| 摘要 |
PURPOSE:To detect the edge of a beltlike sheet by a simple, inexpensive device by arranging fiber ends of optical fiber groups for projection and photodetection longitudinally at right angles to the run direction of a beltlike sheet. CONSTITUTION:The fiber ends of the optical fiber groups 3 and 4 for projection and photodetection are arranged opposite the beltlike sheet 1 which runs continuously from the same side. The fiber groups 3 and 4 are long enough to cover the operation range of the sheet 1. When the sheet 1 passes above the fiber groups 3 and 4 installed nearby, light emitted by a light source 5 for projection through the fiber group 3 is reflected where it is disturbed by the sheet 1, and then photodetected by the fiber group 4. There is no reflection where the light is not disturbed by the sheet 1, and the light is not photodetected by the fiber group 4. Thus, the obtained photodetection signal is led to a photodetector 6, which outputs an electric signal corresponding to the received photodetection signal, i.e. signal corresponding to the edge position.
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