Overlapped-sheet detection apparatus

摘要

An overlapped-sheet detection apparatus comprises a forwarding roller 4 rotating while making contact with sheets 1 to forward the sheets 1; a shifting roller 5 provided at a position where said shifting roller 5 and said forwarding roller 4 pinch at said sheets, said shifting roller 5 being configured to shift said sheets if said sheets are overlapped and to follow a rotation of said forwarding roller if said sheets are not overlapped; driving torque means 6 for supplying said shifting roller 5 with driving torque to shift said sheets; detection means for detecting rotation states of said shifting roller 5; and discrimination means 80 for judging from said rotation states detected by said detection means that said sheets are overlapped, wherein a friction coefficient µr1 between said forwarding roller 4 and the sheet, a friction coefficient µr2 between said shifting roller and the sheet 1 and a friction coefficient µp between the sheets 1 are satisfied with relationships of µr1 > µp and µr2 > µp, further comprising control means 100 for controlling said driving torque means 6 to transmit less driving torque than in ordinary cases when said discrimination means 80 judges that said sheets are overlapped.