JPH0585460B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field This invention relates to a friction separation paper feeding device used in copying machines and the like.

PRIOR ART A paper feeding device for a copying machine, a printing machine, a facsimile machine, etc., as shown in FIG. A feed roller 2, which is located downstream in the paper feeding direction and rotates in the same direction in synchronization with the pick up roller 1, is in pressure contact with this across the paper path, and a torque limiter applies a constant torque in the opposite direction to the paper feeding direction. It has a separate roller 3 which is given with A friction separation paper feeding device is known in which when sheets are fed double between the feed roller 2 and the separate roller 3, the paper is separated and only the one sheet in contact with the feed roller 2 is fed.

Compared to a separate paper feeder in which the separate roller always rotates in the opposite direction to the paper feeding direction, this type of paper feeder prevents the separate roller from slipping against the feed roller and the paper, and the paper does not slip due to friction with the rollers. It is superior in that it causes less fuzz, less paper dust, and less roller wear.

The principles of paper separation and paper feeding in this type of apparatus will be briefly explained.

When only one sheet of paper is sent by the pick-up roller 1 to the contact area between the feed roller 2 and the separate roller 3 as shown in FIG. 2, the feed force F _C that sends the sheet in the paper feeding direction is F _C =μ _R

Claims (1)

[Claims] 1. A feed roller that rotates in the paper feeding direction, and a separate roller that pinches the paper path and comes into pressure contact with the feed roller, and is given a torque in the direction opposite to the paper feeding direction by a torque limiter during paper feeding. Therefore, the limiting torque of the torque limiter is smaller than the torque determined by the frictional force between the feed roller and the paper conveyed between the feed roller and the separate roller, and the paper is fed double between the feed roller and the separate roller. In a friction separation paper feeding device that is set to have a torque greater than the torque determined by the frictional force between sheets of paper, the torque limiter is a core member of the separate roller, and both ends are fixed to the machine frame. a cylindrical member that is fitted into and rotatably supported by the separate roller shaft; a pair of disc-shaped torque plates; a pressure spring that presses each of the pair of disc-shaped torque plates against the end face of the cylindrical member; and a return spring whose other end is locked to a fixed point on the machine frame, and which is elastically deformed by the rotation of the torque plate in the paper feeding direction and generates a force to rotate the torque plate in the counter-paper feeding direction. A limit torque is determined by the frictional force between the torque plate and the end surface of the cylindrical member, and the cylindrical member of the torque plate is controlled by the pressure spring so that the limit torque becomes the above-mentioned required value. A friction separation paper feeding device characterized by setting a pressure contact force against an end face. 2. The paper feeding device according to claim 1, wherein the separate roller and the torque limiter constitute a unit, and the unit is easily attached to and removed from a paper feeding cassette.