Image formation device, color correction method and color correction program

Abstract

To correct variation in color generated at the time of start-up.SOLUTION: An image formation device incudes: an image formation part 10 for forming images composed of a plurality of colors on a medium a plurality of times; a detection part for detecting color information of the plurality of medium images formed by the image formation part 10, using an image sensor 30; a color information correction part 22 for correcting the color information when the image is formed first by a primary approximate expression 41 or a logarithmic approximate expression 42, using a plurality of color information; and a color correction part 23 for correcting color of the image formation part 10, using corrected color information obtained by correcting the color information.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an image forming apparatus, a color correction method, and a color correction program, and more particularly to an image forming apparatus capable of color printing. [Background technology]

[0002] In order to print stably without causing large fluctuations in color tone from the start of printing, a technique is known in which a print image is read by a sensor, and correction control is performed on the electrophotographic process to stabilize the color tone. For example, in the technology described in Patent Document 1, color misregistration is calculated based on the deviation amounts ΔH and ΔV of the distances between the centers of gravity of the pattern images of each color in the main scanning direction and sub-scanning direction, and color misregistration is corrected based on the calculation results, thereby eliminating the relative positional deviation of the transfer positions of each toner image onto the intermediate transfer belt. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-15762 A (paragraph 0023) Summary of the Invention [Problem to be solved by the invention]

[0004] In the technology described in Patent Document 1, the deviation amount of the center of gravity distance in the main scanning direction of the pattern image of each color and the deviation amount of the center of gravity distance in the sub-scanning direction are measured. In other words, the density of each color is not adjusted. Therefore, even if the position of the toner image of each color is correct, the composite color may not be the target color. In order to suppress the effects of initial fluctuations, values ​​vary due to uneven density and measurement unevenness, so the target value is often the average value of several sheets. If initial fluctuations occur on those several sheets, the average value of several sheets will be affected by the fluctuations, and there is a risk that it will differ from the true value of the first page.

[0005] The present invention has been made in consideration of the above problems, and has an object to provide an image forming apparatus, a color correction method, and a color correction program capable of correcting color variations that occur at start-up. [Means for solving the problem]

[0006] The above-mentioned object of the present invention can be achieved by the following means.

[0007] (1) An image forming apparatus comprising: an image forming unit that forms an image consisting of multiple colors on a medium; a detection unit that detects color information of the medium image formed by the image forming unit; a color information correction unit that uses the color information to correct the color information when forming an image; and a color correction unit that performs color correction on the image forming unit using corrected color information obtained by correcting the color information.

[0008] (2) The image forming apparatus according to (1), wherein the color information correction unit calculates the corrected color information using a linear approximation formula.

[0009] (3) The image forming apparatus according to (1), wherein the color information correction unit calculates the corrected color information using a logarithmic approximation formula.

[0010] (4) An image forming apparatus as described in (2) or (3), wherein the image forming unit continuously forms the image multiple times, and the color information correction unit corrects the color information when the image was formed for the first time using the detected multiple pieces of color information.

[0011] (5) The image forming device described in (1) above, wherein the medium is composed of a test printing medium and a plurality of actual printing media, the detection unit detects the color information during image formation of the test printing medium, and the image forming unit forms images on the plurality of actual printing media under conditions for which color correction has been performed by the color correction unit.

[0012] (6) The image forming apparatus described in (1) further includes a variation judgment unit that judges the magnitude of variation in the multiple pieces of color information detected by the detection unit, and when the variation judgment unit judges that the variation is greater than a reference value, the color information correction unit calculates the corrected color information using a logarithmic approximation formula, and when the variation judgment unit judges that the variation is smaller, the color information correction unit calculates the corrected color information using a linear approximation formula.

[0013] (7) The image forming apparatus described in (5), wherein the variation judgment unit causes the detection unit to detect the color information in the latter half of a first consecutive image formation, and the image forming unit performs a second consecutive image formation after the first consecutive image formation under conditions in which color correction has been performed by the color correction unit.

