JP2005266246A - Image forming apparatus, control method thereof, program, recording medium with program recorded thereon, and process cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus, control method thereof, program, recording medium with the program recorded thereon, and a process cartridge with which image formation is performed using a single color and a plurality of colors other than an uncorrectable color by performing correction on colors other than an undetectable color if an image position deviation correcting pattern can not be detected. <P>SOLUTION: An image of an image position deviation correcting pattern is formed on a transfer belt 210, and the image position deviation correcting pattern is detected by sensors A, B. If it can be detected, correction data are calculated to perform correction. If it can not be detected, impossibility of correction is notified and an output of a full color image is stopped. With respect to monochromatic and mono-color outputs, however, there is no problem even if position deviation occurs, and thus outputting can be performed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a facsimile machine, and a printer, and more particularly to an image forming apparatus that forms a color image including a full color image by using a plurality of image carriers for each color by an electrophotographic method. .

  In a color image forming apparatus that forms a multi-color image, different from a black and white image, the images of each color are overlapped. Therefore, if the image position of each color is shifted, the color of line drawings and characters may change, or image unevenness (color unevenness). ) Will occur, leading to a reduction in image quality. Therefore, it is necessary to match the image positions of the respective colors.

  For this reason, in an image forming apparatus that forms a color image using a plurality of photoconductors, images generated due to various factors such as machine assembly errors, component accuracy, changes in environmental temperature, and changes in machine temperature. An image forming apparatus having a means for correcting the deviation is described in Japanese Patent Application Laid-Open No. 11-119504 (hereinafter referred to as Patent Document 1) and Japanese Patent Application Laid-Open No. 2000-155453 (hereinafter referred to as Patent Document 2). .

  The image forming apparatus described in Patent Document 1 includes an image misregistration detection unit that detects image misregistration between colors, and manually corrects the image forming position for one image among a plurality of images. The image forming position is automatically corrected for other images based on the output signal from the image position deviation detecting means. As a result, not only the assembly error of the machine and the component accuracy, but also the misregistration can be corrected by the environmental change and the change with time, and a high-quality image without color misregistration can be obtained.

Further, in the image forming apparatus described in Patent Document 2, when performing monochromatic image formation, the processing time for monochromatic output is shortened by not performing image misregistration correction.
JP-A-11-119504 JP 2000-155453 A

However, the image forming apparatuses disclosed in Patent Document 1 and Patent Document 2 described above have the following problems.
In the image forming apparatus described in Patent Document 1, a pattern for correcting misregistration is formed on a transfer belt, detected by a sensor, the misregistration amount is measured based on a signal from the sensor, and fed back to a correction unit. In the case of a system that corrects misregistration, the image density of the misregistration correction pattern needs to be at a level that can be detected by the sensor. If the image is faint, it cannot be accurately detected by the sensor, and naturally, the positional deviation cannot be corrected, and the image quality deteriorates.
Further, in the case of a color image, the image quality is deteriorated due to the image position shift, but this is not a problem in the case of a monochromatic image. For example, if it is impossible to correct misalignment and the image quality deteriorates significantly, inspection and repair are required. However, if the service is not affected, it will not affect the output of a monochrome image. Is preferred.

  Furthermore, in the image forming apparatus described in Patent Document 2, image misregistration correction is not performed when monochromatic image formation is performed. However, this is only for image misregistration correction in a monochromatic image. This is because even if it is not performed, the image is not affected, thereby shortening the processing time for monochrome output. Image position correction is performed only at the time of color output. However, if the correction cannot be performed, the image quality deteriorates, and if the machine is stopped, a monochrome image cannot be output.

  The present invention has been made in view of such problems, and when an image misregistration correction pattern cannot be detected, correction is performed for colors other than those that cannot be detected, and a single color and a plurality of colors that do not use uncorrectable colors are used. It is an object of the present invention to provide an image forming apparatus that performs image formation, a control method for the apparatus, a program, a recording medium that records the program, and a process cartridge.

  In order to achieve the above object, the image forming apparatus according to claim 1 includes means for forming an image of a single color image for each color at least for two colors, and superimposing at least two colors for a single color image to form a multicolor image. An image forming apparatus for forming an image, comprising: a pattern forming unit that forms an image misregistration correction pattern; a detection unit that detects a position of an image misregistration correction pattern formed by the pattern forming unit; and the detection unit Correction means provided for each color for correcting the image position deviation based on the detection result by the above, and a notification means for notifying the correction result, and when the image position deviation cannot be detected by the detection means, single color printing is possible, A notification means notifies that correction is impossible.

  The image forming apparatus according to claim 2 forms a latent image by irradiating image light corresponding to image data on a rotating or moving image carrier, and visualizes the latent image with a developing unit. The visualized image is transferred onto a recording medium conveyed by a rotating or moving transfer unit, or transferred to a rotating or moving transfer unit, and the image transferred to the transferring unit is transferred onto the recording medium. A plurality of image forming units that form a single color image on a recording medium by transferring to the recording medium, and a multicolor image is formed on the recording medium by superimposing the images formed by at least two image forming units on the recording medium An image forming apparatus configured to form a pattern forming unit that forms an image misregistration correction pattern, and a position of the image misregistration correction pattern formed by the pattern forming unit. Detection means for detecting the image, correction means provided for each color to correct the image position deviation based on the detection result by the detection means, and notification means for notifying the correction result, the image position deviation detection means cannot be detected When a color occurs, only the correctable color is corrected, and it is possible to print a single color and a combination of multiple colors that do not use a color that cannot be corrected. Features.

  The invention according to claim 3 is the image forming apparatus according to claim 1 or 2, wherein when the detection unit determines that the image positional deviation cannot be corrected, the light amount of the image light is adjusted, and the pattern is again formed. It is characterized in that the image misregistration correction pattern is formed by the forming means and the image misregistration correction pattern is detected.

  According to a fourth aspect of the present invention, in the image forming apparatus according to the first or second aspect, the means for confirming the toner density and the means for confirming the toner density before forming the image misregistration correction pattern, A replenishing means for replenishing toner when the toner density becomes lower than a preset value is provided.

  According to a fifth aspect of the present invention, in the image forming apparatus according to the fourth aspect, the replenishing means replenishes the toner so as to have a value higher than a preset value.

  A sixth aspect of the present invention is the image forming apparatus according to the first or second aspect, wherein the notification means notifies the color that could not be detected by the detection means.

  The invention according to claim 7 is the image forming apparatus according to claim 1 or 2, wherein the detecting means counts the number of times that the image misregistration correction pattern cannot be detected and determines the number of times that the pattern cannot be detected. It has a number of times determination means, and notifies that the correction is impossible when the image misregistration correction pattern cannot be detected a certain number of times or more.

