Printhead integrated circuit with electromechanical actuators incorporating heatsinks

1. A printhead integrated circuit comprising:

an array of nozzles;

a plurality of micro-electromechanical actuators associated with each nozzle respectively for ejecting ink there through;

each of the micro-electromechanical actuators having an activation arm that is configured for thermal expansion by resistive heating in response to an electrical activation signal, and a heat sink contacting the activation arm for enhancing heat dissipation from the activation arm after the activation signal.

2. A printhead integrated circuit according to claim 1 further comprising a substrate and drive circuitry positioned on the substrate, wherein a plurality of nozzle chamber structures are positioned on the substrate, each nozzle chamber structure associated with a nozzle respectively and configured to hold a quantity of ink.

3. A printhead integrated circuit according to claim 2 wherein the micro-electromechanical actuators are fixed to the substrate and further comprise an actuator arm positioned in the chamber of the associated nozzle such that activation of the activation arm moves the actuator arm relative to the substrate.

4. A printhead integrated circuit according to claim 3 wherein each of the micro-electromechanical actuators further comprise a passive arm fixed at one end relative to the activation arm such that differential thermal expansion between the passive arm and the activation arm causes the actuation arm to move relative to the substrate.

5. A printhead integrated circuit according to claim 4 wherein at least one strut is extends between the activation arm and the passive arm.

6. A printhead integrated circuit according to claim 5 wherein the at least one of the struts of each actuator defines the heat sink.

7. A printhead integrated circuit according to claim 6 wherein each strut is configured to inhibit buckling of the actuator during use.

8. A printhead integrated circuit according to claim 7 wherein the activation arm and the passive arm are substantially parallel and wherein each strut is oriented substantially at right angles to the activation and passive arms.

9. A printhead integrated circuit according to claim 8 wherein an ink ejection member is fast with each respective actuator arm and is received in a respective nozzle chamber to eject ink from the nozzle chamber.

10. A printhead integrated circuit according to claim 9 wherein the activation members of each pair arm and the passive arm have substantially the same configuration.

11. A printhead integrated circuit as claimed in claim 10 wherein each activation member is substantially of a semi-conductor material.

12. A printhead integrated circuit as claimed in claim 11 wherein each activation arm is of titanium nitride.