Ricoh FT4460, Service Manual, Page: 352 / 413

28 February 1989
1.11 HORIZONTAL BLACK LINES
- Phenomenon -
Black lines perpendicular to the paper feed
direction appear on the copy image.
- Possible Causes -
1.
2.
3 .
4.
Drum is scratched.
Hot roller is scratched.
Blade presses so hard that toner sticks to the drum surface.
For cause 1, 2 and 3, measure the distance between the horizontal black
lines.
If black lines appear at 251 mm intervals, the cause is a scratched drum
or toner build up. If the black lines are at 125 mm intervals, the cause is a
scratched hot roller.
If there are no scratches on the drum surface :
(1) Due to insufficient cleaning, a sticky foreign substance may be
attached to the blade, causing toner to attach to the drum suface
when the drum stops.
Things to look for:
The black lines appear at the same location on copies from different
single copy runs, regardless of the feed station that is used.
Black lines appear regardless of color mode, paper size, or
magnification ratio.
Black lines do not appear in APS mode.
(2) When the trailing edge of the paper is separated from the drum
surface, a charge is transterred to the drum surface. The charged
area is redeveloped in the cleaning unit and appears as a horizontal
black line on the copy.
Things to look for:
•
•
Black lines appear beginning with the second copy in multicopy
mode.
Black lines appear in a fixed location, regardless of paper size.
Black lines appear
magnification ratio.
regardless of color mode, paper size, or
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