JP2011076010A - Image forming apparatus and color shift correction program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus which can make compatible the maintenance of image quality and the improvement of usability. <P>SOLUTION: The image forming apparatus includes: an image forming means (image forming section 501) for forming an image; a plurality of image holding means (photoreceptor drum 100K etc.) for holding images formed in respective colors; a detection means (color shift amount detection section 101) for detecting a color shift amount of each image; a storing means (color shift correction execution mode storing section 102) for storing a correction execution mode; a selecting means (color shift correction execution mode selecting section 103) for selecting any color shift correction execution mode based on the detection result of the color shift amount of each image; and a correction means (color shift correction means 104) for correcting the color shift of the image formed on each image retaining means based on the selected color shift correction execution mode. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image forming apparatus and a color misregistration correction program.

  2. Description of the Related Art Conventionally, image forming apparatuses such as color printers and multifunction peripherals have a problem that color misregistration occurs when colors are superimposed, and various techniques for correcting such color misregistration have been proposed.

  For example, Japanese Patent Laying-Open No. 2006-284773 discloses a technique for reducing the execution time of the color misregistration correction mode.

  More specifically, the number of output of the toner pattern at the time of the color misregistration correction process by the next misregistration correction unit is changed according to the amount of change in the misregistration of each color detected during the color misregistration correction process by the misregistration correction unit. is doing.

  For example, when the positional deviation fluctuation amount is smaller than a predetermined value, the number of output of the toner pattern from the next time is made smaller than the current value. Conversely, when the positional deviation fluctuation amount is larger than the predetermined value, the output number is increased. The execution time required for the color misregistration correction process is optimized.

  Japanese Patent Laid-Open No. 2007-102014 discloses a technique for changing the color misregistration correction interval.

  More specifically, the time until the next color misregistration correction is changed according to the amount of color misregistration variation detected during the color misregistration correction process. That is, if the amount of color misregistration is less than a certain value, the time until the next color misregistration correction is extended to optimize the color misregistration correction interval, and the time required for color misregistration correction is shortened.

JP 2006-284773 A Japanese Patent Laid-Open No. 2007-102014

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus and a color misregistration correction program capable of both maintaining image quality and improving convenience.

  In order to solve the above problems, an image forming apparatus according to a first aspect of the present invention is formed for each color by an image forming unit that forms an image composed of a plurality of colors based on image information, and the image forming unit. A plurality of image holding means for holding the respective images, a detecting means for detecting the amount of color misregistration of each image in each of the image holding means, and the frequency of performing the color misregistration correction of the images are set differently in a plurality of stages. A storage unit that stores a color misregistration correction mode; a selection unit that selects any one of the color misregistration correction modes from the storage unit based on a detection result of the color misregistration amount of each image by the detection unit; Correction means for correcting color misregistration of images formed on the image holding means by the image forming means based on the color misregistration correction embodiment selected by the selection means. And butterflies.

  According to a second aspect of the present invention, there is provided the image forming apparatus according to the first aspect, wherein the image forming unit forms a color matching adjustment pattern on the image holding unit for each color used for image formation, and the detection is performed. The means detects the amount of misregistration of each color matching adjustment pattern as the amount of color misregistration, and the correcting means corrects the formation position of each color matching adjustment pattern based on the color misregistration correction mode. It is characterized by.

  According to a third aspect of the present invention, there is provided an image forming apparatus according to the first or second aspect of the present invention, wherein the color misregistration correction mode includes “next color misregistration” for each image holding unit. At least three stages: “No correction is performed” (level 1), “Next color misregistration correction is unnecessary but correction can be performed” (level 2), “Next color misregistration correction is performed” (level 3) A mode having the following implementation frequency is set.

  According to a fourth aspect of the present invention, there is provided an image forming apparatus according to any one of the first to third aspects, wherein the next color misregistration correction by the correcting means is not performed according to the color misregistration correction embodiment. Is characterized by comprising control means for controlling the color misregistration correction embodiment selected next by the selection means so as to shift to a stage where color misregistration correction is performed more frequently.

  According to a fifth aspect of the present invention, in the image forming apparatus according to the fourth aspect of the present invention, the image forming apparatus includes a history acquisition unit that acquires a history of the color misregistration amount by the detection unit, and the control unit is the history acquisition unit. In consideration of the acquired history, the color misregistration correction mode selected next time by the selection unit is controlled to increase or decrease the number of stages to which the color misregistration correction is performed more frequently. .