  According to an eighth aspect of the present invention, in the image forming apparatus according to the seventh aspect, when the number of times determination means cannot detect the image misregistration correction pattern continuously for a certain number of times or more, the correction is impossible. It is characterized by that.

  A ninth aspect of the present invention is the image forming apparatus according to the eighth aspect, wherein the number of times determined by the number-of-times determining means can be set in advance.

  11. The image forming apparatus control method according to claim 10, wherein at least two colors are provided for each color individually for forming a single color image, and an image color image is formed by superimposing at least two single color images. A method for controlling an apparatus, comprising: a pattern formation process for forming an image misregistration correction pattern; a detection process for detecting the position of an image misregistration correction pattern formed by the pattern forming means; and a detection by the detection means There is a correction process for each color for correcting the image position deviation based on the result, and a notification process for notifying the correction result, and if the image position deviation cannot be detected by the detection process, a single color printing is possible. This is characterized by notifying that correction is impossible.

  The image forming apparatus control method according to claim 11 forms a latent image by irradiating image light corresponding to image data onto a rotating or moving image carrier, and the latent image is developed by a developing unit. The image that has been imaged and visualized is transferred onto a recording medium conveyed by a transfer means that rotates or moves, or transferred to a transfer means that rotates or moves, and the image transferred to the transfer means is transferred. A plurality of image forming units that form a single color image on a recording medium by being transferred onto the recording medium, and a plurality of colors are formed on the recording medium by superimposing images formed by at least two image forming units on the recording medium. A method for controlling an image forming apparatus for forming an image, comprising: a pattern forming process for forming an image misregistration correction pattern; and an image formed by the pattern forming unit A detection process for detecting the position of the misalignment correction pattern, a correction process for each color for correcting the image position deviation based on the detection result by the detection means, and a notification process for notifying the correction result, When a color that cannot be detected in the misregistration detection process occurs, only the correctable color is corrected to enable single-color printing and multiple color combinations that do not use non-correctable colors, and are corrected by the notification process. It is characterized by notifying of impossibility.

  The invention described in claim 12 is the invention described in claim 10 or 11, wherein when it is determined that the image position deviation cannot be corrected by the detection process, the light amount of the image light is adjusted and the pattern formation process is performed again. The image misregistration correction pattern is formed by the method and the image misregistration correction pattern is detected.

  A thirteenth aspect of the invention is the invention of the tenth or eleventh aspect, in which the toner concentration is determined by a process for confirming the toner density and a process for confirming the toner density before forming the image misregistration correction pattern. And a replenishment stroke for replenishing the toner when the value becomes smaller than a preset value.

  According to a fourteenth aspect of the present invention, there is provided the image forming apparatus control method according to the tenth or eleventh aspect, wherein the toner is replenished so that the replenishment step has a value higher than a preset value. To do.

  A fifteenth aspect of the invention is the image forming apparatus control method according to the tenth or eleventh aspect of the invention, wherein the notification step notifies a color that could not be detected by the detection step.

  According to a sixteenth aspect of the present invention, there is provided the control method for the image forming apparatus according to the tenth or eleventh aspect, wherein the detection step counts the number of times that the image misregistration correction pattern cannot be detected, In this case, when the image misregistration correction pattern cannot be detected a predetermined number of times or more, a correction impossible notification is sent.

  According to a seventeenth aspect of the present invention, there is provided the image forming apparatus control method according to the tenth or eleventh aspect, wherein the number-of-times determination step is performed when the image misregistration correction pattern cannot be detected continuously for a certain number of times. The correction is impossible.

  According to an eighteenth aspect of the present invention, there is provided an image forming apparatus control method according to the tenth or eleventh aspect, wherein the number of times determined by the number of times determination step can be set in advance.

  20. The image forming apparatus control program according to claim 19, wherein the image forming apparatus includes at least two colors for each color, and forms a multicolor image by superimposing at least two monochrome images. An apparatus control program for causing an image forming apparatus to execute a process according to a process according to a control method according to any one of claims 10 to 19.

  A recording medium on which the control program for the image forming apparatus according to claim 20 is recorded, wherein the control program for the image forming apparatus according to claim 19 is recorded.

  The control program for an image forming apparatus according to claim 21 forms a latent image by irradiating image light corresponding to image data on a rotating or moving image carrier, and the latent image is developed by a developing means. The image that has been imaged and visualized is transferred onto a recording medium conveyed by a transfer means that rotates or moves, or transferred to a transfer means that rotates or moves, and the image transferred to the transfer means is transferred. A plurality of image forming units that form a single color image on a recording medium by being transferred onto the recording medium, and a plurality of colors are formed on the recording medium by superimposing images formed by at least two image forming units on the recording medium. A control program for an image forming apparatus for forming an image, the processing program according to the process according to any one of claims 10 to 19 being executed in the image forming apparatus. Characterized in that to.

  According to a twenty-second aspect of the present invention, there is provided a recording medium on which the control program for the image forming apparatus is recorded.

  The process cartridge according to claim 23, wherein each of the plurality of image carriers is combined with at least one of a charging unit, a developing unit, and a cleaning unit and is detachably installed in the image forming apparatus main body. The image forming apparatus includes a storage unit that stores a correction result of the image misregistration pattern, and the image forming apparatus determines a printable color and a combination of a plurality of printable colors from the correction result stored in the storage unit. And

  According to a twenty-fourth aspect of the present invention, in the process cartridge according to the twenty-third aspect, the storage unit updates the correction result every time the image displacement pattern is corrected.

  26. The process cartridge according to claim 25, wherein each of the plurality of image carriers includes a photosensitive unit combined with at least one of a charging unit and a cleaning unit, and a developing unit having a developing unit, both of which are image forming apparatuses. In the process cartridge that is detachably installed in the main body, at least one of the photosensitive unit and the developing unit has a storage unit that stores a correction result of the image displacement pattern, and the image forming apparatus includes the storage unit. A plurality of printable colors and a combination of printable multiple colors are determined from the correction results stored in the above.

  According to a twenty-sixth aspect of the present invention, in the process cartridge according to the twenty-fifth aspect, the storage means provided in at least one of the photosensitive unit and the developing unit is stored in the storage means every time the image positional deviation correction is performed. The correction result is updated.

  From the above description, when the image misregistration correction cannot be performed, the image forming apparatus according to the present invention performs a function for forming a single color image and a correction only for a correctable color, and does not use a single color or a color that cannot be corrected. By having a function of forming an image using colors, it is possible to form an image using a single color or two or more colors without downing the machine as much as possible.

Next, embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 illustrates the overall configuration of an electrophotographic apparatus to which an image forming apparatus of the present invention is applied.
The printer 100 of the electrophotographic apparatus has an intermediate transfer unit at the center, and the intermediate transfer unit includes an intermediate transfer belt 10 that is an endless belt. The intermediate transfer belt 10 is a multi-layer belt in which an elastic layer is provided on a base layer made of a material that hardly stretches, such as a fluorine resin with a small elongation, a rubber material with a large elongation, or a canvas. The elastic layer is formed, for example, by coating a fluorine-based resin or the like on the surface of fluorine-based rubber or acrylonitrile-butadiene copolymer rubber to form a coat layer with good smoothness.

