Ricoh FT4460 Service Manual page 344

1.3 UNEVEN IMAGE DENSITY - 1
- Phenomena -
1. Uneven image density appears on solid black copies.
2. Areas where the image density is uneven do not move when the
reproduction ratio is changed.
- Possible Cause -
Uneven charge on the drum
(1) Dirty charge corona wires or grid
(2) Uneven height of charge corona wires
(3) Slack in the grid
Uneven image density with a solid black copy is usually caused by a dirty
transfer corona wire. Uneven image density with a halftone image is
usually caused by a dirty charge corona wire.
- Actions -
1.
Clean the charge corona wire and grid.
2. Check that the charge corona wire is not caught on the wire cleaner. If it
is not, adjust the wire height at the front. The standard height is 9 mm
from the grid.
NOTE: For fine adjustment, adjust the drum current with the drum shoe.
3. Check the tension of the grid tension spring.
12-7
28 February 1989