Hewlett-packard Development Company, L.p.

Andrew B Levy

Mark A Devries

Jeremy Bunn

Greg K Justice

Chris Arnold

Dan L Collier

Charles Newby

Ricardo G Diaz

An ink delivery system includes a plurality of ink supplies, an air pressure source to generate ink pressure for each ink supply, an ink valve associated with each ink supply, where each ink valve is configured to prevent a reverse flow of ink from a pen to the associated ink supply, and each ink valve has a switch configured to provide an open signal when the ink valve is open, and a controller configured to determine one of a normal ink condition, an out of ink condition or a system pressure problem based on receiving the open signals and to regulate the pressure source according to the determination.

Ink delivery system

In one embodiment, an imaging device includes an ink density information gathering procedure. An ink use calculation procedure receives input from the ink density information gathering procedure, allowing the amount of ink used to be calculated. A job cost procedure calculates a print job value based on the amount of ink used.

Pay-per-use printing

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West Linn, OR, United States of America

Andrew B Levy