JP2009128484A - Optical scanner and image forming apparatus including the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical scanner preventing out-of-sync of an output signal of a light receiving element due to an uneven light quantity of a plurality of semiconductor lasers, and to provide an image forming apparatus including the same. <P>SOLUTION: The optical scanner includes: a light receiving means 11 for detecting beams emitted from a plurality of semiconductor lasers 2a, 2b; delaying means 47, 49 for generating delay time corresponding to the light quantity of the plurality of the semiconductor lasers; and a means for generating a reference signal based on the delay means. When fall and rise edges of beam detection signals 45, 46 output from the light receiving means by radiation of a prescribed semiconductor laser are input, the reference signal is generated from the means for generating the reference signal at the delay time corresponding to the light quantity of the semiconductor laser from the delay means. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical scanning device and an image forming apparatus including the same.

An optical scanning device provided in an electrophotographic image forming apparatus drives a semiconductor laser in accordance with input image data, and forms an electrostatic latent image in accordance with the image data on a photoreceptor. In such an optical scanning device, a horizontal synchronization (BD) signal (output signal) that serves as a writing reference for the electrostatic latent image in the main scanning direction of the photosensitive member is detected by a beam detection circuit. In such an apparatus, for example, in Patent Document 1, even if the light beam intensity changes, this effect is prevented to a minimum, and the generation timing of the synchronization signal is stabilized so that the image writing timing in the main scanning direction does not change. A method has been proposed.
Japanese Patent No. 3270565

  However, in Patent Document 1, when a plurality of light beam detections are performed in one scan, the response speed is insufficient. Further, when the light amounts of a plurality of light beams are remarkably different, there is a problem that a threshold for generating a beam detection signal cannot be generated with high accuracy.

  The present invention has been made to solve the above-described problems, and an optical scanning device capable of preventing a timing shift of an output signal of a light receiving element due to a variation in light amounts of a plurality of semiconductor lasers, and an image formation including the same An object is to provide an apparatus.

  The present invention has the following configuration in order to solve the above-described problems.

  Laser driving means for outputting a driving current so that a plurality of semiconductor lasers have a predetermined light amount, and scanning on the image carrier with beams emitted from the plurality of semiconductor lasers to form a latent image on the image carrier. An optical scanning device for detecting a beam emitted from the plurality of semiconductor lasers, a delay unit for generating a delay time corresponding to a light amount of the plurality of semiconductor lasers, and a delay unit based on the delay unit A means for generating a reference signal, and the delay when a falling edge or a rising edge of a beam detection signal output from the light receiving means by irradiation of a predetermined semiconductor laser among the plurality of semiconductor lasers is input. An optical scanning device characterized in that the reference signal is generated from the means for generating the reference signal with a delay time corresponding to the light quantity of the semiconductor laser from the means.

  It is possible to provide an optical scanning device and an image forming apparatus including the optical scanning device capable of preventing a timing shift of an output signal of a light receiving element due to a variation in light amount of a plurality of semiconductor lasers.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to examples.

  FIG. 1 is an extracted configuration diagram of an image forming apparatus including an optical scanning device according to the present embodiment. Reference numeral 1 denotes a laser unit, which is configured so that a plurality of beams can be emitted simultaneously by the semiconductor lasers 2a and 2b, which are light sources, and the semiconductor lasers 2a and 2b have a predetermined amount of light by a laser driving circuit 13 similarly provided in the laser unit 1. Outputs drive current.

  A combining unit 3 is a trapezoidal prism having a polarizing beam splitter (dotted line frame) inside and a polarizing filter attached to the beam output surface. The polarization beam splitter has a characteristic of traveling straight or reflecting the beam depending on the phase of the polarized wave.

  The laser beam L1b emitted from the semiconductor laser 2b is deflected by the hatched portion of the synthesis unit 3, further deflected by the polarization beam splitter, passes through the polarization filter, and exits from the synthesis unit 3. On the other hand, the laser beam L1a emitted from the semiconductor laser 2a is emitted from the laser unit 1 so that the polarization direction differs from that of the laser beam L1b by 90 °, and is emitted from the synthesis unit 3 so as to go straight through the polarization beam splitter and the polarization filter. Thus, the laser beam L1a and the laser beam L1b are arranged at a predetermined interval in the main / sub scanning direction.