  The intermediate transfer belt 10 is wound around three support rollers 14 to 16 and is driven to rotate clockwise. On the left of the second support roller 15 is an intermediate transfer member cleaning unit 17 that removes residual toner remaining on the intermediate transfer belt 10 after image transfer.

  The intermediate transfer belt 10 between the first support roller 14 and the second support roller 15 has black (K), yellow (Y), magenta (M), and cyan (C) along the moving direction. The image forming device 20 includes a photosensitive unit 40 for each color, a charger unit 18, a developing unit, and a cleaning unit. The image forming device 20 is detachably attached to the printer main body.

  Above the image forming apparatus 20, there is a writing unit 21 that irradiates each photosensitive drum of each color photosensitive unit with laser light for image formation.

  Below the intermediate transfer belt 10 is a secondary transfer unit 22. The secondary transfer unit 22 is arranged such that an endless secondary transfer belt 24 is stretched between two rollers 23 to push up the intermediate transfer belt 10 and press it against the third support roller 16. is there. The secondary transfer belt 24 transfers the image on the intermediate transfer belt 10 onto a sheet. Next to the secondary transfer device 22, there is a fixing unit 25 for fixing the transferred image on the paper, and the paper on which the toner image has been transferred is fed there. The fixing unit 25 is obtained by pressing a heating and pressure roller 27 against a fixing belt 26 that is an endless belt.

  Below the secondary transfer unit 22 and the fixing unit 25, there is a sheet reversing unit 28 that sends out the paper immediately after the image is formed on the front surface and reverses the front and back to record the image on the back surface.

  When the start switch of the operation unit 610 is pressed, if there is a document on the document feeding table 30 of the automatic document feeder (ADF) 120, the document is transported onto the contact glass 32. When there is no document in the ADF, the scanner of the image reading unit 110 is driven to read and scan the first carriage 33 and the second carriage 34 in order to read a manually placed document on the contact glass 32.

  Then, light is emitted from the light source on the first carriage 33 to the contact glass, and the reflected light from the document surface is reflected by the first mirror on the first carriage 33 toward the second carriage 34, and on the second carriage 34. The image is reflected on the mirror 36 and imaged on the CCD 36 as a reading sensor through the imaging lens 35. Based on the image signal obtained by the reading sensor 36, recording data of each color of K, Y, M, and C is generated.

  Further, when the start switch is pressed, when an image output instruction is issued from a personal computer or the like, or when a FAX output instruction is issued, the intermediate transfer belt 10 starts to be driven to rotate, and the image forming apparatus. Preparation of image formation of each unit 20 is started, and an image formation sequence of each color image is started, and an exposure laser modulated based on each color recording data is projected onto the photosensitive drum for each color. Each color toner image is transferred onto the intermediate transfer belt 10 as a single image by the process. When the leading edge of the toner image enters the secondary transfer unit 22, the sheet is sent to the secondary transfer unit 22 at a timing so that the leading edge enters the secondary transfer unit 22 at the same time. The upper toner image is transferred to the paper. The sheet on which the toner image has moved is sent to the fixing unit 25 where the toner image is fixed on the sheet.

  The above-described sheet is selectively rotated by driving one of the sheet feeding rollers 42 of the sheet feeding table 200, and the sheet is fed from one of the sheet feeding trays 44 provided in multiple stages in the sheet feeding unit 43. Only the sheet is separated, put in the transport roller unit 46, transported by the transport roller 47, guided to the transport roller unit 48 in the printer 100, and the transport roller unit 48 also abuts against the registration roller 49 and stops. Is sent to the secondary transfer unit 22.

  Paper can also be fed by inserting paper on the manual feed tray 51. When the user is inserting paper onto the manual feed tray 51, the printer 100 drives the paper feed roller 50 to separate one of the sheets on the manual feed tray 51 and pulls it into the manual paper feed path 53. Stop at 49.

The sheet discharged after receiving the fixing process in the fixing unit 25 is guided to the discharge roller 56 by the switching claw 55 and stacked on the discharge tray 57. Alternatively, the sheet is guided to the sheet reversing unit 28 by the switching claw 55, reversed there and led to the transfer position again, and after the image is recorded on the back surface, the sheet is discharged onto the paper discharge tray 57 by the discharge roller 56.
On the other hand, the residual toner remaining on the intermediate transfer belt 10 after image transfer is removed by the intermediate transfer body cleaning unit 17 to prepare for image formation again.

  In general, the registration roller 49 is often used while being grounded, but it is also possible to apply a bias voltage to remove paper dust from the paper. For example, a bias is applied using a conductive rubber roller. A conductive NBR rubber having a diameter of 18 mm and a thickness of 1 mm is used. The electrical resistance is about 109 Ωcm in volume resistance of the rubber material. The paper surface after passing through the registration roller 49 to which a bias is applied in this way is slightly charged on the negative side.

  Therefore, in the transfer from the intermediate transfer belt 10 to the sheet, there are cases where the transfer conditions are changed and the transfer conditions are changed as compared with the case where no voltage is applied to the registration roller 49. A voltage of about −800 V is applied to the intermediate transfer belt 10 on the toner transfer side (front side), and a voltage of about +200 V is applied to the back side of the paper by the transfer roller 62.

  FIG. 2 is a diagram showing a configuration of a four-drum type, so-called tandem type color image forming apparatus. The image forming apparatus 200 shown in FIG. 2 forms four sets of images to form a color image in which four color images of yellow (Y), magenta (M), cyan (C), and black (BK) are superimposed. (Photosensitive member 206, developing unit 207, charger 209, transfer unit 208) and four sets of light beam scanning devices 201 are provided.

  An image of the first color is formed on the recording paper 211 conveyed in the direction of the arrow by the transfer belt 210, and then the images of the four colors are superimposed by transferring the images in the order of the second, third, and fourth colors. A color image is formed on the recording paper 211, and the image on the recording paper 211 is fixed by a fixing device (not shown).

  Each color image forming unit is provided with a charger 209, a developing unit 207, a transfer unit 208, a cleaning unit (not shown), and a static eliminator (not shown) around the photosensitive member 206. An image is formed on the recording paper 211 by charging, exposure, development, and transfer, which are electrophotographic processes.

  The image forming apparatus of the present invention includes a sensor A and a sensor B for detecting an image misalignment correction pattern. Sensors A and B are reflection-type optical sensors that detect an image misalignment correction pattern (an oblique line pattern and a horizontal line pattern) formed on the transfer belt 210 shown in FIG. Based on this, the image position shift in the main scanning direction and the sub-scanning direction between the colors and the image magnification in the main scanning direction are corrected.

