JP2005283898A - Image forming apparatus and method for color balance adjustment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus and a method for color balance adjustment accurately detecting density or chromaticity of a patch by reducing the influence of fluttering caused by transportation of transfer material when the density or the chromaticity of the color patch fixed on the transfer material is detected. <P>SOLUTION: Color patches of different colors are formed on the transfer material (S2) and reflected light intensity of the light irradiated on the transfer material, on which the color patch is formed, is detected. At this time, transporting speed of the transported transfer material is reduced (S6) and an image forming condition in an image forming part is set by detecting the chromaticity of the color patch on the basis of the reflected light intensity from the detected color patch in this state (7). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus such as a color printer and a color balance adjusting method thereof.

  In order to stabilize the color of a color image formed by an image forming apparatus such as a color laser beam printer, the density of the toner image before fixing on the paper as the transfer material, or the color of the toner image after fixing on the paper It is known to detect taste and feed back the detection result to image forming conditions to control image forming processing.

However, when such an image forming apparatus is used, if the characteristics of each part of the apparatus change due to changes in the installation environment of the apparatus or long-term use, the density and chromaticity of the formed image will change. . In particular, in the case of an electrophotographic color printer, there is a risk that the color balance may be lost even with a slight change in density. Therefore, it is necessary to always maintain a constant density and gradation in a recording unit for recording an image of each color. . Therefore, gradations such as a calibration table for correcting the density-gradation characteristics specific to the color image forming apparatus by setting several kinds of exposure conditions and development biases corresponding to the absolute humidity for each color toner are set. A correction means is provided, and based on the absolute humidity measured by the temperature and humidity sensor, process conditions and gradation correction values corresponding to the absolute humidity are selected. In addition, a toner image for density detection (hereinafter referred to as a toner patch or simply a toner image) is used so that a substantially constant density, gradation, and color can be obtained even if fluctuations occur in each part of the apparatus in use. Patch) is created on an intermediate transfer member, this is transferred to a transfer material such as recording paper, the density of the transferred toner patch is detected by an optical sensor, and the result is determined by process conditions such as exposure amount and development bias. Thus, the density control of the formed image is performed.
JP 2003-084532 A

  However, the above control method has the following problems.

  In order to obtain a stable image, patches of various chromaticities are formed on the transfer material, and these chromaticities are actually measured with an optical sensor to determine the difference from the desired chromaticity. It is necessary to provide feedback on the conditions. In addition, in order to measure a patch with a sensor with high accuracy, it is necessary to keep the distance between the sensor and the patch on the transfer material to be measured constant. For this reason, it is necessary to stably convey the transfer material while suppressing the fluctuation of the transfer material in the conveyance path of the part where the sensor is installed as compared with other conveyance paths.

  Furthermore, it is desirable to form a patch for measurement by a sensor under the same conditions as in a normal image forming operation. At this time, the number of patches that can be formed on the transfer material is limited by the transfer speed of the transfer material and the measurement time per patch by the sensor. However, in order to control the color stability of the image forming apparatus, it is desirable to form more patches, detect them, and feed back the measurement results to the image forming conditions.

  The present invention has been made in view of the above problems, and when detecting the density or chromaticity of a color patch fixed on a transfer material, the density and color of the patch can be reduced by reducing the influence of flutter associated with the transfer of the transfer material. Provided are an image forming apparatus for accurately detecting the degree and a color balance adjusting method thereof.

According to one aspect of the present invention, the image forming apparatus of the present invention has the following configuration. That is,
An image forming apparatus that forms an image by transferring a toner image to a transfer material,
Means for forming color patches of different colors on the transfer material;
A light detecting means for detecting a reflected light intensity of light irradiated on the transfer material on which the color patch is formed;
Conveying means for conveying the transfer material on which the color patch is formed;
Control means for controlling to reduce the transport speed of the transfer material transported by the transport means when detecting the reflected light intensity from the color patch by the light detection means,
The control unit sets an image forming condition in the image forming unit based on the reflected light intensity from the color patch detected by the light detection unit under the control of the control unit.