  In the non-image region, the laser beam L1a emitted from the semiconductor laser 2a and the laser beam L1b emitted from the semiconductor laser 2b reach the rotating polygon mirror 6 through the collimating lens 4 and the cylindrical lens 5. The rotary polygon mirror 6 is rotated at a constant angular velocity by a rotary polygon mirror drive circuit 7 including a scanner motor. The laser beam that has reached the rotary polygon mirror 6 is deflected by the rotary polygon mirror 6, converted by the f-θ lens 8 so as to scan at a constant speed in the direction perpendicular to the rotation direction of the photosensitive drum 10, and beam detection (hereinafter referred to as “BD”). The sensor 11 receives light.

  In the image area, the laser beam L2a and the laser beam L2b are emitted from the f-θ lens 8, and then irradiate the photosensitive drum 10 (on the image carrier) via the reflection mirror 9, thereby forming a latent image. Do. The latent image formed on the photosensitive drum 10 is transferred to and fixed on a sheet after toner development to print an image.

  FIG. 2 is a schematic diagram for explaining the positional relationship between the BD sensor 11 and the beam spot on the BD sensor 11. The following specifications will be described as an example.

  The main scanning speed is the speed at which the rotary polygon mirror 6 scans in the main scanning direction, and the BD sensor diameter is the sensor shape (circular) of the BD sensor 11.

  The spot diameter is the size of the spot on the BD sensor 11 irradiated from the semiconductor lasers 2a and 2b. The spot diameters of the laser beams L1a and L1b irradiated to the BD sensor 11 are different from the spot diameter irradiated to the photosensitive drum 10 because a lens (not shown) is arranged on the upper surface of the BD sensor 11. The spot interval is an interval in the main scanning direction on the upper surface of the BD sensor 11.

Specifications Main scanning resolution: 600 [dpi]
Main scanning speed: 2,500,000 [mm / sec]
Image clock: 60 [MHz]
BD sensor diameter: Φ1.0 [mm]
Spot diameter (on BD sensor)
Main: 0.5 [mm]
Secondary: 0.2 [mm]
Spot interval: 1.175 [mm]
From the above specifications, the time difference until the semiconductor laser 2a and the semiconductor laser 2b on the BD sensor 11 reach the BD sensor 11, that is, the BD phase difference is obtained as follows.

BD phase difference = (spot interval) ÷ (main scanning speed)
= 1.175 ÷ 2,500,000
= 470 [ns]
FIG. 3 is a block diagram showing the configuration of the BD sensor 11.

  The BD sensor 11 includes an electric circuit for outputting a photo sensor 24 and a beam detection (BD) signal 33. 21 is a power supply terminal, 22 is a ground (GND) terminal, and 23 is a beam detection (BD) output terminal. The power supply terminal 21 is connected to the power supply (Vcc) and the ground (GND) terminal 22 is connected to the GND. Reference numeral 24 denotes a photosensor, which is made of, for example, silicon. The cathode of the photosensor 24 is connected to the power supply via the power supply terminal 21 to apply a reverse bias, and the anode is connected to GND via the voltage conversion resistor 25 and the ground (GND) terminal 22.

  When the photosensor 24 is irradiated with light having a predetermined wavelength, a current is output to the voltage conversion resistor 25. The voltage conversion resistor 25 converts the current output from the photosensor 24 into a voltage and generates a photosensor output signal 26.

  The photosensor output signal 26 is input to a gain amplifier a 27 and a gain amplifier b 29. The photosensor output signal 26 is amplified to a gain of 8 times by the gain amplifier a27 and to a gain of 2 times by the gain amplifier b29. The gain amplifier b29 sets a threshold value, and holds the gain amplifier b output signal 30 with the hold capacitor 31.

  A comparator (comparator) 32 obtains a beam detection (BD) signal 33 by comparing the gain amplifier a output signal 28 and the gain amplifier b output signal 30.

  FIG. 4 is a characteristic graph showing the amount of incident light and the BD phase error characteristic of the BD sensor 11.

  Even when the semiconductor laser 2a and the semiconductor laser 2b are adjusted to a preset light amount at a predetermined image height on the photosensitive drum 10, the amount of light that the semiconductor laser 2a and the semiconductor laser 2b irradiate the BD sensor 11 has due to the characteristics of the optical components. A difference occurs.

