Web lateral position control

Abstract From the Canadian patent

A method and apparatus for controlling the lateral position of a moving web of material having a central longitudinally extending web axis extending generally parallel to the direction of movement of the web so as to maintain the central longitudinally extending axis of the web at a substantial constant lateral position relative a fixed longitudinally extending axis associated with a fixed web alignment station based upon the detected longitudinal distance between certain portions of a series of longitudinally spaced apart substantially, identical, generally transversely extending indicia in a longitudinally extending indicia path parallel to the central longitudinal axis of the web.