High Voltage Power Supply Circuit - Canon GP160DF Service Manual

CHAPTER 9 EXTERNAL/AUXILIARY MECHANISM
2. Protection function
There is an overcurrent / overvoltage protective function located on the DC power
supply PCB, which automatically interrupts the output voltage. This is to protect the DC
power supply circuit from damage which may occur from problems such as a short in
the electrical load, which can cause an overcurrent or overvoltage.
When the overcurrent / overvoltage protective function is activated, turn off the
power supply switch, and once the electrical load trouble has been rectified, turn the
power switch on again to restart.
Also, there are two fuses which have been built into the internal circuit. Should an
overcurrent occur in the AC line, the fuses blow, and the flow of electricity is cut off.
B.

High voltage power supply circuit

The high voltage power supply circuit is built into the DC controller PCB.
At designated times, the DC controller PCB's CPU (IC301) emits instructions to gen-
erate the high voltages listed below.
• Primary charge roller applied voltage (AC voltage + DC positive voltage)
• Developing bias (AC voltage + DC negative voltage)
• Transfer charge applied (DC positive voltage as well as DE negative voltage)
• Static charge eliminator bias (DC negative voltage)
Please refer to chapter 6 "Image formation system" for more information regarding
the control of each electrical load.
9-4
COPYRIGHT © 1999 CANON INC. CANON GP160 REV.0 FEB. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)