According to one aspect of the present invention, the image forming apparatus of the present invention has the following configuration. That is,
An image forming apparatus that forms an image by transferring a toner image to a transfer material,
Means for forming color patches of different colors on the transfer material;
A light detecting means for detecting a reflected light intensity of light irradiated on the transfer material on which the color patch is formed;
Conveying means for conveying the transfer material on which the color patch is formed;
Control means for controlling to stop the conveyance of the transfer material by the conveyance means when the reflected light intensity from the color patch is detected by the light detection means,
The control unit sets an image forming condition in the image forming unit based on the reflected light intensity from the color patch detected by the light detection unit under the control of the control unit.

According to one aspect of the present invention, the color balance adjustment method in the image forming apparatus of the present invention has the following configuration. That is,
A color balance adjustment method in an image forming apparatus for forming an image by transferring a toner image onto a transfer material,
Forming different color patches on the transfer material;
A light detection step of detecting a reflected light intensity of light irradiated on the transfer material on which the color patch is formed;
A conveying step of conveying the transfer material on which the color patch is formed;
A control step of controlling to reduce the transport speed of the transfer material transported in the transport step when detecting the reflected light intensity from the color patch in the light detection step,
An image forming condition in the image forming unit is set based on the reflected light intensity from the color patch detected under the control step.

According to one aspect of the present invention, the color balance adjustment method in the image forming apparatus of the present invention has the following configuration. That is,
A color balance adjustment method in an image forming apparatus for forming an image by transferring a toner image onto a transfer material,
Forming different color patches on the transfer material;
A light detection step of detecting a reflected light intensity of light irradiated on the transfer material on which the color patch is formed;
A conveying step of conveying the transfer material on which the color patch is formed;
A control step of stopping conveyance of the transfer material and setting image forming conditions in the image forming unit based on the reflected light intensity from the color patch detected in the light detection step;
It is characterized by having.

  According to the present invention, when detecting the density or chromaticity of a color patch fixed on a transfer material, it is possible to accurately detect the density and chromaticity of the patch by reducing the influence of fluttering associated with the transfer of the transfer material. There is.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[Embodiment 1]
FIG. 1 is a diagram illustrating a configuration of a main part of an image forming unit (recording unit) of a color laser beam printer which is an example of a color image forming apparatus according to an embodiment of the present invention.

  This color laser beam printer forms an electrostatic latent image on a photosensitive drum with laser light generated based on an image signal in an image forming unit, and develops the electrostatic latent image with toner to form a visible image. . Further, the visible image is transferred to a transfer material (hereinafter referred to as recording paper, but this transfer material is not limited to paper), and then the visible image transferred to the recording paper is fixed. It is fixed by the portion 13. The image forming unit includes photosensitive drums 5Y, 5M, 5C, and 5K, injection charging units 7Y, 7M, 7C, and 7K as primary charging units, developing units 8Y, 8M, 8C, 8K, toner cartridges 11Y, 11M, 11C, 11K, an intermediate transfer body 12, a paper feeding section, a transfer section, and a fixing section 13. Here, Y is a member for forming a yellow image, M is a member for forming a magenta image, C is a member for forming a cyan image, and K is a member for forming a black image.

  The photosensitive drums 5Y, 5M, 5C, and 5K are each formed by applying an organic optical transmission layer to the outer periphery of an aluminum cylinder, and are rotated by a driving force of a driving motor (not shown) being transmitted. This drive motor rotates each of the photosensitive drums 5Y, 5M, 5C, and 5K in the counterclockwise direction according to the image forming operation. Laser beams to the photosensitive drums 5Y, 5M, 5C, and 5K are sent from the scanner units 10Y, 10M, 10C, and 10K, and selectively expose the surfaces of the photosensitive drums 5Y, 5M, 5C, and 5K. Thus, an electrostatic latent image is sequentially formed on each drum.

