JP2011064830A - Light scanning device, image forming apparatus, method for controlling image forming apparatus, and program for controlling image forming apparatus - Google Patents

Abstract

It is possible to suppress deterioration of image quality.
A CPU 27 determines, for each image carrier 2a, 2b, 2c, 2d, whether the light beam detected by a synchronous sensor 21, 22 is based on forward scanning or backward scanning. Based on this, by controlling the writing control unit 26 of each image carrier, the scanning start direction of the light beam is controlled in the same direction among the image carriers 2a, 2b, 2c and 2d. As a result, it is possible to suppress the occurrence of color misregistration, color unevenness, or the like at the edge of the color image due to the skew angle of the light beam being different between the image carriers 2a, 2b, 2c, 2d, thereby deteriorating the image quality.
[Selection] Figure 2

Description

  The present invention relates to an optical scanning device, an image forming apparatus, an image forming apparatus control method, and an image forming apparatus control program.

  The tandem color image forming apparatus reciprocates laser beams (scanning lines) on the surfaces of a plurality of image carriers rotating in the sub-scanning direction, whereby yellow (Y) and magenta ( M), an electrostatic latent image corresponding to each color such as cyan (C) and black (K) is formed. Then, the color image forming apparatus executes an electrophotographic process such as development on the electrostatic latent image, and transfers toner images of different colors on the surface of each image carrier to a transfer medium. A color image is formed on top.

  In this type of color image forming apparatus, if there is a positional shift between the toner images of the respective colors, a positional shift (color shift) occurs in the color image formed on the paper, so that a high-quality color image can be obtained. Can not. Therefore, in this type of color image forming apparatus, it is necessary to perform color misregistration correction in order to accurately align the formation positions of the toner images of the respective colors. From such a background, in recent years, based on the amount of deviation of the scanning line when forming the electrostatic latent image of the other color with respect to the scanning line when forming the electrostatic latent image of the reference color, the electrostatic latent image of each color There has been proposed a technique for correcting the relative positional deviation of the scanning lines when forming the pattern (see Patent Document 1).

  In general, when a laser beam is reciprocated in the main scanning direction with respect to an image carrier that rotates in the sub-scanning direction, the writing angle (skew angle) of the scanning line with respect to the image carrier is determined by the forward scanning line and the backward scanning line. Different. However, the above conventional technique selects, for each image carrier, a scan line with a small amount of deviation from the scan line when forming the electrostatic latent image of the reference color, among the forward scan line and the return scan line. Correct color misregistration. That is, the above-described conventional technique performs color misregistration correction for each image carrier without considering the difference in skew angle between the forward scanning line and the backward scanning line. For this reason, according to the above-described prior art, when the skew angle of the scanning line is different between the image carriers, color misregistration or color unevenness may occur at the end of the color image, and the image quality may deteriorate.

  SUMMARY An advantage of some aspects of the invention is that it provides an optical scanning device, an image forming apparatus, an image forming apparatus control method, and an image forming apparatus capable of suppressing deterioration in image quality. It is to provide a control program.

  In order to solve the above-described problems and achieve the object, the present invention provides a plurality of polarizing means for reciprocating a light beam and light that is provided at both ends in the reciprocating scanning direction of the light beam and reciprocally scanned by the polarizing means. A plurality of detection means for detecting the beam, a synchronization determination means for determining whether the light beam detected by the detection means is forward scanning or backward scanning for each of the plurality of polarization means, and determination by the synchronization determination means There is provided an optical scanning device including a control unit that controls a scanning start direction of a light beam in the same direction among a plurality of polarization units based on the result.

  In order to solve the above-described problems and achieve the object, the present invention provides a swingable reflection mirror that reflects a light beam emitted from a light source, and light reflected by the reflection mirror by swinging the reflection mirror. A mirror control unit that reciprocates the beam on the image carrier that rotates in the sub-scanning direction, a light sensor that detects the light beam provided at both ends of the reciprocating scanning direction of the light beam, and a light sensor that detects the light beam A synchronization determination unit that determines whether the light beam is due to forward scanning or backward scanning, and write control that controls the scanning start direction of the light beam by the mirror control unit between the forward scanning direction and the backward scanning direction For each of the plurality of image carriers, and by controlling the writing control unit of each image carrier based on the determination result of the synchronization determination unit, the scanning start direction of the light beam by the mirror control unit is controlled by the image carrier while To provide an image forming apparatus and a control section for controlling the same direction.

