Video Interface Control - Canon LBP-1000 Service Manual

E. Video Interface Control
1. Outline
The video controller continually monitors the printer by communicating with the engine con-
troller using the video interface. The video controller outputs the video signal through the video
interface when the printer is ready to print.
The engine controller draw an image on the photosensitive drum by turning the laser
ON/OFF based on the video signal output from the video controller, and then transfer the image
onto paper to output it.
This section describes the types of the interface signals between the engine controller and
video controller PCB, and also discusses the operation sequences using the interface signals.
a. System block diagram
Printer
Engine controller
b. Video interface signal
Engine controller PCB
External device (host computer, etc.)
Video controller
Video interface signal
(see Figure 2-2-9)
Intermediate PCB
BD INPUT signal
BD PCB
Figure 2-2-8
Intermediate PCB
/RESET
/BD
SCLK
SC
Figure 2-2-9
VIDEO signal
(/BDI) (/VDO, VDO)
Laser
driver
Video controller PCB
/RESET
/BD
SCLK
SC
/VDO
VDO
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