| 摘要 |
PURPOSE:To prevent the generation of a picture formation miss by detecting whether an original has been completely set or not and controlling the opening/ closing driving of an original press contacting member. CONSTITUTION:Detecting signals from respective photosensors are shaped at their waveform by respective Schmitt trigger circuits 12-17. Three signals outputted from the Schmitt trigger circuits 12-14 and three signals obtained by inverting outputs from the Schmitt trigger circuits 15-17 by NOT circuits 18- 20 are inputted to an AND circuit 21 to find out the AND. On the other hand, the signals outputted from the six Schmitt trigger circuits 12-17 are inputted to an AND circuit 22 as they are to find out the AND. Since the output signals of the AND circuits 21, 22 are inputted to an OR circuit 23, the output of the OR circuit 23 is ON only when the photosensors 6, 7, 10 are ON and the photosensors 8, 9, 11 are OFF or when all the photosensors 6-11 are ON, and in the OFF state in other cases. |
