JP6652174B2 - Imaging unit, colorimetric device, image forming apparatus, colorimetric system, and colorimetric method - Google Patents

Description

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

  Image forming apparatuses such as a color ink jetting type image forming apparatus and a color electrophotographic image forming apparatus have a relatively small number of copies but are required to offset printing mediums and pamphlets, etc., which require a high image quality as the image quality is improved. It is also being used for printing.

  In offset printing requiring high image quality, the color of a printed material requested by a customer may be different from the color of a printout result actually printed out by the image forming apparatus.

  Usually, the customer checks the color of the printed matter on the display and places an order for printing, but each image forming apparatus has a model-specific color reproduction characteristic and differs from the color confirmed on the display. Printing results may occur.

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

  Then, the image forming apparatus controls the amount of the color material and the like in order to output the designated color. For example, in an ink-jet type image forming apparatus, the output color is controlled by calculating and controlling the ink ejection amount, the print pattern, and the like, and controlling the ink ejection amount from the ink head. 2. Description of the Related Art In an electrophotographic image forming apparatus, output color is controlled by controlling the amount of toner adhering to a photoreceptor, the amount of a laser beam, and the like.

  However, the amount of the color material, for example, the amount of ink ejected from the ink-jet type image forming apparatus varies depending on the state of the nozzles of the head, the variation in ink viscosity, the variation in ejection driving elements (piezo elements, etc.), and the like. The color reproducibility varies. Further, the ink ejection amount of the ink ejection type image forming apparatus changes over time in one image forming apparatus, or varies from one image forming apparatus to another. This causes variations in the color reproduction of the image.

In order to achieve the above object, an imaging unit according to the present invention includes: a two-dimensional image sensor configured to capture an image of a reference chart and an image of a subject through an opening ; and an illumination light source that illuminates the subject. The light source is provided at a position outside the area of the subject and the reference chart, and a regular reflection area for regularly reflecting light incident on the two-dimensional image sensor from the illumination light source, a light source member for emitting illumination light, and a light source member. A light guide that guides the emitted illumination light, and the light guide includes an entrance that takes in the illumination light emitted from the light source member, and a reflected light of the irradiation light to the subject and the reference chart. The reflected light incident on the two-dimensional image sensor is disposed at a position outside the specular reflection area, and the illumination light emitted from the entrance is shielded between the exit for emitting the illumination light and the outside. Light guide to exit Comprising a part, and when seen from a direction perpendicular to the sensor surface of the two-dimensional image sensor, characterized in that it is an arrangement arranged in the order of the opening, the light guide of the emission port and the reference chart.

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

  Conventionally, a reference colorimetric means for measuring a reference color chart in advance so as to obtain a color reference value as RGB data, and an image of a subject including the reference color chart and a color measurement object are simultaneously or separately taken to obtain RGB data. 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 measurement object 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 colorimetric means is obtained, and at least the RGB data of the color measurement object is corrected using this difference. There has been proposed a colorimetric device including a calculation unit (see Patent Document 1). In this prior art, a reference color chart to be compared with a subject is placed near a subject to be measured, and the subject and the reference color chart are simultaneously imaged by a color video camera as a color image input unit. Discloses that after correcting RGB data of a subject using RGB data of a reference color chart obtained by imaging, the RGB data of the subject is converted into a color specification value in a standard color space.

  However, with the technology described in Patent Document 1, it is difficult to keep the positional relationship between the subject, the reference color chip, and the color video camera constant, and the imaging conditions fluctuate with each imaging, and stable imaging can be performed. There is a possibility that there is no.

  The present invention has been made in view of the above, and an object of the present invention is to provide an imaging unit, a colorimetric device, an image forming apparatus, a colorimetric system, and a colorimetric 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 captures an image of a subject and a reference chart through an opening, and an illumination light source that illuminates the subject. A specular reflection area provided at a position outside the area of the reference chart for specularly reflecting light incident on the two-dimensional image sensor from the illumination light source; a light source member for emitting illumination light; and illumination light emitted from the light source member And a light guide that guides the light, the light guide is configured to receive the illumination light emitted from the light source member, and the reflected light of the light emitted to the subject and the reference chart to the two-dimensional image sensor. It is arranged at a position where the reflected light that is incident is outside the specular reflection area, and guides the illumination light incident from the entrance to the exit while shielding between the exit that emits the illumination light and the outside. Light guide section , When seen from a direction perpendicular to the sensor surface of the two-dimensional image sensor, characterized in that it is an arrangement arranged in the order of the opening, the entrance and the reference chart of the light guide.

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

1 is a schematic perspective view of an image forming apparatus according to an embodiment of the present invention. FIG. 3 is a plan view of a carriage portion. FIG. 2 is a layout diagram of a recording head. FIG. 3 is a plan view of the imaging unit. FIG. 5 is a cross-sectional view of the imaging unit in FIG. FIG. 6 is a cross-sectional view of the imaging unit of FIG. FIG. 5 is a cross-sectional view of the imaging unit of FIG. The top view of a reference chart. FIG. 2 is a block diagram of a main part of the image forming apparatus. FIG. 2 is a block diagram of an imaging unit and a colorimetric control unit. FIG. 9 is an explanatory diagram of a process of acquiring a reference colorimetric value and an imaging reference RGB value from a reference sheet, and a process of acquiring a reference value linear conversion matrix. The figure which shows an example of the image data which imaged the reference chart and the imaging target simultaneously. The figure which shows an example of an initial reference RGB value. FIG. 4 is an explanatory diagram of a color measurement process. Explanatory drawing of reference RGB linear conversion matrix generation processing. The figure which shows the relationship between the initial reference RGB value and the reference RGB value at the time of color measurement. FIG. 4 is an explanatory diagram of a basic colorimetric process. FIG. 18 is a view showing a basic colorimetric process continued from FIG. 17. FIG. 3 is a plan view of an imaging unit including a light blocking member. FIG. 20 is a cross-sectional view of the imaging unit in FIG. FIG. 21 is a cross-sectional view of the imaging unit of FIG. FIG. 9 is a plan view of another imaging unit including a light blocking member. FIG. 23 is a cross-sectional view of the imaging unit of FIG. FIG. 24 is a cross-sectional view of the imaging unit in FIG. FIG. 24 is a cross-sectional view of the imaging unit of FIG. FIG. 24 is a cross-sectional view of the imaging unit of FIG. 23 taken along the line AA showing a light irradiation state that does not include specularly reflected light to the opening. The back view of another light shielding member. FIG. 1 is a system configuration diagram of an image forming system. FIG. 5 is a plan view of an imaging unit according to a second embodiment. FIG. 30 is a cross-sectional view of the imaging unit of FIG. FIG. 30 is a perspective view of a substrate and a light guide of the imaging unit in FIG. 29. The perspective view which shows the other example of arrangement | positioning structure of a light guide. FIG. 9 is a perspective view showing still another example of the arrangement configuration of the light guide. FIG. 4 is a front sectional view of an imaging unit without an optical path length changing member.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Although the following embodiments are preferred embodiments of the present invention, various technically preferable limitations are added thereto, but the scope of the present invention is unduly limited by the following description. However, not all components described in the present embodiment are essential components of the present invention.