[0014] (8) The image forming device described in (1) above, wherein the medium is composed of a test printing medium and a plurality of actual printing media, and the color information correction unit corrects the color information when an image is formed on the test printing medium.

[0015] (9) The image forming apparatus according to (8), wherein the color information correction unit corrects the color information using an approximation formula in which either an elapsed time or a moving distance of the medium is a variable.

[0016] (10) The image forming apparatus described in (8) above, wherein the color information correction unit averages first color correction information corrected using an approximation equation with elapsed time as a variable and second color correction information corrected using an approximation equation with travel distance as a variable, and the color correction unit performs color correction using the average color information averaged by the color information correction unit as the corrected color information.

[0017] (11) The image forming apparatus according to (4), wherein the color information correction unit, before calculating the corrected color information using a linear approximation formula or a logarithmic approximation formula, uses any one of the detected multiple color information or an average value of these as the corrected color information.

[0018] (12) The image forming apparatus according to (11), wherein the average color information is a weighted average value obtained by changing weights of the detected plurality of pieces of color information.

[0019] (13) A color correction method executed by a control unit of an image forming apparatus having an image forming unit that forms an image consisting of a plurality of colors on a medium and a detection unit that detects color information of the medium image formed by the image forming unit, the color correction method comprising: a color information correction step of correcting the color information when forming an image using the color information; and a color correction step of performing color correction of the image forming unit using corrected color information obtained by correcting the color information.

[0020] (14) A color correction program to be executed by a control unit of an image forming device having an image forming unit that forms an image consisting of multiple colors on a medium and a detection unit that detects color information of the medium image formed by the image forming unit, the color correction program executing a color information correction step that uses the color information to correct the color information when forming an image, and a color correction step that uses corrected color information obtained by correcting the color information to perform color correction on the image forming unit. Effect of the Invention

[0021] According to the present invention, it is possible to correct color variations that occur at start-up. [Brief description of the drawings]

[0022] [Figure 1] 1 is a configuration diagram of an image forming apparatus according to a first embodiment of the present invention. [Diagram 2] 5A to 5C are diagrams illustrating a method for correcting color variations in an image forming unit in the first embodiment of the present invention. [Diagram 3] FIG. 2 is a configuration diagram of an image forming unit included in the image forming apparatus. [Figure 4] 1 is a diagram showing an example of a captured image of a medium image formed by an image forming unit, the medium image being captured by an image sensor; [Diagram 5]2 is a flowchart illustrating a color correction method according to a first embodiment of the present invention. [Figure 6] 13A to 13C are diagrams illustrating a method for correcting color variations in an image forming unit in a second embodiment of the present invention. [Figure 7] 10 is a flowchart illustrating a color correction method according to a second embodiment of the present invention. [Figure 8] 11A and 11B are diagrams illustrating a method for correcting color variation in an image forming unit in a comparative example of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Note that each drawing is merely a schematic illustration to allow a sufficient understanding of the present invention. Therefore, the present invention is not limited to the illustrated examples. In addition, in each drawing, common components or similar components are given the same reference numerals, and duplicated explanations thereof will be omitted.

[0024] The image forming apparatus of the present invention includes an image forming unit that forms an image of multiple colors on a medium multiple times, a detection unit that detects color information of the multiple medium images formed by the image forming unit, a color information correction unit that corrects the color information when the image is formed for the first time using the multiple pieces of color information, and a color correction unit that performs color correction on the image forming unit using corrected color information obtained by correcting the color information. Here, the color information correction unit estimates the original initial color information when there is no variation in the image forming unit using a linear approximation formula or a logarithmic approximation formula.

[0025] (First embodiment) FIG. 1 is a diagram showing the configuration of an image forming apparatus according to a first embodiment of the present invention. The image forming apparatus 100 includes an image forming section 10, a control section 20, an image sensor 30, and a storage section 40. The image forming unit 10 is a hardware device that forms a multi-color image on a medium P (FIG. 3) such as paper sheets or CD-ROMs. The image forming unit 10 employs an intermediate transfer system in which a toner image intermediately transferred to an intermediate transfer belt 14 (FIG. 3) is transferred to the medium, but may employ a direct transfer system in which the toner image is directly transferred to the medium P. The image sensor 30 includes both an image sensor 31 that captures a color image of the toner image transferred to the intermediate transfer belt 14 (FIG. 3), and an image sensor 32 that captures a color image of the medium image transferred to the medium. The image forming unit 10 has a characteristic that the color varies for each image formation, and that the color of the medium image gradually changes as the number of image formations increases.

