Patent ID: 7134741

Claim:
An ink jet printhead comprising a substrate and a plurality of micro-electromechanical nozzle arrangements positioned on the substrate, each nozzle arrangement comprising: a nozzle chamber positioned on the substrate, the nozzle chamber having a fixed portion extending from the substrate and a movable portion that defines an ink ejection port, the movable portion being displaceable relative to the fixed portion; and an actuator arm connected between the substrate and the movable portion, the actuator arm comprising a heated portion and a non-heated portion, the heated portion being heated in response to an electrical signal, wherein differential thermal expansion between the heated portion and the non-heated portion causes the actuator arm to tilt the movable portion towards the substrate to reduce a volume of the nozzle chamber, and wherein the actuator arm subsequently restores the movable portion to its original position to restore the nozzle chamber volume, thereby ejecting ink from the ink ejection port, wherein the ink ejection port is shaped so that the tilting of the movable portion results in the ejection of a drop of ink in a direction substantially at right angles to the substrate.