  In addition, “Lab (Lab value)” described below means, for example, (value of) CIELAB (CIE 1976 L * a * b *) color space. Hereinafter, “L * a * b *” is simply referred to as “Lab” for convenience of explanation.

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

  In FIG. 1, in an image forming apparatus 1, a main body housing 2 is provided on a main body frame 3. A main guide rod 4 and a sub guide rod 5 extend in the main scanning direction indicated by a double arrow A in FIG. The main guide rod 4 movably supports the carriage 6. 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-shaped timing belt 7 is provided along the main guide rod 4. The timing belt 7 is stretched between a driving pulley 8 and a driven pulley 9. The drive pulley 8 is driven to rotate by a main scanning motor 10. The driven pulley 9 is provided in a state where a predetermined tension is applied to the timing belt 7. The drive pulley 8 is rotationally driven by the main scanning motor 10 to rotate the timing belt 7 in the main scanning direction according to the rotation direction.

  The carriage 6 is connected to the timing belt 7, and reciprocates in the main scanning direction along the main guide rod 4 by rotating the timing belt 7 in the main scanning direction by the driving pulley 8.

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

  As described later, the image forming apparatus 1 moves the carriage 6 in the main scanning direction while moving the carriage 6 on the platen 14 (see FIG. 2) in the sub-scanning direction (the direction of arrow B in FIG. 1) orthogonal to the main scanning direction. An image is recorded and output on the recording medium P by discharging ink onto the recording medium P conveyed intermittently.

  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 row 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, in order 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 so as to open and close the transport portion of the recording medium P. By opening the cover 13 at the time of maintenance of the image forming apparatus 1 or at the time of occurrence of a jam, maintenance work inside the main body housing 2 and work such as removal of the jam recording medium P can be performed.

  As shown in FIG. 2, the carriage 6 has recording heads 20y, 20m, 20c, and 20k mounted thereon. Each of the recording heads 20y, 20m, 20c, and 20k is connected to a cartridge of a corresponding color of the cartridge unit 11 by a pipe, and discharges the ink of the corresponding color onto the recording medium P facing the same. That is, the recording head 20y uses yellow (Y) ink, the recording head 20m uses magenta (M) ink, the recording head 20c uses cyan (C) ink, the recording head 20k uses black (K) ink, Each discharges.

  The recording head 20 is mounted on the carriage 6 such that the ejection surface (nozzle surface) faces downward (toward the recording medium P) in FIG. 1, and ejects ink to 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, at least over a moving 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 result of reading the encoder sheet 15 by the encoder sensor 21.

  As shown in FIG. 3, the recording head 20 mounted on the carriage 6 includes a plurality of nozzle rows each of the recording heads 20y, 20m, 20c, and 20k. An image is formed on the recording medium P by discharging ink from the nozzle row onto the recording medium P conveyed on the platen 14. In order to secure a wide image width that can be formed on the recording medium P by one scan of the carriage 6, the image forming apparatus 1 mounts the upstream recording head 20 and the downstream recording head 20 on the carriage 6. ing. Further, in order to improve the printing speed of black, the recording heads 20k, which are twice as many as the recording heads 20y, 20m and 20c for discharging color ink, are mounted on the carriage 6. Further, the recording heads 20y and 20m are divided in the main scanning direction and arranged adjacent to each other so that the colors are not changed between the forward path and the backward path by adjusting the order of the colors in the reciprocating operation of the carriage 6. Have 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.

  An imaging unit (imaging device) 30 is attached to the carriage 6, as shown in FIG. The imaging unit 30 captures an image of a subject in order to measure the color of the subject (color measurement object) during a color adjustment process described later.

  4 is a plan view, FIG. 5 is a sectional view taken along the line AA in FIG. 4, FIG. 6 is a sectional view taken along the line BB in FIG. 5, and FIG. As shown in FIG. 7 which is a cross-sectional view, a rectangular box-shaped frame 32 whose surface on the substrate 31 side 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 square 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, or an elliptical box shape. .

  The imaging unit 30 has an image sensor unit 34 disposed on the surface of the substrate 31 on the side of the frame 32 and at the center thereof. The image sensor unit (sensor unit) 34 includes a two-dimensional image sensor 35 such as a charge coupled device (CCD) sensor or a complementary metal oxide semiconductor (CMOS) sensor and a lens 36.

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

  The gap d is preferably smaller in consideration of the focal length for the two-dimensional image sensor 35, as described later. From the relationship with the flatness of the recording medium P, the size is set to a size such that the lower surface of the frame 32 does not contact the recording medium P, for example, about 1 mm to 2 mm.

  The opening 32c is provided with a reference color patch KP (see FIG. 10) and a colorimetric adjustment sheet CS of a reference sheet KS (see FIG. 10), which is an imaging target (subject) formed on the recording medium P, as described later. It is used to image the colorimetric adjustment color patch CP (see FIG. 5) (see FIG. 5). The opening 32c only needs to be large enough to capture at least all the images to be captured. Since there is a gap d between the frame 32 and the imaging target, the opening is formed slightly larger than the size of the imaging region of the imaging target in consideration of the shadow generated around the opening 32c.

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

  The reference chart KC is used by the imaging unit 30 as a comparison target with the reference color patches KP of the reference sheet KS and the colorimetric values of the colorimetric adjustment color patches CP of the colorimetric adjustment sheet CS to be imaged in the color adjustment processing. The image is captured simultaneously with the reference color patch KP and the colorimetric adjustment color patch CP. In other words, the image pickup unit 30 transmits the reference color patch KP of the reference sheet KS outside the frame 32 and the colorimetric adjustment color patch CP of the colorimetric adjustment sheet CS through the opening 32c provided in the bottom surface 32a of the frame 32. Simultaneously with the image pickup, a color patch on the reference chart KC attached to the concave portion 32d formed around the opening 32b of the bottom surface 32a of the frame 32 is picked up as a comparison target. In the imaging unit 30, the two-dimensional image sensor 35 sequentially scans pixels to read an image. Therefore, strictly, the reference color patch KP of the reference sheet KS, the colorimetric adjustment color patch CP of the colorimetric adjustment sheet CS, and the reference chart KC are not read at the same time, but the reference color patch KP and the colorimetric Since the images of the adjustment color patch CP and the reference chart KC can be acquired, they are expressed as simultaneous acquisition.

  As shown in FIG. 8, the reference chart KC includes a plurality of reference color patch rows Pa to Pd for color measurement on a surface (upper surface) inside the frame 32, similar to a reference sheet KS described later. A diameter measurement pattern row Pe, a distance measurement line lk, and a chart position identification marker mk are formed.

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

  The distance measurement line lk is formed as a rectangular frame line 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 four corner positions of the distance measurement line lk, and are markers for specifying each patch position.

