Hewlett-packard Company

Glenn W Weberg

Neal W Meyer

Eric G Hanson

Alfred I Pan

Si-Ty Lam

Friedrich Scheu

A thermal inkjet printhead includes unpassivated heater resistors whose resistive material is doped, preferably with oxygen, nitrogen or an equivalent dopant, for increasing the resistance of the material. By increasing the resistance of the resistive material through doping, the drive currents for generating heat within the resistors need not be changed from levels which inkjet printers are presently designed to work with. The printhead of the invention can thus be used in place of a standard printhead without modification to the printer.

Printhead with unpassivated heater resistors having increased resistance

Method of forming a heating element for a printhead

A reusable mandrel and method of making a reusable mandrel is presented. This mandrel has a substrate with a conductive film layer. Upon the conductive film layer, a dielectric mold resides. An etched thin film mandrel is also presented. This mandrel has a substrate covered with a conductive film layer. This conductive film layer is etched to form a mold for the device to be manufactured. These mandrels facilitate the manufacture of high quality precision devices. In particular, they can be used to manufacture orifice plates for thermal ink jet printers by electrodeposition process.

Thin film mandrel

A spinner chuck having a recessed portion for receiving non-circular substrates is used to alleviate uneven build-up of photoresist coatings applied on the substrate. Openings are disposed in the base of the recess about the periphery thereof whereby to drain off coating material spun off into the volume between the substrate and chuck sidewall defining said recess.

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Mountain View, CA, United States of America

Glenn W Weberg