Printhead nozzle arrangement having ink ejecting actuators annularly arranged around ink ejection port

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

a wafer defining a plurality of nozzle chambers and a plurality of ink supply channel in fluid communication with the plurality of nozzle chambers for supplying the plurality of nozzle chambers with ink;

an ink ejection port associated with each nozzle chamber; and

a plurality of actuators associated with each nozzle chamber, the plurality of actuators each including a petal formation, wherein

a plurality of petal formations are arranged around an ink ejection port of each nozzle chamber to annularly surround the ink ejection port, and

each actuator is operable to displace a respective petal formation into the nozzle chamber.

2. A printhead as claimed in claim 1 , wherein each actuator comprises an electrically conductive heater element formed in a layer of a plastics material, the heater element being positioned in the plastics material to cause uneven heating, and thereby uneven expansion, of the plastics material, whereby the actuator is displaced into the nozzle chamber.

3. A printhead as claimed in claim 2 , wherein each heater element is formed in a serpentine arrangement in the plastics material.

4. A printhead as claimed in claim 2 , wherein the plastics material is a polytetrafluoroethylene (PTFE) layer, and the heater element is an internal serpentine copper core formed in the PTFE layer.

5. A printhead as claimed in claim 1 , wherein bridges extend radially from a rim defining the ink ejection ports and between adjacent actuators.