Edge scan sensor for web guiding apparatus

摘要

A sensor system for determining the position of an edge of a moving web of material travelling along a predetermined travel path. the sensor system comprising a transmitter/receiver assembly, a beam reflector assembly and sensor signal processing. The transmitter/receiver assembly is positioned adjacent to the travel path of the moving web of material. The transmitter/receiver assembly has a transmitter transmitting a light curtain across at least a portion of the travel path, and a receiver receiving a shifted light curtain transmitted across at least a portion of the travel path and generating video output signals indicative of the position of the edge of the moving web of material. The beam reflector assembly is also positioned adjacent to the travel path of the moving web of material such that the travel path passes between the transmitter/receiver assembly and the beam reflector assembly. The beam reflector assembly receives an unblocked portion of the light curtain, shifts the unblocked portion of the light curtain a distance laterally to form the shifted light curtain, and transmits the shifted light curtain across the travel path of the moving web of material.