Basic Operation; Outline Of The Electrical System - Canon DU-82 Service Manual

I. BASIC OPERATION
A. Outline of the Electrical System
The duplexing unit inverts the print paper and feeds it to the printer.
The duplexing unit is controlled with various commands sent from the DC controller PCB in
the printer.
The duplexing driver PCB controls the sequence of duplexing unit operations. The duplexing
driver PCB has a four-bit microcomputer (CPU, IC2002) which controls the sequence of duplex-
ing unit operations and serially communicates with the DC controller PCB in the printer.
The CPU drives motors, solenoids, and a clutch according to the duplex unit specification
command and the duplex pick-up command sent from the DC controller PCB.
The printer provides +24 VDC to the duplexing unit. The duplexing driver PCB generates +5
V for ICs and sensors from +24 V.
The flow of signals between the duplexing unit and printer is shown below.
Duplexing unit
PS24
paper sensor
Reversing sensor
PS26
Side registration
guide home PS25
position sensor
Duplex feed roller
1 home position PS23
sensor
CPU
IC2002
Duplexing
driver PCB
Serial line
+24VA
DC controller
PCB
Printer
Figure 2-1-1
CHAPTER 2
M8
Duplexing unit
motor
Side registration
M7
motor
Reversing roller
SL7
release solenoid
Duplex deflector
SL6
solenoid
Duplex feed cluch
CL5
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