JP2014078769A - Imaging unit, colorimetry device, colorimetry system, and image forming device - Google Patents

Abstract

The present invention stably captures an image of a subject and a reference chart while preventing adhesion of dust and the like.
An imaging unit 30 of an image forming apparatus 1 is imaged on a bottom surface 32a facing a subject at the same time as an opening 32c for imaging the subject and a subject imaged through the opening 32c. From a box-shaped frame 32 provided side by side with a reference chart KC that provides a color reference, an illumination light source 37 that illuminates the subject and the reference chart KC under substantially the same illumination conditions, and a subject that faces the opening 32c. And an image sensor unit 34 that receives the reflected light from the reference chart KC and images the subject and the reference chart KC at the same time. Injected from 63 toward the subject.
[Selection] Figure 5

Description

  The present invention relates to an imaging unit, a color measurement device, a color measurement system, and an image forming apparatus, and more specifically, an imaging unit, a color measurement device, which stably captures an object and a reference chart while preventing dust and the like from being attached. The present invention relates to a color measurement system and an image forming apparatus.

  Image forming apparatuses such as color ink jet type image forming apparatuses and color electrophotographic image forming apparatuses are offset by advertising media and pamphlets that require a high image but a relatively small number of copies as the image quality improves. It is also used for printing.

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

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

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

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

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

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

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

Conventionally, a case, a reference pattern used for colorimetry arranged in the case, and a part of the image pickup region are picked up by the reference pattern, and a colorimetric object is picked up in another region. A two-dimensional sensor; an imaging element that is disposed on the optical path of the reference pattern and the colorimetric object and forms an image of the reference pattern on a sensor surface of the two-dimensional sensor; An imaging apparatus comprising: a transmissive member disposed in an optical path between the sensor and the color measurement object and having a refractive index for setting the imaging position of the color measurement object by the imaging element as the two-dimensional sensor surface Has been proposed (see Patent Document 1). In this prior art, the frame is moved on the color measurement target recorded on a sheet or the like, and the reference pattern and the color measurement target in the frame are imaged.

  However, in the prior art described in the above publication, since the frame of the imaging device is moved on the color measurement target recorded on the paper or the like, the reference pattern and the color measurement target in the frame are imaged. When floating dust adheres to the imaging target or imaging device, or when imaging is performed after the imaging target is recorded by the ink ejection method, not only floating dust but also ink mist adheres to the imaging device or imaging target, and the imaging quality is low. There was a problem of lowering.

  Therefore, an object of the present invention is to always capture an image of a subject and a reference chart in a stable positional relationship while preventing the influence of foreign matters such as dust from entering the imaging result.

  In order to achieve the above object, an imaging unit according to claim 1 is an imaging unit having sensor means for imaging a predetermined area including a subject, and is disposed in the area and positioned outside the imaging unit. And a reference chart that is imaged by the sensor means together with the subject and an air ejecting means that ejects air from the inside of the imaging unit toward the subject.

  According to the present invention, it is possible to always capture an image of a subject and a reference chart in a stable positional relationship while preventing the influence of foreign matters such as dust from entering the imaging result.

1 is a schematic perspective view of an image forming apparatus to which an embodiment of the present invention is applied. The top view of a carriage part. FIG. The top view of the imaging unit of a state which removed the upper cover. AA arrow sectional drawing of the imaging unit of FIG. BB arrow sectional drawing of the imaging unit of FIG. The top view of a reference | standard chart. FIG. 3 is a block diagram of a main part of the image forming apparatus. The block block diagram of an imaging unit and a colorimetry control part. Explanatory drawing of the acquisition process of the reference | standard colorimetry value and imaging reference RGB value from a reference | standard sheet, and a reference value linear transformation matrix acquisition process. The figure which shows an example of the image data which imaged the reference | standard chart and the imaging target simultaneously. The figure which shows an example of an initial reference RGB value. Explanatory drawing of a colorimetry process. Explanatory drawing of the linear conversion matrix production | generation process between reference | standard RGB. The figure which shows the relationship between an initial reference | standard RGB value and the reference | standard RGB value at the time of colorimetry. Explanatory drawing of a basic colorimetry process. FIG. 17 is a diagram showing basic colorimetry processing continued from FIG. 16. Front sectional drawing of the imaging unit which shows the other example of an air injection opening. AA arrow sectional drawing of the imaging unit of FIG. 1 is a system configuration diagram of an image forming system to which a color measurement system is applied.

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

  1 to 20 are diagrams illustrating an embodiment of an imaging unit, a colorimetric device, a colorimetric system, and an image forming apparatus according to the present invention, and FIG. 1 is a schematic perspective view of an image forming apparatus 1 to which an embodiment of a system and an image forming apparatus is applied.

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

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

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

  The image forming apparatus 1 houses a cartridge unit 11 and a maintenance mechanism unit 12 at both end positions in the main scanning direction in the main body housing 2, and the cartridge unit 11 includes yellow (Y), magenta (M), and cyan. (C) and the cartridge which each accommodates each ink of black (K) is accommodated so that replacement | exchange is possible. Each cartridge of the cartridge unit 11 is connected to recording heads 20y, 20m, 20c, and 20k (see FIG. 2) of the corresponding color of the recording head 20 mounted on the carriage 6 by pipes (not shown), and from the cartridges through the pipes. Ink is supplied to the recording heads 20y, 20m, 20c, and 20k. In the following description, the recording heads 20y, 20m, 20c, and 20k are collectively referred to as the recording head 20.

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

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

  The maintenance mechanism unit 11 performs cleaning of the ejection surface of the recording head 20, capping, ejection of unnecessary ink, and the like to discharge unnecessary ink from the recording head 20 and maintain the reliability of the recording head 20. Yes.

  The image forming apparatus 1 is provided with a cover 13 that can open and close the conveyance part of the recording medium P. When the image forming apparatus 1 is maintained or when a jam occurs, the cover 13 is opened so that the inside of the main body housing 2 can be opened. Maintenance work, removal of the jam recording medium P, and the like can be performed.

  As shown in FIG. 2, the carriage 6 is mounted with recording heads 20y, 20m, 20c, and 20k. The recording heads 20y, 20m, 20c, and 20k are piped to the cartridges of the corresponding colors of the cartridge unit 11, respectively. Are connected to each other, and inks of corresponding colors are ejected onto the opposing recording medium P. That is, the recording head 20y is yellow (Y) ink, the recording head 20m is magenta (M) ink, the recording head 20c is cyan (C) ink, and the recording head 20k is black (K) ink. Discharge each.

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

  In the image forming apparatus 1, an encoder sheet 15 is disposed in parallel with the timing belt 7, that is, the main guide rod 5, over at least the movement range of the carriage 6. The encoder 6 reads the encoder sheet 15 on the carriage 6. A sensor 21 is attached. The image forming apparatus 1 controls the movement of the carriage 6 in the main scanning direction by controlling the driving of the main scanning motor 10 based on the reading result of the encoder sheet 15 by the encoder sensor 21.

