Primary Charging Roller Cleaning Control - Canon NP6412 Service Manual

D.

Primary Charging Roller Cleaning Control

1. Outline
The machine is equipped with an automatic cleaning mechanism used to remove toner and
paper lint sticking to the primary charging roller.
2. Operations
The primary charging roller is cleaned by turning on the primary charging roller cleaning sole-
noid (SL6), thereby forcing the cleaning pad against the roller.
The cleaning pad is forced against the roller for about 1.5 sec. While the roller is being cleaned,
all other high-voltage outputs are turned off except the developing DC bias (cleaning bias).
Cleaning is executed for the following three independent conditions:
• Condition 1
During last rotation after making 10 copies (cumulative).
For this condition, cleaning is executed only once between when the power is turned on and
when it is turned off. The number of copies made after these ten will be stored in memory by the
DC controller PCB and added to the number of copies made after the power is turned on next time.
• Condition 2
During last rotation after making 20 copies (cumulative).
For this condition, there is no limit to the number of times cleaning is executed, and the cumu-
lative number is cleared when the power is turned off and then on.
• Condition 3
When user mode 'U1' has been executed.
COPYRIGHT © 1999 CANON INC. CANON NP6512/6612/7120/7130/7130F REV.0 AUG. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)
CHAPTER 4 IMAGE FORMATION SYSTEM
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