  The light beam scanning device 201 for each color is provided with an LD unit 202 that selectively emits a light beam by drive modulation in accordance with image data. The light beam emitted from the LD unit 202 is output by a polygon motor. The light is polarized by the rotating polygon mirror 203, passes through the fθ lens 204, passes through the BTL 205, is reflected by the mirror (not shown), and scans on the photoconductor 206. BTL is an abbreviation for Barrel Toroidal Lens, and performs focusing in the sub-scanning direction (condensing function and position correction in the sub-scanning direction (surface tilt, etc.)).

  Although not shown in the drawing, the synchronization for taking the write start timing in the main scanning direction by receiving the light beam polarized by the polygon mirror 203 ahead of the image writing position in the non-image writing area in the main scanning direction. A synchronization detection sensor that outputs a detection signal is provided.

Next, an image misregistration correction pattern formed on the transfer belt 210 shown in FIG. 3 will be described.
Diagonal line and horizontal line images are formed on the transfer belt 210 at preset timings for the respective colors. As the transfer belt 210 moves in the direction of the arrow, the diagonal lines and horizontal lines of the respective colors are detected by the sensors A and B and sent to the printer control unit 230 (shown in FIG. 4). ) Is calculated. The detection timing of the oblique line is changed by shifting the image position in the main scanning direction, and the image magnification fluctuation in the main scanning direction can also be detected by detecting the oblique lines at both ends. The detection timing of the horizontal line changes as the image position in the sub-scanning direction shifts.

  The calculated time is compared with a preset time, and the amount of deviation in the main scanning direction, the magnification error in the main scanning direction, and the amount of deviation in the sub scanning direction with respect to the reference BK are calculated. The image writing position is corrected by changing it in units of one cycle of the clock VCLK, and the image magnification in the main scanning direction is corrected by changing the frequency of the clock WCLK from the writing clock generator 224 (shown in FIG. 4). Then, the image writing position in the sub-scanning direction is corrected by changing it in units of one cycle (one line unit) of the synchronization detection signal / DETP.

Next, the image formation control unit shown in FIG. 4 will be described.
A synchronization detection sensor 215 for detecting a light beam is provided on the image writing side at the end in the main scanning direction of the light beam scanning device 201, and the light beam transmitted through the fθ lens 204 is reflected by the mirror 213 and condensed by the lens 214. Thus, it is configured to enter the synchronization detection sensor 215.

  As the light beam passes over the sensor, a synchronization detection signal / DETP is output from the sensor and sent to the phase synchronization clock generation unit 225, the synchronization detection lighting control unit 223, and the writing start position control unit 221. The phase synchronization clock generation unit 225 generates a clock VCLK synchronized with / DETP from the clock WCLK generated by the write clock generation unit 224 and the synchronization detection signal / DETP, and outputs an LD control unit 222, a synchronization detection lighting control unit 223, and The data is sent to the writing start position control unit 221.

  The synchronization detection lighting control unit 223 first turns on the LD forced lighting signal BD to forcibly light the LD in order to detect the synchronization detection signal / DETP. However, after detecting the synchronization detection signal / DETP, Based on the signal / DETP and the clock VCLK, an LD forcible lighting signal BD for lighting the LD is generated at a timing at which the synchronization detection signal / DETP can be reliably detected without causing flare light, and is sent to the LD controller 222.

The LD controller 222 controls the lighting of the LD according to the pulse signal width generated from the synchronous detection forced lighting signal and the image signal synchronized with the clock VCLK. Then, a laser beam is emitted from the LD unit 202, is polarized by the polygon mirror 203, passes through the fθ lens 204, and scans on the photosensitive member.
The polygon motor drive control unit 220 controls the rotation of the polygon motor at a specified number of rotations based on a control signal from the printer control unit 230.

  The image misregistration correction pattern signal read by the sensors A and B is sent to the printer control unit 230, and the misregistration amount (time) of each color with respect to BK is calculated. Then, in order to correct the writing start position in the main scanning direction and the sub-scanning direction, the correction data is sent to the writing start position control unit 221 so that the timings of the main scanning gate signal / LGATE and the sub-scanning gate signal / FGATE are set. It is variable. Further, in order to correct the image magnification, the frequency of the clock WCLK is varied by sending frequency setting data to the write clock generator 224.

  The printer control unit 230 is connected to a charging potential control unit 226, a development bias control unit 227, a transfer bias control unit 228, and a toner density control unit 229, and performs control according to an instruction from the printer control unit 230. An operation panel 231 is connected to the printer control unit 230 so that display and data input can be performed.

Next, the configuration of the LD shown in FIG. 5 will be described.
The LD is composed of an LD (laser diode) and a PD (photodiode). The LD drive unit 240 controls the LD current Id so as to keep the PD monitor voltage Vm constant in order to light the LD with the amount of light instructed by the printer control unit 230 (APC operation: auto power control). When changing the amount of light, Vm is changed according to an instruction from the printer control unit 230, and the LD current Id is controlled so as to keep the set Vm constant.

Next, the configuration of the LD control unit 222 shown in FIG. 6 will be described.
The LD control unit 222 is divided into a PWM signal generation unit 241 that controls the lighting time of the LD and an LD driving unit 240 that controls the lighting of the LD. The PWM signal generation unit 241 outputs a PWM signal to the LD driving unit 240 based on the image data and the control signal 1 from the printer control unit 230, and the LD driving unit 240 lights the LD for that time.

  Further, by sending the LD forced lighting signal BD from the synchronization detection lighting control unit 223 to the LD driving unit 240, the LD is lit for that time. The amount of light when turning on the LD is set by a control signal 2 from the printer control unit 230.

  The image data may be 1 bit width or plural bits (2 bit width or more). For example, in the case of 1 bit width, it may be configured to generate a predetermined pulse width, or a control signal 1 from the printer control unit 230. The pulse width may be selected by (selection signal) and output. In the case of a plurality of bits (2 bit width or more), it may be configured to generate a pulse width corresponding to each image data. Alternatively, the pulse width corresponding to the image data may be variable by a control signal (selection signal) from the printer control unit 230.

Next, the configuration of the writing start position control unit 221 shown in FIG. 7 will be described.
The writing start position control unit 221 is divided into a main scanning line synchronization signal generation unit 254, a main scanning gate signal generation unit 260, and a sub scanning gate signal generation unit 250. The main scanning line synchronization signal generation unit 254 generates a signal / LSYNC for operating the main scanning counter 263 in the main scanning gate signal generation unit and the sub scanning counter 253 in the sub scanning gate signal generation unit, and the main scanning gate signal generation unit 260 generates a signal / LGATE that determines the capture timing of the image signal (image writing timing in the main scanning direction), and the sub-scan gate signal generator 250 determines the capture timing of the image signal (image writing timing in the sub-scanning direction). The signal / FGATE to be generated is generated.

