Image forming apparatus and program

Abstract

To provide an image forming apparatus and a program that can reduce the time to adjust positional deviation compared with a case where all image forming sections included in a plurality of image forming units form pattern images to adjust positional deviation.SOLUTION: An image forming apparatus comprises: image forming units 30, 50 that have intermediate transfer belts 40, 60 to which toner images formed by a plurality of image forming sections 32, 52 are primarily transferred; and a conveyance belt 21 that conveys a sheet to a secondary transfer position where the toner images formed respectively on the intermediate transfer belts 40, 60 of the image forming units 30, 50 are secondarily transferred. In adjusting positional deviation of the toner images, a control section 80 uses a preset part of the plurality of image forming sections of the image forming units 30, 50, to primarily transfer the toner images onto the intermediate transfer belts 40, 60, and secondarily transfers the toner images primarily transferred onto the intermediate transfer belts 40, 60 onto the conveyance belt 21 to form pattern images BC.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus and a program. [Background technology]

[0002] Patent Document 1 discloses an image forming apparatus including a pattern image forming unit that forms pattern images for detecting color shift at multiple detection positions, a color shift amount detecting unit that detects the pattern images for detecting color shift and reads the amount of color shift from the relative positional relationship of the pattern images, and an image forming position adjusting unit that adjusts the forming position of each toner image based on the amount of color shift.Patent Document 2 discloses an image forming apparatus having multiple developing units including a common color developing unit that visualizes common color images and a specific color developing unit that visualizes specific color images, and at least the specific color developing unit that visualizes undetectable or defective specific color images is incorporated into a corresponding imaging engine together with other developing units that visualize detectable common color or specific color images. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-226553 [Patent Document 2] Japanese Patent Application Laid-Open No. 2004-325972 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, in order to expand the color gamut of images formed by image forming devices, images are formed using not only toners of the basic colors known as CMYK colors, but also toners of special colors other than CMYK colors. Such image forming devices may be configured to form toner images on paper using multiple image forming units, each equipped with multiple image forming sections that form toner images. In each image forming unit, the toner images formed by the multiple image forming sections are primarily transferred onto an intermediate transfer body, and the toner images on the intermediate transfer body are then secondarily transferred onto paper transported along a paper transport path.

[0005] Here, the intermediate transfer body onto which the toner image is primarily transferred, and the conveyor belt that conveys the paper onto which the toner image on the intermediate transfer body is secondarily transferred, may become misaligned in the image forming position due to expansion caused by temperature rise within the device, vibrations during operation of the device, etc. For this reason, a detection device is provided downstream of the secondary transfer position of the most downstream image forming unit, and the toner images on each intermediate transfer body are secondarily transferred onto the conveyor belt, and a pattern image for adjusting the misalignment is formed on the conveyor belt and read by the detection device, thereby adjusting the misalignment.

[0006] However, if pattern images are formed by all the image forming sections of each image forming unit and then read by the detection device, the number of pattern images increases, which increases the time required to adjust the misalignment.

[0007] The object of the present invention is to provide an image forming device and a program that can shorten the time required to adjust misalignment compared to when pattern images are formed using all image forming sections of multiple image forming units and the misalignment is adjusted. [Means for solving the problem]

[0008] An image forming apparatus according to a first aspect of the present invention comprises a plurality of image forming units, each having a plurality of image forming sections and an intermediate transfer body onto which toner images formed by the plurality of image forming sections are primarily transferred; a conveying belt that conveys paper to a secondary transfer position where the toner images formed on the intermediate transfer bodies of the plurality of image forming units are secondarily transferred; a detection device that is disposed downstream of the plurality of secondary transfer positions in the conveying direction in which the paper is conveyed by the conveying belt and that detects a pattern image formed by the toner images secondarily transferred onto the conveying belt; and a processor. When adjusting the positional misalignment of the toner image, the processor primarily transfers the toner image onto the intermediate transfer body using a predetermined portion of the plurality of image forming sections of each of the plurality of image forming units, and secondarily transfers the toner image primarily transferred onto the intermediate transfer body onto the conveying belt to form the pattern image.

[0009] An image forming apparatus of a second aspect of the present invention is the image forming apparatus of the first aspect, wherein the processor adjusts the positional misalignment of toner images formed by each of the multiple image forming units for each of the multiple image forming units based on the detection results of the detection device.

[0010] An image forming apparatus of a third aspect of the present invention is the image forming apparatus of the first aspect, wherein the processor adjusts the positional misalignment of toner images formed by all image forming sections of the multiple image forming units based on the detection results of the detection device.

[0011] An image forming apparatus of a fourth aspect of the present invention is the image forming apparatus of the third aspect, wherein the plurality of image forming units include a first image forming unit and a second image forming unit, and when the misalignment of the pattern images formed by the predetermined first image forming section of the first image forming unit and the predetermined second image forming section of the second image forming unit detected by the detection device is below a predetermined threshold, the processor adjusts the positional misalignment of the toner images formed by all of the image forming sections of the first image forming unit and the second image forming unit based on the formed pattern images.

[0012] An image forming apparatus of a fifth aspect of the present invention is the image forming apparatus of the fourth aspect, wherein, when the misalignment of the pattern image detected by the detection device is greater than a preset threshold, the processor forms a new pattern image on the conveying belt by all image forming sections of the first image forming unit and the second image forming unit, and adjusts the positional misalignment of the toner images formed by all image forming sections of the first image forming unit and the second image forming unit based on the newly formed pattern image.

[0013] An image forming apparatus of a sixth aspect of the present invention is the image forming apparatus of the first aspect, wherein the processor forms a pattern image on the conveying belt using all image forming sections of the multiple image forming units when the status of the apparatus meets predetermined conditions.

[0014] An image forming apparatus of a seventh aspect of the present invention is the image forming apparatus of the sixth aspect, wherein the processor forms a pattern image on the conveying belt using all image forming sections of the multiple image forming units when the temperature change within the apparatus exceeds a predetermined range.

[0015] In an eighth aspect of the image forming apparatus of the present invention, in the image forming apparatus of the first aspect, the image forming section used when adjusting the positional misalignment of a toner image is the image forming section in each of the image forming units that is closest to the secondary transfer position.

