PRINTHEAD HAVING HEATER AND NON-HEATER ELEMENTS

1 . A printhead comprising:

a plurality of nozzles;

a plurality of heater elements, each heater element being disposed in a corresponding one of the nozzles and being connected to corresponding electrodes so as to heat fluid within the nozzle thereby forming a gas bubble in the fluid which causes ejection of fluid through the a port in the corresponding nozzle; and

a plurality of non-heater elements formed of the same heater material as the heater elements, each non-heater element being disposed in a corresponding one of the nozzles.

2 . The printhead of claim 1 comprising a substrate having a substrate surface, wherein the areal density of the nozzles relative to the substrate surface exceeds 10,000 nozzles per square cm of substrate surface.

3 . The printhead of claim 1 comprising a structure that is formed by chemical vapor deposition in which the nozzles are incorporated.

4 . The printhead of claim 3 comprising a structure that is less than 10 microns thick in which the nozzles are incorporated.

5 . The printhead of claim 1 wherein the heater and non-heater elements are formed of solid material more than 90% of which, by atomic proportion, is constituted by at least one periodic element having an atomic number below 50.

6 . The printhead of claim 1 wherein each heater element is covered by a conformal protective coating, the coating of each heater element having been applied substantially to all sides of the heater element simultaneously such that the coating is seamless.