JP5223306B2 - Light beam scanning apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to a light beam scanning apparatus and an image forming apparatus that simultaneously drive a plurality of semiconductor lasers and simultaneously perform optical writing on a plurality of lines.

  In an image forming apparatus using a semiconductor laser, an image is formed by scanning a photoconductor with a light beam and exposing image information. For this reason, unless the amount of light on the photosensitive member is always kept constant, the formed image becomes darker or thinner than the desired image, or uneven density is caused. Therefore, normally, the light beam used for image formation is an APC (Auto power control) that keeps the light amount constant based on the initialization operation for detecting the characteristics of the semiconductor laser and the characteristic value obtained by the initialization operation. ) By performing the control, the light quantity of the light beam output from the semiconductor laser is controlled to be constant. However, in a semiconductor laser having a plurality of light emitting elements and capable of outputting a plurality of beams, one beam is weakly emitted (offset emission) while one beam is being initialized and APC controlled. Therefore, since the light emission is picked up, the initialization and the APC operation with high accuracy cannot be performed. This is because a light amount decrease with time called droop occurs unless a bias current is supplied and offset light is emitted even in a beam that is not emitting light.

For example, in Patent Document 1, a write control ASIC (Application ASIC) that controls the presence / absence of a bias current of a semiconductor laser having a plurality of light sources in order to remove the influence of offset emission of other channels (channels) of the semiconductor laser having a plurality of beams. Specific Integrated Circuit). This write control ASIC lights up each channel one by one and controls it to the desired light quantity sequentially while controlling the light emission other than the ch whose light quantity is adjusted to be offset. However, in this method, the channel emitting offset light is completely extinguished, and there is a concern about fluctuation of LD (Laser Diode) characteristic value due to heat. In other words, when adjusting the amount of light, adjustment is performed without offset light emission, but when writing an actual image, writing is performed with offset light emission, so there is a temperature difference due to the difference in the amount of heat generated by the LD. There is a possibility that the characteristics of the LD are different at the time of writing.
JP-A-2005-193452

  The present invention has been made in view of the above circumstances. When a semiconductor laser that emits a plurality of beams is used, the offset emission of other channels is not affected without completely turning off the offset emission of other channels. An object of the present invention is to provide a light beam scanning apparatus and an image forming apparatus which correct the light quantity output from the semiconductor laser to be constant.

In order to achieve such an object, a first light beam scanning apparatus of the present invention includes a light beam generating means having a plurality of light emitting elements and one light receiving element, and a light source control means for controlling lighting of the plurality of light emitting elements. When the light source control unit performs light amount adjustment control on one of the plurality of light emitting elements of the light beam generating unit, the light source scanning unit includes a light emitting element other than the one light emitting element. Correction means for correcting the influence of the weak light emission, and the correction means measures the weak light emission amount of the light emitting elements other than the light emitting elements on which the light quantity adjustment control is performed before the light source control means performs the light quantity adjustment control. The light amount adjustment control is corrected according to the measured weak light emission amount, and the current corresponding to the weak light emission amount measured in advance is subtracted from the current of the light receiving element when the light amount adjustment control is performed. Controlled to be the target amount set in advance weak quantity of light from the light emitting element other than the element, it characterized that you correct the light amount adjustment control in accordance with the target quantity.

According to a second light beam scanning device of the present invention, in the first light beam scanning device of the present invention, the correction means applies a current corresponding to a preset target light amount when the light amount adjustment control is performed. characterized Rukoto subtracted from the current.

The image forming apparatus of the present invention is the first or feature that you mount the second optical beam scanning apparatus of the present invention.

  According to the present invention, since the device for correcting weak light emission other than the light source for which the light amount adjustment control is performed is provided, it is possible to perform the light amount adjustment with high accuracy.

  The best mode for carrying out the present invention will be described below in detail with reference to the accompanying drawings.

  FIG. 1 shows an example of the configuration of the image forming apparatus of the present invention. The image forming apparatus of the present invention is a color image forming apparatus called a tandem type in which a plurality of image forming units are arranged along a conveying belt.

