Inkjet printhead having ink flow preventing actuators

1. An inkjet printhead comprising:

an ink supply channel;

a plurality of actuators, each actuator comprising a conductive heater, a paddle, and an arm interconnecting the heater and paddle; and

a plurality of ink ejection chambers, each chamber having a first wall in which a first aperture for ink ejection is defined, a second wall in which a second aperture is defined through which the arm of an associated actuator passes so that the heater is outside the chamber and the paddle is inside the chamber, and a third wall in which a third aperture is defined through which ink from the ink supply channel is communicated,

wherein the arm of each actuator incorporates a protruding shield configured to restrict the flow of ink through the associated second aperture.

2. A printhead as claimed in claim 1 , wherein the shield of each actuator arm incorporates a hydrophobic surface.

3. A printhead as claimed in claim 1 , wherein the shield of each actuator arm is formed on an upper surface of the arm, and, in use, the arm of each actuator is moved in an upwardly defined direction towards the first aperture of the associated chamber.

4. A printhead as claimed in claim 1 , wherein the actuator comprises thermally expansible material.

5. A printhead as claimed in claim 1 , wherein the shield of each actuator arm is arranged adjacent the second aperture of the associated chamber.