Man Roland Druckmaschinen Ag

Maschinenfabrik Augsburg-nurnberg Aktiengesellschaft

Herbert Stockl

Johann Winterholler

Albert Engl

Eduard Hoffmann

Wolfgang Prem

Peter Meinke

Josef Plantsch

Siegfried Gunther

Albert Stegmuller

A circumferentially continuous printing plate, which has the advantage over clamp plates that a clamping arrangement and groove in a plate cylinder can be eliminated, is formed by rolling a flat printing plate into tubular or sleeve form and welding the end edges together, preferably by a neodymium-YAG laser weld, resulting in a narrow, less than 1 mm wide, weld seam (2) having upper and lower concave sides, or by adhering the end edges to an underlay saddle (9), the plate can be coated and imaged when flat or after having been rolled and installed on a plate cylinder (37) of a printing machine. Interengaging projection-and-recess elements (4, 6; 14, 16) are formed on the plate (1, 1') and on the cylinder (37), respectively, to ensure lateral and circumferential register.

Welded tubular printing plate, and the method of making

To permit computer control, for example from a control console in a publisher's office, of the subject matter to be printed from a printing cylinder, the printing cylinder (3) has a layer of semiconductor material thereon, which, by doping, includes capacitative or inductive domains (15, 33), selectively energized in accordance with control from the computer through controllable electronic switches (16, 29), such as transistors formed in the semiconductor layer. Ferrofluidic ink can be attracted by charges onto capacitors formed in the semiconductor layer; the capacitors are charged, selectively, through the transistor electronic switches which are located and connected in a matrix. Packing densities of over 160 domains and switching elements per mm.sup.2 are readily possible and suitable, for example, for newspaper printing. Higher packing densities, for high quality printing, can be obtained by well known microelectronic technology. Further, depolarized regions are hydrophobic, and permit acceptance of printing ink, whereas polarized domains are hydrophilic, attract water, thereby permitting use of well known lithographic-type offset printing.

Electrically controllable printing form for a printing machine

To prevent entirely, or at least largely, loss of contact of a pair of blanket cylinders as they roll off against each other upon passing the respective clamping grooves of the rubber blanket cylinders, the rubber blanket cylinders adjacent the edges of the clamping groove (13,14) are formed with transition zones (15,17; 16,18) which rise above a circle formed by the cylinders, in cross section. The rise (Y) is in accordance with a non-circular mathematical function, and, for a cylinder of, for example, about 20 cm diameter, can be in the order of 0.1 mm. At operating speeds of current rotary offset printing machines, the rubber blankets will hardly lose contact from each other and thus stripping formation, due to oscillations of the blanket cylinders as they roll off against each other, is effectively eliminated.

Rubber blanket cylinder for a rotary offset printing machine

To permit adjustment of the engagement pressure of mutually engaged roller elements, such as bearer rings (1, 3) or rubber blanket cylinders (31-34) against an impression cylinder or plate cylinders (35-38), a blind bore (4) is formed in the respective roller elements in a zone where engagement pressure will result in deformation in a wall of the blind bore, the bore being filled with a fluid such as hydraulic fluid, silicone, or the like, the pressure of which is determined by a pressure transducer such as a piezoelectric element coupled, through an amplifier, to a peak detector which indicates pressure upon axial alignment of the blind bore (4) and the axes of rotation of the respective engaging rollers. A base pressure in the chamber can be adjusted by an outside adjustment screw which, like the transducer, is preferably carried on an external adapter element attached to the respective roller.

Engagement pressure measuring apparatus for rollers in printing machines

To provide for automatic threading of a paper web throughout an entire printing press equipped with a press threading mechanism, and also over the folding former thereof, two paper guide baffles are located at the back side of the folding former extending in converging direction from the edges of the former to the tip thereof and up to the nip between a pair of take-up rollers located below, and adjacent the tip of the former. Air pressure differential generating means, typically air blast nozzles are directed towards the guide baffles to generate an under pressure adjacent to surfaces thereof which will pull paper downwardly into the nip between the take-up rollers. The take-up rollers themselves have a knurled, or ribbed surface and are driven by air blasts directed against the ribbing of the surface, to move paper which is guided over the folding former by the air blasts away and through the former mechanism. Thus, threading of the press can be done entirely automatically, eliminating the requirement of a pressman, threading the paper web over the former.

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Augsburg, Germany

Herbert Stockl