JP2000255099A - Imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imaging apparatus in which unnecessary radiation radio wave can be suppressed through a simple arrangement. SOLUTION: An image data output section 34 comprises JK flip-flop circuits 60, 62 and AND circuits 64, 66. The JK flip-flop circuit 60, 62 has a J terminal connected with a constant voltage power supply and a grounded inverted K terminal. A video clock is inputted to a CK terminal. The JK flip-flop circuit 62 has a Q terminal connected with one input terminal of the AND circuit 64 and an inverted Q terminal connected with one input terminal of the AND circuit 66. An image data signal is inputted to the other input terminal of the AND circuits 64, 66. Consequently, the image data signal is transmitted while being divided into a transfer data 1 signal and into a transfer data 2 signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus, and more particularly, to a method for forming an electrostatic latent image by scanning a recording medium such as a photosensitive member with a laser beam by an electrophotographic system such as a laser beam printer or a copying machine. And an image forming apparatus for obtaining a desired image.

[0002]

2. Description of the Related Art Conventionally, in a laser beam printer or a copying machine, a laser beam is applied by a laser exposure device (optical scanning device) on a photoreceptor uniformly charged by a charge corotron in accordance with an output image signal. By flashing and exposing, an electrostatic latent image of a digital image is formed on the photoconductor. The toner image is developed by developing the toner image, the obtained toner image is transferred onto a recording medium by a transfer corotron, and fixed by a heat roll and a pressure roll to form a digital image by a so-called electrophotographic method. .

As a light source of a laser exposure apparatus for forming a digital image on a photoreceptor, a semiconductor laser (laser diode, hereinafter referred to as LD) is generally used, and the light source is modulated according to an image to be formed. A laser beam is output. The laser beam output from the light source is
It is deflected by a rotating polygon mirror (polygon mirror) and scans the photosensitive member. As a result, an electrostatic latent image of an image to be formed on the photoconductor is formed.

In such a digital image forming apparatus, a monitor voltage obtained by converting a monitor current corresponding to an optical output into a voltage and a desired voltage reference value are successively set so as to obtain a required optical output value. In comparison, the drive current of the semiconductor laser is controlled so that the monitor voltage value matches the voltage reference value (so-called automatic optical output adjustment (APC: Auto Power).
r Contro1)). By performing the APC control, the light amount for image writing can be set to a necessary light amount, and a desired output image can be obtained.

In general, a semiconductor laser has an LED light-emitting region (natural light-emitting region) in which laser light does not oscillate until a predetermined threshold current. When a current exceeding the threshold current is supplied, the semiconductor laser increases in proportion to the current. The light output also has the characteristic of increasing linearly.

[0006] In response to recent high speed and high resolution,
The video rate (Mpixcel / sec: MHz) has also been increased, and accordingly, it has become difficult to clear the standards (VCCI, FCC, CISPR) for unnecessary radiated radio waves. Here, the resolution is 60
0DPI (Dot Per Inch) doubles to 120
If it becomes 0 DPI, the video rate is quadrupled. In other words, when the video rate is 600 MHz and the video rate is 30 MHz, the video rate is 120 MHz when the device having the same configuration is 1200 DPI. When the video rate quadruples, the level of the unnecessary radiated radio wave increases by about 12 dB.

That is, even if the standard required by 600 DPI is cleared, if the speed and resolution are to be further increased, it is impossible to clear the standard with an apparatus having the same configuration. Further, there is a problem that a great deal of cost is required to clear the standard.
In addition, as the video rate is increased, the waveform may be rounded from the time when the image data is output from the controller to the time when the image data reaches the optical scanning device, resulting in a problem that the output image is deteriorated.

In order to solve these problems, when an image data signal is output from a controller for forming image forming data to an optical scanning device, an MCU which controls the entire device.
(Main Control Unit) and a technique for directly transmitting the signal to an optical scanning device without using a main control unit, shortening the transmission distance of a high-frequency signal line, suppressing unnecessary radio waves, and reducing a transfer loss of image data have been proposed. (JP-A-5-304581).

Further, in an image forming apparatus capable of changing the resolution, even when a high resolution image data signal is transferred from the controller to the optical scanning device, the transfer frequency is transferred with the low resolution transfer frequency. Thus, a technique has been proposed for suppressing unnecessary radiated radio waves (JP-A-6-91927). Further, a technique for transmitting an image data signal by a parallel signal has been proposed (Japanese Patent Laid-Open No. 2-178067).

