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: A copolymer includes a structure unit represented by Chemical Formula I; and a structure unit represented by Chemical Formula II, where R1 and R2 each, independently represent hydrogen atoms or methyl groups, X represents a hydrogen atom or a cation, and L represents an alkylene group having 2 to 18 carbon atoms.

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 organic solvent; a pigment; and a phosphate group-containing copolymer, wherein the phosphate group-containing copolymer contains a structural unit represented by the following General Formula (1) and a structural unit represented by the following General Formula (2): where R1 denotes a hydrogen atom or a methyl group; M+ denotes an alkali metal ion, an organic amine ion, or a hydrogen ion; half or more of M+ in the copolymer is the alkali metal ion or the organic amine ion, the remainder of M+ is the hydrogen ion; n and m each denote an integer of 0 to 6, provided that both of n and m are not 0; and a block of (C2H4O) and a block of (C3H6O) may be exchanged with each other, where R2 denotes a hydrogen atom or a methyl group.

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 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 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 R1 represents a hydrogen atom or a methyl group, R2 is an alkyl group having one to four carbon atoms, M1+, M2+, M3+, and M4+ each, independently represent protons, alkali metal ions, or organic ammonium ions, and a structure unit represented by Chemical formula 2, where R3 represents a hydrogen atom or a methyl group, a structure unit represented by Chemical formula 3, where R4 represents a hydrogen atom or a methyl group, or a structure unit represented by Chemical formula 4, where R5 represents a hydrogen atom or a methyl group.

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: The present invention provides an ink composition that contains a pigment, a dispersant, a hydrosoluble solvent; and water, wherein the pigment is represented by the following chemical formula 1: where R represents hydrogen, an alkyl group having one to three carbon atoms, or chlorine, wherein the ink composition satisfies the following relations 1 and 2: 0.050?X/Y?0.120??Relation 1 0.700?Z/Y?1.050??Relation 2 where X represents a minimum absorbance in a wavelength range of from 400 nm to 450 nm, Y represents an absorbance of a maximum peak in a wavelength range of from 500 nm to 550 nm, and Z represents an absorbance of a maximum peak in a wavelength range of from 550 nm to 600 nm.

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: A yellow ink composition includes a particulate pigment; a dispersant; a water-soluble solvent; and water, wherein the ink composition satisfies the following relationship: 0.02?Y/X?0.07??(1) wherein X represents a maximum absorbance of the ink composition at a wavelength of from 400 to 450 nm; and Y represents an absorbance thereof at a wavelength of 500 nm.

Abstract: The present invention provides an ink composition that contains a pigment, a dispersant, a hydrosoluble solvent; and water, wherein the pigment is represented by the following chemical formula 1: where R represents hydrogen, an alkyl group having one to three carbon atoms, or chlorine, wherein the ink composition satisfies the following relations 1 and 2: 0.050?X/Y?0.120??Relation 1 0.700?Z/Y?1.050??Relation 2 where X represents a minimum absorbance in a wavelength range of from 400 nm to 450 nm, Y represents an absorbance of a maximum peak in a wavelength range of from 500 nm to 550 nm, and Z represents an absorbance of a maximum peak in a wavelength range of from 550 nm to 600 nm.

Abstract: An inkjet recording ink set including a black ink and color inks, wherein the black ink and the color inks each contain at least a dye, a water-soluble solvent and water and each have a viscosity of 5 mPa-s to 20 mPa-s at 25° C., and wherein the respective color inks each satisfy a mass ratio relationship of S/W?1, and the black ink satisfies a mass ratio relationship of S/W<1, where S denotes an amount of the water-soluble solvent contained in the respective inks, and W denotes an amount of the water contained in the respective inks.

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.