JP2008216519A - Optical scanner, method of optical scanning and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the deterioration of a light emitting part. <P>SOLUTION: One light emitting part is selected (s14) from 32 light emitting parts for serving as the light emitting part of an object to be adjusted after completing writing, light is emitted (driving signal) from the light emitting part of the object to be adjusted during the time (t2) from the completion of writing to the arrival of the scanning light to a scanning end, and the emitting light quantity of the light emitting part of the object to be adjusted is adjusted (s16) on the basis of the output signal of a light receiving element. Thus, all light emitting parts are turned off during the time from the end of scanning to the beginning of scanning and the temperature rise due to the heat generation from the light emitting parts is suppressed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical scanning device, an optical scanning method, and an image forming apparatus, and more particularly to an optical scanning device that scans a surface to be scanned with light, an optical scanning method, and an image forming apparatus including the optical scanning device.

  In electrophotographic image recording, an image forming apparatus using a laser is widely used. In this case, the image forming apparatus includes an optical scanning device, and forms a latent image by rotating the drum while scanning laser light using a polygon scanner (for example, a polygon mirror) in the axial direction of the photosensitive drum. Is common. In the field of electrophotography, an image forming apparatus is required to increase image density in order to improve image quality and to increase image output speed in order to improve operability.

  A method of simultaneously scanning a plurality of lines using a plurality of beams has been proposed.

  For example, Patent Document 1 discloses a light emitting element control device that automatically changes a drive current amount according to a change in the light output of the light emitting element by intermittently feeding back the light output amount of the light emitting element. . The light-emitting element control device includes a plurality of light-emitting elements that can be individually controlled from the outside, and an optical device that includes a light-receiving element that receives output light of the plurality of light-emitting elements and outputs a light intensity information signal to the outside, A light emitting element control means for controlling the amount of driving current of each light emitting element individually by intermittently and sequentially emitting light from each light emitting element inside the optical device and feeding back the light intensity information signal; The element control means executes the feedback control execution order of each light emitting element so that the light emitting element that is not the light emitting element that is closest to the light emitting element for which feedback control has been completed immediately before is always the light emitting element to be feedback controlled next time. Means for controlling the.

JP 2006-332142 A

  In recent years, an image forming apparatus has been used for simple printing as an on-demand printing system, and accordingly, an image forming apparatus with further stable image quality has been demanded.

  The present invention has been made under such circumstances, and a first object thereof is to provide an optical scanning device and an optical scanning method capable of suppressing deterioration of a light emitting unit.

  A second object of the present invention is to provide an image forming apparatus capable of stably forming a high quality image.

  According to a first aspect of the present invention, there is provided an optical scanning device that scans a surface to be scanned with light, a light source having a plurality of light emitting units; a deflector that deflects light from the light source; and the deflector An optical system for condensing the light deflected by the light onto the surface to be scanned; a sensor for detecting the scanning start of the surface to be scanned; a light receiving element for monitoring the amount of light from the light source; and the plurality of light emitting units At least one of the light emitting units is selected as a light emitting unit to be adjusted, and the timing from when scanning with light modulated in accordance with image information is completed until the scanning light reaches the end of scanning A light amount control device that emits light from the light emitting unit to be adjusted and adjusts the light emission amount of the light emitting unit to be adjusted based on the output signal of the light receiving element.

  According to this, at least one light-emitting part of the plurality of light-emitting parts is selected as the light-emitting part to be adjusted by the light quantity control device, and the scanning light after scanning with the light modulated according to the image information is completed. Light is emitted from the light emitting unit to be adjusted at a timing until the end of scanning reaches the end of scanning, and the light emission amount of the light emitting unit to be adjusted is adjusted based on the output signal of the light receiving element. In this case, it is possible to secure a time during which all of the plurality of light emitting units are turned off before the next scanning is started. Therefore, it is possible to suppress deterioration of the light emitting unit due to heat generation.

