| 摘要 |
A system for controlling the path of a web of material (18), which is transported from a supply (20) to a takeup means (32) along a predetermined path via one or more processing stations (12, 14, 16), comprises aligned tracking indicia (72, 74, 78) along at least one edge of the web. Means are provided to observe the tracking indicia as the web is transported along the system path and produce signals representing 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. |
