JET NOZZLE STRUCTURE FOR ELECTROHYDRODYNAMIC DROPLET FORMATION AND INK JET PRINTING EM THEREWITH

JET NOZZLE STRUCTURE FOR ELECTROHYDRODYNAMIC DROPLET FORMATION AND INK JET PRINTING SYSTEM THEREWITH The practice of this disclosure obtains a monolithic structure useful for electrohydrodynamically synchronizing the formation of droplets in a jet stream exiting from a jet nozzle. The monolithic structure is primarily adaptable for ink jet printing. The jet nozzle structure provided by the practice of this disclosure includes a jet nozzle design in a crystalline semiconductor block, e.g., of silicon (Si), germanium (Ge) or gallium arsenide (GaAs), with an electrode structure which is integrally incorporated therewith whereby a variable electric field is established proximate to the orifice of the jet nozzle structure. The electric field electrohydrodynamically perturbs the jet stream emitting from the jet nozzle structure so that formation of drops in the jet stream is controllably achieved, e.g. synchronously when the variable electric field is oscillating with a given periodicity. In an exemplary practice of this disclosure, a conductive region is integrally incorporated with a jet nozzle design formed from a block or wafer or substrate of single crystalline silicon either in or on said nozzle whereby a varying electric field is established proximate to the orifice such that the jet stream is temporally and spatially influenced electrohydrodynamically by said electric field. For a particular design of the conductive region, a doped Si region in the Si substrate is utilized therefor. In the fabrication of a particular type of jet nozzle design, which utilizes a block of single crystalline silicon during the fabrication of the jet nozzle, there is included a diffused p+ region and an insulation layer which is formed either unitary therewith, e.g., by oxidation, or is formed ancillary thereto by deposition of an insulation layer. When a synchronizing signal is applied to said p+ silicon layer, an oscillating electric field is established proximate to the orifice of the jet nozzle. There is achieved by the practice of this disclosure a monolithic device for ink jet printing with a plurality of jets which are controllable either independently or cooperatively through appropriate integrated silicon semi-conductor circuitry.