# US 8,770,735 B2 · Inkjet recording ink and ink cartridge

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- Number: US 8,770,735 B2
- Document ID: US8770735B2
- Status: Granted
- Kind: B2
- Application number: 13/391,905
- Filed: 2010-09-06
- Published: 2012-06-21
- Granted: 2014-07-08
- Earliest claimed: 2009-09-09
- Assignees: Ricoh Company, Ltd.
- Applicants: Minoru Hakiri; Shin Hasegawa; Hiroyuki Fushimi; Mitsuru Naruse; Naoya Morohoshi
- Inventors: Minoru Hakiri; Shin Hasegawa; Hiroyuki Fushimi; Mitsuru Naruse; Naoya Morohoshi
- Web page: https://patentgrep.com/patent/US8770735B2

## CPC

- B41J 2/2107: {characterised by the ink properties (supplying ink in a solid state B41J2/17593)}
- B41J 2/17503: {Ink cartridges}
- B41J 2/17513: {Inner structure}
- C09D 11/324: containing carbon black
- B41J: TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- 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

An inkjet recording ink including a pigment dispersion liquid containing at least a first carbon black and a dispersant, a second carbon black, a penetrant, a wetting agent and water, wherein the first carbon black has an average particle diameter D50 of 70 nm to 180 nm as measured by a dynamic light scattering method and has a particle diameter standard deviation equal to or smaller than ½ of the average particle diameter, wherein the dispersant is a condensate of naphthalene sulfonic acid and formalin, wherein the second carbon black is carbon black coated with a resin, and wherein the penetrant is a 2-ethyl-1,3-hexandiol.

## Claims

### Claim 1

An inkjet recording ink comprising:
a pigment dispersion liquid, comprising a first carbon black and a dispersant,
a second carbon black,
a penetrant,
a wetting agent,
a polyoxyalkylene derivative of the formula:
C18H27(C2H4O)nH,
wherein n is from 8 to 9, and
water,
wherein
the first carbon black has an average particle diameter D50 of from 70 nm to 180 nm as measured by a dynamic light scattering method and has a particle diameter standard deviation equal to or smaller than 1/2 of the average particle diameter,
the dispersant is a condensate of naphthalene sulfonic acid and formalin,
the second carbon black is carbon black coated with a resin, and
the penetrant is 2-ethyl-1,3-hexandiol.

### Claim 2 (depends on 1)

The inkjet recording ink of claim 1, further comprising an aqueous polyurethane resin.

### Claim 3 (depends on 2)

The inkjet recording ink of claim 2, wherein the aqueous polyurethane resin is an anionic self-emulsifying ether polyurethane.

### Claim 4 (depends on 2)

The inkjet recording ink of claim 2, wherein the aqueous polyurethane resin has an acid value of from 40 mgKOH/g to 120 mgKOH/g.

### Claim 5 (depends on 1)

The inkjet recording ink of claim 1, wherein an amount of 2-ethyl-1,3-hexandiol in the ink is from 0.1% by mass to 10% by mass.

### Claim 6 (depends on 5)

The inkjet recording ink of claim 5, wherein the amount of 2-ethyl-1,3-hexandiol in the ink is from 1.5% by mass to 5.0% by mass.

### Claim 7 (depends on 1)

The inkjet recording ink of claim 1, wherein a ratio by mass of the dispersant to the first carbon black is from 0.1 to 2.

### Claim 8 (depends on 1)

The inkjet recording ink of claim 1, wherein an amount of the wetting agent in the ink is from 5% by mass to 40% by mass.

### Claim 9

An ink cartridge comprising:
an inkjet recording ink, and
a container,
wherein the inkjet recording ink is housed in the container,
wherein the inkjet recording ink comprises a pigment dispersion liquid comprising a first carbon black and a dispersant, a second carbon black, a penetrant, a wetting agent, and water,
the first carbon black has an average particle diameter D50 of from 70 nm to 180 nm as measured by a dynamic light scattering method and has a particle diameter standard deviation equal to or smaller than 1/2 of the average particle diameter,
the dispersant is a condensate of naphthalene sulfonic acid and formalin,
the second carbon black is carbon black coated with a resin,
the penetrant is 2-ethyl-1,3-hexandiol, and
the inkjet recording ink comprises a polyoxyalkylene derivative of the formula:
C18H27(C2H4O)nH,
wherein n is from 8 to9.

### Claim 10 (depends on 9)

The ink cartridge of claim 9, wherein the inkjet recording ink further comprises an aqueous polyurethane resin.

### Claim 11 (depends on 10)

The ink cartridge of claim 10, wherein the aqueous polyurethane resin is an anionic self-emulsifying ether polyurethane.

### Claim 12 (depends on 10)

The ink cartridge of claim 10, wherein the aqueous polyurethane resin has an acid value of 40 mgKOH/g to 120 mgKOH/g.

### Claim 13 (depends on 9)

The ink cartridge of claim 9, wherein an amount of 2-ethyl-1,3-hexandiol in the ink is from 0.1% by mass to 10% by mass.

### Claim 14 (depends on 13)

The ink cartridge of claim 13, wherein the amount of 2-ethyl-1,3-hexandiol in the ink is from 1.5% by mass to 5.0% by mass.

### Claim 15 (depends on 9)

The ink cartridge of claim 9, wherein a ratio by mass of the dispersant to the first carbon black in the ink is from 0.1 to 2.

### Claim 16 (depends on 9)

The ink cartridge of claim 9, wherein an amount of the wetting agent in the ink is from 5% by mass to 40% by mass.