| 摘要 |
<p>PURPOSE: To obtain high reliability against a disturbance by making up a tracer, which detects the edge position of a web in a non-contacting manner, of a emitting unit and a receiving unit comprising a plurality of discharging and receiving elements respectively at the positions facing each other. CONSTITUTION: This tracer comprises an emitting unit 1 and a light receiving unit 3 retained by a U-shaped holder 9. The emitting unit 1 comprises a plurality of emitting elements 2 which are arranged in a row and can each be driven independently, emitting parallel light shown by broken lines. The light receiving unit 3 comprises a plurality of receiving elements which are similarly arranged in a row, receiving the parallel light from the emitting unit 1. When a web 4 is positioned between the units 1, 3 and a part of light from the emitting unit 1 is obstructed, an electronic amplifying device 7 converts the output signals of the receiving elements 5 into digital signals, which are inputted to a microcomputer 8. Based on the input signals, the edge position of the web 4 is detected.</p> |
