Operation Outline - Canon LBP 2460 - B/W Laser Printer Service Manual

CHAPTER 2
B. Operation Outline
DC Controller Video Controller
PCB PCB
The video controller supplies a +5V power supply to the option controller when the printer power
is turned ON, and communication between them commences after a specified period of time.
The video controller sends the status of pick-up source and paper size for each page printed to
the option controller. The paper feeding condition of the paper deck is sent from the option
controller back to the video controller.
The microcomputer (CPU) on the option controller sends a power ON (PWRON) signal to the
paper deck, turning the paper deck's power ON. Following this, the option controller and the
paper deck commence serial communication.
The option controller sends pick-up and delivery command data for each page printed to the
paper deck based on data and the vertical synchronized signal (/VSYNC) from the video
controller along with paper feed (/PFED) and paper delivery (/PDLV) signals output from the DC
controller. The paper deck then returns its paper feed status back to the option controller.
The S-RAM (IC110) constantly stores the latest 40 pages of communication data allowing the
CPU to control the paper deck paper feed in real time for each page printed. The video controller
monitors the paper feed status of the paper deck in real time by obtaining S-RAM information
via the option controller interface.
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Option Controller
Serial line
/VSYNC
/PDLV
/PFED
RETURNBACK (GND)
GND
Figure 2-7-3
PCB
Serial line
CPU
(IC101)
PWRON
S-RAM
(IC110)
+5V
GND
Paper deck driver
PCB