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

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

  The imaging unit 30 is a plan view in a state where the upper cover 31 is peeled off, FIG. 4 is a sectional view taken along the line AA in FIG. 4, and FIG. 6 is a sectional view taken along the line BB in FIG. As shown, a rectangular box-shaped frame 32 having an open surface on the upper cover 31 side is fixed to the upper cover 31 by a fastening member (not shown), and the upper cover 31 is shown in FIG. It is fixed to the carriage 6. The frame body 32 is not limited to a rectangular box shape, and may be, for example, a cylindrical box shape having a bottom surface portion 32a in which openings 32b and 32c are formed, an elliptical cylinder box shape, or the like. .

  As shown in FIGS. 4 and 5, the imaging unit 30 is a recess formed in the inner wall surface of the frame 32 at a position within the frame 32 and a predetermined amount away from the upper cover 31 toward the bottom surface 32 a. The sensor board 33 is attached in a state of being fitted into the frame body 32. The sensor board 33 is attached to the frame body 32 by fitting, screwing, and the inner side of the frame body 32 between the upper cover 31 and the sensor board 33. An appropriate method such as fixing by a fixing member inserted in a state along the wall surface can be used.

  The sensor substrate 33 is shorter than the length of the frame body 32 in the main scanning direction, which is the moving direction of the imaging unit 30, and there is a gap between the both ends of the main scanning direction and the inner wall surface of the frame body 32. It has become.

  The sensor substrate 33 is a surface on the bottom surface portion 32a side, and an image sensor unit 34 is disposed at the center in the main scanning direction and the sub-scanning direction, and a CCD (Charge Coupled Device) sensor or a CMOS (Complementary Metal). A two-dimensional image sensor 35 such as an Oxide Semiconductor) sensor and a lens unit 36 are provided.

  In the imaging unit 30, the frame 32 has a lower surface of a surface portion (hereinafter referred to as a bottom surface portion) 32 a opposite to the upper cover 31 facing the recording medium P on the platen 14 with a predetermined distance d. In this state, the bottom surface portion (opposing surface) 32a is formed with a substantially rectangular opening 32b and an opening 32c in the main scanning direction with the center line Lo as the center. Yes. As will be described later, the gap d is preferably smaller in consideration of the focal length with respect to the two-dimensional image sensor 35. However, due to the flatness of the recording medium P, the lower surface of the frame 32 and the recording medium P are separated from each other. The size which does not contact, for example, is set to about 1 mm to 2 mm.

  As will be described later, the opening 32c includes a reference color patch KP (see FIG. 10) of the reference sheet KS (see FIG. 10) that is an imaging target (subject) formed on the recording medium P, and a colorimetric adjustment sheet CS. The colorimetric adjustment color patch CP (see FIGS. 5 and 13) (see FIGS. 5 and 13) is used for imaging. The opening 32c may be at least large enough to capture all images of the imaging target (for example, one patch). However, since there is a gap d between the frame 32 and the imaging target, the opening 32c In consideration of the shadow that occurs in the periphery of the image, it is formed in an opening state that is slightly larger than the size of the imaging region to be imaged.

  In the opening 32b, a concave portion 32d having a predetermined width is 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 concave portion 32d. A holding plate 32e that covers the surface of the reference chart KC on the recording medium P side and is held by the reference chart KC is provided in the recess 32d of the opening 32b of the frame 32 in a detachable manner. 32b is closed by the reference chart KC and the holding plate 32e. The holding plate 32e has a smooth flat surface on the recording medium P side.

  The reference chart KC is compared with the reference color patch KP of the reference sheet KS and the imaged colorimetric value of the colorimetric adjustment color patch CP of the colorimetric adjustment sheet CS that is the image pickup object in the color adjustment process. Photographed at the same time as the reference color patch KP and the colorimetric adjustment color patch CP. That is, the imaging unit 30 includes the reference color patch KP of the reference sheet KS and the colorimetric adjustment color patch of the colorimetry adjustment sheet CS that are located outside the frame 32 through the opening 32c provided in the bottom surface part 32a of the frame 32. Simultaneously with the imaging of the CP, the color patch on the reference chart KC attached to the recess 32d formed around the opening 32b of the bottom surface portion 32a of the frame 32 is imaged as a comparison target.

  Note that since the image pickup unit 30 reads the image by the two-dimensional image sensor 35 sequentially scanning the pixels, strictly speaking, the reference color patch KP of the reference sheet KS and the color measurement adjustment color patch CP of the color measurement adjustment sheet CS Although the reference chart KC is not read at the same time, the images of the reference color patch KP, the colorimetric adjustment color patch CP, and the reference chart KC can be acquired within one frame.

  As shown in FIG. 7, the reference chart KC has a plurality of reference color patch rows Pa to Pd and dots for color measurement on the inner surface (upper surface) of the frame 32, as shown in FIG. A diameter measurement pattern row Pe, a distance measurement line lk, and a chart position specifying marker mk are formed.

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

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

  A colorimetric control unit 106 (see FIGS. 8 and 9) described later identifies the distance measurement line lk and the chart position specifying markers mk at the four corners from the image data of the reference chart KC acquired from the imaging unit 30. The position of the reference chart KC and the position of each pattern are specified.

  Each patch constituting the reference color patch rows Pa to Pd for colorimetry is a Lab color that is a standard color space using a spectroscope BS (see FIG. 10), similarly to a reference patch KP of a reference chart KC described later. A colorimetric value (Lab value) in the space is measured in advance, and becomes a reference value when measuring a colorimetric adjustment color patch CP of a colorimetric adjustment sheet CS described later.

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

  The reference chart KC is disposed in the recess 32d formed on the outer periphery of the surface on the recording medium P side of the opening 32b formed in the bottom surface portion 32a of the frame 32. Images can be taken by the two-dimensional image sensor 35 of the image sensor unit 34 at the same focal length as that of the imaging target.

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

  4 to 6 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 from the center of the image sensor unit 34, as shown in FIG. A pair of illumination light sources 37 are disposed on the sensor substrates 33 that are spaced apart from each other by a predetermined amount in the sub-scanning direction. As the illumination light sources 37, LEDs (Light Emitting Diodes) or the like are used. Yes.

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

  The lens unit 36 is disposed in the optical path of the reflected light from the subject and the reference chart KC to the two-dimensional image sensor 35, and condenses the reflected light on the two-dimensional image sensor 35. As shown in FIG. 5, in the lens unit 36, one imaging lens is used as the lens 36a, but a plurality of lenses may be used. The lens 36 a of the lens unit 36 is moved in a direction perpendicular to the two-dimensional image sensor 35 by the lens position adjustment mechanism 40 and a direction away from the two-dimensional image sensor 35.

  The lens position adjusting mechanism 40 includes drive motors 41a and 41b disposed in the main scanning direction with the lens 36a interposed therebetween, guide rails 42a and 42b and guide rails 42a and 42b that are rotationally driven by the drive motors 41a and 41b. A lens holder 43 or the like that is stretched between and holds the lens 36a is provided. The drive motors 41a and 41b are rotationally controlled by a lens position adjusting unit 50 (see FIG. 9).

  The guide rails 42a and 42b extend in the vertical direction with respect to the two-dimensional image sensor 35 and are rotationally driven by the respective drive motors 41a and 41b. The outer circumferential surfaces of the guide rails 42a and 42b are axially spiral thread grooves or screw threads. The part is formed.

