Heidelberger Druckmaschinen Ag

Hans-Jurgen Beck

Arno Wirz

Wolfgang Pfizenmaier

Gabriele Nowara

Apparatus for controlling the wetting behavior of the surface of a cylinder formed of passivatable metal. A wetting device is used to apply an electrolyte to the surface of the metal cylinder. A direct current source is connected between the wetting device and the cylinder and a control device is used to control the voltage necessary for passivating the surface of the cylinder as a function of the pH value of the electrolyte and the type of metal forming the surface of the cylinder. The oleophilic or oleophobic characteristics of the cylinder are thus controlled.

Device for controlling wetting behavior of metal surfaces by application

A metal foil made by electroforming from a master pattern with the interposition of a negative form, and serving as packing for sheet guiding cylinders and/or drums of rotary printing machines, including a substantially planar member having one flat face and an opposite face with a textured surface structure corresponding to an upper side of the master pattern, the upper side of the master patten having been roughened by a jet treatment and coated with a levelling galvano-layer in order to eliminate undercuts, the master pattern per se, and method of manufacture.

Metal foil electroformed with a master pattern, the master pattern per

A printing unit cylinder of a given diameter for offset rotary printing machines having a galvanically applied wear and corrosion-resistant jacket surface coating, comprising a cylinder body formed with a cylinder channel and having a transitional surface from a cylindrical jacket surface thereof to the cylinder channel, the cylindrical jacket surface and the transitional surface having a sand-blasted surface roughness of 10 to 20 microns, a nickel undercoating having a hardness of 180 to 220 Vickers hardness disposed on the cylindrical jacket surface and the transitional surface; and a chromium layer disposed on the undercoating and having a hardness of greater than 900 Vickers hardness and a microcracked surface of greater than 400 cracks per cm.sup.2, the cylinder body having a diameter less than the given diameter of the printing unit cylinder by a thickness corresponding to the superimposed thicknesses of the nickel chromium and the chromium layer.

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Heidelberg, Germany

Hans-Jurgen Beck