JP5375361B2 - Image forming apparatus, image forming system, and processing program - Google Patents

Description

  The present invention relates to an image forming apparatus, an image forming system, and a processing program.

  Conventionally, in an image forming apparatus such as a color laser printer, a patch image as a position detection index is formed on an image carrier, and this patch image is read by an optical sensor.

  In the control for detecting the amount of deviation from the result of reading by the optical sensor, the amount of deviation is detected by a relative distance with respect to a predetermined reference color, and color matching adjustment is performed.

  Various techniques related to an image forming apparatus that performs such color matching adjustment have been proposed.

  For example, Japanese Patent Laid-Open No. 2002-23445 discloses a plurality of image forming units that form images of different colors, and a movement that moves to transfer images formed by the plurality of image forming units at a transfer position, respectively. A plurality of images in a direction intersecting the moving direction of the moving body so that a pattern image of one other color is transferred onto the moving body between the body and two pattern images of a predetermined reference color. A pattern forming unit that controls the plurality of image forming units to form a pattern image; a pattern detecting unit that detects the pattern image transferred onto the movable body; and the reference based on an output of the detecting unit. An image shape including a correcting unit that detects a positional deviation amount of an image of another color with respect to a color image and corrects a positional deviation of the image of the other color based on the detected positional deviation amount. Apparatus is disclosed.

JP 2002-23445 A

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus, an image forming system, and a processing program that can improve the accuracy of correction of misregistration of each color image.

In order to solve the above-described problem, an image forming apparatus according to a first aspect of the present invention includes a plurality of image forming units that form images having different colors and images having different colors that are formed by the plurality of image forming units. A holding means for holding the image; a transfer means for transferring images of different colors held on the holding means onto a recording medium; and an index for forming a position detection index on the holding means using the image forming means. Forming means, detecting means for detecting an interval between the position detecting indices formed by the index forming means, and position detecting corresponding to each color when each color is set as a reference color based on the detection result of the detecting means Calculation means for calculating a positional deviation amount between an index and a position detection index corresponding to another color, storage means for storing history information of a calculation result by the calculation means, and history stored in the storage means Based on the distribution, and changing means for a reference color of the absolute value the position detection index the least color the maximum value of the sum of the positional shift amount calculated by the calculation means, the other colors with respect to the reference color Correction means for correcting a position shift of an image of another color based on a relative position shift amount.

According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, when the changing unit replaces the image forming unit that forms an image of the reference color of the position detection index , The reference color of the index for position detection is changed to a color corresponding to any one of the colors corresponding to the other image forming units not exchanged.

According to a third aspect of the present invention, there is provided an image forming apparatus according to the first or second aspect , wherein the position detecting index by the changing unit is changed according to a change in an environment in which the image forming unit performs image formation. The apparatus further comprises first adjusting means for adjusting a time interval for changing the reference color.

An image forming apparatus according to a fourth aspect of the invention is characterized in that, in the invention according to the third aspect , the environment in which the image is formed includes a temperature environment and a humidity environment.

According to a fifth aspect of the present invention, in the image forming apparatus according to any one of the first to fourth aspects, the position detection by the changing unit is performed according to the number of times of image formation by the image forming unit. The apparatus further comprises second adjusting means for adjusting a time interval for changing the reference color of the index for use.

According to a sixth aspect of the present invention, in the image forming apparatus according to any one of the first to fifth aspects, a maximum value of the positional deviation amount is preset in the history information stored in the storage means. If the threshold value is greater than or equal to the threshold value, after performing the first adjustment process for adjusting the formation position of the position detection index, the second adjustment process with a smaller amount of position adjustment than the first adjustment process is executed. Further, it is characterized by further comprising control means for performing control so that only the second adjustment processing is executed when the maximum value of the positional deviation amount is not more than the threshold value.

An image forming system according to a seventh aspect of the present invention includes at least one image forming apparatus according to any one of the first to sixth aspects, and one or more connected to the image forming apparatus via a communication unit. And an information processing apparatus.