  According to a sixth aspect of the present invention, there is provided an image forming apparatus according to the fifth aspect of the present invention, further comprising an initialization unit that initializes the history acquired by the history acquisition unit. The history is initialized when the number of executions of the color misregistration correction mode reaches a preset threshold value.

  According to a seventh aspect of the present invention, there is provided an image forming apparatus according to the fifth aspect of the present invention, further comprising an initialization unit that initializes the history acquired by the history acquisition unit. The history is initialized when the number of transitions from the color misregistration correction embodiment to another color misregistration correction embodiment reaches a preset threshold value.

  According to an eighth aspect of the present invention, there is provided a color misregistration correction program comprising: an image forming process for forming an image composed of a plurality of colors on a plurality of image holding units based on image information; and a color of each image in each of the image holding units A color misregistration correction mode in which the frequency of color misregistration correction of the image is set differently in a plurality of stages based on a detection process for detecting a misregistration amount and the detection result of the color misregistration amount of each image in the detection process. Based on the selection process of selecting any one of the color misregistration correction embodiments from the storage means storing the image and the selected color misregistration correction embodiment, the color misregistration of the image formed on each image holding unit is corrected. The correction process is executed by the calculation means.

  According to the present invention, the following effects can be obtained.

  That is, according to the first aspect of the present invention, there is provided an image forming apparatus that corrects image color misregistration based on the selected color misregistration correction mode and maintains both image quality and convenience. Can be provided.

  According to the second aspect of the present invention, the image forming apparatus that maintains the image quality and improves the convenience by correcting the formation position of each color matching adjustment pattern based on the selected color misregistration correction embodiment. Can be provided.

  According to the third aspect of the present invention, it is possible to provide an image forming apparatus that achieves both maintenance of image quality and improvement in convenience by setting an aspect having at least three stages of execution frequency.

  According to the fourth aspect of the present invention, it is possible to provide an image forming apparatus capable of both maintaining image quality and further improving convenience.

  According to the fifth aspect of the present invention, it is possible to provide an image forming apparatus capable of achieving both maintenance of image quality and further improvement of convenience in consideration of the history of color misregistration amount.

  According to the sixth aspect of the present invention, this image formation that initializes the history of the amount of color misregistration based on the number of executions of the color misregistration correction mode, and maintains both image quality and further convenience. An apparatus can be provided.

  According to the seventh aspect of the present invention, the history of the color misregistration amount is initialized based on the number of times of transition to another color misregistration correction embodiment, and both the maintenance of image quality and the further improvement of convenience are achieved. An image forming apparatus that can be used can be provided.

  According to the eighth aspect of the present invention, there is provided a color misregistration correction program that corrects color misregistration of an image based on a selected color misregistration correction mode and maintains both image quality and convenience. can do.

1 is a configuration diagram illustrating a schematic configuration example of an image forming apparatus PR1 according to an embodiment. 2 is a functional block diagram showing a functional configuration of an image forming apparatus PR1 according to an embodiment. FIG. It is explanatory drawing which shows the structural example regarding color shift correction. It is explanatory drawing which shows the example of the pattern for color matching adjustment. It is a flowchart which shows the process sequence of color misregistration correction execution processing. It is explanatory drawing which shows the example of creation of the pattern for color matching adjustment. It is a flowchart which shows the process sequence of a color shift level determination process. It is a flowchart which shows the process sequence of color misregistration correction implementation determination processing. It is explanatory drawing which shows the example of the implementation timing of color misregistration correction. It is explanatory drawing which shows the example of the implementation timing of the color misregistration correction as a comparison object. It is a flowchart which shows the other process sequence of a color shift level determination process. It is explanatory drawing which shows the example of the color misregistration correction implementation timing when the color misregistration amount gets worse than expected. It is explanatory drawing which shows the other example of the color misregistration correction implementation timing when the color misregistration amount gets worse than expected.

  Hereinafter, an embodiment as an example of the present invention will be described in detail with reference to the drawings. Here, in the accompanying drawings, the same reference numerals are given to the same members, and duplicate descriptions are omitted. In addition, since description here is the best form by which this invention is implemented, this invention is not limited to the said form.

  With reference to FIGS. 1 to 13, an image forming apparatus PR1 according to an embodiment of the present invention will be described.

  FIG. 1 shows a schematic configuration of a full-color printer as the image forming apparatus PR1 according to the present embodiment.

