Abstract: An ink for inkjet recording includes water; a hydrosoluble solvent; a pigment; and a copolymer including a phosphonic acid group. The copolymer including a phosphonic acid group includes structural units having the following formulae (1) and (2): wherein R1 represents a hydrogen atom or a methyl group; and M represents a hydrogen atom, an alkali metal or an organic ammonium; and wherein R2 represents a hydrogen atom or a methyl group; R3 represents an alkyl group having 1 to 4 carbon atoms; and each of n and m represents 0 or an integer of from 1 to 30, provided n+m is from 2 to 30.

Abstract: Inkjet ink contains a pigment, a hydrosoluble solvent, and water, wherein the pigment is represented by the following chemical formula 1 and has a CuK? X-ray diffraction spectrum having a wavelength of 1.541 ? such that no main peak is observed at a Bragg (2?±0.2°) angle in a range of 2? of from 28.0° to 29.0°, wherein R represents a hydrogen atom, a methyl group, or a chlorine atom.

Abstract: An ink composition contains a pigment represented by the following chemical formula 1; a hydrosoluble solvent; and water, wherein the pigment satisfies the following relation 1:0.040<Y/X<0.200 (Relation 1), where, in a CuK? X-ray diffraction spectrum having a wavelength of 1.541 ?, X represents a peak intensity at a Bragg (2?±0.2°) angle in a range of 2? of from 26.5° to 27.5° and Y represents a peak intensity at a Bragg (2?±0.2°) angle in a range of 2? of from 11.0° to 11.

Abstract: An ink for inkjet recording contains water, an organic solvent, a pigment, and a compound represented by the following Chemical formula 1: In Chemical formula 1, M+'s each, independently represent protons, cations of alkali metals, ammonium ions, or organic ammonium ions.

Abstract: An ink composition contains a pigment, a polymer having a structure unit having a diphosphonic acid group, a hydrosoluble solvent, and water, and satisfies the following A and B. A: The pigment is represented by the following chemical formula 1a or chemical formula 1b. As for Chemical formula 1a, the pigment satisfies the relation 1: Y/X?0.800, where X and Y represent peak intensities at a Bragg (2?±0.2°) angle in a CuK? X-ray diffraction spectrum, when the pigment is represented by Chemical formula 1b, the pigment satisfies the relation 2: Y?/X??0.200, where X? and Y? represent peak intensities at a Bragg (2?±0.2°) angle in a CuK? X-ray diffraction spectrum, B. the structure unit having a diphosphonic acid group is represented by Chemical formula 2.

Abstract: Inkjet ink contains a pigment, a hydrosoluble solvent, and water, wherein the pigment is represented by the following chemical formula 1 and has a CuK? X-ray diffraction spectrum having a wavelength of 1.541 ? such that no main peak is observed at a Bragg (2?±0.2°) angle in a range of 2? of from 28.0° to 29.0°, wherein R represents a hydrogen atom, a methyl group, or a chlorine atom.

Abstract: An ink for inkjet recording includes water; a hydrosoluble organic solvent; a pigment; and a polymer including a first structural unit represented by the following formula (1): wherein R1 represents a hydrogen atom or a methyl group; and M+ represents at least one member selected from the group consisting of alkali metal ions, organic amine ions and hydrogen ions; and a second structural unit represented by the following formula (2) or (3): wherein each of R2 and R3 represents a methyl group or a hydrogen atom; n represents an integer of 18; x represents 0 or an integer of 2.

Abstract: An ink for inkjet recording, which is used for recording on a paper having a concentration of an eluted Ca ion of from 1.0×10?4 to 5.0×10?4 g/g when dipped in pure water. The ink includes at least a pigment, a pigment dispersant, a water-soluble organic solvent and water. The pigment dispersant is a copolymer synthesized using at least (1) unsaturated ethylene monomer having a phosphoric acid group or a phosphonic acid group and (2) unsaturated ethylene monomer having an alkyl group having 12 to 22 carbon atoms.

Abstract: An inkjet recording ink, including: water; a water-soluble solvent; a pigment; and a phosphoric acid group-containing copolymer, wherein the phosphoric acid group-containing copolymer contains at least a structural unit represented by General Formula (1) and a structural unit represented by General Formula (2): where in General Formula (1), R1 represents a hydrogen atom or a methyl group, M+ represents a proton, an alkali metal ion, or an organic ammonium ion, k and l are each an integer of 0 to 6, with the proviso that the case where k and l are 0 at the same time is excluded, where in General Formula (2), R2 represents a hydrogen atom or a methyl group, R3 represents an alkyl group having 1 to 4 carbon atoms, n and m are each an integer of 0 to 30, with the proviso that n+m is 2 to 30.

Abstract: An ink for inkjet recording includes water; a hydrosoluble organic solvent; a pigment; and a polymer including a first structural unit represented by the following formula (1): wherein R1 represents a hydrogen atom or a methyl group; and M+ represents at least one member selected from the group consisting of alkali metal ions, organic amine ions and hydrogen ions; and a second structural unit represented by the following formula (2) or (3): wherein each of R2 and R3 represents a methyl group or a hydrogen atom; n represents an integer of 18; x represents 0 or an integer of 2.

Abstract: An ink for inkjet recording including a pigment, a penetrating agent and water, wherein the pigment includes: an ozone-oxidized carbon black, including carbon black oxidized by ozone and having a volatile matter content of the carbon black of 10% by mass to 20% by mass and a BET specific surface area of 90 m2/g to 150 m2/g; and a resin-coated carbon black, including: carbon black; and a resin present on a surface of the carbon black.