  Although not shown, the lens holder 43 is formed with screw holes into which the guide rails 42a and 42b are inserted at both ends, and a screw thread of the screw holes or a screw part of the screw groove is a screw part of the guide rails 42a and 42b. And move toward or away from the two-dimensional image sensor 35 according to the rotation direction of the guide rails 42a and 42b.

  The drive motors 41a and 41b are rotationally driven in the same direction by a motor drive signal from a lens position adjusting unit 50 described later. As will be described later, when the drive motors 41a and 41b are pulse motors, the lens position adjustment unit 50 controls the amount of movement of the lens 36a by controlling the number of pulses of the motor drive signal output to the drive motors 41a and 41b. By changing the sign of the motor drive signal output from the lens position adjustment unit 50 to the drive motors 41a and 41b between when the subject is imaged through the opening 32c and when the reference chart KC is imaged, the drive motor 41a is changed. , 41b is changed, and the moving direction of the lens 36a is changed.

  The imaging unit 30 has a fan 60 attached to the position side wall surface of the frame 32 between the upper cover 31 and the sensor substrate 33, and the wall surface of the frame 32 to which the fan 60 is attached An air port (air intake port) 61 for taking in external air into the frame body 32 by rotation of the fan 6 is formed. A filter 62 for removing dust in the air taken into the frame 32 from the outside is attached to the air port 61. The fan 60, the air port 61, and the filter 62 as a whole function as air intake means that takes in air outside the frame body 32 into the frame body 32 and injects it from an air injection port 63 described later.

  In the imaging unit 30, an air injection port 63 is formed in a bottom surface portion 32a between the opening 32b and the opening 32c, and the air injection port 63 has a predetermined width at the center in the sub-scanning direction of the bottom surface portion 32a. Thus, it is formed over a predetermined length in the sub-scanning direction. The air injection port 63 is formed in a state where the inside of the frame body 32 communicates with the outside of the frame body 32, and air taken into the frame body 32 from the outside of the frame body 32 by the fan 60 is transferred to the bottom of the frame body 32. The ink is ejected toward the recording medium P. That is, the imaging unit 30 causes the air taken in from the outside through the air port 61 by the rotation of the fan 60 to flow in the frame 32 as indicated by an arrow in FIG. The air is jetted toward the recording medium P at the lower part of 32 to prevent the dust on the recording medium P from being removed, the ink to be dried by the air, and the floating mist from adhering to the recording medium P. The fan 60, the air port 61, and the air injection port 63 function as air injection means for injecting air toward the subject as a whole.

  And this fan 60 is drive-controlled by the fan drive control part 64 (refer FIG. 9) as an injection control means.

  In the imaging unit 30, an optical path length changing member 71 is disposed in the optical path between the recording medium P and the two-dimensional image sensor 35 that has passed through the opening 32c. It is fixed or held on the surrounding frame 32.

  The optical path length changing member 71 has a refractive index n1 and uses a light transmitting member having a length Lp1 in the light transmission direction (hereinafter referred to as the length of the optical path length changing member), and the refractive index n1. And an optical path length change amount (image floating amount) C1 determined by the following equation (1) by the length Lp1 in the light transmission direction.

C1 = Lp1 (1-1 / n1) (1)
The optical path length (focal length) L1 from the imaging surface of the recording medium P to the two-dimensional image sensor 35 of the image sensor unit 34 is given by the following equation (2).

L1 = Lt + Lp1 (1-1 / n1) (2)
Here, Lt is a distance between the top of the lens 36a on the imaging target side and the imaging surface of the recording medium P.

  The imaging unit 30 then matches the optical path length (focal length) L1 from the imaging surface of the recording medium P to the two-dimensional image sensor 35 with the optical path length (focal length) from the reference chart KC to the two-dimensional image sensor 35. Further, the refractive index n1 and the length Lp1 of the optical path length changing member 71 are set. By setting in this way, the focal position of the reference chart KC with respect to the two-dimensional image sensor 35 of the image sensor unit 34 and the focal position of the subject (imaging surface) can be matched.

  Further, the imaging unit 30 uses the illumination light from the same illumination light source 37 as the illumination light that irradiates the imaging surface of the recording medium P through the optical path length changing member 71 and the opening 32c and the illumination light that irradiates the reference chart KC. Thus, the reference chart KC and the imaging surface of the recording medium P can be imaged simultaneously under the same illumination conditions. In addition, the illumination light source 37 is disposed on the center line Lo, which is a substantially intermediate position between the reference chart KC and the recording medium P, and two illumination light sources 37 are disposed on the object on the center line Lo with respect to the lens 36a. The imaging area of the reference chart KC and the recording medium P can be illuminated uniformly under substantially the same illumination conditions.

  Furthermore, since the imaging unit 30 is arranged substantially symmetrically with respect to the center line Lo connecting the center of the lens 36a and the illumination light source 37, the arrangement condition of the opening 32c of the imaging region and the reference chart KC is two-dimensional. The imaging conditions of the image sensor 35 can be made line symmetrical and the same, and the accuracy of color adjustment processing and color measurement processing of the two-dimensional image sensor 35 using the reference chart KC can be improved.

  The image forming apparatus 1 of the present embodiment is configured as a block as shown in FIG. 8, and includes a central processing unit (CPU) 101, a read only memory (ROM) 102, a random access memory (RAM) 103, and main scanning. A driver 104, a recording head driver 105, a colorimetric control unit 106, a paper transport unit 107, a sub-scanning driver 108, and the like are provided, and the recording head 20, the encoder sensor 21, and the imaging device mounted on the carriage 6 as described above A unit 30 and the like are provided.

  The ROM 102 stores programs such as a basic program and a color adjustment processing program as the image forming apparatus 1 and necessary system data. The CPU 101 uses the RAM 103 as a work memory based on the program in the ROM 102, and performs image processing. The respective units of the forming apparatus 1 are controlled to execute basic processing as the image forming apparatus 1 and, at the same time, the colorimetric processing obtained by the colorimetric processing by the colorimetric control unit 106 based on the RGB values captured by the imaging unit 30. Based on the color value, color adjustment processing at the time of image formation is executed. In particular, the CPU 101 performs drive control of the fan 60 in the color adjustment process based on a program in the ROM 102.

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

  As described above, the imaging unit 30 generates a color measurement value for color adjustment that accurately reproduces the color of image data when recording and outputting an image to a color intended by the user, as described later. The color measurement color patch CP formed by the recording head 20 on the recording medium P is imaged at the time of color measurement, and the captured RGB values are output to the CPU 101.

  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, the image sensor unit 34, the lens position adjustment mechanism unit 40, the fan 60, and the image processing unit 110, the interface unit 111, and the like. 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 are provided. The imaging unit 30 and the color measurement control unit 106 function as a color measurement device as a whole.

  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, and the image processing unit 110 receives the analog RGB image data sent from the image sensor unit 34. Necessary image processing is performed on the RGB image data and output to the colorimetric control unit 106.

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

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

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

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

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

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

  The colorimetric control unit 106 includes a lens position adjustment unit 50, a fan drive control unit 64, 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. 124 includes a colorimetric value calculation unit 126.