  According to a second aspect of the present invention, there is provided an optical scanning method for scanning a surface to be scanned with light from a plurality of light emitting units, wherein at least one light emitting unit among the plurality of light emitting units is light emission to be adjusted. A step of selecting as a unit; light is emitted from the light emitting unit to be adjusted at a timing from when scanning with light modulated in accordance with image information is completed until scanning light reaches the end of scanning And an optical scanning method.

  According to this, at least one light emitting unit among the plurality of light emitting units is selected as the light emitting unit to be adjusted, and after the scanning with the light modulated in accordance with the image information is completed, the scanning light is the end of the scanning. Light is emitted from the light-emitting unit to be adjusted at a timing until it reaches. In this case, it is possible to secure a time during which all of the plurality of light emitting units are turned off before the next scanning is started. Therefore, it is possible to suppress deterioration of the light emitting unit due to heat generation.

  According to a third aspect of the present invention, there is provided at least one image carrier; and at least one optical scanning device according to the invention that scans the at least one image carrier with light including image information. An image forming apparatus provided.

  According to this, since at least one optical scanning device of the present invention is provided, as a result, a high-quality image can be stably formed.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a schematic configuration of a laser printer 1000 as an image forming apparatus according to an embodiment of the present invention.

  The laser printer 1000 includes an optical scanning device 1010, a photosensitive drum 1030, a charging charger 1031, a developing roller 1032, a transfer charger 1033, a static elimination unit 1034, a cleaning blade 1035, a toner cartridge 1036, a paper supply roller 1037, a paper supply tray 1038, A registration roller pair 1039, a fixing roller 1041, a paper discharge roller 1042, a paper discharge tray 1043, and the like are provided.

  The charging charger 1031, the developing roller 1032, the transfer charger 1033, the charge removal unit 1034, and the cleaning blade 1035 are each arranged in the vicinity of the surface of the photosensitive drum 1030. Then, with respect to the rotation direction of the photosensitive drum 1030, the charging charger 1031 → the developing roller 1032 → the transfer charger 1033 → the charge eliminating unit 1034 → the cleaning blade 1035 are arranged in this order.

  A photosensitive layer is formed on the surface of the photosensitive drum 1030. That is, the surface of the photoconductor drum 1030 is a scanned surface. Here, the photosensitive drum 1030 rotates clockwise (in the direction of the arrow) within the plane in FIG.

  The charging charger 1031 uniformly charges the surface of the photosensitive drum 1030.

  The optical scanning device 1010 irradiates the surface of the photosensitive drum 1030 charged by the charging charger 1031 with light modulated based on image information from a host device (for example, a personal computer). As a result, a latent image corresponding to the image information is formed on the surface of the photosensitive drum 1030 on the surface of the photosensitive drum 1030. The latent image formed here moves in the direction of the developing roller 1032 as the photosensitive drum 1030 rotates. The configuration of the optical scanning device 1010 will be described later.

  The toner cartridge 1036 stores toner, and the toner is supplied to the developing roller 1032.

  The developing roller 1032 causes the toner supplied from the toner cartridge 1036 to adhere to the latent image formed on the surface of the photosensitive drum 1030 to visualize the image information. Here, the latent image to which the toner is attached (hereinafter also referred to as “toner image” for convenience) moves in the direction of the transfer charger 1033 as the photosensitive drum 1030 rotates.

  Recording paper 1040 is stored in the paper feed tray 1038. A paper feed roller 1037 is disposed in the vicinity of the paper feed tray 1038, and the paper feed roller 1037 takes out the recording paper 1040 one by one from the paper feed tray 1038 and conveys it to the registration roller pair 1039. The registration roller pair 1039 is disposed in the vicinity of the transfer roller 911, temporarily holds the recording paper 1040 taken out by the paper feeding roller 1037, and the recording paper 1040 is synchronized with the rotation of the photosensitive drum 1030. It is sent out toward the gap between 1030 and the transfer charger 1033.