  The main scanning gate signal generation unit 260 compares the main scanning counter 263 operating at / LSYNC and VCLK, the counter value with the correction data 1 from the printer control unit 230, and outputs the result from the comparator 262 and the comparator 262. The gate signal generation unit 261 generates / LGATE from the comparison result.

  The sub-scanning gate signal generation unit 250 compares the control signal from the printer control unit 230 with the sub-scanning counter 253 operating at / LSYNC and VCLK, the counter value and the correction data 2 from the printer control unit 230, and the result is obtained. It comprises a comparator 252 that outputs and a gate signal generator 251 that generates / FGATE from the comparison result from the comparator 252.

  The writing start position control unit 221 can correct the writing position in units of one cycle of the clock VCLK for main scanning, that is, in units of one dot, and for sub-scanning in units of one cycle of / LSYNC, that is, in units of one line.

Next, a preceding example of the image formation control unit shown in FIG. 8 will be described.
The line memory 270 is provided in the preceding stage, and image data captured from an external device such as a frame memory or a scanner at the timing of / FGATE is output in synchronization with VCLK only during a period where / LGATE is 'L'. The output image signal is sent to the LD control unit 222, and the LD is turned on at that timing.

  Therefore, by changing the correction data set in the comparator by the printer control unit 230, the timing of / LGATE and / FGATE is changed, the timing of the image signal is also changed, and the image writing start position in the main scanning direction and the sub-scanning direction is changed. Will change.

Next, a timing chart of the writing start position control unit 221 shown in FIG. 9 will be described.
/ LSYNC resets the counter, counts up with VCLK, and when the counter value reaches the correction data (in this case, 'X') set by the printer control unit 230, the comparison result is output from the comparator. / LGATE becomes 'L' (valid) by the signal generator. / LGATE is a signal that becomes 'L' by the image width in the main scanning direction. The sub-scan is different in that it counts up with / LSYNC.

  Next, the configurations and processing operations of the image forming apparatus and the process cartridge of the present invention will be described with reference to the first to twelfth embodiments.

(First embodiment)
FIG. 10 is a flowchart showing the processing operation of image misregistration correction in the first embodiment.
In the first embodiment, the main scanning image position, sub-scanning image position, and main scanning image magnification of other colors are corrected using BK (black) as a reference, so that detection is performed for all colors, but correction is performed. Is a color other than BK.

  First, a pattern is formed (step S10). Here, an image misregistration correction pattern is formed on the transfer belt 210. Next, it detects with a sensor (step S11). Here, the image misregistration correction pattern formed on the transfer belt 210 is detected by a sensor. Next, when detecting by the sensor, it is determined whether the detection level of the image misregistration correction pattern is a level at which image misregistration can be detected (step S12).

  If it is detectable (step S12 / YES), the amount of deviation is calculated (step S13). Here, the printer controller 230 detects the main scanning deviation amount, sub-scanning deviation amount, and main scanning magnification error amount with respect to BK. Next, it is determined whether to correct (step S14). Here, since the correction accuracy is in units of one dot and one line, correction is performed if the shift amount is 1/2 dot or more and 1/2 line or more.

  When correction is not performed (step S14 / NO), the process is terminated as it is. When correction is performed (step S14 / YES), correction data is calculated (step S15), and correction data is set (step S16).

Here, first, correction data 1 is set in the main scanning gate signal generation unit 260 and correction data 2 is set in the sub-scanning gate signal generation unit 250 to generate / LGATE and / FGATE.
Also for main scanning magnification error correction, it is determined whether the detected magnification error has a level to be corrected, and this determination is also determined by the magnification correction accuracy.
When correcting the image magnification, a set value of a frequency necessary for correcting the image magnification is calculated, set to the write clock generation unit 224, and a clock WCLK is generated.

  If the image cannot be detected (NO in step S12), the image misregistration correction cannot be executed, so an error (cannot be corrected) is displayed on the operation panel 231 and the output of the full color image is stopped. However, monochrome and mono color output is possible because there is no problem even if the image position is shifted. For a color that could not be detected, a flag that does not perform image formation is set, and when a normal image is formed, naturally a full color image cannot be formed, but a color other than the color that could not be detected is used, and a single color is used. By enabling the image forming operation, it is not necessary to bring down the machine completely until the serviceman repairs.

Further, by displaying the color that could not be detected on the operation panel 231 and allowing the user to select which color is to be printed in a single color, the user can easily and arbitrarily determine the color to be output.
Further, in the case of a FAX image, image output may be performed based on the priority order using the color detected by the user setting the priority order.

(Second Embodiment)
FIG. 11 is a flowchart showing a processing operation for image misregistration correction in the second embodiment.
In the second embodiment, when the image misalignment correction pattern cannot be detected, the image forming condition is changed and the image misalignment correction pattern is detected again.
First, a pattern is formed (step S20). Here, an image misregistration correction pattern is formed on the transfer belt 210. Next, it detects with a sensor (step S21). Here, the image misregistration correction pattern formed on the transfer belt 210 is detected by a sensor. Next, when detecting by the sensor, it is determined whether the detection level of the image misregistration correction pattern is a level at which image misregistration can be detected (step S22).

If the detection level of the image misalignment correction pattern cannot detect the image misalignment (step S22 / NO), the light amount setting value is changed (step S23). The change in the light amount setting value is, for example, a change in the light amount of the LD. Then, an image misregistration correction pattern of the transfer belt 210 is formed again (step S24), and the image misregistration correction pattern is detected by a sensor (step S25). If the image misalignment correction pattern cannot be detected by the sensor even if the light amount setting value is changed (step S26 / NO), an error (cannot be corrected) is displayed on the operation panel 231 and the output of the full color image is stopped.
Note that the processing operations in steps S27 to S30 are the same as those in steps S13 to S16 described in the first embodiment, and thus description thereof is omitted.

  In the second embodiment, the setting value of the light amount of the LD is changed. However, the present invention is not limited to this, and the light emission time (PWM) of the LD may be used, and the development bias voltage, the transfer current, and the like may be used.

(Third embodiment)
In the third embodiment, the current toner density is checked before the image misalignment correction pattern forming operation, and if it is smaller than a preset value, the toner replenishing operation is performed, and then the pattern forming operation is performed. .

First, FIG. 12 shows the relationship between the toner concentration and the toner adhesion amount.
In the graph shown in FIG. 12, the horizontal axis represents the toner density (TC), and the vertical axis represents the toner adhesion amount. If the toner concentration is too low, image fading will occur, and if the toner concentration is too high, background smear will occur. Therefore, the toner concentration is usually controlled to be between C and D.

