Abstract: There is disclosed an ink jet printhead assembly which has a plurality of structures laminated together, one of the structures being a printhead with a plurality of nozzles and one or more heater elements in a bubble forming chamber corresponding to each nozzle. Each heater element is configured to heat a bubble forming liquid in the printhead to a temperature above its boiling point to form a gas bubble therein. The generation of the bubble causes the ejection of a drop of an ejectable liquid through an ejection aperture in each nozzle, to effect printing. The remaining structures including a plurality of passages for the ejectable liquid, the passages extending from the inlets on the printhead to openings configured for connection an ejectable liquid supply. Adjacent structures within the laminated structure are laminated together so that the passages funnel the ejectable liquid to the inlets of the printhead.