Ink ejection nozzle with a paddle having a series of protrusions to reduce outward ink flow

1. An ink ejection nozzle for a printhead integrated circuit, the nozzle comprising:

a fluid chamber having a fluid outlet port and a fluid inlet port respectively defined in opposite walls of the chamber, the chamber having chamber wall edge portions for locating a paddle therebetween; and

a paddle located in the chamber between the edge portions, the paddle operatively displaceable to eject ink from the fluid outlet port, wherein the paddle is formed with a series of protrusions in a central portion of the paddle, the protrusions aiding in reducing outward ink flow from the centre of the paddle as the paddle moves towards the fluid outlet port to eject ink via the outlet port; wherein,

the paddle is spaced from the chamber wall edge portions so that ink is able to flow between a front and rear of the paddle to allow refilling of the chamber with ink via the inlet port, and the chamber wall edge portions are configured to reduce fluid flow through space between said portions and the paddle when the paddle moves from a rest position to an ejection position.

2. The ejection nozzle of claim 1 , wherein the series of protrusions includes a plurality of truncated pyramidal protrusions.

3. The ejection nozzle of claim 1 , wherein the protrusions include a series of ridges, said ridges arranged on parallel, concentric or intersecting fashion, and said ridges shaped to be elliptical, circular, or arcuate.

4. The ejection nozzle of claim 1 , wherein the inlet port is configured to encourage fluid flow into the chamber as the paddle moves from the ejection position to the rest position.

5. The ejection nozzle of claim 4 , having a formation angularly disposed into the chamber from a surface of the wall of the chamber about the fluid inlet port.