| 摘要 |
A multiple sheet detecting apparatus is disclosed which includes an ultrasonic transducer responsive to a time varying electrical signal to produce a time varying ultrasonic signal which impinges upon sheet(s) at a position along a predetermined path. A second ultrasonic transducer receives a portion of the ultrasonic wave which passes through such impinged upon sheet(s) for producing a second time varying signal. Comparison means are then provided which compare the phase relationship between the time varying electrical signals and produce an indication when such phase relationship indicates a multiple sheet feed condition has occurred. |