[0026] The control unit 20 is a CPU (Central Processing Unit) and, by executing a program, realizes the functions of a color information extraction unit 21, a color information correction unit 22, a color correction unit 23, a variation determination unit 24, and an image formation control unit 25. The color information extraction unit 21 is a functional unit that extracts color information of a specific area of ​​a captured image of a medium image or a toner image captured by an image sensor 30. Here, color is a concept that includes white and black, and for example, L * a * b * The color information is quantified in a color system, an XYZ color system, or the like. The color information is converted using RGB values ​​under the illumination of the image sensor 30. In this embodiment, the color information extraction unit 21 extracts color information from multiple captured images acquired by multiple image formations at startup. There is variation in the color information of the multiple captured images. The color information extraction unit 21 and the image sensor 30 are collectively referred to as the detection unit.

[0027] The color information correction unit 22 estimates the original color information without variation that should be obtained in the initial (first page) image formation, using the multiple pieces of color information extracted by the color information extraction unit 21. A linear approximation formula or a logarithmic approximation formula is used for this estimation.

[0028] 2 is a diagram for explaining a method for correcting color variations in an image forming unit in the first embodiment of the present invention. The horizontal axis represents the number of pages when an image is formed on a sheet of paper, and the vertical axis represents the lightness L as color information. * Below, the lightness L in the uniform color space is * I will explain about chromaticity a * ,b * The same explanation is given for the lightness L * Instead of chromaticity, brightness or density may be used. * ,b * Instead of the above, chromaticity coordinates may be used.

[0029] Lightness L obtained by image formation on the first page * The white circle a indicates the brightness L obtained on pages 1, 2, 3, 4, 5, and 6. * are indicated by white circles b, c, d, e, and f. Lightness L * increases monotonically as the number of pages increases, and gradually saturates. The dashed line is an approximation curve for the white circles a, b, c, d, e, and f, and the dashed lines show the upper and lower limits of the variation. When the color information of the third page is acquired, the color information correction unit 22 modifies the lightness L of the three white circles a, b, and c. * Using the above, the parameters of the linear approximation formula or logarithmic approximation formula are obtained, and the lightness L of the first page is calculated using the linear approximation formula or logarithmic approximation formula of these parameters. * The brightness L of this first page is estimated. * The color correction unit 23 (FIG. 1) corrects the image-forming parameters of the image forming unit 10 so that the estimated value (white circle g) becomes the target value (white circles h, i, j) for the fourth page and thereafter.

[0030] Returning to the explanation of Figure 1 (configuration diagram), The color correction unit 23 uses the corrected color information corrected by the color information correction unit 22 to change the conditions to be instructed to the image forming unit 10. As a result, color correction is performed for the next image formation.

[0031] The variation judgment unit 24 judges the magnitude of variation in the image forming unit 10. The color information extraction for the variation judgment is performed when the machine stabilizes in the latter half of the printing process or during printing other than the actual printing (for example, during test printing). In addition, the color information correction unit 22 corrects the color information using the logarithmic approximation formula 42 because prediction accuracy is important when the variation is larger than the reference value, and uses the linear approximation formula 41 when the variation is smaller than the reference value. During continuous printing, several hundred pages are printed per minute, so as long as the variation is small, it is better to calculate the color target value by linear approximation. This allows the correct color target value to be quickly fed back to the next printing. The image formation control unit 25 controls the image forming unit 10 based on the corrected imaging parameters.

[0032] A linear approximation formula 41 and a logarithmic approximation formula 42 are stored in the storage unit 40.

