Ricoh FT5034 Service Manual page 118

2. Dirty Background
Problem
When copying, dirty
background will appear
at manual image
density level 4.
When copying
newspaper, dirty
background will appear
at manual image
density level 7.
1. The charge corona wire is dirty
If the charge corona wire is contaminated, the charge on the drum
surface is increased due to a thicker diameter of the wire.
2. Dirty mirrors and toner shield glass
If the mirrors and shield glass are contaminated, the image pattern will
change when the reproduction ratio is shifted.
(1) The toner shield glass is dirty due to excess image density or
toner scattered when the inlet seal is deformed.
(2) The mirror and exposure glass are contaminated by oil.
3. Toner concentration is too high.
If toner concentration is too high, toner will be scattered inside the
copier, causing contamination of the toner shield glass, PTL ID sensor,
and transfer charge wire.
4. Seals are stripped off the development unit.
If seals are stripped off, toner will be scattered.
5. Intensity of exposure is too weak.
Deterioration of the exposure lamp or low lamp regulator output
voltage causes dirty background.
6. The doctor gap is too wide.
If the doctor gap is too wide, dirty background appear. Also, when
making solid black copies, carrier will be transferred to the drum (DG:
0.76 ± 0.1 mm).
7. Deterioration of the drum.
8. In ADS modes, V
DE
- 117 -
Cause
is too high.