This patent describes an ink jet printer where ink is ejected from a nozzle chamber by means of the utilisation of the electrostatic attraction between two parallel plates. An electrostatic actuator includes a first planar electrode formed within a bottom and a moveable second planar electrode arranged above the first planar electrode. The second planar electrode is moveable to a pre-firing position adjacent to the first planar electrode, thereby causing a corrugated border portion of the second electrode to concertina. Upon reduction of a potential difference, the corrugated border returns to its quiescent position, thereby causing the ejection of ink from the nozzle chamber. Between the first planar electrode and the second planar electrode is an air gap interconnected to an external atmosphere at a side of the nozzle chamber such that air flows into and out of the gap upon movement of the actuator.

An ink jet printhead chip that is the product of an integrated circuit fabrication technique includes a wafer substrate having a front surface and a rear surface. A plurality of ink passages are defined through the wafer substrate, so that each ink passage defines an inlet at a rear surface of the wafer substrate and an outlet at a front surface of the wafer substrate. Each ink passage is in fluid communication with an ink supply at the rear surface of the wafer substrate. A plurality of actuators are positioned on the rear surface of the wafer substrate and are operatively arranged with respect to the ink passages to generate an ink flow through each passage, from the rear surface to the front surface, when activated.

This patent describes an ink jet printer based around ink jet nozzles which utilize a pump action so as to rapidly refill a nozzle chamber for ejection of subsequent ink drops. The nozzle chamber includes a first actuator for ejecting ink and a second actuator for pumping ink into the nozzle chamber. The actuators can comprise thermal bend actuators having a conductive heater element encased within a material having a high co-efficient of thermal expansion. The heater element is of a serpentine form and is concertinaed upon heating.

A nozzle arrangement for an ink jet printhead includes a substrate. Nozzle chamber walls are arranged on the substrate to define a nozzle chamber. An ejection actuator is operatively positioned with respect to the nozzle chamber and is displaceable between an inoperative condition and an operative condition to eject ink from the nozzle chamber. The ejection actuator includes an actuating mechanism to facilitate such displacement. A refilling actuator is operatively positioned with respect to the nozzle chamber and is displaceable between an inoperative condition and an operative condition to direct ink into a zone in which the ink can be acted on by the ejection actuator, subsequent to the ejection of ink from the nozzle chamber. The refill actuator includes an actuating mechanism to facilitate such displacement.

The invention includes processes and products made by the processes. The processes include making forms and parts by friable mold casting or die casting using molten Nitinol poured or injected into the mold or die. After the Nitinol has cooled to a solid state, it is removed from the mold by disintegrating the friable material of the mold and is heated to an elevated temperature under high pressure to consolidate the Nitinol and remove any internal voids. The parts and forms are then heat treated to reduce brittleness and improve toughness and impact strength. The part may be hot machined to reduce it to near net size, and may be ground to reduce the part to the exact specified part size. For example, cylindrical parts can be centerless ground; balls can be ground in a conventional ball grinder; flat stock can be surface ground. For parts requiring a smooth surface finish, polishing or lapping provides the specified surface finish on the part, down to 0.5 microinch RMS or finer. The part may be heat treated to obtain the desired hardness, from RC40 to RC65. An integral surface oxide of any of several colors can be formed on the surface of the part. The oxide surface may itself be polished to an even finer surface finish. Shape memory effect may be obtained in Type 60 Nitinol parts and forms that have been hot-worked by heat treating to about 675.degree. C.-700.degree. C. and oven cooling slowly over 8-10 hours to ambient temperature.