Web tracking system

摘要

A web tracking system for a continuous web of material which is transported from a supply to a takeup means along a predetermined path via one or more processing stations and comprises aligned tracking indica along at least one edge of the web. Means are provided to observe the tracking indica as the web is transported along the system path and produce information either indicative of dimensional changes in the length and width of the web due to web shrinkage or expansion or indicative of a particular point along the length of the web useful at one or more of the processing stations in the system.