  A voltage having a polarity opposite to that of the toner is applied to the transfer charger 1033 in order to electrically attract the toner on the surface of the photosensitive drum 1030 to the recording paper 1040. With this voltage, the toner image on the surface of the photosensitive drum 1030 is transferred to the recording paper 1040. The recording sheet 1040 transferred here is sent to the fixing roller 1041.

  In the fixing roller 1041, heat and pressure are applied to the recording paper 1040, whereby the toner is fixed on the recording paper 1040. The recording paper 1040 fixed here is sent to the paper discharge tray 1043 via the paper discharge roller 1042 and is sequentially stacked on the paper discharge tray 1043.

  The neutralization unit 1034 neutralizes the surface of the photosensitive drum 1030.

  The cleaning blade 1035 removes toner (residual toner) remaining on the surface of the photosensitive drum 1030. The removed residual toner is used again. The surface of the photosensitive drum 1030 from which the residual toner has been removed returns to the position of the charging charger 1031 again.

  Next, the configuration of the optical scanning device 1010 will be described. In this specification, the main scanning direction will be described as the Y-axis direction, the sub-scanning direction as the Z-axis direction, and the direction orthogonal to these will be described as the X-axis direction.

  As shown in FIG. 2, the optical scanning device 1010 includes a light source unit 1011, a cylindrical lens 1012, a half mirror 1013, a light receiving element 1014, a polygon mirror 1015, an fθ lens 1016, a toroidal lens 1017, a bending mirror 1018, and a synchronization sensor 1019. And the control apparatus 1020 which controls each said part collectively is provided.

  The light source unit 1011 includes a light source (referred to as a light source LA) having a plurality of light emitting units, a light source drive circuit (referred to as a light source drive circuit 400) for driving the light source LA, and a coupling lens (referred to as a coupling lens CL). Yes. Here, as shown in FIG. 3 as an example, the light source LA has a two-dimensional array of vertical cavity surface emitting semiconductor lasers (VCSEL) in which 32 light emitting portions are formed on one substrate. Yes.

  This two-dimensional array is a direction inclined by an angle θ from a direction corresponding to the main scanning direction (hereinafter also referred to as “M direction” for convenience) to a direction corresponding to the sub-scanning direction (here, the Z-axis direction). (Hereinafter, for convenience, it is referred to as “T direction”), there are four light emitting part rows in which eight light emitting parts are arranged at equal intervals. These four light emitting unit rows are arranged at equal intervals in the Z-axis direction. That is, the 32 light emitting units are two-dimensionally arranged along the T direction and the Z axis direction. Here, for the sake of convenience, the first light emitting unit row, the second light emitting unit row, the third light emitting unit row, and the fourth light emitting unit row are referred to from the top to the bottom in FIG. In the present specification, the “light emitting portion interval” refers to the distance between the centers of two light emitting portions.

  Further, in order to identify each light emitting unit, for convenience, as shown in FIG. 4, the eight light emitting units constituting the first light emitting unit row are denoted by v1 to v8 from the upper left to the lower right in FIG. The eight light emitting units constituting the second light emitting unit row are v9 to v16, the eight light emitting units constituting the third light emitting unit row are v17 to v24, and the eight light emitting units constituting the fourth light emitting unit row. V25 to v32.

  As shown in FIG. 5, the light source drive circuit 400 individually drives the 32 light emitting units based on various drive information from the control device 1020.

  The coupling lens CL makes light from the light source LA substantially parallel light. Therefore, substantially parallel light is output from the light source unit 1011.

  Returning to FIG. 2, the cylindrical lens 1012 condenses the light from the light source unit 1011 in the vicinity of the deflection surface of the polygon mirror 1015 in the sub-scanning direction.

  The half mirror 1013 is disposed on the optical path between the cylindrical lens 1012 and the polygon mirror 1015, and reflects part of the light that passes through the cylindrical lens 1012. The ratio of the amount of transmitted light and reflected light in the half mirror 1013 is set to any of 9: 1, 8: 2, and 7: 3.

