Inkjet ink, method of manufacturing inkjet ink, ink cartridge, and inkjet recording device

Patent metadata

Field	Value
Publication number	US-9597891-B2
Application number	US-201514674361-A
Country	US
Kind code	B2
Filing date	Mar 31, 2015
Priority date	Apr 24, 2014
Publication date	Mar 21, 2017
Grant date	Mar 21, 2017

Abstract

An inkjet ink contains water, a hydrosoluble organic solvent, a pigment, polyvinyl pyrolidone, and a copolymer, wherein the copolymer contains a structure unit represented by Chemical formula 1,

where R 1 represents a hydrogen atom or a methyl group, R 2 is an alkyl group having one to four carbon atoms, M 1 + , M 2 + , M 3 + , and M 4 + each, independently represent protons, alkali metal ions, or organic ammonium ions, and
a structure unit represented by Chemical formula 2,

where R 3 represents a hydrogen atom or a methyl group,
a structure unit represented by Chemical formula 3,

where R 4 represents a hydrogen atom or a methyl group, or
a structure unit represented by Chemical formula 4,

where R 5 represents a hydrogen atom or a methyl group.

First claim

What is claimed is:

1. An inkjet ink, comprising:
water;
a hydrosoluble organic solvent;
a pigment;
polyvinyl pyrrolidone; and
a copolymer,
wherein:
the copolymer comprises a structure unit represented by formula (1) and at least one selected from the group consisting of a structural unit of formula (2), a structural unit of formula (3) and a structural unit of formula (4);
the structure unit represented by formula (1) is:

where
R 1 represents a hydrogen atom or a methyl group,
R 2 is an alkyl group having one to four carbon atoms,
M 1 + , M 2 + , M 3 + and M 4 + each, independently represent protons, alkali metal ions, or organic ammonium ions;

the structure unit represented by formula (2) is:

where R 3 represents a hydrogen atom or a methyl group;

the structure unit represented by formula (3) is:

where R 4 represents a hydrogen atom or a methyl group; and

the structure unit represented by formula (4) is:

where R 5 represents a hydrogen atom or a methyl group.

2. The inkjet ink according to claim 1 , wherein the copolymer comprises the structure unit represented by formula (1) in an amount of from 10% by weight to 60% by weight.

3. The inkjet ink according to claim 1 , wherein the copolymer comprises the structure unit represented by formula (4) and R 5 is a hydrogen bond.

4. The inkjet ink according to claim 1 , wherein the copolymer is synthesized by copolymerizing at least monomers of a compound represented by formula (5) and at least one selected from the group consisting of a compound represented by formula (6), a compound represented by formula (7) and a compound represented by formula (8);
wherein:
the compound represented by formula (5) is:

where
R 1 represents a hydrogen atom or a methyl group and
R 2 is an alkyl group having one to four carbon atoms;

the compound represented by formula (6) is:

where R 3 represents a hydrogen atom or a methyl group;

the compound represented by formula (7) is:

where R 4 represents a hydrogen atom or a methyl group; and

the compound represented by formula (8) is:

where R 5 represents a hydrogen atom or a methyl group.

5. The inkjet ink according to claim 1 , wherein 10% by weight aqueous solution of the copolymer has a viscosity of from 1.5 mPa·s to 30.0 mPa·s at 25° C.

6. The inkjet ink according to claim 1 , wherein M 1 + , M 2 + , M 3 + , and M 4 + are organic ammonium ions.

7. The inkjet ink according to claim 1 , further comprising resin particulates having a volume median diameter D 50 of from 70 nm to 250 nm.

8. A method of manufacturing an inkjet ink, the method comprising:
adjusting a pigment dispersion element in which a pigment is dispersed in water; and
manufacturing the inkjet ink of claim 1 using the pigment dispersion element

9. An ink cartridge, comprising:
a container; and
the inkjet ink of claim 1 that is accommodated in the container.

10. An inkjet recording device, comprising:
an ejection device to eject the inkjet ink of claim 1 .

Assignees

• Nonogaki Masayasu
• Naruse Mitsuru
• Matsuyama Akihiko
• Katoh Keita
• Nagai Kazukiyo
• Koizuka Yuusuke
• Ricoh Co Ltd

Inventors

• Nonogaki Masayasu
• Naruse Mitsuru
• Matsuyama Akihiko
• Katoh Keita
• Nagai Kazukiyo
• Koizuka Yuusuke

Classifications

• C09D143/02 Primary

  Homopolymers or copolymers of monomers containing phosphorus · CPC title

• C09D139/06

  Homopolymers or copolymers of N-vinyl-pyrrolidones · CPC title

• B41J2/2107 Primary

  characterised by the ink properties (supplying ink in a solid state B41J2/17593) · CPC title