Suction film holder

Abstract

A suction film holder preferably for a reproduction camera and comprising a plate with channels opening outwards and communicating with a suction means. The known suction holders comprise a plurality of concentric chambers mutually communicating through valves, only the intermediary chamber being connected to the suction source. The sheet in question may therefore neither be of an arbitrary size nor be arbitrarily located. According to the invention the channels uniformly dispersed across the entire plate are individually connected to the suction means through at least one valve, said valve closing when a heavy flow takes place and slightly opening when substantially the same pressure is present on both sides thereof. In this manner the sheet may have an arbitrary size and be arbitrarily located. A plurality of channels always open on to the back of the sheet, the valves of said channels slightly opening when substantially the same pressure is present on both sides of the valve, i.e. a low pressure retaining the sheet. The valves located in the channels opening on outside the sheet close.

Dependencies are inferred from the claim text.