  The polygon mirror 1015 is made of a regular hexagonal columnar member having a low height, and six deflection reflection surfaces are formed on the side surface. Then, it is rotated at a constant angular velocity in the direction of the arrow shown in FIG. 2 by a rotation mechanism (not shown). Therefore, the light emitted from the light source unit 1011 and condensed near the deflection reflection surface of the polygon mirror 1015 by the cylindrical lens 1012 is deflected at a constant angular velocity by the rotation of the polygon mirror 1015.

  The fθ lens 1016 has an image height proportional to the incident angle of light from the polygon mirror 1015, and an image plane of light (hereinafter also referred to as “scanning light” for convenience) deflected by the polygon mirror 1015 at a constant angular velocity. Move at a constant speed in the main scanning direction.

  The light transmitted through the fθ lens 1016 forms an image on the surface of the photosensitive drum 1030 via the toroidal lens 1017 and the bending mirror 1018.

  As an example, as shown in FIG. 6, the image plane of the scanning light moves from the scanning start end toward the scanning end as the polygon mirror 1015 rotates. Note that the effective scanning area in FIG. 6 is an area where writing is performed according to image data. When the image plane of the scanning light reaches the scanning end, it returns to the scanning start end for the next scanning.

  The synchronization sensor 1019 is equivalent to the image plane, is arranged at a position where light before the start of scanning reflected by the bending mirror 1018 is incident, and outputs a signal (photoelectric conversion signal) corresponding to the amount of received light. Therefore, the start of scanning on the photosensitive drum 1030 can be detected from the output signal of the synchronous sensor sensor 1019.

  The light receiving element 1014 is disposed on the optical path of the light reflected by the half mirror 1013, and outputs a signal (photoelectric conversion signal) corresponding to the amount of received light.

  The control device 1020 includes a reference clock generation circuit 402, a pixel clock generation circuit 405, an image processing circuit 407, a light source selection circuit 414, a timing signal generation circuit 415, and a light amount adjustment circuit 416, as shown in FIG. . Note that the arrows in FIG. 7 indicate the flow of typical signals and information, and do not represent the entire connection relationship of each block.

  FIG. 8 shows a timing chart related to each circuit. Here, s19 is an output signal of the synchronous sensor 1019, s15 is an output signal of the timing signal generation circuit 415, s14 is an output signal of the light source selection circuit 414, and s16 is an output signal of the light amount adjustment circuit 416.

  The image processing circuit 407 creates write data for each light emitting unit based on image information from the host device. This write data is supplied to the light source drive circuit 400 as one of the drive information at a predetermined timing.

  The reference clock generation circuit 402 generates a reference high frequency clock signal.

  The pixel clock generation circuit 405 generates a pixel clock signal based on the output signal s19 of the synchronous sensor 1019 and the high frequency clock signal from the reference clock generation circuit 402. The pixel clock signal generated here is supplied to the light source driving circuit 400 as one of the driving information.

  The timing signal generation circuit 415 changes the output signal s15 from a low level to a high level when a preset time t1 elapses after the output signal s19 of the synchronous sensor 1019 rises. When the preset time t2 elapses, the output signal s15 is changed from the high level to the low level. The output signal of the timing signal generation circuit 415 is supplied to the light source driving circuit 400 as one of the driving information.

  The time t1 corresponds to the time from the start of scanning until the scanning with light modulated in accordance with the image information (hereinafter also referred to as “writing” for convenience) is completed and the output of the light source selection circuit 414 is stabilized. . The time t2 corresponds to the time until the image plane of the scanning light reaches the scanning end from the position of the time t1.

  The light source selection circuit 414 selects a light emitting unit based on write data for each light emitting unit immediately before and during writing, and outputs a signal designating the selected light emitting unit.