  Image forming portions A that form images of different colors (yellow: Y, magenta: M, cyan: C, black: K) are arranged along the transport belt 2 that transports the transfer paper 1. The conveying belt 2 is constructed by conveying rollers 3 and 4, one of which is a driving roller that is driven and rotated, and the other is a driven roller that is driven and rotated, and is rotated in the direction of the arrow by the rotation of the conveying rollers 3 and 4. A paper feed tray 5 in which the transfer paper 1 is stored is provided below the conveyance belt 2. The transfer sheet at the uppermost position among the stored transfer sheets 1 is fed at the time of image formation, is timed with each unit by the registration sensor 14 and is adsorbed onto the transport belt 2 by electrostatic adsorption. The adsorbed transfer sheet 1 is conveyed to the first image forming unit (yellow), where yellow image formation is performed. The first image forming unit (yellow) includes a photosensitive drum 6Y, a charger 7Y disposed around the photosensitive drum 6Y, an exposure device (light beam scanning device / optical writing device) 8, a developing device 9Y, It is composed of a photoreceptor cleaner 10Y. The surface of the photosensitive drum 6Y is uniformly charged by the charger 7Y, and then exposed by the exposure device 8 with a laser beam (light beam) 11Y corresponding to a yellow image, thereby forming an electrostatic latent image. The formed electrostatic latent image is developed by the developing device 9Y, and a toner image is formed on the photosensitive drum 6Y. This toner image is transferred by the transfer device 12Y at a position (transfer position) where the photosensitive drum 6Y and the transfer belt 1 are in contact with the transfer belt 1, and a single color (yellow) image is formed on the transfer paper 1. In the photoreceptor drum 6Y after the transfer, unnecessary toner remaining on the surface is cleaned by the photoreceptor cleaner 10Y to prepare for the next image formation. As described above, the transfer paper 1 on which the single color (yellow) is transferred by the first image forming unit (yellow) is transported to the second image forming unit (magenta) by the transport belt 2. Here, as in the case of yellow, the toner image (magenta) formed on the photosensitive drum 6M is transferred onto the transfer paper 1 in an overlapping manner. The transfer paper 1 is further conveyed sequentially to the third image forming unit (cyan) and the fourth image forming unit (black). As in the case of yellow and magenta, the formed toner image is transferred to the transfer paper 1 to form a color image. The transfer paper 1 on which the four color images are formed after passing through the fourth image forming portion (black) is peeled off from the conveying belt 2 and fixed by the fixing device 13, and then the outside of the image forming apparatus. Is discharged.

  FIG. 2 shows an optical unit in the light beam scanning apparatus (exposure unit 8 in FIG. 1) of the present invention. FIG. 2 is a top view of the light beam scanning apparatus.

  Light beams (laser light) necessary for image formation are LD control board_BK53, LD control board_Y54, and LD control board_C52 existing in the LD unit BK31, LD unit Y32, LD unit C42, and LD unit M43. , Output from the LD mounted on each LD control board_M55.

  The light beams from the LD unit BK31 and the LD unit Y32 pass through the cylinder lenses CYL_BK33 and CYL_Y34, enter the lower surface of the polygon mirror 37 by the reflection mirror BK35 and the reflection mirror Y36, and are deflected by the rotation of the polygon mirror 37, and fθ. The lens passes through the lens BKC38 and the fθ lens YM39 and is folded back by the first mirror BK40 and the first mirror Y41.

  On the other hand, the light beams from the LD unit C42 and the LD unit M43 pass through CYL_C44 and CYL_M45, enter the upper surface of the polygon mirror 37, and are deflected by the rotation of the polygon mirror 37, and pass through the fθ lens BKC38 and the fθ lens YM39. On the other hand, it is folded by the first mirror C46 and the first mirror M47.

  Cylinder mirrors CYM_BKC48 and CYM_YM49, as well as sensor BKC50 and sensor YM51 are provided upstream of the writing position in the main scanning direction (B of first mirror Y41, C of first mirror BK40), and fθ lens BKC38 and fθ lens. The light beam that has passed through YM39 is reflected and collected by CYM_BKC48 and CYM_YM49, and is incident on sensor BKC50 and sensor YM51. These sensors BKC50 and sensor YM51 are synchronization detection sensors for synchronizing in the main scanning direction.