[0016] In a ninth aspect of the image forming apparatus of the present invention, in the image forming apparatus of the first aspect, the image forming section used when adjusting the positional misalignment of a toner image is the image forming section of the color with the lowest reflectance in each of the image forming units.

[0017] A tenth aspect of the program of the present invention causes a computer to execute the following steps when adjusting the positional misalignment of a toner image: a step of primarily transferring a toner image onto an intermediate transfer body using a predetermined portion of a plurality of image forming sections of each of a plurality of image forming units, the image forming sections each having a plurality of image forming sections and an intermediate transfer body onto which the toner images formed by the plurality of image forming sections are primarily transferred; a step of secondarily transferring the toner image primarily transferred onto the intermediate transfer body onto a conveyor belt that conveys paper to a secondary transfer position, thereby forming a pattern image; and a step of detecting the pattern image by a detection device. [Effects of the Invention]

[0018] According to the image forming apparatus of the first aspect of the present invention, the time required to adjust misalignment can be shortened compared to when pattern images are formed by all image forming sections of multiple image forming units and the misalignment is adjusted.

[0019] According to the image forming apparatus of the second aspect of the present invention, the time required to adjust misalignment can be shortened compared to when pattern images are formed by all image forming sections of multiple image forming units and the misalignment is adjusted.

[0020] According to the image forming apparatus of the third aspect of the present invention, the time required to adjust misalignment can be shortened compared to when pattern images are formed by all image forming sections of a plurality of image forming units and the misalignment is adjusted.

[0021] According to the image forming apparatus of the fourth aspect of the present invention, the time required to adjust misalignment can be shortened compared to when misalignment is adjusted using pattern images formed by all image forming units.

[0022] According to the image forming apparatus of the fifth aspect of the present invention, it is possible to improve the accuracy of misregistration adjustment compared to when misregistration is adjusted using pattern images formed by two image forming units.

[0023] According to the image forming apparatus of the sixth aspect of the present invention, it is possible to improve the accuracy of adjusting misalignment in a situation where misalignment is likely to occur in the image forming position.

[0024] According to the image forming apparatus of the seventh aspect of the present invention, it is possible to improve the accuracy of adjusting misregistration in a situation where a temperature rise inside the apparatus easily causes a misregistration in the image forming position.

[0025] According to the image forming apparatus of the eighth aspect of the present invention, it is possible to reduce the influence of the intermediate transfer body and improve the accuracy of adjusting misregistration.

[0026] According to the image forming apparatus of the ninth aspect of the present invention, it is possible to improve the accuracy of adjusting misregistration compared to when an image forming unit of a color with high reflectance is used.

[0027] According to the program of the 10th aspect of the present invention, the time required to adjust misalignment can be shortened compared to when pattern images are formed by all image forming sections of a plurality of image forming units and the misalignment is adjusted. [Brief explanation of the drawings]

[0028] [Figure 1] 1 is a schematic diagram illustrating a configuration of an image forming apparatus according to an embodiment of the present invention. [Figure 2] FIG. 2 is a schematic diagram illustrating a configuration of an image forming unit according to an embodiment of the present invention. [Figure 3] 2 is a block diagram showing a control configuration of the image forming apparatus according to the embodiment of the present invention; FIG. [Figure 4] 10 is a flowchart illustrating an example of a process for adjusting misregistration in an image forming apparatus according to an embodiment of the present invention. [Figure 5] 10A and 10B are diagrams for explaining a pattern image used in the process of adjusting misregistration in the image forming apparatus according to the embodiment of the present invention. [Figure 6] 10A and 10B are diagrams for explaining a process for adjusting misregistration in an image forming apparatus according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0029] Next, an embodiment of the present invention will be described in detail with reference to the drawings.

[0030] [Image forming equipment] FIG. 1 is a diagram showing the configuration of an image forming apparatus 10 according to an embodiment of the present invention.

[0031] 1, image forming apparatus 10 includes a storage section 12 for storing paper PP, a transport section 11 for transporting paper PP along a transport path 19, and image forming units 30 and 50 for forming toner images to be transferred onto paper PP. Image forming unit 30 is used as a first image forming unit. Image forming unit 50 is used as a second image forming unit.

[0032] The storage section 12 can be pulled out from the image forming apparatus main body 10A, which is the main body of the image forming apparatus 10, and stores paper PP.

[0033] The conveying section 11 includes, in order from the upstream side in the conveying direction, a delivery roll 13, a conveying roll 14, a pair of registration rolls 15, a conveying belt device 20, a fixing device 18, and a discharge roll 17.

[0034] The delivery roll 13 delivers the paper sheet PP stored in the storage section 12 to a transport path 19 that constitutes the transport section 11. The transport roll 14 transports the paper sheet PP along the transport path 19.

[0035] The pair of registration rolls 15 transports the sheet PP transported by the transport rolls 14 to a secondary transfer position TJ2 on the downstream side, which will be described later. The pair of registration rolls 15 sandwiches the sheet PP between a registration roll 15A and a pinch roll 15B, and transports the sheet PP downstream in the transport direction.

[0036] The conveyor belt device 20 transfers the toner images formed by the image forming units 30 and 50 onto the paper PP, while conveying the paper PP downstream in the conveying direction along the conveying path 19. Details of the conveyor belt device 20 will be described later.

[0037] The fixing device 18 has a pair of fixing rolls 16, and heats and presses the paper PP onto which the toner image has been transferred as it passes between the pair of fixing rolls 16, thereby fixing the toner image to the paper PP.

[0038] The discharge rollers 17 discharge the paper PP onto which the toner image has been fixed by the fixing device 18 to the discharge section 9.

[0039] The image forming unit 30 and the image forming unit 50 are arranged side by side in the vertical direction. In this embodiment, the image forming unit 50 is arranged above the image forming unit 30. From another perspective, the image forming unit 50 is arranged downstream of the image forming unit 30 in the paper transport direction.

[0040] The image forming unit 30 forms toner images in special colors other than the basic colors of, for example, yellow, magenta, cyan, and black. The image forming unit 30 includes four image forming sections 32 and an intermediate transfer belt 40 as an intermediate transfer body onto which the toner images formed by the four image forming sections 32 are primarily transferred. The intermediate transfer belt 40 is endless, onto which the toner images formed by the four image forming sections 32 are transferred, and is mounted so as to be rotatable counterclockwise when viewed from the front in FIG. 1.