Abstract: An inkjet ink that contains at least water; a water-soluble organic solvent; a pigment; and a copolymer or a salt thereof. The copolymer or the salt thereof has at least a structural unit represented by Formula 1, a structural unit represented by Formula 2, and a structural unit represented by Formula 3 or 4.

Abstract: An ink composition contains a pigment; a copolymer comprising a phosphoric acid group or phosphonic acid group; a hydrosoluble solvent; and water, wherein the pigment is represented by the following chemical formula 1 and satisfies the following relation 1: Y/X?0.20??Relation 1 where X represents a peak intensity at a Bragg (2?±0.2°) angle in a range of 2? of from 26.5° to 27.5° and Y represents a peak intensity at a Bragg (2?±0.2°) angle in a range of 2? of from 11.0° to 11.5° to a CuK? X-ray having a wavelength of 1.541 ?.

Abstract: An ink composition contains a pigment; a copolymer containing a phosphoric acid group or phosphonic acid group; a hydrosoluble solvent; and water, wherein the pigment is represented by the following chemical formula 1 and satisfies the following relation 1: Y<X<0.8, where X represents a peak intensity at a Bragg (2?±0.2°) angle in a range of 2? of from 5.5° to 6.0° and Y represents a peak intensity at a Bragg (2?±0.2°) angle in a range of 2? of from 26.5° to 27.5° to a CuK? X-ray having a wavelength of 1.541 ?. where R each, independently represents monovalent groups selected from hydrogen atoms, methyl groups, or chlorine atoms.

Abstract: An ink for inkjet recording includes water; a hydrosoluble solvent, a pigment, and a copolymer including a salt of a diphosphonic acid group. The copolymer including a salt of a diphosphonic acid group includes structural units having the following formulae (1) and (2): X represents an alkylene group having 1 to 3 carbon atoms, each of R1 and R2 represents a hydrogen atom or a methyl group, M+ represents an alkali metal ion, an organic ammonium ion or a proton and Z1 represents a hydrocarbon group having 6 to 22 carbon atoms. The alkali metal ion or the organic ammonium ion and the proton may be mixed, and half or more of the M+ are alkali metal ions or the organic ammonium ions.

Abstract: An ink for inkjet recording, which is used for recording on a paper having a concentration of an eluted Ca ion of from 1.0×10?4 to 5.0×10?4 g/g when dipped in pure water. The ink includes at least a pigment, a pigment dispersant, a water-soluble organic solvent and water. The pigment dispersant is a copolymer synthesized using at least (1) unsaturated ethylene monomer having a phosphoric acid group or a phosphonic acid group and (2) unsaturated ethylene monomer having an alkyl group having 12 to 22 carbon atoms.

Abstract: An inkjet recording ink, including: water; a water-soluble solvent; a pigment; and a phosphate group-containing copolymer, wherein the phosphate group-containing copolymer includes a structural unit represented by the following general formula (1) and a structural unit represented by the following general formula (2): wherein, in the general formula (1), R1 represents either of a hydrogen atom and a methyl group; and M+ represents any of an alkali metal ion, an organic amine ion and a hydrogen ion, one-half or more of the M+ in the copolymer is an alkali metal ion or an organic amine, and the remainder is a hydrogen ion; wherein, in the general formula (2), R2 represents either of a hydrogen atom and a methyl group.

Abstract: An inkjet recording ink, including: water; a water-soluble solvent; a pigment; and a phosphate group-containing copolymer, wherein the phosphate group-containing copolymer includes a structural unit represented by the following general formula (1) and a structural unit represented by the following structural formula (1): wherein, in the general formula (1), R1 represents either of a hydrogen atom and a methyl group; and M+ represents any of an alkali metal ion, an organic ammonium ion, an organic amine ion and a hydrogen ion, one-half or more of the M+ in the copolymer is an alkali metal ion, an organic ammonium ion or an organic amine, and the remainder is a hydrogen ion:

Abstract: An inkjet ink that contains at least water; a water-soluble organic solvent; a pigment; and a copolymer or a salt thereof. The copolymer or the salt thereof has at least a structural unit represented by Formula 1, a structural unit represented by Formula 2, and a structural unit represented by Formula 3 or 4. In Formula 1, R1 represents a methyl group or a hydrogen atom, M+s each represent a hydrogen ion, an alkali metal ion, or an organic ammonium ion, and m and n each, independently represent 0 or an integer of from 1 to 6 excluding a case of both m and n being 0 at the same time. In Formula 2, R2 represents a methyl group or a hydrogen atom. In Formula 3, R3 represents a methyl group or a hydrogen atom.

Abstract: An inkjet recording ink including: water; a first pigment dispersion; a second pigment dispersion; and a penetrating agent, wherein the first pigment dispersion includes oxidized carbon black CB-1 dispersed therein with a pH of the first pigment dispersion adjusted to 6 to 8 with an alkali metal hydroxide, where the oxidized carbon black CB-1 is oxidized with ozone and has a volatile content of 10% to 20% and a BET specific surface area of 90 m2/g to 150 m2/g, and the second pigment dispersion includes carbon black CB-2 dispersed therein with a naphthalene sulfonic acid-formalin condensate, where the carbon black CB-2 has an average particle diameter (D50) of 50 nm to 180 nm as measured by a dynamic light scattering method and a standard deviation of particle diameters of the carbon black CB-2 is equal to or lower than ½ of the average particle diameter.