The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 06, 1994
Filed:
Apr. 25, 1991
Robert J Miller, Stanford, CA (US);
William R Knight, Corvallis, OR (US);
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
An orificeless thin film printhead for an ink jet pen which comprises a substrate having a plurality of vortex activators thereon, and ink dispensing means located adjacent to the substrate for providing a thin layer of ink of a controlled thickness over the surfaces of the vortex activators. A protective cover is disposed on the surface of the substrate and has one or more slots or other openings therein operative to expose the vortex activators during ink jet printhead operation. When each vortex activator is energized, the energy transferred from the surface of the activator into the liquid film creates a microjet and a shear force therein, followed by the formation of a vortex ring in the ink film. The vortex ring is in turn self-propelled at a relatively low velocity through the ink film to the free liquid surface thereby, producing stress at this surface to allow the high velocity ink at the core of the vortex ring to be efficiently transferred to an adjacent print medium with a high degree of directionality, thereby enhancing resolution and print quality on the printed media. In accordance with the present invention, vortex activators include, but without limitation, heater resistors, piston drivers, and piezoelectric cavities.