  In addition, the light beams from the LD unit BK31 and the LD unit C32 use a common CYM_BKC48 and sensor BKC50. The same applies to the LD unit Y32 and the LD unit M43. Since two color light beams are incident on the same sensor, the timing at which each light beam is incident on the sensor can be changed by changing the incident angles of the light beams of the respective colors to the polygon mirror 37. It is output in series as a pulse train. As can be seen from FIG. 2, BK and C and Y and M are scanned in the reverse direction.

  In an image forming apparatus using an LD, scanning is performed by turning on / off an LD according to image information while scanning a photosensitive member with a light beam. Therefore, it is necessary to keep the light quantity on the photoconductor constant according to the photoconductor sensitivity. The light beam normally used for image formation performs an initialization operation for detecting the characteristics of the LD and APC (Auto power control) control for keeping the light quantity constant based on the characteristic value obtained by the initialization operation. Control is performed to keep the amount of light output from the LD constant. The initialization operation is performed immediately before the LD is turned on for image formation, and the APC operation includes a line APC performed outside the image area for each line scan and an initialization APC performed during the initialization operation. The basic operation of the light beam scanning apparatus will be described with reference to the flow of FIG. LD initialization (including initialization APC) is performed (step S1). One line scanning is performed (step S2), and line APC is performed (step S3). It is determined whether or not the scanning is finished (step S4). When the scanning is not finished (step S4 / NO), the process returns to step S2, and when the scanning is finished (step S4 / YES), the process is finished.

  Next, a basic configuration of a light beam scanning apparatus using a semiconductor laser element having a plurality of light sources (hereinafter referred to as an LD array) will be described with reference to FIG.

  As shown in FIG. 4, the light beam scanning device includes, as a basic configuration, a scanner unit 20 that reads an image, a writing control unit 21 that performs writing control according to image data read by the scanner unit 20, and an LD array 23. LD control unit (light source control means) 22 that performs lighting control and initialization, APC operation, control unit 24 that controls each of the above units (CPU: Central Processing Unit, ROM: Read Only Memory, RAM: Random Access Memory, other memory) Etc.). Further, as shown in FIG. 4, the LD array (light beam generating means) 23 has a structure of one light receiving element (PD: Photo Diode; light amount detecting element) for a plurality of light emitting elements (LD: Laser Diode). FIG. 4 is a diagram showing an example of a 4ch LD array).

  Thus, since the LD array 23 is composed of a plurality of LDs and one PD, it is difficult to perform light amount adjustment control (APC operation / APC control) on the plurality of LDs simultaneously. Further, at the time of image creation, a bias current must always be supplied in order to suppress a decrease in the amount of light over time, which is called droop, and even when it is not used, it emits light weakly (offset light emission). For this reason, in the LD array 23, when the initialization or APC operation is performed, offset light emission from other channels (channels) is picked up by the PD element, so that the light amount adjustment control with high accuracy cannot be performed.

  More specifically, as shown in FIG. 5, the APC control is a control in which the light emission amount of the LD array is received by the PD and the resulting current Im is adjusted by the variable resistor Rpd and the analog voltage Vc. That is, the current flowing through the PD is expressed by Im = Vc / Rpd, and the current Im flowing through the PD, that is, the light emission amount of the LD is adjusted by adjusting the analog voltage Vc and the variable resistance Rpd. Since an LD array usually has only one PD, when the LD other than the APC operation emits light, the amount of light is picked up.

  Therefore, the light beam scanning device of the present invention is characterized in that, in a semiconductor laser element having a plurality of light sources, the influence of offset light emission from other channels is corrected when the light amount adjustment control of one channel is performed. As a correction method, before the APC operation, the offset light emission amount of the LD other than the APC operation is measured, and the APC control is corrected according to the light amount. Hereinafter, each example of this correction method will be described. The light beam scanning apparatus of the present invention is premised on the configuration shown in FIG.

