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:
Aug. 13, 1991
Filed:
Jun. 26, 1990
Thomas H Winslow, Corvallis, OR (US);
Bruce A Anderson, Corvallis, OR (US);
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
Underpressure changes in an ink-jet pen (20, 120) reservoir (22, 122) are compensated for by volumetric changes in the reservoir (22, 122) effected by movement of a piston (56, 156) within a sleeve (50, 150) that is connected to the reservoir (22, 122). The piston (56, 156) and sleeve (50, 150) are sized to provide capillarity for holding ink (72, 172) therebetween. The ink (72, 172) between the piston (56, 156) and sleeve (50, 150) acts as a low-friction seal for preventing fluid communication between ambient air and the interior of the resevoir (22, 122). In one embodiment (120), the volumetric efficiency of the pen is enhanced with an auxiliary ink reservoir carried on the piston (156).