Edge scan sensor for web guiding apparatus

A web guiding apparatus for guiding a moving web of material travelling along a predetermined travel path, the web of material having a first side, an opposed second side and at least one edge, the web guiding apparatus comprising:

• a sensor system, comprising:
• a transmitter/receiver assembly positionable adjacent to the travel path of the moving web of material, the transmitter/receiver assembly comprising:
• 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;
• a beam reflector assembly positionable 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 receiving an unblocked portion of the light curtain, shifting the unblocked portion of the light curtain a distance laterally to form the shifted light curtain, and transmitting the shifted light curtain across the travel path of the moving web of material;
• and
• a sensor signal processing receiving the video output signals and processing the video output signals to determine the location of the edge of the web of material, the sensor signal processing outputting signals indicative of the location of the edge of the web of material;
• and
• a web guiding assembly receiving error signals based on the signals output by the sensor signal processing for guiding the web of material.