  When the writing is completed, the light source selection circuit 414 selects one of the 32 light emitting units as a light emitting unit to be adjusted, and outputs a signal designating the light emitting unit to be adjusted. Here, as an example, the light source selection circuit 414 selects the light emitting unit to be adjusted from the light emitting units excluding the light emitting unit used immediately before and the light emitting unit adjacent to the light emitting unit. For example, if the light emitting unit used immediately before is v2, v1 to v3 are excluded.

  Furthermore, when the image plane of the scanning light reaches the scanning end, the light source selection circuit 414 selects one light emitting unit used for detecting the start of the next scanning from the 32 light emitting units, and the selected light emission. Outputs a signal specifying the part. Here, as an example, the light emitting unit used in the next scanning is selected from the light emitting units excluding the light emitting unit first used and the light emitting unit adjacent to the light emitting unit. For example, if the light emitting unit that is first used in the next scan is v3, v2 to v4 are excluded.

  The output signal s14 of the light source selection circuit 414 is supplied to the light source drive circuit 400 as one of the drive information.

  When the output signal s15 of the timing signal generation circuit 415 becomes high level, the light amount adjustment circuit 416 generates a signal for adjusting the light emission amount of the light emitting unit to be adjusted based on the output signal of the light receiving element 1014. The output signal s16 of the light amount adjustment circuit 416 is supplied to the light source drive circuit 400 as one of the drive information. Thereby, in the light source drive circuit 400, the drive signal (drive current) of the light emitting unit to be adjusted is adjusted.

  As is clear from the above description, in the optical scanning device 1010 according to the present embodiment, the control device 1020 implements the optical scanning method of the present invention.

  As described above, the optical scanning device 1010 according to the present embodiment includes the control device 1020 including the light source selection circuit 414, the timing signal generation circuit 415, and the light amount adjustment circuit 416, and includes the 32 light emitting units. One light-emitting unit is selected as a light-emitting unit to be adjusted, and the adjustment target is at a timing from when scanning with light modulated in accordance with image information ends until scanning light reaches the end of scanning. The light is emitted from the light emitting unit, and the light emission amount of the light emitting unit to be adjusted is adjusted based on the output signal of the light receiving element 1014. Accordingly, all the light emitting units can be turned off from the scanning end to the scanning start end, and a temperature increase due to heat generation of the light emitting units can be suppressed. As a result, deterioration of the light emitting unit is suppressed.

  In addition, the laser printer 1000 according to the present embodiment includes the optical scanning device 1010 that can suppress the deterioration of the light emitting unit, and thus can stably form a high-quality image.

  In the above embodiment, the light source selection circuit 414 selects the light emitting unit to be adjusted from among the light emitting units excluding the light emitting unit used immediately before and the light emitting unit adjacent to the light emitting unit among the 32 light emitting units. Although the case of selecting has been described, the present invention is not limited to this. For example, the light source selection circuit 414 may select the light emitting unit to be adjusted from light emitting units other than the light emitting unit used for detection of the next scan start and the light emitting unit adjacent to the light emitting unit. As an example, as shown in FIG. 9, the light emitting unit to be adjusted is selected as v1 → v3 → v5 →... → v31 → v2 → v4 → v6 →. May be.

  Further, in the above-described embodiment, the case where the light amount adjustment of one light emitting unit is performed at the timing from when writing is completed until the scanning light reaches the end of scanning is described, but the present invention is not limited thereto. The light quantity adjustment of the plurality of light emitting units may be performed at the above timing. In this case, it is preferable to shift the light emission timing of each light emitting unit so that the plurality of light emitting units do not emit light simultaneously. As an example, FIG. 10 shows a timing chart in the case where the light amount adjustment of the two light emitting units is performed at the timing from when the writing is completed to when the scanning light reaches the end of scanning.

  Moreover, although the said embodiment demonstrated the case where a light source has 32 light emission parts, it is not limited to this, What is necessary is just to have a some light emission part. The array of the plurality of light emitting units may be a one-dimensional array.

  In the above-described embodiment, at least one of the light source selection circuit 414 and the timing signal generation circuit 415 may be replaced with a microcomputer that executes similar processing according to a program.

