Hewlett-packard Company

Christopher J Shultz

Joseph Edward Scheffelin

David S Hunt

Elizabeth Zapata

Mark E Young

Alfred U Zepeda

Jon J Fong

John M Wade

Max Stephen Gunther

Betsy C Huntingdon

Robert Joseph Katon

An inkjet print cartridge is described which has a first fill port, for initially filling the print cartridge with ink, and a refill port for recharging the print cartridge. The refill port includes a slideable valve which is engageable with a valve on an external ink reservoir to create an airtight fluid communication path between the print cartridge reservoir and the external ink reservoir.

Refilling technique for inkjet print cartridge having two ink inlet

An inkjet cartridge is adapted to receive ink from an external ink supply reservoir. The inkjet cartridge includes an internal reservoir, printhead, housing, and fluid interface. The housing includes a first cylindrical port, a first connector and a second connector. The fluid interface provides fluid communication between the port and reservoir. An adapter secures a tube/needle valve from the supply reservoir to the port. The adapter includes a first member, a first protrusion and a second protrusion integrally formed as one structure. The first member defines an opening within which the needle valve is positioned. The first protrusion and second protrusion extend from the first member adjacent to the opening. The first protrusion engages the housing's first connector and the second protrusion engages the housing's second connector to attach the adapter to the housing. The valve mates to the port and a valve needle mates to the fluid interface.

Inkjet cartridge fill port adapter

A print cartridge is described which has an ink recharge port and valve structure to enable the print cartridge reservoir to be recharged with ink. A slideable, generally cylindrical ink valve extends through the print cartridge body and into the ink bag. The valve has a male connector portion at its end external to the print cartridge body. The valve is open when pushed into the print cartridge body and closed when pulled away from the print cartridge body. An ink refill system containing a supply of ink has a slideable valve with a female connector portion which is engageable with the male connector portion of the print cartridge valve. To recharge the print cartridge ink reservoir, the end of the print cartridge valve is inserted into the end of the ink refill system valve to create both a mechanical coupling and a fluid tight coupling between the two valves. A further force pushing the print cartridge against the ink refill system causes both valves to be pushed inside their respective ink reservoirs. This further insertion causes both valves to become open, thus creating an airtight fluid path between the ink refill system reservoir and the depleted print cartridge reservoir. When the valves are mechanically decoupled, the valves are automatically closed.

Inkjet print cartridge having valve connectable to an external ink

Disclosed is a method of determining imminent ink exhaustion in a thermal inkjet print cartridge based on the discovery that ink drop volume falls at a faster rate at high frequency firing rates than at low frequency firing rates as ink supply diminishes. The method includes warming the print cartridge printhead and ink to a predetermined temperature; then operating the print cartridge printhead at a first firing frequency to eject a volume of ink, said operating step including heating the ink and printhead, carrying away heat in the ejected volume of ink, and conveying a volume of cooler ink to the printhead to replace the ejected volume; and monitoring a first temperature change from the predetermined temperature. Then warming the same print cartridge printhead and ink to a predetermined temperature; operating the print cartridge printhead at a second firing frequency which is different than the first firing frequency to eject a volume of ink, said operating step including heating the ink and printhead, carrying away heat in the ejected volume of ink, and conveying a volume of cooler ink to the printhead to replace the ejected volume; and monitoring a second temperature change from the predetermined temperature. The first and second temperature changes are compared to indicate a low ink supply. The method is quickly and readily performed by a printer before printing or between printing intervals. The indication of low ink supply can be used to develop printer shutdown, or use of a reserve print cartridge, or an operator warning, or a combination of these tactics.

Ink level sensor for an inkjet print cartridge

Growing community of inventors

San Diego, CA, United States of America

Christopher J Shultz