  As an example of the correction method, a method of reducing the PD current Im during the APC control according to the offset light emission amount measured before the APC control will be described. FIG. 6 shows the configuration of the light beam scanning apparatus of the present invention for realizing this method. FIG. 6 is a diagram showing a detailed configuration (correction means including an ammeter, a memory, and a CPU) of the LD control unit 22 and the LD array 23 in FIG. 4, and (a) detects offset light. It is a figure which shows time, (b) is a figure which shows the time of performing APC control.

  As shown in FIG. 6A, the PD current amount (Im_offset) due to offset light emission is measured by an ammeter before APC control, and the measurement result is stored in a memory. At this time, the electronic load from the CPU is kept open (the timing sets the time from the synchronization detection signal).

  At the time of APC control, as shown in FIG. 6B, in order to separate the current amount due to the offset emission stored in the memory, a voltage corresponding to Im_offset stored in the memory is calculated in the CPU. The voltage of the electronic load is varied (the figure shows an electronic load using a transistor as an active element). Then, APC control can be performed with the PD current Im_0 corresponding to light emission from the light source of the channel for which APC adjustment is desired. That is, the analog voltage Vc of the LD control unit and the variable resistor Rpd are controlled so that Im_0 = Vc / Rpd.

  As described above, according to the present embodiment, the PD current amount due to the offset light emission measured before the APC control is stored in the memory, and the value of the electronic load is changed according to the magnitude. Thus, the PD current Im_offset for offset light emission can be separated from the PD current. Therefore, since the current corresponding to the weak light emission amount measured in advance is subtracted from the current of the light amount detecting element (PD) at the time of adjusting the light amount, the set values in the control so far (APC target light amount, resistance value at the time of adjusting the light amount This can be realized without changing the analog voltage value.

  As an example of the correction method, a method of changing the resistance value of the variable resistor Rpd for adjusting the light amount according to the offset light emission amount measured before the APC control will be described. FIG. 7 shows the configuration of a light beam scanning apparatus of the present invention for realizing this method. FIG. 7 is a diagram showing a detailed configuration (correction means) of the LD controller 22 and the LD array 23 in FIG. 4, and FIG. 7A is a diagram showing when offset light is detected. b) is a diagram showing the time when the APC control is performed.

  As shown in FIG. 7A, the PD current amount (Im_offset) for offset light emission is stored in the memory before APC control. Then, as shown in FIG. 7B, the resistance value is decreased by Roff in accordance with the Im_offset. At this time, Roff is expressed as Roff = Rpd−Vc / (Im_0 + Im_offset), so that Im_0 + Im_offset flows in the PD, and is calculated in the CPU from the data stored in the memory, and the resistance value is changed.

  As described above, according to the present embodiment, the PD current amount due to the offset light emission measured before the APC control is stored in the memory, and the resistance value is reduced according to the magnitude. Even if extra offset light is picked up by the PD, the target light source can be adjusted to the target light amount. Therefore, since the resistance value of the variable resistor for light amount adjustment is changed according to the weak light emission amount measured in advance, the accuracy of manual light amount adjustment at the time of manufacture can be lowered.

  As an example of the correction method, a method of changing the value of the analog voltage Vc for controlling the light amount according to the offset light emission amount measured before the APC control will be described. The configuration of the light beam scanning apparatus of the present invention for realizing this method is shown in FIG. FIG. 8 is a diagram showing a detailed configuration (correction means including an ammeter, a memory, and a CPU) of the LD control unit 22 and the LD array 23 in FIG. 4, and (a) detects offset light. It is a figure which shows time, (b) is a figure which shows the time of performing APC control.

  As shown in FIG. 8A, the PD current amount (Im_offset) for offset light emission is stored in the memory before APC control. Then, as shown in FIG. 8B, the analog voltage Vc of the LD control unit is increased by Voff according to the Im_offset. At this time, Voff is expressed as Voff = Rpd (Im_0 + Im_offset) −Vc so that Im_0 + Im_offset flows in the PD, and is calculated by the CPU from the data stored in the memory, and the analog voltage value is changed.

  As described above, according to the present embodiment, the PD current amount due to the offset emission measured before the APC control is measured by the ammeter, and the analog voltage change corresponding to the current amount is determined by the CPU. Then, by changing the analog voltage of the LD control unit, the target light source can be adjusted to the target light amount even if extra offset light emission is picked up by the PD. Therefore, in order to change the value of the analog voltage for controlling the amount of light according to the weak light emission amount measured in advance, unlike the method of changing the resistance value in the second embodiment, it is possible to change by changing the analog voltage setting value for control. Is possible.

