Nozzle device incorporating movement sensor

1. A nozzle device for an inkjet printhead, the nozzle device comprising:

a substrate assembly defining an ink supply;

a chamber-defining layer defining a nozzle chamber in fluid communication with a nozzle opening and the ink supply;

an actuating arm coupled to the substrate assembly, the actuating arm comprising a thermal bend portion and terminating in a paddle separating the ink supply and nozzle chamber, the thermal bend portion configured to pivot during actuation to cause ink within the nozzle chamber to be ejected out through the nozzle opening; and

a movement sensor configured to determine the degree or rate of pivotal movement of the actuating arm, wherein

the actuating arm further includes a bridge between the paddle and the thermal bend portion, the bridge supporting a portion of the chamber-defining layer.

2. A nozzle device as claimed in claim 1 , wherein the movement sensor comprises:

a moving contact element formed integrally with the actuating arm; and

a fixed contact element formed integrally with the substrate assembly and positioned to be contacted by the moving contact element when the actuating arm pivots to a predetermined extent.

3. A nozzle device as claimed in claim 1 , wherein the thermal bend portion of the actuating arm defines an active portion connected electrically to a current source within the substrate assembly.

4. A nozzle device as claimed in claim 3 , wherein the electrical connection is made to end terminals of the actuating arm, and the current source is configured to apply pulsed excitation voltage to said terminals.

5. A nozzle device as claimed in claim 3 , wherein the thermal bend portion of the actuating arm defines a passive portion mechanically coupled to but electrically isolated from the active portion by posts, whereby no current-induced heating occurs within the passive portion, the active portion being located between the passive portion and the substrate assembly.