Patent ID: 7372061

Claim:
A system for use in detecting the edge of a web of moving material, the system comprising; an optical source operative to transmit light; an optical receiver positioned to receive light transmitted by the optical source and operative to generate a first signal; an ultrasonic source operative to transmit sound; an ultrasonic receiver positioned to receive sound transmitted by the ultrasonic source and operative to generate a second signal; and a controller coupled with the optical source, the optical receiver, the ultrasonic source, and the ultrasonic receiver, the controller being operative to activate the optical source and the ultrasonic source and receive the first and second signals, the controller being further operative to select the optical source and receiver or the ultrasonic source and receiver for use in detecting the edge of a web of moving material based upon the first and second signals; wherein the optical source and the optical receiver are spatially separated and the ultrasonic source and the ultrasonic receiver are spatially separated such that a portion of a web can pass between the optical source and the optical receiver and between the ultrasonic source and the ultrasonic receiver.