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:
Feb. 12, 1991
Filed:
Dec. 22, 1988
John H Dion, Corvallis, OR (US);
Thomas H Winslow, Corvallis, OR (US);
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
An ink jet print cartridge includes an ink reservoir, a print head for ejecting ink from the reservoir and first and second pressure control mechanisms for limiting the reservoir underpressure. The first pressure control mechanism limits reservoir underpressure by controllably introducing replacement fluid (i.e. air or ink) thereto. The second pressure control mechanism limits reservoir underpressure by changing the volume thereof. The two pressure control mechanisms cooperate to regulate the underpressure in the reservoir at a desired value over a broad range of environmental excursions and permit use of a volumetrically efficient package.