[0010]

However, in the technique described in Japanese Patent Application Laid-Open No. Hei 5-304581, the MCU is not used.
However, there is a problem that the lighting of the laser cannot be completely controlled.
That is, when an erroneous signal is generated from a controller that generates image data, there is a problem that the MCU cannot stop the erroneous signal and cannot control the erroneous signal. In addition, although image data is transferred by an optical fiber cable, the cost is high and there is a problem that there is a limit in shortening the data line between the controller and the optical scanning device due to a layout problem in the device. .

In the technique described in Japanese Patent Application Laid-Open No. 6-91927, the transfer frequency from the controller to the optical scanning device remains low even when the resolution is changed to a high resolution.
In order to modulate the semiconductor laser so that a desired output image is formed in the optical scanning device, a clock (oscillator) for reading data corresponding to the high resolution from a line memory in the optical scanning device is provided. Required. However, there has been a problem that the oscillating section becomes a source of unnecessary radiation waves, and unnecessary radiation waves are always generated.

In the technique described in Japanese Patent Application Laid-Open No. 2-178067, when an image data signal is transmitted by a parallel signal, the image data is stored in a line memory in an optical scanning device. When converting the stored image data into an image data signal sequence corresponding to the resolution, that is, in order to read out the image data from the stored line memory at a cycle corresponding to the resolution, an oscillating unit that outputs a video clock corresponding thereto. Or supply a video clock from another control unit. If an oscillation unit is provided, unnecessary radiated radio waves are generated in the same manner as described above, and even when a video clock is supplied from another control unit, the signal line to be transmitted must have a high-frequency signal line. There was a problem that radio waves could not be suppressed.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem, and has as its object to provide an image forming apparatus capable of suppressing unnecessary radiation waves with a simple configuration.

[0014]

In order to achieve the above object, an image forming apparatus according to the present invention divides an image data signal corresponding to an input image based on a signal obtained by dividing a video clock. Image data output means for outputting the divided signals in parallel from a plurality of signal lines, synthesizing means for synthesizing the signals output from the image data output means and generating an image data signal, Light scanning means for scanning the image carrier with a light beam modulated based on the image data signal generated by the means.

According to a second aspect of the present invention, in the image forming apparatus of the first aspect, the synthesizing means is constituted by an OR circuit or an exclusive OR circuit.

According to the first aspect of the present invention, the image data output means divides an image data signal corresponding to an input image based on a signal obtained by dividing a video clock, and divides the divided signal into a plurality of signal lines. Output in parallel. This allows
The transmission frequency of each of the divided image data signals is lower than the transmission frequency of the undivided image data signal. The synthesizing unit generates an image data signal by synthesizing the signals divided and output from the image data output unit.
This synthesizing means can be constituted by an OR circuit or an exclusive OR circuit. Therefore, it is possible to generate an image data signal by synthesizing the divided and output signals with a simple configuration. The optical scanning means scans the image carrier with a light beam modulated based on the image data signal synthesized by the synthesizing means. As described above, since the image data signal is divided based on the signal obtained by dividing the video clock and is output in parallel from a plurality of signal lines, the transmission frequency can be reduced.
Generation of unnecessary radiation waves can be suppressed.

According to a third aspect of the present invention, in the image forming apparatus of the first or second aspect, a control signal for automatically adjusting at least one of the plurality of signal lines to adjust the light amount of the light beam. It is characterized by sharing with the line.

According to the present invention, at least one of the plurality of signal lines is used as a control signal line for automatically adjusting the light amount of the light beam when the light amount is automatically adjusted, and divided at the time of image formation. It is used as a signal line for transmitting the obtained image data signal. Therefore, the number of signal lines can be reduced as compared with the case where the signal lines are not shared, and the generation of unnecessary radiation waves can be further suppressed.

According to a fourth aspect of the present invention, the number of divisions of the image data signal is increased as the resolution of the input image increases.

According to the fourth aspect of the present invention, as the resolution of the input image increases, the number of divisions of the image data signal is increased, so that generation of unnecessary radiation waves is optimally suppressed according to the resolution. Can be. A plurality of division circuits for image data signals having different numbers of divisions may be provided, and these circuits may be switched according to the resolution.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] A first embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 2 shows an image forming apparatus 1 such as an electrophotographic laser beam printer or copier to which the present invention is applied.
0 is shown.

