The Copy Is Blank - Canon CLC 1120 Service Manual

Cause
ADJUST>HV-
SP>HV-SP
Toner (excess
amount)
14

The copy is blank.

Cause
-------------
Potential control
fault
Transfer charging
assembly
Developing
assembly (faulty
locking)
Developing
cylinder clutch
Transfer high-
voltage
COPYRIGHT © 1999 CANON INC.
Step
2 Increase the setting of SP-OFST in
ADJUST>HV-SP>SP-OFST in
service mode. Is the problem
corrected?
3 Check the latent image formation
system and the developing system.
Is there a fault?
Step
1 Generate a horizontal stripe test
print (TYPE=10). Is the image
normal?
2 Execute FUNCTION>DPC>DPC
in service mode. Is the copy image
after execution normal?
3 Is the transfer blade locking lever
of the transfer charging assembly in
the locked position?
4 Is the transfer charging assembly
securely fitted?
5 Is the developing assembly locked
to the photosensitive drum during
development?
6 Is the developing cylinder rotating
during development?
7 Open the front right cover during
development, and remove the
photosensitive drum unit. Is the
image on the photosensitive drum
normal?
CANON CLC1120/1130/1150 REV.0 MAR. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)
CHAPTER 13 TROUBLESHOOTING
Checks
Checks
Yes/No Action
YES End.
Settings: -6 to 0
Unit: 50 µA
YES Correct the fault.
NO Decrease the copy
density using the Copy
Density key.
Yes/No Action
YES Check the wiring of the
following PCBs; if
normal, try replacement:
· analog processor PCB
· IP-MAIN PCB
· CCD unit
YES End.
NO Set the lever to the
locked position.
NO Fit the charging
assembly.
NO See 43. "The developing
assembly fails to be
locked in position."
NO Check the developing
cylinder clutch.
YES · Check the transfer
high-voltage system.
· Check the high-
voltage cable from the
HVT PCB to the
transfer charging
assembly: if a fault is
found, replace the
high-voltage cable; if
normal, replace the
HVT-DC PCB.
NO · Check the developing
bias system.
· Try replacing the
developing bias PCB.
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