  In order to solve the above-mentioned problems and achieve the object, the present invention provides a plurality of image carriers that rotate in the sub-scanning direction by oscillating a reflecting mirror that reflects a light beam emitted from a light source. A scanning process for reciprocating scanning of the light beam, a detection process for detecting the light beam by the optical sensors provided at both ends in the scanning direction of the plurality of image carriers, and a forward scanning or a backward scanning of the light beam detected by the optical sensor Image formation including a synchronization determination step for determining which is based on, and a control step for controlling the scanning start direction of the light beam in the same direction among a plurality of image carriers based on the determination result of the synchronization determination step An apparatus control method is provided.

  In order to solve the above-mentioned problems and achieve the object, the present invention provides a plurality of image carriers that rotate in the sub-scanning direction by oscillating a reflecting mirror that reflects a light beam emitted from a light source. A scanning step for reciprocating scanning of the light beam, a detection step for detecting the light beam by optical sensors provided at both ends in the scanning direction of the plurality of image carriers, and forward scanning or backward scanning of the light beam detected by the optical sensor The computer executes a synchronization determination step for determining which is due to, and a control step for controlling the scanning start direction of the light beam in the same direction among a plurality of image carriers based on the determination result of the synchronization determination step A control program for an image forming apparatus is provided.

  According to the present invention, since the reciprocating scanning of the light beam is executed in a unified manner in either the forward scanning or the backward scanning, it is possible to suppress deterioration of the image quality.

FIG. 1 is a schematic side view showing the overall configuration of a tandem type color image forming apparatus according to an embodiment of the present invention. FIG. 2 is a block diagram showing the configuration of the optical scanning device according to the embodiment of the present invention. FIG. 3 is a block diagram showing a configuration of a control system for unifying the laser light writing direction in the same direction between the image carriers. FIG. 4 is a flowchart showing the flow of processing for unifying the laser light writing direction in the same direction between the image carriers. FIG. 5 is a block diagram showing the configuration of a control system in the case of performing color misregistration correction by changing the oscillation phase of the reflecting mirror. FIG. 6 is a flowchart showing the flow of processing when color misregistration correction is performed by changing the oscillation phase of the reflecting mirror. FIG. 7 is a block diagram showing the configuration of a control system when color misregistration correction is performed by changing the rotation speed of the image carrier. FIG. 8 is a flowchart showing the flow of processing when color misregistration correction is performed by changing the rotation speed of the image carrier.

  Hereinafter, a configuration of a tandem type color image forming apparatus according to an embodiment of the present invention will be described with reference to the drawings. However, the present invention is not limited to a tandem type color image forming apparatus, and can be applied to all image forming apparatuses of a type in which toner images are transferred in an overlapping manner.

[Configuration of color image forming apparatus]
FIG. 1 is a schematic side view showing the overall configuration of a tandem type color image forming apparatus according to an embodiment of the present invention. As shown in FIG. 1, the color image forming apparatus 1 generally develops electrostatic latent images formed on the image carriers 2a, 2b, 2c, 2d by developing devices 5a, 5b, 5c, 5d. Then, the toner images formed are sequentially transferred onto the intermediate transfer belt B by the primary transfer devices 6a, 6b, 6c, and 6d, and the toner images on the intermediate transfer belt B are transferred onto the paper P by the secondary transfer device 9. This is an indirect transfer method that performs batch transfer.

