| 摘要 |
PURPOSE:To detect the joint and end of sheet material without making a detection hole applying tape having reflection face onto a guide board and the joint of sheet material for a pair of photosensors to be used as detection element. CONSTITUTION:The photosensitive member 1 has low reflection factor to produce insufficient amount of light for the sensibility of photosensor 2 thereby the photosensors 2a, 2b will never detect the radiated light. Upon passage of a joint 4 through photosensors 2a, 2b, first photosensor 2a will first produce a detection signal then second photosensor 2b will produce a detection signal with slight time lag to decide the existence of joint 4 on the basis of said signals. Upon passage of the end of said member 1 through the photosensors 2a, 2b, reflected light from a guide board 3 is detected simultaneously by the photosensors 2a, 2b to produce detection signal thus to disable detection of the end of said member 1. In such a manner, the joint and the end can be detected without making a detection hole nor contacting the detection element against the sheet material. |