According to an eighth aspect of the present invention, there is provided a processing program for forming an image having different colors, a holding process for holding images having different colors formed in the image forming process, and holding each other. Based on the detection result, the transfer process for transferring images of different colors onto the recording medium, the formation process for forming the position detection index, the detection process for detecting the interval between the formed position detection indices, and the detection result. A calculation process for calculating a positional deviation amount between a position detection index corresponding to each color in the case of the reference color and a position detection index corresponding to another color, a storage process for storing history information of a calculation result, Based on the stored history information, a change process in which a color having the smallest total sum of absolute values of the positional deviation amounts calculated in the calculation process is set as a reference color of the position detection index; and the reference color In To other based on the relative positional deviation amount of the color, characterized in that to execute a correction process for correcting the positional deviation of other colors in the image, to the arithmetic means.

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

  That is, according to the first aspect of the present invention, it is possible to provide an image forming apparatus capable of improving the accuracy of the positional deviation correction of each color image.

According to the second aspect of the present invention, it is possible to provide an image forming apparatus capable of improving the accuracy of the positional deviation correction of each color image.

According to the third aspect of the present invention, it is possible to provide an image forming apparatus that can further improve the accuracy of the positional deviation correction of each color image.

According to the invention described in claim 4 , it is possible to provide an image forming apparatus capable of further improving the accuracy of the positional deviation correction of each color image.

According to the fifth aspect of the present invention, it is possible to provide an image forming apparatus capable of maintaining good print quality.

According to the sixth aspect of the present invention, it is possible to provide an image forming apparatus capable of shortening the time required for correcting the positional deviation of each color image.

According to the seventh aspect of the present invention, it is possible to provide an image forming system capable of improving the accuracy of positional deviation correction of each color image.

According to the eighth aspect of the present invention, it is possible to provide a processing program capable of improving the accuracy of positional deviation correction of each color image.

1 is a schematic configuration diagram illustrating a configuration of an image forming apparatus PR1 according to a first embodiment. 2 is a functional block diagram showing a functional configuration of an image forming apparatus PR1 according to the first embodiment. FIG. It is explanatory drawing which shows the example of formation of the pattern P for position detection. It is explanatory drawing which shows the example of a detection of the space | interval of the position detection pattern P. FIG. It is a flowchart which shows the process sequence of a reference | standard color change process. It is a table | surface which shows the example of the calculation result of positional offset amount. It is a flowchart which shows the process sequence of a reference | standard color change process. It is a table | surface which shows the example of the calculation result of positional offset amount. It is a table | surface which shows the example of the calculation result of positional offset amount. It is a table | surface which shows the example of the calculation result of positional offset amount. It is a table | surface which shows the example of the calculation result of positional offset amount. It is a flowchart which shows the process sequence of a reference | standard color change process. FIG. 6 is a functional block diagram illustrating a functional configuration of an image forming apparatus PR2 according to a second embodiment. It is a flowchart which shows the process sequence of a reference | standard color change process. It is a flowchart which shows the process sequence of a color matching process. FIG. 10 is a functional block diagram illustrating a functional configuration of an image forming apparatus PR3 according to a third embodiment. It is a flowchart which shows the process sequence of a position adjustment amount control process.

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

  (First embodiment)

  An image forming apparatus PR1 according to the first embodiment of the present invention will be described with reference to FIGS.

  In addition, about the structure etc. which are not directly related to this invention, it abbreviate | omits.

  As shown in FIGS. 1 and 2, a full-color printer PR1 as an example of an image forming apparatus according to the present embodiment forms a plurality of images having different colors, and holds a plurality of formed images having different colors. (Four in this embodiment) image forming units (drum cartridges) 10 (10Y, 10M, 10C, 10K) (an example of image forming means and holding means) and image forming units 10 (10Y, 10M, 10C, 10K), a transfer belt 20 (an example of a transfer unit) as an intermediate transfer member that transfers images of different colors held on a printing paper (an example of a recording medium), and an image forming unit 10 (10Y, 10M, 10C, 10K), a position detection pattern forming unit 30 (index shape) for forming a position detection index (position detection pattern) on the photosensitive drum. Based on the detection result of the pattern detection sensor 40 (an example of the detection means) and the pattern detection sensor 40 (an example of the detection means) for detecting the interval between the position detection patterns formed by the position detection pattern forming unit 30. A calculation unit 50 (comprising a microcomputer (or a CPU in a broad sense) that calculates a positional deviation amount between a position detection pattern corresponding to a preset reference color and a position detection pattern corresponding to another color) An example of a calculation unit), a nonvolatile memory 60 (an example of a storage unit) that stores history information of a calculation result by the calculation unit, and a position detection pattern based on the history information stored in the nonvolatile memory 60 A reference color changing unit 70 (an example of a changing unit) that changes the reference color, and a positional deviation of an image of another color based on a relative positional deviation amount of the other color with respect to the reference color And a (an example of a correction means) positional deviation correcting unit 80 for correcting.