  The intermediate transfer belt B is an endless belt and is stretched by a plurality of rollers. The intermediate transfer belt B is rotated at a constant speed by a motor connected to one of the rollers in the rotation direction (sub-scanning direction). Driven. On the upper side of the intermediate transfer belt B, image carriers 2a, 2b, 2c, and 2d for black, magenta, cyan, and yellow are arranged along the rotation direction of the intermediate transfer belt B (the arrow direction in the drawing). They are arranged in parallel. Photosensitive drums and photosensitive belts can be used as the image carriers 2a, 2b, 2c, and 2d. The image carriers 2a, 2b, 2c, and 2d are provided with a charging device 3a, 3b, 3c, and 3d, a developing device 5a, 5b, 5c, and 5d, a primary transfer device 6a, 6b, 6c, and 6d, and a blade. Cleaning devices 7a, 7b, 7c, and 7d configured by brushes and the like, and static elimination devices 8a, 8b, 8c, and 8d are provided, respectively.

  The primary transfer devices 6a, 6b, 6c, and 6d are disposed to face the image carriers 2a, 2b, 2c, and 2d with the intermediate transfer belt B interposed therebetween. That is, the intermediate transfer belt B is rotated while being sandwiched between the primary transfer devices 6a, 6b, 6c, 6d and the image carriers 2a, 2b, 2c, 2d. The image carriers 2a, 2b, 2c, 2d are rotationally driven in the rotational direction. At this time, the surfaces of the image carriers 2a, 2b, 2c, 2d are charged to a predetermined polarity by the charging devices 3a, 3b, 3c, 3d. The

  An electrostatic latent image is formed by irradiating the charged surfaces of the image carriers 2a, 2b, 2c, and 2d with a laser beam corresponding to an image signal from the optical scanning device 4. The image signal related to the laser light irradiation is an image signal input from the printer controller 25 (described later) to the optical scanning device 4 and is subjected to predetermined image processing by a writing control unit 26 (described later). The electrostatic latent images formed in this manner are developed into toner images of respective colors by the developing devices 5a, 5b, 5c, and 5d, and are visualized.

  The black, magenta, cyan and yellow toner images on the developed image carriers 2a, 2b, 2c and 2d are sequentially superimposed on the surface of the intermediate transfer belt B by the action of the primary transfer devices 6a, 6b, 6c and 6d. In this state, the image is transferred and a full-color composite color image is formed. The charged surfaces of the image carriers 2a, 2b, 2c, and 2d are discharged by the discharging devices 8a, 8b, 8c, and 8d after the remaining toner images are cleaned by the cleaning devices 7a, 7b, 7c, and 7d.

  The secondary transfer device 9 is disposed opposite to a roller that stretches the intermediate transfer belt B with the intermediate transfer belt B interposed therebetween. A sheet P fed from the sheet feeding unit is sent between the roller and the secondary transfer device 9 at a predetermined timing. When the paper P is fed between the roller and the secondary transfer device 9 in the paper transport direction (arrow direction in the figure), the composite color image carried on the intermediate transfer belt B is transferred by the secondary transfer device 9 to the paper P. Are collectively transferred. The composite color image on the paper P is fixed by heat and pressure by the fixing device 10 and discharged onto a paper discharge tray. The transfer residual toner adhering to the surface of the intermediate transfer belt B after the transfer of the composite color image is removed by the cleaning device 7e.

[Configuration of optical scanning device]
FIG. 2 is a block diagram showing a configuration of the optical scanning device 4. As shown in FIG. 2, the optical scanning device 4 includes an LD (Laser Diode) unit 11, a reflection mirror unit 12, and an optical member 13 for each image carrier 2 (2a, 2b, 2c, 2d). The LD unit 11 is composed of a laser diode and its drive circuit. The LD unit 11 irradiates the reflection mirror unit 12 with laser light corresponding to an image signal input from a writing control unit 26 described later. Specifically, the LD unit 11 irradiates the reflection mirror unit 12 with a light beam corresponding to an image signal by changing the lighting time or lighting interval of the laser diode, or the lighting and extinguishing timing.

