Patent ID: 7188933

Claim:
A printhead integrated circuit which comprises a substrate that incorporates a drive circuitry layer and defines a plurality of nozzle chambers and respective ink supply channels in fluid communication with the nozzle chambers; a plurality of ink ejection nozzles positioned on the substrate to be in fluid communication with respective nozzle chambers; and a plurality of thermal actuators connected to the drive circuitry layer and reciprocally displaceable with respect to the substrate on receipt of an electrical signal from the drive circuitry layer, at least one actuator being associated wit each respective nozzle chamber, the actuators being positioned so that reciprocal displacement of each actuator results in reduction and subsequent enlargement of each respective nozzle chamber to eject ink drops from the respective nozzles, wherein each actuator at least partially defines a wall of a respective nozzle chamber, said wall having one of said ink ejection nozzles defined therein.