As shown in FIG. 2, the image forming apparatus 10
The photoconductor 12 is provided, and around the photoconductor 12, a charging device 14, a developing device 16, a transfer device 18, and a cleaning device 20 are arranged. Further, the fixing device 24 including a heat roll and a pressure roll is disposed downstream of the sheet 56 in the transport direction.

An optical scanning device 30 composed of an optical scanning unit 26 and an LD driving unit 28 is disposed above the photoconductor 12, and a main controller 32 is connected to the optical scanning device 30. The image data output unit 34 is connected to 32.

The photosensitive member 12 is rotating in the direction of arrow A in FIG. 2, and is uniformly charged by a charging device (charge corotron) 14. In this uniformly charged state, the image data signal output from the image data output unit 34 is output to the optical scanning device 30 via the MCU 32, and the laser beam 38 modulated according to the image data signal is output. . The photosensitive member 12 is scanned and exposed by the laser beam 38 to form an electrostatic latent image. The electrostatic latent image formed on the photoconductor 12 is visualized by the developing device 16,
A toner image is formed on the photoconductor 12.

The toner image formed on the photoreceptor 12 is transferred by a transfer device 18 (transfer corotron) to a sheet 22 conveyed in the direction of arrow C in FIG. Thereafter, the sheet 22 is subjected to a fixing process by a fixing device 24 to obtain a final output image. On the other hand, the photoconductor 12
The unnecessary toner is cleaned by the cleaning device 20 to prepare for the next image output.

The optical scanning unit 26 has an LD 36 as shown in FIG. The LD 36 is an LD driving unit 2
8 and the MCU 3 from the image data output unit 34
2 outputs a laser beam 38 modulated in accordance with the image data output to the LD drive unit 28 via the laser beam 38.

Laser beam 38 output from LD 36
Is an arrow B in FIG.
The light enters the reflecting surface of the polygon mirror 42 rotating at a predetermined speed in the direction, and is deflected. The deflected laser beam 38 passes through the fθ lens 44, is turned back by the plane mirror 46, and is further turned by the cylindrical mirror 48 to the photosensitive member 12
, And scans and exposes the surface of the photoconductor 12. It should be noted that the scanning start side of the laser beam 38 is SOS
A (Start Of Scan) sensor 50 is provided, and when the laser beam 38 turned back by the plane mirror 46 and the plane mirror 54 is incident on the SOS sensor 52, modulation of the laser beam 38 is started. Therefore, SO
Writing of an image is started when a predetermined time has elapsed after the detection of the laser beam 38 by the S sensor 52. As described above, by detecting the laser beam 38 by the SOS sensor 52, horizontal synchronization is obtained for each line,
Determine the image writing timing.

At this time, the emission power of the laser beam 38 is set to a value of a light output necessary for image formation on the photoreceptor 12 by controlling a current for driving the LD 36 by the LD drive unit 38. You. Specifically, a monitor current corresponding to the optical output is output from the LD 36 to the LD drive unit 28, and the LD drive unit 28 converts the monitor current into a voltage,
This is fed back to U32 as a monitor voltage. MCU
At 32, the monitor voltage is sequentially compared with a desired voltage reference value Vref required for image formation on the photoconductor 12, and a drive current setting voltage value such that the monitor voltage matches the voltage reference value Vref is LD-driven. Output to the unit 28. And L
The D driving unit 28 controls the LD 36 according to the driving current setting voltage value.
Set the drive current of For example, when the required light output on the photoconductor 12 is 0.5 mW, the monitor voltage is 3 V
In this case, LD3 is set so that the monitor voltage becomes 3V.
6 is set. By performing the feedback control (APC control) in this manner, the drive current of the LD 36 is optimally set, and the amount of light required for image formation on the photoconductor 12 can be set. Note that the voltage reference value Vref may be output from the MCU 32 to the LD driving unit 28, and the LD driving unit 28 may perform feedback control.

Next, the configuration of the image data output unit 34 will be described.

FIG. 1 shows a schematic configuration of the image data output section 34.