  The reflection mirror unit 12 includes a swingable small reflection mirror such as a micro electro mechanical system (MEMS) or a galvanometer mirror and a mirror control unit (see FIG. 5) that controls the swing operation. The reflection mirror unit 12 reciprocally scans the surface of the image carrier 2 (2a, 2b, 2c, 2d) with the laser light L emitted from the LD unit 11 by swinging the reflection mirror. The reflection mirror unit 12 corresponds to the polarization unit according to the present invention. The optical member 13 corrects the laser beam reflected by the reflecting mirror so as to reciprocate in the main scanning direction at a constant speed with respect to the image carrier 2 (2a, 2b, 2c, 2d).

  The optical scanning device 4 includes synchronization sensors 21 and 22, a synchronization determination unit 23, a writing direction determination unit 24, a writing control unit 26, and a CPU (Central Processing Unit) 27 as its control system. The synchronization sensors 21, 22 are provided at both ends of the image carrier 2 (2a, 2b, 2c, 2d) in the main scanning direction. The synchronization sensors 21 and 22 output a synchronization signal every time the laser beam reflected by the reflection mirror unit 12 is received. The synchronous sensors 21 and 22 correspond to detection means according to the present invention. The synchronization determination unit 23 uses a method disclosed in, for example, Japanese Patent Application Laid-Open No. 2007-144800 every time a synchronization signal is output from the synchronization sensors 21 and 22, and lasers received by the synchronization sensors 21 and 22. It is determined whether the light is laser light during forward scanning or backward scanning. The synchronization determination unit 23 corresponds to the synchronization determination unit according to the present invention.

  The writing direction determining unit 24 controls the writing direction when performing image signal writing processing on the image carrier 2 (2a, 2b, 2c, 2d) between the forward scanning direction and the backward scanning direction. . The writing direction determination unit 24 corresponds to a control unit according to the present invention. The writing control unit 26 performs raster conversion on the two-dimensional image data transmitted from the printer controller 25, or an arbitrary writing clock so as to meet the main scanning width of the image carrier 2 (2a, 2b, 2c, 2d). The image signal is converted according to the signal. In addition, the writing control unit 26 determines the image on the image carrier 2 (2a, 2b, 2c, 2d) according to the writing direction determined by the writing direction determination unit 24 in accordance with the synchronization signals output from the synchronization sensors 21 and 22. The LD unit 11 is controlled to execute the signal writing process.

  The CPU 27 loads the control program stored in the ROM (not shown) into the RAM (not shown), and executes the control program loaded in the RAM, whereby the synchronization determination unit 23 and the writing direction determination. The operation of the unit 24, the write control unit 26, and the LD unit 11 is comprehensively controlled. The control program stored in the ROM is an installable or executable file that can be read by a computer such as a CD-ROM, flexible disk (FD), CD-R, or DVD (Digital Versatile Disk). The recording medium may be recorded and provided. The control program stored in the ROM may be stored on a computer connected to a network such as the Internet and provided by being downloaded via the network. The control program stored in the ROM may be provided or distributed via a telecommunication line such as the Internet.

  As shown in FIG. 3, the CPU 27 uses the determination results of the synchronization determination units 23a, 23b, 23c, and 23d of the image forming units A, B, C, and D including the image carriers 2a, 2b, 2c, and 2d, respectively. The writing direction determining units 24a, 24b, 24c, and 24d are controlled so that the writing direction of the image signal for each of the image carriers 2a, 2b, 2c, and 2d is the same between the image carriers 2a, 2b, 2c, and 2d. To do.

  The flowchart shown in FIG. 4 is a flowchart showing the flow of a writing direction control process for controlling the writing direction of each image carrier 2a, 2b, 2c, 2d. As shown in FIG. 4, first, the CPU 27 determines the determination results of the synchronization determination units 23a, 23b, 23c, and 23d of the image forming units A, B, C, and D including the image carriers 2a, 2b, 2c, and 2d, respectively. Referring to FIG. 4, it is determined whether the laser light received by the synchronous sensors 21a, 21b, 21c, 21d, 22a, 22b, 22c, and 22d is the forward scanning laser light or the backward scanning laser light (steps S1 to S4). . Then, according to the processing results of steps S1 to S4, the CPU 27 writes the image signals to the image carriers 2a, 2b, 2c, 2d so that the image signals are written in the same direction between the image carriers 2a, 2b, 2c, 2d. The direction determining units 24a, 24b, 24c, and 24d are controlled (step S5).

