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. 19, 1991
Filed:
Dec. 16, 1988
Thomas H Winslow, Corvallis, OR (US);
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
An ink jet pen has two modes of operation, a normal speed mode and a high speed mode. In the normal speed mode, the pen's ink reservoir is maintained at a desired below-atmospheric pressure by a bubble generator orifice that introduces air from an atmospherically vented chamber into the reservoir to relieve the partial vacuum caused by ejection of ink. In the high speed mode, a heater heats air trapped in the ink reservoir. As the air tries to expand, it pressurizes the ink and causes it more quickly to refill the pen's ink-ejecting nozzle after firing. The pen can thus be fired at a faster rate. The bubble generator orifice is blocked during the high speed mode by the first droplet of ink expelled through the orifice, which acts to wet and seal a vent tube.