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Various Controls
Controlling the Laser Activation Timing
Laser ON/OFF Control
Laser ON/OFF control is dependent on the combination of the laser control signal (A/B laser: CNT1-0/1-1/1-2, C/D laser: CNT0-0/0-1/0-2) from the image PCB.
<A laser/B laser>
Laser control signal
Laser status
CNT1-2
CNT1-1
CNT1-0
A Laser
B Laser
0
1
0
ON (For APC control)
OFF
0
1
1
OFF
OFF
0
0
1
OFF
ON (For APC control)
0
1
1
OFF
OFF
1
1
1
Video signal entry arrowed
Video signal entry arrowed
0
1
1
OFF
OFF
0
0
1
OFF
ON (For APC control)
0
1
1
OFF
OFF
<C laser/D laser>
Laser control signal
Laser status
CNT1-2
CNT1-1
CNT1-0
C Laser
D Laser
0
0
1
ON (For APC control)
OFF
0
1
1
OFF
OFF
0
1
0
OFF
ON (For APC control)
0
1
1
OFF
OFF
1
1
1
Video signal entry arrowed
Video signal entry arrowed
0
1
1
OFF
OFF
0
0
1
OFF
ON (For APC control)
0
1
0
OFF
OFF
Main Scanning Synchronous Control
Main scanning synchronous control is operated at synchronous PCB based on BD synchronous signal.
Based on BD signal that is formed from A laser light detected by BD PCB, BD synchronous signal for each laser is formed inside image PCB.
Image data written in the line memory is read out by the readable signal (RE_A, RE_B, RE_C, RE_D) according to the 4 phase differences formed inside the delayPCB based on the BD synchronous signal (BD_SYNCH) and is sent to the laser driver.
[1] Synchronous PCB
[4] VDO
[2] Delay PCB
[5] VDO signal process unit
[3] Line memory
[6] Laser driver PCB
BD_SYNCH: BD synchronous signal
RE_A/B/C/D: Readable signal
MEMO:
Regarding BD signal formation
Not B laser but A laser only reaches BD sensor on BD PCB. BD signal is formed based on A laser light.