Engine Control System; Dc Controller Circuit - Canon LBP 2460 - B/W Laser Printer Service Manual

CHAPTER 2
II. ENGINE CONTROL SYSTEM
A. DC Controller circuit
1. Outline
Operation sequences of the printer are controlled by the CPU of this circuit. When DC power is
supplied from the power supply by turning ON the power switch of the printer and the printer
enters the standby mode, the CPU outputs the signals that drive the loads such as laser diode,
motors, and solenoids, based on the print start command and image data.
The layout of major ICs is shown by Figure 2-2-1, and block diagram, Figure 2-2-2.
2. Explanation of operations of each block
a. CPU (IC201)
An 8-bit single chip microcomputer (HD6433388A79F) by Hitachi is used.
The CPU is a one-chip type in which ROM and RAM are built in, and controls the operation of
the engine according to the control program stored in the ROM.
b. Expansion I/O (IC203)
Its functions are to control:
1) each sensor,
2) each motor,
3) each solenoid, and
4) each clutch.
c. Gate array (IC205)
Its functions are to:
1) control the laser/scanner,
2) control the video interface, and
3) communicate with the envelope feeder.
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