[0041] The image forming unit 32 includes an image forming unit 32P that forms a fluorescent pink toner image, an image forming unit 32S that forms a silver toner image, an image forming unit 32G that forms a gold toner image, and an image forming unit 32Gr that forms a fluorescent green toner image. These four image forming units 32 are arranged in the following order from the upstream side in the rotation direction of the intermediate transfer belt 40 (the side closest to the support roll 44, described later): image forming unit 32P, image forming unit 32S, image forming unit 32G, and image forming unit 32Gr. Hereinafter, the upstream side in the rotation direction of the intermediate transfer belt 40 will be referred to as the "upstream side in the rotation direction," and the downstream side in the rotation direction will be referred to as the "downstream side in the rotation direction." In other words, within the image forming unit 32, the image forming unit 32Gr is arranged furthest downstream in the rotation direction. Furthermore, within the image forming unit 32, the image forming unit 32Gr is arranged in a position closest to the secondary transfer position TJ2.

[0042] In addition, when there is no need to distinguish between P, S, G, and Gr, they will be omitted.

[0043] 2, the image forming unit 32 includes a photoconductor 33, a charging member 34 that charges the surface of the photoconductor 33, an exposure device 35 that irradiates the charged photoconductor 33 with light, and a developing device 36 that develops the electrostatic latent image formed by the exposure light and visualizes it as a toner image. The developing device 36 has a developing roll 39, and a developing bias is applied to it.

[0044] Furthermore, primary transfer rolls 37P, 37S, 37G, and 37Gr are disposed opposite the photoconductors 33 with the intermediate transfer belt 40 interposed therebetween, and transfer the toner images formed by the image forming unit 32 onto the intermediate transfer belt 40. The intermediate transfer belt 40 is wound around a support roll 44 that supports the intermediate transfer belt 40 and a backup roll 42 that is disposed in a secondary transfer unit 74 on the upstream side, which will be described later. The photoconductors 33, the primary transfer rolls 37, and the intermediate transfer belt 40 form a primary transfer unit 70. The positions between the photoconductors 33P, 33S, 33G, and 33Gr and the intermediate transfer belt 40 are designated as primary transfer positions TP1, TS1, TG1, and TGr1, respectively.

[0045] The image forming unit 50 has the same configuration as the image forming unit 30 except for the colors of the images it forms. The image forming unit 50 forms toner images of the basic colors, for example, yellow, magenta, cyan, and black.

[0046] The image forming unit 50 includes four image forming sections 52 and an intermediate transfer belt 60. The intermediate transfer belt 60 has toner images formed by the four image forming sections 52 transferred thereto and is mounted so as to be rotatable counterclockwise when viewed from the front in FIG.

[0047] 2, the image forming section 52 has the same configuration as the image forming section 32 of the image forming unit 30 except for the color of the image formed. The intermediate transfer belt 60 and the primary transfer roll 57, which will be described later, also have the same configuration as the intermediate transfer belt 40 and the primary transfer roll 37 of the image forming unit 30. The other components of the image forming unit 50 are also the same as those of the image forming unit 30.

[0048] The image forming unit 52 includes an image forming unit 52Y that forms a yellow toner image, an image forming unit 52M that forms a magenta toner image, an image forming unit 52C that forms a cyan toner image, and an image forming unit 52K that forms a black toner image. The four image forming units 52 are arranged in the following order from the upstream side in the rotation direction (the side closest to the support roll 64, described later): image forming unit 52Y, image forming unit 52M, image forming unit 52C, and image forming unit 52K. In other words, of the image forming units 52, the image forming unit 52K is arranged furthest downstream in the rotation direction. Furthermore, of the image forming units 52, the image forming unit 52K is arranged in a position closest to the secondary transfer position TK2.

[0049] It should be noted that when there is no need to distinguish between Y, M, C, and K, they will be omitted.

[0050] The image forming section 52 includes a photoreceptor 53, a charging member 54, an exposure device 55, and a developing device 56. The developing device 56 has a developing roll 59, and a developing bias is applied to it.

[0051] Additionally, primary transfer rolls 57Y, 57M, 57C, and 57K are disposed at positions facing each photoconductor 53 with the intermediate transfer belt 60 interposed therebetween. The intermediate transfer belt 60 is wound around a support roll 64 and a backup roll 62 disposed in a downstream secondary transfer unit 76, which will be described later. The photoconductors 53, primary transfer rolls 57, and intermediate transfer belt 60 constitute a primary transfer unit 72. The positions between the photoconductors 53Y, 53M, 53C, and 53K and the intermediate transfer belt 60 are designated primary transfer positions TY1, TM1, TC1, and TK1, respectively.

[0052] Next, the conveyor belt device 20 will be described in detail.

[0053] As shown in FIG. 1, the conveyor belt device 20 includes an endless conveyor belt 21, support rolls 22 and 23 that support the conveyor belt 21, and secondary transfer rolls 24 and 25 that are positioned opposite the backup rolls 42 and 62 across the intermediate transfer belts 40 and 60.

[0054] The conveyor belt 21 is configured to convey paper to secondary transfer positions TJ2 and TK2 where the toner images formed on the intermediate transfer belts 40 and 60 of the image forming units 30 and 50, respectively, are secondarily transferred. The conveyor belt 21 is also configured so that the toner images formed on the intermediate transfer belts 40 and 60 of the image forming units 30 and 50, respectively, are secondarily transferred when performing misalignment adjustment processing.

[0055] The secondary transfer roll 24 sandwiches the paper PP and the conveyor belt 21 between itself and the backup roll 42, and performs a second transfer of the toner image formed on the intermediate transfer belt 40 of the image forming unit 30 onto the paper PP. Similarly, the secondary transfer roll 25 sandwiches the paper PP and the conveyor belt 21 between itself and the backup roll 62, and performs a second transfer of the toner image formed on the intermediate transfer belt 60 of the image forming unit 50 onto the paper PP.

[0056] The backup roll 42, the secondary transfer roll 24, and the intermediate transfer belt 40 constitute a secondary transfer unit 74. The backup roll 62, the secondary transfer roll 25, and the intermediate transfer belt 60 constitute a secondary transfer unit 76.

[0057] A transfer bias is applied to each of the secondary transfer rolls 24 and 25.