[0033] FIG. 3 is a configuration diagram of the image forming unit of the image forming apparatus. The image forming unit 10 mainly includes a photoconductor 11, a developing unit 12, a charger 13, an intermediate transfer belt 14, a secondary transfer roller 15, a fixing unit 16, and a cleaning mechanism 17. An image sensor 31 captures an image of the toner image transferred to the intermediate transfer belt 14. An image sensor 32 captures an image of the fixed medium image.

[0034] The photoconductor 11 is charged by the charger 13 and partially exposed to laser light to form an electrostatic latent image. The four color developers 12 (12Y, 12M, 12C, 12K) develop this electrostatic latent image to form a toner image on the photoconductor 11. The four color photoconductors 11 (11Y, 11M, 11C, 11K) transfer the toner images to the intermediate transfer belt 14. The intermediate transfer belt 14 sequentially transfers the four color toner images to the medium P held between the intermediate transfer belt 14 and a secondary transfer roller 15. The fixer 16 fixes the toner image transferred to the medium P by heating. The cleaning mechanism 17 removes any toner images remaining on the intermediate transfer belt 14.

[0035] FIG. 4 is a diagram showing an example of a captured image of the medium image formed by the image forming unit 10, captured by the image sensor 30. As shown in FIG. The medium image 200 is composed of a user's actual image 220 formed in the center of the medium P (FIG. 3), four-color rectangular correction patches 210 (Y correction patch 211, M correction patch 212, R correction patch 213, G correction patch 214) formed in the upper cutting margin 209a, and four different color rectangular correction patches 210 (C correction patch 215, K correction patch 216, B correction patch 217, PK correction patch 218) formed in the lower cutting margin 209b. Four registration marks are formed to identify the cutting margins 209a and 209b.

[0036] 5 is a flowchart for explaining the color correction method according to the first embodiment of the present invention. This flow starts when the power is turned on or when the device is reset. The image formation control unit 25 of the control unit 20 determines image creation parameters corresponding to the correction patch 210 (FIG. 4) (S1). After the process of S1, the image formation control unit 25 causes the image forming unit 10 to form an image on the medium P (S2). After the process of S2, the color information extraction unit 21 extracts color information of the medium image (particularly, the correction patch 210) acquired by the image sensor 30 (S3).

[0037] After the process of S3, the control unit 20 judges which page the image formation is for (S4). When the image formation is for the first or second page ("first and second pages" in S4), the color correction unit 23 does not correct the color information. In other words, the color correction unit 23 sets the color information correction value to the color information extracted for the first and second pages (S5). That is, when the image formation is for the first page, the color correction unit 23 sets the color information correction value to the color information for the first page (white circle a), and when the image formation is for the second page, the color information correction value to the color information for the second page (white circle b) (S5). When the image formation is for the third page ("third page" in S4), the color correction unit 23 estimates the color information for the first page using a linear expression or a logarithmic approximation expression (S6), and sets the color information correction value to the color information extracted for the third page (S7). That is, the color correction unit 23 estimates the original color information of the first page when there is no variation, using three pieces of color information: the color information of the first page (white circle a), the color information of the second page (white circle b), and the color information of the third page (white circle c) (S6). This estimated value is called the color information estimate value of the first page (white circle g). Then, the color correction unit 23 sets the color information extracted for the third page (white circle c) as the color information correction value (S7). Also, when the image formation is for the fourth page or later ("fourth page or later" in S4), the color correction unit 23 sets the color information correction value (white circles h, i, j) as the color information estimate value of the first page (white circle g) (S8).

[0038] After the processes of S5, S6, and S8, the color correction unit 23 performs color correction of the image forming unit 10 (S9), and the process returns to S1 to determine the image forming parameters for the next page.

[0039] As described above, according to the image forming apparatus 100 of this embodiment, the control unit 20 estimates the original color information (white circle g) of the first page when there is no variation, using the color information of the correction patches 210 (FIG. 4) of the first to third pages when forming the image of the third page (S6). Then, when forming the image of the fourth page and thereafter, the control unit 20 corrects the color information with the estimated color information value (white circle g) (S8). Then, the control unit 20 performs color correction of the image forming unit 10 using the corrected color information (S9).

