Ricoh FT7770 Service Manual page 65

2. Side Erase and Leading/Trailng Eage Erase
,
- Side Erase -
Side erase discharges the drum potential on both sides of the image area. It
overlaps the image slightly on either side as shown in the figure. This
prevents the edge of the original from being copied.
The CPU calculates the side erase margins from the paper size and "the se-
lected magnification ratio.
- Leading and Trailing Edge Erase -
The entire bank of erase lamps turns on to erase the drum before and after
the image area.
slightly. The leading edge margin helps to prevent fusing jams by making it
easier for the stripper pawls to separate the paper from the hot roller.
Trailing edge erase turns on about 2 mm before the trailing edge of the im-
age area or trailing edge of the paper, whichever
Leading edge erase overlaps the paper and the image
is
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30 April, '89
smaller.