| 摘要 |
PCT No. PCT/DE90/00888 Sec. 371 Date Apr. 30, 1992 Sec. 102(e) Date Apr. 30, 1992 PCT Filed Nov. 17, 1990 PCT Pub. No. WO91/07842 PCT Pub. Date May 30, 1991.The invention is directed to a device for clamping sheet-shaped film material onto the recording drum of a reproduction device and is directed to the operation of this device. The recording drum comprises axially proceeding suction-hole rows for the vacuum-fixing of the recording material. Suction channels, each of which connects the suction holes of a suction hole row to one another, proceed in the wall of the recording drum. A vacuum distributor controllable by the rotational movement of the recording drum is arranged in the recording drum, this controllable vacuum distributor selectively bringing the individual suction channels, the corresponding suction hole rows into communication with a stationary vacuum pump. The vacuum distributor is controllable such that that suction hole row on which the starting region of the recording material lies is first charged with vacuum during the clamping event. As a result thereof, a high initial vacuum is achieved, as a result whereof the recording material does not slip. Further suction hole rows are then successively cut-in in accordance with the increasing wrap of the rotating recording drum by the recording material and are charged with vacuum. The cut-in of further suction hole rows is ended in accordance with the respective circumferential length of the recording material at that suction hole row on which the end region of the recording material lies. In particular, large-format recording material can be clamped onto the recording drum without creating folds and warping, and can be reliably fixed thereat with the device.
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