Surface structure for the drum of a recording device

摘要

A recorder contains a rotatably mounted drum which is structured as a vacuum or negative pressure-hollow cylinder. At the cylindrical circumferential surface of the drum body there is arranged at least one clamping or supporting region for the retention of a sheet-shaped record carrier or medium, each clamping or supporting region containing a closed channel system. Each individual channel system comprises a number of channels of a first group of channels which are arranged in the lengthwise axial direction of the drum and essentially parallel to a clamping portion and a number of channels of a second group of channels arranged essentially transversely with respect to the first group of channels. In order to obtain a stable smooth contact or support of the record carrier or medium at the drum there is provided in the last channel of the related clamping or supporting region, which is arranged parallel to the clamping portion, an opening which penetrates through the drum body. For the smooth contact of the marginal zone of the record carrier there is provided parallel to the last channel a further channel containing branch channels arranged transversely thereto as well as openings.