Pagewidth inkjet printhead incorporating an array of nozzle arrangements

1. A pagewidth inkjet printhead that comprises

a substrate that defines a plurality of ink inlet passages and incorporates drive circuitry; and

a plurality of substantially identical nozzle arrangements positioned on the substrate, each nozzle arrangement being generally elongate with an ink ejection port in fluid communication with an ink inlet channel at one end, wherein

the nozzle arrangements form an array on the substrate, the array being defined by replicating one nozzle arrangement on a grid according to a replication hierarchy that includes an initial acute angle rotation relative to a print media feed direction, in which each nozzle arrangement comprises

an elongate actuator that is connected to or integral with the substrate at a first end, the elongate actuator including a heating circuit that is capable of imparting thermal differential expansion and contraction to the elongate actuator to generate reciprocating movement of a second end of the actuator towards and away from the substrate;

nozzle chamber walls positioned on the substrate to define a nozzle chamber in fluid communication with a respective ink inlet passage and the ink ejection port in fluid communication with the nozzle chamber; and

an ink ejection member positioned in the nozzle chamber and connected to or intregral with the second end of the actuator such that in use, said reciprocating movement of the second end of the actuator results in the ejection of ink from the ink ejection port.

2. A pagewidth inkjet printhead as claimed in claim 1 , in which the replication hierarchy includes an initial rotation of substantially 45 degrees.

3. A pagewidth inkjet printhead as claimed in claim 2 , in which the array includes at least one set of corresponding pairs of nozzle arrangements, the replication hierarchy including a rotation through substantially 180 degrees of one of the nozzle arrangements of each pair.

4. A pagewidth inkjet printhead as claimed in claim 3 , in which the array includes a number of sets of corresponding pairs of nozzle arrangements, each set being in fluid communication with ink inlet passages for carrying ink of a color associated with that set.

5. A pagewidth inkjet printhead as claimed in claim 4 , in which a predetermined number of nozzle arrangements are in fluid communication with a single ink inlet passage, the replication hierarchy including a replication of said predetermined number of nozzle arrangements a predetermined number of times to form at least one group of nozzle arrangements.

6. A pagewidth inkjet printhead as claimed in claim 5 , which includes a number of printhead chips that are positioned to span a print medium in use, each printhead chip incorporating one of said groups of nozzle arrangements.