User Guide

CHAPTER 11 TROUBLESHOOTING
COPYRIGHT © 1999 CANON INC. CANON NP6512/6612/7120/7130/7130F REV.0 AUG. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)
11-57
C. Troubleshooting Image Faults
1 The copy is too light. (halftone area only)
2 The copy is too light. (including solid area)
3 The copy is too light. (enter image, appreciably)
YES/NO
YES
NO
NO
YES
YES
NO
YES
NO
Cause
Lens, Reflect-
ing plate, AE
sensor, Static
eliminator
------------
Transfer
charging roller
Copy paper
Transfer lower
guide, Varis-
tor
Composite
power supply
PCB, DC
controller
PCB
Drum unit
Developing
bias, Develop-
ing bias
terminal
Step
1
2
3
4
5
6
Checks
Clean the lens, reflecting plate, AE sensor,
and static eliminator. Is the problem
corrected?
Turn off the power in the middle of a
copying run, and open the machine's top
unit. Is the toner image before transfer
more or less normal? (Be sure to make a
check in a short time to protect the drum
from light.)
Is the transfer charging roller normal?
Try fresh copy paper. Is the problem
corrected?
Measure the electrical resistance on the
transfer lower guide plate and the side
plate (metal) of the fixing assembly. Is it
0Ω?
Replace the drum unit. Is the problem
corrected?
Action
End.
Go to step 6.
1. Mount the transfer
charging roller
correctly.
2. Replace the transfer
charging roller.
1. The copy paper may
be moist. Instruct the
user on the correct
method of storage.
2. Inform the user that
using non-recom-
mended paper may
not bring the best
results.
1. Check to find out if
the transfer lower
guide happens to be in
contact with a metal
part (side plate).
2. Replace the varistor.
1. Check the transfer
high-voltage terminal
contacts for electrical
continuity.
2. Check the composite
power supply and the
DC controller PCB.
End.
Replace the electric unit
(composite power supply
PCB, DC controller
PCB).
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