CHAPTER 4 TROUBLESHOOTING IMAGE FAULTS/MALFUNCTIONS
4-17
3.12 The copy has a white spot (horizontal).
Exposure system
1) Generate a halftone test print in service mode. Enter ‘4’ to the follow-
ing: COPIER>PG>TYPE. Does the output image have a white spot?
NO:
Go to step 4.
Developing assembly
2) Does the problem occur at intervals of about 35 mm?
YES:
•
Clean the developing block members.
•
Dry wipe the surface of the developing cylinder.
•
If a scratch is found on the surface of the developing cylinder, re-
place the developing cylinder.
Drum unit
3) Does the problem occur at intervals of about 94 mm?
YES:
•
Clean the drum.
•
If a scratch is found on the drum, replace the drum unit.
Paper
4) Try paper fresh out of package.
YES: The paper may be moist. Advise the user on the correct method of
storing paper.
Transfer charging roller, Developing bias
5) Is there a white spot on the photosensitive drum during copying opera-
tion?
NO:
Check the transfer charging roller for leakage.
YES: Check the developing bias.