  The 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 thereof 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 of the patches constituting the reference color patch rows Pa to Pd for colorimetry is defined as a standard color space Lab using a spectroscope BS (see FIG. 11), similarly to a reference color patch KP of a reference chart KC described later. Colorimetric values (Lab values) in the color space are measured in advance. This colorimetric value is a reference value for measuring the colorimetric adjustment color patches CP of the colorimetric adjustment sheet CS described later.

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

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

  The reference chart KC is provided 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 portion 32a of the frame 32. Therefore, the image can be captured by the two-dimensional image sensor 35 of the image sensor unit 34 at the same focal length as the imaging target such as the recording medium P.

  Further, the reference chart KC is detachably set 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 32, and the recording medium P The side surface is detachably held by a holding plate 32e detachably attached to the recess 32d. For this reason, even if dust or the like that has entered the frame 32 adheres to the surface of the reference chart KC, the holding plate 32e and the reference chart KC can be removed, the reference chart KC can be cleanly cleaned, and then attached again. The measurement accuracy of the reference chart KC can be improved.

  4 to 7 again, the imaging unit 30 is located on the center line Lo in the sub-scanning direction passing through the center of the image sensor unit 34 and in the sub-scanning direction from the center of the image sensor unit 34, respectively. A pair of illumination light sources 37 are provided on the substrate 31 at positions separated by a fixed amount at equal intervals. 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, right above the bottom surface 32aa for regular reflection absorption. As shown in FIG. 6, the bottom surface portion 32aa for regular reflection absorption is formed to have a width wider than the regular reflection region SA of the illumination light source 37.

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

  The image forming apparatus 1 according to the present embodiment has a block configuration 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-scanning driver 108, and the like, and the recording head 20, the encoder sensor 21, 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 for the image forming apparatus 1 and necessary system data. The CPU 101 controls each part of the image forming apparatus 1 based on a program in the ROM 102 while using the RAM 103 as a work memory, and executes basic processing as the image forming apparatus 1. 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 image capturing unit 30.

  In controlling 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 the driving of a paper transport unit 107 such as a sub-scanning motor and a transport roller (not shown) via a sub-scanning driver 108. Further, the CPU 101 controls the ink ejection timing and the ink ejection amount of 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 colorimetric control unit 106.

  As described above, the imaging unit 30 generates a colorimetric 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 below. The colorimetric adjustment color patch CP formed by the recording head 20 on the recording medium P during colorimetry is imaged, 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 image capturing unit 30, but the colorimetric control unit 106 may be configured integrally with the image capturing 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, but 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 the processed data to the colorimetric control unit 106.

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

  The shading correction unit 113 corrects an error in image data due to uneven illuminance of illumination light from the illumination light source 37 with respect to the imaging range of the image sensor unit 34 for the RGB image data input from the A / D conversion unit 112. And outputs the result 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 white balance 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 image data to the image format conversion unit 116.

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

  The interface unit 111 allows the imaging unit 30 to acquire various setting signals, timing signals, and light source driving signals transmitted from the colorimetric control unit 106, and to transmit image data from the image capturing unit 30 to the colorimetric control unit 106. Interface.

  The colorimetry 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 colorimetry value calculation unit 126. I have.

  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 arithmetic unit 124.

  As shown in FIG. 11, a non-volatile memory 125 stores Lab values, which are colorimetric values of colorimetric results of a plurality of reference color patches KP arranged and formed on a reference sheet KS by a spectroscope (colorimetric device) BS. And at least one of the XYZ values (in FIG. 11, both the Lab value and the XYZ value) are stored in the memory table Tb1 of the non-volatile memory 125 as reference colorimetric values 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 an 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 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 numbers, that is, in association with the reference colorimetric values. Further, the imaging unit 30 acquires an RGB value by capturing an image of each patch of the reference chart KC, and sets the RGB values of each patch of the reference chart KC as an initial reference RGB value RdGdBd under the control of the arithmetic unit 124. Is stored in the memory table Tb1 of the sex memory 125.

  When the reference colorimetric value, the imaging reference RGB value, and the initial reference RGB value RdGdBd are stored in the non-volatile memory 125, the colorimetric value calculation unit 126 calculates the XYZ values of the reference colorimetric values stored in the non-volatile memory 125. Then, a reference value linear conversion matrix for mutually converting is calculated with respect to a pair of the imaging reference RGB value, that is, a pair of the XYZ value and the imaging reference RGB value of 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-described processing in an initial state, and registers a reference colorimetric value, an imaging reference RGB value, and an initial reference RGB value RdGdBd, which are execution results, in the memory table Tb1 of the non-volatile memory 125. A value linear transformation matrix is calculated and stored in the nonvolatile memory 125.

  Further, as described later, the image forming apparatus 1 according to the present embodiment includes a colorimetric adjustment color patch CP as a subject formed on the recording medium P by the recording head 20 that changes with time during the color adjustment processing. The image sensor unit 34 simultaneously captures an image of the reference chart KC disposed inside the body 32 and outputs image data including the colorimetric adjustment color patches CP and the reference chart KC to the colorimetric control unit 106. The color measurement control unit 106 uses the color measurement adjustment color patches CP captured by the image sensor unit 34 during the color adjustment processing acquired from the imaging unit 30 as reference color patches (hereinafter, referred to as initial reference color patches) of the reference sheet KS. After being read by the imaging unit 30, after being 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 patches CP are compared with the initial reference RGB values 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 value that is the processing result of the colorimetric processing to the CPU 101. I 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 image data on which the color adjustment processing has been performed, thereby forming an image with improved color reproducibility.

  The image forming apparatus 1 of the present embodiment includes a ROM, an electrically erasable and programmable read only memory (EEPROM), an EPROM, a flash memory, a flexible disk, a compact disc read only memory (CD-ROM), and a compact disc rewritable (CD-RW). , A DVD (Digital Versatile Disk), an SD (Secure Digital) card, a MO (Magneto-Optical Disc) and other computer-readable recording media recorded on a computer-readable recording medium to execute the colorimetric method of the present embodiment. The image forming apparatus 1 is constructed as an image forming apparatus 1 having a colorimetric device that executes a colorimetric method for reading and introducing the color reproducibility described later at low cost and in a stable manner by reading and introducing the readout into the ROM 102 or the nonvolatile memory 125 or the like. . This colorimetry program is a computer-executable program described 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 the present embodiment will be described. The image forming apparatus 1 according to the present embodiment executes a colorimetric method for stably realizing color reproducibility at low cost.

  As shown in FIG. 11, the image forming apparatus 1 according to the present embodiment uses the spectroscope BS to measure the colorimetric results of a plurality of reference color patches arrayed and formed on the reference sheet KS among Lab values and XYZ values. Are stored as reference colorimetric values in the memory table Tb1 of the nonvolatile memory 125 corresponding to the patch numbers.

