Patent ID: 7587822

Claim:
A method of producing an ink jet printhead, the method comprising the steps of: forming a substrate having defined therein a nozzle chamber operable to receive and store a fluid, the chamber fed at one side by an inlet passage; forming a nozzle plate in-situ on the substrate to define a nozzle opening on an opposite side of the nozzle chamber to the inlet passage, the nozzle plate having a thickness of substantially 2 to 2.5 microns; and forming a plurality of heater elements suspended between the nozzle opening and the inlet passage corresponding to each of the nozzles respectively, the heater elements having two opposite planar sides and positioned to be in direct thermal contact with a bubble forming liquid held in the nozzle chamber at both opposed planar sides, wherein at least one of the plurality of heater elements is formed on a different layer to the other of the plurality of heater elements.