Printhead including seal membrane

1. An inkjet printhead comprising a plurality of nozzle assemblies, each nozzle assembly having a moving portion for ejection of ink, said moving portion being moveable relative to a body of the printhead, wherein said printhead is covered with a seal membrane, said seal membrane bridging a gap defined between each moving portion and said body of the printhead.

2. The inkjet printhead of claim 1 , wherein said seal membrane defines, at least partially, an ink ejection face of said printhead.

3. The printhead of claim 1 , wherein said seal membrane is comprised of a polymeric material.

4. The printhead of claim 3 , wherein the polymeric material has a Young's modulus of less than 1000 MPa.

5. The printhead of claim 3 , wherein said polymeric material is hydrophobic.

6. The printhead of claim 5 , wherein said polymeric material recovers its hydrophobicity after being subjected to an O 2 plasma.

7. The printhead of claim 3 , wherein said polymeric material is resistant to removal by an oxidative plasma.

8. The printhead of claim 1 , wherein said polymeric material is selected from the group consisting of: polymerized siloxanes and fluorinated polyolefins.

9. The printhead of claim 1 , wherein the polymeric material is selected from the group consisting of: polydimethvlsiloxane (PDMS) and perfluorinated polyethylene (PFPE).

10. The printhead of claim 1 , wherein each nozzle assembly comprises:

a nozzle chamber having a roof, said roof having said moving portion moveable relative to a static portion and a nozzle opening defined in said roof, such that movement of said moving portion relative to said static portion causes ejection of ink through the nozzle opening;

an actuator for moving said moving portion relative to said static portion; and

at least part of said seal membrane joining said moving portion to said static portion.

11. The printhead of claim 10 , wherein a nozzle plate of said printhead is defined by said static portions.

12. The printhead of claim 10 , wherein said nozzle opening is defined in said moving portion.

13. The printhead of claim 10 , wherein said nozzle opening is defined in said static portion.

14. The printhead of claim 10 , wherein said actuator is a thermal bend actuator 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.

15. The printhead of claim 14 , wherein said first and second elements are cantilever beams.

16. The printhead of claim 14 , wherein said thermal bend actuator defines at least part of the moving portion of said roof, whereby actuation of said actuator moves said actuator towards a floor of said nozzle chamber.

17. The printhead of claim 10 , wherein said seal membrane has a contact angle of more than 90° and the inside surfaces of the nozzle chambers have a contact angle of less than 90°.

18. The printhead of claim 10 , wherein said nozzle chamber comprises sidewalls extending between said roof and a substrate, such that said roof is spaced apart from said substrate.

19. The printhead of claim 18 , wherein said roof and said sidewalls are comprised of a ceramic material depositable by CVD.

20. The printhead of claim 19 , wherein the ceramic material is selected from the group consisting of: silicon nitride, silicon oxide and silicon oxynitride.