The Copy Has White Spots (Horizontal) - Canon NP6251 Service Manual

CHAPTER 11 TROUBLESHOOTING

12. The copy has white spots (horizontal).

Cause Step
Developing 1
assembly
Drum 2
Copy paper 3
Scanner rail, 4
Scanner cable
Charging wire, 5
Photosensitive
drum
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Checks
Is the problem noted at intervals
of about 52 mm?
Is the problem noted at intervals
of about 25 cm?
Try fresh copy paper. Is the
problem corrected?
Does the problem occur at the
same location on all copies?
Are there scratches on the surface
of the photosensitive drum?
CANON NP6350/NP6251 REV. 0 JULY 1997 PRINTED IN JAPAN (IMPRIME AU JAPON)
YES/NO Action
YES 1. Clean the developing
rolls.
2. Dry wipe the surface
of the developing
cylinder.
3. If the surface of the
developing cylinder
have scratches,
replace the
developing cylinder.
YES 1. Clean the drum.
2. If scratches are found,
replace the drum.
YES The copy paper may be
moist. Advise the user
on the correct method of
sorting paper.
YES 1. Check the scanner rail
for foreign matter.
2. Adjust the scanner
cable.
NO Clean the charging
assembly.
YES Replace the
photosensitive drum.