The Copy Has White Spots (Vertical); The Copy Has White Lines (Vertical) - Canon NP6251 Service Manual

CHAPTER 11 TROUBLESHOOTING

10. The copy has white spots (vertical).

11. The copy has white lines (vertical).

Cause Step
Fixing assembly 1
Primary 2
charging
assembly
Developing 3
assembly
Copy paper 4
Photosensitive 5
drum
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COPYRIGHT © 1997 CANON INC.
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Checks
Press the Copy Start key while
keeping the copyboard cover
open, and turn off the power
switch while copy paper is moving
through the feeding assembly. At
this time, does the copy image
before moving through the fixing
assembly have white spots or
white lines?
Clean the charging wire, grid wire,
and shielding plate of the primary
charging assembly. Is the problem
corrected?
Is the developing cylinder coated
with an even layer of toner?
Use fresh copy paper. Is the
problem corrected?
Are there scratches on the surface
of the photosensitive drum
corresponding to the problem in
the copy image in the peripheral
direction?
CANON NP6350/NP6251 REV. 0 JULY 1997 PRINTED IN JAPAN (IMPRIME AU JAPON)
YES/NO Action
NO 1. Clean the inlet (upper,
lower) of the fixing
assembly.
2. Check the upper roller
of the fixing assembly.
3. Check the take-up
mechanism (cleaning)
for the web.
4. Clean the separation
claw.
YES Clean the parts
thoroughly with alcohol.
If the dirt cannot be
removed, replace the
charging wire.
NO Check the blade edge of
the developing assembly
for paper lint.
YES The copy paper may be
moist. Advise the user
on the correct method of
storing paper.
YES Be sure to find out the
cause of the scratches,
and then replace the
photosensitive drum.
Cont'd