Importance

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Abstract

Within the impression cylinder of a rotogravure press and within the roll shell thereof there are provided over the width of the impression cylinder a number of layer packages which can be separately supplied with electrical charge in order to apply electrostatic charges to the impression cylinder surface for the purpose of augmenting printing of a material web. By differently controlling segments of the impression cylinder, there can be accommodated different widths of the material web to be processed. In order to concentrate the electric charge at the actually used region of the impression cylinder and for protecting the zones of the impression cylinder which are not currently being used, there are provided internally of the roll jacket, in axial direction thereof, a number of support elements arranged adjacent one another and braced against a central carrier. These support elements are controlled such that only the support elements in those segments, where there is also supplied electrical charge, exert a pressing force. At the end regions of the impression cylinder, there can be provided counter support elements which are only controlled when there is not applied any electrostatic charge at the end regions of the impression cylinder, in other words, when printing a narrower material web. Hence, in this situation no electrical charge is transferred at the not used roll end regions and the impression cylinder is protected against wear and abrasion.

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First Claim