Ricoh FT4430 Service Manual page 87

April '88
16
FRICTION PAD FEED SYSTEM
This copier uses a feed roller and friction pad paper feed system. The friction
pad separates a single sheet from the top of the stack of paper.
When the feed roller [A] starts turning, it forces a single sheet of paper across
the friction pad [B]. The roller stops turning when the paper reaches the
registration rollers.
At that time the friction pad is pressing the paper up against the feed roller.
So, when the registration rollers start turning, the friction of the moving paper
as it is pulled from under the feed roller causes the feed roller to start turning
again. As the trailing edge clears the leading edge of the paper stack, the
feed roller catches on the next sheet and starts moving it forward. The feed
roller stops turning when the trailing edge of the first sheet leaves the feed
roller. The leading edge of the next sheet is then held ready for feeding
between the friction pad and feed roller.
Sometimes sheets of paper tend to stick together (perhaps due to static
electricity or poorly cut edges). When this happens, two sheets may feed
between the feed roller and friction pad. However, the coefficient of friction
between the friction pad and lower sheet is much greater than that between
the two sheets of paper; so, the top sheet slips through while the pad holds
the lower sheet.
The friction pad holder is mounted on one end of the swivel plate with a swivel
screw; so, it automatically applies even pressure against the feed roller and
the copy paper. The pad pressure spring on the other end of the swivel plate
(reverse side) provides the pressure. After removing the cassette, the pad
pressure is released.
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