Inkjet nozzle assembly incorporating a fluidic seal

1. An inkjet nozzle assembly for a printhead integrated circuit, the nozzle assembly being configured to be replicated on a wafer substrate incorporating drive circuitry so that the printhead integrated circuit comprises an array of the nozzle assemblies, the nozzle arrangement comprising

a static nozzle chamber structure extending from the wafer substrate and bounding an ink inlet channel defined through the wafer substrate;

a dynamic nozzle chamber structure arranged on the static nozzle chamber structure so that the static and dynamic nozzle chamber structures together define a nozzle chamber in fluid communication with the ink inlet channel, the dynamic nozzle chamber structure defining an ink ejection port and being displaceable relative to the substrate so that ink is ejected from the ink ejection port due to volumetric change in the nozzle chamber;

an actuating mechanism fast with the substrate and the dynamic nozzle chamber structure and electrically connected to the drive circuitry to receive drive signals from the drive circuitry so that the dynamic nozzle chamber structure is reciprocally displaced to eject ink from the ink ejection port, wherein

the dynamic and static nozzle chamber structures are configured to define a fluidic seal interposed between the structures when the nozzle chamber is filled with ink.

2. An inkjet nozzle assembly as claimed in claim 1 , which includes a floor portion, the static nozzle chamber structure being a wall portion that bounds the ink inlet channel and extends from the floor portion.

3. An inkjet nozzle assembly as claimed in claim 2 , in which the dynamic nozzle chamber structure includes a crown portion that defines the ink ejection port and a skirt portion that depends from the crown portion such the wall portion of the static nozzle chamber structure and the skirt portion together define a peripheral wall of the nozzle chamber.

4. An inkjet nozzle assembly as claimed in claim 3 , in which an inwardly directed lip is arranged on a free end of the wall portion, the lip and an edge of the skirt portion co-operating to define said fluidic seal.

5. An inkjet nozzle assembly as claimed in claim 1 , in which the actuating mechanism comprises an elongate, micro-electromechanical actuator fast at one end to the substrate and connected to the drive circuitry and an elongate connecting member fast with and interposed between the actuator and the dynamic nozzle chamber structure.

6. An inkjet nozzle assembly as claimed in claim 5 , which includes an anchor that extends from the substrate, the actuator being a thermal bend actuator that is fast with and extends from the anchor.

7. An inkjet nozzle assembly as claimed in claim 6 , in which the actuator includes an active beam and a passive beam interposed between the active beam and the substrate, at least the active beam defining a heating circuit connected to the conductive pads and capable of thermal expansion, the beams being fast with respect to each other with the passive beam electrically isolated so that the actuator experiences differential thermal expansion when a current is set up in the active beam, thus causing the actuator and the dynamic nozzle chamber structure to deflect towards the substrate.