  The image forming apparatus PR1 extracts yellow (Y), magenta (M), cyan (C), and black (K) color image information from predetermined full-color image information, and a single color toner image of each color. And an image forming unit 501 (an example of an image forming unit) that forms a multicolor toner image by overlapping the plurality of single color toner images on a recording medium, and thereby forms a predetermined full color image.

  The image forming unit 501 includes four single-color toner image forming units 600K, 600Y, 600M, and 600C that form single-color toner images of respective colors, and a recording medium transport unit 502 that transports a recording medium P such as printing paper. The four single color toner image forming units 600K, 600Y, 600M, and 600C are arranged in a line, and a recording medium conveyance unit 502 is arranged so that the recording medium P can be conveyed along the arrangement.

  Each of the monochromatic toner image forming units 600K, 600Y, 600M, and 600C includes photosensitive drums 100K, 100Y, 100M, and 100C (an example of an image holding unit) that are rotatably arranged, and the photosensitive drums 100K, 100Y, and 100M. , 100C, a uniformly charged corotron 2 that charges it to a predetermined charging potential, and the photosensitive drums 100K, 100Y, 100M, and 100C are exposed in accordance with image information of each color to expose the photosensitive drum 100K. , 100Y, 100M, and 100C, a laser exposure device 3 that forms an electrostatic latent image, a toner that contains toner of the same color as the color of image information, and that develops the electrostatic latent image with the toner, Transfer corotron 5 for transferring the toner image to the recording medium P, photosensitive member cleaning means (not shown), and photosensitive drums 100K, 100Y, 10 M, and a photosensitive drum driving stepping motor 6 for rotating the 100C at a predetermined period.

  The laser exposure device 3 receives one polygon mirror 3a that is rotatably arranged, one laser diode 3b that emits light in response to a predetermined light emission control signal, and image information of each color, and at a predetermined timing, the laser exposure unit 3 A light emission control unit 3c that outputs a light emission control signal according to image information, a scanning start sensor 3d that detects the rotational phase of the polygon mirror 3a from the reflected light, and a polygon mirror that rotates the polygon mirror 3a at a predetermined cycle and phase. And a stepping motor 3e for driving, and the exposure light of the laser diode 3b is reflected by the polygon mirror 3a to expose the photosensitive drums 100K, 100Y, 100M, and 100C.

  The monochromatic toner image forming units 600K, 600Y, 600M, and 600C charge the photosensitive drums 100K, 100Y, 100M, and 100C with the uniformly charged corotron 2, and the laser exposure unit 3 performs exposure according to the image information of each color. Then, electrostatic latent images are formed on the photosensitive drums 100K, 100Y, 100M, and 100C, and the developing device 4 develops the electrostatic latent images, whereby each color of each color is formed on the photosensitive drums 100K, 100Y, 100M, and 100C. A monochromatic toner image is formed.

  Further, the recording medium transport unit 502 passes through a plurality of recording medium storage trays 24 that can store a large number of recording media P and all the transfer positions of the single color toner image forming units 600K, 600Y, 600M, and 600C. And a transfer belt 7 that is rotatably arranged, a transfer belt driving stepping motor 22 that rotationally drives the transfer belt 7, and a registration roll 9 that supplies the recording medium P to the transfer belt 7 at a predetermined timing. And a recording medium adsorber 10 that is disposed opposite to the transfer belt 7 and electrostatically adsorbs the recording medium P to the transfer belt 7, and is disposed opposite to the transfer belt 7 to remove the charge from the recording medium P. A recording medium peeling device 11 that peels from the transfer belt 7, a pair of fixing rollers 12 that heat and press the recording medium P, and a description that the image is fixed. A recording medium discharge tray (not shown) that accommodates the medium P, a pair of reversing rollers 25 that can rotate forward and reverse, and a paper P other than the paper as much as possible when a paper jam occurs are disposed inside the apparatus main body. And a purge tray 23 to be discharged.

  When the recording medium conveyance unit 502 forms an image on only one side of the recording medium P, the recording medium P stored in the recording medium storage tray 24 is transferred to the registration roll 9, the transfer belt 7, and the fixing roller 12. Are sequentially conveyed and discharged to a recording medium discharge tray. When the recording medium transport unit forms images on both sides of the recording medium P, the recording medium P discharged from the fixing roller 12 is reversed by the reversing roller 25 in the transport direction of the recording medium P. Then, the sheet is sequentially conveyed again by the registration roll 9, the transfer belt 7, and the fixing roller 12 and discharged to the recording medium discharge tray. When a paper jam occurs, the recording medium P is discharged to the purge tray 23 via the fixing roller 12 and the reverse roller 25.

