Patent ID: 7677711

Claim:
An ink-feeding device for ink-jet printing apparatus, comprising: an ink-containing tank ( 2 ); at least one print head ( 7 ) connected to the tank ( 2 ), wherein it further comprises a metering device ( 3 ) interposed between the tank ( 2 ) and the print head ( 7 ) and having an inner space ( 10 ) with a prevailingly planar extension and a varying volume which is adapted to keep the pressure of the ink feeding the print head ( 7 ) substantially constant; wherein the metering device ( 3 ) comprises an upper wall ( 11 a ) consisting of a flexible membrane ( 12 ) and a lower wall ( 11 b ) consisting of a flexible membrane ( 12 ), said walls ( 11 a , 11 b ) delimiting the inner space ( 10 ), each flexible membrane ( 12 ), in a non-deformed position, lying in a plane; wherein each of the flexible membranes ( 12 ) is deformable out of the respective plane between a first configuration, in which said walls ( 11 a , 11 b ) are at a maximum mutual distance from each other and the varying volume is maximum, and a second configuration, in which said walls ( 11 a , 11 b ) are at a minimum mutual distance from each other and the varying volume is minimum; wherein the metering device ( 3 ) further comprises a box-shaped case ( 20 ), said case ( 20 ) being provided with an inner chamber ( 21 ) inside which said flexible membranes ( 12 ) are housed; wherein said flexible membranes ( 12 ) are fastened to the case ( 20 ) by their edges ( 12 a ).