  As a primary charging unit, a total of four injection chargers 7Y, 7M, and 7C are used to charge the photosensitive drums of yellow (Y), magenta (M), cyan (C), and black (K) for each station. 7K, and each injection charger is provided with sleeves 7YS, 7MS, 7CS, 7KS, respectively. Further, as a developing unit, in order to visualize the electrostatic latent image, four developing devices 8Y for developing yellow (Y), magenta (M), cyan (C), and black (K) for each station. 8M, 8C, 8K, and each developing device is provided with sleeves 8YS, 8MS, 8CS, 8CK. Each developing device is detachably attached to the apparatus main body.

  The intermediate transfer body 12 is an endless belt stretched around the driving roller 18a and the driven rollers 18b and 18c, and is in contact with the photosensitive drums 5Y, 5M, 5C, and 5K, and rotates clockwise when forming a color image. The color images are sequentially transferred by the action of the primary transfer rollers 6Y, 6M, 6C, and 6K for the respective colors.

  A recording paper 1 is accommodated in a paper feeding cassette 2 or a paper feeding tray 3 as a paper feeding means (paper feeding port), and this recording paper 1 is transported by a paper feed roller 4 and a transport roller 24. 25, and reaches the registration roller 23. This is detected by the pre-registration sensor 19. At the time of image formation, the pre-registration sensor 19 stops the conveyance of the recording paper 1 for a predetermined time in accordance with the timing when the color visible image on the intermediate transfer body 12 reaches the transfer region. The recording paper 1 is fed from the registration roller 23 to the transfer area, and the secondary transfer roller 9 comes into contact with the intermediate transfer member 12 to convey the recording paper 1 in a sandwiched manner. In this way, the color visible image on the intermediate transfer body 12 is superimposed and transferred onto the recording paper 1. The secondary transfer roller 9 is brought into contact with the intermediate transfer body 12 as shown by the solid line in FIG. 1 while transferring the color visible image on the intermediate transfer body 12 to the recording paper 1. It is separated at the position indicated by the dotted line.

  The cleaner container 21 cleans the intermediate transfer belt 12 with a built-in cleaning blade, and stores toner remaining on the intermediate transfer belt 12 without being secondarily transferred as waste toner. The fixing device 13 fixes the toner image on the recording paper 1 while conveying the recording paper 1. The fixing roller 14 heats the toner, and the pressure roller for pressing the recording paper 1 against the fixing roller 14. 15. The fixing roller 14 and the pressure roller 15 are formed in a hollow shape, and heaters 16 and 17 are incorporated therein, respectively.

  The paper discharge sensor 20 detects the conveyance state of the recording paper 1. When the recording paper 1 is present in the paper discharge sensor 20, its output is at a high level, and when it does not exist, it is at a low level. As a result, if the output value of the paper discharge sensor 20 does not become high level within a predetermined time after fixing, it is determined that the recording paper 1 is not normally conveyed and the image forming operation is interrupted. The recording paper 1 after toner fixing is conveyed by the paper discharge roller 26 and discharged to the paper discharge unit 27, and the image forming operation is completed.

  The color sensor 42 is arranged downstream of the fixing device 13 in the conveyance path 25 of the recording paper 1, and after the rear end of the recording paper 1 on which the color patch for chromaticity control is formed passes through the paper discharge sensor 20, The leading edge of the recording paper 1 reaches the vicinity of the detection portion of the color sensor 42. The detection unit of the color sensor 42 is directed to the image forming surface of the recording paper 1 and outputs a signal obtained by detecting the color of the color patch after fixing formed on the recording paper 1 through an RGB filter. doing.

  The chromaticity control according to the present embodiment is performed by the user's manual operation when the user desires to perform the control, or when a change in the environment is detected, or after the chromaticity control is executed. It may be automatically performed at a predetermined timing such as when the number of sheets reaches a preset number.

  2A and 2B are diagrams illustrating the configuration of the color sensor 42 according to the present embodiment.

  The color sensor 42 processes a signal detected by a light emitting element 51 such as an LED, a light receiving element 52 such as a photodiode or Cds, optical elements 53 and 55 used for coupling the light receiving and emitting elements, and the light receiving element 52. An IC circuit (not shown) and the like, and a holder (not shown) that accommodates these are provided. The optical element 55 includes a color filter such as RGB corresponding to the color of the color patch to be detected. In this case, a total of three light receiving elements 52 are required corresponding to each RGB color fill.

