Primary Charging Roller Cleaning Control - Canon NP6621 Service Manual

K. Primary Charging Roller
Cleaning Control
1. Outline
The machine's primary charging roller is
equipped with an automatic cleaning mechanism.
The automatic cleaning mechanism cleans the
primary charging roller under the following
conditions:
• During initial rotation (INTR) after making 250
or more copies (accumulative; i.e., after
executing transfer roller locking/releasing
control five times).
Primary charging roller
cleaning solenoid
COPYRIGHT © 1998 CANON INC.
Fulcrum
Drum unit
Figure 3-318
CANON NP6621 REV.0 FEB. 1998 PRINTED IN JAPAN (IMPRIME AU JAPON)
OPERATIONS AND TIMING
2. Primary Charging Roller Cleaning
Operations
The microprocessor (Q301) on the DC controller
PCB generates the primary charging roller cleaning
solenoid (SL4) ON signal (PCLSLD), thereby forcing
the cleaning pad against the roller for 2 sec. (During
this period, the cleaning roller rotates about four
times.)
Fulcrum
Cleaning pad
Drum
Primary charging roller
3–55