Canon NP6218, FY8-13EX-000 service manual Tfwon Tfwpwm Tfws Trevon

CHAPTER 4 IMAGE FORMATION SYSTEM

Figure 4-113 shows the circuit used to control the foregoing three types of bias; the circuit has the following functions:

•turns on and off the transfer roller bias

•controls the transfer bias to a constant voltage

•controls the correction of the transfer bias voltage level

						Photosensitive
24V		Composite power supply PCB				drum
DC power
supply
assembly						Transfer roller
	Transfer
24V
	bias
	control		T402			Transformer
	circuit
						circuit
		Constant	Current	Constant	Current	Cleaning bias
		voltage control	limiter circuit	current circuit	limiter circuit
						control circuit
		circuit	(transfer bias)	(ATVC)	(cleaning)
TFWON*	TFWPWM	TFWS				TREVON*
		Microprocessor (Q512)

DC controller PCB

Microprocessor (Q301)

Figure 4-113

4-14 COPYRIGHT © 1997 CANON INC. CANON NP6218 REV. 0 MAY 1997 PRINTED IN JAPAN (IMPRIME AU JAPON)