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

  As shown in FIG. 10, the non-volatile memory 125 includes Lab values that are colorimetric values of colorimetric results of a plurality of reference color patches KP arrayed on the reference sheet KS by the spectroscope (colorimetry device) BS. And at least one of the XYZ values (both Lab and XYZ values in FIG. 10) are stored as reference colorimetric values in the memory table Tb1 of the nonvolatile memory 125 in correspondence with the patch numbers.

  Further, the image forming apparatus 1 stores the reference sheet KS of the image forming apparatus 1 in a state where the reference colorimetric values are stored in the nonvolatile memory 125 in the memory table Tb1 and in the initial state of the image forming apparatus 1. An imaging reference RGB value obtained by setting the same on the platen 14 and reading the same reference patch KP as that read by the spectroscope BS of the reference sheet KS by the imaging unit 30 by controlling the movement of the carriage 6 is stored in the nonvolatile memory 125. Is stored in correspondence with the patch number, that is, in correspondence with the reference colorimetric value, and each patch of the reference chart KC of the imaging unit 30 is imaged to obtain the RGB value. The RGB value of each patch of the chart KC is set as the initial reference RGB value RdGdBd, and the nonvolatile memory 125 is controlled under the control of the calculation unit 124. It is stored in the memory table Tb1.

  When the image forming apparatus 1 stores the reference colorimetric value, the imaging reference RGB value, and the initial reference RGB value RdGdBd in the nonvolatile memory 125, the colorimetric value calculation unit 126 stores the reference colorimetry stored in the nonvolatile memory 125. A reference value linear conversion matrix for mutual conversion is calculated for a pair of XYZ values and imaging reference RGB values, that is, a pair of XYZ values and imaging reference RGB values of the same patch number, and the calculated reference value linear The conversion matrix is stored in the nonvolatile memory 125.

  In the image forming apparatus 1, the above processing is executed in the initial state of the image forming apparatus 1, and the reference colorimetric values, imaging reference RGB values, and initial reference RGB values RdGdBd as execution results are stored in the memory table Tb 1 of the nonvolatile memory 125. Then, a reference value linear transformation matrix is calculated and stored in the nonvolatile memory 125.

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

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

  The lens position adjustment unit 50 is configured by a CPU, ROM, RAM, or a microcomputer chip. The lens position adjustment unit 50 controls a motor drive signal to the lens position adjustment mechanism unit 40 in accordance with the lens position adjustment timing from the CPU 101 based on a lens position adjustment program in a memory such as a ROM, so that the lens position is adjusted. The drive control of the adjustment mechanism unit 40, that is, the rotation drive of the drive motors 41a and 41b is controlled to adjust the position of the lens 36a of the image sensor unit 34.

  The fan drive control unit (injection control means) 64 includes a CPU, ROM, RAM, or a microcomputer chip. The fan drive control unit 64 controls the motor drive signal to the fan 60 according to the fan drive timing from the CPU 101 based on the fan drive control program in the memory such as the ROM and the drive conditions such as the drive frequency and the drive time. Then, drive control of the fan 60 is performed. The driving condition of the fan 60 may be stored in the ROM in advance, which is different between printing and color measurement. Therefore, the image forming apparatus 1 is equipped with a color measurement device including an image pickup unit 30 as an image pickup unit, a color measurement control unit 106 as a calculation unit, and a fan drive control unit 64 as an ejection control unit. Yes.

  The image forming apparatus 1 of this embodiment includes a ROM, an EEPROM (Electrically Erasable and Programmable Read Only Memory), an EPROM, a flash memory, a flexible disk, a CD-ROM (Compact Disc Read Only Memory), and a CD-RW (Compact Disc Rewritable). A color measurement program for executing the color measurement method of this embodiment recorded on a computer-readable recording medium such as a DVD (Digital Versatile Disk), an SD (Secure Digital) card, or an MO (Magneto-Optical Disc). A colorimetric device that executes a colorimetric method for always capturing an image of a subject and a reference chart in a stable positional relationship while preventing dust adhering to be described later by being read and introduced into the ROM 102 or the non-volatile memory 125 is provided. The image forming apparatus 1 is constructed. This color measurement program is a computer-executable program written in a legacy programming language such as assembler, C, C ++, C #, Java (registered trademark) or an object-oriented programming language, and is stored in the recording medium. Can be distributed.

  Next, the operation of this embodiment will be described. The image forming apparatus 1 according to the present embodiment always captures an image of the subject and the reference chart in a stable positional relationship while preventing dust from being attached.

  As shown in FIG. 10, the image forming apparatus 1 according to the present embodiment uses the spectroscope BS to calculate the color measurement results of a plurality of reference color patches arranged and formed on the reference sheet KS, among Lab values and XYZ values. , At least one of them is stored as a reference colorimetric value corresponding to the patch number in the memory table Tb1 of the nonvolatile memory 125.

  Further, when the image forming apparatus 1 is in a state where the reference colorimetric values are stored in the nonvolatile memory 125 in the memory table Tb1 and the image forming apparatus 1 is in an initial state due to manufacture, overfall, or the like, The reference sheet KS is set on the platen 14 of the image forming apparatus 1, the movement of the carriage 6 is controlled, and the same reference patch read by the spectroscope BS of the reference sheet KS is read by the imaging unit 30, and at the same time As shown in FIG. 11, each patch (initial reference color patch) of the reference chart KC arranged inside the frame 32 is imaged.

  When the image forming apparatus 1 captures the reference patch of the reference sheet KS and each patch of the reference chart KC by the imaging unit 30, the image forming apparatus 1 has RGB values obtained by processing the image data obtained by capturing the reference patch of the reference sheet KS by the image processing unit 110. As shown in FIG. 10, the calculation unit 124 of the color measurement control unit 106 associates the imaging reference RGB values, that is, device-dependent signals, with the patch numbers in the memory table Tb1 of the nonvolatile memory 125. That is, the initial reference RGB value RdGdBd, which is the RGB value obtained by reading the initial reference color patch of the reference chart KC and processing it by the image processing unit 110 while storing it in correspondence with the reference colorimetric value, is shown in FIG. As shown in FIG.

  The calculation unit 124 calculates an average value for each predetermined region, for example, a region (color measurement target region) indicated by a broken line in FIG. 11 among the image data of the initial reference color batch of the reference chart KC read by the imaging unit 30. The initial reference RGB value RdGdBd is calculated. When the initial reference RGB value RdGdBd is calculated by averaging a large number of pixels in the colorimetric object region in this way, the influence of noise can be reduced and the bit resolution can be improved. FIG. 12B is a scatter diagram in which the initial reference RGB value RdGdBd is plotted. FIG. 12A is a reference Lab value Lddbdd and XYZ values obtained by converting the initial reference RGB value RdGdBd into Lab values. The reference XYZ value xdydzd also indicates a state registered in the nonvolatile memory 125.

