot diameter measurement pattern row Pe. The chart position specifying markers mk are provided at the positions of the four corners of the distance measuring line lk, and are markers for specifying each patch position.

  A colorimetric control unit 106 (see FIGS. 9 and 10), which will be described later, specifies the distance measurement line lk and the chart position specifying markers mk at the four corners from the image data of the reference chart KC acquired from the imaging unit 30. The position of the reference chart KC and the position of each pattern are specified.

  Each patch constituting the reference color patch rows Pa to Pd for colorimetry is a standard color space Lab using a spectroscope BS (see FIG. 11) in the same manner as a reference color patch KP of a reference chart KC described later. Color values (Lab values) in the color space are measured in advance. This colorimetric value becomes a reference value for colorimetry of the colorimetric adjustment color patch CP of the colorimetric adjustment sheet CS described later.

  The configuration of the colorimetric patch rows Pa to Pd arranged in the reference chart KC is not limited to the arrangement example shown in FIG. 7, and any patch row can be used. As long as possible, a patch capable of specifying a wide color range may be used, and the YMCK primary color patch row Pa and the gray scale patch row Pc may be used for the ink used in the image forming apparatus 1. It may be composed of patches of colorimetric values. In addition, the RGB secondary color patch row Pa of the reference chart KC may be composed of patches of colorimetric values that can be developed with ink used in the image forming apparatus 1, and further, colorimetrics such as JapanColor. A reference color chart having a predetermined value may be used.

  In this embodiment, a reference chart having a patch array in the form of a general patch (color chart) is used, but the reference chart does not necessarily have such a patch array. The reference chart may have a configuration in which a plurality of colors that can be used for colorimetry are arranged so that their positions can be specified.

  The reference chart KC is disposed in a concave portion 32d formed on the outer periphery of the surface on the recording medium P side of the opening 32b formed in the bottom surface portion 32a of the frame body 32. For this reason, the two-dimensional image sensor 35 of the image sensor unit 34 can capture an image with the same focal length as the imaging target such as the recording medium P.

  Further, the reference chart KC is detachably set in the recess 32d formed on the outer periphery of the surface on the recording medium P side of the opening 32b formed in the bottom surface portion 32a of the frame 32, and the recording medium P The side surface is detachably held by a holding plate 32e that is detachably attached to the recess 32d. For this reason, even if dust or the like entering the frame 32 adheres to the surface of the reference chart KC, it can be attached again after removing the holding plate 32e and the reference chart KC and cleanly cleaning the reference chart KC. The measurement accuracy of the reference chart KC can be improved.

  4 to 7 again, the image pickup unit 30 is on the center line Lo in the sub-scanning direction passing through the center of the image sensor unit 34, and is located in the sub-scanning direction from the center of the image sensor unit 34, respectively. A pair of illumination light sources 37 are disposed on the substrate 31 at positions spaced at equal intervals by a fixed amount. As the illumination light source 37, an LED (Light Emitting Diode) or the like is used. The illumination light source 37 is disposed on the center line Lo, that is, directly above the bottom surface portion 32aa for absorbing regular reflection. The bottom surface portion 32aa for absorbing regular reflection is formed with a width wider than the regular reflection area SA of the illumination light source 37, as shown in FIG.

  Further, in the imaging unit 30, the arrangement conditions of the opening 32 c of the imaging region and the reference chart KC are arranged substantially symmetrically with respect to the center line Lo connecting the center of the lens 36 and the illumination light source 37. For this reason, the imaging conditions of the two-dimensional image sensor 35 can be made line-symmetric and the same, and the accuracy of color adjustment processing and color measurement processing of the two-dimensional image sensor 35 using the reference chart KC can be improved.

  The image forming apparatus 1 of the present embodiment is configured as a block as shown in FIG. The image forming apparatus 1 includes a CPU (Central Processing Unit) 101, a ROM (Read Only Memory) 102, a RAM (Random Access Memory) 103, a main scanning driver 104, a recording head driver 105, a colorimetric control unit 106, and a paper transport unit 107. And the sub-scan driver 108 and the like, and the recording head 20, the encoder sensor 21, and the imaging unit 30 and the like mounted on the carriage 6 as described above.

  The ROM 102 stores programs such as a basic program and a color adjustment processing program as the image forming apparatus 1 and necessary system data. The CPU 101 executes basic processing as the image forming apparatus 1 by controlling each unit of the image forming apparatus 1 while using the RAM 103 as a work memory based on a program in the ROM 102. Further, the CPU 101 executes color adjustment processing at the time of image formation based on the colorimetric values obtained by the colorimetric processing in the colorimetric control unit 106 based on the RGB values captured by the imaging unit 30.

  In the control of the carriage 6 and the paper transport unit 107, the CPU 101 controls the driving of the main scanning driver 104 based on the encoder value from the encoder sensor 21 to control the movement of the carriage 6 in the main scanning direction. Further, the CPU 101 controls driving of a paper transport unit 107 such as a sub-scan motor and a transport roller (not shown) via a sub-scan driver 108. Further, the CPU 101 controls the ink ejection timing and the ink ejection amount by the recording head 20 via the recording head driver 105. Further, the CPU 101 controls the lighting drive of the illumination light source 37 of the imaging unit 30 via the color measurement control unit 106.

  As described above, the imaging unit 30 generates a color measurement value for color adjustment that accurately reproduces the color of image data when recording and outputting an image to a color intended by the user, as described later. The color measurement color patch CP formed by the recording head 20 on the recording medium P is imaged at the time of color measurement, and the captured RGB values are output to the CPU 101. In the present embodiment, the colorimetric control unit 106 is configured separately from the imaging unit 30, but the colorimetric control unit 106 may be configured integrally with the imaging unit 30. For example, a control circuit that functions as the colorimetric control unit 106 may be mounted on the substrate 31 of the imaging unit 30.

  The imaging unit 30 and the colorimetric control unit 106 are configured as a block as shown in FIG. The imaging unit 30 includes the illumination light source 37 and the image sensor unit 34, and also includes an image processing unit 110, an interface unit 111, and the like. In the present embodiment, the image processing unit 110 is configured separately from the image sensor unit 34. However, the two-dimensional image sensor 35 of the image sensor unit 34 may have the function of the image processing unit 110. . The image processing unit 110 includes an A / D conversion unit 112, a shading correction unit 113, a white balance correction unit 114, a γ correction unit 115, and an image format conversion unit 116.

  The imaging unit 30 outputs analog RGB image data obtained by the image sensor unit 34 simultaneously capturing the subject and the reference chart KC to the image processing unit 110. The image processing unit 110 performs necessary image processing on the analog RGB image data sent from the image sensor unit 34 and outputs it to the colorimetry control unit 106.

  The A / D conversion unit 112 of the image processing unit 110 digitally converts analog RGB image data input from the image sensor unit 34 and outputs the converted data to the shading correction unit 113.

  The shading correction unit 113 corrects the error of the image data caused by the illuminance unevenness of the illumination light from the illumination light source 37 with respect to the imaging range of the image sensor unit 34 with respect to the RGB image data input from the A / D conversion unit 112. And output to the white balance correction unit 114.

  The white balance correction unit 114 corrects the white balance of the RGB image data after the shading correction, and outputs the corrected data to the γ correction unit 115.

  The γ correction unit 115 corrects the image data input from the white balance correction unit 114 so as to compensate for the linearity of the sensitivity of the image sensor unit 34 and outputs the corrected data to the image format conversion unit 116.

