JP2021096312A - Measuring unit and image forming apparatus - Google Patents

Abstract

To reduce the time required for measurement of a color chart.SOLUTION: A measuring unit 500 comprises: conveying sections 420, 421 that convey a color chart 212 on which a patch image 520 is formed in a conveyance direction CD; a measuring section 551 that measures the color of the patch image formed on the color chart; a moving section 575 that moves the measuring section in a movement direction MD orthogonal to the conveyance direction along a surface of the color chart; and a control section 561 that acquires information on the arrangement position of the patch image formed on the color chart from an external device. The control section switches the speed of the measuring section moved by the moving section between a first speed and a second speed faster than the first speed based on the arrangement position information.SELECTED DRAWING: Figure 7

Description

The present invention relates to a measuring unit and an image forming apparatus for measuring the color of an image formed on paper.

Conventionally, there is a color proofer that outputs a color chart as a printed image on which a patch image is formed, measures the density and color value of the output color chart, and performs color calibration. Patent Document 1 discloses a color proofer that has a color sensor that can move in a direction orthogonal to the transport direction of the color chart, and measures density and chromaticity by the color sensor at a predetermined position on the color chart. The color proofer of Patent Document 1 makes it possible to automatically measure a color chart on which a large number (1000 to 2000) of color patches are printed by one color sensor. The color chart is automated because more than 1000 patch images (eg, 1617 patch images are standardized according to ISO12642) are formed, but the measurement takes a lot of time. Therefore, in Patent Document 2, by analyzing the color combination used in the printed image and determining the patch image to be used for the color chart, sufficient quality as an actual image can be obtained apart from the color proofing for authentication. We are proposing a technology that can be secured and shortens the work time.

Japanese Unexamined Patent Publication No. 11-326056 Japanese Unexamined Patent Publication No. 2008-187214

As disclosed in Patent Document 2, in order to shorten the time required for measurement, it is also a necessary technique to limit the patch image to match the actual image. By performing the color management work before or during printing, the color reproducibility of the image forming apparatus can be kept stable. However, in order to increase the productivity of the entire workflow required in the digital printing market these days, it is required to further reduce the measurement time. One of the factors that takes time for measurement is the movement time of the color sensor.

In order to solve the above problems, the measuring unit according to the embodiment of the present invention is used.
A transport unit that transports the color chart on which the patch image is formed in the transport direction,
A measuring unit that measures the color of the patch image formed on the color chart, and
A moving unit that moves the measuring unit in a moving direction orthogonal to the transport direction along the surface of the color chart, and a moving unit.
A control unit that acquires placement position information of the patch image formed on the color chart from an external device, and
With
The control unit is characterized in that the moving speed of the measuring unit by the moving unit is switched between a first speed and a second speed faster than the first speed based on the arrangement position information.

According to the present invention, the moving speed at which the measuring unit for measuring the color of the patch image formed on the color chart moves with respect to the color chart can be switched between the first speed and the second speed. As a result, the time required for color measurement can be shortened and productivity can be improved.

Sectional view of the adjustment unit. Sectional view of image forming apparatus. Explanatory drawing of the measuring part. Explanatory drawing of the measuring unit. Block diagram of the control unit. The figure which shows a normal printing paper and a color chart. A timing chart showing speed switching of the measuring unit 551. The figure which shows the arrangement position information of a reference patch and a color patch on a color chart. A flow chart showing a color measurement operation.

(Adjustment unit)
FIG. 1 is a cross-sectional view of the adjustment unit 400. The adjustment unit 400 is a measuring unit having a color sensor (hereinafter referred to as a measuring unit) 551 capable of moving on the color chart in order to measure the color (density and / or color value) of the printed color chart. It is a color measuring device provided with 500. The measuring unit 551 can move along the surface of the color chart in the moving direction MD (FIG. 4) orthogonal to the transport direction CD of the color chart. The transport rollers 401, 402, and 404 are transport units for transporting paper on which a normal image is formed by an image forming apparatus 100 (FIG. 2) such as a printer. The transport rollers 401, 402, 405, 406, and 407 are transport units that transport the color chart printed by the image forming apparatus 100 (FIG. 2) for color measurement.

