Controlling Synchronization In Main Scanning Direction - Canon iR C3380 series Service Manual

Chapter 6
[1] 1 pixel

6.2.1.2 Controlling Synchronization in Main Scanning Direction

/ / / / iR C3380i / iR C3380 / iR C2880i / iR C2880
The machine controls synchronization in main scanning direction to ensure the write start position of individual lines in main scanning direction.
Synchronization occurs for each line of each color, and is controlled by the DC controller.
The following is the sequence of operation:
1) The DC controller sets the Bk laser control signal to APC mode (LC_CTLP4(0)=0, LC_CTLP4(1)=1), thus forcing the laser diode of the Bk driver circuit to go
on.
2) The laser beam path is equipped with a BD circuit used to receive the beam.
3) The BD circuit detects the laser beam, generates the reference BD signal (BD RAW1), and sends the result to the DC controller.
4) In response, the DC controller sends these reference BD signals to the main controller in the form of the main scanning sync signals (BD Y, BD M, BD C, BD Bk).
5) When these signals arrive, the main controller sends video signals (VDO Y, VDO M, VDO C, VDO Bk) to the DC controller a specific period of time thereafter;
as a result, the respective laser drivers go on to emit laser beams that will scan the surface of the photosensitive drum starting at a specific point of individual
lines. (See Notes.)
6-4
[1]
600DPI
1/2
1/2
Drum
1200DPI
1/2
F-6-3
Laser Driver
0013-8533