[0040] Second embodiment In the above embodiment, color information is estimated on the third page of image formation, and the color information estimated value is used on the fourth page and thereafter, but different correction values ​​(tentative target values) can be set for the fourth and fifth pages.

[0041] 6 is a diagram for explaining a method for correcting color variations in an image forming unit in a second embodiment of the present invention. As in FIG. 2, the horizontal axis represents the number of pages when an image is formed on a sheet of paper, and the vertical axis represents the lightness L * Below, the lightness L in the uniform color space is * I will explain about chromaticity a * ,b * The same explanation is given for the lightness L * Instead of this, brightness or density may be used.

[0042] As in the above embodiment, the lightness L obtained on the first, second, third, fourth, fifth, and sixth pages * When the color information of the third page is acquired, the color information correction unit 22 corrects the color information of the three points (for example, the lightness L * ) to obtain the parameters of the linear approximation formula or logarithmic approximation formula, and then use the linear approximation formula or logarithmic approximation formula of this parameter to obtain the color information of the first page (for example, lightness L * ) is estimated.

[0043] Furthermore, when color information for the fourth page is acquired, color information correction unit 22 sets the color information acquired for the first page (white circle a) as a provisional target value (white circle k). Furthermore, when color information for the fifth page is acquired, color information correction unit 22 sets the average value of the color information acquired for the first page (white circle a) and the color information acquired for the second page (white circle b) as a provisional target value (white circle l). Color correction unit 23 corrects the imaging parameters of image forming unit 10 using these provisional target values ​​(white circles k, l).

[0044] When color information for the sixth page and subsequent pages is acquired, the color information correction unit 22 estimates the lightness L of the first page using the approximation formula. *is set as the color information correction value (white circle m). The color correction unit 23 (FIG. 1) corrects the imaging parameters of the image forming unit 10 so that the color information correction value (color information of the first page estimated using the approximation formula (white circle g)) becomes the target value (white circle m) for the sixth page and thereafter.

[0045] FIG. 7 is a flowchart illustrating a color correction method according to the second embodiment of the present invention. In the tentative target value setting (S10), the image forming control unit 25 (FIG. 1) of the control unit 20 determines the image forming parameters (S11) and forms an image on a medium (paper sheet) (S12). After the process of S12, the color information extraction unit 21 extracts color information (e.g., lightness L, * ) is extracted (S13).

[0046] After the process of S13, the control unit 20 determines whether the image formation is for the first, second, or third page, the fourth, fifth page, or the sixth page or later (S14). When the image formation is for the first, second, or third page ("first, second, or third page" in S14), the color information correction unit 22 sets the color information correction value (white circle k) to the color information of the first page (white circle a) (S16). When the image formation is for the fourth page ("fourth page" in S14), the color information correction unit 22 sets the color information correction value (white circle k) to the color information of the first page (white circle a) (S16). When the image formation is for the fifth page (S14: "fifth page"), the color information correction unit 22 sets the color information correction value (white circle l) to the value (color information for the first page (white circle a) + color information for the second page (white circle b)) / 2 (S17). When the image formation is for the sixth page or later (S14: "sixth page or later"), the color information correction unit 22 sets the color information correction value (white circle m) to a value (white circle m) obtained by estimating the color information for the first page (white circle g (FIG. 2, 6)) using a linear expression or a logarithmic approximation expression (S18). After the processes of S15, S16, S17, and S18, the color correction unit 23 performs color correction of the image forming unit 10 (S19), returns the process to S11, and determines the imaging parameters for the next page.

[0047] As described above, according to the image forming apparatus of this embodiment, the color information read on the first page is fed back to the fourth page, and the color information read on the first and second pages is fed back to the fifth page, and the color information is corrected using a tentative target value. Setting a tentative target value is useful when there is a time constraint before setting a color information correction value (white circle m) to a value obtained by estimating the color information on the first page (white circle g (FIGS. 2 and 6)) using a linear expression or a logarithmic approximation expression. In addition, the amount of change in the color information correction value when image formation shifts from the third page to the fourth page is smaller than that of the image forming apparatus 100 of the first embodiment.