  In the above embodiment, the laser printer 1000 is described as the image forming apparatus. However, the present invention is not limited to this. In short, an image forming apparatus including the optical scanning device 1010 can form a high quality image at high speed.

  Further, the image forming apparatus may include the optical scanning device 1010 and directly irradiate a laser beam onto a medium (for example, paper) that develops color with laser light.

  Further, an image forming apparatus using a silver salt film as the image carrier may be used. In this case, a latent image is formed on the silver salt film by optical scanning, and this latent image can be visualized by a process equivalent to a developing process in a normal silver salt photographic process. Then, it can be transferred to photographic paper by a process equivalent to a printing process in a normal silver salt photographic process. Such an image forming apparatus can be implemented as an optical plate making apparatus or an optical drawing apparatus that draws a CT scan image or the like.

  As an example, as shown in FIG. 11, the image forming apparatus may be a tandem color machine corresponding to a color image and including a plurality of photosensitive drums. The tandem color machine includes a black (K) photosensitive drum K1, a charger K2, a developing device K4, a cleaning unit K5, a transfer charging unit K6, a cyan (C) photosensitive drum C1, and a charger. C2, developing unit C4, cleaning unit C5, transfer charging unit C6, magenta (M) photosensitive drum M1, charging unit M2, developing unit M4, cleaning unit M5, transfer charging unit M6, yellow A photosensitive drum Y1 for (Y), a charger Y2, a developing device Y4, a cleaning unit Y5, a transfer charging unit Y6, an optical scanning device 1010, a transfer belt 80, a fixing unit 30 and the like are provided.

  In this case, the optical scanning device 1010 includes a light emitting unit for black, a light emitting unit for cyan, a light emitting unit for magenta, and a light emitting unit for yellow.

  The light from the black light emitting unit is irradiated to the photosensitive drum K1 via the black scanning optical system, and the light from the cyan light emitting unit is irradiated to the photosensitive drum C1 through the cyan scanning optical system. The light from the light emitting unit for magenta is irradiated to the photosensitive drum M1 through the scanning optical system for magenta, and the light from the light emitting unit for yellow is irradiated to the photosensitive member through the scanning optical system for yellow. The drum Y1 is irradiated. Note that an optical scanning device 1010 may be provided for each color.

  Each photosensitive drum rotates in the direction of the arrow in FIG. 11, and a charger, a developer, a transfer charging unit, and a cleaning unit are arranged in the order of rotation. Each charger uniformly charges the surface of the corresponding photosensitive drum. The surface of the photosensitive drum charged by the charger is irradiated with light by the optical scanning device 1010, and an electrostatic latent image is formed on the photosensitive drum. Then, a toner image is formed on the surface of the photosensitive drum by the corresponding developing device. Further, the toner images of the respective colors are transferred onto the recording paper by the corresponding transfer charging means, and finally the image is fixed on the recording paper by the fixing means 30.

  As described above, according to the optical scanning device and the optical scanning method of the present invention, it is suitable for suppressing deterioration of the light emitting section. The image forming apparatus of the present invention is suitable for stably forming a high quality image.

It is a figure for demonstrating schematic structure of the laser printer which concerns on one Embodiment of this invention. It is a figure for demonstrating schematic structure of the optical scanning device in FIG. It is a figure for demonstrating the light source of the light source unit in FIG. It is a figure for demonstrating the code | symbol provided to each light emission part of the light source. It is a figure for demonstrating the light source drive circuit of a light source unit. It is a figure for demonstrating a scanning start end and a scanning end. It is a block diagram of the control apparatus in FIG. It is a timing chart for demonstrating operation | movement of a control apparatus. It is a figure for demonstrating an example of the selection order of the light emission part used as the object of light quantity adjustment. It is a timing chart for demonstrating the case where two light emission parts used as the object of light quantity adjustment are selected. It is a figure for demonstrating schematic structure of a tandem color machine.

