Canon LBP-1760, Service Manual

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2. Dirty, deformed or worn fixing film unit
Action: Replace the fixing film unit.
I-9. Dirt
<Possible causes>
1. Dirty paper
Action: Replace the paper. Advise the customer on how to store paper.
2. Periodic dirt (cassette separation roller, feed roller, pre-transfer roller, fixing film unit, EP-52
cartridge)
Action: Identify and clean the dirty part according to Table 4-2-1 on page 4-??. If dirt can-
not be removed, replace the dirty parts.
I-10. Blank spots
<Possible causes>
1. Dirty or deformed transfer charging roller
Action: Replace the transfer charging roller.
2. Poor contact between the engine controller PCB toner sensor contact and toner cartridge
contact
Action: Clean the contact(s) if dirty. If the problem still remains after cleaning, or the con-
tact(s) is/are deformed or damaged, replace the contact(s).
3. Defective photosensitive drum, developing cylinder, or toner sensor
Action: Replace the cartridge.
4. Defective engine controller PCB
Action: Replace the engine controller PCB.
I-11. White vertical lines
<Possible causes>
1. Circumferential scars on the photosensitive drum
Action: Replace the cartridge.
2. Defective developing cylinder
Action: Replace the cartridge.
3. Foreign materials are deposited on the laser outlet of the printer or the laser inlet of the car-
tridge.
Action: Remove the foreign materials.
4. Dirt or foreign materials on the fixing unit entrance guide.
Action: Clean the fixing unit entrance guide.
5. Scars or foreign materials on the fixing film unit surface.
Action: Replace the fixing film unit.
6. Dirty mirror in the laser/scanner unit.
4 - 13
CHAPTER 4