[0048] (Comparative Example) In each of the above embodiments, the color information of pages 1 to 3 (white circles a, b, c) is used to estimate the original color information of the first page (white circle g) using a linear equation or a logarithmic approximation equation, and the estimated value is used as the color information correction value, but the color information correction value for pages 4 and beyond can also be the average value of the color information of pages 1 to 3 (white circles a, b, c).

[0049] FIG. 8 is a diagram for explaining a method for correcting color variation in an image forming unit in a comparative example of the present invention. As in the above-described embodiments, the horizontal axis represents the number of pages when an image is formed on a sheet of paper, and the vertical axis represents the lightness L * In addition, the brightness L obtained in the image formation of the first page is * The white circle a indicates the brightness L obtained on pages 1, 2, 3, 4, 5, and 6. * are indicated by white circles b, c, d, e, and f. Lightness L * increases monotonically as the number of pages increases, and gradually saturates. The dashed and dotted line is an approximation curve for the white circles a, b, c, d, e, and f, and the dashed lines show the upper and lower limits of the variation.

[0050] When the color information of the first to third pages is acquired, the color information correction unit 22 uses the acquired color information (white circles a, b, c). When the color information of the fourth page is acquired, the color information correction unit 22 uses the lightness L *The average value is calculated. This average value is set as the color information correction value of the fourth page (black circle k). Next, when the color information of the fourth page is acquired, the color information correction unit 22 calculates the lightness L of the three nearest points (white circles b, c, d). * The average value of the lightness L of the three nearest points (white circles c, d, e) is calculated. This average value is set as the color information correction value of the fifth page (black circle l). Next, when the color information of the fifth page is acquired, the color information correction unit 22 calculates the lightness L of the three nearest points (white circles c, d, e). * The average value of these three points is calculated. This average value is the color information correction value (black circle m) on page 6. The lightness L of these color information correction values ​​(the average value of the three points) * ) to the target value for the next page.

[0051] As described above, according to the image forming apparatus of this comparative example, the average value of the most recent three points is calculated, so that the lightness L * As the average value increases, the average value also increases. In other words, the difference ΔL between the average value as the target value and the color information estimated value of the original color information of the first page (white circle g (Figure 2.6)) when there is no variation * In contrast, the image forming apparatus 100 according to the above-described embodiment can estimate the color information of the first page (white circle g (FIG. 2, 6)) when there is no variation, so the difference ΔL * does not occur.

[0052] (Modification) The present invention is not limited to the above-described embodiments, and modifications can be made without departing from the spirit of the present invention. For example, the following modifications are possible. (a) In each of the above embodiments, the image forming apparatus 100 of the above embodiment performs regular printing using a regular printing medium from the first page, but before regular printing, a trial printing may be performed using a trial printing medium. Note that the trial printing medium and the regular printing medium may be the same type of medium.

[0053] (b) In each of the above embodiments, an approximation formula with the number of pages as a variable is used, but when performing test printing, the color information correction unit 22 (Fig. 1) can use the color information detected when performing test printing by using an approximation formula (linear approximation formula or logarithmic approximation formula) with either the elapsed time or the moving distance of the medium as a variable. Here, the elapsed time is the rotation time of the photoconductor 11 (Fig. 3), and the moving distance is the moving distance where the photoconductor 11 and the medium come into contact with each other as the photoconductor 11 rotates.

[0054] The color information correction unit 22 may calculate average color information by averaging the first color correction information corrected using an approximation formula with the elapsed time as a variable and the second color correction information corrected using an approximation formula with the moving distance as a variable. The color correction unit 23 then performs color correction using the average color information averaged by the color information correction unit 22 as corrected color information. Furthermore, the color information correction unit 22 may calculate a weighted average value by changing the weighting of each corrected color information when averaging the first color correction information and the second color correction information. This makes it possible to suppress erroneous correction.

