Man Roland Druckmaschinen Ag

Rudolf Annecke

Rainer Burger

To improve the uniformity of application of damping liquid, typically water, to a plate cylinder (8) of an offset rotary printing machine, a non-contacting, typically spray damper (18) sprays or otherwise applies damping liquid on a damping liquid accepting cylinder (19) with a hard, preferably chrome-plated surface. The damping liquid is applied to the plate cylinder by an application cylinder or roller (21) having a soft, for example rubber or textile surface. A transfer cylinder (20) transfers the water between the accepting roller (19) and the application roller (21). In accordance with the invention, the transfer roller (20) has a soft, for example rubber surface. The soft or rubber surface apparently causes formation of an ink-damping liquid emulsion on the surface thereof which is extremely fine grain to provide a highly uniform coating of damping liquid to the application roller (21). To improve the fineness of damping liquid distribution, more than one (201, 202) such transfer cylinders may be used, each having a soft, typically rubbery surface. Without such soft, rubbery surface transfer cylinders, the minimum number of rollers, for example three (19, 20, 21) would not be possible while still providing a uniform film of damping liquid to the plate cylinder.

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Augsburg, Germany

Rudolf Annecke