# US 8,770,692 B2 · Crosstalk reduction in piezo printhead

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- Number: US 8,770,692 B2
- Document ID: US8770692B2
- Status: Granted
- Kind: B2
- Application number: 13/258,758
- Filed: 2010-01-29
- Published: 2012-01-26
- Granted: 2014-07-08
- Earliest claimed: 2010-01-29
- Assignees: Hewlett-Packard Development Company, L.P.
- Applicants: Andrew L. Van Brocklin; Neel Banerjee
- Inventors: Andrew L. Van Brocklin; Neel Banerjee
- Web page: https://patentgrep.com/patent/US8770692B2

## CPC

- B41J 2/04581: {controlling heads based on piezoelectric elements}
- B41J 2/04525: {reducing occurrence of cross talk}
- B41J 2/04541: {Specific driving circuit}
- B41J 2/04588: {using a specific waveform}
- B41J: TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS

## Abstract

Crosstalk in a piezo printhead is reduced by storing a coefficient that expresses an amount of crosstalk between a first nozzle and an adjacent nozzle. A drive waveform voltage is pre-biased using the coefficient, and the pre-biased waveform is applied to a piezoelectric material of the first nozzle.

## Claims

### Claim 1

A method to reduce crosstalk in a piezo printhead comprising:
storing a coefficient that expresses an amount of crosstalk between a first nozzle and an adjacent nozzle;
pre-biasing a drive waveform voltage using the coefficient by summing to the drive waveform voltage, a scaled copy of a second drive waveform voltage for the adjacent nozzle; and
applying the pre-biased drive waveform voltage to a piezoelectric material of the first nozzle.

### Claim 2 (depends on 1)

A method as recited in claim 1, wherein summing comprises:
multiplying the coefficient with the second drive waveform voltage to form a product; and
summing the product and the drive waveform voltage.

### Claim 3 (depends on 1)

A method as recited in claim 1, wherein the scaled copy is a product of the coefficient and the second drive waveform voltage for the adjacent nozzle.

### Claim 4 (depends on 1)

A method as recited in claim 1, wherein pre-biasing comprises:
multiplying the coefficient squared with the drive waveform voltage to form a second order compensation; and
summing to the drive waveform voltage, the scaled copy and the second order compensation.

### Claim 5

A printhead assembly comprising a crosstalk reduction circuit to transform a voltage drive waveform of a first nozzle to compensate for crosstalk from an adjacent nozzle wherein the crosstalk reduction circuit comprises:
a storage element to store a coefficient that expresses an amount of crosstalk between the first nozzle and the adjacent nozzle;
a multiplier to generate a scaled copy of a second drive waveform voltage for the adjacent nozzle; and
a summing element to sum the scaled copy to a first drive waveform voltage associated with the first nozzle.

### Claim 6 (depends on 5)

A printhead assembly as recited in claim 5, further comprising:
a second multiplier to generate a compensation product from the compensation product and the coefficient, wherein the summing element is configured to sum the scaled copy and the second compensation product to the first drive waveform.

### Claim 7 (depends on 5)

A printhead assembly as recited in claim 5 wherein the crosstalk reduction circuit is fabricated on a circuit board of the printhead assembly and coupled to a printhead die.

### Claim 8 (depends on 5)

A printhead assembly as recited in claim 5 wherein the crosstalk reduction circuit is integrated onto a printhead die of the printhead assembly.

### Claim 9 (depends on 5)

A printhead assembly as recited in claim 5 wherein the multiplier is to generate the scaled copy by multiplying the coefficient with the second drive waveform voltage to form a product.