  The image format conversion unit 116 converts the image data after γ correction into an arbitrary format, and outputs it to the colorimetry control unit 106 via the interface unit 111.

  The interface unit 111 is used for the imaging unit 30 to acquire various setting signals, timing signals, and light source drive signals sent from the colorimetry control unit 106 and to send image data from the imaging unit 30 to the colorimetry control unit 106. Interface.

  The color measurement control unit 106 includes a frame memory 121, a timing signal generation unit 122, a light source drive control unit 123, a calculation unit 124, and a nonvolatile memory 125. The calculation unit 124 includes a color measurement value calculation unit 126. Yes.

  The frame memory 121 is a memory that temporarily stores the image data sent from the imaging unit 30, and outputs the stored image data to the calculation unit 124.

  As shown in FIG. 11, the non-volatile memory 125 includes Lab values that are colorimetric values of the colorimetric results of a plurality of reference color patches KP arrayed on the reference sheet KS by the spectroscope (colorimetry device) BS. And at least one of the XYZ values (both Lab and XYZ values in FIG. 11) are stored as reference colorimetric values in the memory table Tb1 of the nonvolatile memory 125 in correspondence with the patch numbers.

  Further, the image forming apparatus 1 sets the reference sheet KS on the platen 14 in a state where the reference colorimetric values are stored in the memory table Tb1 of the nonvolatile memory 125 and in the initial state of the image forming apparatus 1. Then, the movement of the carriage 6 is controlled, and the same reference color patch KP as that read by the spectroscope BS of the reference sheet KS is read by the imaging unit 30. The image forming apparatus 1 stores the read imaging reference RGB values in the memory table Tb1 of the nonvolatile memory 125 in association with the patch number, that is, in correspondence with the reference colorimetric value. In addition, the imaging unit 30 captures each patch of the reference chart KC to acquire an RGB value, and uses the RGB value of each patch of the reference chart KC as an initial reference RGB value RdGdBd under the control of the calculation unit 124. Stored in the memory table Tb1 of the memory 125.

  When the reference colorimetric value, the imaging reference RGB value, and the initial reference RGB value RdGdBd are stored in the nonvolatile memory 125, the colorimetric value calculation unit 126 uses the XYZ values of the reference colorimetric values stored in the nonvolatile memory 125. And a reference value linear conversion matrix for mutual conversion of a pair of imaging reference RGB values, that is, a pair of XYZ values and imaging reference RGB values having the same patch number. The colorimetric value calculation unit 126 stores the calculated reference value linear conversion matrix in the nonvolatile memory 125.

  The image forming apparatus 1 executes the above process in the initial state, registers the reference colorimetric value, the imaging reference RGB value, and the initial reference RGB value RdGdBd, which are the execution results, in the memory table Tb1 of the nonvolatile memory 125, A value linear transformation matrix is calculated and stored in the nonvolatile memory 125.

  Further, as will be described later, the image forming apparatus 1 according to the present exemplary embodiment includes a color measurement adjustment color patch CP and a frame as a subject formed on the recording medium P by the recording head 20 that changes with time during color adjustment processing. The reference chart KC disposed inside the body 32 is simultaneously imaged by the image sensor unit 34, and image data including the colorimetric adjustment color patch CP and the reference chart KC is output to the colorimetry control unit 106. The color measurement control unit 106 uses the color measurement adjustment color patch CP captured by the image sensor unit 34 during the color adjustment processing acquired from the imaging unit 30 as a reference color patch (hereinafter referred to as an initial reference color patch) of the reference sheet KS. After being read by the imaging unit 30 and converted into the initial reference RGB values RdGdBd of the patches Pa to Pe of the reference chart KC read and stored at the same time, the colorimetric adjustment color patch CP of the initial reference RGB value RdGdBd is converted to the initial reference RGB value RdGdBd. Of these, a portion having linearity is taken out and subjected to linear conversion to perform colorimetric processing for obtaining a colorimetric value.

  That is, the arithmetic unit 124 controls the operation of the colorimetric control unit 106, and the colorimetric value calculation unit 126 executes the colorimetric processing and outputs the colorimetric values that are the results of the colorimetric processing to the CPU 101. To do. The CPU 101 performs color adjustment processing on the image data using the colorimetric values, and controls the recording head 20 based on the color adjustment processed image data, thereby forming an image with improved color reproducibility.

  The image forming apparatus 1 of this embodiment includes a ROM, an EEPROM (Electrically Erasable and Programmable Read Only Memory), an EPROM, a flash memory, a flexible disk, a CD-ROM (Compact Disc Read Only Memory), and a CD-RW (Compact Disc Rewritable). A color measurement program for executing the color measurement method of this embodiment recorded on a computer-readable recording medium such as a DVD (Digital Versatile Disk), an SD (Secure Digital) card, or an MO (Magneto-Optical Disc). It is constructed as an image forming apparatus 1 equipped with a color measuring device that executes a color measuring method that realizes color reproducibility described later at low cost and stably by reading and introducing it into the ROM 102 or the nonvolatile memory 125 or the like. . This color measurement program is a computer-executable program written in a legacy programming language such as assembler, C, C ++, C #, Java (registered trademark) or an object-oriented programming language, and is stored in the recording medium. Can be distributed.

  Next, the operation of this embodiment will be described. The image forming apparatus 1 of the present embodiment executes a color measurement method that realizes color reproducibility inexpensively and stably.

  As shown in FIG. 11, the image forming apparatus 1 according to the present embodiment uses the spectroscope BS to calculate the color measurement results of a plurality of reference color patches arranged and formed on the reference sheet KS, among Lab values and XYZ values. , At least one of them is stored as a reference colorimetric value corresponding to the patch number in the memory table Tb1 of the nonvolatile memory 125.

  Further, when the image forming apparatus 1 is in a state where the reference colorimetric values are stored in the nonvolatile memory 125 in the memory table Tb1 and the image forming apparatus 1 is in an initial state due to manufacture, overfall, or the like, The reference sheet KS is set on the platen 14 of the image forming apparatus 1, the movement of the carriage 6 is controlled, and the same reference patch read by the spectroscope BS of the reference sheet KS is read by the imaging unit 30. At the same time, the image forming apparatus 1 images each patch (initial reference color patch) of the reference chart KC arranged inside the frame 32 as shown in FIG.

  When the reference patch of the reference sheet KS and each patch of the reference chart KC are imaged by the imaging unit 30, the imaging reference RGB which is an RGB value obtained by processing the image data obtained by imaging the reference patch of the reference sheet KS by the image processing unit 110 As shown in FIG. 11, the calculation unit 124 causes the memory table Tb1 of the nonvolatile memory 125 to correspond to the patch number, that is, the reference colorimetric value. Store correspondingly. Further, the arithmetic unit 124 reads the initial reference color patch of the reference chart KC and processes the initial reference RGB value RdGdBd, which is the RGB value processed by the image processing unit 110, as shown in FIG. To store.

  The calculation unit 124 calculates an average value for each predetermined region, for example, a region (color measurement target region) indicated by a broken line in FIG. 12 among the image data of the initial reference color batch of the reference chart KC read by the imaging unit 30. The initial reference RGB value RdGdBd is calculated. When the initial reference RGB value RdGdBd is calculated by averaging a large number of pixels in the colorimetric object region in this way, the influence of noise can be reduced and the bit resolution can be improved. FIG. 13B is a scatter diagram in which the initial reference RGB value RdGdBd is plotted, and FIG. 13A is a reference Lab value Ldaddbd and XYZ value obtained by converting the initial reference RGB value RdGdBd into Lab values. The reference XYZ value xdydzd also indicates a state registered in the nonvolatile memory 125.