The transport path switching member 403 switches the transport path between the first discharge path 411 provided with the transport roller 404 and the second discharge path 412 provided with the transport roller 405. When the adjustment unit 400 is connected to the housing 101 (FIG. 2) of the image forming apparatus 100, the transport path switching member 403 first uses ordinary printing paper on which an image is formed on the paper 110 by the image forming apparatus 100. The transport path is switched so as to transport to the discharge path 411 of. The transport path switching member 403 transports the color chart in which the patch image for color measurement is formed on the paper 110 by the image forming apparatus 100 so as to be transported to the second discharge path 412 so as not to be mixed with the normal print paper. Switch the road. A paper sensor 410 is provided upstream of the measuring unit 500 in the transport direction CD. The paper sensor 410 detects the paper or color chart conveyed by the transfer roller 401.

Next, the operation of the adjustment unit 400 to measure the color chart will be described. When the paper sensor 410 detects the tip of the color chart conveyed by the transfer roller 401, the transfer rollers 401 and 402 then transfer the color chart by a predetermined distance and then stop. The predetermined distance is set so that the patch image formed on the color chart falls within the readable area of the measurement unit 551 when the color chart is stopped. With the transport rollers 401 and 402 stopped, the patch image is measured while moving the measuring unit 551 in the moving direction MD (FIG. 4). After the measurement of the patch image is completed, the transfer rollers 401 and 402 are rotated again to transfer the color chart, and when the next patch image formed on the color chart enters the readable area of the measurement unit 551, the transfer is performed. Stop the rollers 401 and 402. Then, the next patch image is measured while moving the measuring unit 551 in the moving direction MD (FIG. 4). This operation is repeated to measure all the patch images formed on the color chart. After the measurement of all patch images is completed, the color chart is conveyed through the second discharge path 412 by the transfer rollers 405, 406 and 407, and is discharged to the discharge tray 413 provided on the upper part of the adjustment unit 400.

(Image forming device)
Next, the image forming apparatus 100 will be described with reference to FIG. FIG. 2 is a cross-sectional view of the image forming apparatus 100. The image forming apparatus 100 is a laser beam printer that forms an image on paper as a recording medium by using an electrophotographic method. However, the image forming apparatus 100 is not limited to this, and may be an inkjet printer or a sublimation printer. The image forming apparatus 100 includes a housing (main body) 101. The housing 101 is connected to the adjustment unit 400. The adjustment unit 400 is connected to the aftertreatment device 600. The housing 101 is provided with each mechanism constituting the engine unit (image forming unit) 200 and the control board storage unit 104. The control board storage unit 104 houses an engine control unit 102 and a printer controller 103 that control each printing process process (for example, feeding process) by each mechanism.

The engine unit 200 has four stations 120, 121, 122 and 123. Stations 120, 121, 122 and 123 as toner image forming means form a yellow toner image, a magenta toner image, a cyan toner image and a black toner image, respectively. Stations 120, 121, 122 and 123 have substantially the same structure except for the color of the toner.

The photosensitive drum 105 as an image carrier is rotatable. The primary charger 111 uniformly charges the surface of the photosensitive drum 105. The laser scanner unit 107 irradiates the surface of the uniformly charged photosensitive drum 105 with laser light to form an electrostatic latent image on the surface of the photosensitive drum 105. The developer 112 develops an electrostatic latent image with toner as a developer to form a toner image. A voltage having a polarity opposite to that of the toner image is applied to the primary transfer roller 118 to transfer the toner image to the intermediate transfer body 106. The yellow toner image, magenta toner image, cyan toner image, and black toner image formed by the stations 120, 121, 122, and 123 are sequentially transferred onto the intermediate transfer body 106. As a result, a full-color visible image is formed on the intermediate transfer body 106.

The paper (sheet) 110 is conveyed from the storage 113 to the secondary transfer unit 114. A bias having a polarity opposite to that of the toner is applied to the secondary transfer unit 114 to transfer the toner image on the intermediate transfer body 106 to the paper 110. The toner image transferred to the paper 110 is heated and pressurized by the first fixing device 150 and the second fixing device 160, and is fixed to the paper 110. As a result, a color image is formed on the paper 110. The housing 101 of the image forming apparatus 100, the adjusting unit 400, and the post-processing apparatus 600 are electrically and mechanically connected. The paper 110 on which the image is formed by the image forming apparatus 100 is conveyed to the adjusting unit 400, and then is conveyed from the adjusting unit 400 to the post-processing apparatus 600. The post-processing device 600 performs various bookbinding processes such as fastening a plurality of sheets of paper 110 with staples and bundling them.

