Hewlett-packard Development Company, L.P.

Raymond Connolly

Boon Bing Ng

Patrick Leonard

Alexander N Govyadinov

Adam L Ghozeil

The present subject matter relates to printhead-integrated ink level sensor (PILS) system. In an example implementation, the PILS system includes a sense capacitor plate in a fluid sensing chamber to sense a level of fluid in the fluid sensing chamber. The fluid sensing chamber is in fluid communication with a fluid reservoir of the printhead to receive fluid from the fluid reservoir. The sense capacitor plate includes at least one slot. The PILS system further includes at least one central clearing resistor and at least one peripheral clearing resistor to clear the fluid sensing chamber of the fluid. The central clearing resistor is provided in the at least one slot of the sense capacitor plate. The at least one peripheral resistor is provided in the fluid sensing chamber surrounding the sense capacitor plate.

Printhead-integrated ink level sensor with central clearing resistor

A print head has a fluid slot and a sensing chamber having a first port connected to the fluid slot and a second port. The sensing chamber contains an ink level sensor. A circulation passage extends from the fluid slot and is fluidly coupled to the second port. A fluid pump circulates fluid through the circulation passage.

Print head sensing chamber circulation

A print head has an ink slot and a sensing chamber having a first port connected to the fluid slot and a second port. The sensing chamber contains an ink level sensor. A recirculation passage extends from the fluid slot and is fluidly coupled to the second port. A fluid pump circulates fluid through the recirculation passage.

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Leixlip, Ireland

Raymond Connolly