  Reference numeral 700 denotes a control device 700 that controls the image forming apparatus PR1, stores various data, and the like.

  Further, the image forming unit 501 forms color matching adjustment patterns 800K, 800Y, 800M, and 800C (see FIGS. 3 and 4) at the end portions of the photosensitive drums 100K, 100Y, 100M, and 100C.

  In the present embodiment, a color composed of an optical sensor or the like that detects the amount of misregistration of the color matching adjustment patterns 800K, 800Y, 800M, and 800C transferred to the transfer belt 7 in the vicinity of the photosensitive drum 100C. A deviation amount detection unit 101 (an example of detection means) is provided.

  The color misregistration amount detection unit 101 may be provided with a density sensor 900 as shown in FIG.

  Further, the image forming apparatus PR1 is not limited to the above-described configuration, and may be a full-color printer configuration using a transfer drum instead of the transfer belt (see, for example, JP-A-2002-357940).

  Next, the functional configuration of the image forming apparatus PR1 will be described with reference to the functional block diagram of FIG.

  The image forming apparatus PR1 forms an image composed of a plurality of colors (four colors of YMCK in the present embodiment) based on image information, and has the above-described image forming unit 501 (an example of an image forming unit). And a plurality (four in this embodiment) of photosensitive drums 100K, 100Y, 100M, and 100C that respectively hold images (YMCK toner images in the present embodiment) formed by the image forming unit 501 for each color. Alternatively, a color shift amount detection unit 101 (detection) including a transfer belt 7 (an example of an image holding unit) and an optical sensor that detects the color shift amount of each image on each of the photosensitive drums 100K, 100Y, 100M, and 100C. An example of a unit) and a color misregistration correction mode (color misregistration correction execution pattern) in which the frequency of color misregistration correction of an image is set differently in a plurality of stages. Color misregistration based on the detection result of the color misregistration amount of each image by the color misregistration correction implementation storage unit 102 (an example of a storage unit) configured by a disk drive, a nonvolatile memory, and the like, and the color misregistration amount detection unit 101 Based on the correction mode selection unit 103 (an example of a selection unit) that selects any one of the color shift correction modes from the correction mode storage unit 102 and the color shift correction mode selected by the correction mode selection unit 103. A color misregistration correction unit 104 (an example of a correction unit) that corrects color misregistration of images formed on the respective photosensitive drums 100K, 100Y, 100M, and 100C by the image forming unit 501 and color misregistration correction according to the color misregistration correction mode. For a color that is not subjected to the next color misregistration correction by the misregistration correction unit 104, the color misregistration correction mode that is selected next time by the correction mode selecting unit 103 is executed as the color misregistration correction. Color misregistration amount history for acquiring a color misregistration amount history by a control unit 105 (an example of a control unit) configured by a microcomputer or the like that performs control so as to shift to a higher level, and a color misregistration amount detection unit 101 An acquisition unit 106 (an example of a history acquisition unit) and a history initialization unit 107 (an example of an initialization unit) that initializes the history acquired by the color misregistration amount history acquisition unit 106 under a predetermined condition. .

  The image forming unit 501 forms color matching adjustment patterns 800K, 800Y, 800M, and 800C (see FIGS. 3 and 4) on the photosensitive drums 100K, 100Y, 100M, and 100C for each color used for image formation. The color misregistration amount detection unit 101 detects the misregistration amount of each of the color matching adjustment patterns 800K, 800Y, 800M, and 800C as the color misregistration amount. The color misregistration correction unit 104 is based on the color misregistration correction mode. The formation positions of the respective color matching adjustment patterns 800K, 800Y, 800M, and 800C may be corrected.

  Further, in the color misregistration correction embodiment, “next color misregistration correction is not performed” (level 1) and “next color misregistration correction is not necessary for each of the photosensitive drums 100K, 100Y, 100M, and 100C. It is also possible to set a mode having at least three stages of execution frequency, “correction is possible” (level 2) and “next color misregistration correction” (level 3).

  In addition, according to the color misregistration correction mode, for the color that is not subjected to the next color misregistration correction by the color misregistration correction unit 104, the color misregistration correction mode selected next time by the correction mode selecting unit 103 is the color misregistration correction. Transition to the higher-frequency stage (for example, according to the above example, “next color misregistration correction is not performed” (level 1) → “next color misregistration correction is unnecessary but correction can be performed”) (Transition to (level 2)).

