Guide or contact roller for handling material web, in particular in a roll winding device

摘要

A material sensor (10) is provided on the contact roller (5). The sensor can be an optical sensor and produces a signal which as the roller rotates periodically changes at least in the event of a fault. When material (3) rests on the roller (5) the sensor produces a signal which is different from the second type of signal produced with a faulty material web.