  Also, in the vicinity of each image forming unit 10 (10Y, 10M, 10C, 10K), an attachment / detachment detection sensor 15 (15Y, 15M, 15C, 15K) for detecting attachment / detachment due to replacement work of the unit itself is provided.

  The main body side control board 100 including the microcomputer (CPU in a broad sense) includes a nonvolatile memory 60, a detection circuit 51 that performs detection processing by the pattern detection sensor 40, a ROM that stores a predetermined program, a work area, and the like. A RAM 53 or the like used as the above may be mounted (see FIG. 1).

  The image forming unit 10 (10Y, 10M, 10C, 10K) is provided with an exposure device 11 that irradiates a laser beam to form a latent image of an image or a position detection pattern.

  Here, with reference to FIG. 3, the formation state and the like of the position detection patterns P (P1 to P4) will be described.

  In the example shown in FIG. 3, a position detection pattern P is formed at a substantially central portion of the transfer belt 20. The position where the position detection pattern P is formed is not limited to the center portion, and may be formed at the end portion of the transfer belt 20 or the like.

  The arrangement of the position detection pattern P is not particularly limited, but an example is shown in FIG. 3 (before change).

  In the example (before change) shown in FIG. 3, the reference color is assumed to be black (K).

  Then, the position detection patterns P1a, P1b, P1c, and P1d are formed with the reference color black, and the position detection pattern formed in cyan (C) between the position detection patterns P1a, P1b, P1c, and P1d. A pattern P2, a position detection pattern P3 formed in magenta (M), and a position detection pattern P4 formed in yellow (Y) are formed.

  The position detection pattern P formed in this way is read by the pattern detection sensor 40 constituted by, for example, a visible light regular reflection photosensor, and the interval between the position detection patterns is detected.

  The method of detecting the interval between the position detection patterns is not particularly limited, but is detected as shown in FIG. 4, for example.

  In the example shown in FIG. 4, the pattern detection sensor 40 detects a pattern image of the position detection pattern P formed on the transfer belt 20, and the detection signal is converted into a binary pulse by a comparator. Measurement is performed using the input capture function, and the amount of positional deviation with respect to a preset reference color (in this embodiment, black) position detection patterns P1a, P1b, P1c, and P1d is calculated.

  Then, based on the calculated misregistration amount, the reference color is changed by processing of the reference color changing unit 70 (detailed processing procedure will be described later).

  The example after the change shown in FIG. 3 shows a case where the reference color is changed from black to cyan.

  In the example after the change, position detection patterns P2a, P2b, P2c, and P2d are formed with the reference color cyan, and black (K) is formed between the position detection patterns P2a, P2b, P2c, and P2d. The position detection pattern P1, the position detection pattern P3 formed in magenta (M), and the position detection pattern P4 formed in yellow (Y) are formed.

  As a result, since the color with a small amount of variation is used as a reference, the accuracy of positional deviation correction of the image of each color is improved.

  Next, an example of the processing procedure of the reference color changing process executed by the image forming apparatus PR1 will be described with reference to the flowchart of FIG.

  When this process is started, first, the stored value relating to the positional deviation amount history stored in the nonvolatile memory 60 and the storage counter for the positional deviation amount are cleared in step S10, and the process proceeds to step S11.

  In step S11, it is determined whether or not the color matching execution condition is satisfied. If “No”, the process waits. If “Yes”, the process proceeds to step S12.

  In step S12, the position detection pattern P is drawn (formed), the process proceeds to step S13, and the pattern detection process is started.

  Next, when the position detection pattern P is detected in step S14, the process proceeds to step S15 to determine whether or not the detection of all the position detection patterns P is completed. Returning to step S16, the process proceeds to step S16 if "Yes".

