Man Roland Druckmaschinen Ag

Albert Engl

Peter Meinke

Herbert Stockl

Ingo K/o/ Bler

Hatto Hechler

Lutz Mauer

Herbert Stockel

Herbert St/o/ Ckl

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 suppress shocks from being transferred to the walls of a cylinder (3) of a printing machine, when grooves (7) on the cylinder roll-off against another cylinder, and particularly against the edges of another groove (8) in an engaging cylinder, a damping mass (11) is filled within the cylinder which additionally retains an elastic shaft (12) on which an inertia mass (13) is secured. The inertia mass, preferably in form of a ball, is excentrally located on the elastic shaft (12) and touches at a point C the inner surface of the wall (10) of the cylinder (3) when the cylinder is in engagement with another one. The impact or shock, at the edge of the groove (7) rolls off against an engagement cylinder causes the inertia mass (13) to be accelerated towards the center of the cylinder, typically upwardly, and to place this mass into oscillations. These oscillations are damped by the damping mass (11) thus preventing transfer of oscillatory bending movement to the wall of the cylinder, and hence to a covering ( 5) thereon, which, for example, may be a printing rubber blanket, a printing plate, or the like.

Shock and oscillation reducing apparatus for printing machine cylinders

To suppress shocks and bending oscillations arising upon roll-off of grooves (7, 8) of printing or blanket cylinders (3, 4) the blanket cylinders are constructed as hollow elements within which an absorber rod (12) is located, secured by a transversely extending member (11). The absorber rod which has propeller-like vanes, buckets or extensions (8) secured to its ends, the transversely extending member, and if provided, inertia masses secured to the end portions of the absorber rod are all embedded within a damping material filling the interior of the cylinder. The damping masses can be formed with the radial projections, vanes, buckets or propeller-like extensions (18), all embedded within the damping mass.

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Warngau, Germany

Albert Engl