Controlling The Developing/Separation Static Eliminator Bias - Canon NP6412 Service Manual

CHAPTER 4 IMAGE FORMATION SYSTEM
E.

Controlling the Developing/Separation Static Eliminator Bias

1. Outline
The circuit shown in Figure 4-107 is used to control the voltage applied to the developing
assembly and the separation static eliminator, and has the following functions:
• Turning on and off the developing DC bias
• Turning on and off the AC bias (turning on and off the static eliminator bias)
• Controlling the voltage level of the developing DC bias
Both AC bias and DC bias are applied to the developing cylinder while copies are being made.
When the photosensitive drum rotates and yet developing is not under way, about -500 VDC is
applied to the developing cylinder regardless of the position of the density adjusting lever, thereby
preventing adhesion of excess toner on the photosensitive drum.
Reference:
Developing DC bias: -40 ~ -550V
Developing AC bias: 1350Vpp±100Vpp
4-12
COPYRIGHT © 1999 CANON INC. CANON NP6512/6612/7120/7130/7130F REV.0 AUG. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)