Interval Possible cause Necessary actions
At intervals of 82 mm (3.23
inches)
Defective image transfer belt drive
roller or image transfer belt idling
roller
Replace the image transfer
belt drive roller or image
transfer belt idling roller.
Dark Vertical Line on Prints
Symptom Possible cause Necessary actions
A dark line appears. The line is
parallel to the paper feed
direction of one CMY color.
Defective PCDU Replace the PCDU.
A dark line appears. The line is
parallel to the paper feed
direction of any color (not C, M,
or Y).
Dust in the laser beam path Clean the laser beam path.
Defective image transfer belt
unit
Replace the image transfer belt
unit.
Defective fusing unit Replace the fusing unit.
White Horizontal Lines or Bands
Symptom Possible cause Necessary actions
White lines or bands appear in
images of all toner colors.
Defective PCDU Replace the PCDU.
Defective image transfer belt
unit
Replace the image transfer belt
unit.
Defective paper transfer roller Replace the paper transfer
roller.
6. Troubleshooting
620