Man Roland Druckmaschinen Ag

Gerhard Hackelborger

Werner Sondergeld

An improved surface casing for a sheet-guiding printing cylinder comprising a number of elevations having constant cross-sectional areas extending radially therefrom to form a sheet bearing surface. The constant cross-sectional area over the length of the elevations ensures that as the elevations are worn down over time, the overall bearing area does not increase. As a result, smearing of the printing image, which is related to the total bearing area, does not increase over time. Additionally, the total bearing area does not increase for sheets having a low paper weight due to sagging of the sheet between the elevations.

Sheet-guiding impression-cylinder casing profile

A damping roller for the damping unit in a printing press has a roller body that carries a glass, glass ceramic, or enamel outer material, layer, or coating. Suitable coatings can be produced, for example, by enamelling, plasma spraying, or attaching the outer layer to the body with a sealing compound. In another embodiment, the glass, glass ceramic, or enamel material acts as the self-supporting roller member accommodated solely by the journals. Preferably, the outer surface of the roller is polished. The damping roller of the invention has the ability to dispense an optimum amount of damping medium while eliminating or reducing damping medium additives such as alcohol to less than 6% of the total mixture.

Damping roller for a printing press

A process for the production of a surface structure on a printing cylinder for offset printing presses, wherein said cylinder includes a galvanically coated hard chrome surface, comprising applying a thin layer of alkali-resistant negative-resist material to said hard chrome surface, contacting the resist material with a positive raster, irradiating said cylinder to harden a portion of the resist material, removing the unirradiated resist material, and etching said hard chrome surface by forming a circuit with said printing cylinder as the anode, contacting said hard chrome surface with a sodium hydroxide solution which has passed through a cathode, and removing the hardened resist material from said printing cylinder.

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Offenbach am Main, Germany

Gerhard Hackelborger