  2A shows a configuration for detecting both the regular reflection component and the irregular reflection component of the reflected light from the patch 54, and FIG. 5B shows the irregular reflection component without being affected by the specular reflection from the patch 54. Only the reflected light is detected.

  The light receiving element 52 detects the intensity of reflected light from the color patch 54 that has passed through the RGB filters. Based on the reflected light intensity for each color component, the respective densities of the R, G, and B components of the color patch can be obtained.

  FIG. 3 is a diagram showing an example of a color patch pattern for density or chromaticity control according to the present embodiment.

  The patch pattern 301 is formed continuously by changing the density or chromaticity of single, or mixed color patches of C, M, Y, and K. Here, each patch is formed with the same color and density, and a gap in which nothing is recorded is provided between the patches. This is because the boundary of each patch is detected by this gap (usually white in the case of recording paper).

  FIG. 4 is a block diagram showing a schematic configuration of the laser beam printer (color image forming apparatus) according to the present embodiment.

  A control unit 401 controls the operation of the entire color image forming apparatus. As shown in FIG. 1 described above, the printer engine 402 has a plurality of image forming stations, and records and fixes a color image on the recording paper 1. The transport motor 403 is a motor for rotationally driving the paper feed roller 4, the transport roller 24, the paper discharge roller 26, and the like.

  The color sensor 42 includes the light emitting element 51 and the light receiving sensor 52 as shown in FIG. 2 described above, and a voltage signal corresponding to the reflected light intensity detected by the light receiving sensor 52 is input to the control unit 401. The paper discharge sensor 20 detects the recording paper 1 discharged from the fixing device 13.

  The control unit 401 includes a CPU 410 such as a microprocessor, a ROM 411 that stores programs executed by the CPU 410, data, and the like, and a RAM 412 that is also used as a work area for storing various data during control operations by the CPU 410. doing. Also provided is an A / D converter 413 for inputting the voltage output from the light receiving element 52 and performing A / D conversion. The ROM 411 also stores pattern data for forming a color patch pattern as shown in FIG.

  FIG. 5 is a flowchart for explaining the process of detecting the color patch formation and its chromaticity in the color image forming apparatus according to the first embodiment of the present invention. A program for executing this process is stored in the ROM 411. It is executed under the control of the CPU 410.

  In the first embodiment, the recording paper 1 is conveyed at a normal conveyance speed until the recording paper 1 passes through the fixing device 13 after the patch is transferred to the recording paper 1 by the secondary transfer roller 9, and the color sensor. When the patch density is detected by 42, the conveyance speed of the recording paper 1 is set to a half speed (hereinafter referred to as half speed).

  When this control process is started, first, in step S 1, the paper feed roller 4 is driven to rotate to transfer the recording paper 1 to the transport path 25, and the recording paper 1 passes through the transport path 25 to be transferred to the secondary transfer roller 9. Transport to position. At this time, the color patch pattern data is read from the ROM 411 of the control unit 401, and a patch image is formed on the intermediate transfer belt 12 in the same manner as the normal color image forming operation (step S2). The color patch image thus formed on the intermediate transfer belt 12 is transferred by the secondary transfer roller 9 to the recording paper 1 conveyed through the conveyance path 25 in step S3. The recording paper 1 to which the color patch has been transferred in this manner is sent to the fixing device 13, and the color patch is fixed to the recording paper 1 (step S4). The recording paper 1 on which the patch has been transferred and fixed in this manner is conveyed toward the paper discharge unit 27 by the paper discharge roller 26.

