Patent ID: 7188419

Claim:
A method of producing an ink jet printhead comprising: a structure with a plurality of nozzles each having a nozzle opening through a single surface layer of the structure, the structure formed on an underlying substrate having at least one heater element corresponding to each of the nozzles respectively; the heater elements being configured for thermal contact with a bubble forming liquid for heating at least part of the bubble forming liquid to a temperature above its boiling point to form a gas bubble therein to eject a drop of the liquid through the nozzle openings corresponding to the heater elements in a predetermined direction wherein the method of production comprises the step of: forming the structure in-situ on the substrate so that said surface layer of the structure has a thickness of five microns or less and so that each nozzle opening is defined as a hole through said surface layer having a wall parallel to the predetermined direction, wherein the bubble which each heater element is configured to form is collapsible and has a point of collapse, and wherein each heater element is configured such that the point of collapse of a bubble formed thereby is spaced from that heater element.