| 摘要 |
PURPOSE:To convey a web while making it always travel a steady position by oppositely providing an ultrasonic transmitter and an ultrasonic receiver across the edge part of a traveling web, and measuring the quantities at which ultrasonic waves are interrupt by said web which passes in between and detecting the edge of side webs. CONSTITUTION:An ultrasonic transmitter 3 and an ultrasonic receiver 4 are provided across the edge part of a traveling web 1 to continuously measure quantities at which ultrasonic waves are interrupted by the web 1, and a control device 5 and a power unit 6 are operated to correct the travel of the web 1 to be always in a steady position. Therefore, it does not occur that the web is stained deteriorating its quality nor that traveling stability is impaired as in the case of using air. Also, unlike the case of using a visible light, even with the web 1 which is liable to be previous to the visible light like a transparent web, the edge of the web 1 can be detected, enabling the web 1 to be adjusted to always travel a steady position.
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