Canon imageRUNNER ADVANCE C5255, Service Manual, Page: 73 / 1443

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Technology > Laser Exposure System > Various Controls > Vertical Scanning Synchronous Control
Technology > Laser Exposure System > Various Controls > Vertical Scanning Synchronous Control
VDO_Y
VDO_M
VDO_C
VDO_Bk
Laser Scanner Unit 1
Laser Scanner Unit 2
BD Sensor (Y, M)
BD Sensor (C, Bk)
BD_CBk
BD_YM
DC
Controller (UN1)
Main Controller
Y Laser Driver
PCB
Y Laser
M Laser
C Laser
Bk Laser
M Laser Driver
PCB
C Laser Driver
PCB
Bk Laser Driver
PCB
VDO
VDO
VDO
VDO
VDO_Y
VDO_M
VDO_C
VDO_Bk
Reference DB
F-2-50
F-2-51
■
Vertical Scanning Synchronous Control
● Purpose
This is to align the writing start position in vertical scanning direction.
● Execution timing
Per printing
● Execution time
500ms
● Control detail
1) When DC Controller receives the print instruction, it detects the reference signal.
Based on this signal, it creates the vertical scanning synchronous signal (PVREQ) and
sends to Main Controller.
2) Main Controller is synchronized with PVREQ signal and sends VDO signal to DC Cotnroller.
3) DC Controller creates the laser drive signal based on VDO signal and sends it to the Laser
Scanner Unit. The Laser Scanner Unit conform the image leading edge with the paper
leading edge by emitting the laser in this timing.
Laser Laser Laser Laser
VDO
PVREQ
2) 3)
DC Controller
(UN1)
Main
Controller2
Print
instruction
Laser drive signal
1)
Reference
Signal
F-2-52