  In step S16, the amount of misregistration with respect to the reference color is calculated and the process proceeds to step S17. The amount of misregistration is stored in the nonvolatile memory 60, and the process proceeds to step S18.

  In step S18, the misregistration amount storage counter is incremented by "1" and the process proceeds to step S19.

  In step S19, it is determined whether or not the misregistration amount storage counter has reached 10. If “No”, the process returns to step S11, and if “Yes”, the process proceeds to step S20.

  In step S20, the maximum / minimum difference of each color is calculated, and the process proceeds to step S21.

  In step S21, the reference color changing unit 70 changes the reference color to the color having the smallest difference, and the process proceeds to step S22.

  For example, as shown in FIG. 6, when the maximum and minimum differences in the positional deviation amounts for yellow (Y), magenta (M), and cyan (C) are +20 μm, +30 μm, and +50 μm, The yellow color (Y) having the smallest difference is determined as the most stable color, and the reference color is changed to the yellow color (Y).

  In step S22, the stored value of the misregistration amount in the nonvolatile memory 60 and the storage counter are cleared, and the process returns to step S11.

  As a result, since the color with a small amount of variation is used as a reference, the accuracy of positional deviation correction of the image of each color is improved.

  Next, another example of the processing procedure of the reference color changing process executed by the image forming apparatus PR1 will be described with reference to the flowchart of FIG.

  When this process is started, first, the stored value related to the misregistration amount history stored in the non-volatile memory 60 and the misregistration amount storage counter are cleared in step S30, and the process proceeds to step S31.

  In step S31, it is determined whether or not the color matching execution condition is satisfied. If “No”, the process waits, and if “Yes”, the process proceeds to step S32.

  In step S32, the position detection pattern P is drawn (formed), the process proceeds to step S33, and the pattern detection process is started.

  Next, when the position detection pattern P is detected in step S34, the process proceeds to step S35, where it is determined whether or not the detection of all the position detection patterns P is completed. If “No”, the process proceeds to step S34. Returning to step S36, the process proceeds to step S36 if "Yes".

  In step S36, the amount of positional deviation with respect to the reference color is calculated and the process proceeds to step S37. The amount of positional deviation is stored in the nonvolatile memory 60, and the process proceeds to step S38.

  In step S38, the misregistration amount storage counter is incremented by "1" and the process proceeds to step S39.

  In step S19, it is determined whether or not the misregistration amount storage counter has reached 10. If “No”, the process returns to step S31, and if “Yes”, the process proceeds to step S40.

  In step S40, the amount of displacement when each color is used as a reference color is calculated, and the process proceeds to step S41.

  In step 41, the reference color is changed by the reference color changing unit 70 to the color having the smallest total sum of the absolute values of the displacement amounts, and the process proceeds to step S42.

  For example, based on the detection results as shown in FIG. 8 to FIG. 11, the deviation amount when the other color is set as the reference color is calculated from the displacement amount of black (K), and the absolute value of the deviation amount of each color is calculated. The maximum value of the total amount of misregistration of each color when yellow (Y) is used as a reference color is 940 μm, and the misregistration amount is the smallest when other colors are used as reference colors. In this example, the reference color is changed to yellow (Y).

  In step S42, the stored value and the storage counter in the non-volatile memory 60 of the positional deviation amount are cleared, and the process returns to step S11.

  As a result, since the color with a small amount of variation is used as a reference, the accuracy of positional deviation correction of the image of each color is improved.

  Next, another example of the processing procedure of the reference color changing process executed by the image forming apparatus PR1 will be described with reference to the flowchart of FIG.

  This example is an example of the reference color changing process when any of the image forming units 10 (10Y, 10M, 10C, 10K) is replaced.

  In step S50, it is determined whether any of the image forming units 10 (10Y, 10M, 10C, 10K) has been replaced based on the detection result of the attachment / detachment detection sensor 15 (15Y, 15M, 15C, 15K).

  If the determination result is “No”, the process waits, and if “Yes”, the process proceeds to step S51.

  In step S51, it is determined whether or not the replaced image forming unit 10 is of the reference color. If “No”, the process proceeds to step S54 to end the process without changing the reference color. To do.

  On the other hand, in the case of “Yes”, the process proceeds to step S52, the maximum / minimum difference of the positional deviation amounts of the respective colors is calculated, and the process proceeds to step S53.

