# US 2019/0168514 A1 · System and methods for detecting malfunctioning nozzles in a digital printing press

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- Number: US 2019/0168514 A1
- Document ID: US20190168514A1
- Status: Published application
- Kind: A1
- Application number: 16/092,738
- Filed: 2017-04-06
- Published: 2019-06-06
- Earliest claimed: 2016-04-11
- Assignees: Advanced Vision Technology (A.V.T.) Ltd.
- Applicants: Advanced Vision Technology (A.V.T.) Ltd.
- Inventors: Chanan GAZALA
- Web page: https://patentgrep.com/patent/US20190168514A1

## CPC

- B41J 2/2142: {Detection of malfunctioning nozzles (generating single droplets or particles on demand by pressure, e.g. electromechanical transducers B41J2/045, B41J2/05; jet deflection sensors B41J2/125; for cleaning purposes B41J2/16579)}
- B41J 2/0451: {for detecting failure, e.g. clogging, malfunctioning actuator}
- B41J 2/04586: {controlling heads of a type not covered by groups B41J2/04575 - B41J2/04585, or of an undefined type}
- B41J 2/2146: {for line print heads}
- B41J: TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS

## Abstract

A method of identifying at least one malfunctioning nozzle in a digital printing press including a plurality of nozzles. The method includes the procedures of printing a design on a substrate, acquiring at least one image of the printed design and identifying at least one artifact in the acquired image. The method further includes the procedure of identifying the malfunctioning nozzle and classifying the at least one malfunctioning nozzle according to at least a portion of a combined pattern.

## Claims

### Claim 1

method of identifying at least one malfunctioning nozzle in a digital printing press, said digital printing press including a plurality of nozzles, the method comprising the procedures of:
printing a design on a substrate;
acquiring at least one image of the printed design;
identifying at least one artifact in the acquired image; and
identifying said malfunctioning nozzle and classifying said at least one malfunction nozzle according to at least a portion of a combined pattern by:
printing a combined pattern, said combined pattern including a respective combined color pattern for each color being printed, each said combined color pattern including a plurality of rows, each said row including a plurality of nozzle marks groups, each said nozzle marks group including nozzle marks associated with adjacent nozzles, each adjacent pair nozzle marks groups are spaced apart by a determined number of nozzles;
acquiring an image of said combined nozzle pattern;
detecting nozzle marks groups in each said combined pattern row of a respective combined color pattern in said combined pattern; and
identifying and classifying malfunctioning nozzles according to the nozzle sampling period, the expected width of said nozzle marks groups, a nozzle locator and the density of each nozzle.

### Claim 2

(canceled)

### Claim 3 (depends on 1)

The method according to claim 1, wherein, each said nozzle marks group further includes a respective at least one nozzle locator.

### Claim 4 (depends on 1)

The method according to claim 1, wherein a nozzle is classified as one of:
intact;
missing;
deviated;
inconsistent; and
redundant.

### Claim 5 (depends on 4)

The method according to claim 4, wherein a missing nozzle is identified by inspecting the width of a selected nozzle marks group and the spacing between the selected nozzle mark group and the is adjacent nozzle marks groups,
wherein a nozzle is identified as missing when the width of the nozzle mark group is smaller than expected and the spacing between the selected nozzle marks group and one at least one of the adjacent nozzle marks groups is larger than expected.

### Claim 6 (depends on 5)

The method according to claim 5, wherein a deviated nozzle is identified by identifying a missing nozzle and an additional mark between nozzle marks group.

### Claim 7 (depends on 4)

The method according to claim 4, wherein an inconsistent nozzle is identified according to the edges of the segment respective of the nozzle mark group,
wherein an inconsistent nozzle exhibits a non-uniform edge of the segment respective of the nozzle mark group.

### Claim 8 (depends on 4)

The method according to claim 4, where a redundant nozzle is identified when an additional nozzle mark is detected and a missing nozzle is not detected.

### Claim 9 (depends on 1)

The method according to claim 1, wherein each nozzle locator exhibits a pre-defined shape printed by a predetermined respective set of nozzles.

### Claim 10 (depends on 1)

The method according to claim 1, wherein said density of each nozzle is determined by employing super-resolution techniques.