# US 9,751,302 B1 · Mitigating effects of crosstalk in an inkjet head

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- Number: US 9,751,302 B1
- Document ID: US9751302B1
- Status: Granted
- Kind: B1
- Application number: 15/058,085
- Filed: 2016-03-01
- Published: 2017-09-07
- Granted: 2017-09-05
- Earliest claimed: 2016-03-01
- Assignees: Ricoh Company, Ltd.
- Applicants: Hiroshi Nishimura; Shogo Nobumori
- Inventors: Hiroshi Nishimura; Shogo Nobumori
- Web page: https://patentgrep.com/patent/US9751302B1

## CPC

- B41J 2/04541: {Specific driving circuit}
- B41J 2/04525: {reducing occurrence of cross talk}
- B41J 2/04581: {controlling heads based on piezoelectric elements}
- B41J 2/04586: {controlling heads of a type not covered by groups B41J2/04575 - B41J2/04585, or of an undefined type}
- B41J 2/04588: {using a specific waveform}
- B41J 2/0459: {Height of the driving signal being adjusted}
- B41J 2/04596: {Non-ejecting pulses}
- B41J 2/14233: {of film type, deformed by bending and disposed on a diaphragm}
- B41J 2002/14403: {including a filter}
- B41J: TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS

## Abstract

Systems and methods of mitigating the effects of crosstalk in an inkjet head. An inkjet head has ink channels that jet droplets of a liquid material using piezoelectric actuators. Drive waveforms provided to the piezoelectric actuators include jetting pulses that cause activation of the piezoelectric actuators to jet the droplets from the ink channels. When crosstalk exists between the ink channels of the inkjet head due to the piezoelectric actuators, the amplitude of the jetting pulses are modified to mitigate the crosstalk between the ink channels.

## Claims

### Claim 1

A system comprising:
an inkjet head comprising a plurality of ink channels in a row that jet droplets of a liquid material onto a medium using piezoelectric actuators;
a jetting pulse generator that selectively provides drive waveforms to the piezoelectric actuators in the row, wherein the drive waveforms include jetting pulses that cause activation of the piezoelectric actuators to jet the droplets from the ink channels; and
a compensation controller that identifies a crosstalk value indicating a type of crosstalk between the ink channels in the row for the inkjet head, and modifies the drive waveforms output by the jetting pulse generator and selectively provided to the piezoelectric actuators to increase an amplitude of each of the jetting pulses or decrease the amplitude of each of the jetting pulses based on the type of crosstalk.

### Claim 2 (depends on 1)

The system of claim 1 wherein:
the compensation controller increases the amplitude of each of the jetting pulses responsive to negative crosstalk between the ink channels.

### Claim 3 (depends on 2)

The system of claim 2 wherein:
the compensation controller adjusts a leading edge of the jetting pulses to exceed a target jetting voltage.

### Claim 4 (depends on 1)

The system of claim 1 wherein:
the compensation controller decreases the amplitude of each of the jetting pulses responsive to positive crosstalk between the ink channels.

### Claim 5 (depends on 4)

The system of claim 4 wherein:
the compensation controller adjusts a leading edge of the jetting pulses below a target jetting voltage.

### Claim 6 (depends on 1)

The system of claim 1 further comprising:
a droplet analyzer;
the jetting pulse generator provides the drive waveforms to the piezoelectric actuators in adjacent ink channels; and
the droplet analyzer measures jetting characteristics of the droplets jetted from the adjacent ink channels, and compares the jetting characteristics of the droplets to target characteristics to identify the type of crosstalk.

### Claim 7 (depends on 6)

The system of claim 6 wherein:
the jetting characteristics comprise a velocity of the droplets.

### Claim 8 (depends on 6)

The system of claim 6 wherein:
the jetting characteristics comprise a mass of the droplets.

### Claim 9

A method of mitigating crosstalk in an inkjet head, wherein the inkjet head includes a plurality of ink channels in a row that jet droplets of a liquid material onto a medium using piezoelectric actuators, the method comprising:
selectively providing drive waveforms to the piezoelectric actuators in the row with a jetting pulse generator, wherein the drive waveforms include jetting pulses that cause activation of the piezoelectric actuators to jet the droplets from the ink channels;
identifying a crosstalk value indicating a type of crosstalk between the ink channels in the row for the inkjet head; and
modifying the drive waveforms output by the jetting pulse generator and selectively provided to the piezoelectric actuators to increase an amplitude of each of the jetting pulses or decrease the amplitude of each of the jetting pulses based on the type of crosstalk.

### Claim 10 (depends on 9)

The method of claim 9 wherein modifying the drive waveforms comprises:
increasing the amplitude of each of the jetting pulses responsive to negative crosstalk between the ink channels.

### Claim 11 (depends on 10)

The method of claim 10 wherein increasing the amplitude of the jetting pulses comprises:
adjusting a leading edge of the jetting pulses to exceed a target jetting voltage.

### Claim 12 (depends on 9)

The method of claim 9 wherein modifying the drive waveforms comprises:
decreasing the amplitude of each of the jetting pulses responsive to positive crosstalk between the ink channels.

### Claim 13 (depends on 12)

The method of claim 12 wherein decreasing the amplitude of the jetting pulses comprises:
adjusting a leading edge of the jetting pulses below a target jetting voltage.

### Claim 14 (depends on 9)

The method of claim 9 further comprising:
identifying the crosstalk between the ink channels in the inkjet head by:
providing the drive waveforms to the piezoelectric actuators in adjacent ink channels;
measuring jetting characteristics of the droplets jetted from the adjacent ink channels; and
comparing the jetting characteristics of the droplets to target characteristics to identify the type of crosstalk.

### Claim 15 (depends on 14)

The method of claim 14 wherein:
the jetting characteristics comprise a velocity of the droplets.

### Claim 16 (depends on 14)

The method of claim 14 wherein:
the jetting characteristics comprise a mass of the droplets.

### Claim 17

A system comprising:
a drive circuit that connects to an inkjet head having ink channels in a row that jet droplets of a liquid material onto a medium using piezoelectric actuators;
the drive circuit selectively provides drive waveforms to the piezoelectric actuators, wherein the drive waveforms include jetting pulses that cause activation of the piezoelectric actuators to jet the droplets from the ink channels; and
the drive circuit identifies a crosstalk value indicating a type of crosstalk between the ink channels in the row for the inkjet head, and modifies the drive waveforms selectively provided to the piezoelectric actuators to increase an amplitude of each of the jetting pulses or decrease the amplitude of each of the jetting pulses based on the type of crosstalk.

### Claim 18 (depends on 17)

The system of claim 17 wherein:
the drive circuit increases the amplitude of the jetting pulses responsive to negative crosstalk between the ink channels.

### Claim 19 (depends on 17)

The system of claim 17 wherein:
the drive circuit decreases the amplitude of the jetting pulses responsive to positive crosstalk between the ink channels.