Inkjet printhead device having nozzle guard and ink containment formations

1. An inkjet printhead device which comprises

a substrate that defines a plurality of ink passages;

drive circuitry positioned on the substrate;

a plurality of nozzle chamber structures positioned on the substrate, each nozzle chamber structure defining a nozzle chamber in fluid communication with at least one respective ink passage and an ink ejection port in fluid communication with the nozzle chamber;

a plurality of actuators connected to the drive circuitry and operative to eject ink from respective nozzle chamber structures upon receipt of electrical signals from the drive circuitry;

a nozzle guard that is positioned on the substrate and spaced from the nozzle chamber structures, the nozzle guard defining a plurality of apertures substantially aligned with respective ink ejection ports; and

a plurality of containment walls interposed between the nozzle guard and the substrate and defining containment chambers, each containment chamber enclosing at least one nozzle chamber structure to confine leakage of ink to said respective at least one nozzle chamber structure;

wherein each nozzle chamber structure includes a movable structure with a crown portion that defines the ink ejection port and a skirt portion that depends from the crown portion and a wall portion that bounds the associated ink passage, the movable structure being displaceable towards the substrate with the skirt portion overlapping the wall portion and away from the substrate so that ink is ejected from the ink ejection port.

2. An inkjet printhead device as claimed in claim 1 , in which the skirt portion and the wall portion of each nozzle chamber structure are shaped so that ink in the nozzle chamber can form a meniscus between the skirt portion and the wall portion to define a fluidic seal, thereby inhibiting the egress of ink during operation.

3. An inkjet printhead device as claimed in claim 1 , in which each actuator is elongate with one end anchored to the substrate and an opposed end connected to a respective movable structure, the actuator being displaceable on receipt of said electrical signals to displace the movable structure.

4. An inkjet printhead device as claimed in claim 3 , in which each actuator includes an active beam and a passive beam, the active beam defining an electrical heating circuit that is connected to the drive circuitry, the beams being electrically isolated from each other with the passive beam interposed between the active beam and the substrate such that heating and subsequent cooling of the active beam on receipt of an electrical pulse results in differential thermal expansion and subsequent contraction of the actuator so that the actuator is bent towards and away from the substrate thereby reciprocally displacing the respective movable structure to eject ink from the ink ejection port.

5. An inkjet printhead device as claimed in claim 1 , in which the substrate and the nozzle guard are of the same material.

6. An inkjet printhead device as claimed in claim 5 , in which the substrate and the nozzle guard are of silicon.