(Color shift correction)
FIG. 5 is a block diagram showing the configuration of a control system for performing color misregistration correction. As shown in FIG. 5, the color image forming apparatus 1 includes a color misregistration detection unit 33, a color misregistration correction unit 34, and a CPU 27 as a control system for performing color misregistration correction. The CPU 27 loads the control program stored in the ROM (not shown) into the RAM (not shown), and executes the control program loaded in the RAM, whereby the color misregistration detection unit 33 and the color drift are detected. The operation of the correction unit 34 is comprehensively controlled.

  The color misregistration detection unit 33 includes a light source 31 and a light receiving sensor 32 provided in the vicinity of the intermediate transfer belt B. The light source 31 irradiates the intermediate transfer belt B with light. The light receiving sensor 32 detects light reflected or diffused on the surface of the intermediate transfer belt B by the light emitted from the light source 31 to the intermediate transfer belt B. The color misregistration detection unit 33 detects the toner image formed on the intermediate transfer belt B based on the light received by the light receiving sensor 32, and calculates the color misregistration amount based on the detection result.

  The color misregistration correction unit 34 corrects the color misregistration amount detected by the color misregistration detection unit 33 through registration adjustment, magnification adjustment, or the like. Since the color misregistration amount calculation method and the correction method itself are known or well-known techniques as disclosed in, for example, Japanese Patent No. 3556349, detailed description thereof is omitted. As a method of correcting the color misregistration amount in the sub-scanning direction by adjusting the registration, correction in units of scanning lines as disclosed in Patent Document 1 can be considered. However, in the color image forming apparatus 1 of the present embodiment, as described above, since the writing direction is unified in the same direction among the image carriers 2a, 2b, 2c, and 2d, the color misregistration amount in the sub-scanning direction is corrected. In doing so, correction is required at least in units of two scanning lines. In order to perform correction in units of two scanning lines or less, the oscillation phases of the reflection mirror units 12a, 12b, 12c, and 12d are controlled by controlling the mirror control units 35a, 35b, 35c, and 35d as shown in FIG. A method of changing between the image carriers 2a, 2b, 2c, 2d is conceivable.

  Specifically, in this case, the mirror control units 35a, 35b, 35c, and 35d, according to the reference clock signal transmitted from the color misregistration correction unit 34, reflect mirror units 12a, 12b, 12c, The swing phase of 12d is changed. The flow of the above color misregistration correction processing is illustrated as a flowchart shown in FIG. That is, first, the CPU 27 detects the color misregistration amount using the color misregistration detection unit 33 (step S11), and uses the color misregistration correction unit 34 to swing the reflection mirror units 12a, 12b, 12c, and 12d. Is calculated (step S12). Then, the CPU 27 controls the mirror control units 35a, 35b, 35c, and 35d according to the amount of change calculated in the process of step S12, thereby changing the oscillation phase of the reflection mirror units 12a, 12b, 12c, and 12d to the image carrier 2a, It is changed between 2b, 2c, 2d (step S13).

  Instead of changing the oscillation phase of the reflection mirror units 12a, 12b, 12c, 12d, the rotational speed of the image carriers 2a, 2b, 2c, 2d is changed between the image carriers 2a, 2b, 2c, 2d. By doing so, color misregistration correction may be performed. A control system in this case is shown in FIG. As shown in FIG. 7, in this case, the image carrier control units 36a, 36b, 36c, and 36d that control the rotational speeds of the image carriers 2a, 2b, 2c, and 2d are the colors calculated by the color misregistration correction unit 34. The rotational speeds of the image carriers 2a, 2b, 2c, and 2d are changed according to the correction amount of deviation.

