Mechanism for preventing the feeding of more than one sheet of paper at one time

Claim 1

A mechanism for preventing the feeding of more than one sheet of paper at one time comprising a document feeder having a pair of parallel shafts, one of which is a paper-supply roller shaft supporting a plurality of paper-supply rollers, and the other of which is a separation roller shaft supporting a plurality of separation rollers, wherein the distance between the shafts is slightly less than the sum of the radii of said paper-supply rollers and said separation rollers, and said paper-supply rollers and said separation rollers are arranged in a zigzag manner, an outer peripheral surface of each of said paper-supply rollers serially having a large frictional section producing much friction between the paper-supply roller and the paper and a small frictional section producing little friction between the paper-supply roller and the paper, said small frictional section of said paper-supply roller is made of an adapter, which has a roller-compensating part including a roller-compensating section functioning as one part of the outside of the paper-supply roller and a supporting section for supporting said roller-compensating part that is to be put on the roller shaft so as to be straddled by the paper-supply roller in the direction of the width of the paper-supply roller.