Cleaning The Primary Charging Wire; Outline; Automatic Cleaning Mechanism - Canon NP6251 Service Manual

G. Cleaning the Primary Charging Wire

1. Outline

The machine is equipped with an automatic cleaning mechanism for the charging
wire of the primary charging assembly which is executed when the following conditions
are met:
• The surface temperature of the fixing roller at power-on is 100°C or less.
• The automatic cleaning mechanism is executed in user mode. (p. 1-17)
• Last rotation (LSTR) initiated every 2,000 copies ended. (If cleaning has been
executed under the foregoing two conditions, cleaning will be executed every 2,000
copies thereafter.)

2. Automatic Cleaning Mechanism

If the surface temperature of the fixing roller is 100°C or less at power-on, the primary
charging wire cleaner motor (M12) rotates clockwise to move the cleaner forward for
about 20 sec. The cleaner motor then rotates counterclockwise to move the cleaner in
reverse for about 16 sec. (The machine is not equipped with a position sensor.)
The RAM on the DC controller PCB keeps track of the cleaning operations so that
cleaning is executed every 2,000 copies. (In the case of continuous copying, cleaning
will be executed when as many copies as set have been made.)
Primary charging assembly
DC controller PCB
COPYRIGHT © 1997 CANON INC.
Feeding screw
Wire
Wire cleaner
Primary charging wire cleaning motor drive command
(PCLM) J103B-3.4
Figure 4-123
CANON NP6350/NP6251 REV. 0 JULY 1997 PRINTED IN JAPAN (IMPRIME AU JAPON)
CHAPTER 4 IMAGE FORMATION SYSTEM
Primary charging wire cleaning motor (M12)
4-25