| 摘要 |
PURPOSE:To measure the width of a strip with high precision by controlling the position of a photodetector by a servomechanism in such a way that the photodetector follows up both side ends of a strip. CONSTITUTION:Light from a light source 1 placed under a strip 10 which runs at right angles to a paper surface is detected by a detector 2. The positions of the photodetecting elements 6-1 and 6-2 of the detector 2 are controlled by a servomechanism 4 so that the light from the light source 1 is intercepted by the side end of the strip 10 and enters only one photodetecting element 6-2. This position is detected by a sliding resistor 3 in the form of a voltage to measure the side end position. At both the side edges of the strip 10, similar detectors are provided to measure the width of the strip 10 from both detected voltages. |
