# US 7,611,220 B2 · Printhead and method for controlling print quality using printhead temperature

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- Number: US 7,611,220 B2
- Document ID: US7611220B2
- Status: Granted
- Kind: B2
- Application number: 11/743,659
- Filed: 2007-05-02
- Published: 2007-09-27
- Granted: 2009-11-03
- Earliest claimed: 1998-10-16
- Assignees: Silverbrook Research Pty Ltd
- Inventors: Kia Silverbrook
- Web page: https://patentgrep.com/patent/US7611220B2

## CPC

- B41J 2/04505: {aiming at correcting alignment}
- B41J 2/04516: {preventing formation of satellite drops}
- B41J 2/04518: {reducing costs}
- B41J 2/0452: {reducing demand in current or voltage}
- B41J 2/04528: {aiming at warming up the head}
- B41J 2/04541: {Specific driving circuit}
- B41J 2/04543: {Block driving}
- B41J 2/04553: {detecting ambient temperature}
- B41J 2/04563: {detecting head temperature; Ink temperature}
- B41J 2/04565: {detecting heater resistance}
- B41J 2/0457: {Power supply level being detected or varied}
- B41J 2/04571: {detecting viscosity}
- B41J 2/04585: {controlling heads based on thermal bent actuators}
- B41J 2/04588: {using a specific waveform}
- B41J 2/0459: {Height of the driving signal being adjusted}
- B41J 2/04591: {Width of the driving signal being adjusted}
- B41J 2/04593: {Dot-size modulation by changing the size of the drop}
- B41J 2/04596: {Non-ejecting pulses}
- B41J 2/04598: {Pre-pulse}
- B41J 2/14427: {Structure of ink jet print heads with thermal bend detached actuators}
- B41J 2/155: for line printing
- B41J 2/1623: {bonding and adhesion}
- B41J 2/1628: {dry etching}
- B41J 2/1629: {wet etching}
- B41J 2/1631: {photolithography}
- B41J 2/1632: {machining}
- B41J 2/1635: {dividing the wafer into individual chips}
- B41J 2/1639: {sacrificial molding}
- B41J 2/1642: {thin film formation by CVD [chemical vapor deposition]}
- B41J 2/1646: {thin film formation by sputtering}
- B41J 2/1648: {Production of print heads with thermal bend detached actuators}
- B41J 25/005: {for serial printing movements superimposed to character- or line-spacing movements}
- G06K 15/102: {using ink jet print heads}
- B41J 2002/14491: {Electrical connection}
- Y10T 29/49401: Fluid pattern dispersing device making, e.g., ink jet
- B41J: TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- G06K: GRAPHICAL DATA READING (image or video recognition or understanding G06V); PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A printhead and method of operation for controlling the print quality using temperature. A sensor senses the printhead temperature before printing begins. The controller compares it to a threshold temperature that represents desired ink drop characteristics. If the printhead temperature is below the threshold, it initiates heating elements and adjusts the heating elements until the threshold temperature has been reached.

## Claims

### Claim 1

A method of printing ink drops with a printhead over a print area, the method comprising the steps of:
receiving a temperature of the printhead before printing begins;
receiving resistivity feedback from the printhead, said resistivity feedback comprising information regarding a resistivity of individual heating elements in the printhead;
comparing the temperature with a predefined threshold temperature;
initiating heating elements if the temperature is below the threshold temperature;
turning off the heating elements when the threshold temperature of the printhead has been reached to produce desired characteristics in the ink drops; and,
pulsing the heating elements with electrical energy to impart sufficient kinetic energy to ink in the printhead to eject the ink drops with desired characteristics, wherein the temperature of the printhead and the resistivity feedback are together used to determine an amount and timing of electrical energy pulsed to each heating element.

### Claim 2 (depends on 1)

A method according to claim 1 wherein predefining the threshold temperature for the ink drops uses ink property data stored in a memory associated with the ink being supplied to the printhead.

### Claim 3 (depends on 2)

A method according to claim 2 wherein the data is stored in the form of a look up table.

### Claim 4 (depends on 1)

A method according to claim 1 wherein the threshold temperature relates to a predetermined size of the ink drops.

### Claim 5 (depends on 4)

A method according to claim 4 wherein the predetermined size of the ink drops is less than 2 pico liters.

### Claim 6 (depends on 4)

A method according to claim 4 wherein the predetermined size of the ink drops is between 1 pico liter and 0.7 pico liters.

### Claim 7 (depends on 1)

A method according to claim 1 wherein the threshold temperature relates to a predetermined ejection velocity of the ink drops.

### Claim 8 (depends on 7)

A method according to claim 7 wherein the predetermined ejection velocity is between 2 meters/sec and 4 meters/sec.

### Claim 9 (depends on 1)

A method according to claim 1 wherein the heating elements take less than 50 milliseconds to heat the printhead to the threshold temperature.

### Claim 10 (depends on 9)

A method according to claim 9 wherein the threshold temperature is about 30 degrees C. above ambient temperature.