  When the reference colorimetric value, the imaging reference RGB value, and the initial reference RGB value RdGdBd are stored in the nonvolatile memory 125, the colorimetric value calculation unit 126 uses the XYZ values of the reference colorimetric values stored in the nonvolatile memory 125. And a reference value linear conversion matrix for mutual conversion of a pair of imaging reference RGB values, that is, a pair of XYZ values and imaging reference RGB values having the same patch number. The colorimetric value calculation unit 126 stores the calculated reference value linear conversion matrix in the nonvolatile memory 125.

  In this state, the CPU 101 performs main scanning movement control of the carriage 6, transport control of the recording medium P by the paper transport unit 107, and drive control of the recording head 20 based on externally input image data, print settings, and the like. Thus, while intermittently transporting the recording medium P, the ink ejection from the recording heads 20y, 20m, 20c, and 20k of the recording head 20 is controlled, and an image is recorded and output on the recording medium P.

  At this time, the amount of ink discharged from the recording heads 20y, 20m, 20c, and 20k may change depending on the characteristics unique to the device, changes with time, and the like. When the ink discharge amount changes, an image is formed with a color different from the color of the image intended by the user, and the color reproducibility deteriorates.

  Therefore, the image forming apparatus 1 executes color adjustment processing for obtaining a colorimetric value and performing color adjustment based on the colorimetric value at a predetermined color adjustment processing timing.

  That is, at the color adjustment processing timing, the image forming apparatus 1 forms a plurality of color patches (colorimetric adjustment color patches) CP on the recording medium P by the recording head 20 as shown in FIG. Recorded and output as a sheet CS. This color measurement adjustment sheet CS is obtained by forming and outputting a color measurement adjustment color patch CP, which is a plurality of color patches for color measurement adjustment, by the recording head 20. The color measurement adjustment sheet CS is formed with a color measurement adjustment color patch CP reflecting the output characteristics at the color adjustment processing timing of the image forming apparatus 1, particularly the output characteristics of the recording head 20. Note that the color patch data of the color measurement adjustment color patch CP is stored in advance in the nonvolatile memory 125 or the like.

  Then, as will be described later, the image forming apparatus 1 uses the RGB values obtained by imaging the plurality of color measurement adjustment color patches CP of the color measurement adjustment sheet CS as color measurement target RGB values (color measurement RGB values). A color object RGB value is converted into an initial reference RGB value RdGdBd, and among the reference colorimetric values registered in the memory table Tb1 of the nonvolatile memory 125, the initial reference RGB value RdGdBd is converted. Select a reference colorimetric value that is close in distance (neighboring reference colorimetric value). The image forming apparatus 1 obtains a colorimetric value for converting the colorimetric target RGB value to the selected neighborhood reference colorimetric value, and records the colorimetric value based on the image data after performing color conversion based on the colorimetric value. An image is output by the head 20. Thereby, the color reproducibility of the image formed by the image forming apparatus 1 is improved.

  Therefore, as shown in FIG. 14, the image forming apparatus 1 is in a state in which the colorimetric adjustment sheet CS is set on the platen 14 or when the colorimetric adjustment sheet CS is recorded, without discharging the platen 14. The plurality of color measurement adjustment color patches CP of the color measurement adjustment sheet CS on the platen 14 are imaged by the imaging unit 30 while controlling the movement of the carriage 6 while being held on the platen 14. The patch of the chart KC is imaged. When the color measurement adjustment color patch CP of the color measurement adjustment sheet CS and the patch of the reference chart KC are simultaneously imaged by the imaging unit 30, the image processing unit 110 displays the image data of the color measurement adjustment color patch CP of the color measurement adjustment sheet CS. After the necessary image processing is performed on the patch image data of the reference chart KC, the image data (RGB value) of the color measurement adjustment color patch CP of the color measurement adjustment sheet CS is converted into the color measurement target RGB value, that is, The device-dependent signal depending on the device and the image data (RGB value) of the patch of the reference chart KC are sent to the colorimetry control unit 106 as the colorimetric reference RGB value RdsGdsBds. As shown in FIG. 14, the colorimetric control unit 106 temporarily stores it in the frame memory 121 (step S11).

  The colorimetric control unit 106 uses the colorimetric value RGB value stored in the frame memory 121 by the colorimetric value calculation unit 126 of the calculation unit 124 to initialize the colorimetric object to be initialized using a reference RGB linear conversion matrix to be described later. Conversion into RGB values RsGsBs (steps S12 and S13).

  The calculation unit 124 of the color measurement control unit 106 executes the basic color measurement process described later by using the converted initialization color measurement target RGB value RsGsBs as the color measurement target RGB value (step S14), and converts the Lab color measurement value. Obtain (step S15).

  In the image forming apparatus 1 according to the present exemplary embodiment, the colorimetric value calculation unit 126 of the calculation unit 124 obtains the reference RGB linear conversion matrix as illustrated in FIGS. 15 and 16.

  That is, as shown in FIG. 15, the calorimetric value calculation unit 126 of the calculation unit 124 captures the patch of the reference chart KC at the same time when the imaging unit 30 captures the reference color patch KP of the reference sheet KS at the initial stage. When the initial reference RGB value RdGdBd stored in the nonvolatile memory 125 and the color measurement adjustment color patch CP of the color measurement adjustment sheet CS are imaged by the imaging unit 30 during color measurement, the patch of the reference chart KC is simultaneously captured. Then, the colorimetric reference RGB value RdsGdsBds stored in the nonvolatile memory 125 is read from the nonvolatile memory 125. The colorimetric value calculation unit 126 obtains a reference inter-RGB linear conversion matrix for converting the colorimetric reference RGB value RdsGdsBds to the initial reference RGB value RdGdBd, and stores the obtained reference inter-RGB linear conversion matrix in the nonvolatile memory 125.

  That is, in FIG. 16, the points indicated by white dots in FIG. 16A are points where the initial reference RGB values RdGdBd are plotted in the rgb space, and the filled points are the colorimetric reference RGB values RdsGdsBds as rgb. This is a point plotted in space. As can be seen from FIG. 16A, the value of the colorimetric reference RGB value RdsGdsBds varies from the value of the initial reference RGB value RdGdBd. These fluctuation directions in the rgb space are substantially the same as indicated by arrows in FIG. 16B, but the direction of deviation differs depending on the hue. As described above, the reason why the RGB values fluctuate even when the patches of the same reference chart KC are imaged includes a change with time of the illumination light source 37 and a change with time of the two-dimensional image sensor 35.

  In this way, the colorimetric values are measured using the colorimetric target RGB values when the colorimetric adjustment color patch CP of the colorimetry adjustment sheet CS is imaged in a state that changes when the same reference chart KC patch is imaged. Therefore, an error may occur in the colorimetric value by the amount of variation.

