Heidelberger Druckmaschinen Ag

Helmut Lange

Axel Gebhardt

Axel Heuer

Bernd Lassen

In an apparatus for point-by-point and line-by-line, opto-electronic scanning of masters chucked on a scanner drum, an illumination unit is provided for generating an illumination spot on the master. A scanner objective, a scanner element and a feed support is provided at which the illumination unit, the scanner objective and the scanner element are arranged. The illumination unit comprises a light conductor that is aligned in the direction of the rotational axis of the scanner drum and has a light exit face for generating a light spot and has optical elements for imaging the light spot onto the master as an illumination spot. At least a sub-section of the light conductor in the region of the light exit face can be inclined by small angles relative to the rotational axis with a Cardanic bearing for fine adjustment of optical beam paths, as a result whereof the illumination spot is displaced on the scanner drum. The slope of the light conductor that has been found to be optimum is then fixed.

Apparatus for scanning masters

In a method and apparatus for point-by-point and line-by-line scanning of masters chucked on a scanner drum, for pixel-by-pixel illumination of the master, a light spot is generated with a light conductor, the light spot being imaged by a matching objective onto the master as an illumination spot. The scan light is focused with a scanner objective and is converted into an image signal in an opto-electronic scanner element. The illumination spot, scanner objective, and scanner element implement a feed motion in the direction of the rotational axis of the scanner drum for planar scanning of the master. Given employment of scanner drums having different diameters, the size of the illumination spot is corrected by a modification of the imaging scale of the light spot. The modification of the imaging scale occurs by displacing the light conductor with an actuating drive relative to the stationary matching objective. A corresponding focus correction occurs with a radial displacement of the scanner objective.

Method and arrangement for scanning masters

In a device for point-by-point and line-by-line scanning of masters chucked on scanner drums having different diameters with an optoelectronic scanner element, which converts the scan light modulated with the content of the master and focused with the scanner objective into an image signal, a scanner element comprising a reflected light illumination is provided for generating an illumination spot on an opaque original. The scanner objective for correction of the focusing of the scan light onto the scanner element given employment of scanner drums having different diameters&mdash;is seated displaceable on the optical axis of the scanner element into radial working positions determined by the diameter of the respective scanner drums. The reflected light illumination can be displaced in the direction of the optical axis by the focal intercept change of the scanner objective for the purpose of optimizing the illumination spot given employment of scanner drums of different sizes.

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Schönkirchen, Germany

Helmut Lange