Printhead incorporating a two dimensional array of ink ejection ports

1. A printhead for an inkjet printer, the printhead comprising:

a wafer substrate assembly defining rows of evenly spaced ink inlet channels; and

rows of ink ejection nozzle arrangements extending from the wafer substrate assembly and in fluid communication with respective ink inlet channel rows, each nozzle arrangement defining an ink ejection port from which ink can be ejected, adjacent rows of ink ejection nozzle arrangements being axially offset relative to each other so that the resulting two dimensional array of ink ejection ports is a non-orthogonal grid.

2. A printhead as claimed in claim 1 , wherein each nozzle arrangement is substantially rectangular without gaps between adjacent rows of nozzle arrangements, such that adjacent rows are continuous.

3. A printhead as claimed in claim 2 , without gaps between adjacent nozzle arrangements in each row, such that adjacent nozzle arrangements are continuous.

4. A printhead as claimed in claim 1 , wherein the rows of ink ejection nozzle arrangements are alternately positioned along their respective axes.

5. A printhead as claimed in claim 1 , wherein the ink ejection ports are aligned with respective ink inlet channels.

6. A printhead as claimed in claim 1 , wherein each nozzle arrangement comprises:

an elongate lever arm pivotally mounted relative to the wafer substrate assembly;

a nozzle chamber structure defining a nozzle chamber for receiving ink from one of the ink inlet channels, the nozzle chamber structure comprising a static portion extending from the wafer substrate assembly and defining one of the ink ejection ports through which ink in the nozzle chamber can be ejected, the nozzle chamber structure further comprising a movable wall portion mounted to the lever arm at a location such that the lever arm terminates in a free end within the nozzle chamber; and

a thermal actuator operatively mounted to the wafer substrate assembly and coupled to the lever arm such that, upon actuation, the thermal actuator pivots the lever arm to move its free end within the nozzle chamber and thereby eject ink in the nozzle chamber from said ink ejection port.

7. A printhead as claimed in claim 6 , wherein the thermal actuator comprises:

an anchor extending from the wafer substrate assembly; and

a pair of actuator arms extending from the anchor towards the lever arm which, in use, bend as a result of differential thermal expansion.