  The case where the density of the image misregistration correction pattern decreases and detection becomes impossible is when the toner density is near C or below C. Therefore, when forming the image misregistration correction pattern, the toner is replenished. Thus, by temporarily increasing the toner density, the density of the image misregistration correction pattern can be increased.

Next, the image misalignment correction processing operation in the third embodiment will be described with reference to FIG.
First, as shown in the graph of FIG. 12, the toner density (TC) is controlled between C and D. Therefore, an intermediate value between C and D is set as a determination value E, and it is determined whether the toner density (TC) is lower than the determination value E (step S40). When the toner density (TC) is lower than the determination value E (step S40 / YES), a toner supply operation is performed (step S41).
Note that steps S42 to S49 are the same as the processing operations of steps S10 to S17 described in the first embodiment, and thus description thereof is omitted.

(Fourth embodiment)
Next, the image misalignment correction processing operation in the fourth embodiment will be described with reference to FIG.
In the fourth embodiment, correction is executed for the detected color, so that an error is displayed for the color that could not be detected (corrected).
In step S52, when it is determined whether the detection level of the image misregistration correction pattern is a level at which image misregistration can be detected (step S52 / NO), an uncorrectable color is notified (step S57). ). Here, the color that could not be detected is displayed on the operation panel 231. Therefore, the output of the full color image is stopped, but the corrected color can be output as a single color or a combination of a plurality of colors. In addition, the detected color is displayed on the operation panel 231 so that the user can select which color is to be printed in a single color or which color is to be combined, so that the user can easily and arbitrarily output the color. Can be determined.
Note that the processing operations in step S50 to step S56 are the same as those in step S10 to step S16 described in the first embodiment, and thus description thereof is omitted.

(Fifth embodiment)
Next, the image misalignment correction processing operation in the fifth embodiment will be described with reference to FIG.
In the fifth embodiment, the number of times that the image misregistration correction pattern cannot be detected is counted, and when the number exceeds the preset number, an error (cannot be corrected) is displayed on the operation panel 231 and a full color image is output. Stop.
In step S62, when it is determined whether the detection level of the image misalignment correction pattern is a level at which image misalignment can be detected (step S62 / NO), n = 0 (the number of detected NG times) when the power is turned on. = 0), the number of detected NGs is counted (step S66), and it is determined whether the number of detected NGs is 5 or more (step S67). If the number of detected NGs is 5 or more (step S67 / YES), the correction is notified (step S68), and the process ends. If the number of detected NGs is not 5 times or more (step S67 / NO), the process ends as it is.

In the fifth embodiment, an error is detected when n = 5. However, the present invention is not limited to this, and the number of errors may be determined from the number of times that correction was not possible and the actual image position shift state. Even if the number of times of detection could not be the same, comparing the case where it was NG five times in succession with the case where it was not so, naturally the case where it became NG continuously has a greater effect on the image, The possibility that the machine is out of order is also high. If it is sometimes NG, there may be a sudden detection error. Therefore, the machine failure can be detected more reliably and the influence on the image can be surely determined by determining the number of consecutive NG times.
In addition, since the processing operation in step S60-step S66 is the same as that of step S10-step S16 shown in 1st Embodiment, description is abbreviate | omitted.

(Sixth embodiment)
In the sixth embodiment, similarly to the above-described example, an error is displayed in the same manner, but it is also possible to print colors that could not be detected (including full-color printing) by user selection. Depending on the user, even if an image position shift occurs, it may be acceptable depending on the level. In that case, by making it possible to select printing, it is possible to cope with any user.

(Seventh embodiment)
Next, with reference to FIG. 16, the structure of the process cartridge in 7th Embodiment is demonstrated.
In the process cartridge, a photosensitive member, a charging unit, a developing unit, and a cleaning unit are integrally coupled. Each process cartridge is an independent unit for each color, and the process cartridge is detachable from the image forming apparatus shown in FIG.

  The process cartridge shown in FIG. 16 includes a developing unit 284, a charging unit 287, a cleaning unit 291 and a photoreceptor 292. More specifically, the developing unit 284 includes a developing roller 280, a toner density sensor 281, a conveying screw 282, and a developing doctor blade 283.

  The charging unit 287 includes a charging roller 285 and a charging cleaning roller 286, and the cleaning unit 291 includes a cleaning blade 288, a cleaning brush 289, and a waste toner transport coil 290.

Next, the operation of the process cartridge will be described.
The toner conveyed from the toner cartridge (not shown) to the developing unit is agitated with the developer by the conveying screw 282 and conveyed to the developing roller 280. The amount of the agent on the developing roller 280 is regulated by the developing doctor blade 283 and supplied onto the photoreceptor 292. The developing unit 284 includes a toner concentration sensor 281 that detects the toner concentration in the agent and controls the toner concentration.

  Charging of the photosensitive drum 292 is performed by a charging roller 285. The charging roller 285 rotates in the opposite direction to the photosensitive drum 292, and uniformly charges the surface of the photosensitive drum 292. Further, on the upper side of the charging roller 285, a charging cleaning roller 286 is attached in a state of being permanently installed with the charging roller 285, and the charging roller 285 is cleaned.

  Untransferred toner on the photosensitive drum 292 is collected by the cleaning blade 288 and the cleaning brush 289 of the cleaning unit. The cleaning blade 288 is attached to the photosensitive drum 292 in the counter direction, and is permanently provided with the photosensitive drum 292. The cleaning brush 289 rotates in the opposite direction to the photosensitive drum 292, collects untransferred toner together with the cleaning blade 288, and sends it to the waste toner transport coil 290 side. The waste toner is transported from the waste toner transport coil 290 to a waste toner discharge port and collected by a waste toner bottle (not shown).

(Eighth embodiment)
Next, a process cartridge according to the eighth embodiment will be described with reference to FIG.
In the eighth embodiment, the process cartridge is provided with a memory for storing the result of the image misregistration correction.
The memory 300 stores the result of the color for which the image misregistration pattern could not be detected in the corresponding process cartridge, so that the process cartridge has a cause and is mounted on another machine. The error recording becomes valid.
When the image cartridge is corrected again when the process cartridge is replaced, if it can be detected at that time, a printable record is stored, and the machine returns.
Further, by storing the correction result history, for example, by storing the number of NG times, it is possible to determine that correction is impossible using the number of times.

(Ninth embodiment)
Next, a process cartridge according to the ninth embodiment will be described with reference to FIG.
In the process cartridge according to the ninth embodiment, the photosensitive unit and the developing unit 284 are independent units for each color. The photosensitive unit and the developing unit 284 are configured to be detachable from the image forming apparatus 200 shown in FIG.

