Main Scanning Synchronous Control; Controlling The Intensity Of Laser Light; Apc Control - Canon iR3245 Series Service Manual

6.3.1.2 Main Scanning Synchronous Control

iR3225 / iR3225N / iR3235 / iR3235N / iR3245 / iR3245N
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 delay
PCB based on the BD synchronous signal (BD_SYNCH) and is sent to the laser driver.
J462
Image PCB
[1] Synchronous PCB
[2] Delay PCB
[3] Line memory
[4] VDO
[5] VDO signal process unit
[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.

6.3.2 Controlling the Intensity of Laser Light

6.3.2.1 APC Control

iR3225 / iR3225N / iR3235 / iR3235N / iR3245 / iR3245N
The machine monitors the laser light that is emitted to the built-in photo diode of laser diode and adjusts the laser to appropriate intensity.
[6]
[1]
BD_SYNCH
RE_A
[2]
[3]
RE_B
[2]
[3]
RE_C
[2]
[3]
RE_D
[2]
[3]
[5]
J461
[4]
F-6-5
Main controller
PCB
Chapter 6
0019-4285
0019-4286
6-5