  In view of this, the image forming apparatus 1 according to the present exemplary embodiment uses the estimation method such as the least square method between the initial reference RGB value RdGdBd and the colorimetric reference RGB value RdsGdsBds to initially set the colorimetric reference RGB value RdsGdsBds. A reference RGB linear conversion matrix to be converted into a reference RGB value RdGdBd is obtained. Also, the image forming apparatus 1 uses the reference RGB linear conversion matrix to image the color measurement adjustment color patch CP of the color measurement adjustment sheet CS by the imaging unit 30 and store the color measurement stored in the nonvolatile memory 125. The target RGB value is converted into an initialization colorimetric target RGB value RsGsBs. Then, the image forming apparatus 1 executes a basic color measurement process described later using the converted initialization color measurement target RGB value RsGsBs as a color measurement target RGB value, and acquires a Lab color measurement value.

  This reference RGB linear transformation matrix may be not only the first order but also a higher order nonlinear matrix. When the nonlinearity is high between the rgb space and the XYZ space, conversion accuracy can be improved by using a higher-order matrix.

  The imaging unit 30 captures images of the reference color patch KP of the reference sheet KS as the subject and the color measurement adjustment color patch CP of the color measurement adjustment sheet CS through the opening 32c formed in the bottom surface portion 32a. At the same time, the patch of the reference sheet KS disposed in the opening 32c of the bottom surface portion 32a of the frame body 32 is imaged. As a result, the reference color patch KP of the reference sheet KS and the colorimetric adjustment color patch CP of the colorimetry adjustment sheet CS can be imaged with the same positional relationship as the subject, and the stable state You can take an image.

  Further, the reference color patch KP of the reference sheet KS as the subject through the opening 32c, the colorimetry adjustment color patch CP and the reference chart KC of the colorimetry adjustment sheet CS are illuminated as shown in FIGS. The light source 37 is arranged so as to be out of the regular reflection area SA. The incident light from the reference color patch KP, the colorimetric adjustment color patch CP, and the reference chart KC to the two-dimensional image sensor 35 does not include regular reflection light. In FIG. 6, the regular reflection area SA is regularly reflected only on the bottom surface 32 aa between the opening 32 b where the reference chart KC is arranged and the opening 32 c for imaging the colorimetric adjustment color patch CP and the like. The state where the area SA exists is shown. FIG. 7 shows a state in which regular reflection occurs at the bottom surface portion 32aa.

  Therefore, it is possible to prevent the image of the reference color patch KP, the colorimetry adjustment color patch CP, and the reference chart KC captured by the image sensor unit 34 from including a defective image due to the specularly reflected light of the illumination light source 37. The color can be measured.

  In the imaging unit 30, the illumination light that irradiates the imaging surface of the recording medium P through the opening 32c and the illumination light that irradiates the reference chart KC are illumination light from the same illumination light source 37 and have the same illumination conditions. Thus, the reference chart KC and the imaging surface of the recording medium P can be imaged simultaneously. Further, two illumination light sources 37 are arranged on the center line Lo which is a substantially intermediate position between the reference chart KC and the recording medium P, and two symmetrically arranged on the center line Lo with respect to the lens 36. For this reason, the reference chart KC and the imaging area of the recording medium P can be illuminated uniformly under substantially the same conditions.

  Further, in the imaging unit 30, the arrangement conditions of the opening 32 c of the imaging region and the reference chart KC are arranged substantially symmetrically with respect to the center line Lo connecting the center of the lens 36 and the illumination light source 37. For this reason, the imaging conditions of the two-dimensional image sensor 35 can be made line-symmetric and the same, and the accuracy of color adjustment processing and color measurement processing of the two-dimensional image sensor 35 using the reference chart KC can be improved.

  Then, the image forming apparatus 1 obtains the initial colorimetric target RGB value RsGsBs as described above and sets it as the colorimetric target RGB value, as shown in FIGS. 17 and 18, the memory table Tb1 of the nonvolatile memory 125 as shown in FIGS. Among the reference colorimetric values registered in (1), a reference colorimetric value (neighboring reference colorimetric value) that is close in distance to the colorimetric value converted to the colorimetric object RGB value is selected. The image forming apparatus 1 performs basic colorimetry processing for obtaining a colorimetric value for converting the colorimetric target RGB value into the selected neighborhood reference colorimetric value, and after performing color conversion based on the colorimetric value An image is output by the recording head 20 based on the image data. Thereby, the color reproducibility of the image formed by the image forming apparatus 1 is improved.

  That is, as shown in FIG. 17, the image forming apparatus 1 captures the color measurement adjustment color patch CP of the color measurement adjustment sheet CS, obtains the initial color measurement target RGB value RsGsBs as described above, and determines the color measurement target RGB. When stored in the nonvolatile memory 125 as a value (step S21), the reference value linear conversion matrix is used (step S22), converted into a first XYZ value (step S23), and stored in the nonvolatile memory 125 (step S22). S24). For example, in FIG. 17, the colorimetric value calculation unit 126 converts the colorimetric target RGB values (3, 200, 5) of the imaging unit 30 into the first XYZ values (first colorimetric values) of (20, 80, 10). And stored in the nonvolatile memory 125.

  The colorimetric value calculation unit 126 converts the first XYZ value into a first Lab value (first colorimetric value) by referring to the memory table Tb1 of the nonvolatile memory 125 or using a known conversion formula. (Step S25), stored in the nonvolatile memory 125 (Step S26). For example, in FIG. 17, the colorimetric value calculation unit 126 converts the first XYZ value (20, 80, 10) into the first Lab value (75, −60, 8) that is the imaged colorimetric value.

  Next, the colorimetric value calculation unit 126 searches for the reference colorimetric values (Lab values) of the color patches of the plurality of colors in the memory table Tb1 stored in the nonvolatile memory 125, as indicated by the Lab space in FIG. Then, a set of color patches (neighboring color patches) that are close in distance to the first Lab value in the Lab space is selected from the reference colorimetric values (Lab values) (step S27). For example, in the Lab space diagram of FIG. 17, 60 color patches are selected and plotted on the Lab space. As a method for selecting a patch having a short distance, for example, the distance between the first Lab value and all points in the reference colorimetric values (Lab values) of a plurality of color patches is calculated, and the first Lab that is the first colorimetric value is calculated. A method of selecting a reference Lab value (a reference Lab value with hatching in FIG. 17) of a color patch whose distance is close to the value can be applied.

  Next, as shown in FIG. 17, the colorimetric value calculation unit 126 refers to the memory table Tb1, and sets the imaging reference RGB values paired with the first Lab value of the selected set, that is, the first Lab of the selected set. The combination of the imaging reference RGB value (selected RGB value) and the reference XYZ value having the same patch number is selected (step S28). The colorimetric value calculation unit 126 obtains a selected RGB value linear conversion matrix for conversion between the combination of the imaging reference RGB and the reference XYZ of the selected combination (selected set) using the least square method, and the obtained selection. The RGB value linear conversion matrix is stored in the nonvolatile memory 125 (step S29).

  The colorimetric value calculation unit 126 uses the selected RGB value linear conversion matrix to calculate the colorimetry target RGB values obtained by imaging the colorimetry adjustment color patches CP of the colorimetry adjustment sheet CS that is the colorimetry target by the imaging unit 30. A second XYZ value that is a second colorimetric value is obtained (step S30). The colorimetric value calculation unit 126 converts the second XYZ value into the second Lab value using a known conversion formula (step S31), and obtains it as the final colorimetric value (step S32).

  The colorimetric value calculation unit 126 performs image adjustment based on the image data that has been color-converted using the obtained colorimetric value, and drives the recording head 20 based on the image data that has undergone image adjustment to form an image.