[0058] Further, the space between the intermediate transfer belt 40 of the image forming unit 30 and the conveyor belt 21 is defined as a secondary transfer position TJ2, and the space between the intermediate transfer belt 60 of the image forming unit 50 and the conveyor belt 21 is defined as a secondary transfer position TK2. The secondary transfer position TK2 is the most downstream secondary transfer position.

[0059] The conveyor belt device 20 also includes a belt cleaning device 78 that cleans the conveyor belt 21. The belt cleaning device 78 performs cleaning downstream of the most downstream secondary transfer position TK2 in the paper conveying direction and downstream of a detection device 150 (described later). The position on the conveyor belt 21 that is cleaned by the belt cleaning device 78 is referred to as a cleaning position CL.

[0060] Here, each image forming section 32 of image forming unit 30 and each image forming section 52 of image forming unit 50 form a pattern image for adjusting misalignment using toner of each color (see FIG. 5). Note that the symbols P, S, G, Gr, Y, M, C, and K written after the pattern image BC represent the toner colors, and are omitted when there is no need to distinguish between them.

[0061] In this embodiment, the pattern images BCP, BCS, BCG, and BCGr for adjusting misalignment are formed on the intermediate transfer belt 40, and the pattern images BCY, BCM, BCC, and BCK are formed on the intermediate transfer belt 60, and each is finally secondarily transferred to the conveying belt 21.

[0062] 1, the detection device 150 is provided near the upper end of the conveyor belt 21. The detection device 150 is also provided downstream of the secondary transfer positions TJ2 and TK2 in the conveyance direction in which the paper PP is conveyed by the conveyor belt 21. The detection device 150 is also provided downstream of the most downstream secondary transfer position TK2 in the paper conveyance direction and upstream of the belt cleaning device 78 in the paper conveyance direction.

[0063] The detector 150 is configured to detect the pattern image BC made of the toner image secondarily transferred onto the conveyor belt 21 downstream in the paper conveyance direction of the secondary transfer position TK2 and upstream in the paper conveyance direction of the cleaning position CL.

[0064] In other words, the detection device 150 is disposed at a position where it can detect the pattern image BC downstream in the paper transport direction from the most downstream secondary transfer unit 76. In other words, the detection device 150 is disposed at a position where it can detect all the pattern images BC formed by all the image forming units 32P, 32S, 32G, 32Gr, 52Y, 52M, 52C, and 52K.

[0065] The detection device 150 of this embodiment includes two detection units 150A and 150B arranged at an interval along the axial direction, in other words, the width direction of the conveyor belt 21 (also referred to as the paper width direction or main scanning direction) (see FIG. 6). Two rows of pattern images BC are formed corresponding to the positions of the detection units 150A and 150B. Note that the pattern images BC may be formed in three or more rows in the width direction. In this case, the number of detection units provided is the same as the number of pattern images BC formed in the width direction.

[0066] [Control device] Next, the control device 80 that controls the operation of the image forming apparatus 10 will be described with reference to FIG.

[0067] As shown in FIG. 3, the control device 80 is electrically connected to the image forming unit 30, the image forming unit 50, the detection device 150, the transport section 11, the communication section 90, and the like.

[0068] 3, the control device 80 has a CPU 81 (Central Processing Unit), a ROM 82 (Read Only Memory), a RAM 83 (Random Access Memory), a storage device 85 such as a hard disk drive, and an input / output interface (abbreviated as I / O) 84 that inputs and outputs data to and from each device via a network. These components are connected to one another via a control bus.

[0069] Here, the ROM 82 stores an image formation control program (not shown) that is executed by the CPU 81. The CPU 81 reads the image formation control program (not shown) from the ROM 82 and loads it into the RAM 83, thereby executing printing processing according to the image formation control program (not shown).

[0070] In addition, the I / O 84 is connected to the image forming unit 30, the image forming unit 50, the detection device 150, the conveying unit 11, the communication unit 90, etc. The communication unit 90 is an interface for mutual data communication between the image forming apparatus 10 and a terminal device such as a personal computer.

[0071] The storage device 85 stores the installation positions of the image forming sections 32, 52 for each color in the image forming units 30, 50. When a positional deviation adjustment process is performed, the storage device 85 also stores the amount of deviation and the amount of correction when performing the adjustment process.

[0072] The control device 80 performs various controls for forming toner images on the intermediate transfer belts 40 and 60 by the image forming sections 32 and 52 of the respective colors of the image forming units 30 and 50 .

[0073] The control device 80 also controls the developing biases applied to the developing rolls 39 and 59 of the developing devices 36 and 56. Furthermore, the control device 80 controls the transfer biases applied to the secondary transfer rolls 24 and 25, respectively.

[0074] The control device 80 also controls the timing, time, and amount of toner supplied from the toner cartridges of each color to the developing devices 36 and 56 .

[0075] Furthermore, the control device 80 receives detection values ​​of the pattern images BC detected by the detection device 150. Based on these detection values, the control device 80 calculates the amount of misalignment between the pattern images BC. Based on these detection results, the control device 80 controls the timing of forming toner images on the intermediate transfer belts 40, 60, specifically the exposure timing of each exposure device 35, 55, the development bias applied to each development roll 39, 59, and the transfer bias applied to the secondary transfer rolls 24, 25.

[0076] [Image forming process] Next, an outline of the image forming process in the image forming apparatus 10 will be described.

[0077] First, the control device 80 controls each image forming section 32 so that a toner image is formed on the intermediate transfer belt 40 of the image forming unit 30. Similarly, the control device 80 controls each image forming section 52 so that a toner image is formed on the intermediate transfer belt 60 of the image forming unit 50.

[0078] Specifically, the control device 80 applies a voltage to the charging members 34, 54, which then charge the surfaces of the photoconductors 33, 53 to a predetermined potential. Next, based on image data acquired via the communication unit 90, the control device 80 causes the exposure devices 35, 55 to irradiate light onto the surfaces of the photoconductors 33, 53 charged by the charging members 34, 54, thereby forming electrostatic latent images. As a result, electrostatic latent images corresponding to the image data are formed on the surfaces of the photoconductors 33, 53.

