Primary Charging Roller Bias Control - Canon NP6512 Service Manual

CHAPTER 4 IMAGE FORMATION SYSTEM
C.

Primary Charging Roller Bias Control

1. Outline
Figure 4-103 shows the circuit used to control the voltage applied to the primary charging
roller, and has the following functions:
• Turning on and off the DC bias.
• Controls the DC bias to a constant voltage.
• Switching the level of the DC bias.
• Corrects the level of the DC bias automatically.
The level of the DC bias applied to the primary charging roller is switched between image area
and non-image area.
Reference:
The level of the DC bias is as follows:
Image area: -1376 V ± (correction value by APVC) ± (correction value * by density mode)
Non-image area: -900 V ± (correction value by APVC); area between sheets
-1000 V ± (correction value by APVC); cleaning area by transfer
-600 V ± (correction value by APVC); trailing edge area
*See p. 4-16.
4-4
COPYRIGHT © 1999 CANON INC. CANON NP6512/6612/7120/7130/7130F REV.0 AUG. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)