II-8. Black horizontal lines
<Possible causes>
1. Horizontal scar(s) on photosensitive drum
Action: Replace the cartridge.
2. The upper fixing roller is dirty, deformed, or worn.
Action: Replace the upper fixing roller.
II-9. Dirt
<Possible causes>
1. The print paper is dirty.
Action: Replace with new paper. Advise the customer how to store print paper.
2. Periodical stain (separation roller, transfer charging roller, upper fixing roller, EP-72 car-
tridge)
Action: Referring to Table 4-2-1 on page 4-11, identify the dirty roller(s) and clean the dirty
areas. If the dirt cannot be removed, replace the dirty roller(s).
3. Dirty delivery roller
Action: Clean the delivery roller.
II-10. Blank spots
<Possible causes>
1. Lack of toner
Action: Remove the cartridge from the printer. Rock the cartridge in the way described in
the chapter 1, and then install it back in the printer. If the problem persists, replace
the cartridge.
2. The transfer charging roller is dirty or deformed.
Action: Replace the transfer charging roller.
3. Defective photosensitive drum or developing cylinder
Action: Replace the cartridge.
II-11. White vertical lines
<Possible causes>
1. Lack of toner
Action: Remove the cartridge from the printer. Rock the cartridge in the way described in
the chapter 1, and then install it back in the printer. If the problem persists, replace
the cartridge.
2. Circumferential scars on the photosensitive drum
Action: Replace the cartridge.
3. Defective developing cylinder
Action: Replace the cartridge.
4. Foreign materials are on the laser outlet of the printer or the laser inlet of the cartridge.
4 - 11
CHAPTER 4