  Further, when the image forming apparatus 1 is in the state where the reference colorimetric values are stored in the memory table Tb1 in the non-volatile memory 125 and the image forming apparatus 1 is in the initial state due to manufacturing or overfall or the like, The reference sheet KS is set on the platen 14 of the image forming apparatus 1 and the movement of the carriage 6 is controlled to read the same reference patches as those read by the spectroscope BS of the reference sheet KS by the imaging unit 30. At the same time, as shown in FIG. 12, the image forming apparatus 1 captures each patch (initial reference color patch) of the reference chart KC disposed inside the frame 32.

  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 image processing unit 110 processes the image data of the image of the reference patch of the reference sheet KS as an RGB value which is an RGB value. As shown in FIG. 11, the arithmetic unit 124 stores the value, that is, the device-dependent signal depending on the device, in the memory table Tb1 of the nonvolatile memory 125 in correspondence with the patch number, that is, as the reference colorimetric value. Store it in correspondence. Further, the calculation unit 124 reads the initial reference color patches of the reference chart KC and processes the initial reference RGB values RdGdBd, which are the RGB values processed by the image processing unit 110, as shown in FIG. To be stored.

  The arithmetic unit 124 calculates the average value for each predetermined area, for example, the area (color measurement target area) indicated by the broken line in FIG. 12 in the image data of the initial reference color batch of the reference chart KC read by the imaging unit 30. It is calculated and set as an initial reference RGB value RdGdBd. By calculating the initial reference RGB values RdGdBd by averaging a large number of pixels in the color measurement target area in this manner, it is possible to reduce the influence of noise and improve the bit resolution. FIG. 13B is a scatter diagram in which initial reference RGB values RdGdBd are plotted, and FIG. 13A is a graph in which the initial reference RGB values RdGdBd are converted into reference Lab values Ldadbd and XYZ values converted into Lab values. This shows a state in which the reference XYZ value xdydzd is also 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 non-volatile memory 125, the colorimetric value calculation unit 126 calculates the XYZ values of the reference colorimetric values stored in the non-volatile memory 125. Then, a reference value linear conversion matrix for mutually converting is calculated with respect to a pair of the imaging reference RGB value, that is, a pair of the XYZ value and the imaging reference RGB value of 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, conveyance control of the recording medium P by the paper conveyance unit 107, and drive control of the recording head 20 based on image data and print settings input from the outside. Then, while the recording medium P is intermittently conveyed, ink ejection from each of 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 ejected from the recording heads 20y, 20m, 20c, and 20k may change due to characteristics unique to the device, aging, and the like. If the ink ejection amount changes, an image is formed in 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 a color adjustment process of obtaining a colorimetric value and performing color adjustment based on the colorimetric value at a predetermined color adjustment processing timing.

  That is, at the timing of the color adjustment processing, 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. It is recorded and output as a sheet CS. In the colorimetric adjustment sheet CS, a plurality of colorimetric adjustment color patches CP, which are color patches for colorimetric adjustment, are formed and output by the recording head 20. On the colorimetric adjustment sheet CS, a colorimetric adjustment color patch CP reflecting the output characteristics of the image forming apparatus 1 at the color adjustment processing timing, in particular, the output characteristics of the recording head 20 is formed. Note that the color patch data of the colorimetric adjustment color patch CP is stored in the nonvolatile memory 125 or the like in advance.

  Then, as described later, the image forming apparatus 1 uses the RGB values obtained by imaging the plurality of colorimetric adjustment color patches CP of the colorimetric adjustment sheet CS as the colorimetric RGB values (RGB values for colorimetry). The color target 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 colorimetric value obtained by converting the initial reference RGB value RdGdBd is used. A reference colorimetric value close to the distance (neighboring reference colorimetric value) is selected. The image forming apparatus 1 obtains a colorimetric value for converting the colorimetric target RGB value into the selected neighborhood reference colorimetric value, and records based on the image data after the 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 does not discharge the platen 14 in a state where the colorimetric adjustment sheet CS is set on the platen 14 or when the colorimetric adjustment sheet CS is recorded. While being held above, a plurality of colorimetric adjustment color patches CP on the colorimetric adjustment sheet CS on the platen 14 are imaged by the imaging unit 30 by controlling the movement of the carriage 6, and at the same time, the reference is made by the imaging unit 30. The patch of the chart KC is imaged. When the colorimetric adjustment color patches CP of the colorimetric adjustment sheet CS and the patches of the reference chart KC are simultaneously imaged by the imaging unit 30, the image processing unit 110 causes the image data of the colorimetric adjustment color patches CP of the colorimetric adjustment sheet CS to be imaged. After performing necessary image processing on the image data of the patches of the reference chart KC and the image data (RGB values) of the colorimetric adjustment color patches CP on the colorimetric adjustment sheet CS, the colorimetric target RGB values, that is, The image data (RGB values) of the patch of the reference chart KC is transmitted to the colorimetric control unit 106 as a device-dependent signal that depends on the device, as a reference RGB value RdsGdsBds at the time of colorimetry. As shown in FIG. 14, the colorimetric control unit 106 temporarily stores the data in the frame memory 121 (step S11).

  The colorimetric control unit 106 allows the colorimetric value calculating unit 126 of the arithmetic unit 124 to initialize the colorimetric RGB values stored in the frame memory 121 using a reference RGB linear conversion matrix described later. It is converted into RGB values RsGsBs (steps S12, S13).

  The calculation unit 124 of the colorimetric control unit 106 uses the converted initialized colorimetric RGB values RsGsBs as the colorimetric RGB values (step S14), executes a basic colorimetric process described later, and converts the Lab colorimetric values. Acquire (Step S15).

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

  That is, as shown in FIG. 15, the colorimetric value calculation unit 126 of the calculation unit 124 captures the reference color patch KP of the reference sheet KS by the imaging unit 30 at the same time as the image of the reference chart KC and simultaneously captures the patch of the reference chart KC. At the same time when the initial reference RGB values RdGdBd stored in the nonvolatile memory 125 and the colorimetric adjustment color patches CP of the colorimetric adjustment sheet CS are imaged by the imaging unit 30 at the time of colorimetry, the patches of the reference chart KC are imaged at the same time. Then, the colorimetric reference RGB value RdsGdsBds stored in the nonvolatile memory 125 is read from the nonvolatile memory 125. The colorimetric value calculating unit 126 obtains a reference RGB linear conversion matrix for converting the colorimetric reference RGB values RdsGdsBds into an initial reference RGB value RdGdBd, and stores the obtained reference RGB linear conversion matrix in the nonvolatile memory 125.

  That is, in FIG. 16, the points indicated by white points in FIG. 16A are points obtained by plotting the initial reference RGB values RdGdBd in the rgb space, and the solid points indicate the reference RGB values RdsGdsBds at the time of the colorimetry by rgb. These are points plotted in space. As can be seen from FIG. 16A, the value of the colorimetric reference RGB value RdsGdsBds fluctuates from the value of the initial reference RGB value RdGdBd. The directions of these fluctuations in the rgb space are substantially the same as indicated by arrows in FIG. 16B, but the direction of the shift differs depending on the hue. As described above, even if the patches of the same reference chart KC are imaged, the RGB values fluctuate due to a temporal change of the illumination light source 37, a temporal change of the two-dimensional image sensor 35, and the like.