The image forming apparatus 100 can create a color chart by forming a color measurement patch image (toner patch) 520 (FIG. 3) for measuring the color of an image by the adjusting unit 400 on the paper 110. The paper 110 or color chart on which the patch image is formed is conveyed to the adjustment unit 400. After the color chart is measured by the adjustment unit 400, the color chart is discharged to the discharge tray 413 above the adjustment unit 400 without being conveyed to the aftertreatment device 600. In this way, by providing the discharge port for the color chart separately from the discharge port for the normal print paper, the normal print paper and the color chart can be discharged even when the color adjustment is executed during the print job. Can be prevented from being mixed in.

(Measurement unit)
The measuring unit 551 is a color sensor that measures the color of the image formed on the paper 110. Hereinafter, the measuring unit 551 provided in the measuring unit 500 will be described with reference to FIG. FIG. 3 is an explanatory diagram of the measuring unit 551. The measuring unit 551 includes a white LED 501, a lens 506, a diffraction grating 502, a line sensor 503, a calculation unit 504, and a memory 505. The white LED 501 is a light emitting element that irradiates the patch image 520 and the paper 110 formed on the paper 110 with light. The lens 506 collects the light emitted from the white LED 501 on the patch image 520 and the paper 110, and collects the light reflected from the patch image 520 and the paper 110 on the diffraction grating 502. The lens 506 may be omitted.

The diffraction grating 502 is a spectroscopic component that disperses the light reflected from the patch image 520 and the paper 110 for each wavelength. The line sensor 503 (503-1 to 503-n) is a photodetector element having n pixels (light receiving elements) that detect light decomposed for each wavelength by a diffraction grating 502. The calculation unit 504 performs various calculations from the light intensity value of each pixel detected by the line sensor 503. The memory 505 stores various data used by the calculation unit 504. The calculation unit 504 has, for example, a function of calculating a Lab value representing a spectral reflectance or a color value from the dispersed light intensity value. The measuring unit 551 may be a spectrophotometer that detects the tint by dispersing the reflected light for each wavelength by the diffraction grating 502.

(Measurement unit)
Next, the measurement unit 500 including the moving unit 575 as the moving means for moving the measuring unit 551 in the moving direction MD will be described with reference to FIG. FIG. 4 is an explanatory diagram of the measurement unit 500. The measuring unit 500 includes a measuring unit 551, position sensors 580 and 581, and a moving unit 575. The moving unit 575 includes a moving motor 570, a moving belt 571, a moving pulley 572, and a moving belt 573. The holding member 574 that holds the measuring unit 551 is attached to the moving belt 573. The moving belt 571 transmits the rotation of the moving motor 570 to the moving pulley 572. The rotation of the moving pulley 572 causes the moving belt 573 to rotate, whereby the measuring unit 551 moves in the front-back direction of the image forming apparatus 100, that is, in the moving direction MD.

The mobile motor 570 as a drive source for driving the measurement unit 551 is a stepping motor. The rotation amount and rotation speed of the mobile motor 570 are controlled by the control unit 560 (FIG. 5) provided in the adjustment unit 400. Thereby, the moving amount and the moving speed of the measuring unit 551 in the moving direction MD are controlled. The position sensors 580 and 581 are transmissive optical sensors. The position sensors 580 and 581 are arranged in an area where ordinary print paper on which an image is formed by the image forming apparatus 100 does not pass. The flag member 552 is provided so as to move in conjunction with the measuring unit 551. The position sensors 580 and 581 detect the flag member 552. The position sensors 580 and 581 are located in a standby position where the flag member 552 is detected by the position sensor 580 or 581 when the normal print paper is conveyed.

(Control unit)
Next, the control unit 560 that controls the measurement unit 500 will be described with reference to FIG. FIG. 5 is a block diagram of the control unit 560. The control unit 560 includes a CPU 561 and motor drive circuits 562, 563, and 564. The motor drive circuit 562 drives the mobile motor 570. The motor drive circuits 563 and 564 drive the transfer motors (conveyor units) 420 and 421, respectively. The CPU 561 controls the mobile motor 570, the transfer motors 420 and 421, the paper sensor 410, the measuring unit 551, and the position sensors 580 and 581 according to the program stored in the internal memory.

