Printhead nozzle arrangement with radially disposed actuators

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

a substrate with a layer of drive circuitry, the substrate defining an ink chamber with an ink supply channel etched through the substrate;

a roof structure having a roof layer over the chamber, the roof structure comprises:

a nozzle rim positioned around an ejection port defined in the roof layer above the chamber;

a plurality of actuators radially spaced about, and displaceable with respect to, the nozzle rim, each actuator having an internal copper core for receiving therethrough a current, each actuator configured to thermally expand into the chamber upon receiving the current; and

a series of struts interspersed between the actuators to support the nozzle rim with respect to the roof layer.

2. The roof structure of claim 1 , wherein the actuators are constructed from a material having a coefficient of thermal expansion such that the actuators can perform work during thermal expansion.

3. The roof structure of claim 1 , wherein the substrate defines a number of vias through which the drive circuitry is connected to the actuators.

4. The roof structure of claim 3 , wherein the actuators are manufactured from a polytetrafluoroethylene (PTFE) material and have internal serpentine copper cores connected to the drive circuitry via the vias.

5. The roof structure of claim 1 , wherein the struts include both metal and PTFE portions.

6. The roof structure of claim 1 , wherein the ink chamber is an inverted pyramidal ink chamber with a vertex thereof terminating at the ink supply channel.

7. The roof structure of claim 1 , wherein the ink supply channel is created by means of a deep silicon back etch of the substrate utilizing a plasma etcher.