  In step S53, the reference color is changed to a color having the smallest difference, and the process is terminated.

  As a result, since the color for which the image forming unit is not exchanged is not greatly displaced, the positional deviation with respect to the printing paper is suppressed, and the same print quality as before the exchange is maintained even immediately after the image forming unit is exchanged.

  In addition, as a mode of changing the reference color by the reference color changing unit 70, in addition to the case described above, in the history information stored in the nonvolatile memory 60, the positional deviation amount exceeds a preset threshold value. A mode in which the reference color is changed, a mode in which the reference color is changed to a color having the smallest average value of the positional deviation amount, a mode in which the reference color is changed to a color having the smallest deviation value in the positional deviation amount, and the like are employed.

  (Second Embodiment)

  An image forming apparatus PR2 according to the second embodiment of the present invention will be described with reference to FIGS.

  In addition, about the structure similar to image forming apparatus PR1 which concerns on 1st Embodiment, the same code | symbol is attached | subjected and the overlapping description is omitted.

  The overall configuration of the image forming apparatus PR2 is as shown in FIG.

  The image forming apparatus PR2 according to the second embodiment is different from the image forming apparatus PR1 according to the first embodiment in that the image forming unit 10 (10Y, 10M) is shown in the functional block diagram of FIG. 10C, 10K), the temperature sensor 91 and the humidity sensor 92 that detect changes in the environment in which image formation is performed, and the position detection pattern P by the reference color changing unit 70 according to the detection results of the temperature sensor 91 and the humidity sensor 92. An image was formed by the first time interval adjustment unit 90 (an example of the first adjustment unit) that adjusts the time interval for changing the reference color and the image forming unit 10 (10Y, 10M, 10C, 10K). An image forming number counting unit 111 that counts the number of times, and a time period during which the reference color changing unit 70 changes the reference color of the position detection pattern P according to the number of image forming times In that a second time interval adjustment unit 110 that adjusts (an example of a second adjustment means) to be.

  As a result, the accuracy of the positional deviation correction of the image of each color is improved.

  Here, with reference to the flowcharts of FIG. 14 and FIG. 15, the processing procedure of the reference color changing process executed in the image forming apparatus PR2 will be described.

  When the reference color changing process shown in FIG. 14 is started, an initialization operation necessary for the printing operation is performed in step S60. Next, the print request is confirmed in step S61.

  On the other hand, if “Yes”, the process proceeds to an image output process.

  In step S62, the color matching request is confirmed, and if “Yes” (when there is a color matching request), the process proceeds to a color matching processing subroutine in step S63 (detailed processing procedure will be described later). .

  On the other hand, in the case of “No” (when there is no color matching request), the process proceeds to the image forming process in step S64.

  The image forming process in step S64 is executed by a cycle of charging, exposure, development, transfer, fixing, and cleaning (electrophotographic technology) to realize one-sheet printing.

  After printing one sheet, color matching is confirmed in step S65.

  In this example, the condition at that time is a temperature change and a predetermined number of printed sheets.

  The temperature change condition refers to a case where the temperature sensor 91 changes the temperature of the color matching by a predetermined value (for example, 3 ° C.).

  In addition, the condition for the passage of a predetermined number of printed sheets is counted up as 1 PV when printing in A4 size (whether monochrome or color). This means that the counter has passed a predetermined value (for example, 200 PV).

  In addition to the temperature change, the humidity measured by the humidity sensor 92 may be used as a condition for color matching. Further, the number of image formations may be used as a condition for color matching instead of the number of printed sheets.

  If the conditions match, the process proceeds to step S66, the color matching request flag is set, and the process returns to step S61.

  On the other hand, if the conditions do not match, the process returns to step S61.

  Next, the procedure of the color matching process described above will be described with reference to the flowchart of FIG.

  In the color matching process, first, a sub-scanning position detection pattern P is output on the transfer belt 20 in step S631.

  The position detection pattern P is formed, for example, in a pattern as shown in FIG.

  The formed pattern P for position detection is read by the pattern detection sensor 40 (S632).

  The pattern detection sensor 40 is, for example, for measuring toner on the transfer belt 20 and includes an LED light emitting element and a light receiving element. The LED light is captured by the pattern detection sensor 40 as light reflected from the belt.