  When the image forming apparatus 1 stores the reference colorimetric value, the imaging reference RGB value, and the initial reference RGB value RdGdBd in the nonvolatile memory 125, the colorimetric value calculation unit 126 of the calculation unit 124 is stored in the nonvolatile memory 125. Calculate a reference value linear conversion matrix for mutual conversion with respect to a pair of XYZ value and imaging reference RGB value of the reference colorimetric value, that is, a pair of XYZ value and imaging reference RGB value of the same patch number The reference value linear transformation matrix is stored in the nonvolatile memory 125.

  In this state, in the image forming apparatus 1, the CPU 101 controls the main scanning movement of the carriage 6, the conveyance control of the recording medium P by the paper conveyance unit 48, and the recording head based on image data input from the outside, print settings, and the like. 20, by controlling the ink ejection from the recording heads 20 y, 20 m, 20 c, and 20 k of the recording head 20 while intermittently transporting the recording medium P by controlling the drive of the recording medium 20, the image is recorded on the recording medium P To do.

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

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

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

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

  When forming the color measurement adjustment color patch CP on the color measurement adjustment sheet CS, the image forming apparatus 1 outputs a fan drive signal to the fan 60 based on the drive timing from the CPU 101, and only for a predetermined drive time. For example, the fan 60 is driven by outputting a fan drive signal to the fan 60 only while the carriage 6 is moving.

  When the fan 60 is rotationally driven, the imaging unit 30 circulates the air taken into the frame body 32 from the air port 61 through the filter 62 by the fan 60 through the frame body 32 as indicated by arrows in FIG. The air is injected below the frame 32 from the air injection port 63 formed at the center of the bottom surface portion 32 a of the frame 32. The air ejected from the air ejection port 63 passes between the colorimetric adjustment sheet CS and the outer surface of the bottom surface portion 32a of the frame body 32 as shown by an arrow in FIG. Prevents ink mist, dust, and the like from adhering to the optical path length changing member 71 that faces the opening 32c that is jetted and affects the colorimetry of the image pickup unit 30, and prevents the influence of foreign matters such as dust from entering the imaging result. And the colorimetric accuracy can be improved.

  In addition, since the color of the color measurement adjustment color patch CP formed by the ink ejection method changes before and after the ink is ejected and dried, the color measurement is usually performed after the ink is dried. As described above, the image forming apparatus 1 according to the present embodiment rotates the fan 60 when the colorimetric adjustment color patch CP is formed by ejecting ink while moving the carriage 6 as described above. Since the air is ejected from the air ejection port 63 to the color measurement adjustment sheet CS on which the color measurement adjustment color patch CP is formed, the drying of the ink can be promoted, and the ink is dried and the color measurement is performed. It is possible to shorten the waiting time until the operation is performed.

  The image forming apparatus 1 captures the reference color patch KP of the reference sheet KS with the imaging unit 30 as described above and captures each colorimetric adjustment color patch CP of the colorimetry adjustment sheet CS as an imaging target. In addition, each patch of the reference chart KC attached to the frame 32 is imaged. At this time, in order to image each patch with high accuracy, the reflected light from each patch is converted into the two-dimensional image of the image sensor unit 34. The lens position adjusting mechanism unit 40 changes and adjusts the position of the lens 36 a that collects light on the image sensor 35 under the control of the lens position control unit 50.

  That is, in the image forming apparatus 1, when it is time to capture the reference color patch KP of the reference sheet KS and the color measurement adjustment color patch CP of the color measurement adjustment sheet CS, first, the lens position control unit 50 of the color measurement control unit 106 is started. In the initial state, the position of the lens 36a is set at the position where the patch of the reference chart KC is imaged. In this state, the image pickup unit 30 measures the reference color patch KP of the reference sheet KS or the colorimetric adjustment sheet CS. It moves to the imaging position of the color adjustment color patch CP (hereinafter referred to as imaging target as appropriate).

  When the image forming apparatus 1 moves the imaging unit 30 to the imaging position of the imaging target, first, the image of the patch of the reference chart KC is imaged, and when the imaging of the predetermined patch of the reference chart KC is completed, then the lens position control unit 50, a motor drive signal is output, the drive motors 41a and 41b are synchronously rotated in the same direction, and the guide rails 42a and 42b to which the lens holder 43 is attached are synchronously rotated in the same direction. The position of the lens holder 43 that holds the lens 36a, that is, the position of the lens 36a is adjusted from the reference chart imaging position to the imaging target imaging lens position.

  That is, when imaging the reference chart KC, the distance between the reference chart KC and the lens 36a is ak, the distance between the lens 36a and the two-dimensional image sensor 35 is bk, and the distance between the reference chart KC and the two-dimensional image sensor 35 is Lk. When the focal length of the lens 36a is f, there is a relationship between them as shown in the following equation.

ak + bk = Lk
1 / ak + 1 / bk = 1 / f (3)
When the imaging target is imaged through the opening 32c, the distance between the imaging target and the lens 36a is as, the distance between the lens 36a and the two-dimensional image sensor 35 is bs, and the distance between the imaging target and the two-dimensional image sensor 35 is set. Assuming Ls, the focal length f of the lens 36a and the relationship between them are as shown in the following equation.

as + bs = Ls
1 / as + 1 / bs = 1 / f (4)
Therefore, the positional difference Δd between the position of the lens 36a when imaging the reference chart KC and the position of the lens 36a when imaging the imaging target can be obtained by the following equation (5).

Δd = bk−bs (5)
When the position of the imaging target lens is adjusted in step S103, the image forming apparatus 1 causes the imaging unit 30 to perform imaging of the imaging target, and outputs a motor drive signal from the lens position control unit 50 to drive motors 41a and 41b. Is rotated to rotate the guide rails 42a and 42b to which the lens holder 43 is attached, whereby the position of the lens holder 43 that holds the lens 36a, that is, the position of the lens 36a is determined from the imaging target imaging lens position. Position adjustment to return to the reference chart imaging position is performed.

  The CPU 101 captures the entire range required for the imaging target and the reference chart KC while adjusting the position of the lens 36a.

  Then, as shown in FIG. 13, the image forming apparatus 1 sets the colorimetric adjustment sheet CS on the platen 14 or does not eject the colorimetric adjustment sheet CS when it is recorded. As a held state, a plurality of color measurement adjustment color patches CP of the color measurement adjustment sheet CS on the platen 14 are imaged by the imaging unit 30 while controlling the movement of the carriage 6 and at the same time, Capture the patch. Even when the carriage 6 moves, the fan 60 may be driven so that air is ejected from the air ejection port 63 toward the colorimetric adjustment sheet CS. In this way, it is possible to prevent the paper struggling garbage subject to the movement of the image pickup unit 30 from adhering to the image pickup unit 30.

  When the image forming apparatus 1 simultaneously captures the color measurement adjustment color patch CP of the color measurement adjustment sheet CS and the patch of the reference chart KC by the image pickup unit 30, the image processing unit 110 of the image pickup unit 30 measures the color measurement adjustment sheet CS. After the necessary image processing is performed on the image data of the color adjustment color patch CP and the image data of the reference chart KC, the image data (RGB values) of the color measurement adjustment color patch CP of the color measurement adjustment sheet CS is obtained. The colorimetric target RGB values, that is, device-dependent signals dependent on the device, and the image data (RGB values) of the patches of the reference chart KC are sent to the colorimetry control unit 106 as colorimetric reference RGB values RdsGdsBds, As shown in FIG. 13, the colorimetric control unit 106 temporarily stores it in the frame memory 121 shown in FIG. 9 (step S11).

