Canon imagePRESS 1135 Series Service Manual page 74

2
Technology > Laser Control System > Various Controls > Main scanning synchronous control
■ Main scanning synchronous control
Purpose To align the write start position in main scanning direction
Execution timing Per 1 scan
Execution time Approx. 7.5µs
Operation 1) DC controller forcibly emits the laser diode of LaserA on the laser driver
PCB by setting the Laser control signal of LaserA to APC mode.
2) There is the BD PCB on the scanning path of LaserA and the laser beam
enters the BD PCB.
3) When the BD PCB detects the laser beam of LaserA, it generates the
reference BD signals and sends them to the DC controller.
4) DC controller sends these reference BD signals as main scanning
synchronous signals (BD) per 4-line to the main controller.
5) When the main controller receives these signals, it sends the video
signals (VDO_A, VDO_B, VDO_C, VDO_D) to the DC controller after
7.5µs.
This enables the laser driver to emit the laser beam par 4 lines from a
consistent position.
Reference
BD signal
BD
VDO_A
Main
DC controller
controller
VDO_B
VDO_C
VDO_D
Reference BD
VDO_A
VDO_B
VDO_C
VDO_D
2 Technology > Laser Control System > Various Controls > Main scanning synchronous control
BD PCB
Scanner mirror
Laser A
Laser B
Laser driver
PCB
Laser C
Laser D
T
Video Signal
Video Signal
Video Signal
Video Signal
F-2-29
T-2-20
F-2-28
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