  In other words, the image forming apparatus 1 according to the present embodiment captures and acquires a plurality of color measurement adjustment color patches CP of the color measurement adjustment sheet CS reflecting the output characteristics of the recording head 20 at the color adjustment processing timing. The first Lab value when the reference sheet KS is imaged in the initial state using the reference value linear conversion matrix is obtained as the colorimetric target RGB values. The image forming apparatus 1 selects a set of patches with a reference Lab value that is close in distance to the first Lab value in the Lab space from among the reference Labs of a plurality of color patches registered in the memory table Tb1. The colorimetric RGB values corresponding to the selected reference Lab value are converted into Lab values using the selected RGB value linear conversion matrix to obtain Lab colorimetric values. Then, the colorimetric value calculation unit 126 performs image adjustment based on the image data subjected to color conversion using the obtained colorimetric value, and drives the recording head 20 based on the image data subjected to image adjustment to form an image. To do.

  As described above, in the image forming apparatus 1 according to the present embodiment, the imaging unit 30 captures the opening 32c for imaging the subject and the subject imaged through the opening 32c on the opposite surface facing the subject. And a reference chart KC for providing a predetermined color reference, and a predetermined box-shaped frame 32 provided side by side in a predetermined direction, reflected light from a subject facing the opening 32c, and the reference chart KC. An image sensor unit (sensor unit) 34 that receives reflected light and images the subject and the reference chart KC simultaneously, and is incident on the image sensor unit 34 of the reflected light of the irradiation light on the subject and the reference chart KC. And an illumination light source 37 disposed at a position where the reflected light is outside the regular reflection region.

  Accordingly, the specularly reflected light from the illumination light source 37 attached in the frame 32 is incident on the image sensor unit 34 so as to overlap the subject outside the frame 32 and the image of the reference chart KC in the frame 32. Therefore, the subject and the reference chart KC can always be imaged with a stable positional relationship.

  Further, in the imaging unit 30, the illumination light source 37 is disposed at a position where the specular reflection region overlaps the bottom surface portion 32aa which is an intermediate region between the imaging region of the subject that has passed through the opening 32c and the imaging region of the reference chart KC. Has been.

  Therefore, with a simple and inexpensive configuration, the specularly reflected light from the illumination light source 37 overlaps the subject outside the frame 32 and the image of the reference chart KC in the frame 32 and is incident on the image sensor unit 34. Therefore, the subject and the reference chart KC can be imaged inexpensively and always in a stable positional relationship.

  Further, in the imaging unit 30, a pair of illumination light sources 37 are disposed at symmetrical positions in the length direction with respect to the center in the length direction of the bottom surface portion 32 aa that is an intermediate region having a predetermined length. .

  Therefore, it is possible to prevent the specularly reflected light of the illumination light source 37 from entering the image sensor unit 34 overlapping the subject outside the frame 32 and the image of the reference chart KC inside the frame 32. Further, the illumination light can be evenly applied to the subject and the reference chart KC, and the subject and the reference chart KC can be imaged with high accuracy and always in a stable positional relationship.

  In the above description, the imaging unit 30 uses the pair of illumination light sources 37 as the subject through the opening 32c, the reference color patch KP of the reference sheet KS, the colorimetric adjustment color patch CP of the colorimetry adjustment sheet CS, and By arranging the reference chart KC so as to be out of the regular reflection area SA of the illumination light source 37, the image captured by the image sensor unit 34 is prevented from being affected by regular reflection of the illumination light source 37. The configuration for preventing the influence of regular reflection of the illumination light source 37 is not limited to the above configuration. For example, a light shielding member 51 that shields regular reflection light may be provided as in the imaging unit 50 shown in FIGS. Here, FIG. 19 is a plan view of the imaging unit 50, FIG. 20 is a sectional view taken along the line AA of the imaging unit 50 in FIG. 19, and FIG. 21 is a sectional view taken along the line BB of the imaging unit 50 in FIG. FIG. 19 to 21, the same components as those of the imaging unit 30 of FIGS. 4 to 7 are denoted by the same reference numerals, and detailed description thereof is omitted.

  That is, the light shielding member 51 extends directly to the center line Lo in the sub-scanning direction passing through the center of the image sensor unit 34 at a substantially intermediate position between the image sensor unit 34 and the bottom surface portion 32a. In the existing state, the frame body 32 is disposed across the opposing side surfaces in the sub-scanning direction. The light shielding member 51 holds the illumination light source 37a by attaching the illumination light source 37a to the center position in the sub-scanning direction, that is, the surface on the bottom surface portion 32a side immediately below the center of the image sensor unit 34. .

  As shown in FIG. 21, the light shielding member 51 is necessary for shielding the incident on the image sensor 34 of the specularly reflected light emitted from the illumination light source 37a toward the bottom surface portion 32a and reflected by the bottom surface portion 32a. Thus, the width does not hinder the reflected light from the reference chart KC and the reflected light from the subject through the opening 32c from entering the image sensor unit 34.

  In the imaging unit 50, the optical path length changing member 52 is disposed in the optical path between the recording medium P and the two-dimensional image sensor 35 through the opening 32c in a state where the opening 32c is closed. As the optical path length changing member 52, a transmissive member having a refractive index n (n is an arbitrary value) is used. As shown in FIG. 20, the optical path length changing member 52 has an outer shape larger than the opening 32 c and is disposed in the frame body 32. The fixing position of the optical path length changing member 52 is not limited to the position of the opening 32 c inside the frame body 32. As long as it is in the optical path between the opening 32c and the two-dimensional image sensor 35, for example, the position on the imaging surface side of the frame 32, the position inside the frame 32 and away from the opening 32c may be used. . When the light passes through the optical path length changing member 52 having the refractive index n, the light is extended in accordance with the refractive index n of the optical path length changing member 52, and the two-dimensional image sensor 35 is in a state where the image is lifted. The amount C of the rising of the image can be obtained by the following equation (1), where Lp is the length of the optical path length changing member 52.

C = Lp (1-1 / n) (1)
Further, the focal length L of the focal plane of the imaging unit 50 other than the reference chart KC, that is, the focal length to the surface of the recording medium P imaged through the optical path length changing member 52 and the opening 32c is expressed by the following equation (2). Can be sought.

L = Lc + Lp (1-1 / n) (2)
Here, Lc is the distance between the top of the lens 36 on the imaging target side and the reference chart KC, and n is the refractive index of the optical path length changing member 52.

  Therefore, for example, when the refractive index n of the optical path length changing member 52 is 1.5, L = Lc + Lp (1-1 / 1.5) = Lc + Lp (1/3), and the length of the optical path length changing member 52 The optical path length can be increased by about 1/3 of Lp. If Lp = 9 [mm], L = Lc + 3 [mm], and the imaging position of the reference chart KC and the focal position of the imaging surface of the recording medium P can be matched. The imaging surface of the recording medium P can be set in a conjugate relationship.

  The illumination light that irradiates the reference chart KC and the illumination light that irradiates the imaging surface of the recording medium P through the optical path length changing member 52 and the opening 32c are illumination light from the same illumination light source 37a. For this reason, the imaging unit 50 can simultaneously image the imaging surface of the reference chart KC and the recording medium P under the same illumination conditions as in the case of the imaging unit 30. The illumination light source 37 a is disposed on the center line Lo, which is a substantially intermediate position between the reference chart KC and the recording medium P, and is attached to the light shielding member 51 at a position directly below the lens 36. For this reason, the reference chart KC and the imaging area of the recording medium P can be illuminated uniformly under substantially the same conditions.