  Then, the colorimetric control unit 106 initializes the colorimetric RGB value stored in the frame memory 121 by the colorimetric value calculation unit 126 of the calculation unit 124 using a reference RGB linear conversion matrix described later. The color target RGB value RsGsBs is converted (steps S12 and S13).

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

  In the image forming apparatus 1 according to the present exemplary embodiment, the colorimetric value calculation unit 126 of the calculation unit 124 obtains the reference RGB linear conversion matrix as illustrated in FIGS. 14 and 15.

  That is, as shown in FIG. 14, the calorimetric value calculation unit 126 of the calculation unit 124 captures the patch of the reference chart KC at the same time when the imaging unit 30 captures the reference color patch KP of the reference sheet KS at the initial stage. When the initial reference RGB value RdGdBd stored in the nonvolatile memory 125 and the color measurement adjustment color patch CP of the color measurement adjustment sheet CS are imaged by the imaging unit 30 during color measurement, the patch of the reference chart KC is simultaneously captured. Then, the colorimetric reference RGB value RdsGdsBds stored in the nonvolatile memory 125 is read from the nonvolatile memory 125, and the colorimetric reference RGB value RdsGdsBds is converted into the initial reference RGB value RdGdBd. The reference RGB linear conversion matrix is stored in the nonvolatile memory 125. To.

  That is, in FIG. 15, the points indicated by white dots in FIG. 15A are points where the initial reference RGB values RdGdBd are plotted in the rgb space, and the fill points are the colorimetric reference RGB values RdsGdsBds as rgb. This is a point plotted in space. As can be seen from FIG. 15A, the value of the colorimetric reference RGB value RdsGdsBds fluctuates from the value of the initial reference RGB value RdGdBd, and the fluctuation direction in the rgb space is shown in FIG. 15B. As indicated by the arrows, the directions are generally the same, but the direction of deviation differs depending on the hue. As described above, the reason why the RGB values fluctuate even when the patches of the same reference chart KC are imaged includes a change with time of the illumination light source 37 and a change with time of the two-dimensional image sensor 35.

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

  In view of this, the image forming apparatus 1 according to the present exemplary embodiment uses the estimation method such as the least square method between the initial reference RGB value RdGdBd and the colorimetric reference RGB value RdsGdsBds to initially set the colorimetric reference RGB value RdsGdsBds. A reference RGB linear conversion matrix to be converted into the reference RGB value RdGdBd is obtained, and the color measurement adjustment color patch CP of the color measurement adjustment sheet CS is imaged by the imaging unit 30 using the reference RGB linear conversion matrix, and the nonvolatile memory is used. The colorimetric object RGB values stored in 125 are converted into initialization colorimetry object RGB values RsGsBs, and the converted initial colorimetry object RGB values RsGsBs are used as colorimetry object RGB values to be described later. To obtain Lab colorimetric values.

  This linear conversion matrix between RGB may be not only a first-order but also a higher-order nonlinear matrix. If the nonlinearity is high between the rgb space and the XYZ space, a higher-order matrix can be obtained. , Conversion accuracy can be improved.

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

  Furthermore, the imaging unit 30 includes an optical path length in the optical path between the reference color patch KP of the reference sheet KS as the subject and the color measurement adjustment color patch CP of the color measurement adjustment sheet CS and the two-dimensional image sensor 35 through the opening 32c. A change member 71 is provided, and the optical path length (focal length) L1 from the color measurement adjustment color patch CP of the color measurement adjustment sheet CS that is the subject to the image sensor unit 34 and the reference chart KC to the image sensor unit 34. The refractive index n1 and length Lp1 of the optical path length changing member 71 are set so that the optical path length (focal length) L2 matches, and the focal position of the reference chart KC relative to the image sensor unit 34 and the subject (reference sheet KS) The focal positions of the reference color patch KP and the colorimetric adjustment color patch CP) of the colorimetric adjustment sheet CS can be matched.

  Therefore, the reference color patch KP of the reference sheet KS, the colorimetric adjustment color patch CP of the colorimetry adjustment sheet CS, and the reference chart KC to be compared between them are always stably imaged with high accuracy and the same accuracy. Can do.

  Further, the imaging unit 30 uses the illumination light from the same illumination light source 37 as the illumination light that irradiates the imaging surface of the recording medium P through the optical path length changing member 71 and the opening 32c and the illumination light that irradiates the reference chart KC. Thus, the reference chart KC and the imaging surface of the recording medium P can be imaged simultaneously under the same illumination conditions. In addition, the illumination light source 37 is disposed on the center line Lo which is a substantially intermediate position between the reference chart KC and the recording medium P, and two illumination light sources 37 are disposed on the center line Lo with respect to the lens 36. The imaging area of the reference chart KC and the recording medium P can be illuminated uniformly under substantially the same illumination conditions.

  Furthermore, since the imaging unit 30 is arranged substantially symmetrically with respect to the center line Lo connecting the center of the lens 36a and the illumination light source 37, the arrangement condition of the opening 32c of the imaging region and the reference chart KC is two-dimensional. The imaging conditions of the image sensor 35 can be made line symmetrical and the same, and the accuracy of color adjustment processing and color measurement processing of the two-dimensional image sensor 35 using the reference chart KC can be improved.

  Then, when the image forming apparatus 1 obtains the initial colorimetric target RGB value RsGsBs as described above and sets it as the colorimetric target RGB value, the memory table Tb1 of the nonvolatile memory 125 as shown in FIGS. Of the colorimetric values registered in the colorimetric object RGB values, the reference colorimetric values (neighboring reference colorimetric values) that are close in distance to the colorimetric values converted into the colorimetric object RGB values are selected and measured. A basic colorimetry process for obtaining a colorimetric value for converting a color target RGB value to a selected neighborhood reference colorimetric value is executed, and recording is performed based on image data after color conversion is performed based on the colorimetric value. By outputting an image by the head 20, the color reproducibility of the image formed by the image forming apparatus 1 is improved. When the ink is ejected from the recording head 20 to form an image, the fan 60 may be driven to rotate to eject air from the air ejection port 63. In this way, it is possible to prevent ink mist and dust from adhering to the surface of the frame 32 and the optical path length changing member 71 and to prevent ink mist and dust from entering the frame 32 from the air ejection port 63. Can be prevented.

  That is, as shown in FIG. 16, the image forming apparatus 1 captures the color measurement adjustment color patch CP of the color measurement adjustment sheet CS, obtains the initial color measurement target RGB value RsGsBs as described above, and determines the color measurement target RGB. When stored in the nonvolatile memory 125 as a value (step S21), the reference value linear conversion matrix is used (step S22), converted into a first XYZ value (step S23), and stored in the nonvolatile memory 125 (step S22). S24). For example, in FIG. 16, the colorimetric value calculation unit 126 converts the RGB values (3, 200, 5) of the imaging unit 30 into the first XYZ values (first colorimetric values) of (20, 80, 10). And stored in the nonvolatile memory 125.