  At this time, when the output value of the paper discharge sensor 20 located immediately after the fixing device 13 changes from a high level to a low level, it is determined that the trailing edge of the recording paper 1 has passed the position of the paper discharge sensor 20. (Step S5) The process proceeds to Step S6, and the rotation of the transport motor 403 is adjusted so that the rotation speed of the paper discharge roller 26, that is, the transport speed of the recording paper 1, becomes half speed in order to suppress the flutter of the recording paper 1. And the recording paper 1 is conveyed. Thus, when the recording paper 1 reaches the position of the color sensor 42 in step S7, detection of the chromaticity of the color patch transferred onto the recording paper 1 by the sensor 42 is started. Here, the chromaticity is detected by the number of patches on the recording paper 1 and when the chromaticity of all the patches is detected, the recording paper 1 is discharged to the paper discharge tray 27 by the rotation of the paper discharge roller 26 in step S8. To do.

  Thereafter, the detected color patch chromaticity information is fed back to the image forming conditions such as the exposure amount, the developing bias, and the look-up table (LUT) of each image forming station, thereby obtaining a stable color balance image. Can do.

  As described above, according to the first embodiment, when detecting the chromaticity of a color patch, the conveyance speed of the recording paper 1 is set to half speed, and the density of the color patch transferred to the recording paper 1 is set. By detecting, the influence of fluttering caused by the conveyance of the recording paper 1 can be reduced, and the accuracy of patch chromaticity detection by the sensor 42 can be improved.

[Embodiment 2]
In the first embodiment described above, fluttering of the recording paper 1 is reduced by setting the conveyance speed of the recording paper 1 to a half speed when the sensor 42 detects the chromaticity. On the other hand, in the second embodiment, in the color image forming apparatus, when the color patch on the recording paper 1 is detected by the sensor 42, the conveyance of the recording paper 1 by the paper discharge roller 26 is temporarily stopped to thereby stop the recording paper 1 A method for detecting chromaticity without eliminating the flicker will be described.

  FIG. 6 is a flowchart for explaining the process of detecting the color patch formation and its chromaticity in the color image forming apparatus according to the second embodiment of the present invention. A program for executing this process is stored in the ROM 411. It is executed under the control of the CPU 410. Note that the hardware configuration of the color image forming apparatus according to the second embodiment is the same as that of the first embodiment, and a description thereof will be omitted.

  The processes in steps S11 to S14 in FIG. 6 are the same as the processes in steps S1 to S4 in FIG.

  In step S15, the recording paper 1 is conveyed in the direction of the paper discharge unit 27 until the color sensor 42 detects a patch. When the sensor 42 detects the patch, in step S16, the rotation of the paper discharge roller 26 is stopped and the recording paper is detected. Stop the movement of 1. Thus, in step S17, the sensor 42 measures the reflected light intensity from the patch fixed on the recording paper 1 in a state where there is no fluttering of the recording paper 1, and detects the color.

  Next, in step S18, it is determined whether or not the detection of the chromaticity of all the color patches has been completed. If not, the process proceeds to step S19 to detect the chromaticity of the next patch. The motor 403 is driven to rotate and the recording paper 1 is conveyed by the paper discharge roller 26. Next, when the next color patch is detected by the sensor 42 in step S20, the process returns to step S16, and the conveyance of the recording paper 1 is stopped again. In step S17, the chromaticity of the color patch on the recording paper 1 is detected. In this way, when the above processing is repeated for the number of patches and the chromaticity detection processing for all the color patches on the recording paper 1 is completed, the process proceeds from step S18 to step S21, and the recording paper 1 is discharged to the paper discharge tray 27.

  Thereafter, as in the first embodiment, based on the detected chromaticity information of the color patch, the image forming conditions in the image forming station for each color are set, and this control process ends.

  As described above, according to the second embodiment, since the conveyance of the recording paper 1 is temporarily stopped when the color density of the patch is detected by the color sensor 42, the influence of the fluctuation of the recording paper 1 due to the conveyance is eliminated. Chromaticity detection can be performed. Thereby, the accuracy of chromaticity detection of each color patch can be improved.

[Embodiment 3]
In the third embodiment of the present invention, in the color image forming apparatus shown in FIG. 1, in order to prevent a decrease in detection accuracy due to chromaticity unevenness in the patch surface, as shown in FIG. A method for improving the patch density detection accuracy by detecting the density of the patch at a plurality of locations will be described.

