3. Developing Bias Control Circuit
The circuit used to control the developing bias is provided with the following
functions:
a. Turning on and off the AC bias
b. Controlling the voltage level of the DC bias
q
AC Bias OFF control developing bias remote signal ACBTP is ‘0’
AC bias switch circuit goes OFF.
Drive circuit goes OFF.
AC transformer T401 output is cut off.
The above condition deprives the developing cylinder of AC bias.
The above condition stops the AC bias to the developing cylinder.
w
AC bias ON control developing bias remote signal ACBTP is ‘1’
Drive circuit goes ON.
AC bias switch circuit goes ON.
The above condition causes the high-voltage transformer to increase the high-
voltage transformer to 1500 Vp-p and supply it to the developing assembly.
Figure 4-208
DC controller
PCB
Q156
(master)
Micro-
processor
D/A
converter
Switch
circuit
Drive
circuit
Switch
circuit
Drive
circuit
DC transformer
T402
AC wave
generation
AC transformer T401
High-voltage transformer (HVT)
Voltage detection
Drum
J114
A-3
J202
-8
J114
A-10
J202
-1
J114
A-1
J202
-10
J114
A-2
J202
-9
ACBTP
DCBTP
ROED
DCBC
Developing
cylinder
Roller
electrode
COPYRIGHT © 1997 CANON INC. CANON NP6350/NP6251 REV. 0 JULY 1997 PRINTED IN JAPAN (IMPRIME AU JAPON)
CHAPTER 4 IMAGE FORMATION SYSTEM
4-35
