Dropouts, Horizontal Streak, Black Dots; Black Vertical Streaks - Kyocera Mita FS-6750 Service Manual

Troubleshooting
Print quality problems

Dropouts, horizontal streak, black dots

Note the spacing of the
defects. Refer to Repetitive
defects gauge.
Check paper property.
Check the transfer roller
installation.
Check the transfer bias
potential.

Black vertical streaks

Contaminated main charger
wire.
Check the drum surface for a
streak of toner laying length-
wise.
Defective magnet roller (in
the developer).
FS-6750
Check point
• If the defects occur at regular intervals of 39 mm, the
• If the defects occur at regular intervals of 126 mm, the
• If the defects occur at regular intervals of 79 mm (press
• Paper with rugged surface or dump tends to cause drop-
• The transfer roller must be supported by the bushes at
• Check the transfer bias output on the high voltage unit.
Check point
• Clean the main charger wire by pulling the green colored
• A streak of toner remaining on drum after printing
• Replace the developer.
Suggested remedy
problem may be the damaged developing roller (in the
developer). Replace the developer.
problem may be the damaged drum (in the drum unit).
Replace the drum unit.
roller) or 94 mm (heat roller), the problem may be the
damaged fuser unit. Replace the press roller or heat
roller.
outs. Replace paper with the one that satisfies the paper
specifications.
the both ends. Clean the bush to remove oil and debris.
Replace the transfer roller if necessary.
This requires removal of the left cover and the test equip-
ment. Replace the high voltage unit if high voltage poten-
tial is not available on the board.
Suggested remedy
cleaning knob in and out several times.
means that the cleaning blade (in the drum unit) is not
working properly. Replace the drum unit.
6-23