  The sensitivity of the photosensor 24 of the BD sensor 11 varies depending on the amount of change in the amount of light received, and the output current varies. As a result, the time from the start of incidence of the photosensor 24 to the output of the beam detection (BD) signal 33 varies. When the amount of light incident on the BD sensor 11 differs between the semiconductor laser 2a and the semiconductor laser 2b, the BD phase difference fluctuates, resulting in a BD phase error. For example, when the light quantity of the semiconductor laser 2a incident on the BD sensor 11 is 191 [μW], the BD phase error is ±± with respect to the BD phase difference (= 470 [ns]) when the light quantity of the semiconductor laser 2b varies by 10 [%] 2.0 [ns]. When the horizontal resolution is 600 dpi, it corresponds to ± 1/8 pixel on the photosensitive drum 10.

[Correction Method for Beam Detection (BD) Signal 33]
FIG. 5 shows a time chart for explaining a light amount difference between the beam detection (BD) sensor and the photosensitive drum. As shown in FIG. 1, in an optical system in which the area of each surface of the rotary polygon mirror 6 is reduced and a laser beam is irradiated on the entire surface of the rotary polygon mirror 6, the amount of light in the image area on the photosensitive drum 10 varies. appear. In order to minimize this, the light amounts of the semiconductor lasers 2 a and 2 b are adjusted so as to be a predetermined light amount at an arbitrary position on the photosensitive drum 10. In this case, the amount of light that the semiconductor lasers 2a and 2b irradiate on the BD sensor 11 varies (ΔPbd).

  6 to 9 are time charts for explaining a method of correcting the beam detection (BD) signal 33 according to the present invention. An example in which the semiconductor laser 2a and the semiconductor laser 2b are received by one BD sensor 11 and a beam detection (BD) signal 33 is output will be described. The beam arrangement in the main scanning direction is such that the semiconductor laser 2a is at the head of the semiconductor laser 2b as described in FIG.

  A method for correcting the BD phase error of the beam detection (BD) signal 33 due to the difference in the light quantity conditions of the semiconductor laser 2a and the semiconductor laser 2b incident on the BD sensor 11 will be described below.

  The incident light waveform of the BD sensor 11 is laser emission profile data for irradiating the BD sensor 11 obtained as a result of driving the semiconductor laser 2a and the semiconductor laser 2b in accordance with each control mode.

  The beam detection (BD) signal 33 is output from the BD sensor 11 as a result of irradiating the BD sensor 11 with an optical profile represented by the BD sensor 11 incident light waveform.

  The laser 2a horizontal synchronizing signal (HDa) 48 and the laser 2b horizontal synchronizing signal (HDb) 50 are beam detection (BD) signal 33 correction signals, which are output delay time fluctuations due to fluctuations in the amount of incident light of the BD sensor 11 shown in FIG. It is obtained as a result of correcting the generated BD phase error.

  The reference correction value is set from the falling edge of the beam detection (BD) signal 33 when the light amounts of the lasers 2a and 2b are equal to the BD reference light amount (FIG. 6), and the laser 2a horizontal synchronization signal (HDa) 48 and the laser. The time until the falling edge of the 2b horizontal synchronizing signal (HDb) 50 is set. The output timings of the laser 2a horizontal synchronizing signal (HDa) 48 and the laser 2b horizontal synchronizing signal (HDb) 50 are obtained by referring to FIG. 4 with respect to the phase error obtained from the assumed light quantity fluctuation amount of the semiconductor laser 2a and the semiconductor laser 2b. If it is set to the maximum value, it can be corrected based on the reference correction value. A specific example will be described below.

(1) When the light amounts of the lasers 2a and 2b are not equal to the BD reference light amount (FIG. 7)
(A) When the light amounts of the lasers 2a and 2b are larger than the BD reference light amount When both the light amounts of the semiconductor laser 2a and the semiconductor laser 2b are larger than the BD reference light amount, the falling edge of the beam detection (BD) signal 33 is Both the laser 2a and the semiconductor laser 2b are output prior to the reference correction value. Therefore, the values obtained by adding the phase difference from the beam detection (BD) signal 33 at the time of the BD reference light amount to the reference correction value are the laser 2a and laser 2b phase setting values.

(B) When the light amounts of the laser 2a and laser 2b are smaller than the BD reference light amount When both the light amounts of the semiconductor laser 2a and the semiconductor laser 2b are smaller than the BD reference light amount, the falling edge of the beam detection (BD) signal 33 is Both the laser 2a and the semiconductor laser 2b are output later with respect to the reference correction value. Therefore, the values obtained by subtracting the phase difference from the beam detection (BD) signal 33 at the time of the BD reference light amount from the reference correction value are the laser 2a and laser 2b phase setting values.