  The colorimetric value calculation unit 126 converts the first XYZ value into a first Lab value (first colorimetric value) by referring to the memory table Tb1 of the nonvolatile memory 125 or using a known conversion formula. (Step S25), stored in the nonvolatile memory 125 (Step S26). For example, in FIG. 16, the colorimetric value calculation unit 126 converts the first XYZ value (20, 80, 10) into the first Lab value (75, −60, 8) that is the imaged colorimetric value.

  Next, the colorimetric value calculation unit 126 searches for the reference colorimetric values (Lab values) of the color patches of the plurality of colors in the memory table Tb1 stored in the nonvolatile memory 125, as indicated by the Lab space in FIG. Then, a set of color patches (neighboring color patches) that are close in distance to the first Lab value in the Lab space is selected from the reference colorimetric values (Lab values) (step S27). For example, the Lab space diagram of FIG. 16 shows a diagram in which 60 color patches are selected and plotted on the Lab space. For example, the first Lab can be selected as a method for selecting a patch having a short distance. The distance between the value and all points in the reference colorimetric values (Lab values) of the plurality of color patches is calculated, and the reference Lab value of the color patch that is close to the first Lab value that is the first colorimetric value ( In FIG. 16, a reference Lab value (hatched) is selected.

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

  The colorimetric value calculation unit 126 captures each colorimetric adjustment color patch CP of the colorimetry adjustment sheet CS that is a colorimetric object by the imaging unit 30 and digitally converts the colorimetric object RGB value by the A / D converter 36. A second XYZ value, which is a second colorimetric value, is obtained using the selected RGB value linear conversion matrix (step S30), and the second XYZ value is converted into a second Lab value using a known conversion formula (step S31). Obtained as a final colorimetric value (step S32).

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

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

  In the above description, the imaging unit 30 has the air injection port 63 formed at the center of the bottom surface portion 32a. However, the formation position of the air injection port 63 is not limited to the above position. It is not necessary to form the injection port 63 only on the bottom surface portion 32a. For example, as shown in FIGS. 18 and 19, the position of the communication port 32f and the corresponding lower center portion of the optical path length changing member 71 at the center portion of the bottom surface portion 32a. Alternatively, the inclined surface 71a may be formed, and the inclined air injection port 65 communicating with the opening 32c and the inside of the frame body 32 may be formed.

  In this case, the imaging unit 30 circulates the air taken into the frame body 32 by the fan 60 from the air port 61 through the filter 62 in the frame body 32 as shown by arrows in FIG. It injects toward the downward direction of the frame 32 from the inclination air injection port 65 formed in the center part of the bottom face part 32a, especially the downward direction of the opening part 32c. As shown by arrows in FIG. 18, the air injected from the inclined air injection port 63 is between the color measurement adjustment sheet CS and the outer surface of the bottom surface portion 32 a of the frame body 32, particularly the opening 32 c and the color measurement adjustment sheet. Ink mist, dust, or the like adheres to the optical path length changing member 71 that passes through the CS and is injected to the side of the frame 32 and faces the opening 32c that affects the color measurement of the imaging unit 30. Can be prevented more efficiently, and the colorimetric accuracy can be further improved.

  As described above, in the image forming apparatus 1 of this embodiment, the imaging unit 30 is the imaging unit 30 having the image sensor unit (sensor means) 34 that images a predetermined area including the subject, and the imaging unit 30 is within the area. A reference chart KC that is arranged and imaged by the image sensor unit 34 together with the subject located outside the imaging unit 30, and a fan 60 as air ejecting means that ejects air from the inside of the imaging unit 30 toward the subject. , An air port 61 and an air injection port 63.

  Therefore, it is possible to prevent ink mist and dust from adhering to the imaging unit 30 and the subject, and to prevent the influence of foreign matters such as dust from entering the imaging result by the image sensor unit 34, and to the subject and the reference chart KC. Can be simultaneously and stably imaged, and the subject and the reference chart KC can always be imaged with a stable positional relationship with high accuracy.

  Further, the imaging unit 30 of the present embodiment includes a frame 32 provided with an opening 32c for the image sensor unit 34 to image the subject, and the air ejecting means is formed in the vicinity of the opening 32c. An air injection port 63 for communicating the inside of the body 32 with the outside of the frame body 32 at the portion facing the subject, and an air intake means for taking in the air outside the frame body 32 into the frame body 32 and injecting it from the air injection port 63 As a fan 60, an air port 61, and a filter 62.

  Therefore, air can be ejected toward the subject with a simple configuration, and ink mist and dust can be prevented from adhering to the subject and the imaging unit 30 at a low cost, and the image sensor unit 34 can collect dust. The object and the reference chart KC can be captured at the same time and stably so that the object and the reference chart KC are always in a stable positional relationship. Images can be taken with high accuracy.

  Further, in the imaging unit 30, the air intake means includes an air port (air intake port) 61 formed in the frame body 32, and an air outside the frame body 32 from the air port 61. And a filter 62 that is disposed in the air port 61 and cleans the air taken into the frame body 32 by the fan 60.

  Accordingly, air can be ejected toward the subject with a simple configuration, and ink mist and dust can be prevented from being attached to the subject and the imaging unit 30 at low cost and easily. Can be imaged simultaneously and stably, and the subject and the reference chart KC can always be imaged with a stable positional relationship with high accuracy.

  Further, in the imaging unit 30, the air injection port 63 is formed in the bottom surface portion 32a that is a facing surface between the opening portion 32c of the frame body 32 and the reference chart KC.

  Therefore, air can be ejected toward the subject with a simpler configuration, and ink mist and dust can be prevented from being attached to the subject and the imaging unit 30 at low cost and easily. The KC can be imaged simultaneously and stably, and the subject and the reference chart KC can always be imaged with high accuracy in a stable positional relationship.

  Further, the imaging unit 30 includes an optical path length changing member 71 that is disposed on the bottom surface portion 32a that is the opposing surface in a state of closing the opening 32c, and has a predetermined optical path length changing amount, and the air injection port 63 includes: At the end position on the reference chart KC side of the opening 32c on which the optical path changing member 71 of the bottom surface portion 32a is placed, at least one of the optical path length changing member 71 and the bottom surface portion 32a, The outside of the frame body 32 is communicated, and is formed so as to open from the inside of the frame body 32 to the outside of the frame body 32 toward the optical path length changing member 71.

  Accordingly, air can be jetted between the optical path length changing member 71 and the subject, and ink mist and dust can be more appropriately prevented from adhering to the subject and the imaging unit 30, and the subject and The reference chart KC can be imaged simultaneously and stably, and the subject and the reference chart KC can always be imaged with high accuracy in a stable positional relationship.

  Further, in the above description, the color measurement process is performed by the color measurement control unit 106 of the image forming apparatus 1. However, the color measurement process does not need to be executed inside the image forming apparatus 1. For example, FIG. As shown, an image forming apparatus 210 is connected to an external apparatus 220 as an image forming system (colorimetry system) 200, and image data captured by the image forming apparatus 210 is output to the external apparatus 220. The external device 220 performs color adjustment processing that includes colorimetric processing, and outputs the color-adjusted image data to the image forming device 210. The image forming device 210 forms an image based on the image data from the external device 220. May be.

