Variable-volume nozzle arrangement

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

a substrate assembly defining an ink inlet;

a static ink ejecting member extending from the substrate assembly and bounding the ink inlet;

an active ink ejecting member having a roof and sidewalls that depends from the roof towards the substrate, the roof defining an ink ejection port and the active ink ejecting member movably located relative to the static ink ejecting member to define a variable-volume nozzle chamber; and

an actuator arrangement configured to reciprocate the active ink ejection member relative to the static ink ejecting member to eject ink in the nozzle chamber out through the ink ejection port, wherein

the static ink ejecting member is located within bounds delimited by the sidewalls of the active ink ejecting member and includes a sealing formation extending towards the sidewalls, the sealing formation for forming a fluidic seal with the sidewall, and

the sealing formation is provided at an upper edge of the static ink ejecting member, and shaped to extend outwards and downwards with respect to the upper edge of the static ink ejecting member.

2. A nozzle arrangement as claimed in claim 1 , wherein ink ejection port is aligned with the ink inlet.

3. A nozzle arrangement as claimed in claim 1 , wherein the static ink ejecting member includes a ledge that extends horizontally towards a position above the ink inlet.

4. A nozzle arrangement as claimed in claim 1 , wherein the actuator arrangement includes a pair of symmetrically opposed thermal actuators that act on the roof to eject the ink, each thermal actuator being connected to drive circuitry of the substrate assembly.

5. A nozzle arrangement as claimed in claim 4 , wherein each thermal actuator is in the form of a bend actuator and a connecting structure is positioned intermediate each thermal actuator and the roof.