Ricoh FT7770 Service Manual page 535

Uneven Density
1) Image density gradually
changes across the copy.
Darker area has dirty
background.
Does the darker area follow the image when
copies?
Clean the charge corona wires. Are the charge corona wires
incorrectly positioned in the wire cleaner and end block?
Y N
Is the charge corona current uneven across the drum?
Y
Readjust the charge corona current and wire height.
Position the wires correctly.
Are any of the optics parts stained?
o Toner Shield Glass
o Exposure Glass
o Mirrors, Lens, Reflectors
N
I
Are any of the exposure lamps stained black?
Y N
Does the uneven area match any of the lamp positions?
N
Correct uneven exposure using the adjustment plates.
Note: The position of the adjusting plates is very
Replace the exposure
Clean them.
N
Clean the transfer corona unit.
critical. Mark the original position before
moving the plates.
lamp unit.
making reduced
13-11
30 April, '89