  Based on the acquired sensor data, the amount of positional deviation is calculated (S633).

  Similar processing is performed in the main scanning direction. That is, a position detection pattern for main scanning is output (S634).

  The pattern detection sensor 40 is read (S635), and the amount of displacement is calculated (S636).

  Next, feedback of the image writing position is performed (S637).

  After the color matching adjustment, a determination is made to determine a threshold value for the next color matching interval (S638).

  When the positional deviation amount is within the predetermined value (“Yes” in S638), the temperature change amount and the threshold value for the predetermined number of printed sheets are changed to values that extend (S639).

  On the other hand, when the positional deviation amount exceeds the predetermined value (“No” in S638), the temperature change amount and the threshold value for the predetermined number of printed sheets are changed to default values, and then the main process of FIG. Return (S640).

  Accordingly, in consideration of the material and the like of the image forming apparatus, calibration is suppressed by a simple method, and user convenience is improved by improving the through-up.

  (Third embodiment)

  With reference to FIG. 16, an image forming apparatus PR3 according to a third embodiment of the present invention will be described.

  In addition, about the structure similar to image forming apparatus PR1 which concerns on 1st Embodiment, the same code | symbol is attached | subjected and the overlapping description is omitted.

  The overall configuration of the image forming apparatus PR3 is as shown in FIG.

  The image forming apparatus PR3 according to the third embodiment is different from the image forming apparatus PR1 according to the first embodiment in that it is stored in the nonvolatile memory 60 as shown in the functional block diagram of FIG. If the maximum value of the positional deviation amount is equal to or larger than a preset threshold value in the history information, the first adjustment process (coarse adjustment) for adjusting the position where the position detection pattern P is formed is performed, and then the first The second adjustment process (fine adjustment) having a smaller position adjustment amount than the adjustment process is executed, and when the maximum value of the positional deviation amount is equal to or smaller than the threshold value, control is performed so that only the second adjustment process is executed. It is a point provided with the position adjustment amount control part 120 (an example of a control means).

  As a result, the time required for correcting the misregistration of the images of the respective colors is shortened, and the user convenience is improved.

  Here, with reference to the flowchart of FIG. 17, a processing procedure of the position adjustment amount control process executed in the image forming apparatus PR3 will be described.

  When this process is started, first, the stored value related to the misregistration amount history stored in the non-volatile memory 60 and the misregistration amount storage counter are cleared in step S70, and the process proceeds to step S71.

  In step S71, it is determined whether or not the color matching execution condition is met. If “No”, the process waits, and if “Yes”, the process proceeds to step S72.

  In step S72, the position detection pattern P is drawn (formed), the process proceeds to step S73, and the pattern detection process is started.

  Next, when the position detection pattern P is detected in step S74, the process proceeds to step S75, and it is determined whether or not the detection of all the position detection patterns P is completed. If “No”, the process proceeds to step S74. Returning to step S <b> 76, the process proceeds to step S <b> 76.

  In step S76, the amount of positional deviation with respect to the reference color is calculated and the process proceeds to step S77. The amount of positional deviation is stored in the nonvolatile memory 60, and the process proceeds to step S78.

  In step S78, the misregistration amount storage counter is incremented by "1" and the process proceeds to step S79.

  In step S79, it is determined whether or not the misregistration amount storage counter has reached 10. If “No”, the process returns to step S71, and if “Yes”, the process proceeds to step S80.

  In step S80, the amount of positional deviation when each color is used as a reference color is calculated, and the process proceeds to step S81.

  In step 81, the reference color is changed by the reference color changing unit 70 to a color having the smallest total sum of the absolute values of the displacement amounts, and the process proceeds to step S82.

  In step S82, it is determined whether or not the maximum deviation amount is less than a threshold value (for example, 200 μm). If “No”, the process proceeds to step S85, and in the next color matching adjustment, the first adjustment processing (roughness) is performed. Adjustment: For example, position adjustment of 200 μm or less is performed, and second adjustment processing (fine adjustment: position adjustment of, for example, about ± 10 μm) is performed, and then the process proceeds to step S84 to shift the position The stored value and the storage counter in the non-volatile memory 60 are cleared, and the process returns to step S71.

