# US 7,607,746 B2 · Temperature calibration for fluid ejection head

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- Number: US 7,607,746 B2
- Document ID: US7607746B2
- Status: Granted
- Kind: B2
- Application number: 11/955,329
- Filed: 2007-12-12
- Published: 2008-04-24
- Granted: 2009-10-27
- Earliest claimed: 2003-05-30
- Assignees: Hewlett-Packard Development Company, L.P.
- Inventors: Duane A. Koehler; Jefferson P. Ward; Huston W. Rice
- Web page: https://patentgrep.com/patent/US7607746B2

## CPC

- B41J 2/04508: {aiming at correcting other parameters}
- B41J 2/04563: {detecting head temperature; Ink temperature}
- B41J 2/0458: {controlling heads based on heating elements forming bubbles}
- B41J 2/072: {by thermal compensation}
- B41J 2/17546: {electronically}
- B41J 2/17553: {Outer structure}
- B41J 2/17559: {Cartridge manufacturing}
- B41J 29/393: Devices for controlling or analysing the entire machine {; Controlling or analysing mechanical parameters involving printing of test patterns}
- B41J 2202/17: Readable information on the head
- B41J: TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS

## Abstract

The present invention includes as one embodiment a method of ejecting a fluid onto a print media. The method includes providing an ejection head having a nozzle that is coupled to a temperature sensor and a memory device. The method further includes measuring an uncalibrated temperature of the ejection head with the temperature sensor, recalling a correction value from the memory device, applying the correction value to the uncalibrated temperature to generate a calibrated temperature, and ejecting fluid from the nozzle onto the print media when the calibrated temperature is within a predefined temperature range.

## Claims

### Claim 1

A fluid ejection head, comprising:
a fluid ejection nozzle that ejects a fluid in response to a firing signal;
a temperature sensor located to measure a temperature of the ejection head using a resistance of a temperature sensing resistor of the fluid ejection head, and to generate a temperature signal in response thereto; and
a memory device that stores a temperature correction value representing the difference between the temperature signal and an ideal resistance measured by a precision ohmeter; and
a controller configured to determine an offset value that equals a difference between the ideal resistance and an expected value of a process distribution mean, wherein the process distribution mean is an average value for printheads manufactured in a particular batch and using a particular process.

### Claim 2 (depends on 1)

The fluid ejection head of claim 1, further comprising a fluid conduit in fluid communication between the nozzle and a fluid supply.

### Claim 3 (depends on 2)

The fluid ejection head of claim 2, further comprising a fluid reservoir carrying the fluid supply.

### Claim 4 (depends on 1)

The fluid ejection head of claim 1, wherein the temperature correction value stored by the memory device is unique to the temperature sensor.

### Claim 5 (depends on 1)

The fluid ejection head of claim 1, wherein the fluid comprises an inkjet ink, the nozzle comprises a thermal inkjet nozzle, and the memory device comprises a register that also stores printhead identifying information.