Micro-electromechanical fluid ejection mechanism having a shape memory alloy actuator

1. A micro-electromechanical fluid ejection mechanism comprising:

a substrate defining an ink passage in fluid communication with a tapered ink chamber having an ink ejection port; and

a shape memory alloy (SMA) actuator arranged within the chamber, the actuator configured to straighten when heated and to return to a bent state upon subsequent cooling to facilitate ejection of ink via the ejection port.

2. The micro-electromechanical fluid ejection mechanism of claim 1 , wherein the substrate comprises a multilayered substrate including control and drive circuitry to facilitate actuation of the SMA actuator.

3. The micro-electromechanical fluid ejection mechanism of claim 2 , wherein the actuator includes a serpentine heating element which is electrically coupled to the control and drive circuitry.

4. The micro-electromechanical fluid ejection mechanism of claim 3 , wherein the actuator further comprises a pair of silicon-based layers with the heating element interposed between the silicon-based layers.

5. The micro-electromechanical fluid ejection mechanism of claim 4 , wherein one of the silicon-based layers comprises silicon dioxide material whereas the other silicon-based layer comprises silicon nitride.

6. The micro-electromechanical fluid ejection mechanism of claim 5 , wherein each silicon-based layer extends from a layer of corresponding material in the multi-layered substrate.

7. The micro-electromechanical fluid ejection mechanism of claim 2 , further comprising a pair of metal interconnects which each couple a respective end of the heating element to the control and drive circuitry.