As shown in FIG. 1, the image data output unit 34
Is composed of JK flip-flop circuits 60 and 62 and AND circuits 64 and 66. The J terminal, the CLEAR terminal, and the preset terminal of the JK flip-flop circuit 60 are connected to a constant voltage (for example, 5 V) power supply (not shown). The inverted K terminal of the JK flip-flop circuit 60 is grounded, and a video clock is input to a clock (CK) terminal from an oscillator (not shown). That is, the J terminal is always at the high level (1), and the inverted K terminal is always at the low level (0).

On the other hand, J of the JK flip-flop circuit 62
The terminal, the clear terminal, and the preset terminal are connected to a not-shown constant voltage (for example, 5 V) power supply. Also, JK
The inverted K terminal of the flip-flop circuit 62 is grounded, and the clock terminal is connected to the Q terminal of the JK flip-flop circuit 60. That is, the J terminal is always at the high level (1), and the inverted K terminal is always at the low level (0).
It is. The Q terminal of the JK flip-flop circuit 62 is AN
Connected to one input terminal of the D circuit 64,
The terminal is connected to one input terminal of the AND circuit 66. The other input terminal of the AND circuit 64 and the AND circuit 6
6 is connected to an image data signal (VIDEO D
ATA) is input.

Next, the operation of this embodiment will be described with reference to the timing chart shown in FIG.

First, when the video clock (pulse of one dot cycle corresponding to the resolution) shown in FIG. 4A is input to the CK terminal of the JK flip-flop circuit 60, the J terminal is always at the high level and inverted K Since the terminal is always at the low level, a signal that is inverted every dot, such as the Q1 signal shown in FIG. 4B, is obtained from the Q terminal. That is, a signal obtained by dividing the video clock by two is obtained.

When the Q1 signal is input to the CK terminal of the JK flip-flop circuit 62, the J terminal is always at the high level and the K terminal is always at the low level. A signal that is inverted every two dots, such as the Q2 signal, is obtained. That is, the video clock is set to 4
A divided signal is obtained.

Using the Q2 signal and the inverted Q2 signal output from the inverted Q terminal of the JK flip-flop circuit 62 as shown in FIG. 4D, an image data signal as shown in FIG. To divide. That is, the AND circuit 64 performs an AND operation between the Q2 signal and the image data signal, and
A transmission data 1 signal as shown in (F) is output to the MCU 32. The AND circuit 66 performs an AND operation on the inverted Q2 signal and the image data signal and outputs a transmission data 2 signal as shown in FIG.

The image data divided by the image data output unit 34 in this way is transmitted to the optical scanning device 30 via the MCU 32. The image data signal divided and transmitted in this manner is supplied to the LD driving unit 28 of the optical scanning device 30 by an OR circuit (not shown) or EXCLUSIVE_O.
The signal is synthesized by the R circuit into a signal as shown in FIG.
The laser is modulated according to the combined image data.

Therefore, even when transmitting image data having an inherently high transmission frequency such as repeating on / off for each line from the image data output section 34 to the optical scanning device 30, the image data signal is divided into two. The transmission frequency can be reduced to half.
Also, the OR circuit or EXCLUS is used in the optical scanning device 30 without using a clock that causes unnecessary radiation.
Since the image data signal is synthesized only by the IVE_OR circuit, the generation of unnecessary radiation waves can be suppressed with a simple configuration.

When the MCU 32 performs the above-described APC control on the optical scanning device 30 for each page, M
The drive current setting voltage output from the CU 32 is held while image formation for one page is performed. That is, only a constant voltage is output from the MCU 32 to the LD drive unit 28. Further, the MCU 32 outputs the voltage reference value Vref to the LD driving unit 28 to output the voltage reference value Vref to the LD driving unit 2.
Even when the APC control is performed in step 8, if intensity modulation or the like is not performed in the line, the hold is performed while the image formation for one page is performed. Similarly, in the case where APC control is performed for each line, not for each page, the drive current setting voltage or the voltage reference value Vref becomes a constant value during image formation for one line.

Therefore, the control signal line from which the drive current setting voltage or the voltage reference value Vref is output and the divided image data signal line may be shared.

For example, as shown in FIG. 7, when the APC control is performed for each page, the signal line 90 is used for outputting the drive current setting voltage, and the signal line switching section 92 controls the drive setting. The current value is output to the laser driver 94. Then, when the APC control ends, the drive current setting voltage is output to the holding unit 96. During image formation, the holding unit 96
Outputs the drive current setting voltage to the laser drive unit 94, and the signal line 90 is used for the transmission data 2 signal. The same applies to the case where the MCU 32 outputs the voltage reference value Vref.