  Further, in the imaging unit 50, the arrangement conditions of the opening 32c of the imaging region and the reference chart KC are arranged substantially symmetrically with respect to the center line Lo connecting the center of the lens 36 and the illumination light source 37a. For this reason, the imaging conditions of the two-dimensional image sensor 35 can be made line-symmetric and the same, and the accuracy of color adjustment processing and color measurement processing of the two-dimensional image sensor 35 using the reference chart KC can be improved.

  As described above, in the imaging unit 50, the illumination light source 37a is located at a predetermined distance in the vertical direction from the image sensor unit 34 toward the bottom surface 32a that is the opposite surface, and emits irradiation light in the direction of the bottom surface 32a. The light shielding member 51 is disposed so as to shield the regular reflection light of the illumination light emitted from the illumination light source 37a from entering the image sensor unit 34.

  Therefore, it is possible to reliably prevent the specularly reflected light of the illumination light source 37a from entering the image sensor unit 34, and it is possible to always image the subject and the reference chart KC with high accuracy with a stable positional relationship.

  Further, in the imaging unit 50, the illumination light source 37 a is attached to the surface of the light shielding member 51 on the bottom surface portion 32 a side.

  Therefore, it is possible to reliably prevent the regular reflection light of the illumination light source 37a from being incident on the image sensor unit 34 with a simple configuration, and the subject and the reference chart KC are always inexpensive and have a stable positional relationship with high accuracy. An image can be taken.

  In this case, the imaging unit 50 changes the optical path length as shown in FIGS. 22 to 27 when the focal length of the subject such as the reference chart KC and the recording medium P to the image sensor unit 34 can be ignored with accuracy. The member 52 may not be provided. Also in this case, as shown in FIG. 26, the light shielding member 51 to which the illumination light source 37a is attached reflects the reflected light (regular reflected light) of the regular reflection area SA of the light emitted from the illumination light source 37a to the bottom surface portion 32a. Has a necessary and sufficient width to be incident on the image sensor unit 34.

  In this way, it is possible to prevent the regular reflection light from affecting the captured image even more inexpensively and reliably.

  Further, as described above, the light shielding member 51 is not limited to a plate-shaped member having a predetermined width that is stretched between the inner side surfaces of the frame body 32 in the sub-scanning direction. For example, as shown in FIG. 27, the light shielding member 53 has the entire inside of the frame 32 parallel to the substrate 31 at a substantially intermediate position where the illumination light source 37a between the image sensor unit 34 and the bottom surface 32a of the frame 32 is disposed. The aperture 53b necessary and sufficient to make the reflected light from the reference chart KC incident on the image sensor 34 and the reflected light from the subject through the opening 32c are imaged. An opening 53c that is necessary and sufficient to enter the sensor portion 34 is formed. The light shielding member 53 is a light shielding member portion located between the opening 53b and the opening 53c, and an illumination light source 37a is attached at a position directly below the image sensor portion 34.

  The light shielding member 53 may be formed integrally with the frame body 32, or may be attached to the frame body 32 by a method such as adhesion or fixation.

  Further, in the above description, the color measurement process is performed by the color measurement control unit 106 of the image forming apparatus 1, but the color measurement process need not be executed inside the image forming apparatus 1. For example, as illustrated in FIG. 28, as an image forming system (colorimetry system) 200, an image forming apparatus 210 is connected to an external apparatus 220, and image data captured by the image forming apparatus 210 is captured by the external apparatus 220. The external device 220 performs color adjustment processing with colorimetric processing, and outputs the color-adjusted image data to the image forming device 210. The image forming device 210 receives the image data from the external device 220. The image may be formed based on the above.

  That is, the image forming apparatus 210 includes an engine 211, an operation display unit 212, an I / F unit 213, other I / F units 214, and the like, and each unit is connected by a bus 215. In addition, the external device 220 can use, for example, a computer having a normal hardware configuration and software configuration, and includes a color adjustment program including a color measurement program that executes a color adjustment process accompanying the color measurement process of the present invention as software. The color adjustment process accompanied by the colorimetric process is executed by introducing. The external device 220 includes a CPU 221, a memory unit 222, an image processing unit 223, a communication I / F unit 224, an I / F unit 225, and the like, and each unit is connected by a bus 226. The memory unit 222 includes a ROM 227, a RAM 228, a hard disk (HDD) 229, and the like.

  The image forming apparatus 210 is connected to the external apparatus 220 via a line 230 by an I / F unit 213. The line 230 is a dedicated line, a network such as a LAN (Local Area Network), the Internet, and the like, and is wired. Or wireless.

  The image forming apparatus 210 forms and outputs an image on a recording medium with the engine 211 based on the image data sent from the external apparatus 220 under the control of the external apparatus 220. The engine 211 forms an image on a recording medium by an ink ejection method or the like, and the operation display unit 212 includes various operation keys and a display such as an LCD (Liquid Crystal Display), which are necessary for the operation of the image forming apparatus 210. Various operations are performed by the operation keys. The operation display unit 212 displays and outputs various information notified from the image forming apparatus 210 to the user. The other I / F unit 214 is used for connecting an expansion unit.

  The engine 211 includes a carriage that moves in the main scanning direction as described in the above embodiment. The imaging unit 30 is attached to the carriage. The image forming apparatus 210 forms the color measurement adjustment color patch CP on the recording medium based on the color patch data of the color measurement adjustment color patch CP sent from the external apparatus 220 under the control of the CPU 221 of the external apparatus 220. Thus, the colorimetric adjustment sheet CS is generated. The image forming apparatus 210 reads the color measurement adjustment color patch CP of the generated color measurement adjustment sheet CS with the imaging unit, and transmits it to the external device 220 via the I / F unit 213.

  The external device 220 stores in the hard disk 229 or the ROM 227 an image formation control program for controlling the operation of the image forming apparatus 210, a color adjustment program for performing color adjustment processing accompanying colorimetric processing of the present invention, and necessary data. The CPU 221 controls the image forming apparatus 210 based on a program in the ROM 227 or the hard disk 229, thereby executing basic processing as the image forming apparatus 210 and executing color adjustment processing accompanying colorimetric processing of the present invention.

  The hard disk 229 stores the above program and various data necessary for executing the color adjustment processing, in particular, the colorimetry of the plurality of reference color patches KP arranged on the reference sheet KS described in the above embodiment. Of the resulting Lab value and XYZ value, at least one of the reference color patch KP of the reference sheet KS is read by the image pickup unit of the image forming apparatus 210. Table and selected RGB value linear conversion matrix, initial reference RGB value RdGdBd of each color patch of the reference chart KC read simultaneously with the reference sheet KS, and reference read simultaneously when the colorimetric adjustment color patch CP of the colorimetry adjustment sheet CS is read Reference RGB value RdsGdsBds at the time of color measurement of the reference patch of chart KC and at the time of color measurement Reference RGB between linear transformation matrix to convert the quasi RGB values RdsGdsBds the initial reference RGB value RdGdBd is stored.

  The communication I / F unit 224 is connected to an image processing apparatus such as a scanner apparatus, a composite apparatus, or another external apparatus via a line such as a network, and receives image data that causes the image forming apparatus 210 to output an image.