  In the first to third embodiments, a method for measuring and correcting offset light emission of a light source other than the APC operation in advance has been described. However, in this embodiment, the offset light emission amount is set to a fixed value (preliminarily set) in addition to these methods. A method of performing control so as to achieve the target light amount and correcting the amount corresponding to the fixed light emission amount will be described. This method can be performed by the same correction method as in the first to third embodiments. That is, a method of reducing the PD current by a fixed offset light emission amount (corresponding to the first embodiment), a method of reducing the variable resistor for adjusting the light amount (corresponding to the second embodiment), and a method of increasing the analog voltage for controlling the light amount. (Corresponding to Example 3) can be realized. These methods require means for setting the offset light emission amount as a fixed value, but unlike Examples 1 to 3, means for calculating a correction value according to the light quantity measurement result (FIGS. 6 to 8). The ammeter, memory, and CPU shown in FIG. In the following description, the means for setting the offset light emission amount as a fixed value is an LD control unit as an example.

  FIG. 9 shows the configuration of the light beam scanning apparatus of the present invention for realizing the method of this embodiment. FIG. 9 is a diagram showing a detailed configuration of the LD control unit 22 and the LD array 23 in FIG. 4 (correction means is an LD control unit), and (a) and (b) are APCs of offset light. It is a figure which shows the time of performing control.

  In the method of this embodiment, in order to set the offset light emission amount to a fixed value, the APC control of the offset light emission amount other than the light source performing the APC control is performed immediately before the APC control of the desired light source. This can be realized by changing the analog voltage Vc or the variable resistor Rpd during the APC control of the offset light emission amount. That is, as shown in FIG. 9A, Vc is changed to Vc1 = (Im_offset) × (Rpd) when the current Im_offset flowing in the PD during offset light emission is set to a fixed value. Alternatively, as shown in FIG. 9B, Rpd is changed to Rpd1 = Vc / (Im_offset). By performing this control immediately before the APC control of each light source, a constant Im_offset can be obtained.

  As described above, according to the present embodiment, in order to control the weak light emission amount of the light source other than the light source performing the light amount adjustment control so as to become the predetermined target light amount (fixed value), The effect of the first to third embodiments can be obtained without requiring a means for calculating the correction amount from the offset light emission amount as in FIG.

The methods of the first to fourth embodiments need to be performed for each light source when performing initialization and line APC. The flow is as shown in FIG.
First, offset light is corrected (step S11), and the target channel is initialized (step S2). If initialization of all channels has not been completed (step S13 / NO), the process returns to step S11. When initialization of all the channels is completed (step S13 / YES), one line scanning of all the channels is performed (step S14). Then, the offset light is corrected (step S15), and the APC control of the target channel is performed (step S16). If the APC control for all channels has not been completed (step S17 / NO), the process returns to step S15. If the APC control for all channels is completed (step S17 / YES), and the scanning is completed (step S18 / YES), a series of processing is terminated, and if the scanning is not completed (step S18 / NO) ), And returns to step S14.

  In the “offset light correction” in the flow of FIG. 10, in the first to third embodiments, offset light other than the APC target light source is measured in advance, and the correction amount corresponding to the offset light is calculated and corrected. . Further, in the case of the fourth embodiment, control with offset light as a fixed value is performed, and correction corresponding to the offset light amount is performed.