The CPU 561 controls the timing at which the transfer motors 420 and 421 are stopped based on the signal that the paper sensor 410 has detected the color chart. The CPU 561 controls turning on / off the white LED 501 of the measuring unit 551. The CPU 561 has a communication function for transmitting / receiving data to / from the measuring unit 551. The CPU 561 controls to stop the mobile motor 570 based on the detection signals of the position sensors 580 and 581. The CPU 561 of the control unit 560 can be electrically connected to the image forming apparatus 100. The CPU 561 receives the position information of the patch image 520 formed on the color chart from the image forming apparatus 100, and switches the rotation speed of the moving motor 570 based on the position information of the patch image 520. Although the present embodiment shows an example in which the CPU 561 is electrically connected to the image forming apparatus 100, an information device such as a personal computer is directly connected to the adjustment unit 400, and the CPU 561 receives a patch image 520 from the information device. It may be a system configuration that receives the location information of.

Next, the function of the CPU 561 that switches the speed of the mobile motor 570 based on the color chart information will be described with reference to FIGS. 6, 7, and 8. FIG. 6 is a diagram showing a normal printing paper 211 and a color chart 212. FIG. 6A is a diagram showing an example of ordinary print paper 211 in which a user forms an image on paper 110 by the image forming apparatus 100. FIG. 6B is a diagram showing a color chart 212 in which the patch image 520 is formed on the paper 110 by the image forming apparatus 100. Patch image 520 includes reference patches K1, K2, K3, K4, K5 and K6 and color patches P1, P2 and P3. In the image shown in FIG. 6A, it is the company logo "CANON" in the shaded areas A1, A2, and A3 that the user demands high color reproducibility and stability for the color, and in particular. , The part corresponding to the corporate color of the company. Therefore, as shown in FIG. 6B, the color chart 212 in which the color patches P1, P2, and P3 are limitedly formed in the areas corresponding to the areas A1, A2, and A3 requested by the user is periodically formed during the print job. Output to. Then, the color chart periodically output during the print job is measured by the adjustment unit 400, and the color value is measured.

The reference patches K1 to K6 are used as a reference trigger for determining the timing at which the color patches P1 to P3 are measured by the measuring unit 551. Even if the color chart 212 is transported with a slight deviation in the direction perpendicular to the transport direction CD, the positional relationship between the reference patches K1 to K6 and the color patches P1 to P3 is not affected. Therefore, by using the reference patches K1 to K6 as the reference trigger for determining the timing of the color measurement, the color patches P1 to P3 can be measured accurately.

FIG. 7 is a timing chart showing the speed switching of the measuring unit 551. The control unit 560 can switch the moving speed of the measuring unit 551 to at least two speeds. With respect to the color chart 212 shown in FIG. 6B, in the present embodiment, the control unit 560 switches the rotation speed of the moving motor 570 so that the moving speed of the measuring unit 551 can be switched as shown in FIG. .. When the movement of the measuring unit 551 is started in the moving direction MD, the control unit 560 controls the rotation speed of the moving motor 570 so that the moving speed of the measuring unit 551 becomes the first speed. In this embodiment, the first speed is set to 100 mm / s, but the first speed is not limited to this, and is 90 mm / s and 110 mm / s according to the performance and other conditions of the measuring unit 551. Other suitable speeds such as s may be set. The control unit 560 drives the measurement unit 551 at a moving speed of 100 mm / s until the measurement unit 551 detects the reference patch K1.

When the measuring unit 551 moves by the first predetermined distance from the time when the measuring unit 551 detects the reference patch K1, the control unit 560 accelerates the moving speed of the measuring unit 551 to the second speed. Control the rotation speed of. In this embodiment, the first predetermined distance is set to 2 mm, but the first predetermined distance is not limited to this. The determination of whether or not the measuring unit 551 has moved by the first predetermined distance is based on whether or not the moving motor 570 has rotated by a predetermined number of pulses (rotation amount) corresponding to the first predetermined distance. Judged. The second speed is faster than the first speed. In this embodiment, the second speed is set to 300 mm / s, but the second speed is not limited to this, and is 290 mm / s and 310 mm / s according to the performance and other conditions of the mobile motor 570. Other suitable speeds such as s may be set.