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

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

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

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

  The external device (calculation means, ejection control means) 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 with color measurement processing of the present invention, and necessary data in the hard disk 229. Alternatively, the image data is stored in the ROM 227, and the CPU 221 controls the image forming apparatus 210 based on the program in the ROM 227 or the hard disk 229, thereby executing basic processing as the image forming apparatus 210 and performing the colorimetric processing of the present invention. The accompanying color adjustment process and the air injection control process for controlling the driving of the fan 60 as the air injection means are executed.

  The hard disk 229 stores the above program and various data necessary for executing the color adjustment processing, in particular, the colorimetry of the plurality of reference color patches KP arranged on the reference sheet KS described in the above embodiment. Of the resulting Lab value and XYZ value, at least one of the reference patch KP of the reference sheet KS is read by the image pickup unit 30 of the image forming apparatus 210. Table and selected RGB value linear conversion matrix, initial reference RGB value RdGdBd of each color patch of the reference chart KC read simultaneously with the reference sheet KS, and reference read simultaneously when the colorimetric adjustment color patch CP of the colorimetry adjustment sheet CS is read Reference RGB value RdsGdsBds and colorimetry at the time of color measurement of the reference patch of chart KC Reference RGB between linear transformation matrix to convert the initial reference RGB value RdGdBd is stored a reference RGB values RdsGdsBds.

  The communication I / F unit 224 is connected to an image processing apparatus such as a scanner apparatus, a composite apparatus, or another external apparatus via a line such as a network, and receives image data that causes the image forming apparatus 210 to output an image. The I / F unit 213, the I / F unit 224, and the line 230 function as a communication unit as a whole.

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

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

  In the image forming system 200 of FIG. 23, 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. The external device 220 may execute only the color measurement process for which the controller controls and obtains the color measurement value, or only the color adjustment process including the color measurement process.

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

  In the above description, the case where the sensor substrate 33 is smaller than the frame body 32 has been described. However, the sensor substrate 33 may be of a size that blocks the frame body 32. A ventilation hole is formed so that the air taken into the body 32 flows to the air injection port 63.

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

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Main body case 3 Main body frame 4 Main guide rod 5 Sub guide rod 6 Carriage 6a Connection piece 7 Timing belt 8 Drive pulley 9 Driven pulley 10 Main scanning motor 11 Cartridge part 12 Maintenance mechanism part 13 Cover 14 Platen 20, 20y, 20m, 20c, 20k Recording head 21 Encoder sensor 30 Imaging unit 31 Upper cover 32 Frame body 32a Bottom surface portion 32b Opening portion 32c Opening portion 32d Recessed portion 32e Holding plate 32f Communication port 33 Sensor substrate 34 Image sensor portion 35 Two-dimensional image sensor 36 Lens unit 36a Lens 37 Illumination light source 40 Lens position adjustment mechanism 41a, 41b Drive motor 42a, 42b Guide rail 43 Lens holder 50 Lens position adjustment 60 Fan 61 Air port 62 Filter 63 Air injection port 64 Fan drive control unit 65 Inclined air injection port 71 Optical path length changing member 71a Inclined surface 101 CPU
102 ROM
103 RAM
104 Main Scan Driver 105 Recording Head Driver 106 Colorimetry Control Unit 107 Paper Transport Unit 108 Sub Scan Driver 110 Image Processing Unit 111 Interface Unit 112 A / D Conversion Unit 113 Shading Correction Unit 114 White Balance Correction Unit 115 γ Correction Unit 116 Image Format Conversion unit 121 Frame memory 122 Timing signal generation unit 123 Light source drive control unit 124 Calculation unit 125 Non-volatile memory 126 Colorimetric value calculation unit 200 Image forming system 210 Image forming apparatus 211 Engine 212 Operation display unit 213 I / F unit 214 Others I / F unit 215 Bus 220 External device 221 CPU
222 Memory unit 223 Image processing unit 224 Communication I / F unit 225 I / F unit 226 Bus 227 ROM
228 RAM
229 Hard disk 230 Line Lo Center line KS Reference sheet KP Reference color patch CS Color measurement adjustment sheet CP Color measurement adjustment patch KC Reference chart Pa to Pd Reference color patch row Pe Dot diameter measurement pattern row lk Distance measurement line mk Chart position specification Marker Tb1 memory table

JP 2012-063270 A

Claims (9)

An imaging unit having sensor means for imaging a predetermined area including a subject,
A reference chart arranged in the region and imaged by the sensor means together with the subject located outside the imaging unit;
Air jetting means for jetting air from the inside of the imaging unit toward the subject;
An imaging unit comprising: The imaging unit is
The sensor means comprises a frame provided with an opening for imaging the subject;
The air injection means is
An air injection port that is formed in the vicinity of the opening and communicates between the frame and the outside of the frame facing the subject;
Air intake means for taking in air outside the frame and injecting it from the air injection port;
The imaging unit according to claim 1, further comprising: The air intake means is
An air intake port formed in the frame;
A fan that is disposed in the air intake port and takes air outside the frame body into the frame body from the air intake port;
A filter that is disposed in the air intake port and cleans the air taken into the frame by the fan;
The imaging unit according to 2, wherein the imaging unit is provided. The reference chart is
Provided side by side with the opening in the predetermined range,
The air injection port is
The imaging unit according to claim 2, wherein the imaging unit is formed on the facing surface between the opening and the reference chart. The imaging unit is
An optical path length changing member disposed on the facing surface in a state of closing the opening and having a predetermined optical path length changing amount;
The air injection port is
At least one of the optical path length changing member and the opposing surface at the end position on the reference chart side of the opening on which the optical path length changing member on the opposing surface is placed, the frame pair inside and the frame 4. The imaging unit according to claim 2, wherein the imaging unit is formed in a state of communicating outside the body and opening from the inside of the frame to the outside of the frame toward the direction of the optical path length changing member. An imaging means for simultaneously imaging a reference chart composed of a plurality of colors and an arbitrary subject;
Calculation means for calculating a colorimetric value of the subject based on the subject imaged by the imaging means and imaging data of the reference chart;
Injection control means for causing the air injection means to inject air at a predetermined timing;
A colorimetric device comprising:
A colorimetric apparatus comprising the imaging unit according to claim 1 as the imaging unit. The imaging means includes
Moving on the subject to image the subject,
The air injection means is
The colorimetric apparatus according to claim 6, wherein air is jetted at least at a timing when the imaging unit moves on the subject. An imaging means for simultaneously imaging a reference chart composed of a plurality of colors and an arbitrary subject;
Calculation means for calculating a colorimetric value of the subject based on the subject imaged by the imaging means and imaging data of the reference chart;
Injection control means for causing the air injection means to inject air at a predetermined timing;
Communication means for connecting the imaging means, the calculation means and the injection control means;
A colorimetric system comprising:
A colorimetry system comprising the imaging unit according to claim 1 as the imaging unit. An image forming apparatus that forms an image using image data that has been color-adjusted based on a colorimetric value measured by a colorimeter,
An image forming apparatus comprising the color measuring device according to claim 6 or 7 as the color measuring device.