IV - 4
Possible cause
Step
Check
Result
Remedy
Poor contrast
1
Is the contrast adjustment dial in
the center of click position?
No
Set it to the center click
position or reasonable
position.
Toner sensing
failure (toner
cartridge side)
2
Is the problem solved when 4 or 5 pages
are printed after the cartridge is replaced
with a full one?
Yes
The wiper of the toner
cartridge is defective.
Replace the toner cartridge.
Toner sensing
failure
(printer side)
3
Can printing be started with the drum unit
removed?
Yes
Toner sensor failure.
Check if the toner sensor
needs cleaning and check
the toner sensor connection.
Drum GND
connection failure
4
Is the drum shaft grounded when the drum unit is
installed?
No
Clean contact electrodes
between the printer body and
the drum shaft of drum unit .
Transfer electrode
contact failure
5
Is there continuity between the transfer roller shaft
and the transfer electrode on the external drum
unit?
Yes
Replace the drum unit.
Transfer failure
6
Is the problem solved when the transfer roller is
replaced?
Yes
Replace the drum unit.
Developing bias
contact failure
7
Are the developing bias contacts between
the printer body and the drum unit soiled?
Clean the terminals of both sides.
Yes
High-voltage
power supply
failure
8
Remove the main cover and measure the
voltage at the electrode plate at the right side
face while printing with the interlocks defeated.
Is the voltage correct?
No
Check the harness connection
between the high-voltage
power supply and the driver PCB.
If the connection is normal,
replace the high-voltage power
supply PCB.
Driver PCB
failure
9
Perform the same check as step 8 above.
No
Replace the driver PCB.
Light
I-1
2.2
Troubleshooting Image Defect
Procedures to follow in response to specific image defects.
