Ricoh FT4460, Service Manual, Page: 114 / 413

28 February 1989
9.2 FRR FEED SYSTEM
9.2.1 Pick-up Roller
The pick-up roller [A] is in contact with the paper stack before it starts feeding
paper. A few moments after the Start key has been pressed, the rotation of
the pick-up roller feeds the top sheet to the feed [B] and separation [C]
rollers. At almost the same time as the paper’s leading edge arrives at the
feed roller, the pick-up roller lifts off the paper stack so that it does not inter-
fere with the operation of the feed and separation rollers. The feed and
separation rollers then take over the paper feed process.
9.2.2 Feed and Separation Rollers
There is a one-way bearing inside the feed roller [B] so it can turn only in one
direction. The separation roller [C], however, is driven through a slip clutch,
which allows it to turn in either direction depending on the friction between the
rollers. A spring keeps the separation roller in contact with the feed roller.
The direction that the separation roller [C] turns depends on the frictional for-
ces acting on it. The slip clutch applies a constant clockwise force (F1). When
there is a single sheet of paper being driven between the rollers, the force of
friction between the feed roller [B] and the paper (F2) is greater than (F1). So,
the separation roller turns counterclockwise.
If two or more sheets are fed between the rollers, the forward force on the
second sheet (F3) becomes less than (F1) because the coefficient of friction
between the two sheets is small. So, the separation roller starts turning clock-
wise and drives the second sheet back to the cassette.
2-61