The control unit 560 controls the moving motor 570 so that the measuring unit 551 moves at 300 mm / s in the section where the color patch P1 is not formed, and the moving speed of the measuring unit 551 is 100 mm / s in front of the color patch P1. The moving motor 570 is decelerated so as to become. In this embodiment, the control unit 560 controls the rotation speed of the mobile motor 570 so that the measurement unit 551 becomes the first speed at a second predetermined distance in front of the color patch P1. In this embodiment, the second predetermined distance is set to 2 mm, but the second predetermined distance is not limited to this. The second predetermined distance may be the same as or different from the first predetermined distance.

The measuring unit 551 measures the color patch P1 while moving at a moving speed of 100 mm / s. When the position sensor 580 detects the flag member 552, the control unit 560 stops the measurement unit 551. In this way, the high-speed section (acceleration section) for accelerating the moving speed of the measuring unit 551 in the region where the color patch P1 is not formed and the moving speed of the measuring unit 551 for measuring (reading) the color patch P1 are determined. A measurement section (reading section) for one speed is provided. By changing the moving speed of the measuring unit 551 between the high-speed section and the measuring section, it is possible to shorten the time required for measuring the color value.

FIG. 8 is a diagram showing arrangement position information of reference patches K1 to K6 and color patches P1 to P3 on the color chart 212. The CPU 561 functions as an information acquisition means for acquiring the arrangement position information of the reference patches K1 to K6 and the color patches P1 to P3 on the color chart 212 from an external device such as an image forming apparatus 100 or a PC (information device). An external device such as an image forming apparatus 100 or a PC (information device) can create placement position information based on the color chart 212 and transmit it to the adjustment unit 400. The arrangement position information of the reference patches K1 to K6 and the color patches P1 to P3 in the transport direction CD of the color chart 212 is represented by the distances Y1, Y2 and Y3. The distance Y1 represents the distance from the tip 110a of the paper 110 to the reference patch K1. The distance Y2 represents the distance between the reference patch K1 and the reference patch K3. The distance Y3 represents the distance between the reference patch K3 and the reference patch K5.

The arrangement position information of the reference patches K1 to K6 and the color patches P1 to P3 in the moving direction MD is represented by the distances X1, X2, X3, X4, X5 and X6. The distance X1 represents the distance from the reference patch K1 to the color patch P1. The distance X2 represents the distance from the color patch P1 to the reference patch K2. The distance X3 represents the distance from the reference patch K3 to the color patch P2. The distance X4 represents the distance from the color patch P2 to the reference patch K4. The distance X5 represents the distance from the reference patch K5 to the color patch P3. The distance X6 represents the distance from the color patch P3 to the reference patch K6. The CPU 561 extracts a distance equal to or greater than a third predetermined distance from the distances X1 to X6. In this embodiment, the third predetermined distance is set to 50 mm, but the third predetermined distance is not limited to this. The third predetermined distance may be set to an appropriate value according to the specifications of the adjustment unit 400. The CPU 561 sets the extracted section as a high-speed section and switches the moving speed of the measuring unit 551.

(Color measurement operation)
Next, a color measurement operation in which the adjustment unit 400 measures the color chart 212 will be described with reference to FIG. FIG. 9 is a flow chart showing a color measurement operation. The CPU 561 executes a color measurement operation according to a program stored in a storage unit built in the CPU 561. The color measurement operation is periodically started, for example, before the start of the print job and / or after each printing of a predetermined number of sheets is completed during the print job. When the color measurement operation is started, the CPU 561 acquires the arrangement position information of the reference patches K1 to K6 and the color patches P1 to P3 on the color chart 212 as shown in FIG. 8 from the image forming apparatus 100 (S101). A distance equal to or greater than a third predetermined distance is extracted from the distance Xn in the moving direction MD in the arrangement position information (S102). The distance Xn represents the distance from the reference patch to the color patch, the distance from the color patch to the color patch, and the distance from the color patch to the reference patch in the moving direction MD. In this embodiment, the third predetermined distance is set to 50 mm, and the distances X1, X3, X4 and X6 are extracted. The CPU 561 sets a high-speed section as a change speed section based on the extraction result (S103). In this embodiment, in the high-speed section corresponding to the distances X1, X3, X4 and X6, the moving speed of the measuring unit 551 in the moving direction MD can be switched from the first speed of 100 mm / s to the second speed of 300 mm / s. Is set to.

