| 摘要 |
PURPOSE:To detect a double feed of paper, by driving a light emitting element to generate a pulse, sensing its pulse state light with a light receiving element and converting the light into a pulse state optical current further detecting a pulse width corresponding to a level of this optical current during the passing of a paper sheet. CONSTITUTION:A transistor 22 is provided in the earth side of a light emitting diode 12 and turned on and off by a square wave oscillator 16 to emit pulse state light, then this light is sensed by a photodiode, converted into a pulse state optical current, amplified and output as a voltage signal. Then a device is constituted such that a signal output from a comparator 26 is formed to a pulse width in porportion to a pulse of the optical current and the signal is detected during the passing of a paper sheet to detect the paper sheet if double feed or not. In this way, a distance between the both diodes can be increased capable of flowing a large current and facilitating design and manufacture work of an equipment. |