(2) When only the light amount of the laser 2a is not equal to the BD reference light amount (FIG. 8)
(A) When the light quantity of the laser 2a is larger than the BD reference light quantity When the semiconductor laser 2a is larger than the BD reference light quantity, the falling edge of the beam detection (BD) signal 33 is only for the semiconductor laser 2a with respect to the reference correction value. Output in advance. Therefore, the value obtained by adding the phase difference from the beam detection (BD) signal 33 at the time of the BD reference light amount to the reference correction value is the laser 2a phase setting value. On the other hand, the semiconductor laser 2b has a BD reference light amount, and the laser b phase setting value becomes a reference correction value.

(B) When the light quantity of the laser 2a is smaller than the BD reference light quantity When the semiconductor laser 2a is smaller than the BD reference light quantity, the falling edge of the beam detection (BD) signal 33 is only for the semiconductor laser 2a with respect to the reference correction value. It will be output later. Accordingly, a value obtained by subtracting the phase difference from the beam detection (BD) signal 33 at the time of the BD reference light amount from the reference correction value becomes the laser 2a phase setting value. On the other hand, the semiconductor laser 2b has a BD reference light amount, and the laser b phase setting value becomes a reference correction value.

(3) When only the light amount of the laser 2b is not equal to the BD reference light amount (FIG. 9)
(A) When the light amount of the laser 2b is larger than the BD reference light amount When the semiconductor laser 2b is larger than the BD reference light amount, the falling edge of the beam detection (BD) signal 33 is only for the semiconductor laser 2b with respect to the reference correction value. Output in advance. Therefore, the value obtained by adding the phase difference from the beam detection (BD) signal 33 at the time of the BD reference light amount to the reference correction value is the laser 2b phase setting value. On the other hand, the semiconductor laser 2a has a BD reference light amount, and the laser a phase setting value becomes a reference correction value.

(B) When the light amount of the laser 2b is smaller than the BD reference light amount When the semiconductor laser 2b is smaller than the BD reference light amount, the falling edge of the beam detection (BD) signal 33 is only for the semiconductor laser 2b with respect to the reference correction value. It will be output later. Accordingly, a value obtained by subtracting the phase difference from the beam detection (BD) signal 33 at the time of the BD reference light amount from the reference correction value is the laser 2b phase setting value. On the other hand, the semiconductor laser 2a has a BD reference light amount, and the laser a phase setting value becomes a reference correction value.

[Beam Detection (BD) Signal 33 / Phase Correction Adjustment Method]
FIG. 10 shows a schematic configuration diagram of a laser 2a / phase time and laser 2b / phase time measuring apparatus. 1 to 11 except the photosensitive drum 10 in FIG. 1 are optical scanning devices of the present invention. Reference numeral 12 denotes an avalanche photodiode, which is a test tool sensor, and is disposed at a position where the semiconductor laser 2 a and the semiconductor laser 2 b irradiate a predetermined image height of the photosensitive drum 10.

  FIG. 11 is a time chart showing the relationship between the beam detection (BD) signal 33 and the output signal of the test tool sensor 12. The laser 2a / phase time τna is the time interval between the beam detection (BD) signal 33 and the test tool sensor 12 output signal when the BD sensor 11 is irradiated with the semiconductor laser 2a with a certain amount of light. The laser 2b / phase time τnb is the time interval between the beam detection (BD) signal 33 and the sample sensor 12 output signal when the BD sensor 11 is irradiated with the semiconductor laser 2b with a certain amount of light. As described with reference to FIG. 5, the laser 2a / phase time τna and the laser 2b / phase time τnb vary depending on the difference in the amount of light emitted from the semiconductor laser 2a or the semiconductor laser 2b.

  FIG. 12 is an adjustment flowchart of the beam detection (BD) signal 33 / phase correction.

(1) Reference correction value / measuring method Each phase time when the irradiation light amounts of the semiconductor laser 2a and the semiconductor laser 2b are both BD reference light amounts is measured to obtain a correction reference value.

  First, the semiconductor laser 2a is turned on (S101), the light amount (BD light amount) Poa on the BD sensor 11 is adjusted to be a reference light amount (S102), and the semiconductor laser 2a is turned off (S103). Next, the semiconductor laser 2b is turned on (S104), the light amount (BD light amount) Pob on the BD sensor 11 is adjusted to become the reference light amount (S105), and the semiconductor laser 2b is turned off (S106).

