# US 10,370,550 B2 · Ink set and duplex printing method

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- Number: US 10,370,550 B2
- Document ID: US10370550B2
- Status: Granted
- Kind: B2
- Application number: 16/038,360
- Filed: 2018-07-18
- Published: 2018-11-08
- Granted: 2019-08-06
- Earliest claimed: 2015-06-26
- Assignees: Seiko Epson Corporation
- Applicants: Seiko Epson Corporation
- Inventors: Soichi Yamazaki
- Web page: https://patentgrep.com/patent/US10370550B2

## CPC

- C09D 11/40: Ink-sets specially adapted for multi-colour inkjet printing
- C09D 11/322: Pigment inks
- C09D 11/38: characterised by non-macromolecular additives other than solvents, pigments or dyes
- C09D: COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR (cosmetics A61K; processes for applying liquids or other fluent materials to surfaces, in general, B05D; staining wood B27K5/02; glazes or vitreous enamels C03C; natural resins, French polish, drying-oils, driers, turpentine, per se, C09F; polishing compositions other than French polish, ski waxes C09G; adhesives or use of materials as adhesives C09J; materials for sealing or packing joints or covers C09K3/10; materials for stopping leaks C09K3/12; processes for the electrolytic or electrophoretic production of coatings C25D)

## Abstract

According to the invention, there is provided an ink set which contains at least one ink selected from a group of a black pigment ink, a self-dispersing color pigment ink, and a resin-dispersion color pigment ink. The moisture quantity of the black pigment ink is from 68 mass % to 75 mass %. The moisture quantity of the self-dispersing color pigment ink is from 62 mass % to 72 mass %. The moisture quantity of the resin-dispersion color pigment ink is from 68 mass % to 75 mass %.

## Claims

### Claim 1

A duplex printing method of performing duplex printing by using an ink jet recording apparatus, wherein
the ink jet recording apparatus includes an ink set and a sheet transporting mechanism,
the ink set contains at least one selected from a group of a black pigment ink, a self-dispersing color pigment ink, and a resin-dispersion color pigment ink,
a moisture quantity of the black pigment ink is from 68 mass % to 75 mass %,
a moisture quantity of the self-dispersing color pigment ink is from 62 mass % to 72 mass %,
a moisture quantity of the resin-dispersion color pigment ink is from 68 mass % to 75 mass %,
each of the black pigment ink, the self-dispersing color pigment ink, and the resin-dispersion color pigment ink further contains an alkylene glycol monoalkyl ether in an amount that ranges between 0.5 mass % to 6 mass %,
each of the black pigment ink, the self-dispersing color pigment ink, and the resin-dispersion color pigment ink further contains trimethylglycine,
each of the black pigment ink, the self-dispersing color pigment ink, and the resin-dispersion color pigment ink contains three or more types of acetylene glycol-based surfactants selected from a group of acetylene glycol and an ethylene oxide adduct of acetylene glycol, and the total content of the acetylene glycol-based surfactants is from 0.1 mass % to 3 mass % with respect to the total mass of each of the black pigment ink, the self-dispersing color pigment ink, and the resin-dispersion color pigment ink, and
in the sheet transporting mechanism, a period from when printing on a front surface is started, until printing on a back surface is started is within three seconds.

### Claim 2 (depends on 1)

The duplex printing method according to claim 1, wherein
a duplex printing speed (page/minute) in printing a solid image on the entirety of a surface of plain paper is from 30% to 100% of a simplex printing speed.

### Claim 3 (depends on 1)

The duplex printing method according to claim 1, wherein
the black pigment ink is formed from a self-dispersing pigment.

### Claim 4 (depends on 1)

The duplex printing method according to claim 1, wherein
the viscosity of each of the black pigment ink, the self-dispersing color pigment ink, and the resin-dispersion color pigment ink is from 2.0 mm2/s to 4.0 mm2/s.

### Claim 5 (depends on 1)

The duplex printing method according to claim 1, wherein
each of the black pigment ink, the self-dispersing color pigment ink, and the resin-dispersion color pigment ink further contains 1,2-alkane diol.