Roller Electrode Bias Control Circuit - Canon NP6251 Service Manual

CHAPTER 4 IMAGE FORMATION SYSTEM
DC bias voltage level control
The voltage of the DC bias is determined by the signal (DCBC) from the DC
controller.
• High-voltage DC remote signal (DCBTP) = 1
• Roller bias remote signal (ROED) = 1
• Developing DC control signal (DCBC) = 3 V or more or less than 12 V
The above condition turns on the AC bias switch circuit; when the output (DCBC)
from the DC controller PCB increases, the output of DC bias will also increase.

4. Roller Electrode Bias Control Circuit

The circuit used to control the roller electrode bias is equipped with the following
functions:
a. Turning on and off the roller electrode.
Roller electrode ON signal
• High-voltage DC remote signal (DCBTP) = 1
Roller bias signal (ROED) = 1
Switch circuit goes ON
High-voltage transformer drive circuit goes ON
DC transformer T402 goes ON
The above condition supplies the roller electrode with a bias of about 1000 V; the
DC bias is not controlled to a specific voltage.
4-36
COPYRIGHT © 1997 CANON INC.
DC bias voltage level
(V)
600
0
3
DCBC signal input voltage (V)
Figure 4-209
CANON NP6350/NP6251 REV. 0 JULY 1997 PRINTED IN JAPAN (IMPRIME AU JAPON)
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