  Next, a method of reducing the amount of offset light emission to a level that does not affect the APC control by reducing the amount of current flowing to a light source other than the light source performing the APC control will be described separately from the methods of the first to fourth embodiments. . In this method, it is possible to classify by the control method of the current flowing through each light source. First, there is a method of reducing the total sum of currents flowing through the light sources other than the APC control and reducing the total offset light amount to an extent that does not affect the APC control. In this method, since the offset light emission amount is controlled by the sum of the current amounts of the respective light sources, the control system can be realized by one system. As another method, there is a method of individually controlling the current amount of each light source that emits offset light. This can individually control the amount of each light source that emits offset light according to the physical distance to the light source performing APC control, thereby minimizing the influence of the LD characteristics due to thermal fluctuations. An example is shown in FIG. Since the light source d having a long physical distance to the light source a performing APC control has less thermal influence than the light sources b and c, the amount of current supplied to the light source can be reduced. For example, when four LDs are arranged at positions that form the vertices of a square, the distance between the light source a and the light source d is about 1.4 times the distance between the light source a and the light source b or between the light source a and the light source c ( Therefore, the thermal effects of the light sources a and d are greater than the thermal effects of the respective light sources between the light sources a and b or c. Here, the relationship is inversely proportional to about 1.4 times.

  As described above, according to the present invention, since the device for correcting weak light emission other than the light source for adjusting the light amount is provided, the light amount can be adjusted with high accuracy.

  In addition, according to the present invention, the weak light emission amount other than the light source performing the light amount adjustment control is measured and corrected before the light amount adjustment control. Enables accurate correction according to

  In addition, according to the present invention, since the current corresponding to the weak light emission amount measured in advance is subtracted from the current of the light amount detection element at the time of adjusting the light amount, the set values in the past control (APC target light amount, when adjusting the light amount) The first embodiment can be realized without changing the resistance value or the analog voltage value of the first embodiment.

  Further, according to the present invention, since the resistance value of the variable resistor for light amount adjustment is changed according to the weak light emission amount measured in advance, the accuracy of manual light amount adjustment at the time of manufacture can be lowered (Example) 2).

  In addition, according to the present invention, the analog voltage for control is different from the method of changing the resistance value of the second embodiment in order to change the value of the analog voltage for controlling the light amount according to the weak light emission amount measured in advance. This can be dealt with by changing the set value (Example 3).

  In addition, according to the present invention, in order to control the weak light emission amount of the light source other than the light source that is performing the light amount adjustment control so as to become a certain target light amount, the correction amount is calculated from the offset light emission amount as in the first to third embodiments. No calculation means is required (Example 4).

  Further, according to the present invention, no means for calculating a correction value is required in order to reduce the current flowing to the light source other than the light source that is performing the light amount adjustment control during the light amount adjustment control (Example 5).

  Further, according to the present invention, in order to reduce the total sum of the currents flowing through the light sources other than the light source that is performing the light amount adjustment control, the control system for the weak light emission amount may be one system (Example 5).

  In addition, according to the present invention, the amount of weak light emission can be adjusted depending on the magnitude of the thermal influence due to the physical position because the current flowing to the light source other than the light source for which the light amount adjustment control is performed is individually controlled. (Example 5).

  As mentioned above, although each Example of this invention was described, it is not limited to said each Example, A various deformation | transformation is possible in the range which does not deviate from the summary.

  For example, the control operation in the above-described embodiment can be executed by hardware, software, or a combined configuration of both.

  In addition, when executing processing by software, a program in which a processing sequence is recorded is installed in a memory in a computer incorporated in dedicated hardware and executed, or a general-purpose capable of executing various processing It is possible to install and execute a program on a computer.

  For example, the program can be recorded in advance on a hard disk or a ROM (Read Only Memory) as a recording medium.

  Alternatively, the program is temporarily or permanently stored on a removable recording medium such as a CD-ROM (Compact Disc Read Only Memory), an MO (Magneto optical) disc, a DVD (Digital Versatile Disc), a magnetic disc, or a semiconductor memory. It can be stored (recorded).

  Such a removable recording medium can be provided as so-called package software.

  The program is installed on the computer from the removable recording medium as described above, or is wirelessly transferred from the download site to the computer, or is wired to the computer via a network such as a LAN (Local Area Network) or the Internet. On the other hand, the computer can receive the transferred program and install it on a recording medium such as a built-in hard disk.

  In addition to being executed in time series in accordance with the processing operations described in the above embodiments, the processing capability of the apparatus that executes the processing, or to be executed in parallel or individually as required Is also possible.

  The present invention can be applied to an apparatus / apparatus, system, method, program, etc. that simultaneously drives a plurality of semiconductor lasers and simultaneously performs optical writing on a plurality of lines.

