Inkjet nozzle assembly having thermoelastic actuator beam disposed on nozzle chamber roof
View Patent ↗An inkjet nozzle assembly comprises a nozzle chamber having a floor and a roof, the roof having a nozzle opening defined therein. A moving portion defines part of the roof so that the moving portion is moveable towards the floor. A thermal actuator defines part of the moving portion. The thermal actuator comprises 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. The first active beam is disposed on an upper surface of the passive beam relative to the floor.
1. An inkjet nozzle assembly comprising:
a nozzle chamber comprising a floor and a roof, said roof having a nozzle opening defined therein,
a moving portion defining at least part of said roof, said moving portion being moveable towards the floor,
a thermal actuator defining at least part of said moving portion, said thermal 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 said first active beam is disposed on an upper surface of said passive beam relative to said floor.
2. The inkjet nozzle assembly of claim 1 , wherein the first active beam defines at least 30% of a total area of the roof.
3. The inkjet nozzle assembly of claim 1 , wherein the nozzle opening is defined in the moving portion, such that the nozzle opening is moveable relative to the floor.
4. The inkjet nozzle assembly of claim 1 , wherein said nozzle opening is defined in a stationary portion of said roof.
5. The inkjet nozzle assembly of claim 4 , wherein the actuator is moveable relative to the nozzle opening.
6. The inkjet nozzle assembly of claim 1 , wherein the first beam is defined by a tortuous beam element, said tortuous beam element having a plurality of contiguous beam members.
7. The inkjet nozzle assembly of claim 6 , wherein the tortuous beam element comprises a plurality of longer beam members and at least one shorter beam member, each longer beam member extending along a longitudinal axis of the first beam and being interconnected by a shorter beam member extending across a transverse axis of the first beam.
8. The inkjet nozzle assembly of claim 1 , wherein the first beam is fused to the second beam by a CVD deposition process.
9. The inkjet nozzle assembly of claim 1 , wherein the first beam is comprised of a material selected from the group consisting of: titanium nitride, titanium aluminium nitride and an aluminium alloy.
10. The inkjet nozzle assembly of claim 1 , wherein the first beam is comprised of an aluminium alloy.
11. The inkjet nozzle assembly of claim 10 , wherein said aluminium alloy comprises aluminium and at least one other metal having a Young's modulus of more than 100 GPa.
12. The inkjet nozzle assembly of claim 11 , wherein said at least one metal is selected from the group comprising: vanadium, manganese, chromium, cobalt and nickel.
13. The inkjet nozzle assembly of claim 11 , wherein said alloy comprises aluminum and vanadium.
14. The inkjet nozzle assembly of claim 13 , wherein said alloy comprises at least 80% aluminium.
15. An inkjet printhead comprising a plurality of nozzle assemblies according to claim 1 .