| 摘要 |
PROBLEM TO BE SOLVED: To obtain a measuring method for width and/or meandering quantity of a long body capable of exactly and continuously measuring in line regardless of the surface state of magnetic tape. SOLUTION: A light casting part 1 and a light receiving part 2 are provided at both ends of a sensor base 16, a magnetic tape 14 is made to run in a direction crossing between the two and the width and the meandering quantity in the width direction of the magnetic tape 14 are measured based on the shading quantity by the magnetic tape 14 of laser light L emitted from the light casting part 1. In this method, when light is cast at least on the end of the width direction against the long body running in the length direction and the outside near-by region, received with a light reception means and the width and/or meandering quantity in the width direction of the long body from the output of the light reception means, the cast light is scanned along the width direction of the long body and the scan direction is varied according to the running velocity of the long body and so the shift of measuring position due to running of the long body is avoided and the position of the end part in the width direction of the long body together with the shield light quantity can be exactly detected.
|
