Thermal bend actuator comprising aluminium alloy

1. A thermal bend actuator, having a plurality of elements, comprising:

a first active element for connection to drive circuitry; and

a second passive element mechanically cooperating with the first element, such that when a current is passed through the first element, the first element expands relative to the second element, resulting in bending of the actuator,

wherein the first element is comprised of an aluminium alloy, said aluminium alloy comprising aluminium and at least 5% vanadium.

2. The thermal bend actuator of claim 1 , wherein said alloy comprises at least 80% aluminium.

3. The thermal bend actuator of claim 1 , wherein said first and second elements are cantilever beams.

4. The thermal bend actuator of claim 3 , wherein the first beam is fused or bonded to the second beam along a longitudinal axis thereof.

5. The thermal bend actuator of claim 3 , wherein at least part of the second beam is spaced apart from the first beam, thereby insulating the first beam from at least part of the second beam.

6. The thermal bend actuator of claim 1 , wherein one of said plurality of elements is comprised of a porous material.

7. The thermal bend actuator of claim 6 , wherein said porous material has a dielectric constant of about 2 or less.

8. The thermal bend actuator of claim 6 , wherein said porous material is porous silicon dioxide.

9. The thermal bend actuator of claim 3 , wherein a third insulation beam is sandwiched between the first beam and the second beam.

10. The thermal bend actuator of claim 9 , wherein the third insulation beam is comprised of a porous material.

11. The thermal bend actuator of claim 4 , wherein the second beam is comprised of a porous material.

12. An inkjet nozzle assembly comprising:

a nozzle chamber having a nozzle opening and an ink inlet; and

a thermal bend actuator, having a plurality of cantilever beams, for ejecting ink through the nozzle opening, said actuator comprising:

a first active beam for connection to drive circuitry; and

a second passive beam mechanically cooperating with the first beam, such that when

a current is passed through the first beam, the first beam expands relative to the second beam, resulting in bending of the actuator,

wherein the first beam is comprised of an aluminium alloy, said aluminium alloy comprising aluminium and at least 5% vanadium.

13. The inkjet nozzle assembly of claim 12 , wherein the nozzle chamber comprises a floor and a roof having a moving portion, whereby actuation of said actuator moves said moving portion towards said floor.

14. The inkjet nozzle assembly of claim 13 , wherein the moving portion comprises the actuator.

15. The inkjet nozzle assembly of claim 13 , wherein the first active beam defines at least 30% of a total area of the roof.

16. The inkjet nozzle assembly of claim 14 , wherein the first active beam defines at least part of an exterior surface of said nozzle chamber.

17. The inkjet nozzle assembly of claim 14 , wherein the nozzle opening is defined in the moving portion, such that the nozzle opening is moveable relative to the floor.