Canon NP6621 Service Manual page 98

OPERATIONS AND TIMING
Figure 3-306 shows the circuit that controls the
foregoing three types of biases, and the circuit has
the following functions:
24V
DC
Transfer
power
24V
bias control
supply
3–42
Composite power supply PCB
circuit
T5
Constant Current
voltage control limiter circuit
circuit (transfer bias)
Microprocessor
DC controller PCB
Microprocessor (Q301)
COPYRIGHT © 1998 CANON INC.
• Turns ON/OFF the transfer roller bias.
• Controls the transfer bias to a constant volt-
age.
• Corrects the voltage level of the transfer bias.
Constant Current
current circuit limiter circuit
(ATVC) (cleaning)
Figure 3-306
CANON NP6621 REV.0 FEB. 1998 PRINTED IN JAPAN (IMPRIME AU JAPON)
Photosensitive
drum
Transfer roller
Transformer
circuit
Cleaning bias
control circuit