  In addition, the control unit 105 considers the history acquired by the color misregistration amount history acquisition unit 106, and the color misregistration correction mode selected next time by the correction mode selecting unit 103 is frequently executed. Control may be made so as to increase or decrease the number of stages to be shifted in the direction.

  That is, for example, the color misregistration level of a color that is not subjected to color misregistration correction is two levels from the previous color misregistration level when the previous color misregistration level is level 1 and there is a history of color misregistration deterioration in the past. In other cases, the color misregistration level may be set to be one level worse than the previous color misregistration level.

  Further, the history initialization unit 107 may perform history initialization when the number of executions of any of the color misregistration correction embodiments reaches a preset threshold value.

  Furthermore, the history initialization unit 107 performs history initialization when the number of transitions from any color misregistration correction embodiment to another color misregistration correction embodiment reaches a preset threshold value. May be.

  Note that “the next color misregistration correction is unnecessary but can be performed” (level 2) in the above-described color misregistration correction embodiment may be adapted to other color operations. That is, color misregistration correction may be performed simultaneously when other colors perform color misregistration correction, and may not be performed when other colors are not performed.

  Accordingly, while increasing the color misregistration correction interval of each color, the color misregistration correction is performed at the same time as much as possible, so that the frequency of color misregistration correction is reduced and the convenience is improved while maintaining the image quality.

  Next, a configuration example related to color misregistration correction will be described with reference to the block diagram of FIG.

  The color matching adjustment pattern forming unit 200 provided in the control unit 700 creates toner color matching adjustment patterns 800K, 800Y, 800M, and 800C on the photosensitive drums 100K, 100Y, 100M, and 100C.

  The color matching adjustment patterns 800K, 800Y, 800M, and 800C formed on the photosensitive drums 100K, 100Y, 100M, and 100C are detected by the density sensor 900.

  The analog signal from the density sensor 900 is digitized (binary) with respect to a certain threshold value. In the digitized signal, the color misregistration detection unit 101 measures the interval between the toner colors.

  Based on the measured data, the color misregistration correction unit 104 performs color misregistration correction for each toner color.

  As a judgment for performing color misregistration correction, when the temperature from the previous color misregistration correction is changed by a certain temperature (for example, 3 ° C.), or when the previous color misregistration correction is performed, the number of printed sheets is a certain threshold (for example, 200). Color misregistration correction may be performed when the number of sheets exceeds the number of sheets.

  FIG. 4 shows an example of a color matching adjustment pattern.

  By detecting these color matching adjustment patterns 800K, 800Y, 800M, and 800C with an optical sensor, an interval from 800K to 800Y (Dk_y), an interval from 800K to 800M (Dk_m), and an interval from 800K to 800C ( Dk_c) is measured.

  The calculation method of the color misregistration amount is not particularly limited, but a method of comparing measured data with a reference value (ΔDy = Dk_y−Dk_y (reference)) or a method of comparing with a half of an 800K interval (ΔDy = Dk_y). -(Dk_y + Dy_k) / 2).

  In FIG. 4, the first edge portions of the color matching adjustment patterns 800K, 800Y, 800M, and 800C are detected, but more accurate by detecting the end portion of the pattern or repeatedly forming a plurality of toner patterns. Alternatively, color misregistration correction may be performed.

  Next, a processing procedure of color misregistration correction execution processing executed by the image forming apparatus PR1 having the above configuration will be described.

  First, color misregistration correction execution determination processing is executed in step S10. Details of the processing procedure will be described later.

  In step S11, a color matching adjustment pattern forming process for forming a color matching adjustment pattern is executed.

  At this time, only the color adjustment pattern for the color determined to be subjected to the color misregistration correction from the result of the color misregistration correction execution determination process is created.

  For example, as shown in FIG. 6, in addition to black K, (A) when all three colors (Y, M, C) are created, (B) Y, M, C When any one of the two colors is created, (C) one of Y, M, and C is created.

  Next, in step S12, color misregistration detection processing is performed in which the density sensor reads the distance between the K color and each of the other colors for the color matching adjustment patterns 800K, 800Y, 800M, and 800C.

  Next, the process proceeds to step S13, and a color misregistration correction process for calculating a color misregistration amount and a color misregistration correction value is executed based on the detection result of the color misregistration detection process.

  Subsequently, in step S14, a color misregistration level determination process is executed.

