# US 10,870,273 B2 · Dies including strain gauge sensors and temperature sensors

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- Number: US 10,870,273 B2
- Document ID: US10870273B2
- Status: Granted
- Kind: B2
- Application number: 16/619,172
- Filed: 2017-07-18
- Published: 2020-05-28
- Granted: 2020-12-22
- Earliest claimed: 2017-07-18
- Assignees: Hewlett-Packard Development Company, L.P.
- Applicants: Hewlett-Packard Development Company, L.P.
- Inventors: James M Gardner; Berkeley Fisher; Daryl E Anderson
- Web page: https://patentgrep.com/patent/US10870273B2

## CPC

- B41J 2/04563: {detecting head temperature; Ink temperature}
- B41J 2/0458: {controlling heads based on heating elements forming bubbles}
- B41J 2/04508: {aiming at correcting other parameters}
- B41J 2/04586: {controlling heads of a type not covered by groups B41J2/04575 - B41J2/04585, or of an undefined type}
- B41J 2/14153: {Structures including a sensor}
- B41J 2/175: Ink supply systems {; Circuit parts therefor}
- B41J 29/02: Framework
- B41J 29/393: Devices for controlling or analysing the entire machine {; Controlling or analysing mechanical parameters involving printing of test patterns}
- G01L 1/18: using properties of piezo-resistive materials, i.e. materials of which the ohmic resistance varies according to changes in magnitude or direction of force applied to the material
- G01L 1/22: using resistance strain gauges
- B41J: TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- G01L: MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE (weighing G01G)

## Abstract

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.

## Claims

### Claim 1

A die comprising:
a plurality of fluid actuation devices;
at least one strain gauge sensor to sense a strain within 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.

### Claim 2 (depends on 1)

The die of claim 1, wherein the at least one strain gauge sensor comprises a piezoresistive sensor element.

### Claim 3 (depends on 1)

The die of claim 1, wherein the at least one strain gauge sensor comprises three piezoresistive sensor elements in a rosette configuration.

### Claim 4 (depends on 1)

The die of claim 1, wherein the at least one temperature sensor comprises a further strain gauge sensor.

### Claim 5 (depends on 4)

The die of claim 4, wherein the further strain gauge sensor comprises four piezoresistive sensor elements in a Wheatstone bridge configuration co-located with the at least one strain gauge sensor, and
wherein the sensed temperature is based on the difference in the sensed strain between the at least one strain gauge sensor and the further strain gauge sensor.

### Claim 6 (depends on 4)

The die of claim 4, wherein the at least one temperature sensor comprises three piezoresistive sensor elements in a rosette configuration at a location of the fluid ejection die having substantially no stress.

### Claim 7

A fluid ejection system comprising:
a fluid ejection die comprising a plurality of actuation devices to eject fluid drops, a plurality of strain gauge sensors to sense a strain within the fluid ejection die, and a plurality of temperature sensors to sense temperature within the fluid ejection die; and
a controller to receive the sensed strain from each strain gauge sensor and the sensed temperature from each temperature sensor and provide a temperature compensated strain for each sensed strain based on the sensed temperatures.

### Claim 8 (depends on 7)

The fluid ejection system of claim 7, wherein each strain gauge sensor comprises three piezoresistive sensor elements in a rosette configuration.

### Claim 9 (depends on 7)

The fluid ejection system of claim 7, wherein the fluid ejection die comprises one temperature sensor for each strain gauge sensor.

### Claim 10 (depends on 7)

The fluid ejection system of claim 7, wherein the fluid ejection die comprises more strain gauge sensors than temperature sensors.

### Claim 11 (depends on 7)

The fluid ejection system of claim 7, wherein each strain gauge sensor is co-located with a temperature sensor.

### Claim 12

A method for maintaining a fluid ejection system, the method comprising:
sensing a strain at a plurality of locations within a fluid ejection die via strain gauge sensors integrated within the fluid ejection die;
sensing the temperature at the plurality of locations within the fluid ejection die via temperature sensors integrated within the fluid ejection die; and
compensating the sensed strain from each strain gauge sensor based on the sensed temperatures.

### Claim 13 (depends on 12)

The method of claim 12, wherein sensing the strain comprises sensing the strain in three directions at each of the plurality of locations.

### Claim 14 (depends on 12)

The method of claim 12, wherein sensing the temperature comprises sensing the temperature at each location within the fluid ejection die via a temperature sensor corresponding to each strain gauge sensor.

### Claim 15 (depends on 12)

The method of claim 12, further comprising:
interpolating the temperature at a portion of the plurality of locations based on sensed temperatures from at least two temperature sensors.