Canon GP160F Service Manual page 252

CHAPTER 13 TROUBLESHOOTING
1 Too Light
Cause Steps
Copy paper 1
2
3
Cartridge 4
Poor connector 5
connection
Cartridge 6
(primary charg-
ing roller)
Laser scanner 7
unit
DC controller
PCB
Transfer guide 8
Transfer charg- 9
ing roller con-
tact
Transfer charg-
ing roller
Dirty scanner 10
assembly
13-18
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Checks
When new (unopened) copy paper is
used, does the density become
darker?
Make a test print following the direc-
tions on page 13-120. Is the output
image too light?
Interrupt and stop the machine while
the image is being printed onto pho-
tosensitive drum. Is the toner being
developed on the drum surface?
Remove the cartridge. Does the
problem improve after the cartridge
has been lightly shaken 5 or 6
times?
Check the connection between con-
nector J304 on the DC controller
PCB and the laser scanner unit. Is it
normal?
Is the trouble resolved when the car-
tridge is replaced?
Is the trouble resolved when the
laser scanner unit is replaced?
When the transfer guide and other
metal parts are measured by a
tester, is the electrical resistance 0
ohms?
Check the transfer charging roller
and the high voltage contact point.
Are they dirty?
Does the image improve when the
mirror and lens dust proof glass are
cleaned?
COPYRIGHT © 1999 CANON INC.
Yes/No
YES 1. The paper may be
2. If paper other than
NO Check from Step 10.
YES Check from Step 8.
YES End
NO Connect firmly.
YES End
YES End
NO Replace the DC con-
troller PCB
NO Check that no screws
or other metal parts
have fallen near the
transfer guide.
YES Clean the contacts.
NO Replace the transfer
charging roller.
YES End
CANON GP160 REV.0 FEB. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)
Action
damp. Advise the
user on paper stor-
age methods.
the recommended
paper is being used,
explain to the user
that this may cause
an inferior image.