The CPU 561 determines whether or not the paper sensor 410 has detected the tip 110a of the paper 110 of the color chart 212 (S104). When the paper sensor 410 does not detect the tip 110a of the paper 110 of the color chart 212 (NO in S104), the CPU 561 returns the process to S104. When the paper sensor 410 detects the tip 110a of the paper 110 of the color chart 212 (YES in S104), the CPU 561 stops the paper 110 of the color chart 212 based on the distance Yn in the transport direction CD in the arrangement position information. (S105). The distance Yn represents the distance from the tip 110a of the paper 110 of the color chart 212 to the reference patch and the distance between the reference patch and the reference patch in the transport direction CD. In step S105, first, the CPU 561 determines the stop position based on the distance Y1 in the transport direction CD, and controls the transport motors 420 and 421 to stop the transport of the color chart 212.

After the transfer of the color chart 212 is stopped, the CPU 561 starts driving the mobile motor 570 (S106). The CPU 561 controls switching of the rotation speed of the mobile motor 570 for each section set in step S104 (S107). As a result, the measurement unit 551 moves at a higher speed in the high-speed section in which the color patch P1 is not formed, so that the time for the color measurement operation is shortened. In the measurement section, the measurement unit 551 can move at a speed suitable for color measurement and measure the color chart 212 with high accuracy.

The CPU 561 determines whether or not the position sensor 580 is turned on (S108). When the position sensor 580 is not turned on (NO in S108), the CPU 561 returns the process to S107 and continues the movement of the measuring unit 551. When the position sensor 580 is turned on (YES in S108), the CPU 561 reverses the moving motor 570 and moves the measuring unit 551 in the direction opposite to the moving direction MD. When the position sensor 581 is turned on, the moving motor 570 is turned off (S109). The CPU 561 controls the transfer motors 420 and 421 to restart the transfer of the color chart 212. The CPU 561 determines whether or not all the color patches P1 to P3 have been measured (S110).

If all the color patches P1 to P3 have not been measured (NO in S110), the CPU 561 returns to S105 with n = n + 1. The CPU 561 stops the transfer of the paper 110 of the color chart 212 based on the next Yn, and repeats the steps S106 to S110. When the measurement of all the color patches P1 to P3 is completed (YES in S110), the CPU 561 ends the color measurement operation.

In the present embodiment, the CPU 561 switches the moving speed of the measuring unit 551 between the first speed and the second speed based on the arrangement position information, but the present embodiment is not limited to this. The CPU 561 may switch the moving speed of the measuring unit 551 to three or more speeds based on the arrangement position information.

According to this embodiment, the moving speed at which the measuring unit 551 for measuring the color of the patch image 520 formed on the color chart 212 moves with respect to the color chart 212 can be switched between the first speed and the second speed. it can. As a result, the time required for color measurement can be shortened and productivity can be improved.

212 ... Color chart 500 ... Measurement unit 520 ... Patch image 551 ... Measurement unit 561 ... CPU
575 ... Moving unit 420 ... Conveying motor 421 ... Conveying motor CD ... Conveying direction MD ... Moving direction

Claims (6)

A transport unit that transports the color chart on which the patch image is formed in the transport direction,
A measuring unit that measures the color of the patch image formed on the color chart, and
A moving unit that moves the measuring unit in a moving direction orthogonal to the transport direction along the surface of the color chart, and a moving unit.
A control unit that acquires placement position information of the patch image formed on the color chart from an external device, and
With
The measuring unit is characterized in that the moving speed of the measuring unit by the moving unit is switched between a first speed and a second speed faster than the first speed based on the arrangement position information. .. The measuring unit according to claim 1, wherein the control unit determines a stop position of the color chart by the transport unit based on the arrangement position information. The patch image includes a reference patch and a color patch.
The control unit determines the stop position of the color chart in the transport direction based on the arrangement position information of the reference patch.
The measuring unit according to claim 2, wherein the control unit controls the moving unit so that the measuring unit reads the color patch while moving at the first speed. The measuring unit according to claim 3, wherein the control unit controls the moving unit so that the measuring unit moves at the second speed in a section in which the color patch is not arranged. The measuring unit according to claim 3 or 4, wherein the measuring unit measures the density and / or color value of the color patch. An image forming part that forms an image on paper,
The measuring unit according to any one of claims 1 to 5.
With
The image forming unit is characterized in that a patch image for color measurement is formed on the paper to create a color chart, and the arrangement position information of the patch image formed on the color chart is transmitted to the measurement unit. Image forming device.

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