Developing Bias Control Circuit - Canon NP6045 Service Manual

CHAPTER 4 IMAGE FORMATION SYSTEM

3. Developing Bias Control Circuit

The circuit that controls the developing bias is equipped with the following functions:
a. Turing the AC bias ON and OFF.
b. Controlling the DC bias to a specific level.
Turning OFF the AC Bias
The developing bias remote signal ACBTP is '0'.
The AC bias switch circuit turns OFF.
The drive circuit turns OFF.
The AC transformer (T401) output stops.
The above condition stops the AC bias to the developing cylinder.
Turning ON the AC Bias
The developing bias remote signal ACBTP is '1'.
The drive circuit turns ON.
The AC bias switch circuit turns ON.
The above condition causes the voltage to be increased to 1500 Vp-p and sent
to the developing cylinder.
DC controller
PCB
Q156
J114A J202
-3 -8
ACBTP
J114A J202
(master)
-10 -1
Micro-
processor
DCBTP
J114A J202
-1 -10
ROED
D/A
J114A J202
converter
-2 -9
DCBC
4-32
COPYRIGHT © 1997 CANON INC.
High-voltage transformer (HVT)
AC transformer
Switching Drive
circuit circuit
Switching
circuit
Figure 4-208
High voltage detection
AC wave
generation
DC transformer
Drive
circuit
CANON NP6045 REV. 1 MAR. 1997 PRINTED IN JAPAN (IMPRIME AU JAPON)
Developing
Drum
cylinder
Roller
electrode