2-68
Confidential
All black
Dirt on back side of paper
<User Check>
• Clean the corona wire of the drum unit.
• Replace the drum unit with a new one.
Step Cause Remedy
1
Dirt on the electrodes of the
drum unit and those of the
machine
Clean the electrodes of the drum unit and
those of the machine. (Refer to Fig. 2-8 (P2-
42) and Fig. 2-9 (P2-42).)
2 Laser unit flat cable failure Replace the laser unit flat cable.
3
Dirt on the electrodes of the
high-voltage power supply
PCB and those of the
machine
Clean the electrodes of the high-voltage
power supply PCB and those of the machine.
4
High-voltage power supply
PCB failure
Replace the high-voltage power supply PCB
ASSY.
5 Laser unit failure Replace the laser unit.
6 Main PCB failure Replace the main PCB ASSY.
<User Check>
• This problem may disappear after printing multiple
sheets of paper.
• Replace the drum unit with a new one.
Step Cause Remedy
1 Dirt in the paper feed system Wipe dirt off.
2 Dirt on the fuser unit Replace the fuser unit.
3
High-voltage power supply
PCB failure
Replace the high-voltage power supply PCB
ASSY.