  As described above, in the state where the color variation is obtained when the patch of the same reference chart KC is captured, the colorimetric value is obtained by using the colorimetric target RGB value obtained when the colorimetric adjustment color patch CP of the colorimetric adjustment sheet CS is captured. , There is a possibility that an error occurs in the colorimetric value by the amount of the variation.

  Therefore, the image forming apparatus 1 of the present embodiment initializes the colorimetric reference RGB value RdsGdsBds by using an estimation method such as the least square method between the initial reference RGB value RdGdBd and the colorimetric reference RGB value RdsGdsBds. A reference RGB linear conversion matrix to be converted into a reference RGB value RdGdBd is obtained. Further, the image forming apparatus 1 uses the reference RGB linear conversion matrix to image the colorimetric adjustment color patches CP of the colorimetric adjustment sheet CS with the imaging unit 30 and stores the colorimetric adjustment patches CP 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 performs a basic colorimetric process, which will be described later, using the converted initialization colorimetric target RGB values RsGsBs as the colorimetric target RGB values, and acquires Lab colorimetric values.

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

  The imaging unit 30 captures the reference color patch KP of the reference sheet KS as the subject and the colorimetric adjustment color patch CP of the colorimetric adjustment sheet CS through the opening 32c formed in the bottom surface 32a. At the same time, a patch of the reference sheet KS arranged in the opening 32c of the bottom surface 32a of the frame 32 is imaged. Thereby, the reference color patch KP of the reference sheet KS and the colorimetric adjustment color patch CP of the colorimetric adjustment sheet CS can be always imaged in the same positional relationship with the patch of the reference sheet KS as a subject, and a stable state can be obtained. Can be imaged.

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

  Therefore, it is possible to prevent the image of the reference color patch KP, the colorimetric adjustment color patch CP, and the reference chart KC, which are captured by the image sensor unit 34, from including a defective image due to the specular reflection light of the illumination light source 37. Colorimetry.

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

  Further, in the imaging unit 30, the arrangement condition of the opening 32c of the imaging area and the reference chart KC is arranged substantially symmetrically with respect to the center line Lo connecting the center of the lens 36 and the illumination light source 37. Therefore, the imaging conditions of the two-dimensional image sensor 35 can be made line-symmetric and the same, and the accuracy of the color adjustment processing and the colorimetric 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 color measurement target RGB value RsGsBs as described above and sets the initial color measurement target RGB value as the color measurement target RGB value, as shown in FIG. 17 and FIG. The reference colorimetric value (neighboring reference colorimetric value) that is close to the colorimetric value converted into the colorimetric target RGB value and that is close in distance is selected from the reference colorimetric values registered in. The image forming apparatus 1 executes a basic colorimetric process for obtaining a colorimetric value for converting a colorimetric target RGB value into a selected neighborhood reference colorimetric value, and performs 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 colorimetric adjustment color patches CP on the colorimetric adjustment sheet CS, obtains the initial colorimetric target RGB values RsGsBs as described above, and obtains the colorimetric target RGB. When the value is stored in the non-volatile memory 125 (step S21), the value is converted to the first XYZ value using the reference value linear conversion matrix (step S22) (step S23) and stored in the non-volatile memory 125 (step S21). 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 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), the data is stored in the nonvolatile memory 125 (Step S26). For example, in FIG. 17, the colorimetric value calculation unit 126 converts the first XYZ values (20, 80, 10) into the first Lab values (75, -60, 8) that are the image colorimetric values.

  Next, the colorimetric value calculation unit 126 searches for a reference colorimetric value (Lab value) of a plurality of color patches in the memory table Tb1 stored in the non-volatile memory 125, as indicated by the Lab space in FIG. Then, from the reference colorimetric values (Lab values), a set of color patches (neighboring color patches) closer to the first Lab value in the Lab space is selected (step S27). For example, the diagram of the Lab space in FIG. 17 shows a diagram in which 60 color patches are selected and plotted on the Lab space. As a method of 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 the plurality of color patches is calculated, and the first Lab value as the first colorimetric value is calculated. A method of selecting a reference Lab value of a color patch whose distance is closer to the value (in FIG. 17, a hatched reference Lab 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 value paired with the first Lab value of the selected set, that is, the first Lab of the selected set. Then, a combination of an imaging reference RGB value (selected RGB value) and a 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 converting between the set of the imaging reference RGB and the reference XYZ of the selected combination (selected set) using the least square method, and obtains the selected selection. The RGB value linear conversion matrix is stored in the nonvolatile memory 125 (Step S29).

  The colorimetric value calculation unit 126 converts the RGB values of the colorimetric objects obtained by capturing the respective colorimetric adjustment color patches CP of the colorimetric adjustment sheet CS to be measured with the imaging unit 30 using the selected RGB value linear conversion matrix. A second XYZ value as a second colorimetric value is obtained (step S30). The colorimetric value calculation unit 126 converts the second XYZ value into a second Lab value using a known conversion formula (Step S31), and obtains the final colorimetric value (Step S32).

  The colorimetric value calculation unit 126 performs image adjustment based on the image data on which color conversion has been performed using the obtained colorimetric values, and drives the recording head 20 based on the image data on which the image adjustment has been performed to form an image.

  That is, the image forming apparatus 1 according to the present embodiment is configured to capture and acquire a plurality of colorimetric adjustment color patches CP of the colorimetric adjustment sheet CS reflecting the output characteristics of the recording head 20 at the color adjustment processing timing. Using the reference value linear conversion matrix, a first Lab value when the reference sheet KS is imaged in the initial state is determined from the RGB values of the colorimetry target. The image forming apparatus 1 selects, from among the reference Labs of the patches of a plurality of colors registered in the memory table Tb1, a set of patches with a reference Lab value that is closer to the first Lab value in the Lab space, The colorimetric RGB values corresponding to the selected reference Lab values are converted to Lab values using a selected RGB value linear conversion matrix, thereby obtaining Lab colorimetric values. Then, the colorimetric value calculation unit 126 adjusts the image based on the image data that has been subjected to color conversion using the obtained colorimetric value, and drives the recording head 20 based on the image data after the image adjustment to form the image. I do.

  As described above, in the image forming apparatus 1 according to the present embodiment, the imaging unit 30 is configured such that the image capturing unit 30 simultaneously captures the opening 32c for capturing the subject and the subject captured through the opening 32c on the facing surface facing the subject. A predetermined box-shaped frame 32 in which a reference chart KC that provides a predetermined color reference is provided in a predetermined direction, and a light reflected from a subject facing the opening 32c and a reference chart KC. An image sensor unit (sensor unit) 34 that receives reflected light and simultaneously captures an image of the subject and the reference chart KC, and enters the image sensor unit 34 out of reflected light of the irradiation light on the subject and the reference chart KC. An illumination light source 37 disposed at a position where the reflected light is outside the specular reflection area.