  The flow of the above color misregistration correction processing is illustrated as a flowchart shown in FIG. That is, first, the CPU 27 detects the color misregistration amount using the color misregistration detection unit 33 (step S21), and the color misregistration correction unit 34 determines the amount of change in the rotation speed of the image carrier 2a, 2b, 2c, 2d. Calculate (step S22). Then, the CPU 27 changes the rotational speed of the image carriers 2a, 2b, 2c, 2d by controlling the image carrier controllers 36a, 36b, 36c, 36d according to the change amount calculated by the process of step S22 (step S22). S23).

  As is apparent from the above description, in the tandem type color image forming apparatus 1 according to the embodiment of the present invention, the CPU 27 detects whether the light beam detected by the synchronization sensors 21 and 22 is based on the forward scanning or the backward scanning. Is determined for each of the image carriers 2a, 2b, 2c, and 2d, and the writing control unit 26 of each image carrier is controlled based on the determination result, whereby the scanning start direction of the light beam is determined by the image carrier. Control is performed in the same direction between 2a, 2b, 2c, and 2d. Therefore, according to the tandem type color image forming apparatus 1 according to the embodiment of the present invention, the skew angle of the light beam is different between the image carriers 2a, 2b, 2c, and 2d, so that the color is formed at the end of the color image. It is possible to prevent image quality from deteriorating due to misalignment or color unevenness.

  According to the tandem-type color image forming apparatus 1 according to the embodiment of the present invention, the CPU 27 reciprocally scans the light beam so that the electrostatic latent images formed on the surfaces of the image carriers 2a, 2b, 2c, and 2d. The amount of deviation between the image carriers 2a, 2b, 2c, and 2d is detected, and the oscillation phase of the reflection mirror unit 12 is changed between the image carriers 2a, 2b, 2c, and 2d based on the detected amount of deviation. Thus, it is possible to correct the amount of color misregistration in the sub-scanning direction and suppress deterioration in image quality.

  According to the tandem type color image forming apparatus according to the embodiment of the present invention, the CPU 27 reciprocally scans the light beam to form the electrostatic latent image formed on the surface of the image carrier 2a, 2b, 2c, 2d. The amount of deviation between the carrier 2a, 2b, 2c, 2d is detected, and the rotational speed of the image carrier 2a, 2b, 2c, 2d is detected between the image carrier 2a, 2b, 2c, 2d based on the detected amount of deviation. Therefore, it is possible to correct the amount of color misregistration in the sub-scanning direction and suppress deterioration in image quality.

  As mentioned above, although embodiment which applied the invention made | formed by this inventor was demonstrated, this invention is not limited with the description and drawing which make a part of indication of this invention by this embodiment. For example, in the present embodiment, an example of application to an indirect transfer type color image forming apparatus in which a color image is once formed on an intermediate transfer belt and transferred to a sheet at once by a secondary transfer apparatus has been described. The present invention can be similarly applied to a direct transfer type color laser printer that sequentially transfers a single color toner image formed thereon onto a transfer sheet that is a transfer body conveyed by a rotating body (conveyance belt). As described above, all other embodiments, examples, operation techniques, and the like made by those skilled in the art based on the above-described embodiments are all included in the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Color image forming apparatus 2a, 2b, 2c, 2d Image carrier 3a, 3b, 3c, 3d Charging device 4 Optical scanning device 5a, 5b, 5c, 5d Developing device 6a, 6b, 6c, 6d Primary transfer device 7a, 7b , 7c, 7d, 7e Cleaning devices 8a, 8b, 8c, 8d Neutralizing device 9 Secondary transfer device 10 Fixing device 11 LD unit 12, 12a, 12b, 12c, 12d Reflecting mirror unit 13 Optical members 21, 21a, 21b, 21c , 21d, 22, 22a, 22b, 22c, 22d Synchronization sensor 23, 23a, 23b, 23c, 23d Synchronization determination unit 24, 24a, 24b, 24c, 24d Write direction determination unit 25 Printer controller 26 Write control unit 27 CPU ( Central Processing Unit)
Reference Signs List 31 light source 32 light receiving sensor 33 color misregistration detection unit 34 color misregistration correction unit 35a, 35b, 35c, 35d mirror control unit 36a, 36b, 36c, 36d image carrier control unit A, B, C, D image forming unit

