Canon CLC 1120 Service Manual page 632

Cause
------------
Toner
concentration
sensor
DC driver PCB,
CPU PCB
Stray light
Black toner
concentration
sensor
Photosensitive
drum
DC driver PCB,
CPU PCB
COPYRIGHT © 1999 CANON INC.
Step Checks
5 Is E020 indicated for Bk? (Is it
E020=04xx?)
6 Replace the toner concentration
sensor of the color for which E020
is indicated. Is the problem
corrected?
7 Is the copier's front cover left open
after the transfer unit front cover is
removed (i.e., is the black toner
concentration sensor subjected to
stray light)?
8 Replace the photosensitive drum. Is
the problem corrected?
CANON CLC1120/1130/1150 REV.0 MAR. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)
CHAPTER 13 TROUBLESHOOTING
Yes/No
YES Go to step 7.
YES End.
· When you have
replaced the toner
concentration sensor,
be sure to replace the
developer also.
NO Replace the DC driver
PCB or the CPU PCB.
YES Mount the transfer unit
front cover.
NO Replace the black toner
concentration sensor.
· If you have replaced
the toner concentration
sensor, be sure to
replace the developer
also.
YES End.
NO Replace the DC driver
PCB or the CPU PCB.
Action
13-105