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US 10,308,035 B2Granted
Fluid level sensor and related methods
AssigneeHewlett-Packard Development Company, L.P.
InventorsAndrew L. Van Brocklin, Paul A. Liebert, Adam L. Ghozeil, Scott A. Linn
Life of this patent
Estimating the term…
Abstract
In an embodiment, a fluid level sensor includes a sensor plate and a current source. The fluid level sensor also includes an algorithm to bias the current source such that current applied to the sensor plate induces a maximum difference in response voltage between a dry sensor plate condition and a wet sensor plate condition.
Claims20
A fluid cartridge comprising:
- a nozzle;
- a fluid channel;
- a sensor plate on a floor of the channel;
- a current source coupled to the sensor plate to induce a voltage response across the sensor plate;
- a sensor circuit to determine the voltage response of the sensor plate to the current source, the voltage response indicating to what extent the sensor plate is in contact with fluid and with air;
- and
- an electronic controller to determine a bias for the current source such that the induced voltage response across the sensor plate has a maximum variation between wet and dry sensor plate conditions;
- wherein the electronic controller is to output a signal indicative of a fluid level based on the voltage response of the sensor plate.
5 more elements
A fluid cartridge comprising:
- a nozzle;
- a fluid channel;
- a sensor plate on a floor of the channel;
- a current source coupled to the sensor plate to induce a voltage response across the sensor plate;
- a sensor circuit to determine the voltage response of the sensor plate to the current source, the voltage response indicating to what extent the sensor plate is in contact with fluid and with air;
- and
- an electronic controller to determine a bias for the current source such that the induced voltage response across the sensor plate has a maximum variation between wet and dry sensor plate conditions;
- wherein the electronic controller is to output a signal indicative of a fluid level based on the voltage response of the sensor plate;
- and
- further comprising a register operated by the electronic controller, the register to provide input to a Digital-to-Analog Converter (DAC) and Sample & Hold Circuit to provide a bias to the current source.
7 more elements
A fluid cartridge comprising:
- a nozzle;
- a fluid channel;
- a sensor plate on a floor of the channel;
- a current source coupled to the sensor plate to induce a voltage response across the sensor plate;
- a sensor circuit to determine the voltage response of the sensor plate to the current source, the voltage response indicating to what extent the sensor plate is in contact with fluid and with air;
- and
- an electronic controller to determine a bias for the current source such that the induced voltage response across the sensor plate has a maximum variation between wet and dry sensor plate conditions;
- wherein the electronic controller is to output a signal indicative of a fluid level based on the voltage response of the sensor plate;
- and
- wherein the sensor plate is located in the fluid channel where an increase in backpressure associated with a depleted ink supply will pull an ink meniscus far enough back into the fluid channel that the sensor plate is exposed to air drawn through the nozzle.
7 more elements
Dependencies are inferred from the claim text.