Nozzle assembly having polymeric coating on moving and stationary portions of roof
View Patent ↗A nozzle assembly for an inkjet printhead. The nozzle assembly includes: a nozzle chamber including a roof having a nozzle opening and a moving portion movable relative to a stationary portion of the roof. An actuator is configured to displace the moving portion relative to the stationary portion and cause ejection of ink through the nozzle opening. A polymeric coating covers the moving portion and the stationary portion. The polymeric coating is absent from a gap between the moving portion and the stationary portion.
1. A nozzle assembly for an inkjet printhead, said nozzle assembly comprising:
a nozzle chamber comprising a roof having a nozzle opening defined therein, said roof comprising a moving portion moveable relative to a stationary portion, such that movement of said moving portion relative to said stationary portion causes ejection of ink through the nozzle opening;
an actuator for moving said moving portion relative to said stationary portion; and
a polymeric coating covering said moving portion and said stationary portion, wherein said polymeric coating is absent from a gap between said moving portion and said stationary portion.
2. The nozzle assembly of claim 1 , wherein said polymeric coating is comprised of polydimethylsiloxane (PDMS).
3. The nozzle assembly of claim 1 , wherein said nozzle opening is defined in said moving portion.
4. The nozzle assembly of claim 1 , wherein said nozzle opening is defined in said stationary portion.
5. The nozzle assembly of claim 1 , 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.
6. The nozzle assembly of claim 5 , wherein said first and second elements are cantilever beams.
7. The nozzle assembly of claim 5 , wherein said thermal bend actuator defines at least part of the moving portion of said roof.
8. The nozzle assembly of claim 1 , wherein each roof forms at least part of a nozzle plate of the printhead, each roof having a hydrophobic outside surface relative to the inside surfaces of each nozzle chamber by virtue of said polymeric coating.
9. The nozzle assembly of claim 1 , wherein said nozzle chamber comprises sidewalls extending between said roof and a substrate, such that said roof is spaced apart from said substrate.
10. The nozzle assembly of claim 9 , wherein said moving portion is configured to move towards said substrate upon actuation of said actuator.
11. An inkjet printhead comprising a plurality of nozzle assemblies according to claim 1 .
12. The inkjet printhead of claim 11 , wherein a nozzle plate of said printhead is coated with said polymeric coating.