  Therefore, the specularly reflected light from the illumination light source 37 mounted in the frame 32 overlaps with the subject outside the frame 32 and the image of the reference chart KC in the frame 32 and enters the image sensor unit 34. Can be prevented, and the subject and the reference chart KC can be always imaged in a stable positional relationship.

  In the imaging unit 30, the illumination light source 37 is disposed at a position where the regular reflection area overlaps the bottom surface 32aa, which is an intermediate area between the imaging area of the subject through the opening 32c and the imaging area of the reference chart KC. Have been.

  Therefore, with a simple and inexpensive configuration, it is assumed that the specularly reflected light from the illumination light source 37 overlaps the image of 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. Thus, the subject and the reference chart KC can be imaged at low cost and always in a stable positional relationship.

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

  Accordingly, it is possible to prevent the specular reflection light of the illumination light source 37 from being superimposed on the image of the subject outside the frame 32 and the image of the reference chart KC in the frame 32 and being incident on the image sensor unit 34. 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 sets the pair of illumination light sources 37 to the reference color patch KP of the reference sheet KS as a subject passing through the opening 32c, the colorimetric adjustment color patch CP of the colorimetric adjustment sheet CS, and By arranging the reference chart KC so as to deviate from the regular reflection area SA of the illumination light source 37, the effect of the regular reflection of the illumination light source 37 on the image captured by the image sensor unit 34 is prevented. The configuration for preventing the influence of the regular reflection of the illumination light source 37 is not limited to the above configuration. For example, a light blocking member 51 that blocks specularly reflected 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 cross-sectional view of the imaging unit 50 in FIG. 19 taken along arrow AA, and FIG. 21 is a cross-sectional view 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 will be omitted.

  That is, the light-shielding member 51 extends to the center line Lo in the sub-scanning direction passing through the center of the image sensor unit 34 just below the image sensor unit 34 and at a substantially intermediate position between the image sensor unit 34 and the bottom surface 32a. In the present state, it is disposed over the opposing side surfaces of the frame 32 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 to shield the regular reflection light emitted from the illumination light source 37a toward the bottom surface 32a and reflected by the bottom surface 32a from entering the image sensor unit 34. In addition, it has a width that does not prevent the reflected light from the reference chart KC and the reflected light from the subject through the opening 32 c from being incident on the image sensor unit 34.

  In the imaging unit 50, an optical path length changing member 52 is disposed in an 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 transmitting 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 32c, and is arranged in the frame 32. The fixing position of the optical path length changing member 52 is not limited to the position of the opening 32c inside the frame 32. In the optical path between the opening 32c and the two-dimensional image sensor 35, for example, a position on the imaging surface side of the frame 32, a 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 has an optical path length extending in accordance with the refractive index n of the optical path length changing member 52, and the two-dimensional image sensor 35 in a state where the image is raised. The floating amount C 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)
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 given by the following equation (2). You can ask.

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 is obtained. The optical path length can be lengthened by about 1/3 of Lp. If Lp = 9 [mm], L = Lc + 3 [mm], so that the image forming position of the reference chart KC and the focal position of the imaging surface of the recording medium P can be made coincident. The imaging surface of the recording medium P can be set in a conjugate relationship.

  The illumination light for irradiating the reference chart KC and the illumination light for irradiating the imaging surface of the recording medium P through the optical path length changing member 52 and the opening 32c are illumination lights from the same illumination light source 37a. Therefore, the imaging unit 50 can simultaneously image the reference chart KC and the imaging surface of the recording medium P under the same illumination conditions, as in the case of the imaging unit 30 described above. The illumination light source 37a 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 immediately below the lens 36. Therefore, the reference chart KC and the imaging area of the recording medium P can be uniformly illuminated under substantially the same conditions.

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

  As described above, the imaging unit 50 emits irradiation light in the direction in which the illumination light source 37a is vertically away from the image sensor unit 34 by a predetermined distance toward the bottom surface 32a, which is the opposite surface, and in the direction of the bottom surface 32a. The light shielding member 51 is disposed in such a state 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 specular reflection light of the illumination light source 37a from being incident on the image sensor unit 34, and it is possible to always image the subject and the reference chart KC in a stable positional relationship with high accuracy.

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

  Therefore, it is possible to reliably prevent the specular reflection light of the illumination light source 37a from being incident on the image sensor unit 34 with a simple configuration, and to always accurately and inexpensively position the subject and the reference chart KC in a stable positional relationship. Images can be taken.

  In this case, when the focal length of the subject such as the reference chart KC and the recording medium P to the image sensor unit 34 is negligible in accuracy, the imaging unit 50 changes the optical path length as shown in FIGS. The member 52 need 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 is a reflection light (specular reflection light) of the regular reflection area SA of the light emitted from the illumination light source 37a to the bottom surface 32a. Has a necessary and sufficient width to be incident on the image sensor unit 34.

  In this case, the influence of the specularly reflected light on the captured image can be more reliably and inexpensively prevented.

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

  The light blocking member 53 may be formed integrally with the frame 32 or may be attached to the frame 32 by a method such as adhesion or fixing.

  Further, in the above description, the colorimetric processing is performed by the colorimetric control unit 106 of the image forming apparatus 1, but the colorimetric processing need not be performed inside the image forming apparatus 1. For example, as shown in FIG. 28, as an image forming system (colorimetric system) 200, an image forming apparatus 210 is connected to an external device 220, and image data captured by the image forming device 210 is transferred to the external device 220. The external device 220 performs a color adjustment process involving a colorimetric process, outputs image data after color adjustment to the image forming device 210, and the image forming device 210 outputs the image data from the external device 220. May be formed based on the image.

  That is, the image forming apparatus 210 includes an engine 211, an operation display unit 212, an I / F unit 213, another I / F unit 214, and the like, and each unit is connected by a bus 215. Further, as the external device 220, for example, a computer having a normal hardware configuration and a software configuration can be used, and a color adjustment program including a color measurement program for executing a color adjustment process involving the color measurement process of the present invention as software , A color adjustment process involving a colorimetric process is executed. 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 an external device 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, or the like, and is a wired line. Or wireless.

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

  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 colorimetric adjustment color patches CP on a recording medium based on the color patch data of the colorimetric adjustment color patches CP sent from the external apparatus 220 under the control of the CPU 221 of the external apparatus 220. To generate a colorimetric adjustment sheet CS. The image forming apparatus 210 reads the generated colorimetric adjustment color patch CP of the colorimetric adjustment sheet CS by the imaging unit and transmits the colorimetric adjustment color patch CP to the external device 220 via the I / F unit 213.

