Barbara A Parcells

US Patent:

59092319, Jun 1, 1999

Filed:

Oct 30, 1995

Appl. No.:

8/550437

Inventors:

Winthrop D. Childers - San Diego CA
Brian J. Keefe - La Jolla CA
Barbara Parcells - San Diego CA
Frank Drogo - San Marcos CA
Shailendra Kumar - San Diego CA
Steven L. Webb - Temecula CA
Hanno Ix - Escondido CA
Kai Kong Iu - San Diego CA

Assignee:

Hewlett-Packard Co. - Palo Alto CA

International Classification:

B41J 219

US Classification:

347 92

Abstract:

In a inkjet print cartridge ink flows from the reservoir around the edge of the silicon substrate before being ejected out of the nozzles. During operation, warm thermal boundary layers of ink form adjacent the substrate and dissolved gases in the thermal boundary layer of the ink form the bubbles. If the bubbles to grow larger than the diameter of subsequent ink passageways these bubbles choke the flow of ink to the vaporization chambers. This results in causing some of the nozzles of the printhead to become temporarily inoperable. The disclosure describes a method of avoiding such a malfunction in a liquid inkjet printing system by providing a method for reducing residual air bubbles in an inkjet print cartridge by flushing the empty cartridge by passing carbon dioxide through the fill port or the ink ejection nozzles prior to filling the print cartridge with ink and thereby eliminating residual air bubbles from the print cartridge when the print cartridge is filled with ink.