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. 06, 2002
Filed:
Nov. 02, 1999
David J. Waller, Fort Collins, CO (US);
Melissa D. Boyd, Corvallis, OR (US);
John M. Koegler, III, Corvallis, OR (US);
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
An actively-controlled recirculating ink delivery system is provided that incorporates active control of pressures downstream of the printhead. This is achieved through the use of a device (such as a pump, return valve, combination thereof or similar devices) that provides active control of downstream ink pressures. A pressurized ink supply, pressure sensors, an air and heat exchanger are also provided, thereby improving start up, normal operation, purging and shut down procedures. Because the pressurized ink supply is not restricted to sit at a particular vertical distance below the printhead, backpressure may be changed quickly and easily through electronic control, and system priming is considerably quicker than with conventional air-pressurized systems.