Plate assembly suitable for ink-jet-type printing head

A plate assembly for an ink-jet-type printing head, comprising

• first and second plates having opposite surfaces of a predetermined shape, said first plate having a plurality of openings for passing ink therethrough as discharge nozzles for the ink, and said second plate defining at least part of a pressure chamber having a variable volume, which is in communication with said discharge nozzles and in which the ink can be pressurized;
• and
• an intermediate sheet having a shape which substantially corresponds to the shape of said surfaces of the first and second plates, said intermediate sheet being interposed between the first and second plates and bonding the first and second plates with each other, and having at least one opening which is aligned with said at least one opening in said first plate, said opening in said intermediate sheet being defined by a periphery which is substantially flush with a periphery of the corresponding opening in said first plate;
• said intermediate sheet comprising a thermoplastic resin which has been heated under pressure, the periphery of said at least one opening in said intermediate sheet, before the intermediate sheet is heated, being set-back from the periphery of the corresponding opening in said first plate, by a first set-back amount in a first direction connecting said openings in said first plate, and by a second set-back amount in a second direction which is different from said first direction, said second set-back amount being greater than said first set-back amount.