Influence of Roll Bending on Impression Pressure Distribution.

The problems of uniformity of impression pressure distribution across the width of the press assume greater significance as wider printing presses are planned or built. The effects of the bending of the printing couple forming cylinders on press runnability and print quality are difficult to evaluate by direct engineering calculations before a press is actually built and put into operation. In this paper a dimensionless pressure distribution index is derived from the stiffness of the cylinders, the resilience of the rubber covering or blanket and the width of the press. This index combined with the results of the GRI studies of the mechanics of the gravure nip allows extrapolations of the results obtained on narrow presses to new, wider press designs.