Heidelberger Druckmaschinen Ag

Peter Melzer

Volker Haushahn

Stefan Schmidt

Gerhard Fritz Blöhdorn

Heinz Gerhard Franke

Andr&eacute; Wirtz

A method for setting up and/or operating a web-fed printing press includes winding a material web onto a roller, printing a portion of the material web, then unwinding and removing an unprinted part of the material web located before from the roller, and then fixing a cut start of the printed material web to the take-up roller. During the method, the material web is first conveyed backward for the unprinted part to be cut off, then a drive of the material web is switched to a holding mode, in which the material web stands still while maintaining web tension, the material web is drawn from a web start in direction of the take-up roller with little tensile force and the web start is fixed to the take-up roller. A web-fed printing press for carrying out the method is also provided.

Method for setting up and/or operating a web-fed printing press and web-fed printing press for carrying out the method

Measuring a feed spindle length change in a printing exposer, having at least one exposure head on a carrier moved axially along the drum in a feed direction by a stepping motor and the spindle, carries out the measurement by determining the number of stepping motor cycles needed by the carrier to travel through a reference section parallel to the feed direction. During calibration, an optimum number of cycles per revolution of the exposure drum is set, and the number of cycles needed to travel through the reference section is determined. During an operating phase, the number of cycles needed to travel through the reference section is determined and a corrected number of cycles per revolution of the exposure drum is determined in accordance with the relationship K=K&#xd7;M/M. The temperature of the components involved in the measurement is kept constant with a temperature control system.

Apparatus and method for measuring the length change of the feed spindle in an exposer for printing originals

A device and a method detect an edge of a recording material, in particular a printing plate, in an exposer for recording printing originals. An exposer has an exposure drum for holding the printing plate, and an exposure head, which is moved axially along the exposure drum and focuses exposure beams onto the printing plate. The position of the edge of the printing plate is determined by a sensing device. To this end, a sensing finger is pivoted into a groove in the surface of the exposure drum and a signal is generated by a sensor when the sensing finger moves when it touches the edge of the recording material. The sensor used is preferably a microswitch. The axial position of the edge of the printing plate is determined by counting the cycles of the feed drive that moves the sensing device.

Device and method for detecting the edge of a recording material

A method and an apparatus for measuring linearity in a reproduction appliance includes an operating carriage bearing a scanning or recording device. The operating carriage is able to be moved in discrete steps in a given direction along a straight line. The operating carriage is successively moved along partial segments of the line. Each of the partial segments is longer than a travel corresponding to one of the steps and is shorter than the entire length of the line. The partial segments each have an exactly defined length defined by an additional carriage moveable along the given direction. The number of steps needed for each partial segment are counted and deviations between values for a travel of the operating carriage resulting from the partial segment and values for the travel of the operating carriage resulting from counting the steps are calculated.

Method and apparatus for linearity measurement

A drive system for a carriage, which is fitted with a scanning or recording device, in a reproduction appliance, in which the scanning or recording device scans or exposes a recording material periodically along scanning or recording lines. The carriage is moved forward with the aid of a drive apparatus along a straight line at right angles to the scanning or recording lines. The drive apparatus contains an electric motor whose rotation speed is determined by a frequency of drive pulses that are produced by dividing a master clock by an integer factor. The drive apparatus contains an apparatus for converting a rotary movement of the electric motor into a linear movement of the carriage. Furthermore, the drive system contains a device by which an identical number of drive pulses can be lengthened or shortened by one or more periods of the master clock in each scanning or recording period.

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Kiel, Germany

Peter Melzer