  A color shift level (levels 1 to 3) is determined for each color based on the color shift amount measured by color matching.

In the present embodiment, the level classification is as follows.
Level 1: When the amount of color misregistration is very small → “Next color misregistration correction is not performed”
Level 2: When the amount of color misregistration is small → “Next color misregistration correction is unnecessary but can be executed”
Level 3: When the color misregistration amount is large → “Next color misregistration correction”

  The level is not limited to this, and three or more levels may be provided.

  Here, with reference to the flowchart of FIG. 7, the procedure of the subroutine of the color misregistration level determination process will be described.

  This process is a level 3 when the color misregistration amount is larger than the threshold th_level3, a level 2 when it is larger than the threshold th_level2, and a level 1 otherwise.

  First, in step S140, the target color is switched from Y → M → C, and the process proceeds to step S141.

  In step S141, it is determined whether or not a color matching adjustment pattern has been created this time. If “No”, the process proceeds to step S146.

  In step S146, the color shift level = the previous color shift level + 1 is set, and the process proceeds to step S145.

  On the other hand, if “Yes” is determined in step S141, the process proceeds to step S142.

  In step S142, it is determined whether or not the color misregistration amount> threshold th_level3. If “Yes”, the color misregistration level = level 3 and the process proceeds to step S145.

  If “No”, the process proceeds to step S143.

  In step S143, it is determined whether or not color misregistration amount> threshold th_level2, and if “Yes”, the color misregistration level = level 2 and the process proceeds to step S145.

  If “No”, the process proceeds to step S144, and the color misregistration level = level 1 and the process proceeds to step S145.

  In step S145, it is determined whether or not all colors have been completed. If “No”, the process returns to step S140. If “Yes”, the process ends and the process returns to the main process in FIG.

  Next, with reference to the flowchart of FIG. 8, a processing procedure of the subroutine of the color misregistration correction execution determination process described above will be described.

  In step S110, it is determined whether it is the timing for color misregistration correction. If “No”, the process waits, and if “Yes”, the process proceeds to step S111.

  In step S111, it is determined whether all the color misregistration levels are level 2 or less. If “No”, the process proceeds to step S113.

  In step S113, color misregistration correction is performed for the level 3 and level 2 colors, and the process returns to the main process in FIG.

  On the other hand, if “Yes” is determined in step S111, the process proceeds to step S112 to return to the main process in FIG. 5 without performing color misregistration correction.

  In this way, in this processing, when all three colors are level 1 or level 2, color misregistration correction is not performed, and when there is even one color level 3, color misregistration correction is performed for the colors of levels 2 and 3. The color misregistration correction is not performed for the level 1 color.

  Looking at each color, the level 1 color is not subjected to the next color shift correction, and the level 3 color is subjected to the next color matching.

  For the level 2 color, if there is another level 3 color, the color misregistration correction is performed, but if there is no level 3 color, the color misregistration correction is not performed.

  FIG. 9 shows the timing of color misregistration correction of the image forming apparatus PR1 according to this embodiment.

  FIG. 10 shows the timing of color misregistration correction in a conventional image forming apparatus as a comparison target.

  As shown in FIG. 9, in this embodiment, by giving freedom to perform color matching at level 2, it is easy to create a timing at which color matching is performed for each color and no color misregistration correction is performed for all colors. .

  As described above, according to the image forming apparatus PR1 according to the present embodiment, the maintenance of the image quality and the improvement of the convenience are compatible.

  Next, another processing procedure of the color misregistration level determination processing subroutine will be described with reference to the flowchart of FIG.

  The color misregistration level determination process shown in the flowchart of FIG. 7 is an effective means for aligning the timing of color misregistration correction for each color and reducing the frequency of performing color misregistration correction. In some cases, it may be desirable to increase the accuracy of the color misregistration amount.

  In the color misregistration level determination process shown in the flowchart of FIG. 7, when color misregistration correction is not performed at level 1, color misregistration correction may not be performed at most twice, but the color misregistration amount is worse than expected. Can not cope with.

  In the color misregistration level determination process shown in the flowchart of FIG. 11, the color misregistration level is determined from the history of past color misregistration deterioration to cope with deterioration more than expected.

  The level classification is as described above.

  First, in step S239, the target color is switched from Y → M → C, and the process proceeds to step S240.

  In step S240, it is determined whether or not a color matching adjustment pattern has been created this time. If “No”, the process proceeds to step S251.

