Heidelberger Druckmaschinen Ag

Klaus Olawsky

Rudi Junghans

Peter Hachmann

Norbert Thunker

A method prints on a printing material using inks and dampening fluids. An ink printing machine uses ink print heads to apply an image to a front side of the printing material and a dampening fluid print head to apply a dampening fluid image, thus reducing or avoiding water-related cockling of the printing material. The method includes: providing the image to be printed, calculating n different color separation matrices, calculating n ink amount matrices Afrom the color separation matrices, and calculating a total ink amount matrix A. For every element of the total ink amount matrix: calculating a matrix B as B=G*A, with a weighting matrix G and determining the maximum of the matrix B, calculating a dampening fluid matrix C, calculating the dampening fluid image from the dampening fluid image matrix C, and printing the ink image and the dampening fluid image.

Method for printing on absorbent printing material using inks and dampening fluids

A method for dampening a printing form for offset printing wherein a quantity of dampener applied to the printing form by transfer rollers is controlled by adjusting the rpm of one of the transfer rollers in accordance with the rotary angle position of a channel or gap of a form cylinder carrying the printing form includes periodically varying the rpm of at least one of the transfer rollers during each revolution of the form cylinder.

Method for dampening a printing form for offset printing

An inking unit for a printing machine, including an ink duct with a scoop cylinder partly dipping into ink received in the ink duct, further includes zonally acting metering elements for setting on a provided cylinder selected from a group thereof consisting of the scoop cylinder and another cylinder, an ink distribution corresponding to a printing image, the metering elements being individually convertible between two metering states, at least one transfer cylinder for transferring ink, which has been set on the provided cylinder by the metering elements, onto a printing form, a drive for rotating the scoop cylinder and further cylinders, and a control device connected to the drive and the metering elements, the metering elements being arranged above the level of the ink in the ink duct, so that two ink layer thicknesses differing from one another are producible in circumferential direction, over the width of a metering element, by the metering elements, respectively, in the two metering states, on the provided cylinder assigned thereto, the transfer cylinder being disposed in parallel with the provided cylinder to which the metering elements are assigned, the provided cylinder and the transfer cylinder having a clearance therebetween which is larger than a minimum ink layer thickness producible by the metering elements and smaller than a maximum ink layer thickness producible by the metering elements.

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Weinheim, Germany

Klaus Olawsky