PRINTHEAD HAVING RELATIVELY SIZED FLUID DUCTS AND NOZZLES

1 . A printhead comprising:

a substrate having a droplet ejection side and a liquid supply side opposite the droplet ejection side;

at least one nozzle formed on the droplet ejection side of the substrate, the nozzle having a drop ejection actuator and an associated drop ejection aperture for ejecting drops of liquid;

ducting extending from the liquid supply side into the substrate and terminating before reaching the droplet ejection side; and

at least one liquid inlet for establishing fluid communication between the ducting and the nozzle,

wherein the ducting has a smaller cross section transverse to flow direction than that of the drop ejection aperture of the nozzle.

2 . A printhead according to claim 1 wherein the nozzle has a chamber for holding a quantity of the liquid to be ejected, the chamber having a roof layer in which the drop ejection aperture is formed and the liquid inlet is positioned in a chamber wall that is opposite the roof layer.

3 . A printhead according to claim 2 wherein the drop ejection actuator has a portion positioned between the drop ejection aperture and the liquid inlet.

4 . A printhead according to claim 3 wherein the chamber has a first drop ejection aperture and a second drop ejection aperture formed in the roof layer and is divided into a first part and a second part with the first drop ejection aperture positioned in the first part and the second drop ejection aperture positioned in the second part.

5 . A printhead according to claim 4 wherein the drop ejection actuator has a first heater and second elements respectively associated with the first and second parts of the chamber.

6 . A printhead according to claim 5 wherein the drop ejection actuator is formed from polytetrafluoroethylene.