Hewlett-packard Development Company, L.P.

Patrick Leonard

Ning Ge

Adam L Ghozeil

Boon Bing Ng

Raymond Connolly

Alexander N Govyadinov

Joseph M Torgerson

Hang Ru Goy

Shane O'Brien

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

In some examples, a cartridge includes a printhead comprising a fluid feed slot, a fluid chamber formed between a nozzle layer and a passivation layer, the fluid chamber fluidically coupling the fluid feed slot and a nozzle of the nozzle layer, and a printhead-integrated sensor to sense a property of a fluid in the fluid chamber, the sensor including a ground electrode exposed to the fluid chamber through an opening in the passivation layer.

Cartridges comprising sensors including ground electrodes exposed to fluid chambers

A fluid ejection device including a printhead die having a plurality of layers, including a single metal layer, and having an integrated ink level sensor. The ink level sensor includes an ink chamber above the metal layer, a metal plate of a sense capacitor disposed in the metal layer, and a clearing resistor circuit disposed in the metal layer including four clearing resistors arranged in a surround-4 configuration about the metal plate and electrically connected in parallel between a voltage potential and ground, wherein adjacent ends of at least two clearing resistors are not directly connected to one another so as to leave a gap between the adjacent ends in the metal layer. A metal lead in the metal layer extends through the gap to the metal plate.

Fluid ejection device with printhead ink level sensor

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.

An example provides a fluid ejection device including a fluid feed slot, a fluid chamber between a nozzle layer and a passivation layer, and a printhead-integrated sensor to sense a property of a fluid in the fluid chamber. The sensor may include a ground electrode exposed to the fluid chamber through a via in the passivation layer.

Fluid ejection device with ground electrode exposed to fluid chamber

In an embodiment, a fluid ejection device includes an ink slot formed in a printhead die. The fluid ejection device also includes a printhead-integrated ink level sensor (PILS) to sense an ink level of a chamber in fluid communication with the slot, and a clearing resistor circuit disposed within the chamber to clear the chamber of ink.

Fluid ejection device with integrated ink level sensor

In an embodiment, a fluid ejection device includes a fluid feed slot formed in a printhead die and a plurality of printhead-integrated ink level sensors (PILS). A fluid ejection device may include a first PILS to sense an ink level of a first chamber in fluid communication with the fluid feed slot, the first PILS to detect an empty ink level of the first chamber when the fluid ejection device is at a first ink level state, and a second PILS to sense an ink level of a second chamber in fluid communication with the fluid feed slot, the second PILS to detect an empty ink level of the second chamber when the fluid ejection device is at a second ink level state, different than the first ink level state.

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Leixlip, Ireland

Patrick Leonard