[0055] (c) In the first and second embodiments, the color information correction values ​​for the first and second pages are set to the color information of each page, but the color information correction value for the second page can also be set to the average of the color information for the first and second pages. [Explanation of symbols]

[0056] 10 Image forming section 11 Photoreceptor 20 Control section 21 Color information extraction section 22 Color information correction section 23 Color Correction Section 24 Variation Judgment Section 30,31,32 Image sensor 40 Storage section 41 First-order approximation formula 42 Logarithmic Approximation 100 Image forming device 200 Media Images 209a, 209b Cutting margin 210 Correction Patch 220 User real images P medium

Claims

1. an image forming unit that forms an image made of multiple colors on a medium; a detection unit that detects color information of a medium image formed by the image forming unit; a color information correcting unit that corrects the color information when forming an image by using the color information; a color correction unit that performs color correction on the image forming unit using corrected color information obtained by correcting the color information; An image forming apparatus comprising:

2. The color information correction unit calculates the corrected color information using a linear approximation formula. The image forming apparatus according to claim 1 .

3. The color information correction unit calculates the corrected color information using a logarithmic approximation formula. The image forming apparatus according to claim 1 .

4. the image forming unit continuously forms the image multiple times, The color information correcting unit corrects the color information at the time of the first image formation using the detected plurality of pieces of color information.

4. The image forming apparatus according to claim 2, wherein the first and second electrodes are arranged in a first direction.

5. The medium is composed of a test print medium and a plurality of actual print media, The detection unit detects the color information during image formation on the test printing medium, The image forming unit forms images on the plurality of original printing media under the conditions for which the color correction was performed by the color correction unit. The image forming apparatus according to claim 1 .

6. a variation determination unit that determines the magnitude of variation in the plurality of pieces of color information detected by the detection unit, The color information correction unit calculates the corrected color information using a logarithmic approximation formula when the variation determination unit determines that the variation is larger than a reference value, and calculates the corrected color information using a linear approximation formula when the variation determination unit determines that the variation is smaller. The image forming apparatus according to claim 1 .

7. the variation determination unit causes the detection unit to detect the color information during a second half of a first continuous image formation; The image forming unit performs a second continuous image formation after the first continuous image formation under the condition in which the color correction is performed by the color correction unit.

7. The image forming apparatus according to claim 6.

8. The medium is composed of a test print medium and a plurality of actual print media, The color information correcting unit corrects the color information when an image is formed on the test printing medium. The image forming apparatus according to claim 1 .

9. The color information correction unit corrects the color information by using an approximation formula in which either the elapsed time or the moving distance of the medium is used as a variable. The image forming apparatus according to claim 8.

10. the color information correction unit averages the first color correction information corrected using an approximation equation with the elapsed time as a variable and the second color correction information corrected using an approximation equation with the travel distance as a variable; The color correction unit performs color correction using the average color information averaged by the color information correction unit as the corrected color information. The image forming apparatus according to claim 8.

11. The color information correction unit, before calculating the corrected color information using the linear approximation formula or the logarithmic approximation formula, sets any one of the detected plurality of pieces of color information or an average value thereof as the corrected color information. The image forming apparatus according to claim 4 .

12. The corrected color information is a weighted average value obtained by changing the weights of the detected color information. The image forming apparatus according to claim 11.

13. A color correction method executed by a control unit of an image forming apparatus including an image forming unit that forms an image of multiple colors on a medium, and a detection unit that detects color information of the medium image formed by the image forming unit, comprising: a color information correcting step of correcting the color information when forming an image by using the color information; and a color correction step of performing color correction of the image forming unit using corrected color information obtained by correcting the color information. Color correction method.

14. A color correction program to be executed by a control unit of an image forming apparatus including an image forming unit that forms an image of a plurality of colors on a medium, and a detection unit that detects color information of the medium image formed by the image forming unit, a color information correcting step of correcting the color information when forming an image by using the color information; and performing a color correction step of correcting the color of the image forming unit using corrected color information obtained by correcting the color information. Color correction program.

Images