# US 11,445,088 B2 · High-speed single-pass printing using combined dither pattern

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- Number: US 11,445,088 B2
- Document ID: US11445088B2
- Status: Granted
- Kind: B2
- Application number: 17/206,753
- Filed: 2021-03-19
- Published: 2021-09-23
- Granted: 2022-09-13
- Earliest claimed: 2020-03-20
- Assignees: Memjet Technology Limited
- Applicants: Memjet Technology Limited
- Inventors: Rodney Hardy; James Lawrence
- Web page: https://patentgrep.com/patent/US11445088B2

## CPC

- B41J 2/2146: {for line print heads}
- H04N 1/405: Halftoning, i.e. converting the picture signal of a continuous-tone original into a corresponding signal showing only two levels
- B41J 2/2132: {Print quality control characterised by dot disposition, e.g. for reducing white stripes or banding (methods for local corrections by dot omission, image edge enhancement, or multi-pass mask selection G06K15/102; colour conversion H04N1/40)}
- B41J 2/515: line printer type
- G06K 15/027: {Test patterns and calibration (arrangements for controlling or analysing printing mechanisms of typewriters or selective printing units B41J29/393 takes precedence; colour correction using test pattern analysis in general H04N1/6033)}
- G06K 15/102: {using ink jet print heads}
- G06K 15/105: {Multipass or interlaced printing}
- G06K 15/1876: {Decreasing spatial resolution; Dithering}
- G06K 15/1877: {with provisions for treating some of the print data differently}
- G06K 15/1881: {Halftoning (halftoning of still images in general H04N1/405, H04N1/52)}
- H04N 1/52: Circuits or arrangements for halftone screening
- B41J 2202/21: Line printing
- B41M 5/50: Recording sheets characterised by the coating used to improve ink, dye or pigment receptivity, e.g. for ink-jet or thermal dye transfer recording {(printing on organic plastics using a printer's form B41M1/30; printing on pre-treated paper with a printer's form B41M1/36)}
- B41J: TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION
- G06K: GRAPHICAL DATA READING (image or video recognition or understanding G06V); PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
- B41M: PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING, (correction of typographical errors B41J; processes for applying transfer pictures or the like B44C1/16; fluid media for correction of typographical errors by coating C09D10/00; printing textiles D06P)

## Abstract

A method of processing a contone image for single-pass printing uses a printing system having first and second aligned printheads supplied with a same ink. The method includes the steps of: providing the contone image at a first resolution in a printing direction; dithering the contone image using a combined dither pattern to provide a full halftone image at the first resolution; dividing the full halftone image into first and second halftone images at a second resolution in the printing direction, the second resolution being less than the first resolution; and sending the first and second halftone images to respective first and second printheads for printing. The combined dither pattern is a combination of a first dither pattern for the first printhead and a second dither pattern for the second printhead, the first dither pattern being different than the second dither pattern.

## Claims

### Claim 1

A method of processing a contone image for single-pass printing using a printing system comprising at least first and second aligned printheads supplied with a same ink, the second printhead being downstream of the first printhead, the method comprising the steps of:
providing the contone image for one ink channel at a first resolution in a printing direction;
selecting a dither pattern from the group either one of: (a) a combined dither pattern comprising a combination of a first dither pattern for the first printhead and a second dither pattern for the second printhead, the first dither pattern being different than the second dither pattern; or (b) a third dither pattern for both the first and second printheads;
dithering the contone image using the selected dither pattern to provide a full halftone image at the first resolution;
dividing the full halftone image into at least first and second halftone images at a second resolution in the printing direction, the second resolution being less than the first resolution; and
sending the first and second halftone images to respective first and second printheads for printing,
wherein the selection of the dither pattern from either (a) the combined dither pattern, or (b) the third dither pattern is based on relative printhead alignment between the first and second printheads.

### Claim 2 (depends on 1)

The method of claim 1, wherein the relative printhead alignment is based on qualitative print quality feedback from a user.

### Claim 3 (depends on 1)

The method of claim 1, wherein the relative printhead alignment is based on a quantitative alignment measurement.

### Claim 4 (depends on 1)

The method of claim 1, wherein the third dither pattern is the same or different than the first dither pattern or the second dither pattern.

### Claim 5 (depends on 1)

The method of claim 1, wherein the first and second halftone images contain respective first and second sets of lines of the full halftone image.

### Claim 6 (depends on 1)

The method of claim 1, wherein the printing system comprises n aligned printheads supplied with the same ink and the second resolution is 1/n of the first resolution in the printing direction.

### Claim 7 (depends on 1)

The method of claim 1, wherein the printing system comprises two aligned printheads supplied with the same ink and the second resolution is half of the first resolution.