Modeling of Web Tension Responses and its Application to Newspaper Printing

The paper discusses the web tension responses to changes in various press conditions through an analytic approach. The approach uses mathematical derivations to not only clear some ambiguous explanations for what have been experienced in the press room, but also to provide a practical means to relate and therefore predict web tension response to changes in several press parameters. While the application was of a special concern for newspaper press, one may find it applicable to other press operations. The derivations started with an ideal case in which the web slip was excluded, then proceeded to express how the web/roller interactions which caused web slip caused deviation of the tension prediction from the ideal case. Also discussed is the effect of tension level change on in-line cutoff registration, which provides a foundation for a low cost open-loop cutoff control system. A set of field test data was included to illustrate some of the conclusions drawn from the approach.