Patent ID: 7794059

Claim:
A nozzle for an inkjet printhead, the nozzle comprising: a wafer assembly defining an ink supply channel, said wafer assembly including a CMOS drive circuitry layer and electrodes coupled to the drive circuitry layer; a chamber roof layer supported by the wafer assembly, and defining a nozzle chamber in fluid communication with the ink supply channel and a nozzle aperture through which ink in the nozzle chamber can be ejected; and a thermal actuator sandwiched between the wafer assembly and the chamber roof layer, the thermal actuator including a heater element which, upon actuation, ejects ink from the nozzle chamber out through the nozzle aperture; wherein the chamber roof layer defines: a nozzle rim projection encircling said nozzle aperture; and a plurality of columnar projections spaced across the chamber roof layer, and wherein said nozzle rim projection projects a same height from said chamber roof layer as said columnar projections.