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

  The hard disk 229 stores the program and various data necessary for executing the color adjustment processing, in particular, the colorimetry of a plurality of reference color patches KP arranged and formed on the reference sheet KS described in the above embodiment. At least one of the resulting Lab value and XYZ value, the imaging reference RGB value when the imaging unit of the image forming apparatus 210 reads the reference color patch KP of the reference sheet KS, the reference value linear conversion matrix, The table and the selected RGB value linear conversion matrix, the initial reference RGB value RdGdBd of each color patch of the reference chart KC read at the same time as the reference sheet KS, and the reference read simultaneously when the colorimetric adjustment color patches CP of the colorimetric adjustment sheet CS are read Reference RGB value RdsGdsBds for color measurement of reference patch of chart KC and 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 device such as a scanner device, a multifunction device, or another external device via a line such as a network, and receives image data to be output to the image forming device 210 as an image.

  The image processing unit 223 performs various image processing necessary for forming and outputting the image data by 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 executes the colorimetric processing performed by the arithmetic unit 124 of the colorimetric control unit 106, in particular, the colorimetric value calculation unit 126 to execute the colorimetric value processing. Is calculated, image data is subjected to color adjustment based on the colorimetric values, and output to the image forming apparatus 210.

  In the image forming system 200 shown in FIG. 28, the operation of the image forming apparatus 210 is controlled by the external device 220. However, the image forming apparatus 210 itself includes a controller such as a CPU, and the image forming operation itself is not controlled. The external device 220 may control the controller to execute only the colorimetric processing for obtaining the colorimetric value or only the color adjustment processing including the colorimetric processing.

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

  FIGS. 29 to 34 are diagrams showing a second embodiment of the image pickup unit, the colorimetric device, the image forming device, the colorimetric system, and the colorimetric method of the present invention. FIG. 29 is a plan view of an image pickup unit 300 mounted on an image forming apparatus to which the second embodiment of the image pickup unit, the colorimetric device, the image forming device, the colorimetric system and the colorimetric method according to the present invention is applied. FIG. 30 is a sectional view taken along the line AA of 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 image pickup unit 300 similar to the image pickup unit 30 shown in FIGS. Therefore, in the description of the present embodiment, the same components as those of the first embodiment are denoted by the same reference numerals, and the same reference numerals are used without showing the drawings, 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. The imaging unit 300 captures an image of the subject in order to measure the color of the subject (colorimetric object) during the color adjustment processing, similarly to the imaging unit 30 and the like of the first embodiment.

  In the imaging unit 300, an image sensor unit 34 is provided on the surface of the substrate 31 on the side of the frame 32 and at the center thereof. 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 as described above.

  The imaging unit 300 includes the frame 32 in a state where the lower surface of the bottom surface (opposing surface) 32a opposite to the substrate 31 faces the recording medium P on the platen 14 with a predetermined distance d. It is attached to the carriage 6. A substantially rectangular opening 32b and an opening 32c are formed in the bottom portion 32a in the main scanning direction with the center line Lo as a center, with the specular reflection absorbing bottom portion 32aa having a predetermined width interposed therebetween. I have. The bottom surface 32aa may be subjected to a predetermined surface treatment for absorbing specularly reflected light.

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

  The opening 32b has a recess 32d of a predetermined width formed on the surface on the recording medium P side along the periphery of the opening 32b, and the reference chart KC is detachably set in the recess 32d. A holding plate 32e is attached to the recess 32d of the opening 32b of the frame 32 so as to cover the surface of the reference chart KC on the recording medium P side and to be held in the recess 32d of the reference chart KC. The opening 32b is closed by the reference chart KC and the holding plate 32e. The surface of the holding plate 32e on the recording medium P side is a smooth flat surface. The reference chart KC is the same as above. Further, similarly to the image pickup unit 50 shown in FIGS. 19 to 21, the image pickup unit 300 closes the opening 32c and sets 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 provided therein.

  In the imaging unit 300, the light guide 301 is provided on the surface of the substrate 31 on the side of the frame 32. 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 located on the center line Lo in the sub-scanning direction passing through the center of the image sensor unit 34 and one entrance port 301 a located outside the frame 32, and each of the light guides 301 extends from the center of the image sensor unit 34. It has a pair of emission ports 301b that open toward the bottom surface 32a at positions separated by a predetermined amount in the scanning direction at equal intervals, and a light guide section 301c that connects the entrance port 301a and the emission port 301b. The light guide 301c is bifurcated from a position near the entrance 301a, and is connected to a pair of exits 301b, respectively. That is, the light exit 301b of the light guide 301 has the regular reflection area SA whose reference color patch KP of the reference sheet KS as a subject passing through the opening 32c, the colorimetry adjustment color patch CP of the colorimetry adjustment sheet CS, and The illumination light is emitted in a state where the illumination light is located on the bottom surface portion 32aa deviated from the reference chart KC.

  The light guide 301 is made of a member having a good light guide 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 with a light shielding member for preventing leakage of light to the outside and incidence of light 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 types of light sources (illumination light sources 37 and 302) are not limited to LEDs. For example, an organic EL or the like may be used as a light source. When an organic EL is used as a light source, illumination light close to the spectral distribution of sunlight is 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 port 301a so that the same amount of illumination light is emitted from the pair of exit ports 301b, as indicated by arrows in FIG. Attached to.

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

  The upper end surface of the frame 32 is formed with a concave portion 32f through which the light guide portion 301c of the light guide 301 can pass. The light guide 301 is provided with the light guide 301c passing between the recess 32f and the substrate 31. Even if a light blocking member (not shown) for preventing external light from entering into the frame 32 is provided between the concave portion 32f of the frame 32 through which the light guide portion 301c passes and the substrate 31. Good.

  29 to 31, the light guide 301 is drawn into the frame 32 from the outside of the frame 32 through the concave portion 32f formed on the side surface of the frame 32, and the frame It is attached to the surface on the body 32 side. The emission port 301b is disposed on the center line Lo and directly above the bottom surface 32aa between the opening 32b and the opening 32c in which the reference chart KC is provided. 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 located directly above the bottom surface 32aa between the opening 32b and the opening 32c where the reference chart KC is provided on the center line Lo, A pair of illumination windows 31a are formed on the substrate 31 symmetrically positioned with respect to the image sensor unit 34, and the light guide 301 in which the emission port 301b is located in the illumination window 31a is arranged so as to crawl on the upper surface of the substrate 31. May be. In this case, the light guide 301 is located on the upper surface of the substrate 31 opposite to the frame 32, and transmits incident light from the illumination light source 302 disposed in the entrance 301 a through the entrance 301 a. Then, the light is radiated into the frame 32 from the emission port 301b through the illumination window 31a of the substrate 31. At this time, the light guide 301 has an emission port 301b at a position where the light is emitted with the regular reflection area SA of the illumination light serving as the bottom surface portion 32aa.