As described above, by outputting the drive current setting voltage and the transmission data 2 signal using the common signal line,
The number of signal lines connecting the MCU 32 and the LD drive unit 28 can be reduced as compared with the case where the signal lines are not shared. For this reason, unnecessary radiation waves can be further reduced as compared with the case where the signal line is not shared. Second Embodiment Next, a second embodiment will be described in detail with reference to the drawings.

FIG. 5 shows a schematic configuration of the image data output section 34 '. The same parts as those of the image data output unit 34 shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 5, the image data output unit 34 '
Has a JK flip-flop circuit 68,
The J terminal, the clear terminal, and the preset terminal of the flip-flop circuit 68 are connected to a constant voltage (for example, 5 V) power supply (not shown). The inverted K terminal is grounded, and the Q terminal of the JK flip-flop circuit 62 is connected to the clock terminal. JK flip-flop circuit 6
The second Q terminal is connected to one input terminal of the AND circuit 70 and the AND circuit 74, and the inverted Q terminal is connected to one input terminal of the AND circuit 72 and the AND circuit 76.

The Q of the JK flip-flop circuit 68
The terminal is connected to the other input terminals of the AND circuit 70 and the AND circuit 72, and the inverted Q terminal is connected to the AND circuit 74.
And the other input terminal of the AND circuit 76. The output terminals of the AND circuits 70, 72, 74, 76
AND circuits 78, 80, 82, 84 are respectively connected to one input terminals of the AND circuits 78, 80, 82, 8
Image data is input to the other input terminal 4.

First, when the video clock (pulse of one dot cycle corresponding to the resolution) shown in FIG. 6A is input to the CK terminal of the JK flip-flop circuit 60, the J terminal is always at the high level and the inverted K Since the terminal is always at the low level, a signal that is inverted every dot, such as the Q1 signal shown in FIG. 6B, is obtained from the Q terminal. That is, a signal obtained by dividing the video clock by two is obtained.

When the Q1 signal is input to the CK terminal of the JK flip-flop circuit 62, the J terminal is always at the high level and the K terminal is always at the low level. A signal that is inverted every two dots, such as the Q2 signal, is obtained. That is, the video clock is set to 4
A divided signal is obtained.

When the Q2 signal is input to the CK terminal of the JK flip-flop circuit 68, a signal inverted every four dots, such as the Q3 signal shown in FIG. 6D, is obtained. That is, a signal obtained by dividing the video clock by 8 is obtained.

Using the Q2 signal, the Q3 signal, the inverted Q2 signal output from the inverted Q terminal of the JK flip-flop circuit 62, and the inverted Q3 signal output from the inverted Q terminal of the JK flip-flop circuit 68, FIG. The image data signal as shown in FIG.

That is, the AND circuit 70 outputs an AND signal obtained by ANDing the Q2 signal and the Q3 signal to the AND circuit 78, and the AND circuit 78 performs an AND operation on the AND signal and the image data signal, as shown in FIG. A transmission data 1 signal as shown in (F) is output to the MCU 32.

The AND circuit 72 outputs an AND signal obtained by ANDing the inverted Q2 signal and the Q3 signal to the AND circuit 80. The AND circuit 80 ANDs the AND signal with the image data signal. 6 (G) is output to the MCU 32.

The AND circuit 74 outputs an AND signal obtained by ANDing the Q2 signal and the inverted Q3 signal to the AND circuit 82. The AND circuit 82 ANDs the AND signal with the image data signal. The transmission data 3 signal as shown in FIG.

The AND circuit 76 outputs an AND signal obtained by ANDing the inverted Q2 signal and the inverted Q3 signal.
The AND circuit 84 performs an AND operation on the AND signal and the image data signal to output a transmission data 4 signal as shown in FIG.

The image data divided into four by the image data output section 34 'is transmitted to the optical scanning device 30 via the MCU 32. The image data signal divided and transmitted in this manner is supplied to the LD driving unit 28 of the optical scanning device 30 by an OR circuit (not shown) or EXCLUSIVE_
The signal is combined by the OR circuit into a signal as shown in FIG. 6 (J), and the laser is modulated according to the combined image data.