  In step S251, it is determined whether or not “color misregistration deterioration history” is acquired at the previous level 1 and the color misregistration amount history acquisition unit 106. If “Yes”, the process proceeds to step S252, where The process shifts to step S248 with the shift level = the previous color shift level + 2.

  If “No” is determined in step S251, the process proceeds to step S253, where the color shift level = the previous color shift level + 1, and the process proceeds to step S248.

  On the other hand, if “Yes” is determined in step S240, the process proceeds to step S241.

  In step S241, it is determined whether or not the amount of color misregistration> threshold th_level3. If “Yes”, the process proceeds to step S243, and the process proceeds to step S246 with the color misregistration level = level 3.

  If “No”, the process proceeds to step S242.

  In step S242, it is determined whether or not the amount of color misregistration> threshold th_level2. If “Yes”, the process proceeds to step S244, and the process proceeds to step S246 with the color misregistration level = level 2.

  If “No”, the process proceeds to step S245, and the color shift level = level 1 is set, and the process proceeds to step S246.

  In step S246, color misregistration correction was performed at level 2 in the previous time, but it is determined whether or not it was level 3 this time. Then, the process proceeds to step S248.

  In the case of “No”, the process proceeds to step S247, where it is determined whether or not it is the current level 1 at the previous level 3, and in the case of “Yes”, the process proceeds to step S250 and “color misregistration” is determined. The “deterioration history” is reset (initialized), and the process proceeds to step S248.

  In step S248, it is determined whether or not all colors have been completed. If “No”, the process returns to step S239, and if “Yes”, the process ends and the process returns to the main process in FIG.

  Here, in the color misregistration level determination process shown in the flowchart of FIG. 7, the color that has not been subjected to the formation of the color matching adjustment pattern this time is unconditionally incremented by +1 to the previous level.

  On the other hand, in the color misregistration level determination process shown in the flowchart of FIG. 11, the increase amount is determined with reference to the past history of color misregistration deterioration.

  That is, in the past, if “the previous level 2 and the color misregistration correction was performed but then deteriorated to the next level 3”, it is predicted that the color misregistration may be worse than expected. Set “Slip worsening history”.

  If the previous level 1 and “color misregistration deterioration history” is set, the previous color misregistration level is set to +2 instead of +1.

  As a result, the color misregistration correction may not be performed twice at the maximum, so that the case where the color misregistration amount deteriorates more than expected can be dealt with.

  In other cases, the previous misregistration level is incremented by one as in the color misregistration level determination process shown in the flowchart of FIG.

  In addition, as a condition for resetting the “color misregistration deterioration history”, it is determined that the color misregistration is improved when the color misregistration correction is performed at the previous level 3 and becomes level 1, and the “color misregistration worsening” is performed. “History” is reset so that the color matching interval is not shortened.

  FIG. 12 shows an example of the color misregistration correction execution timing when the color misregistration amount deteriorates more than expected, and FIG. 13 shows another example of the color misregistration correction execution timing when the color misregistration amount worsens more than expected. Indicates.

  The color misregistration correction execution determination process is as shown in the flowchart of FIG.

  As described above, according to the image forming apparatus PR1 according to the present embodiment, while increasing the color misregistration correction interval, the color misregistration correction is performed at the same time as much as possible, the frequency of color misregistration correction is reduced, and the image quality is improved. Both maintenance and improved convenience are achieved.

  Although the invention made by the present inventor has been specifically described based on the embodiments, the embodiments disclosed herein are illustrative in all respects and are not limited to the disclosed technology. Should not be considered. That is, the technical scope of the present invention should not be construed restrictively based on the description in the above embodiment, but should be construed according to the description of the scope of claims. All modifications that fall within the scope of the claims and the equivalent technology are included.

  When using a program, it can be provided via a network or stored in a recording medium such as a CD-ROM.

  That is, the predetermined program including the image processing program is not limited to being recorded in a storage device such as a hard disk as a recording medium, and the predetermined program can be provided as follows.

  For example, a predetermined program may be stored in the ROM, and the CPU may load the predetermined program from the ROM to the main storage device and execute it.

  Further, the predetermined program may be stored and distributed in a computer-readable recording medium such as a DVD-ROM, CD-ROM, MO (magneto-optical disk), or flexible disk.

  Further, the image forming apparatus or the like is connected to a server apparatus or a host computer via a communication line (for example, the Internet), and after the predetermined program is downloaded from the server apparatus or the host computer, the predetermined program is executed. You may do it. In this case, examples of the download destination of the predetermined program include a memory such as a RAM and a storage device (recording medium) such as a hard disk.