  With respect to the developing unit 284, the toner conveyed from the toner cartridge (not shown) to the developing unit 284 is stirred with the developer by the conveying screw 282 and conveyed to the developing roller 280. The amount of the agent on the developing roller 280 is regulated by the developing doctor blade 283 and supplied onto the photoreceptor 292. The developing unit 284 includes a toner concentration sensor 281 that detects the toner concentration in the agent and controls the toner concentration.

  Regarding the photosensitive unit, charging to the photosensitive drum 292 is performed by the charging roller 285. The charging roller 285 rotates in the opposite direction to the photosensitive drum 292, and uniformly charges the surface of the photosensitive drum 292. Further, on the upper side of the charging roller 285, a charging cleaning roller 286 is attached in a state of being permanently installed with the charging roller 285, and the charging roller 285 is cleaned.

  Untransferred toner on the photosensitive drum 292 is collected by a cleaning blade 288 and a cleaning brush 289. The cleaning blade 288 is attached to the photosensitive drum 292 in the counter direction, and is permanently provided with the photosensitive drum 292. The cleaning brush 288 rotates in the opposite direction to the photosensitive drum 292, collects untransferred toner together with the blade, and sends it to the waste toner conveying coil 290 side. The waste toner is transported from the waste toner transport coil 290 to a waste toner discharge port and collected by a waste toner bottle (not shown).

(Tenth embodiment)
With reference to FIG. 19, the structure of the process cartridge in the tenth embodiment will be described.
In the tenth embodiment, the photoconductor unit is provided with a memory 400 for storing the result of image positional deviation correction. The memory 400 stores the result of the color for which the image misregistration pattern could not be detected in the corresponding photoconductor unit. If there is a cause in the photoconductor unit, it is mounted on another machine. Even in that case, the error recording becomes effective. If the image position deviation correction is executed again when the photoconductor unit is replaced, if it can be detected at that time, a printable record is stored, and the machine returns.
Further, by storing the correction result history, for example, by storing the number of NG times, it is possible to determine that correction is impossible using the number of times.

(Eleventh embodiment)
The configuration of the process cartridge shown in the eleventh embodiment will be described with reference to FIG.
The process cartridge shown in the eleventh embodiment includes a memory 300 that stores a result of image positional deviation correction in the developing unit 284.
By storing the results of the colors for which the image misregistration pattern could not be detected in the corresponding developing unit 284, if the developing unit 284 has a cause, the error may occur even if it is mounted on another machine. Recording is enabled.
When the developing unit 284 is replaced, if the image misregistration correction is executed again, if it can be detected at that time, a printable record is stored, and the machine returns.
Further, by storing the correction result history, for example, by storing the number of NG times, it is possible to determine that correction is impossible using the number of times.

(Twelfth embodiment)
With reference to FIG. 21, the structure of the process cartridge in the twelfth embodiment will be described.
In the twelfth embodiment, the photoconductor unit and the developing unit 284 are provided with a memory 300 and a memory 400 for storing the result of image positional deviation correction.
By storing the results of the color whose image position misregistration pattern could not be detected in the corresponding photosensitive unit and developing unit 284, if there is a cause in both the photosensitive unit and developing unit 284, other The error record is also effective when installed in other machines.

Even if one of the causes is present, if the image position deviation correction is performed again when the photosensitive unit or the developing unit 284 is replaced, if the detected unit can be detected at that time, the replaced unit is called NG. The possibility is high, and if it cannot be detected again, the unit that has not been replaced is likely to be NG. If detection is possible by exchanging one or both, printable records are stored in each unit, and the machine is restored.
Further, by storing the correction result history, for example, by storing the number of NG times, it is possible to determine that correction is impossible using the number of times.

1 is a diagram illustrating a configuration of an electrophotographic apparatus to which an image forming apparatus of the present invention is applied. 1 is a diagram illustrating a configuration of an image forming apparatus according to an embodiment of the present invention. It is a figure showing a pattern for image position shift amendment in an embodiment of the present invention. FIG. 3 is a diagram illustrating a configuration of an image formation control unit in the embodiment of the present invention. It is the figure which showed the structure of LD in embodiment of this invention. It is the figure which showed the structure of the LD control part in embodiment of this invention. It is the figure which showed the structure of the writing start position control part in embodiment of this invention. FIG. 4 is a diagram illustrating an example of a front stage of an image formation control unit in the embodiment of the present invention. It is the figure which showed the timing chart of the writing start position control part in embodiment of this invention. 5 is a flowchart showing a processing operation for image misregistration correction in the first embodiment of the present invention. 12 is a flowchart illustrating a processing operation for image misregistration correction according to the second embodiment of the present invention. 10 is a graph showing the relationship between toner density and toner adhesion amount in the third embodiment of the present invention. 10 is a flowchart illustrating an image misregistration correction processing operation according to a third embodiment of the present invention. It is the flowchart which showed the processing operation of the image displacement correction | amendment in the 4th Embodiment of this invention. It is the flowchart which showed the processing operation of the image displacement correction in the 5th execution form of this invention. It is the figure which showed the structure of the process cartridge in the 7th Embodiment of this invention. It is the figure which showed the structure of the process cartridge in the 8th Embodiment of this invention. It is the figure which showed the structure of the process cartridge in the 9th Embodiment of this invention. It is the figure which showed the structure of the process cartridge in the 10th Embodiment of this invention. It is the figure which showed the structure of the process cartridge in the 11th Embodiment of this invention. It is the figure which showed the structure of the process cartridge in the 12th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 200 Image forming apparatus 201 Light beam scanning apparatus 202 LD unit 203 Polygon mirror 204 f (theta) lens 205 BLT
206 Photoconductor 207 Development unit 208 Transfer device 209 Charger 210 Transfer belt 211 Recording paper 212 Conveyance motor

Claims (26)