Therefore, for example, when transmitting image data having an inherently high transmission frequency that repeats on / off for each line from the image data output section 34 'to the optical scanning device 30, the image data signal is divided into four parts. Then, the transmission frequency can be suppressed to. Also, the OR circuit or EXCL can be used in the optical scanning device 30 without using a clock that causes unnecessary radiation.
Since the image data signals are synthesized only by the USIVE_OR circuit, the generation of unnecessary radiation waves can be suppressed with a simple configuration. Also, if the period of one dot is shortened by increasing the transmission speed, the laser output becomes thinner due to the influence of the rise time and fall time of the image data signal, and the output in the main scanning direction is therefore reduced. Although the ratio of vertical and horizontal lines (aspect ratio) becomes worse, the transmission frequency is reduced by dividing the image data signal as described above,
By using a pulse having a long cycle, it is possible to prevent the output image from deteriorating due to the rounding or narrowing of the waveform of the image data signal.

When the resolution can be switched, the number of lines of the image data signal may be switched according to the selected resolution. For example, when the resolution is 600 DPI, the image data is divided and transmitted using two lines of the image data signal, and when the resolution is 1200 DPI, four lines of the image data signal are transmitted.
This is used to divide the image data and transmit it. Further, a circuit for dividing the image data may be switched according to the selected resolution. For example, if the resolution is 600DP
In the case of I, the circuit is switched to a circuit for dividing the image data signal into two, and when the resolution is 1200 DPI, the circuit is switched to a circuit for dividing the image data signal into four. Also, in the above description, the image data signal is divided into two in the case of 600 DPI, but the invention is not limited to this. The number of divisions of the image data signal is determined by the process speed of the device and the standard of unnecessary radiated radio waves that must be cleared. In consideration of the above, the number of divisions can be freely selected.

[0058]

As described above, according to the first aspect of the present invention, the image data output means divides an image data signal corresponding to an input image based on a signal obtained by dividing a video clock. Since the divided signals are output in parallel from the plurality of signal lines, the transmission frequency of each of the divided image data signals is reduced, and the generation of unnecessary radiation waves can be suppressed. .

According to the second aspect of the present invention, since the synthesizing means is constituted by an OR circuit or an exclusive OR circuit, the divided image data signals can be synthesized with a simple configuration. Has the effect of

According to the third aspect of the present invention, at least one of the plurality of signal lines is shared with a control signal line for automatically adjusting the light amount of the light beam. Thus, the number of signal lines can be reduced, and the generation of unnecessary radiation waves can be further suppressed.

According to the fourth aspect of the invention, the number of divisions of the image data signal is increased as the resolution of the input image increases, so that the generation of unnecessary radiated radio waves is optimally suppressed according to the resolution. Has the effect of being able to

[Brief description of the drawings]

FIG. 1 is a circuit diagram of an image data output unit according to a first embodiment.

FIG. 2 is a schematic configuration diagram of an image forming apparatus.

FIG. 3 is a schematic configuration diagram of an optical scanning unit.

FIG. 4 is a timing chart showing operation timings of an image data output unit according to the first embodiment.

FIG. 5 is a circuit diagram of an image data output unit according to a second embodiment.

FIG. 6 is a timing chart illustrating operation timings of an image data output unit according to the second embodiment.

FIG. 7 is a schematic configuration diagram of an image forming apparatus.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 image forming device 12 photoreceptor 14 charging device 16 developing device 18 transfer device 20 cleaning device 22 paper 24 fixing device 26 optical scanning unit 28 LD drive unit 30 optical scanning device 32 MCU 34 image data output unit 60, 62 JK flip-flop circuit 64, 66 AND circuit

Claims (4)

[Claims] An image data output means for dividing an image data signal corresponding to an input image based on a signal obtained by dividing a video clock, and outputting the divided signal in parallel from a plurality of signal lines; Combining means for combining the signals divided and output from the output means to generate an image data signal; and scanning the image carrier with a light beam modulated based on the image data signal generated by the combining means. An image forming apparatus comprising: a light scanning unit. 2. The image forming apparatus according to claim 1, wherein the synthesizing unit includes an OR circuit or an exclusive OR circuit. 3. The method according to claim 2, wherein at least one of the plurality of signal lines includes:
The image forming apparatus according to claim 1, wherein the image forming apparatus is shared with a control signal line for automatically adjusting a light amount of the light beam. 4. The image forming apparatus according to claim 1, wherein the number of divisions of the image data signal is increased as the resolution of the input image increases.