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. 23, 1994
Filed:
Apr. 17, 1991
Thomas H Winslow, Corvallis, OR (US);
Paul H McClelland, Corvallis, OR (US);
Donald E Wenzel, Albany, OR (US);
Hewlett-Packard Corporation, Palo Alto, CA (US);
Abstract
An ink-jet pen for storing at below-ambient pressure has an orifice formed therein for providing air bubbles to prevent the back pressure from rising above a level that would cause malfunction of the pen. The amount of air drawn into the reservoir is restricted by the reservoir ink that covers the orifice whenever the pen is in an upright position. The valve operates to occlude the orifice whenever the pen is moved into a position, such as inverted, where the reservoir ink no longer covers the orifice. The occlusion of the orifice prevents the unrestricted flow of ambient air into the reservoir that would otherwise eliminate the required back pressure in the reservoir. The valve includes a sealing liquid selected so that the liquid occludes a passage between the orifice and ambient air without flowing through that passage.