| 摘要 |
PROBLEM TO BE SOLVED: To simplify the structure for sensing of a plurality of sheet detecting sensors S1-S6 arranged in a sheet carrying passage in an image forming device such as copying machine or the like, and also minimize the possibility of radio interference. SOLUTION: The photodiode PD of each sheet detecting sensor S1-S6 is driven with a modulation signal of different frequency by an oscillating circuit OS, and the frequency component in the signal is analyzed in a receiving circuit REC to judge the detection result of each sheet detecting sensor S1-S6. A sensor harness line is jointly used to reduce the sensor harness lines to be distributed to three of (+)- and (-)-power source lines L1 and L2 and a sensor output line L3. Accordingly, the distribution can be simplified to simplify the structure for sensing, and the possibility of radio interference can be also minimized. |
