Abstract: This application discloses a thermal ink jet printhead and method of manufacture featuring an improved all-metal orifice plate and barrier layer assembly. This assembly includes constricted ink flow ports to reduce cavitation damage and smooth contoured convergent ink ejection orifices to prevent "gulping" of air during an ink ejection process. Both of these features extend the maximum operating frequency, fmax, of the printhead. The nickle barrier layer and the underlying thin film resistor substrate are gold plated and then soldered together to form a good strong solder bond at the substrate-barrier layer interface.

Abstract: The present invention is directed to a compound bore nozzle plate for a thermal ink jet printhead and is manufactured by electroforming nickel onto a nickel substrate which has been masked by a plurality of mask segments of predefined geometry. This geometry consists of a plurality of base segments upon which have been formed a corresponding plurality of post segments of greater vertical dimension and smaller lateral dimension than the base segments. This mask geometry enables greater center-to-center orifice spacing to be achieved without unacceptably reducing the thickness and structural integrity of the nozzle plate.

Abstract: A passivation layer in a thermal ink jet printhead is formed or "grown" by a reaction between the materials of the ink jet structure to be protected and an element which will form a chemically inert, electrically insulating, thermally conductive compound. The resistor structure may be of tantalum or tantalum nitride and the electrical conductors therefor may be of aluminum. By subjecting this resistor-conductor structure to a reactive oxide atmosphere, the exposed surfaces of both are anodized so that a surface film of aluminum oxide is formed on the aluminum conductor and a surface film of tantalum pentoxide or tantalum oxynitride is formed on the resistor structure.