Anordning för fasthållning av tryckplåtar vid exponering

摘要

The flat bed or drum (19) has vacuum-connected perforations (12) and a sheet tensioned over the bed or drum, particularly a rubber sheet (13) provided with perforations (17) corresponding to those of bed or drum and on the outside are arranged vacuum channels (18) between at least specific special series of perforation holes. - The arranged is so formed that one and the same rubber sheet can be used for several different formats on printing plates intended for copying retained against the rubber sheet. Suction holes (12) in the flat bed or drum are formed with a valve which is normally closed but which can be activated for opening when the printing plate or film is laid out on the rubber sheet.