  FIG. 8 is a diagram for explaining a state in which reflected light from the color patch according to the third embodiment is detected.

  Here, the reflected light intensity from three points (measurement points 1 to 3) of the patch 301a of the color patch formed on the recording paper 1 is obtained. Similarly, measurement points 1 to 3 are set for each of the other patches. Note that the number of these measurement points is not limited to three and may be plural.

  FIG. 7 is a flowchart for explaining the process of detecting the color patch formation and its chromaticity in the color image forming apparatus according to Embodiment 3 of the present invention. The program for executing this process is stored in the ROM 411. It is executed under the control of the CPU 410. Note that the hardware configuration of the color image forming apparatus according to the second embodiment is the same as that of the first embodiment, and a description thereof will be omitted.

  The processing in steps S31 to S34 in FIG. 7 is the same as the processing in steps S1 to S4 in FIG.

  In step S35, the recording paper 1 is conveyed in the direction of the paper discharge unit 27 until the color sensor 42 detects the patch. When the sensor 42 detects the patch, in step S36, the rotation of the paper discharge roller 26 is stopped and the recording paper is detected. Stop the movement of 1. In this way, the reflected light intensity from the patch fixed on the recording paper 1 is measured by the sensor 42 in a state where the recording paper 1 is not fluttered, and the color is detected. Next, in step S37, it is checked whether or not the output of the sensor 42 at a plurality of measurement points (three points in the example of FIG. 8) in the patch has been acquired. If not, the process proceeds to step S38, and a predetermined time or a predetermined time. After transporting the recording paper 1 by the distance and then stopping the recording paper 1 at the measurement point, the output of the sensor 42 is acquired in step S36. When the output of the sensor 42 at a plurality of measurement points on the patch is acquired in step S37, the process proceeds to step S39, where the average value is obtained, and the chromaticity of the patch is obtained based on the average value.

  Next, in step S40, it is checked whether or not the chromaticity of all the patches has been obtained. If not, the process proceeds to step S41 to detect the chromaticity of the next patch. The recording paper 1 is conveyed until the patch reaches a position that can be detected by the sensor 42. When the next color patch is detected, the conveyance of the recording paper 1 is stopped and the process proceeds to step S36, and the chromaticity of each patch is obtained based on the reflected light intensity from a plurality of points of the color patch in the same manner as described above.

  When the chromaticities of all the color patches formed on the recording paper 1 are thus obtained, the process proceeds from step S40 to step S42, and the recording paper 1 is discharged to the paper discharge tray 27. Thereafter, as in the first and second embodiments, the image forming conditions in each image forming station are set based on the chromaticity information detected by the color patch, and this chromaticity control is terminated.

  As described above, according to the third embodiment, similarly to the second embodiment, since the conveyance of the recording paper 1 is stopped when the sensor 42 detects a patch, the recording paper flutter due to the conveyance is eliminated. Can do. Furthermore, since the sensor 42 detects the color of a plurality of locations of each patch of the recording paper 1 and uses the average value as the chromaticity of the patch, the detection accuracy can be improved by removing the influence of the chromaticity unevenness of the patch. .

  In the third embodiment, the conveyance of the recording paper 1 is stopped at each measurement point. However, the present invention is not limited to this, and the conveyance of the recording paper 1 is performed as in the first embodiment. The speed may be reduced.

  As described above, according to this embodiment, when the density or chromaticity of a color patch after fixing is detected and image forming conditions are set in each image forming station, the recording paper on which the color patch is formed By detecting the density or chromaticity of the patch by reducing the conveyance speed of the printer or stopping the conveyance, the chromaticity of the color patch can be detected with high accuracy by eliminating the influence of the flutter associated with the conveyance of the recording paper. can do.

  In addition, it is possible to detect the chromaticity of the color patch with high accuracy by detecting the reflected light from a plurality of locations of each patch and detecting the density and chromaticity of the color patch based on the average value thereof. .

