Web tracking system
AssigneeXerox Corporation
InventorsRobert P. St. John, William A. Lloyd
Life of this patent
Estimating the term…
Abstract
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.
Claims14
Web tracking system for a continuous web of material which is transported from a supply roll means to a takeup roll means along a predetermined path via one or more sequentially positioned processing stations to treat said web comprising
- aligned tracking indicia comprising a line of registration marks of substantially uniform spacing and width along each edge of said web,
- means mounted relative to the passage of said web to optically observe said tracking indicia along each of said web edges as said web is transported along said path and produce informational tracking signals based upon the passage of said tracking indicia relative to said observation means,
- circuit means responsive to said informational signals to produce control signals indicative of changes in the lateral and longitudinal dimensions of said web,
- means to provide relative translation between said processing stations and said web along said path,
- said translation means responsive to said control signals to translate said processing stations according to changes in the lateral and longitudinal dimensions of said web.
Web tracking system for a continuous web of material which is transported from a supply roll means to a takeup roll means along a predetermined path via one or more sequentially positioned processing stations to treat said web comprising
- aligned tracking indicia along at least one edge of said web,
- said tracking indicia comprising a plurality of aligned of registration marks of substantially uniform spacing and width and a plurality of aligned initializing marks preceding said registration marks and having a different geometric shape compared to said registration marks,
- means mounted relative to the passage of said web to optically observe said tracking indicia as said web is transported along said path and produce an informational signal indicative of distant lengths along said medium useful at one or more of said processing stations,
- circuit means responsive to said informational signal indicative of the recognition of said initalizing marks and determinative of the point of transition from the last of said initializing marks to the first of said registration marks, said circuit means further determinative of the distance between said transition point and a predetermined point further along said registration marks wherein the treatment of said web is desired to be initiated relative to any one of said stations.
Dependencies are inferred from the claim text.