Patent ID: 7267339
Filing Date: 2007-09-11
Classification: B65H

Abstract:
1. An overlapped-sheet detection apparatus comprising: a forwarding roller to forward sheets in a conveying direction along a conveying path; a shifting roller positioned adjacent to said forwarding roller to pinch said sheets between said shifting roller and said forwarding roller, said shifting roller 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 for supplying said shifting roller with a driving torque to shift said sheets; a first sensor disposed upstream of said forwarding roller to detect a rear edge portion of said sheets in the conveying direction; a second sensor disposed between said first sensor and said forwarding roller to detect said rear edge portion of said sheets in the conveying direction; and discrimination means for judging if said sheets are overlapped based upon a period of time between detection of said rear edge portion by said first sensor and detection of said rear edge portion by said second sensor.