Hewlett-packard Development Company, L.P.

Berkeley Fisher

James Michael Gardner

Daryl E Anderson

Michael W Cumbie

Scott A Linn

Andrew Koll

A die may include a plurality of fluid pumps, at least one strain gauge sensor to sense a strain in the die, and at least one temperature sensor to sense the temperature of the die to compensate for a temperature component of the sensed strain.

Dies including strain gauge sensors and temperature sensors

In some examples, a fluid dispensing device component includes an input to receive a control signal from the fluid dispensing system, the control signal for activating the fluidic actuators of the fluid dispensing device during a fluidic operation mode. The fluid dispensing device component includes a nonvolatile memory, and a controller to, during a memory write mode, write a first portion of the nonvolatile memory to a first programmed level responsive to the control signal being activated for a first time duration, and write a second portion of the nonvolatile memory to a second programmed level responsive to the control signal being activated for a second time duration different from the first time duration, the second programmed level being different from the first programmed level.

Writing a nonvolatile memory to programmed levels

A fluid ejection system includes a fluid ejection die and a controller. The fluid ejection die includes a plurality of nozzles to eject fluid drops and a plurality of strain gauge sensors to sense strain within the fluid ejection die. The controller is to receive the sensed strain from each strain gauge sensor to determine a status of the fluid ejection die.

Fluid ejection dies including strain gauge sensors

A fluid ejection system includes a fluid ejection die, a service station assembly, and a controller. The fluid ejection die includes at least one strain gauge sensor to sense strain. The service station assembly is to service the fluid ejection die. The controller is to receive the sensed strain from the at least one strain gauge sensor during servicing of the fluid ejection die and adjust or stop servicing of the fluid ejection die in response to the sensed strain exceeding a servicing threshold.

A method of detecting a level of printable fluid in a container includes, with at least one sensing location on a die in thermal contact with the printable fluid in the container, sensing a voltage of a capacitor over time as current from the capacitor leaks through a field effect transistor (FET). The FET and capacitor are associated with the sensing location. The method may further include, based on the voltage of the capacitor over time and a threshold voltage, determining whether the printable fluid is present at the at least one sensing location.

Detecting a level of printable fluid in a container

A fluid ejection die includes a plurality of nozzles to eject fluid drops and a plurality of strain gauge sensors to sense strain. Each strain gauge sensor corresponds to a nozzle and passes the sensed strain to a controller to determine the health of the nozzle based on the sensed strain.

An example printing cartridge includes a sensing die including a plurality of sensing locations in thermal contact with a fluid container, an on-die controller to select a sensing location of the plurality of sensing locations to activate and to provide a variable threshold voltage, and a voltage comparator to compare a sensed voltage generated at a selected sensing location to the variable threshold voltage, and output time-based information based on the comparison, the time-based information representative of whether a fluid is present at a fluid level associated with the selected sensing location.

Detecting fluid levels using a variable threshold voltage

An example printing cartridge includes a fluid container, a plurality of sensing locations in thermal contact with the fluid container, a voltage comparator to output time-based information based on a comparison of a sensed voltage generated at a selected sensing location of the plurality of sensing locations to a threshold voltage, the time-based information representative of whether a fluid is present at a fluid level associated with the selected sensing location, and a counter to convert the time-based information to a digital code based on a number of clock cycles.

Detecting fluid levels using a counter

A fluidic die may include a substrate having a flexible region opposite a fluid supply passage within the substrate, a nozzle supported by the substrate proximate the flexible region and a strain sensor on the flexible region of the substrate. The strain sensor may sense strain during flexing of the flexible region to sense fluid back pressure changes.

Fluid back pressure sensing with a strain sensor

An example printing cartridge includes a fluid container, a plurality of capacitor plates to detect fluid in the fluid container, each of the capacitor plates associated with a respective fluid level, and a shift register to capture fluid level information from the plurality of capacitor plates.

Printing apparatus and methods for detecting fluid levels

A die includes a plurality of fluid actuation devices and at least one strain gauge sensor to sense strain. The die also includes at least one temperature sensor to sense the temperature of the die to compensate for a temperature component of the sensed strain.

An example printing cartridge includes a fluid container, a sensing die including a plurality of sensing locations in thermal contact with the fluid container, and a voltage comparator to output time-based information by comparing a sensed voltage generated at a selected sensing location of the plurality of sensing locations to a threshold voltage, the time-based information representative of whether a fluid is present at the sensing location.

Detecting fluid levels using a voltage comparator

In one example, a fluid level sensor includes control logic, and an array of sensing locations to detect a level of fluid in a container. The array of sensing locations include a number of memory cells located at a number of sensing locations in the array of sensing locations, a word line coupled to the memory cells, a bit line coupled to the memory cells, and a pre-charge circuit coupled to the word line and the bit line. The control logic instructs a number FETs coupled to a bit line to disconnect from a number of the memory cells, and power up the memory cells to cause the memory cells to take a first state or a second state. The control logic outputs the state of the memory cells to a processing device. The state of the memory cells defines the level of the fluid in the container.

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