  The image processing unit 223 performs various image processes necessary for forming and outputting the image data with the engine 211 of the image forming apparatus 210.

  As described above, the CPU 221 controls the operation of the image forming apparatus 210 and also executes a colorimetric process executed by the calculation unit 124 of the colorimetry control unit 106, in particular, the colorimetric value calculation unit 126. , Color adjustment is performed on the image data based on the colorimetric value, and the image data is output to the image forming apparatus 210.

  In the image forming system 200 of FIG. 28, the operation of the image forming apparatus 210 is controlled by the external apparatus 220. However, the image forming apparatus 210 itself includes a controller such as a CPU. The external device 220 may execute only the color measurement process for which the controller controls and obtains the color measurement value, or only the color adjustment process including the color measurement process.

  As described above, when color adjustment processing including color measurement processing or color measurement processing is executed at least by an external device of the image forming apparatus 210, the color reproducibility can be appropriately improved at low cost even in the inexpensive image forming apparatus 210. it can.

  FIGS. 29 to 34 are diagrams showing a second embodiment of the imaging unit, the color measuring device, the image forming apparatus, the color measuring system, and the color measuring method according to the present invention. FIG. 29 is a plan view of an image pickup unit 300 mounted on an image forming apparatus to which a second embodiment of the image pickup unit, colorimetric apparatus, image forming apparatus, colorimetric system, and colorimetric method of the present invention is applied. 30 is a cross-sectional view taken along arrow AA in FIG. This embodiment is applied to an image forming apparatus similar to the image forming apparatus 1 of the first embodiment. Further, the present invention is applied to an imaging unit 300 similar to the imaging unit 30 shown in FIGS. Therefore, in the description of the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the same reference numerals are used and the description thereof is omitted or omitted. Simplify.

  29 to 31, the imaging unit 300 is attached to the carriage 6 of the image forming apparatus 1. Similar to the imaging unit 30 of the first embodiment, the imaging unit 300 images the subject in order to measure the subject (colorimetric object) during the color adjustment process.

  The imaging unit 300 is provided with an image sensor unit 34 at the center of the surface of the substrate 31 on the frame 32 side. As described above, the image sensor unit (sensor unit) 34 includes a two-dimensional image sensor 35 such as a CCD sensor or a CMOS sensor and a lens 36.

  In the imaging unit 300, the frame 32 is in a state where the lower surface of the bottom surface portion (opposing surface) 32 a opposite to the substrate 31 faces the recording medium P on the platen 14 with a predetermined distance d. Attached to the carriage 6. The bottom surface portion 32a is formed with an opening portion 32b and an opening portion 32c each having a substantially rectangular shape in the main scanning direction around the center line Lo, with the bottom surface portion 32aa for absorbing regular reflection having a predetermined width therebetween. Yes. The bottom surface portion 32aa may be subjected to a predetermined surface treatment that absorbs specularly reflected light.

  As described above, the opening 32c captures the reference color patch KP of the reference sheet KS and the colorimetric adjustment color patch CP of the colorimetry adjustment sheet CS, which are imaging targets (subjects) formed on the recording medium P. Used for.

  In the opening 32b, a concave portion 32d having a predetermined width is formed along the periphery of the opening 32b on the surface on the recording medium P side, and the reference chart KC is detachably set in the concave portion 32d. A holding plate 32e that covers the surface of the reference chart KC on the recording medium P side and is held by the recess 32d of the reference chart KC is detachably attached to the recess 32d of the opening 32b of the frame 32. The opening 32b is closed by the reference chart KC and the holding plate 32e. The holding plate 32e has a smooth flat surface on the recording medium P side. The reference chart KC is the same as described above. Similarly to the imaging unit 50 shown in FIGS. 19 to 21, the imaging unit 300 closes the opening 32c, and the optical path between the recording medium P and the two-dimensional image sensor 35 through the opening 32c. An optical path length changing member 52 having a refractive index n is disposed therein.

  In the imaging unit 300, the light guide 301 is disposed on the surface of the substrate 31 on the frame 32 side. The light guide 301 guides the illumination light emitted from one illumination light source 302 provided outside the frame 32 into the frame 32. The light guide 301 is on a center line Lo in the sub-scanning direction passing through the center of the image sensor unit 34 and one incident port 301 a located outside the frame 32, and from the center of the image sensor unit 34. It has a pair of exit ports 301b that open toward the bottom surface portion 32a at positions spaced apart by a predetermined amount in the scanning direction, and a light guide portion 301c that connects the entrance ports 301a and the exit ports 301b. The light guide part 301c is divided into two forks from a position near the entrance 301a and is connected to a pair of exits 301b. That is, the light exit 301b of the light guide 301 has a regular reflection area SA whose reference color patch KP of the reference sheet KS as a subject that has passed through the opening 32c, and the color measurement adjustment color patch CP of the color measurement adjustment sheet CS and Illumination light is emitted in a state of being located on the bottom surface portion 32aa deviating from the reference chart KC.

  The light guide 301 is made of a member having good light guide properties such as an optical fiber. The light guide portion 301c other than the entrance port 301a and the exit port 301b is formed or subjected to a light shielding process by a light shielding member that prevents light leakage to the outside and light incidence from the outside.

  In the imaging unit 300, an illumination light source (light source member) 302 is disposed at a position facing the entrance 301 a of the light guide 301. As the illumination light source 302, for example, an LED or the like is used. The type of light source (illumination light sources 37 and 302) is not limited to LEDs. For example, an organic EL or the like may be used as the light source. When organic EL is used as the light source, illumination light close to the spectral distribution of sunlight can be obtained, so that improvement in colorimetric accuracy can be expected. The illumination light source 302 is a support member (not shown) that can adjust the incident angle of the illumination light to the entrance 301a so that the same amount of illumination light is emitted from the pair of exits 301b, as indicated by arrows in FIG. Is attached.

  The light guide 301 guides the illumination light incident from the entrance 301a to the exit 301b through the light guide 301c, and emits the light from the exit 301b toward the bottom surface 32a of the frame 32.

  On the upper end surface of the frame 32, a recess 32f through which the light guide portion 301c of the light guide 301 can pass is formed. The light guide 301 is disposed in a state where the light guide 301c passes between the recess 32f and the substrate 31. Even if a light shielding member (not shown) for preventing external light from entering the frame 32 is provided between the substrate 32 and the recess 32f of the frame 32 through which the light guide portion 301c passes. Good.

  29 to 31, the light guide 301 is drawn from the outside of the frame 32 into the frame 32 through the recesses 32 f formed on the side surfaces of the frame 32, and the frame of the substrate 31 is removed. It is attached to the surface on the body 32 side. On the center line Lo, the exit port 301b is disposed in an open state just above the bottom surface portion 32aa between the opening portion 32b and the opening portion 32c where the reference chart KC is disposed. The arrangement configuration of the light guide 301 is not limited to the above arrangement configuration.

  For example, as shown in FIG. 32, the imaging unit 300 is directly above the bottom surface portion 32aa between the opening portion 32b and the opening portion 32c where the reference chart KC is disposed on the center line Lo. A pair of illumination windows 31 a is formed on the substrate 31 at a symmetrical position with the image sensor unit 34 interposed therebetween, and the light guide 301 in which the emission port 301 b is located in the illumination window 31 a is arranged so as to crawl the upper surface of the substrate 31. It may be. In this case, the light guide 301 is positioned on the upper surface, which is the surface opposite to the frame 32 of the substrate 31, and receives incident light from the illumination light source 302 disposed in the incident port 301a portion from the incident port 301a. Then, the light is irradiated into the frame 32 through the illumination window 31a of the substrate 31 from the emission port 301b. At this time, in the light guide 301, the emission port 301b is arranged at a position where the regular reflection area SA of the illumination light is emitted in a state where it becomes the bottom surface portion 32aa.