  On the other hand, if “Yes” in the step S82, the process proceeds to a step S83, and only the second adjustment process (fine adjustment: for example, position adjustment of about ± 10 μm) is performed in the next color matching adjustment. Then, the process proceeds to step S84, where the stored value and the storage counter in the nonvolatile memory 60 of the positional deviation amount are cleared and the process returns to step S71.

  As a result, the frequency of performing only fine adjustment increases, the time required for color matching processing is shortened, and the convenience for the user is improved.

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

  For example, it is also conceivable to print out the position detection pattern on a recording medium such as printing paper and detect the interval between the position detection patterns.

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

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

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

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

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

  The image forming apparatus, the image forming system, and the processing program according to the present invention can be applied to a full-color printer, a multifunction machine, and the like.

PR1, PR2, PR3 Image forming apparatus 10 Image forming unit 11 Exposure apparatus 15 Attachment / detachment detection sensor 20 Transfer belt 30 Position detection pattern forming section 40 Pattern detection sensor 50 Calculation section 51 Detection circuit 60 Non-volatile memory 70 Reference color changing section 80 Correction Unit 90 time interval adjustment unit 91 temperature sensor 92 humidity sensor 100 main body side control board 110 time interval adjustment unit 111 image formation number counting unit 120 position adjustment amount control unit P position detection pattern

Claims (8)

A plurality of image forming means for forming images of different colors;
Holding means for holding images of different colors respectively formed by the plurality of image forming means;
Transfer means for transferring images of different colors held on the holding means onto a recording medium;
Index forming means for forming a position detection index on the holding means using the image forming means;
Detecting means for detecting an interval between the position detecting indices formed by the index forming means;
Based on the detection result of the detection means, a calculation means for calculating a positional deviation amount between a position detection index corresponding to each color and a position detection index corresponding to another color when each color is a reference color;
Storage means for storing history information of calculation results by the calculation means;
Change means for setting a color having the smallest total sum of the absolute values of the positional deviation amounts calculated by the calculation means as a reference color of the position detection index based on the history information stored in the storage means; ,
Correction means for correcting a positional shift of an image of another color based on a relative positional shift amount of the other color with respect to the reference color;
An image forming apparatus comprising: The changing means is
When the image forming unit that forms the image of the reference color of the position detection index is replaced, the position detection is performed on a color corresponding to one of the colors corresponding to the other image forming units that are not replaced. The image forming apparatus according to claim 1, wherein the reference color of the index for use is changed.   The apparatus further comprises a first adjusting unit that adjusts a time interval for changing the reference color of the position detection index by the changing unit according to a change in an environment in which the image forming unit performs image formation. The image forming apparatus according to claim 1.   The image forming apparatus according to claim 3, wherein the image forming environment includes a temperature environment and a humidity environment.   The apparatus further comprises a second adjusting unit that adjusts a time interval for changing the reference color of the position detection index by the changing unit according to the number of times the image forming unit performs image forming. The image forming apparatus according to claim 1.   In the history information stored in the storage means, when the maximum value of the positional deviation amount is equal to or larger than a preset threshold value, after executing the first adjustment process for adjusting the formation position of the position detection index The second adjustment process having a smaller position adjustment amount than the first adjustment process is executed, and when the maximum value of the positional deviation amount is equal to or less than the threshold value, only the second adjustment process is executed. 6. The image forming apparatus according to claim 1, further comprising a control unit that controls the image forming apparatus. At least one image forming apparatus according to any one of claims 1 to 6;
One or more information processing apparatuses connected to the image forming apparatus via a communication unit;
An image forming system comprising: An image forming process for forming images of different colors;
A holding process for holding images of different colors formed in the image forming process;
A transfer process for transferring images of different colors held on a recording medium;
A formation process for forming a position detection index;
A detection process for detecting the interval between the formed position detection indices;
Based on the detection result, a calculation process for calculating a positional deviation amount between a position detection index corresponding to each color and a position detection index corresponding to another color when each color is set as a reference color;
A storage process for storing history information of calculation results;
Based on the stored history information, a changing process in which the color having the smallest total sum of the absolute values of the positional deviation amounts calculated in the calculating process is the reference color of the position detection index;
A correction process for correcting a positional shift of an image of another color based on a relative positional shift amount of the other color with respect to the reference color;
A processing program characterized by causing an arithmetic means to execute.

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