1 is a diagram illustrating a configuration of an image forming apparatus of the present invention. It is a figure which shows the structure which looked at the light beam scanning apparatus of this invention from the top. It is a flowchart which shows the fundamental operation | movement of the light beam scanning apparatus of this invention. It is a figure which shows the basic composition of the light beam scanning apparatus of this invention. It is a figure which expands and shows the part of the LD control part and LD array in the light beam scanning apparatus of this invention. FIG. 5 is a diagram illustrating a detailed configuration of the LD control unit 22 and the LD array 23 in FIG. 4 according to the first embodiment of the light beam scanning apparatus of the present invention, and FIG. FIG. 4B is a diagram illustrating the time when APC control is performed. FIG. 6 is a diagram illustrating a detailed configuration of the LD control unit 22 and the LD array 23 in FIG. 4 according to the second embodiment of the light beam scanning apparatus of the present invention, and FIG. FIG. 4B is a diagram illustrating the time when APC control is performed. FIG. 5 is a diagram illustrating a detailed configuration of the LD control unit 22 and the LD array 23 in FIG. 4 according to the third embodiment of the light beam scanning apparatus of the present invention, and FIG. FIG. 4B is a diagram illustrating the time when APC control is performed. FIG. 5 is a diagram illustrating a detailed configuration of the LD control unit 22 and the LD array 23 in FIG. 4 according to a fourth embodiment of the light beam scanning apparatus of the present invention, and FIGS. It is a figure which shows each example when performing. It is a flowchart which shows the characteristic operation | movement of the light beam scanning apparatus of this invention. It is a figure which shows the example of arrangement | positioning of a several light source concerning Example 5 of the light beam scanning apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transfer paper 2 Conveyance belt 3 Conveyance roller (drive roller)
4 Conveying roller (driven roller)
5 Feed tray 6 Photosensitive drum 7 Charger 8 Exposure unit (light beam scanning device)
9 Developing Device 10 Photoconductor Cleaner 11 Laser Light (Light Beam)
DESCRIPTION OF SYMBOLS 12 Transfer device 13 Fixing device 14 Registration sensor 20 Scanner part 21 Write control part 22 LD control part (an example of a light source control means)
23 LD array (an example of light beam generating means)
24 control unit 31 LD unit BK
32 LD unit Y
33 Cylinder lens BK
34 Cylinder lens Y
35 reflective mirror BK
36 Reflective mirror Y
37 Polygon mirror 38 fθ lens BKC
39 fθ lens YM
40 1st mirror BK
41 First mirror Y
42 LD Unit C
43 LD Unit M
44 Cylinder lens C
45 Cylinder lens M
46 First Mirror C
47 First Mirror M
48 Cylinder mirror BKC
49 Cylinder mirror YM
50 sensor BKC
51 Sensor YM
52 LD control plate C
53 LD control board BK
54 LD control plate Y
55 LD control plate M

Claims (3)

In a light beam scanning apparatus comprising: a light beam generating means having a plurality of light emitting elements and one light receiving element; and a light source control means for controlling lighting of the plurality of light emitting elements.
When the light source control unit performs light amount adjustment control on one of the plurality of light emitting elements of the light beam generating unit, weak light emission from light emitting elements other than the one light emitting element is performed. A correction means for correcting the influence,
The correction unit measures a weak light emission amount of a light emitting element other than the light emitting element on which the light amount adjustment control is performed before the light source control unit performs the light amount adjustment control, and according to the measured weak light emission amount. The light amount adjustment control is corrected, and a current corresponding to the pre-measured weak light emission amount is subtracted from the current of the light receiving element when the light amount adjustment control is performed, and other than the light emitting element for which the light amount adjustment control is performed. A light beam scanning apparatus characterized by controlling a weak light emission amount of a light emitting element to a preset target light amount and correcting light amount adjustment control according to the target light amount.   2. The light beam scanning apparatus according to claim 1, wherein the correction unit subtracts a current corresponding to the preset target light amount from a current of the light receiving element when the light amount adjustment control is performed. An image forming apparatus comprising the light beam scanning device according to claim 1 .

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