  The light guide 301 is not limited to a shape in which the entrance 301a and the pair of exits 301b are connected by a light guide 301c that is divided into two branches. For example, as shown in FIG. 33, the light guide 303 may be formed linearly on the center line Lo. In this case, the imaging unit 300 is on the center line Lo and is directly above the bottom surface portion 32aa between the opening portion 32b and the opening portion 32c where the reference chart KC is disposed, and the image sensor unit. A pair of illumination windows 31 a is formed on the substrate 31 at a symmetrical position with respect to 34. In the illumination window 31a, a pair of emission ports 303b formed on the surface on the substrate 31 side at both end positions of the linear light guide 303 are disposed, and the pair of emission ports 303b. Are connected by the light guide portion 303c. The light guide 303 has an entrance 303a on one end face in the longitudinal direction. An illumination light source 302 is disposed at a position facing the entrance port 303a. The light guide 303 has a function of equally dividing the illumination light incident from the illumination light source 302 into the entrance port 303a into a pair of exit ports 303b formed at both ends in the longitudinal direction and emitting the light from the exit port 303b. Have. The light guide 303 illuminates the frame 32 through the illumination window 31 a formed in the substrate 31 with the illumination light divided evenly. In the light guide 303, an emission port 303b is arranged at a position where the regular reflection area SA of the illumination light is emitted in a state where it becomes the bottom surface portion 32aa.

  Furthermore, in the above description, in the imaging unit 300, the optical path length changing member 52 is disposed in a state where the opening 32c is closed in the frame 32, but the distance between the subject to be imaged through the opening 32c and the reference chart KC. If the difference is within the focal depth of the lens 36, the optical path length changing member 52 may not be provided as shown in FIG.

  The imaging unit 300 of the present embodiment is used to image the reference chart KC and the subject when performing the colorimetric processing at an appropriate timing, like the imaging units 30 and 50 of the first embodiment. It is done.

  In the imaging unit 300, the exits 301b and 303b of the light guides 301 and 303 are positioned directly above the bottom surface part 32aa wider than the regular reflection area SA of the illumination light from the exits 301b and 303b. The chart KC and the subject are arranged at a position where the subject is illuminated under the same illumination condition. In addition, the light guides 301 and 303 divide the illumination light emitted from one illumination light source 302 uniformly into the emission ports 301b and 303b, and irradiate the reference chart KC and the subject from the emission ports 301b and 303b. Yes.

  As described above, in the image forming apparatus 1 according to the present exemplary embodiment, the imaging unit 300 uses, as an illumination light source, one illumination light source (light source member) 302 that emits illumination light, and illumination light emitted from the illumination light source 302. A light guide 301 that guides the light, and the light guide 301 receives the illumination light emitted from the illumination light source 302 and an image of the reflected light of the irradiation light to the subject and the reference chart KC. The entrance 301a and the exit 301b are connected to the exit 301b, which is arranged at a position where the reflected light incident on the sensor 34 is outside the regular reflection area SA and emits illumination light, and is shielded from the outside. And a light guide portion 301c for guiding the illumination light incident from the incident port 301a to the exit port 301b.

  Therefore, the imaging unit 300 can illuminate and image the reference chart KC and the subject while preventing regular reflection using the light guides 301 and 303 under the same illumination conditions. Images can be taken with high accuracy and colorimetry can be performed with high accuracy.

  In addition, in the light guide 301 of the imaging unit 300, one entrance 301a is disposed at a position for taking in illumination light emitted from the illumination light source 302, and the exit 301b is an imaging region of a subject through the opening 32c. A pair of illumination light beams are arranged at positions symmetrical to the longitudinal direction with respect to the center in the longitudinal direction of the bottom surface portion 32aa which is an intermediate region having a predetermined length between the imaging region of the reference chart KC and the reference chart KC In addition, the light guide unit 301c is connected to the incident port 301a and is separated in the middle to be connected to the pair of emission ports 301b.

  Therefore, the illumination light from one illumination light source 302 can be illuminated on the subject and the reference chart KC in a state closer to the same illumination condition, and color measurement can be performed with higher accuracy.

  Note that the imaging unit 300 of the present embodiment can be applied to the image forming system 200 of the above-described embodiment in the same manner as described above.

  The invention made by the present inventor has been specifically described based on the preferred embodiments. However, the present invention is not limited to that described in the above embodiments, and various modifications can be made without departing from the scope of the invention. It goes without saying that it is possible.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Main body case 3 Main body frame 4 Main guide rod 5 Sub guide rod 6 Carriage 6a Connection piece 7 Timing belt 8 Drive pulley 9 Driven pulley 10 Main scanning motor 11 Cartridge part 12 Maintenance mechanism part 13 Cover 14 Platen 20, 20y, 20m, 20c, 20k Recording head 21 Encoder sensor 30 Imaging unit 31 Substrate 31a Illumination window 32 Frame body 32a Bottom surface part 32b Opening part 32c Opening part 32d Concave part 32e Holding plate 32f Concave part 32aa Bottom part 33 Fastening member 34 Image sensor part 35 Two-dimensional image sensor 36 Lens 37 Illumination light source 50 Imaging unit 51 Light shielding member 52 Optical path length changing member 53 Light shielding member 37a Illumination light source 53b Opening 53c Opening 101 CPU
102 ROM
103 RAM
104 Main Scan Driver 105 Recording Head Driver 106 Colorimetry Control Unit 107 Paper Transport Unit 108 Sub Scan Driver 110 Image Processing Unit 111 Interface Unit 112 A / D Conversion Unit 113 Shading Correction Unit 114 White Balance Correction Unit 115 γ Correction Unit 116 Image Format Conversion unit 121 Frame memory 122 Timing signal generation unit 123 Light source drive control unit 124 Calculation unit 125 Non-volatile memory 126 Colorimetric value calculation unit 200 Image forming system 210 Image forming apparatus 211 Engine 212 Operation display unit 213 I / F unit 214 Others I / F unit 215 Bus 220 External device 221 CPU
222 Memory unit 223 Image processing unit 224 Communication I / F unit 225 I / F unit 226 Bus 227 ROM
228 RAM
229 Hard disk 230 Line 300 Imaging unit 301 Light guide 302 Illumination light source 301a Entrance 301b Exit 301c Light guide 303 Light guide 303a Entrance 303b Exit 303c Light guide Lo Center line KS Reference sheet KP Reference color patch CS Measurement Color adjustment sheet CP Color measurement adjustment color patch KC Reference chart Pa to Pd Reference color patch row Pe Pattern pattern for dot diameter measurement lk Distance measurement line mk Chart position specifying marker

JP-A-5-223642

Claims (1)

A two-dimensional image sensor for imaging a subject through an opening;
A lens disposed between the two-dimensional image sensor and the opening;
A reference chart that is arranged in the order of the opening, the illumination light source, and a reference chart when viewed in the optical axis direction of the lens, and is imaged by the two-dimensional image sensor;
An imaging unit comprising: