JP5207158B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an electrophotographic image forming apparatus such as a printer or a copying machine, and more particularly to an image forming apparatus that forms an image on an image carrier such as an AIO cartridge or an intermediate transfer belt and transfers the image onto a transfer material.

  In a conventional electrophotographic image forming apparatus, an endless belt of medium resistance or high resistance is used as an intermediate transfer belt. The endless belt is stretched around a plurality of rollers arranged in parallel to each other. The intermediate transfer belt is driven by rotating the roller. In the image forming apparatus using the intermediate transfer belt, the surface of the intermediate transfer belt may be damaged due to friction with transfer paper or the like during the recovery process when a jam occurs. In addition, a foreign object attached to a cleaning blade that contacts the intermediate transfer belt and removes residual toner may be damaged. For this reason, the image transferred to the transfer paper is also scratched, causing an image defect.

  In addition, when the image forming apparatus is not used for a while, the intermediate transfer belt may be curled due to a roller that stretches the intermediate transfer member. In addition, cracks may occur due to secular change, and a defective portion having a resistance value different from that of other portions may occur. Due to such deformation or defect of the intermediate transfer belt, a transfer failure in which the hue becomes abnormal is caused. Further, in an apparatus that forms an inspection image pattern on the intermediate transfer belt and performs color matching and density correction of each color based on the inspection image pattern, a normal correction result is obtained by forming the inspection image pattern on the scratch. May not be obtained.

  Various measures have been taken to overcome such problems. For example, a reference pattern is provided at a reference position on the intermediate transfer belt. The relative positional relationship from the reference position to a defect position such as a scratch is grasped. An image is formed avoiding a defect position, or an image is formed so that the influence of the defect is reduced. Examples of related art related to this will be given below.

  The “image forming apparatus” disclosed in Patent Document 1 uses a region other than the defect position of the intermediate transfer member, thereby enabling high-quality image formation at a low cost over a long period of time. Defect position information is input in advance. When the electrostatic latent image is converted into a toner image and toner images of different colors are sequentially superimposed and transferred onto the intermediate transfer member, the reference position of the intermediate transfer member is detected. Based on this, the relative position of the intermediate transfer member with respect to the electrostatic latent image is controlled according to the defect position information.

  However, the conventional method of forming a test image pattern and performing color matching processing and density adjustment processing has the following problems. Since the inspection image pattern cannot be formed on the intermediate transfer belt at the timing when the defect enters the inspection image pattern, it is necessary to wait until the defect passes the transfer position. Further, when there are a plurality of defects, an area where an inspection image pattern can be formed on the intermediate transfer belt is limited.

  SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems and store information on feature points such as scratches on an intermediate transfer member in an image forming apparatus and form an inspection image pattern so as to overlap the feature points. Thus, even if the state of the intermediate transfer member is bad, it is not affected. That is, by removing or avoiding all feature points or setting an error of the intermediate transfer member, the accuracy of the adjustment process is increased, the adjustment process time is shortened, and the deterioration of the image quality is prevented.

  In order to solve the above problems, in the present invention, a latent image carrier, a latent image forming unit that forms a latent image on the latent image carrier, and a developing unit that develops the latent image to form a visible image. Intermediate transfer means for transferring the visible image to the intermediate transfer body, intermediate transfer position detection means for determining the position of the intermediate transfer body, and the intermediate transfer body by reflected light irradiated on the intermediate transfer body An image forming apparatus comprising: surface information detection means for detecting surface information on the surface; and feature point storage means for storing feature point information obtained by detecting feature points on the intermediate transfer member by the surface information detection means. In the intermediate transfer position detecting means, an inspection image pattern forming means for forming an inspection image pattern for determining the position of the intermediate transfer member, and forming the inspection image pattern on the feature point, Before feature point A feature point removal determination unit that determines whether or not the feature point can be effectively removed without being detected by a surface information detection unit; and the inspection image pattern that is determined to be able to be removed effectively. Forming control means for controlling the formation timing so as to remove the feature points.

  Further, the inspection image pattern forming means includes means for forming the inspection image pattern in a plurality of colors, and the feature point removal determining means is a color that can most effectively remove the feature points based on the feature point information. A means for determining is provided. The feature point removal determination means includes means for determining that the intermediate transfer member cannot be used when the feature point cannot be removed even with a color that can most effectively remove the feature point. The feature point removal determination means includes means for determining whether or not a plurality of feature points can be removed with one inspection image pattern, and the formation control means determines that all feature points are determined according to the determination that the feature points can be removed. Means for controlling to superimpose the inspection image patterns, and means for forming the inspection image pattern so as to avoid all feature points in accordance with the determination that the inspection image patterns cannot be removed. Means for controlling the formation control means to form the inspection image pattern on all the feature points by changing the interval of the inspection image pattern so as to overlap all the feature points in accordance with the determination that it can be removed. Is provided.

  Further, the feature point removal determination means includes means for determining whether or not the distance between the feature points is removable and is short enough, and the formation control means is determined to be removable and short enough. And a means for widening the inspection image pattern in accordance with the control to form the inspection image pattern on all feature points. The feature point removal determining means includes means for determining whether or not the distance between the feature points is longer than the width of the inspection image pattern but can be removed, and the formation control means removes the feature point removal determination means. In response to determining that the length is possible, the inspection image pattern is widened to control the inspection image pattern to be formed on all feature points.

  By configuring as described above, all the feature points of the intermediate transfer member of the image forming apparatus can be removed or avoided effectively and reliably, so that the accuracy of each adjustment process can be improved and the adjustment process time can be shortened. Can be prevented.

1 is a conceptual diagram illustrating a basic configuration of an image forming apparatus in Embodiment 1 of the present invention. FIG. 3 is a functional block diagram of a portion related to reference position adjustment of the image forming apparatus according to the first exemplary embodiment of the present invention and an explanatory diagram of an inspection image pattern. 3 is a flowchart illustrating a storage control procedure for surface information of an intermediate transfer belt of the image forming apparatus according to the first exemplary embodiment of the present invention. 5 is a flowchart illustrating a procedure for forming an inspection image pattern during color matching adjustment processing of the image forming apparatus according to the first exemplary embodiment of the present invention. It is a flowchart which shows the procedure which forms the test | inspection image pattern with the color which can remove most feature points in the image forming apparatus in Example 2 of this invention. It is a flowchart which shows the procedure which removes all the feature points with one test | inspection image pattern with the image forming apparatus in Example 3 of this invention. It is a flowchart which shows the procedure which changes the space | interval and forms a test | inspection image pattern in the image forming apparatus in Example 4 of this invention. It is a flowchart which shows the procedure which changes the width | variety and forms a test | inspection image pattern in the image forming apparatus in Example 5 of this invention. It is a flowchart which shows the procedure in which the width | variety is widened and the test | inspection image pattern is formed in the image forming apparatus in Example 6 of this invention.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to FIGS.

  In the first embodiment of the present invention, defect information such as scratches on the intermediate transfer belt is stored in advance as feature points, and an inspection image pattern is formed so as to overlap the feature points to effectively remove the feature points. Forming device.

FIG. 1 is a conceptual diagram showing a basic configuration of an image forming apparatus in Embodiment 1 of the present invention.
The basic configuration of the image forming apparatus is the same as that of a conventional apparatus. The means for forming the inspection image pattern is different from the conventional apparatus. In FIG. 1, a sheet 104 is printing paper. The intermediate transfer belt 105 is an endless belt wound around a secondary transfer drive roller and a transfer belt tension roller that are driven to rotate. The AIO cartridge 106 is an image forming unit that forms an image of each color. The secondary transfer drive roller 107 is a unit that is driven to rotate by a drive motor and drives the intermediate transfer belt. The transfer belt tension roller 108 is auxiliary drive means for the intermediate transfer belt. The photoconductor 109 is a drum on which an electrostatic latent image is formed.

  The charger 110 is a means for charging the photoconductor. The exposure device 111 is means for irradiating the photosensitive member with laser light. The developing device 112 is a means for visualizing the electrostatic latent image with toner. The cleaner blade 113 is a means for wiping off unnecessary residual toner. The laser beam 114 is light having an intensity corresponding to the image. The primary transfer roller 115 is means for transferring the toner image on the photosensitive member to the intermediate transfer belt. The secondary transfer roller 116 is means for transferring the toner image on the intermediate transfer belt to a sheet. The TM sensor 117 is a sensor that acquires surface information of the intermediate transfer belt.

  FIG. 2 is a functional block diagram of a portion related to the reference position adjustment and an explanatory diagram of the inspection image pattern. In FIG. 2, a ROM 200 is a fixed memory that stores a control program and the like. The RAM 201 is a temporary memory that stores data being processed. The EEPROM 202 is a rewritable nonvolatile memory that stores parameters and the like. The surface information detection sensor 203 is a TM sensor that acquires surface information of the intermediate transfer belt. The primary transfer bias 204 is a bias for transferring the toner image to the intermediate transfer belt. The polygon motor 205 is a motor that drives a mirror that deflects laser light. The laser 206 is means for generating laser light that forms a latent image. The development bias 207 is a bias for visualizing the latent image with toner. The intermediate transfer position detection sensor 208 is a sensor that detects the position of the intermediate transfer belt.

  FIG. 3 is a flowchart showing a storage control procedure for the surface information of the intermediate transfer belt of the image forming apparatus. FIG. 4 is a flowchart showing a procedure for forming an inspection image pattern during the color matching adjustment process.

  The function and operation of the image forming apparatus according to Embodiment 1 of the present invention configured as described above will be described. First, the basic operation of the tandem image forming apparatus will be described with reference to FIG. The basic operation of the image forming apparatus is the same as that of a conventional apparatus. The operation of the color matching adjustment process described later is different from the conventional apparatus. Along with the intermediate transfer belt 105, AIO cartridges (106Bk, 106M, 106C, 106Y) of the respective colors are arranged. The intermediate transfer belt 105 rotates counterclockwise. A plurality of AIO cartridges (electrophotographic process units) 106Bk, 106M, 106C, 106Y are arranged in order from the upstream side in the rotation direction. The plurality of AIO cartridges 106Bk, 106M, 106C, and 106Y have the same internal configuration except that the color of the toner image to be formed is different. The AIO cartridge 106Bk forms a black image, the AIO cartridge 106M forms a magenta image, the AIO cartridge 106C forms a cyan image, and the AIO cartridge 106Y forms a yellow image.

  In the following description, the AIO cartridge 106Bk will be described in detail. However, since the other AIO cartridges 106M, 106C, and 106Y are the same as the AIO cartridge 106Bk, each component of the AIO cartridge 106M, 106C, and 106Y is described. Instead of Bk attached to each component of the AIO cartridge 106Bk, only the symbols distinguished by M, C, and Y are displayed in the figure, and the description is omitted. The intermediate transfer belt 105 is an endless belt wound around a secondary transfer driving roller 107 and a transfer belt tension roller 108 that are rotationally driven. The secondary transfer drive roller 107 is driven to rotate by a drive motor (not shown), and the drive motor, the secondary transfer drive roller 107, and the transfer belt tension roller 108 move the intermediate transfer belt 105. Function as. The AIO cartridge 106Bk includes a photoconductor 109Bk as a photoconductor, a charger 110Bk arranged around the photoconductor 109Bk, an exposure device 111, a developing device 112Bk, a cleaner blade 113Bk, and the like. The exposure device 111 is configured to irradiate laser beams 114Bk, 114M, 114C, and 114Y that are exposure lights corresponding to the image colors formed by the AIO cartridges 106Bk, 106M, 106C, and 106Y.

  When forming an image, the outer peripheral surface of the photoreceptor 109Bk is uniformly charged by the charger 110Bk in the dark, and then exposed by the laser beam 114Bk corresponding to the black image from the exposure device 111 to form an electrostatic latent image. Is done. The developing device 112Bk visualizes the electrostatic latent image with black toner, thereby forming a black toner image on the photoreceptor 109Bk. This toner image is transferred onto the intermediate transfer belt 105 by the action of the primary transfer roller 115Bk at a position (primary transfer position) where the photoreceptor 109Bk and the intermediate transfer belt 105 are in contact with each other. By this transfer, an image of black toner is formed on the intermediate transfer belt 105. After the transfer of the toner image is completed, the photosensitive member 109Bk waits for the next image formation after the unnecessary toner remaining on the outer peripheral surface is wiped off by the cleaner blade 113Bk.

  As described above, the intermediate transfer belt 105 to which the black toner image is transferred by the AIO cartridge 106Bk is conveyed to the next AIO cartridge 106M by the intermediate transfer belt 105. In the AIO cartridge 106M, a magenta toner image is formed on the photoreceptor 109M by a process similar to the image forming process in the AIO cartridge 106Bk, and the toner image is superimposed on the black image formed on the intermediate transfer belt 105. And is transcribed.

  The intermediate transfer belt 105 is further conveyed to the next AIO cartridges 106C and 106Y, and a cyan toner image formed on the photoconductor 109C and a yellow toner image formed on the photoconductor 109Y by the same operation. Are superimposed and transferred onto the intermediate transfer belt. Thus, a full-color image is formed on the intermediate transfer belt 105. The intermediate transfer belt 105 on which the full-color superimposed image is formed is conveyed to the position of the secondary transfer roller 116, and the secondary transfer roller 116 is in contact with the intermediate transfer belt 105 and the secondary transfer roller 116 (secondary transfer position). The image is transferred to the conveyed sheet 104 by the function of the transfer roller 116. In the case of printing only black at the time of image formation, the primary transfer roller 115M, the primary transfer roller 115C, and the primary transfer roller 115Y are positioned away from the photoconductor 109M, the photoconductor 109C, and the photoconductor 109Y, respectively. The above-described image forming process is performed only for black.

  Next, the basic operation of the color matching adjustment process will be described with reference to FIG. Although only the color matching adjustment process will be described, the present invention is not limited to color matching but can be applied to various adjustment processes for forming an inspection image pattern such as density adjustment. In the latent image forming means, the polygon motor 205 is rotated. When the rotation is stabilized, the laser 206 is irradiated. Subsequently, an image is formed on the intermediate transfer belt by applying a developing bias 207 in the developing unit and applying a primary transfer bias 204 in the intermediate transfer unit. The image on the intermediate transfer belt is detected by the surface information detection sensor 203 (TM sensor 117 in FIG. 1) of the surface information detection means, and the position of the intermediate transfer belt is detected by the intermediate transfer position detection sensor 208 of the intermediate transfer position detection means. Store to EEPROM if necessary.

  Next, an inspection image pattern at the time of color matching adjustment processing will be described with reference to FIG. An image pattern obtained by combining a rectangular pattern formed in the order of Y, Bk, C, and M and an oblique line pattern in the sub-scanning direction on the intermediate transfer belt 105 is set as one set. This is an inspection image pattern. Here, in the inspection image pattern, the length L1 (pattern width) in the sub-scanning direction of the rectangular pattern of each color, the distance L2 (pattern interval) between each color, and the length L3 in the sub-scanning direction (total pattern length) Has a predetermined value. A plurality of sets of the inspection image patterns are formed, and the color registration adjustment processing is performed by calculating the shift amount of each color such as the skew amount of each color, the sub-scanning registration position shift, and the main scanning registration position shift.

  Next, with reference to FIG. 2C, a description will be given of the pattern reading principle at the time of forming the inspection image pattern and the erroneous detection when there is a feature point such as a defect on the intermediate transfer belt. First, a TM sensor is arranged on the intermediate transfer belt, and when the sensor waveform becomes higher than a certain value, it is determined that there is an image pattern at the TM sensor position. However, if there are feature points T1 and T2 on the intermediate transfer belt, and the feature point T2 has a sensor waveform longer than a certain value T1, the feature point T2 is erroneously recognized as an image pattern. Here, the length T2L of the feature point T2 in the sub-scanning direction is defined as the feature point width.

  Next, a storage control procedure for the surface information of the intermediate transfer belt 105 of the image forming apparatus will be described with reference to FIG. In Step 100, the rotation of the intermediate transfer belt 105 is started in a state where no image is formed on all the photoreceptors 109Bk to 109Y. In step 101, a reference position on the intermediate transfer belt is detected by a reference position detection sensor. When the reference position is detected, in step 102, acquisition of surface information is started using the TM sensor 117. When it is detected in step 103 that there is a defect such as a scratch on the intermediate transfer belt 105, in step 104, information on the distance from the reference position and the feature point width is stored as feature point information. In step 105, this feature point detection and storage process is repeated until the reference position is detected again, and all feature points on the intermediate transfer belt 105 are stored. If the reference position is detected again, in step 106, the feature point detection ends.

  Next, a procedure for forming an inspection image pattern during the color matching adjustment process will be described with reference to FIG. In step 200, rotation of the intermediate transfer belt 105 is started in a state where no image is formed on all the photosensitive members 109Bk to 109Y. In step 201, a reference position of the intermediate transfer belt 105 is detected by a reference position detection sensor (not shown). After detecting the reference position, in step 202, the distance to the next feature point position is compared with the total pattern length to check whether the inspection image pattern can be formed. If the total pattern length is shorter, in step 203, one set of inspection image pattern is formed. If the total pattern length is longer, in step 204, the feature point width is compared with the pattern width to check whether the feature point can be removed. To be able to remove a feature point is not to actually remove the feature point but to make it impossible to detect it by the surface information detection sensor so as to effectively eliminate the interference by the feature point.

If the pattern width is longer, it is determined that the feature point can be removed by forming the inspection image pattern on the feature point. If the feature point can be removed, in order to shorten the processing time, in step 205, the color of the image pattern to be superimposed is determined in preference to the color in which the image is formed in order. In this example, the priority is higher in the order of M>C>Bk> Y. In step 206, an image is formed so that the inspection image pattern overlaps the feature point. If the pattern width is shorter, it is determined that the feature point cannot be removed, and in step 207, the process waits until the feature point passes.
The above processing is repeated in step 208 until the number of inspection image pattern sets necessary for the color matching adjustment processing is formed.

  As described above, in Embodiment 1 of the present invention, the image forming apparatus stores defect information such as scratches on the intermediate transfer belt as feature points in advance, and forms an inspection image pattern so as to overlap the feature points. Therefore, the feature points can be effectively removed, so that the feature points can be reliably removed, the adjustment processing accuracy can be improved, and the adjustment processing time can be shortened.

  In the second embodiment of the present invention, defect information such as scratches on the intermediate transfer belt is stored in advance as feature points, and the inspection image pattern is formed so as to overlap the feature points in a color that can most effectively remove the feature points. Thus, the image forming apparatus effectively removes the feature points.

  FIG. 5 is a flowchart showing a procedure for forming an inspection image pattern with a color that can most effectively remove feature points in the image forming apparatus according to the second embodiment of the present invention. The basic configuration of the image forming apparatus in the second embodiment is the same as that in the first embodiment, but the method for forming the inspection image pattern is different.

  When the difference between the feature point width and the pattern width is small, the feature point may not be removed depending on the color of the image pattern formed on the feature point. This is because the TM sensor 117 detects the intermediate transfer belt surface information by the reflected light of the sensor, and the detection accuracy also changes depending on the toner characteristics. Therefore, the feature point removal characteristics of each color are stored in advance, and when the difference between the feature point width and the pattern width is small, a color image pattern capable of removing the feature points most effectively is formed.

With reference to FIG. 5, a procedure for forming an inspection image pattern during the color matching adjustment process will be described.
In step 300, rotation of the intermediate transfer belt 105 is started in a state where images are not formed on all the photosensitive members 109Bk to 109Y. In step 301, a reference position of the intermediate transfer belt 105 is detected by a reference position detection sensor (not shown). After detecting the reference position, in step 302, the distance to the next feature point position is compared with the total pattern length to check whether the inspection image pattern can be formed. If the total pattern length is shorter, a set of inspection image patterns is formed in step 303. If the total pattern length is longer, in step 304, the feature point width is compared with the pattern width to check whether the feature point can be removed.

  If the pattern width is longer, it is determined that the feature point can be removed by forming the inspection image pattern on the feature point. If it can be removed, in step 305, the difference between the feature point width and the pattern width is examined. If the difference is small, in step 306, the inspection image pattern is formed so that the colors that can remove most feature points overlap. If the difference between the feature point width and the pattern width is large, in step 308, priority is given to the color in which the order of image formation is slow. If the pattern width is shorter, it is determined that the feature point cannot be removed, and in step 309, the process waits until the feature point passes. The above process is repeated in step 310 until the number of sets of inspection image patterns necessary for the color matching adjustment process is formed.

  Even if colors that can remove feature points most effectively are superimposed, if feature points cannot be removed, highly accurate color matching adjustment processing cannot be executed. In addition, even during normal printing, the feature point portion becomes noise and the image quality is degraded. Therefore, if the feature point cannot be removed, it is determined that the intermediate transfer belt 105 cannot be used. The inspection image pattern formation flow at the time of color matching adjustment processing is the same as that in FIG.

  As described above, in the second embodiment of the present invention, the image forming apparatus stores defect information such as scratches on the intermediate transfer belt as feature points in advance, and inspects the color with the color that can most effectively remove the feature points. Since the image pattern is formed so as to overlap the feature points and the feature points are effectively removed, the feature points can be removed reliably, the adjustment processing accuracy can be improved, and the adjustment processing time can be shortened.

  In the third embodiment of the present invention, defect information such as scratches on the intermediate transfer belt is stored in advance as feature points, and the inspection image pattern is formed so as to overlap the feature points. Is an image forming apparatus that effectively removes.

FIG. 6 is a flowchart showing a procedure for removing all feature points in one inspection image pattern.
The basic configuration of the image forming apparatus in the third embodiment is the same as that in the first embodiment, but the method for forming the inspection image pattern is different.

  When there are a plurality of feature points, the first feature point can be removed by the image pattern, but if the second feature point is in the image pattern formed to remove the first feature point, The feature point may not be removed. Therefore, it is determined whether or not feature points can be removed for all feature points in one set of inspection image patterns, and an image pattern is formed.

  A procedure for forming a predetermined image pattern during the color matching adjustment process will be described with reference to FIG. In step 400, rotation of the intermediate transfer belt 105 is started in a state where images are not formed on all the photosensitive members 109Bk to 109Y. In step 401, a reference position of the intermediate transfer belt 105 is detected by a reference position detection sensor (not shown). After detecting the reference position, in step 402, the distance to the next feature point position is compared with the total pattern length to check whether the inspection image pattern can be formed. If the total pattern length is shorter, in step 403, a set of predetermined image patterns is formed. If the total pattern length is longer, in step 404, the feature point width is compared with the pattern width to check whether the feature point can be removed. If the pattern width is longer, it is determined that the feature point can be removed by forming a predetermined image pattern on the feature point.

  If removal is possible, in step 405, the color of the image pattern to be overlaid is determined in preference to the color in which the image is formed in order. For example, the order is M> C> Bk> Y. Here, it is assumed that feature point removal has been performed with the image pattern of the determined color, and in step 406, it is checked whether or not the next feature point falls within one set of image patterns. If not, in step 407, a predetermined image pattern is formed. If yes, in step 408, whether or not the image pattern just overlaps the feature point, the feature point width and the pattern width are compared, and it is checked whether the feature point can be removed. If it can be removed, the processing from step 406 is repeated. If it cannot be removed, it is determined that it cannot be removed by overlapping a predetermined image pattern, and in step 409, the process waits until the feature point passes. The above process is repeated in step 410 until the number of sets of inspection image patterns necessary for the color matching adjustment process is formed.

  As described above, in Embodiment 3 of the present invention, the image forming apparatus stores defect information such as scratches on the intermediate transfer belt as feature points in advance, and forms an inspection image pattern so as to overlap the feature points. In addition, since the feature points are effectively removed by one inspection image pattern, the feature points can be reliably removed, the accuracy of the adjustment process can be improved, and the adjustment process time can be shortened.

  In Embodiment 4 of the present invention, defect information such as scratches on the intermediate transfer belt is stored in advance as feature points, and the feature points are changed by changing the interval between the inspection image patterns so that the inspection image patterns overlap the feature points. Is an image forming apparatus that removes.

  FIG. 7 is a flowchart showing a procedure for forming the inspection image pattern with the interval changed. The basic configuration of the image forming apparatus according to the fourth embodiment is the same as that of the first embodiment. The formation method of the inspection image pattern is different.

  If a plurality of feature points cannot be removed from the inspection image pattern, the processing time may be increased because it is necessary to wait until the feature points pass the transfer position for forming an image on the intermediate transfer member. Therefore, it is determined whether or not feature points can be removed by forming an image pattern in which a predetermined image pattern interval is changed for all feature points included in one set of inspection image patterns, and an image pattern is formed. .

A procedure for forming a predetermined image pattern during the color matching adjustment process will be described with reference to FIG.
In a state where no image is formed on all the photosensitive members 109Bk to 109Y, the rotation of the intermediate transfer belt 105 is started in step 500. In step 501, a reference position of the intermediate transfer belt 105 is detected by a reference position detection sensor (not shown). After detecting the reference position, in step 502, the distance to the next feature point position is compared with the total pattern length to check whether the inspection image pattern can be formed. If the total pattern length is shorter, in step 503, one set of inspection image pattern is formed. If the total pattern length is longer, in step 504, the feature point width is compared with the pattern width to check whether the feature point can be removed. If the pattern width is longer, it is determined that the feature point can be removed by forming a predetermined image pattern on the feature point. If removal is possible, in step 505, priority is given to the color of the image pattern to be overlapped over the color in which the image is formed in order, for example, M>C>Bk> Y.

  Here, assuming that feature point removal has been performed with the image pattern of the determined color, it is checked in step 506 whether the next feature point falls within one set of image patterns. If not, in step 507, an inspection image pattern is formed. If so, in step 508, the feature point width is compared with the pattern width to check whether the feature point can be removed. If it is determined that the feature point can be removed, in step 509, the color determined as the color to be superimposed on the first feature point is changed to the previous color (C if M, Bk if C). In step 510, a predetermined image pattern interval is adjusted so as to overlap the second feature point. If it is determined that the image cannot be removed by superimposing the inspection image patterns, the process waits until the feature point passes in step 511. The above processing is repeated in step 512 until the number of inspection image patterns necessary for the color matching adjustment processing is formed.

  As described above, in the fourth embodiment of the present invention, the image forming apparatus stores defect information such as scratches on the intermediate transfer belt as feature points in advance, and performs inspection so that the inspection image pattern overlaps the feature points. Since the feature points are removed by changing the interval between the image patterns, the feature points can be reliably removed, the accuracy of the adjustment process can be improved, and the adjustment process time can be shortened.

  In Embodiment 5 of the present invention, defect information such as scratches on the intermediate transfer belt is stored in advance as feature points, and the inspection image pattern width is changed so that the inspection image pattern overlaps the feature points. An image forming apparatus that removes dots.

  FIG. 8 is a flowchart showing a procedure for forming an inspection image pattern having a changed width. The basic configuration of the image forming apparatus in the fifth embodiment is the same as that in the first embodiment. The formation method of the inspection image pattern is different.

  When the distance between two feature points is short, if the predetermined image pattern interval is narrowed, the pattern interval becomes too narrow and the pattern may not be recognized normally. Therefore, it is determined whether the feature points can be removed by changing the predetermined image pattern interval or changing the image pattern width for all feature points included in one set of inspection image patterns. Form.

With reference to FIG. 8, a procedure for forming an inspection image pattern during the color matching adjustment process will be described.
In step 600, rotation of the intermediate transfer belt 105 is started in a state where no image is formed on all the photoreceptors 109Bk to 109Y. In step 601, a reference position of the intermediate transfer belt 105 is detected by a reference position detection sensor (not shown). After detecting the reference position, in step 602, the distance to the next feature point position is compared with the total pattern length to check whether the inspection image pattern can be formed. If the total pattern length is shorter, an inspection image pattern can be formed. In step 603, one set of inspection image pattern is formed. If the total pattern length is longer, in step 604, the feature point width is compared with the pattern width to check whether the feature point can be removed.

  If the pattern width is longer, it is determined that the feature point can be removed by forming a predetermined image pattern on the feature point. If possible, in step 605, the color of the image pattern to be overlaid is determined in preference to the color in which the image is formed in order. For example, the order is M> C> Bk> Y. Here, it is assumed that feature point removal has been performed with the image pattern of the determined color, and in step 606, it is checked whether or not the next feature point falls within one set of image patterns. If not, in step 607, an inspection image pattern is formed. If yes, in step 608, the feature point width is compared with the pattern width. If it is determined that the feature point can be removed, it is determined in step 609 whether the feature point can be removed by adjusting a predetermined image pattern interval based on the distance between the first feature point and the second feature point.

  If it is determined that removal is possible, the color determined as the color to be superimposed on the first feature point is changed to the previous color in step 610 (C for M, Bk for B, Bk for C) If yes, no change if Y), in step 611, the interval of the inspection image pattern is adjusted so as to overlap the second feature point. If removal is not possible, in step 612, the width of the inspection image pattern is adjusted so as to overlap the two feature points. If it cannot be removed, it is determined that the removal cannot be performed by superimposing the inspection image patterns, and in step 613, the process waits until the feature point passes. The above processing is repeated in step 614 until the number of inspection image pattern sets necessary for the color matching adjustment processing is formed.

  As described above, in the fifth embodiment of the present invention, the image forming apparatus stores defect information such as scratches on the intermediate transfer belt as feature points in advance, and the inspection image pattern overlaps the feature points. Since the configuration is such that the feature points are removed by changing the width of the inspection image pattern, the feature points can be reliably removed, the accuracy of the adjustment processing can be increased, and the adjustment processing time can be shortened.

  In the sixth embodiment of the present invention, defect information such as scratches on the intermediate transfer belt is stored in advance as feature points, and the inspection image pattern is widened so that the inspection image pattern overlaps the feature points. Is an image forming apparatus that removes.

  FIG. 9 is a flowchart showing a procedure for forming an inspection image pattern having a wide width. The basic configuration of the image forming apparatus in the sixth embodiment is the same as that in the first embodiment. The formation method of the inspection image pattern is different.

  When the feature point width is wider than the inspection image pattern width, feature points cannot be completely removed from the inspection image pattern, and the accuracy of the adjustment process decreases. Therefore, when the feature point width is wider than the pattern width, an image pattern is formed on all the feature points by forming an image pattern in which the pattern width is changed.

With reference to FIG. 9, a procedure for forming an inspection image pattern during the color matching adjustment process will be described.
In step 700, rotation of the intermediate transfer belt 105 is started in a state where no image is formed on all the photosensitive members 109Bk to 109Y. In step 701, a reference position of the intermediate transfer belt 105 is detected by a reference position detection sensor (not shown). After detecting the reference position, in step 702, the distance to the next feature point position is compared with the total pattern length to check whether the inspection image pattern can be formed. Since it is possible if the total pattern length is shorter, one set of inspection image patterns is formed in step 703. If the total pattern length is longer, in step 704, the feature point width is compared with the pattern width to check whether the feature point can be removed.

  If the pattern width is longer, it is determined that the feature point can be removed by forming the inspection image pattern on the feature point. In step 706, an image is formed so that the inspection image pattern overlaps the feature point. At this time, in order to shorten the processing time, in step 705, the color of the image pattern to be overlapped is determined in preference to the color in which the order of image formation is late. For example, the order is M> C> Bk> Y. If the pattern width is shorter, the pattern width is adjusted in step 707 so that it is longer than the feature point width. The above processing is repeated in step 708 until the number of inspection image patterns required for the color matching adjustment processing is formed.

  As described above, in the sixth embodiment of the present invention, the image forming apparatus stores defect information such as scratches on the intermediate transfer belt as feature points in advance, and inspects the inspection image pattern so as to overlap the feature points. Since the feature point is removed by increasing the width of the image pattern, the feature point can be reliably removed, the accuracy of the adjustment process can be improved, and the adjustment process time can be shortened.

  The image forming apparatus of the present invention is most suitable as an electrophotographic copying machine, a printer, a facsimile, or the like.

  104 ... sheet, 105 ... intermediate transfer belt, 106 ... AIO cartridge, 107 ... secondary transfer drive roller, 108 ... transfer belt tension roller, 109 ... photoconductor, 110 ...・ Charger, 111 ... exposure unit, 112 ... developing unit, 113 ... cleaner blade, 114 ... laser beam, 115 ... primary transfer roller, 116 ... secondary transfer roller, 117 ... TM sensor, 200 ... ROM, 201 ... RAM, 202 ... EEPROM, 203 ... Surface information detection sensor, 204 ... primary transfer bias, 205 ... polygon motor, 206 ..Laser, 207 ... development bias, 208 ... intermediate transfer position detection sensor.

Japanese Patent No. 3682905 (Japanese Patent Laid-Open No. 10-115966)

Claims (14)

A latent image carrier, a latent image forming unit for forming a latent image on the latent image carrier, a developing unit for developing the latent image to form a visible image, and an intermediate for transferring the visible image to an intermediate transfer member Transfer means, intermediate transfer position detection means for determining the position of the intermediate transfer member,
Obtained by detecting surface information detection means for detecting surface information on the intermediate transfer body by reflected light irradiating light on the intermediate transfer body, and by detecting feature points on the intermediate transfer body by the surface information detection means In an image forming apparatus comprising a feature point storage unit that stores feature point information, an inspection image pattern forming unit that forms an inspection image pattern for determining the position of the intermediate transfer member on the intermediate transfer position detection unit; And determining whether or not the feature point can be effectively removed by forming the inspection image pattern on the feature point so that the feature point cannot be detected by the surface information detecting means. And a formation control means for controlling the formation timing so as to form the inspection image pattern and remove the feature points when it is determined that they can be effectively removed. Image forming apparatus characterized by.   The inspection image pattern forming means includes means for forming the inspection image pattern in a plurality of colors, and the feature point removal determination means determines a color that can most effectively remove the feature points based on the feature point information. The image forming apparatus according to claim 1, further comprising:   The feature point removal determining means includes means for determining that the intermediate transfer member is unusable when the feature point cannot be removed even with a color that can most effectively remove the feature point. The image forming apparatus according to claim 2.   The feature point removal determination means includes means for determining whether or not a plurality of feature points can be removed with one inspection image pattern, and the formation control means determines that all feature points are determined according to the determination that the feature points can be removed. 2. The apparatus according to claim 1, further comprising: means for controlling the inspection image patterns to overlap, and means for forming the inspection image pattern so as to avoid all feature points in accordance with the determination that the inspection image patterns cannot be removed. The image forming apparatus described in 1.   Means for controlling the formation control means to form the inspection image pattern on all the feature points by changing the interval of the inspection image pattern so as to overlap all the feature points in accordance with the determination that it can be removed. The image forming apparatus according to claim 4, further comprising:   The feature point removal determination means includes means for determining whether or not the distance between the feature points is removable to a certain extent, and the formation control means is responsive to the determination that the distance can be removed to a certain extent. 6. The image forming apparatus according to claim 5, further comprising means for controlling the inspection image pattern to be formed on all feature points by increasing the width of the inspection image pattern.   The feature point removal determining means includes means for determining whether or not the distance between the feature points is longer than the width of the inspection image pattern but can be removed, and the formation control means removes the feature point removal determination means. Characterized in that it comprises means for widening the inspection image pattern in response to a determination that the inspection image pattern is possible and having a certain length and controlling the inspection image pattern to be formed on all feature points. The image forming apparatus according to claim 1.   A latent image is formed on the latent image carrier, the latent image is developed to form a visible image, the position of the intermediate transfer member is determined, the visible image is transferred to the intermediate transfer member, and the visible image is transferred. In the image forming method for transferring from the intermediate transfer member to the printing paper, surface information on the intermediate transfer member is detected by reflected light that is irradiated onto the intermediate transfer member, and feature points on the intermediate transfer member are detected. Information is acquired and stored, and an inspection image pattern for determining the position of the intermediate transfer member is formed on the feature point, so that the feature point cannot be detected by the surface information detection means. The inspection image pattern on the feature point is controlled by controlling the formation timing so as to remove the feature point when it is determined that the feature point can be effectively removed. It is characterized by forming into An image forming method.   9. The image forming method according to claim 8, wherein a color that can most effectively remove the feature point is determined based on the feature point information, and the inspection image pattern is formed with a plurality of colors.   10. The intermediate transfer member is determined to be unusable when the feature point cannot be effectively removed even with a color that can most effectively remove the feature point. Image forming method.   It is determined whether or not a plurality of feature points can be removed with one inspection image pattern, and the inspection image pattern is formed on all the feature points in accordance with the determination that they can be removed. 9. The image forming method according to claim 8, wherein the inspection image pattern is formed so as to avoid all feature points accordingly.   12. The inspection image pattern is formed on all feature points by changing the interval of the inspection image patterns so as to overlap all feature points in accordance with the determination that removal is possible. The image forming method described.   It is determined whether or not the distance between the feature points is short enough to effectively remove the feature points. 13. The image forming method according to claim 12, wherein the inspection image pattern is formed on all feature points. Although the distance between the feature points is longer than the width of the inspection image pattern, it is determined whether the feature points are long enough to be effectively removed, and are long enough to be removed. 9. The image forming method according to claim 8, wherein the inspection image pattern is formed on all feature points by widening the inspection image pattern according to the determination.

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