Canon LBP 2460 Service Manual - Page 112

CHAPTER 2 B. Operation Outline DC Controller Video Controller PCB PCB Option Controller PCB Paper deck driver PCB Serial line /VSYNC /PDLV /PFED RETURNBACK (GND) CPU (IC101) S-RAM (IC110) +5V GND Serial line PWRON GND Figure 2-7-3 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. 2 - 66