| 摘要 |
PURPOSE:To alway enable the stable detection of paper regardless of the deterioration of light emitting and receiving elements, by arranging a sensor consisting of light emitting and receiving elements in a conveyor route and comparing the signal obtained by integrating the output of the sensor and the signal corresponding to the output signal of the sensor. CONSTITUTION:A sensor 1 consisting of light emitting and receiving elements outputs the signal based on the light receiving element as V1 while this output V1 is outputted as an integration signal V2 through an integrating circuit 2. Further, the output V1 is divided to V3 by a voltage divider circuit 3. These outputs V2, V3 are compared by a comparator 4 and, if either one of them becomes higher, said outputs are reversed. That is, if paper is detected by the sensor 1, the voltage of V1 changes abruptly. Therefore, the voltage V3 similarly changes largely. On the other hand, the output V2 is the integration output signal of V1 and only gradually changes even if V1 changes abruptly. Further, even if the output V1 changes by the change in light emitting and receiving amounts caused by the contamination of the sensor, voltages V2, V3 also change and therefore, a wide range of comparison is performed and an object to be detected can be detected positively. |
