Canon imageRUNNER 1750 Series Service Manual page 66

2
Technical Explanation > Laser Exposure System > Various Controls > Controlling the Laser Activation Timing
● 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.
[6]
J8143
[1]
BD_SYNCH
RE_A
[2]
RE_B
[2]
RE_C
[2]
RE_D
[2]
[5]
Main Controller PCB
2 Technical Explanation > Laser Exposure System > Various Controls > Controlling the Laser Activation Timing
J8142
[3]
[3]
[4]
[3]
[3]
F-2-60
[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
NOTE:
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.
2-38
2-38