  The semiconductor laser 2a is turned on again (S107), scanned by being deflected by the rotary polygonal mirror 6 (S108), the time interval between the beam detection (BD) signal 33 and the test tool sensor 12 output signal is measured, and the laser 2a / The correction reference value τ0a is used. After the measurement of the laser 2a / correction reference value τ0a is completed (S109), the scanning is terminated and the semiconductor laser 2a is turned off (S110). Similarly, the semiconductor laser 2b is turned on (S111), scanned by being deflected by the rotary polygon mirror 6 (S113), the time interval between the beam detection (BD) signal 33 and the test tool sensor 12 output signal is measured, and the laser 2b / The correction reference value τ0b is set (S114). After the measurement of the laser 2b / correction reference value τ0b is completed, the scanning is terminated and the semiconductor laser 2b is turned off (S115). Finally, a reference phase difference (τ0a−τ0b) is calculated (S116).

(2) Phase setting value / calculation method Each phase time when the irradiation light quantity of the semiconductor laser 2a and the semiconductor laser 2b is the reference light quantity of the photosensitive drum 10 is measured to obtain the phase setting value.

  First, the semiconductor laser 2a is turned on (S201), the light amount on the photosensitive drum 10 (drum surface light amount) P1a is adjusted to be the reference light amount (S202), and the semiconductor laser 2a is turned off (S203). Next, the semiconductor laser 2b is turned on (S204), the light amount on the photosensitive drum 10 (drum surface light amount) P1b is adjusted to become the reference light amount (S205), and the semiconductor laser 2b is turned off (S206).

  The semiconductor laser 2a is turned on again (S207), scanned by being deflected by the rotary polygon mirror 6 (S208), the time interval between the beam detection (BD) signal 33 and the tester sensor 12 output signal is measured, and the laser 2a / The phase error τ1a is set (S209). After the measurement of the laser 2a / phase error τ1a is finished, the scanning is finished and the semiconductor laser 2a is turned off (S210). Similarly, the semiconductor laser 2b is turned on (S211), scanned by being deflected by the rotary polygon mirror 6 (S212), the time interval between the beam detection (BD) signal 33 and the tester sensor 12 output signal is measured, and the laser 2b / Phase error τ1b (S213). After the measurement of the laser 2b / phase error τ1b is completed, the scanning is terminated and the semiconductor laser 2b is turned off (S214).

  The laser 2a / phase error τ1a obtained from the above and the reference correction value are calculated to calculate the laser 2a phase setting value (S215), and the laser 2b / phase error τ1b and the reference correction value (S216) are calculated to calculate the laser 2b phase setting value. Ask.

[Correction]
FIG. 13 is a block diagram of a beam detection (BD) control unit for explaining the correction operation, FIG. 14 is a time chart for explaining the operation, and FIG. 15 is an operation flowchart.

  A beam detection (BD) control unit 41 inputs a beam detection (BD) signal 33 output from the BD sensor 11 to a BD separation circuit 44 via a waveform shaping circuit 42 including a low-pass filter (LPF). Is done. The BD separation circuit 44 is a laser 2a beam detection (BD) signal 45 obtained by emitting light from the semiconductor laser 2a from the beam detection (BD) signal 33 and a laser 2b beam detection (BD) signal 46 obtained by emitting light from the semiconductor laser 2b. Is output separately.

  A laser emission control circuit 55 generates a laser emission control signal 56 from the laser 2a beam detection (BD) signal 45 output from the BD separation circuit 44. The laser drive circuit 13 provided in the laser unit 1 causes the semiconductor laser 2 a and the semiconductor laser 2 b to emit light based on the laser emission control signal 56. The laser unit 1 has a laser drive circuit 13 and an EEPROM 14 that is a storage unit as an integral configuration.

  The laser 14a phase setting value and laser 2b phase setting value shown in FIGS. 7 to 9 are stored in the EEPROM 14, and are taken into the CPU 52 at a predetermined timing and input to the laser 2a phase delay circuit 47 and the laser 2b phase delay circuit 49. To do. When the laser 2a phase delay circuit 47 detects the falling edge of the laser 2a light beam detection signal 45 from the BD separation circuit 44, the laser 2a phase delay circuit 47 delays the time corresponding to the laser 2a phase set value, and the laser 2a horizontal synchronization signal (HDa) 48 ( (Reference signal) is output. Similarly, when the laser 2b phase delay circuit 49 detects the falling edge of the laser 2b light beam detection signal 46 from the BD separation circuit 44, the laser 2b phase delay circuit 49 delays the time corresponding to the laser 2b phase setting value, and the laser 2b horizontal synchronization signal (HDb) 50 (reference signal) is output.

