Printing Couple Dynamics of the Six-Page Wide Newspaper Press.

Several unique dynamics problems were encountered in the development of the six-page wide two-page around letterpress for the New York News. Primarily printing cylinder vibrations induced by the plate lockup and page margin discontinuities had to be kept to within amplitudes presently experienced in four-page wide letterpresses if acceptable print quality was to be obtained over the operating speed range of the new press. This paper describes the analysis of printing couple dynamics that led to the solution of this problem. A mathematical model of the cylinders was developed and programmed for an EA1 third-generation hybrid computer. Various plate lockup circumferential stagger angles were evaluated with the model to determine their effects on the cylinder vibrations. The best angular arrangement was tried on a full-scale prototype printing unit, and the resulting performance was found to be equivalent to that of four-page wide units and superior to that of six-page wide units with conventional lockup staggers. In the paper, the theoretical results are discussed and the derivation of a performance index for choosing the best configuration is described. Insight gained from the study of this problem is applied to the general case of high speed letterpress dynamics. In the paper, the theoretical results are discussed and the derivation of a performance index for choosing the best configuration is described. Insight gained from the study of this problem is applied to the general case of high speed letterpress dynamics.