Canon LBP-1120 Service Manual page 86

CHAPTER 4
5. Dirt or foreign materials on the fixing unit entrance guide.
Action: Clean the fixing unit entrance guide.
6. Foreign materials on the fixing film unit.
Action: Replace the fixing film unit.
7. Defective developing cylinder.
Action: Replace the cartridge.
8. Dirty mirror in the laser/scanner unit.
Action: Replace the laser/scanner unit.
II-9. Black Horizontal Lines
<Possible Causes>
1. Horizontal scar(s) on the photosensitive drum.
Action: Replace the cartridge.
2. Dirty, deformed or worn fixing film.
Action: Replace the fixing film unit.
II-10. White Horizontal Lines
<Possible Causes>
1. Horizontal scar(s) on the photosensitive drum.
Action: Replace the cartridge.
2. Defective fixing film unit.
Action: Replace the fixing film unit.
II-11. Blank Spots
<Possible Causes>
1. Lack of toner.
Action: Remove the cartridge from the printer. Rock the cartridge in the manner described on V-B-c of
Chapter 1, and then install it back to the printer. If the problem still remains, replace the cartridge.
2. Dirty or deformed transfer charging roller.
Action: Replace the transfer charging roller.
3. Defective photosensitive drum or developing cylinder.
Action: Replace the cartridge.
II-12. Poor Fixing
<Possible Causes>
1. The nip width of the fixing unit is not within the specification.
Action: Replace the fixing pressure units.
4 - 10