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