Printhead integrated circuit comprising polymeric cover layer

1. A printhead integrated circuit comprising:

a substrate having drive circuitry; and

a plurality of nozzle assemblies positioned on the substrate, each nozzle assembly having a moving portion moveable relative to a stationary portion for ejection of ink,

wherein said printhead integrated circuit is covered with a polymeric layer, said polymeric layer covering a gap defined between each moving portion and each stationary portion.

2. The printhead integrated circuit of claim 1 , wherein said polymeric layer defines, at least partially, an ink ejection face of said printhead integrated circuit.

3. The printhead integrated circuit of claim 1 , wherein the polymeric layer has a Young's modulus of less than 1000 MPa.

4. The printhead integrated circuit of claim 1 , wherein said polymeric layer is hydrophobic.

5. The printhead integrated circuit of claim 4 , wherein said polymeric layer recovers its hydrophobicity after being subjected to an O 2 plasma.

6. The printhead integrated circuit of claim 1 , wherein said polymeric layer is resistant to removal by an oxidative plasma.

7. The printhead integrated circuit of claim 1 , wherein said polymeric layer is comprised of a material selected from the group consisting of: polymerized siloxanes and fluorinated polyolefins.

8. The printhead integrated circuit of claim 1 , wherein the polymeric layer is comprised of polydimethylsiloxane (PDMS).

9. The printhead integrated circuit 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.

10. The printhead integrated circuit of claim 9 , wherein a nozzle plate of said printhead is defined by said static portions.

11. The printhead integrated circuit of claim 9 , wherein said nozzle opening is defined in said moving portion.

12. The printhead integrated circuit of claim 9 , wherein said nozzle opening is defined in said static portion.

13. The printhead integrated circuit of claim 9 , 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.

14. The printhead integrated circuit of claim 13 , wherein said first and second elements are cantilever beams.

15. The printhead integrated circuit of claim 13 , 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.

16. The printhead integrated circuit of claim 9 , wherein said nozzle chamber comprises sidewalls extending between said roof and a substrate, such that said roof is spaced apart from said substrate.

17. The printhead integrated circuit of claim 16 , wherein said roof and said sidewalls are comprised of a ceramic material depositable by CVD.

18. The printhead integrated circuit of claim 1 , wherein the ceramic material is selected from the group consisting of: silicon nitride, silicon oxide and silicon oxynitride.