Canon NP6621, Руководство по обслуживанию

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3–7
IMAGE FAULTS
4 The copy has uneven density (darker at front).
5 The copy has uneven density (lighter at front).
Cause
Scanner
Primary
charging
roller
Transfer
charging
assembly
Pre-expo-
sure lamp
Developing
assembly
Step
1
2
3
4
5
6
7
8
Checks
Clean the scanning lamp, reflecting
plate, side reflecting plate, mirror,
lens, and dust-proofing glass. Is the
problem corrected?
Execute service mode 402 (primary
charging roller cleaning). Is the
problem corrected?
Execute service mode 403 (transfer
roller cleaning). Is the problem cor-
rected?
Make several blank copies. Is the
problem corrected?
Is the transfer charging roller installed
securely?
Are the position and the condition of
the transfer charging roller pressure
spring normal?
Does the pre-exposure lamp remain
ON during copying operation?
Is the developing cylinder coated with
a uniform layer of toner?
Yes/No
YES
YES
YES
YES
NO
NO
NO
NO
Remedy
End.
End.
End.
End.
Install the charging roller
securely.
Correct or replace the spring.
See “The pre-exposure lamp
fails to turn ON.”
Take out the developing
assembly, shake it several
times, and make copies. If
the Problem is not corrected,
replace the developing
assembly.