Canon GP405 Service Manual page 465

13 The back of the copy is soiled.
Cause
Exposure system
Transfer guide
assembly
Transfer guide
bias
Transfer guide
Magunet plate
Developing
assembly,
Registration roller
Drum cleaner
Transfer charging
roller
Fixing assembly
COPYRIGHT © 1999 CANON INC. CANON 405/335 REV.0 JAN. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)
Step Check
1 Turn off the main power switch
while paper is moving through the
feeding assembly. Is the back of the
paper soiled at this time?
2 Replace the drum causing the
problem (e.g., black lines). Is the
back soiled?
3 Is the voltage between the transfer
guide (+) and the machine side
plate (-) about -100 to -400 V?
4 Is the problem noted at intervals of
about 50 mm?
5 Execute roller cleaning in user
mode. Is the problem corrected?
6 Are the take-up mechanism of the
fixing cleaning belt and the
cleaning mechanism of the upper
roller normal?
CHAPTER 14 TROUBLESHOOTING
Yes/No
NO Go to step 5.
YES Clean the transfer guide
and the magnet plate.
NO • Check the transfer
guide bias connector.
• Clean the magnet
plate.
• Clean the transfer
guide.
YES • Clean the transfer
guide.
• Check the developing
assembly for leakage
of toner.
• Clean the magnet
plate.
• Clean the bottom of
the developing
assembly.
NO • Clean the feeding
assembly.
• Clean the transfer
guide.
• Clean the magnet
plate.
• Check the drum
cleaner assembly for
leakage of toner.
YES End.
NO • Check the cleaning
belt take-up
mechanism.
• Clean the fixing
roller.
• Clean the fixing
assembly inlet guide.
YES • Replace the transfer
charging roller.
Action
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