1 is a diagram illustrating a configuration of a main part of an image forming unit (recording unit) of a color laser beam printer which is an example of a color image forming apparatus according to an embodiment of the present invention. It is a figure explaining the structure of the color sensor which concerns on this Embodiment. It is a figure which shows an example of the color patch pattern for density or chromaticity control based on this Embodiment. 1 is a block diagram showing a schematic configuration of a laser beam printer (color image forming apparatus) according to an embodiment. 5 is a flowchart for explaining color patch formation and processing for detecting chromaticity in the color image forming apparatus according to Embodiment 1 of the present invention. 10 is a flowchart for explaining color patch formation and processing for detecting the chromaticity in the color image forming apparatus according to Embodiment 2 of the present invention. 10 is a flowchart for explaining color patch formation and processing for detecting the chromaticity in the color image forming apparatus according to Embodiment 3 of the present invention. It is a figure explaining the state which detects the reflected light from the color patch which concerns on this Embodiment 3. FIG.

Claims (8)

An image forming apparatus that forms an image by transferring a toner image to a transfer material,
Means for forming color patches of different colors on the transfer material;
A light detecting means for detecting a reflected light intensity of light irradiated on the transfer material on which the color patch is formed;
Conveying means for conveying the transfer material on which the color patch is formed;
Control means for controlling to reduce the transport speed of the transfer material transported by the transport means when detecting the reflected light intensity from the color patch by the light detection means,
An image forming apparatus, wherein the control unit sets an image forming condition in an image forming unit based on the intensity of reflected light from the color patch detected by the light detecting unit under the control of the control unit. . An image forming apparatus that forms an image by transferring a toner image to a transfer material,
Means for forming color patches of different colors on the transfer material;
A light detecting means for detecting a reflected light intensity of light irradiated on the transfer material on which the color patch is formed;
Conveying means for conveying the transfer material on which the color patch is formed;
Control means for controlling to stop the conveyance of the transfer material by the conveyance means when the reflected light intensity from the color patch is detected by the light detection means,
An image forming apparatus characterized in that the control unit sets an image forming condition in an image forming unit based on a reflected light intensity from the color patch detected by the light detecting unit under the control of the control unit. .   The control means further obtains reflected light intensity at a plurality of locations in each patch by the light detection means, and sets image forming conditions in the image forming unit based on an average value of reflected light intensity at the plurality of locations. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus.   4. The color patch according to claim 1, wherein the color patch includes a plurality of patches, and each patch is a single color or a mixed color and is formed of a plurality of patches whose density or chromaticity is changed. The image forming apparatus according to claim 1. A color balance adjustment method in an image forming apparatus for forming an image by transferring a toner image onto a transfer material,
Forming different color patches on the transfer material;
A light detection step of detecting a reflected light intensity of light irradiated on the transfer material on which the color patch is formed;
A conveying step of conveying the transfer material on which the color patch is formed;
A control step of controlling to reduce the transport speed of the transfer material transported in the transport step when detecting the reflected light intensity from the color patch in the light detection step,
A color balance adjustment method in an image forming apparatus, wherein image forming conditions in an image forming unit are set based on reflected light intensity from the color patch detected under the control step. A color balance adjustment method in an image forming apparatus for forming an image by transferring a toner image onto a transfer material,
Forming different color patches on the transfer material;
A light detection step of detecting a reflected light intensity of light irradiated on the transfer material on which the color patch is formed;
A conveying step of conveying the transfer material on which the color patch is formed;
A control step of stopping conveyance of the transfer material and setting image forming conditions in the image forming unit based on the reflected light intensity from the color patch detected in the light detection step;
A method for adjusting color balance in an image forming apparatus.   The control step further includes obtaining reflected light intensity at a plurality of locations in each patch, and setting image forming conditions in the image forming unit based on an average value of reflected light intensity at the plurality of locations. The color balance adjusting method according to claim 5 or 6.   8. The color patch according to claim 5, wherein the color patch includes a plurality of patches, and each patch is a single color or a mixed color and is formed of a plurality of patches whose density or chromaticity is changed. The color balance adjusting method according to any one of the above.

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