Abstract: A damping roller for printing presses and a method for the production thereof, wherein a heat injected microporous special steel coating is applied to a cylindrical base body, is described. The average pore body of said coating is approximately 5 &mgr;m. A thicker moistening agent film is obtained by capillary force thereby enabling a higher moistening agent flow rate in the damping system of an off-set printing press.

Abstract: A method and apparatus for cleaning a printing cylinder surface in a printing machine of strongly adhering dirt, such as paper dust and hardened printing ink. This is achieved by applying a predetermined coating of alkaline cleaning agent to the printing cylinder surface by a cleaning roller and allowing the cleaning agent to act on the surface for a defined time, preferably greater than sixty minutes, and then subsequently removing the cleaning agent from the printing cylinder surface by means of a cleaning fluid, such as water.

Abstract: A printing material guiding surface structure, preferably for cylinders or cylinder dressings of printing machines has a surface structure which facilitates improved sheet guiding in that the friction forces at the contact points of the printing material and the surface structure are increased. This is achieved by utilizing elevated structure elements which are arranged on a substrate, and which have a bearing surface with a multiplicity of depressions that increase the surface roughness thereof and have good ink repelling characteristics.

Abstract: The present invention relates to a process for producing a surface structure, preferably on a cylinder, cylinder dressing, or roller of a printing machine, with a hard chromium coating which is galvanically produced and preferably ground to dimensional accuracy. The object of the invention is to develop a process which permits a surface structure to be produced on the hard chromium coating, which surface structure permits relatively high frictional forces between the contact points of the printing material and the coating of the cylinder of the printing machine. This is achieved in that the surface structure is produced in two process steps in sequence, a surface part structure being produced as a dot screen in an approximately even random distribution by means of a first material erosion process in a first process step, and the final surface structure being produced in a second process step by means of a second material erosion including the dot screen.

Abstract: 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.

Abstract: 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.

Abstract: To obviate local differences in heat expansion in the ink duct, ink metering means and ductor roller, and to temper the printing ink, stabilize the ink-damping agent emulsion and protect the ductor roller from corrosion, the ink duct includes a heat insulating material secured to underside of the duct body and a mid-section portion of the duct body side facing the ductor roller is supplied with a warm air flow from the printing press, boosted by a plurality of fans.

Abstract: A gripper finger for a sheet gripper system for a printing press, to which gripper unwanted paper dust, dirt, debris, or the like cannot stick, the profiled retaining surface of the finger has in its front part a single bead-like protuberance which contacts the sheet, has a bead radius (R) of from 0.4 to 1.0 mm, extends parallel to the front edge of the sheet and is coated with a hard substance.

Abstract: The invention relates to a process for the production of structured retaining areas on sheet grippers, sheet gripper supports or similar gripper facilities for machines for handling and processing sheets by the formation of a non-etchable dot structure on the base member and the subsequent etching out of intervening areas. To provide structured retaining areas having a smoothly shaped surface, the dot structure is produced by screen printing or pressure pad printing and after the etching-out of unprinted areas, a hard smoothing coating, preferably of chromium or ceramic, is applied to the structural retaining area.