  Further, 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 bifurcated light guide 301c. For example, as shown in FIG. 33, a light guide 303 formed linearly on the center line Lo may be used. In this case, the imaging unit 300 is located on the center line Lo, directly above the bottom surface 32aa between the opening 32b and the opening 32c provided with the reference chart KC, and A pair of illumination windows 31a are formed on the substrate 31 at positions symmetrical with respect to 34. In the illumination window 31a, a pair of exit ports 303b formed on the surface on the substrate 31 side are located at both end positions of the linear light guide 303, and the pair of exit ports 303b are arranged. Are connected by a light guide section 303c. The light guide 303 has an entrance port 303a formed on one end face in the longitudinal direction. An illumination light source 302 is disposed at a position facing the entrance 303a. The light guide 303 has a function of equally dividing the illumination light incident on the entrance 303a from the illumination light source 302 into a pair of exits 303b formed at both ends in the longitudinal direction and emitting the light from the exits 303b. Have. The light guide 303 illuminates the equally divided illumination light into the frame 32 through the illumination window 31 a formed in the substrate 31. The light guide 303 is provided with an emission port 303b at a position where the light is emitted in a state where the regular reflection area SA of the illumination light becomes the bottom surface portion 32aa.

  Further, in the above description, in the imaging unit 300, the optical path length changing member 52 is disposed in the frame 32 so as to cover the opening 32c, 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 capture the reference chart KC and the subject when performing the colorimetric processing at an appropriate timing, similarly to the imaging units 30 and 50 of the first embodiment. Can be

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

  As described above, in the image forming apparatus 1 of the present embodiment, in the image forming unit 300, as the illumination light source, one illumination light source (light source member) 302 that emits the illumination light and the illumination light emitted from the illumination light source 302 are used. A light guide 301 for guiding light; the light guide 301 captures illumination light emitted from the illumination light source 302; and an image of reflected light of light emitted to the subject and the reference chart KC. An output port 301b, which is disposed at a position where the reflected light incident on the sensor unit 34 is outside the regular reflection area SA and emits illumination light, is connected to the input port 301a and the output port 301b while shielding light from the outside. And a light guide section 301c for guiding illumination light incident from the entrance port 301a to the exit port 301b.

  Therefore, the imaging unit 300 can illuminate and image the reference chart KC and the subject under the same illumination conditions using the light guides 301 and 303 while preventing regular reflection, and with a simple configuration, the imaging unit 300 can be further improved. High-precision imaging and colorimetry can be performed with high accuracy.

  Further, the light guide 301 of the imaging unit 300 has one entrance port 301a disposed at a position where the illumination light emitted from the illumination light source 302 is taken in, and the exit port 301b is provided in the imaging area of the subject through the opening 32c. And a base area 32aa, which is an intermediate area having a predetermined length with respect to the imaging area of the reference chart KC, is arranged in a pair at a position where illumination light is emitted to a position symmetrical in the length direction with respect to the center in the length direction of the bottom surface 32aa. Then, the light guide portion 301c is connected to the entrance 301a and is separated in the middle to be connected to the pair of exits 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 the colorimetry 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 embodiment in the same manner as described above.

  As described above, the invention made by the inventor has been specifically described based on the preferred embodiment. However, the present invention is not limited to the above-described embodiment, and various modifications may be made without departing from the gist of the invention. It goes without saying that it is possible.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Main body housing 3 Main body frame 4 Main guide rod 5 Sub guide rod 6 Carriage 6a Connecting piece 7 Timing belt 8 Drive pulley 9 Follower 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 32a Bottom part 32b Opening 32c Opening 32d Depression 32e Holding plate 32f Depression 32aa Bottom part 33 Fastening member 34 Image sensor part 35 2D 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 scanning driver 105 Recording head driver 106 Colorimetric control unit 107 Paper transport unit 108 Sub-scanning driver 110 Image processing unit 111 Interface unit 112 A / D conversion unit 113 Shading correction unit 114 White balance correction unit 115 Gamma correction unit 116 Image format Conversion unit 121 Frame memory 122 Timing signal generation unit 123 Light source drive control unit 124 Operation unit 125 Non-volatile memory 126 Colorimetric value calculation unit 200 Image forming system 210 Image forming device 211 Engine 212 Operation display unit 213 I / F unit 214 Other I / F 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 Inlet 301b Outlet 301c Light guide 303 Light guide 303a Inlet 303b Outlet 303c Light guide Lo Center line KS Reference sheet KP Reference color patch CS measurement Color adjustment sheet CP Colorimetry adjustment color patch KC Reference chart Pa to Pd Reference color patch row Pe Dot diameter measurement pattern row lk Distance measurement line mk Chart position identification marker

JP-A-5-223624

Claims (6)

A two-dimensional image sensor that captures an image of a reference chart and captures an image of a subject through an opening;
An illumination light source for illuminating the subject,
The illumination light source is
A regular reflection area provided at a position outside the area of the subject and the reference chart, and regularly reflecting light incident on the two-dimensional image sensor from the illumination light source;
A light source member for emitting illumination light,
A light guide that guides illumination light emitted from the light source member,
The light guide,
An entrance for taking in illumination light emitted from the light source member,
Of the reflected light of the irradiation light on the subject and the reference chart, the reflected light incident on the two-dimensional image sensor is arranged at a position outside the regular reflection area, and an emission port for emitting the illumination light. ,
A light guide unit that guides the illumination light incident from the entrance to the exit while shielding light from the outside,
An imaging unit, wherein when viewed from a direction perpendicular to a sensor surface of the two-dimensional image sensor, the opening, the light exit of the light guide, and the reference chart are arranged in this order. The light guide is arranged at a position where the entrance port takes in light emitted from the illumination light source, and the exit port is located at a center in a longitudinal direction of the region having a predetermined length. On the other hand, a pair is arranged at a position where the illumination light is emitted to a position symmetrical in the length direction, and the light guide portion is connected to the entrance and separated in the middle and connected to the pair of exits. The imaging unit according to claim 1, wherein: Imaging means for simultaneously imaging a reference chart composed of a plurality of colors and an arbitrary subject; calculating means for calculating a colorimetric value of the subject based on the subject imaged by the imaging means and image data of the reference chart. A colorimeter comprising:
A colorimetric device comprising the image pickup unit according to claim 1 or 2 as the image pickup means. An image forming apparatus that forms an image using image data color-adjusted based on a colorimetric value measured by a colorimetric device,
An image forming apparatus comprising the colorimetric device according to claim 3 as the colorimetric device. Imaging means for simultaneously imaging a reference chart composed of a plurality of colors and an arbitrary subject; calculating means for calculating a colorimetric value of the subject based on the subject imaged by the imaging means and image data of the reference chart. A communication system that connects the imaging unit and the calculation unit,
A colorimetric system comprising the image pickup unit according to claim 1 or 2 as the image pickup means. A color measurement method executed by a color measurement device including the imaging unit according to claim 1 or 2 and a calculation unit,
A step in which the imaging unit simultaneously captures an image of an arbitrary subject with a reference chart including a plurality of colors;
A step of calculating a colorimetric value of the subject based on the subject imaged by the imaging unit and image data of the reference chart.