  The image forming apparatus and the color misregistration correction program according to the present invention can be applied to a color printer, a multifunction machine, and the like.

PR1 Image forming apparatus 2 Uniform charging corotron 3 Laser exposure device 3a Polygon mirror 3b Laser diode 3c Light emission control unit 3d Scan start sensor 3e Polygon mirror driving stepping motor 4 Developer 5 Transfer corotron 6 Photoconductor drum driving stepping motor 7 Transfer Belt 9 Registration Roll 10 Recording Medium Adsorber 11 Recording Medium Stripper 12 Fixing Roller 22 Transfer Belt Drive Stepping Motor 23 Purge Tray 24 Recording Medium Storage Tray 25 Reverse Roller 100K, 100Y, 100M, 100C Photosensitive Drum 101 Unit 102 color misregistration correction implementation storage unit 103 color misregistration correction implementation selection unit 104 color misregistration correction unit 105 control unit 106 color misregistration amount history acquisition unit 107 history initialization unit 200 adjustment pattern forming unit 500 Processor 501 an image forming unit 502 recording medium conveying unit 600K, 600Y, 600M, 600C monochromatic toner image forming unit 700 controller 800K, 800Y, 800M, 800C color combined adjustment pattern 900 concentration sensor 901 temperature sensor P recording medium

Claims (8)

Image forming means for forming an image composed of a plurality of colors based on image information;
A plurality of image holding means for holding images formed for each color by the image forming means;
Detecting means for detecting a color misregistration amount of each image in each image holding means;
Storage means for storing a color misregistration correction mode in which the frequency of color misregistration correction of the image is set differently over a plurality of stages;
Selection means for selecting any one of the color misregistration correction embodiments from the storage means based on the detection result of the color misregistration amount of each image by the detection means;
Correcting means for correcting color misregistration of images formed on the image holding means by the image forming means based on the color misregistration correcting embodiment selected by the selecting means;
An image forming apparatus comprising: The image forming unit forms a color matching adjustment pattern on the image holding unit for each color used for image formation,
The detecting means detects the amount of color misregistration of each color matching adjustment pattern as the amount of color misregistration,
The image forming apparatus according to claim 1, wherein the correction unit corrects the formation position of each color matching adjustment pattern based on the color misregistration correction embodiment. In the color misregistration correction embodiment,
For each of the image holding means, “next color misregistration correction is not performed” (level 1), “next color misregistration correction is unnecessary, but correction can be performed” (level 2), “next color misregistration”. The image forming apparatus according to claim 1, wherein an aspect having an execution frequency of at least three stages of “perform correction” (level 3) is set.   According to the color misregistration correction mode, for the color that is not subjected to the next color misregistration correction by the correction unit, the color misregistration correction mode that is selected next by the selection unit is more frequently performed. The image forming apparatus according to claim 1, further comprising a control unit that performs control so as to shift to a stage. A history acquisition unit that acquires a history of the color misregistration amount by the detection unit;
The control means includes
In consideration of the history acquired by the history acquisition unit, the color misregistration correction embodiment selected next by the selection unit is controlled so as to increase or decrease the number of stages to which the color misregistration correction is performed more frequently. The image forming apparatus according to claim 4. Comprising initialization means for initializing the history acquired by the history acquisition means;
6. The image according to claim 5, wherein the initialization unit executes the initialization of the history when the number of executions of any one of the color misregistration correction embodiments reaches a preset threshold value. 6. Forming equipment. Comprising initialization means for initializing the history acquired by the history acquisition means;
The initialization means executes the history initialization when the number of transitions from any one of the color misregistration correction embodiments to another color misregistration correction embodiment reaches a preset threshold value. The image forming apparatus according to claim 5. An image forming process for forming an image composed of a plurality of colors on a plurality of image holding means based on image information;
A detection process for detecting a color shift amount of each image in each image holding means;
Based on the detection result of the color misregistration amount of each image in the detection process, any one of storage means storing color misregistration correction embodiments in which the color misregistration correction frequency of the image is set differently in a plurality of stages is stored. A selection process of selecting a color misregistration correction embodiment;
Based on the selected color misregistration correction embodiment, a correction process for correcting the color misregistration of the image formed in each image holding means;
A color misregistration correction program characterized by causing an arithmetic means to execute.

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