An image forming apparatus for forming a multicolor image by providing a unit for forming a single color image for at least two colors for each color, and superposing at least two single color images.
Pattern forming means for forming an image misregistration correction pattern;
Detecting means for detecting a position of the image misregistration correction pattern formed by the pattern forming means;
Correction means provided for each color for correcting image positional deviation based on the detection result by the detection means;
Notification means for notifying the correction result,
An image forming apparatus characterized in that, when an image position shift cannot be detected by the detecting means, monochrome printing is possible, and a notification means notifies that correction is impossible. A latent image is formed by irradiating image light corresponding to image data on a rotating or moving image carrier, the latent image is visualized by a developing unit, and the visualized image is rotated or rotated. The image is transferred onto the recording medium conveyed by the moving transfer means, or transferred to the rotating or moving transfer means, and the image transferred to the transfer means is transferred onto the recording medium, thereby being monochromatic on the recording medium. An image forming apparatus comprising a plurality of image forming units for forming an image, and forming a multicolor image on the recording medium by superimposing images formed by at least two image forming units on the recording medium,
Pattern forming means for forming an image misregistration correction pattern;
Detecting means for detecting a position of the image misregistration correction pattern formed by the pattern forming means;
Correction means provided for each color for correcting image positional deviation based on the detection result by the detection means;
A notification means for notifying the correction result;
Image misregistration When a color that cannot be detected by the detection means is generated, only the correctable color is corrected to enable single color printing and a combination of a plurality of colors that do not use a color that cannot be corrected. An image forming apparatus characterized by notifying that correction is impossible by means.   When the detection unit determines that the image misregistration cannot be corrected, the light amount of the image light is adjusted, and the pattern forming unit again forms the image misregistration correction pattern and the image misregistration correction. The image forming apparatus according to claim 1, wherein a pattern is detected. Means for confirming toner density before forming the image misregistration correction pattern;
3. The image forming apparatus according to claim 1, further comprising a replenishing unit configured to replenish toner when the toner concentration is less than a preset value by the means for confirming the toner concentration.   The image forming apparatus according to claim 4, wherein the replenishing unit replenishes toner so as to have a value higher than a preset value.   The image forming apparatus according to claim 1, wherein the notification unit notifies a color that could not be detected by the detection unit. The detection means includes a number of times determination means for counting the number of times that the image misregistration correction pattern could not be detected and determining the number of times that the pattern could not be detected.
3. The image forming apparatus according to claim 1, wherein when the image misregistration correction pattern cannot be detected a predetermined number of times or more, the correction impossible is notified.   8. The image forming apparatus according to claim 7, wherein the number of times determination means makes correction impossible when the image misregistration correction pattern cannot be detected continuously for a certain number of times or more.   The image forming apparatus according to claim 8, wherein the number of times determined by the number determination unit can be set in advance. A method for controlling an image forming apparatus that includes at least two colors for forming a single-color image for each color, and superimposes at least two single-color images to form a color image.
A pattern forming process for forming an image misalignment correction pattern;
A detection step of detecting a position of the image misregistration correction pattern formed by the pattern forming unit;
A correction step provided for each color for correcting the image position deviation based on the detection result by the detection means;
A notification process for notifying the correction result,
A method for controlling an image forming apparatus, wherein when an image misregistration cannot be detected by the detection process, monochrome printing is possible, and correction is not notified by a notification process. A latent image is formed by irradiating image light corresponding to image data on a rotating or moving image carrier, the latent image is visualized by a developing unit, and the visualized image is rotated or rotated. The image is transferred onto the recording medium conveyed by the moving transfer means, or transferred to the rotating or moving transfer means, and the image transferred to the transfer means is transferred onto the recording medium, thereby being monochromatic on the recording medium. A method of controlling an image forming apparatus that includes a plurality of image forming units that form images and superimposes images formed by at least two image forming units on the recording medium to form a multicolor image on the recording medium. And
A pattern forming process for forming an image misalignment correction pattern;
A detection step of detecting a position of the image misregistration correction pattern formed by the pattern forming unit;
A correction step provided for each color for correcting the image position deviation based on the detection result by the detection means;
It has a notification process to notify the correction result,
Image misregistration When a color that cannot be detected in the detection process occurs, only a correctable color is corrected, and single color printing and a combination of a plurality of colors that do not use a color that cannot be corrected are enabled. A control method for an image forming apparatus, wherein a notification that correction is impossible is made according to a process.   When it is determined that the image displacement cannot be corrected by the detection process, the light amount of the image light is adjusted, and the formation of the image displacement correction pattern by the pattern formation process and the image displacement correction are performed again. 12. The method of controlling an image forming apparatus according to claim 10, wherein pattern detection is performed. Before forming the image misregistration correction pattern, a step of checking the toner density;
12. The method of controlling an image forming apparatus according to claim 10, further comprising a replenishment step of replenishing toner when the toner concentration becomes lower than a preset value by the step of checking the toner concentration. .   12. The method of controlling an image forming apparatus according to claim 10, wherein the toner is replenished so that the replenishment step has a value higher than a preset value.   12. The method of controlling an image forming apparatus according to claim 10, wherein the notification step notifies a color that could not be detected by the detection step. The detection step includes a number determination step of counting the number of times the image misregistration correction pattern could not be detected and determining the number of times the detection was not possible,
12. The method of controlling an image forming apparatus according to claim 10 or 11, wherein when the image misregistration correction pattern cannot be detected a predetermined number of times or more, a correction impossibility is notified.   12. The method of controlling an image forming apparatus according to claim 10 or 11, wherein the number determination step is disabled when the image misregistration correction pattern cannot be detected continuously for a certain number of times or more. .   12. The method of controlling an image forming apparatus according to claim 10, wherein the number of times determined by the number determination step can be set in advance. A control program for an image forming apparatus for forming a multicolor image by providing at least two colors for each color individually and forming a multicolor image by superimposing at least two monochrome images.
20. A control program for an image forming apparatus, which causes the image forming apparatus to execute a process according to a process according to any one of claims 10 to 19.   20. A recording medium recording an image forming apparatus control program according to claim 19, wherein the image forming apparatus control program is recorded. A latent image is formed by irradiating image light corresponding to image data on a rotating or moving image carrier, the latent image is visualized by a developing unit, and the visualized image is rotated or rotated. Transfer onto a recording medium conveyed by a moving transfer means, or transfer onto a recording medium conveyed by a rotating or moving transfer means, or transfer to a rotating or moving transfer means, and the transfer A plurality of image forming units that form a single color image on the recording medium by transferring the image transferred to the recording medium onto the recording medium, and superimposing images formed by at least two image forming units on the recording medium; A control program for an image forming apparatus for forming a multicolor image on the recording medium,
20. A control program for an image forming apparatus, which causes the image forming apparatus to execute a process according to a process according to any one of claims 10 to 19.   23. A recording medium on which the control program for an image forming apparatus according to claim 21 is recorded. Each of the plurality of image carriers is combined with at least one of a charging unit, a developing unit, and a cleaning unit, and is detachably installed in the image forming apparatus main body.
Storage means for storing the result of correcting the image displacement pattern;
The image forming apparatus determines a printable color and a combination of a plurality of printable colors from a correction result stored in the storage unit.   24. The process cartridge according to claim 23, wherein the storage unit updates the correction result every time the image positional deviation pattern is corrected. Each of the plurality of image carriers is a photosensitive unit combined with at least one of charging means and cleaning means,
In a process cartridge that includes a developing unit having a developing means and is detachably installed in the image forming apparatus main body,
At least one of the photosensitive unit and the developing unit has a storage unit that stores a result of correcting the image misregistration pattern,
The process cartridge according to claim 1, wherein the image forming apparatus determines a printable color and a combination of a plurality of colors that can be printed from a correction result stored in the storage unit.   26. The storage means provided in at least one of the photosensitive unit and the developing unit updates a correction result stored in the storage means every time image position deviation correction is performed. Process cartridge.

Images