[0079] Next, the control device 80 causes the developing devices 36, 56 to develop the electrostatic latent images formed by the exposure devices 35, 55, and visualize them as toner images. Furthermore, the control device 80 causes the primary transfer rolls 37, 57 to transfer the toner images formed on the surfaces of the photoreceptors 33, 53 of each color onto the intermediate transfer belts 40, 60 in a superimposed manner.

[0080] In this way, in the image forming unit 30, a toner image in which, for example, fluorescent pink (P), silver (S), gold (G), and fluorescent green (Gr) toners are superimposed is formed on the intermediate transfer belt 40. Similarly, in the image forming unit 50, a toner image in which, for example, yellow (Y), magenta (M), cyan (C), and black (K) toners are superimposed is formed on the intermediate transfer belt 60.

[0081] Here, the sheet of paper PP sent out from the storage section 12 to the transport path 19 by the delivery roll 13 has its transport timing adjusted by the registration roll pair 15 under the control of the control device 80, and is then sent out to the secondary transfer position TJ2. At this secondary transfer position TJ2, the sheet of paper PP is transported between the backup roll 42 and the secondary transfer roll 24, so that the toner image on the outer peripheral surface of the intermediate transfer belt 40 is transferred onto the sheet of paper PP. Then, the sheet of paper PP with the toner image transferred thereto is transported downstream in the transport direction, and reaches the secondary transfer position TK2 on the downstream side in the transport direction.

[0082] At this time, the control device 80 adjusts the timing at which image formation begins so that the toner image formed on the intermediate transfer belt 60 of the image forming unit 50 is transferred and superimposed on the toner image on the paper PP transported from the upstream side in the transport direction.

[0083] The paper PP onto which the toner images of each color formed by the image forming units 30 and 50 are superimposed and transferred is fixed by a pair of fixing rolls 16 of the fixing device 18, and then discharged by a discharge roll 17 to a discharge section 9 provided at the top of the image forming device main body 10A.

[0084] [Position adjustment] Next, an example of the process for adjusting positional misalignment (also called color misalignment) in the image forming apparatus 10 will be described with reference to FIGS.

[0085] First, in step S11, the control device 80 determines whether the situation of the image forming device 10 satisfies a preset condition. Examples of preset conditions that can be set include when the image forming device 10 is started up, when it wakes up from sleep mode, when the cover is open, etc. If the situation of the image forming device 10 does not satisfy the preset condition, the process proceeds to step S12, and if the situation satisfies the preset condition, the process proceeds to step S15.

[0086] Here, immediately after starting up the image forming apparatus 10, immediately after waking up from sleep mode, immediately after opening the cover, etc., the temperature change inside the image forming apparatus 10 is greater than before starting up the image forming apparatus 10, before waking up from sleep mode, before opening the cover, etc. If the temperature change inside the image forming apparatus 10 is large, the intermediate transfer belts 40, 60 and endless belts such as the conveyor belt 21 will expand, which may cause deviation in the image formation position. Furthermore, the impact of temperature change will differ depending on the installation positions of the image forming units 30, 50 and the image forming sections 32, 52.

[0087] For this reason, the control device 80 detects, for example, the startup of the image forming device 10, recovery from sleep, or cover opening, and if the temperature change inside the image forming device 10 is greater than the predetermined range, it determines that the situation of the image forming device 10 meets the predetermined conditions and proceeds to processing in step S15.

[0088] In addition, a temperature sensor may be provided within the image forming device 10, and in step S11, the control device 80 may use the temperature detected by the temperature sensor to proceed to processing in step S12 if the temperature change within the image forming device 10 is within a preset range, and proceed to processing in step S15 if the temperature change within the image forming device 10 is greater than the preset range.

[0089] Then, in step S12, the control device 80 uses a predetermined portion of the image forming sections 32, 52 of each image forming unit 30, 50 to primarily transfer a toner image onto the intermediate transfer belts 40, 60, respectively, and then secondarily transfers the toner images primarily transferred onto the intermediate transfer belts 40, 60 onto the conveying belt 21 to form a pattern image BC.

[0090] That is, the control device 80 forms a pattern image BC using some of the image forming sections 32 among the image forming sections 32P, 32S, 32G, and 32Gr of the image forming unit 30, and some of the image forming sections 52 among the image forming sections 52Y, 52M, 52C, and 52K of the image forming unit 50.

[0091] Specifically, the control device 80 forms a pattern image BCGr, for example, as the representative color of the image forming unit 30, using the image forming unit 32Gr that is closest to the secondary transfer position TJ2 among the image forming units 32P, 32S, 32G, and 32Gr of the image forming unit 30. Furthermore, the control device 80 forms a pattern image BCK, for example, as the representative color of the image forming unit 50, using the image forming unit 52K that is closest to the secondary transfer position TK2 among the image forming units 52Y, 52M, 52C, and 52K of the image forming unit 50. That is, as shown in FIG. 5A , the pattern images BCGr and BCK of the representative colors of the image forming units 30 and 50 are formed on the conveyor belt 21 by the image forming unit 32Gr of the image forming unit 30 and the image forming unit 52K of the image forming unit 50.

[0092] Then, in step S13, the control device 80 detects the pattern images BC formed in the representative colors of each image forming unit 30, 50 using the detection device 150, and calculates the amount of misalignment X1 between these pattern images BC. The control device 80 then determines whether the difference between the amount of misalignment X1 detected this time and the amount of misalignment X0 detected the previous time is equal to or less than a preset threshold value of ±X. That is, the control device 80 determines whether the amount of misalignment between the pattern images BC is equal to or less than a preset threshold value. If the difference between the amount of misalignment X1 detected this time and the amount of misalignment X0 detected the previous time is equal to or less than ±X, the process proceeds to step S14; if the difference is greater than ±X, the process proceeds to step S15.

[0093] For example, pattern image BCGr formed by image forming section 32Gr of image forming unit 30 and pattern image BCK formed by image forming section 52K of image forming unit 50 are detected by detection device 150. Then, as shown in Fig. 6, control device 80 calculates the amount of deviation X1 between pattern image BCK and pattern image BCGr detected by detection section 150A and detection section 150B, respectively. For example, control device 80 calculates the amount of deviation X1 in the main scanning direction of the center of gravity of pattern image BCGr relative to the center of gravity of pattern image BCK.

