Patent ID: 7681999

Claim:
An ink-jet printing head having a cavity unit, said cavity unit comprising: a plurality of nozzles for ejecting an ink; a plurality of pressure chambers communicating with the respective nozzles; a common manifold chamber for distributing the ink into the plurality of pressure chambers; and a flexible plate having said plurality of nozzles and including a wall portion which partly defines said common manifold chamber and which constitutes a damper portion, wherein said damper portion absorbs a pressure wave of the ink propagating from each selected one of said pressure chambers to said common manifold chamber, when the ink in said each selected pressure chamber is pressurized to eject the ink from the corresponding nozzle, and wherein said flexible plate comprises a gas-permeable resin material, and said wall portion which partly defines said common manifold chamber comprises a gas-impermeable film which prevents permeation of air into the common manifold chamber through the flexible plate.