Karen Cheung

US Patent:

61765732, Jan 23, 2001

Filed:

Nov 15, 1999

Appl. No.:

9/440834

Inventors:

Phillip W. Barth - Portola Valley CA
William H. McAllister - Saratoga CA
Storrs Hoen - Brisbane CA
Karen C. Cheung - San Jose CA

Assignee:

Agilent Technologies Inc. - Palo Alto CA

International Classification:

B41J 219

US Classification:

347 92

Abstract:

A control device for regulating the flow of gas through a liquid utilizes capillary forces to manage gas retention and utilizes thermal energy to execute a gas release operation. A capillary path within the control device has an opening to a reservoir of liquid and has a geometry by which gas flow is inhibited by capillary forces on a liquid volume within the path. An equilibrium condition is established at the interface of the liquid and gas. However, a heater is in thermal communication with the capillary path for selectively heating the contained volume of liquid sufficiently to free the flow of air through the path. In a preferred application, the control device is employed in an ink cartridge to release accumulated air at selected times. By heating ink within the capillary path to a temperature above the boiling point of ink, the equilibrium condition at the air-to-ink interface is overcome. In addition to the capillary path, there preferably is a liquid-fill maintenance path that ensures that the capillary path is refilled following each release operation.