Explanation of symbols

  412 ... Light source drive circuit (part of adjustment circuit, drive circuit), 414 ... Light source selection circuit (selection circuit), 415 ... Timing signal generation circuit, 416 ... Light quantity adjustment circuit (part of adjustment circuit), 1000 ... Laser printer (Image forming apparatus) 1010 ... Optical scanning device, 1014 ... Light receiving element, 1015 ... Polygon mirror (deflector), 1016 ... fθ lens (part of optical system), 1017 ... Toroidal lens (part of optical system), 1018 ... Folding mirror (a part of the optical system), 1019 ... Synchronization sensor (sensor), 1030 ... Photosensitive drum (image carrier).

Claims (11)

An optical scanning device that scans a surface to be scanned with light,
A light source having a plurality of light emitting portions;
A deflector for deflecting light from the light source;
An optical system for condensing the light deflected by the deflector onto the surface to be scanned;
A sensor for detecting the start of scanning of the surface to be scanned;
A light receiving element for monitoring the amount of light from the light source;
At least one of the plurality of light emitting units is selected as the light emitting unit to be adjusted, and after the scanning with the light modulated according to the image information is finished, the scanning light reaches the end of the scanning A light amount control device that emits light from the light emitting unit to be adjusted at a timing between and adjusts the light emission amount of the light emitting unit to be adjusted based on the output signal of the light receiving element. . The light quantity control device includes:
A selection circuit for selecting the light emitting unit to be adjusted and the light emitting unit used for detecting the start of scanning;
A timing signal generation circuit for generating a timing signal indicating the light emission timing of the light emitting unit to be adjusted;
A drive circuit for driving the light emitting unit to be adjusted based on an output signal of the selection circuit and an output signal of the timing signal generation circuit;
The optical scanning device according to claim 1, further comprising: an adjustment circuit that adjusts a light emission amount of the light emitting unit to be adjusted based on an output signal of the light receiving element.   The selection circuit selects the light emitting unit to be adjusted from a light emitting unit excluding the light emitting unit used immediately before and the light emitting unit adjacent to the light emitting unit among the plurality of light emitting units. The optical scanning device according to claim 2.   The selection circuit selects the light emitting unit to be adjusted from the light emitting units used for detecting the next start of scanning and the light emitting units adjacent to the light emitting unit among the plurality of light emitting units. The optical scanning device according to claim 2.   The selection circuit is configured to select a light emitting unit to be used for detection of a next scanning start, a light emitting unit excluding the light emitting unit first used in the next scan and the light emitting unit adjacent to the light emitting unit among the plurality of light emitting units. The optical scanning device according to claim 2, wherein the optical scanning device is selected from the inside. The selection circuit selects a plurality of light emitting units as the light emitting unit to be adjusted,
6. The optical scanning according to claim 2, wherein the driving circuit drives each light emitting unit individually at different timings so that the selected plurality of light emitting units do not emit light simultaneously. apparatus. An optical scanning method for scanning a surface to be scanned with light from a plurality of light emitting units,
Selecting at least one light emitting unit among the plurality of light emitting units as a light emitting unit to be adjusted;
A step of emitting light from the light emitting unit to be adjusted at a timing from when scanning with light modulated in accordance with image information is completed until scanning light reaches the end of scanning. Scanning method.   In the selecting step, the light emitting unit to be adjusted is selected from among the plurality of light emitting units, the light emitting unit excluding the light emitting unit used immediately before and the light emitting unit adjacent to the light emitting unit. The optical scanning method according to claim 7.   In the selecting step, the light emitting unit to be adjusted is selected from among the plurality of light emitting units, excluding the light emitting unit used for detection of the next scanning start and the light emitting unit adjacent to the light emitting unit. The optical scanning method according to claim 7. At least one image carrier;
An image forming apparatus comprising: at least one optical scanning device according to claim 1 that scans the at least one image carrier with light including image information.   The image forming apparatus according to claim 10, wherein the image information is multicolor image information.

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