[0094] Next, in step S14, the control device 80 adjusts the misregistration of the toner images formed by all image forming sections 32, 52 of the image forming units 30, 50 based on the image formation positions of the pattern images BC formed by the representative colors, and then ends the process. In this step, first, the control device 80 adjusts the misregistration between the entire image forming unit 30 and the entire image forming unit 50 based on the detection results of the detection device 150. Then, the control device 80 adjusts the misregistration of the image forming sections 32 for each color in the image forming unit 30 and the image forming sections 52 for each color in the image forming unit 50. That is, in this step, the control device 80 predicts and corrects the misregistration of colors that do not form pattern images BC based on the pattern images BC of the representative colors. For example, the control device 80 adjusts the exposure timing of the exposure devices 35P, 35S, 35G, 35Gr, 55Y, 55M, 55C, and 55K so that the detected pattern images BC of the representative colors are positioned in predetermined positions.

[0095] That is, based on the detection result of the detection device 150, the control device 80 adjusts the positional misalignment of the toner images formed by the image forming units 30, 50 for each of the image forming units 30, 50. Then, based on the detection result of the detection device 150, the control device 80 adjusts the positional misalignment of the toner images formed by all of the image forming sections 32, 52 of the image forming units 30, 50.

[0096] In one example, the control device 80 adjusts the overall positional misalignment of the image forming units 30 and 50 based on the amount of misalignment X1 between the center of gravity positions of the pattern images BCK and BCGr. Note that the adjustment of the positional misalignment in this embodiment is performed at the exposure timing of the exposure devices 35 and 55.

[0097] That is, in this step, the image forming section 32Gr in the image forming unit 30 is set as the representative color, and the image forming section 52K in the image forming unit 50 is set as the representative color, and adjustment is made so that the pattern images BCGr and BCK have a predetermined positional relationship. This adjusts the positional misalignment of the entire image forming units 30 and 50.

[0098] In this case, the reading time can be shortened compared to when pattern images BC of all colors are formed on the conveyor belt 21 and misalignment adjustment is performed for all image forming units 32 and 52. Furthermore, since control is easy, the adjustment efficiency is improved.

[0099] In one example, the positional deviation of the image forming sections 32P, 32S, 32G, and 32Gr in the image forming unit 30 is adjusted so that the pattern image BCGr of the representative color of the image forming unit 30 is at a predetermined position and in a predetermined positional relationship with respect to the pattern image BCK of the representative color of the image forming unit 50. Similarly, the positional deviation of the image forming sections 52Y, 52M, 52C, and 52K in the image forming unit 50 may be adjusted so that the pattern image BCK of the representative color of the image forming unit 50 is at a predetermined position and in a predetermined positional relationship with respect to the pattern image BCGr of the representative color of the image forming unit 30.

[0100] Therefore, adjustment efficiency is improved compared to when all of the image forming portions 32P, 32S, 32G, 32Gr, 52Y, 52M, 52C, and 52K are adjusted together for each image forming unit 30, 50.

[0101] That is, the overall positional misalignment of the image forming units 30 and 50 is adjusted using the representative color pattern image BC, and then the positional misalignment of each image forming section 32 in the image forming unit 30 is adjusted, and the positional misalignment of each image forming section 52 in the image forming unit 50 is adjusted. Therefore, adjustment efficiency is improved compared to when all of the image forming sections 32, 52 are adjusted for positional misalignment simultaneously.

[0102] Also, in step S15, if the situation of the image forming device 10 in step S11 meets the preset conditions, or if the amount of deviation between the pattern images BC formed by the representative colors in step S13 is greater than ±X, pattern images BC of all colors are formed on the conveying belt 21 by all image forming sections 32, 52 of the image forming units 30, 50, as shown in Figure 5(B).

[0103] That is, the control device 80 forms pattern images BCP, BCS, BCG, BCGr, BCY, BCM, BCC, and BCK of all colors using image forming sections 32P, 32S, 32G, and 32Gr of the image forming unit 30 and image forming sections 52Y, 52M, 52C, and 52K of the image forming unit 50.

[0104] Next, in step S16, the positional deviation of the toner images formed by all the image forming portions 32, 52 of the image forming units 30, 50 is adjusted based on the pattern images BC of all colors newly formed by all the image forming portions 32, 52, and the process ends. The positional deviation of all the image forming portions 32P, 32S, 32G, 32Gr, 52Y, 52M, 52C, and 52K is adjusted collectively using all the formed pattern images BCP, BCS, BCG, BCGr, BCY, BCM, BCC, and BCK.

[0105] The adjustment of the positional deviation is not limited to the above-described manner, and may be performed by any method.

[0106] As shown in FIGS. 5A and 5B, the number of pattern images BC formed using the representative colors is smaller than the number of pattern images BC formed using all colors. Furthermore, the length of the pattern images BC formed using the representative colors is shorter than the length of the pattern images BC formed using all colors. Therefore, the reading time of the pattern images BC formed using the representative colors can be shortened compared to the reading time of the pattern images BC formed using all colors. As a result, the time required to adjust the misalignment using the pattern images BC formed using the representative colors can be shortened compared to the time required to adjust the misalignment using the pattern images BC formed using all colors. On the other hand, when the status of the image forming apparatus 10 meets preset conditions or when the amount of misalignment between the current detection result and the previous detection result is large, the adjustment accuracy can be improved by using the pattern images BC formed using all colors compared to the pattern images BC formed using the representative colors. In other words, by performing the adjustment process by forming pattern images using the representative colors or all colors according to preset conditions, misalignment between the image forming units can be efficiently adjusted.

[0107] In this embodiment, the detection device 150 detects the pattern image BC that has been secondarily transferred onto the conveying belt 21, and therefore the detection accuracy is improved compared to when detecting the pattern image BC that has been secondarily transferred onto paper PP whose surface condition varies depending on the material, etc.

[0108] Furthermore, the image forming portion 32Gr, which is the representative color of the image forming unit 30, and the image forming portion 52K, which is the representative color of the image forming unit 50, are located in the same position when counted upstream from the secondary transfer positions TJ2 and TK2, respectively. This improves the accuracy of misregistration adjustment compared to when the positions of the image forming portions used as references are different.

[0109] In this way, by reducing the number of colors in the pattern images BC formed by the image forming sections 32 and 52 of the image forming units 30 and 50, the adjustment efficiency of misregistration is improved compared to when all colors are used. Also, the amount of toner consumed in misregistration adjustment can be reduced compared to when all colors are used. Also, the adjustment time for misregistration adjustment can be shortened compared to when all colors are used, thereby improving productivity.

[0110] <Other forms> The present invention is not limited to the above embodiment.

[0111] For example, in the above embodiment, the detection device 150 that detects the pattern image BC secondarily transferred onto the conveyor belt 21 is provided downstream of the multiple secondary transfer positions TJ2 and TK2, but is not limited to this. The detection device 150 may also be provided in other locations.

[0112] Furthermore, a detection device for detecting the pattern image BC may be further provided between the most downstream primary transfer positions TGr1, TK1 on the intermediate transfer belts 40, 60 and the secondary transfer positions TJ2, TK2.

[0113] In the above embodiment, when misregistration is adjusted, the pattern images BCGr and BCK are formed as representative colors by the image forming units 32Gr and 52K that are closest to the secondary transfer positions TJ2 and TK2 of the image forming units 30 and 50, respectively. However, this is not limiting. The pattern images may be formed by the image forming unit of the color with the lowest reflectance in each of the image forming units 30 and 50. This improves the detection accuracy of the formed pattern images.

[0114] Furthermore, the pattern image may be formed by the image forming section of the least expensive color in each of the image forming units 30 and 50. This makes it possible to reduce the amount of toner consumed for expensive colors.

[0115] In the above embodiment, the pattern images BCGr and BCK are formed by one image forming section 32Gr and one image forming section 52K from each of the image forming units 30 and 50, respectively, and the amount of misalignment between the two colors is detected, but this is not limiting. The pattern image BC may be formed by one or more image forming sections 32 and 52 from each of the image forming units 30 and 50, respectively, and the amount of misalignment may be detected. Furthermore, the pattern image BC may be formed by one or more different numbers of image forming sections 32 and 52 from each of the image forming units 30 and 50, respectively, and the amount of misalignment may be detected.

[0116] In the above embodiment, the positional deviation adjustment is performed using a pattern image of a representative color or all colors, but the present invention is not limited to this. Color adjustment other than the positional deviation adjustment, such as density adjustment, may also be performed.

[0117] In the above embodiment, the image forming apparatus 10 includes two image forming units, the image forming unit 30 and the image forming unit 50, but this is not limiting. The image forming apparatus may include three or more image forming units. In addition, the image forming units 30 and 50 each include four image forming sections 32 and 52, but this is not limiting.

[0118] In the above embodiment, the detection device 150 is configured to detect the pattern image BC that has been secondarily transferred onto the conveyor belt 21, but the present invention is not limited to this. The detection device 150 may be configured to detect the pattern image BC that has been secondarily transferred onto the paper PP.

[0119] The configuration of the image forming apparatus is not limited to that of the above embodiment, and various other configurations are possible. Furthermore, the present invention can be embodied in various forms without departing from the spirit and scope of the present invention.

[0120] Furthermore, in the above embodiments, the term "processor" refers to a processor in a broad sense, and includes general-purpose processors (e.g., CPUs, etc.) and dedicated processors (e.g., GPUs: Graphics Processing Units, ASICs: Application Specific Integrated Circuits, FPGAs: Field Programmable Gate Arrays, programmable logic devices, etc.).

[0121] Furthermore, the operations of the processors in the above embodiments may not only be performed by a single processor, but may also be performed by multiple processors located at physically separate locations working together. Furthermore, the order of the operations of the processors is not limited to the order described in the above embodiments, and may be changed as appropriate.

[0122] The techniques of this disclosure are also applicable to programs and program products.

[0123] [Note] Preferred embodiments of the present disclosure will be described below.

[0124] (((1))) a plurality of image forming units each having a plurality of image forming sections and an intermediate transfer body onto which the toner images formed by the plurality of image forming sections are primarily transferred; a conveyor belt that conveys paper to a secondary transfer position where the toner images formed on the intermediate transfer bodies of the plurality of image forming units are secondarily transferred; a detection device that is provided downstream of the plurality of secondary transfer positions in a conveying direction in which the paper is conveyed by the conveyor belt, and that detects a pattern image formed by the toner image secondarily transferred onto the conveyor belt; a processor, The processor: When adjusting the positional deviation of the toner image, a predetermined part of the image forming sections of each of the plurality of image forming units is used to primarily transfer the toner image onto the intermediate transfer body, and the toner image primarily transferred onto the intermediate transfer body is secondarily transferred onto the conveyor belt to form the pattern image. Image forming device.

[0125] (((2))) The image forming apparatus described in (((1)))), wherein the processor adjusts the positional misalignment of the toner images formed by each of the multiple image forming units based on the detection results of the detection device, for each of the multiple image forming units.

[0126] (((3))) The image forming apparatus described in (((1))) or (((2))), wherein the processor adjusts the positional misalignment of the toner images formed by all of the image forming sections of the multiple image forming units based on the detection results of the detection device.

[0127] (((4))) the plurality of image forming units include a first image forming unit and a second image forming unit, The processor: The image forming apparatus described in (((3)))) further comprises: when the misalignment of the pattern images formed by the predetermined first image forming portion of the first image forming unit and the predetermined second image forming portion of the second image forming unit detected by the detection device is equal to or less than a predetermined threshold, the image forming apparatus adjusts the misalignment of the toner images formed by all of the image forming portions of the first image forming unit and the second image forming unit based on the formed pattern images.

[0128] (((5))) The processor: The image forming apparatus described in (((4)))), wherein, when the misalignment of the pattern image detected by the detection device is greater than a preset threshold, a new pattern image is formed on the conveying belt by all image forming sections of the first image forming unit and the second image forming unit, and based on the newly formed pattern image, the positional misalignment of the toner images formed by all image forming sections of the first image forming unit and the second image forming unit is adjusted.

[0129] (((6))) The image forming apparatus described in (((1)))) is configured such that, when the status of the apparatus satisfies a preset condition, the processor forms a pattern image on the conveying belt using all image forming sections of the plurality of image forming units.

[0130] (((7))) The image forming apparatus described in (((6))) is configured such that, when the temperature change within the apparatus exceeds a predetermined range, the processor forms a pattern image on the conveying belt using all image forming sections of the plurality of image forming units.

[0131] (((8))) The image forming apparatus according to (((1))), wherein the image forming section used when adjusting the positional misalignment of the toner image is the image forming section that is closest to the secondary transfer position in each of the image forming units.

[0132] (((9))) The image forming apparatus according to (((1))), wherein the image forming section used when adjusting the positional misalignment of the toner image is the image forming section of the color with the lowest reflectance in each of the image forming units.

[0133] (((10))) When adjusting the positional deviation of the toner images, a step of primarily transferring the toner images onto the intermediate transfer body by using a predetermined part of the image forming parts of each of a plurality of image forming units, each of which has a plurality of image forming parts and an intermediate transfer body onto which the toner images formed by the plurality of image forming parts are primarily transferred; a step of forming a pattern image by secondarily transferring the toner image primarily transferred onto the intermediate transfer body onto a conveyor belt that conveys paper to a secondary transfer position; detecting the pattern image by a detection device; A program that causes a computer to execute the following.

[0134] The effects of the configuration described above will be described below.

[0135] According to the image forming apparatus (((1))), the time required to adjust misalignment can be shortened compared to when pattern images are formed by all image forming sections provided in multiple image forming units and misalignment is adjusted.

[0136] According to the image forming apparatus (((2))), the time required to adjust misalignment can be shortened compared to when pattern images are formed by all image forming sections of a plurality of image forming units and misalignment is adjusted.

[0137] According to the image forming apparatus (((3))), the time required to adjust misalignment can be shortened compared to when pattern images are formed by all image forming sections of a plurality of image forming units and misalignment is adjusted.

[0138] According to the image forming apparatus of (((4))), the time required for adjusting misalignment can be shortened compared to when misalignment is adjusted using pattern images formed by all image forming units.

[0139] According to the image forming apparatus of (((5))), the accuracy of misalignment adjustment can be improved compared to when misalignment is adjusted using pattern images formed by two image forming units.

[0140] According to the image forming apparatus of (((6))), it is possible to improve the accuracy of adjusting misalignment in a situation where misalignment of the image formation position is likely to occur.

[0141] According to the image forming apparatus of (((7))), it is possible to improve the accuracy of adjusting misregistration in a situation where a temperature rise inside the apparatus easily causes a misregistration in the image forming position.

[0142] According to the image forming apparatus of (((8))), the influence of the intermediate transfer body can be reduced and the accuracy of adjusting misregistration can be improved.

[0143] According to the image forming apparatus of (((9))), the accuracy of adjusting misregistration can be improved compared to when an image forming unit of a color with high reflectance is used.

[0144] According to the program (((10))), the time required to adjust misalignment can be shortened compared to when pattern images are formed by all image forming sections of a plurality of image forming units and misalignment is adjusted. [Explanation of symbols]

[0145] 10 Image forming device 21 Conveyor belt 30 Image forming unit 50 Image forming unit 150 Detection Device

Claims

1. a plurality of image forming units each having a plurality of image forming sections and an intermediate transfer body onto which the toner images formed by the plurality of image forming sections are primarily transferred; a conveyor belt that conveys paper to a secondary transfer position where the toner images formed on the intermediate transfer bodies of the plurality of image forming units are secondarily transferred; a detection device that is provided downstream of the plurality of secondary transfer positions in a conveying direction in which the paper is conveyed by the conveyor belt, and that detects a pattern image formed by the toner image secondarily transferred onto the conveyor belt; a processor, The processor: When adjusting the positional deviation of the toner image, a predetermined part of the image forming sections of each of the plurality of image forming units is used to primarily transfer the toner image onto the intermediate transfer body, and the toner image primarily transferred onto the intermediate transfer body is secondarily transferred onto the conveyor belt to form the pattern image. Image forming device.

2. The image forming apparatus according to claim 1 , wherein the processor adjusts the positional deviation of the toner images formed by the plurality of image forming units for each of the plurality of image forming units based on the detection result of the detection device.

3. 2. The image forming apparatus according to claim 1, wherein the processor adjusts misalignment of the toner images formed by all of the image forming sections of the plurality of image forming units based on the detection result of the detection device.

4. the plurality of image forming units include a first image forming unit and a second image forming unit, The processor:

4. The image forming apparatus according to claim 3, wherein, when the misalignment of the pattern images formed by the predetermined first image forming portion of the first image forming unit and the predetermined second image forming portion of the second image forming unit detected by the detection device is equal to or less than a predetermined threshold, the image forming apparatus adjusts the positional misalignment of the toner images formed by all image forming portions of the first image forming unit and the second image forming unit based on the formed pattern images.

5. The processor:

5. The image forming apparatus according to claim 4, wherein, when the misalignment of the pattern image detected by the detection device is greater than a predetermined threshold, a new pattern image is formed on the conveying belt by all image forming sections of the first image forming unit and the second image forming unit, and based on the newly formed pattern image, the positional misalignment of the toner images formed by all image forming sections of the first image forming unit and the second image forming unit is adjusted.

6. 2. The image forming apparatus according to claim 1, wherein the processor forms pattern images on the conveyor belt by all image forming sections of the plurality of image forming units when the state of the apparatus satisfies a preset condition.

7. 7. The image forming apparatus according to claim 6, wherein the processor forms a pattern image on the conveyor belt by all image forming sections of the plurality of image forming units when a temperature change within the apparatus exceeds a predetermined range.

8. 2. The image forming apparatus according to claim 1, wherein the image forming section used when adjusting the positional deviation of the toner image is the image forming section that is closest to the secondary transfer position in each of the image forming units.

9. 2. The image forming apparatus according to claim 1, wherein the image forming section used when adjusting the positional deviation of the toner image is the image forming section of the color having the lowest reflectance in each of the image forming units.

10. When adjusting the positional deviation of the toner images, a step of primarily transferring the toner images onto the intermediate transfer body by using a predetermined part of the image forming parts of each of a plurality of image forming units, each of which has a plurality of image forming parts and an intermediate transfer body onto which the toner images formed by the plurality of image forming parts are primarily transferred; a step of forming a pattern image by secondarily transferring the toner image primarily transferred onto the intermediate transfer body onto a conveyor belt that conveys paper to a secondary transfer position; detecting the pattern image by a detection device; A program that causes a computer to execute the following.

Images