  The optical scanning device according to the present embodiment has a function capable of preventing the timing deviation of the output signals of the light receiving elements even when the light amounts of the beams of the plurality of semiconductor lasers vary as described above.

Configuration diagram of optical scanning device in embodiment Schematic explaining the positional relationship between a BD sensor and a beam spot Block diagram showing the configuration of the BD sensor Characteristic graph showing incident light quantity and BD phase error characteristics of BD sensor Time chart for explaining a light amount difference between the beam detection sensor and the photosensitive drum in the embodiment Time chart for explaining a correction method when the light quantity of the laser 2a and the laser 2b is equal to the BD reference light quantity Time chart for explaining a correction method when the light amounts of the lasers 2a and 2b are not equal to the BD reference light amount Time chart for explaining a correction method when only the light amount of the laser 2a is not equal to the BD reference light amount Time chart for explaining a correction method when only the light amount of the laser 2b is not equal to the BD reference light amount Schematic configuration diagram of laser 2a / phase time and laser 2b / phase time measuring device Time chart showing the relationship between the beam detection signal and the output signal of the tool sensor Adjustment flowchart of beam detection signal / phase correction Block diagram of beam detection controller Time chart explaining the operation of the beam detection controller Operation flowchart of beam detection control unit

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Laser unit 2a, 2b Semiconductor laser 3 Synthesis | combination unit 4 Collimator lens 5 Cylindrical lens 6 Rotating polygon mirror 7 Rotating polygon mirror drive circuit 8 f-theta lens 9 Reflecting mirror 10 Photosensitive drum 11 Beam detection sensor (corresponding to light receiving means)
12 Test tool sensor 13 Laser drive circuit (corresponding to laser drive means)
14 EEPROM (corresponding to storage means)
21 Power supply terminal 22 Ground terminal 23 Beam detection output terminal 24 Photo sensor 25 Voltage conversion resistor 26 Photo sensor output signal 27 Gain amplifier a
28 Gain amplifier a output signal 29 Gain amplifier b
30 Gain amplifier b output signal 31 Hold capacitor 32 Comparator
33 Beam detection signal 41 Beam detection control unit 42 Waveform shaping circuit 43 Waveform shaping circuit output signal 44 Beam detection signal separation circuit 45 Laser 2a beam detection signal 46 Laser 2b beam detection signal 47 A Laser phase delay circuit (corresponding to drive means)
48 Horizontal sync signal a
49 B laser phase delay circuit (corresponding to drive means)
50 Horizontal sync signal b
51 Phase setting value 52 CPU
53 Laser 2a phase delay data 54 Laser 2b phase delay data 55 Laser light emission control circuit 56 Laser light emission control signal 57 Laser 2a drive signal 58 Laser 2b drive signal

Claims (5)

Laser driving means for outputting a driving current so that a plurality of semiconductor lasers have a predetermined light amount, and scanning on the image carrier with beams emitted from the plurality of semiconductor lasers to form a latent image on the image carrier. An optical scanning device,
A light receiving means for detecting beams emitted from the plurality of semiconductor lasers;
Delay means for generating a delay time corresponding to the light quantity of the plurality of semiconductor lasers;
Means for generating a reference signal based on the delay means;
Among the plurality of semiconductor lasers, when a falling edge or a rising edge of a beam detection signal output from the light receiving unit is input by irradiation of a predetermined semiconductor laser, the delay unit corresponds to the light amount of the semiconductor laser. An optical scanning device characterized in that a reference signal is generated from means for generating the reference signal according to a delay time. Storage means for storing a delay time generated by the delay means;
2. The optical scanning device according to claim 1, wherein the laser driving unit and the storage unit are integrated.   When the light quantity of the plurality of semiconductor lasers is a predetermined light quantity, each semiconductor laser with respect to the plurality of semiconductor lasers with reference to the delay time generated by the delay means of the beam detection signal output from the light receiving means 2. The optical scanning device according to claim 1, wherein a delay time of the delay means is generated by calculating a change amount of the light quantity. Storage means for storing a delay time of the delay means;
The laser driving means and the storage means are integrated, and when the light quantity of the plurality of semiconductor lasers is a predetermined light quantity, the delay time of the delay means of the beam detection signal output from the light receiving means is used as a reference. 4. The optical scanning device according to claim 3, wherein a result of generating a delay time of the delay means by calculating a light amount change amount of each semiconductor laser for a plurality of semiconductor lasers is stored in the storage means.   An image forming apparatus comprising the optical scanning device according to claim 1.

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