Patent ID: 7946687

Claim:
An inkjet nozzle assembly comprising: a nozzle chamber comprising an ink inlet, a floor and a roof, said roof having a moving portion and a nozzle opening; a pair of electrical contacts positioned at one end of said assembly and connected to drive circuitry; and a thermal bend actuator defining at least part of said moving portion, whereby actuation of said actuator moves said moving portion towards said floor, said actuator comprising: an active beam connected to said electrical contacts and extending longitudinally away from said contacts, said active beam defining a bent current flow path between said contacts; and a passive beam fused to said active beam, such that when a current is passed through the active beam, the active beam heats and expands relative to the passive beam, resulting in bending of the actuator, wherein said active beam comprises a resistive heating bar, said heating bar having a relatively smaller cross-sectional area than any other part of the bent current flow path defined by the active beam, such that heating of said active beam is concentrated in said at least one heating bar.