Japanese Patent No. 4199739

Claims (8)

A plurality of polarization means for reciprocally scanning the light beam;
A plurality of detecting means provided at both ends in the reciprocating scanning direction of the light beam for detecting the light beam reciprocally scanned by the polarizing means;
Synchronization determination means for determining for each of the plurality of polarization means whether the light beam detected by the detection means is based on forward scanning or backward scanning;
Control means for controlling the scanning start direction of the light beam in the same direction among a plurality of polarization means based on the determination result of the synchronization determination means;
An optical scanning device comprising: A swingable reflecting mirror that reflects the light beam emitted by the light source;
A mirror controller that reciprocally scans the light beam reflected by the reflection mirror on an image carrier that rotates in the sub-scanning direction by swinging the reflection mirror;
An optical sensor provided at both ends in the scanning direction of the image carrier for detecting the light beam;
A synchronization determination unit that determines whether the light beam detected by the optical sensor is based on forward scanning or backward scanning; and
A writing control unit for controlling the scanning start direction of the light beam by the mirror control unit between the forward scanning direction and the backward scanning direction;
For each of a plurality of image carriers,
A writing start direction for controlling the scanning start direction of the light beam by the mirror control unit in the same direction between the image carriers by controlling the writing control unit of each image carrier based on the determination result of the synchronization determining unit A control unit;
An image forming apparatus comprising: A color shift amount detection unit that detects a shift amount of a latent image formed on the surface of the image carrier by reciprocating the light beam between a plurality of image carriers;
A color misregistration correction unit that changes the oscillation phase of the reflection mirror between the image carriers based on the amount of misregistration detected by the color misregistration amount detection unit;
The image forming apparatus according to claim 2, further comprising: A color shift amount detection unit that detects a shift amount of a latent image formed on the surface of the image carrier by reciprocating the light beam between a plurality of image carriers;
A color misregistration correction unit that changes the rotational speed of the image carrier between the image carriers based on the amount of deviation detected by the color misregistration amount detection unit;
The image forming apparatus according to claim 2, further comprising: A scanning step of reciprocatingly scanning the light beam on the surface of the plurality of image carriers rotating in the sub-scanning direction by swinging a reflection mirror that reflects the light beam emitted from the light source;
A detection step of detecting a light beam by optical sensors provided at both ends in the scanning direction of the plurality of image carriers;
A synchronization determination step of determining whether the light beam detected by the optical sensor is based on forward scanning or backward scanning;
A writing direction control step of controlling the scanning start direction of the light beam in the same direction among the plurality of image carriers based on the determination result of the synchronization determination step;
A control method for an image forming apparatus. A color shift amount detection step of detecting a shift amount between a plurality of image carriers of a latent image formed on the surface of the image carrier by reciprocating scanning with the light beam;
A color misregistration correction step of changing a rocking phase of a reflection mirror between the image carriers based on a misregistration amount detected in the color misregistration amount detection step;
The image forming apparatus control method according to claim 5, further comprising: A color shift amount detection step of detecting a shift amount between a plurality of image carriers of a latent image formed on the surface of the image carrier by reciprocating scanning with the light beam;
A color misregistration correction step of changing the rotational speed of the image carrier based on the misregistration amount detected by the color misregistration amount detection step;
The image forming apparatus control method according to claim 5, further comprising: A scanning step of reciprocally scanning the light beam on the surface of the plurality of image carriers rotating in the sub-scanning direction by swinging a reflection mirror that reflects the light beam emitted from the light source;
A detection step of detecting a light beam by optical sensors provided at both ends in the scanning direction of the plurality of image carriers;
A synchronization determination step for determining whether the light beam detected by the optical sensor is based on forward scanning or backward scanning;
A writing direction control step of controlling the scanning start direction of the light beam in the same direction among the plurality of image carriers based on the determination result of the synchronization determination step;
A program for controlling an image forming apparatus for causing a computer to execute.

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