Symptom: Black spots at the leading edge
Check
Action if Yes
Action if No
Clean inside the machine, especially around the fusing unit and transfer unit entrances.
Clean the transfer corona wire and check that it is installed properly.
If the problem remains, change the transfer corona wire or the power pack.
Symptom: Horizontal white lines or stripes across printouts
Check
Action if Yes
Action if No
1. Make sure that the user is using the correct type of copy paper, and storing it in a dry
place.
2. Does the printout have a
crease mark where the
white band appears?
Check the paper feed
mechanism and path from
paper feed through transfer;
correct any faults.
Go to step 3.
3. Does the development
bias terminal stay at a
constant voltage
(about -530 Vdc)?
Go to step 6.
Go to step 4. Do not adjust
the variable resistors on the
power pack.
4. Does the FCU output the
power and bias trigger
signal to the power pack?
Clean the area around the
bias terminal. Go to step 5.
Change the FCU.
5. Does the problem go
away if you change the
power pack?
Finished.
Clean the development
roller. Go to step 6.
6. Clean the transfer corona unit (wire, endblocks, casing).
Check and replace any parts that may be causing the corona charge to leak.
7. Check that the development roller and master unit are both rotating smoothly, and that
the start and stop at the same time. If there are any problems, do the following:
a) Check the roller, master unit, and drive mechanism for any defective components,
such as gears.
b) Try changing the main motor.
Symptom: Black page with horizontal white stripes
Check
Action if Yes
Action if No
Replace the optic fiber cable from the main scan start detector.
If the problem remains, change the LD unit or FCU.
Symptom: Random black spots on the printout
Check
Action if Yes
Action if No
The grid plate may not be grounded properly. If the problem cannot be corrected, try
changing the charge corona unit, which contains the grid plate.
If the surface of the development roller is dirty, clean it.
The laser diode may be out of control. Change the LDDR or FCU.
Symptom: Horizontal black stripes
Check
Action if Yes
Action if No
1st August, 1994
TROUBLESHOOTING
COPY QUALITY TROUBLESHOOTING
6-8