Canon NP6621 Service Handbook page 59

13 The back of the copy is soiled.
Cause Step
1 Turn OFF the power switch while copy
paper is moving through the feeding
assembly. Is the back of the copy
soiled at this time?
Transfer 2 Execute service mode No. 403
charging (transfer roller cleaning). Is the prob-
roller lem corrected?
3 Make several blank copies. Is the
problem corrected?
4 Is the transfer charging roller exces-
sively soiled?
Drum 5 Is the soiling on the back horizontal at
cartridge intervals of about 4.2 cm?
6 Is the soiling vertical at intervals of
about 1.6 cm?
Drum clean-
ing assembly
(drum
cartridge)
Fixing 7 Is the upper fixing roller or the lower
assembly fixing roller dirty?
Checks
IMAGE FAULTS
Yes/No Remedy
NO Go to step 7.
YES End.
YES End.
YES Replace the transfer charg-
ing roller.
YES 1. Clean the registration
roller and the transfer
guide plate.
2. Check the drum cartridge
for leakage of toner.
YES 1. Clean the manual feed
feeding roller.
2. Check the drum cartridge
for leakage of toner.
NO 1. Clean the feeding assem-
bly.
2. Check the drum cartridge
for leakage of toner.
YES 1. Clean the upper and
lower fixing pressure
roller.
2. Check if the oiling roller is
soiled with toner, if the
roller is very dirty, replace
it.
NO Clean the delivery roller and
the fixing assembly paper
guide plate.
3–13