Controlling The Developing Bias - Canon GP405 Service Manual

B. Controlling the Developing Bias
1. Outline
A DC bias and an AC bias are applied to the developing cylinder. The output is controlled by
the composite power supply PCB according to control signals from the image processor PC for the
following:
• Turning on and off the developing bias AC component.
• Turning on and off the developing bias DC component.
• Turning on and off the developing bias DC component.
AC power supply voltage input
DC bias ON signal
(HVDCEN*)
J103B
DC bias mode signal(HVDCSL*)
J103B
Serial communication
DC bias level signal
J103A
AC bias ON signal(HVACEN*)
J103B
COPYRIGHT © 1999 CANON INC. CANON 405/335 REV.0 JAN. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)
Composite power supply PCB
High-voltage
main transformer
Transformer
(DC component)
drive signal
J209B
DC bias control signal
J209B
J209A
Transformer
drive signal
J209B
Figure 6-201
CHAPTER 6 IMAGE FORMATION SYSTEM
Voltage
Output control
detection
Voltage value
High-voltage
transformer for
development
(AC component)
Developing
cylinder
Photosensitive
+
drum
DC bias
AC bias
6-17