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 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 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 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 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 ink composition having organic pigment particles, a hydrosoluble solvent; a dispersing agent, and water, wherein each of the organic pigment particles has a circularity of 2 nm or less, which is defined as a difference between radii of concentric circumscribing and inscribed circles of a contour of an image of each of the organic pigment particles taken by a transmission electron microscope when a gap between the concentric circumscribing circle and the inscribed circle is least, wherein the inscribed circle has a diameter of from 5 nm to less than 50 nm.

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 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 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 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 ink set including at least a black ink, a cyan ink, a magenta ink, and a yellow ink. Each of the inks includes at least a water-soluble dye, water and a water-soluble solvent including a specific alkoxypropionamide compound. The cyan, magenta and yellow inks has a S/W ratio of not less than 1.5 and not greater than 3.5, wherein S represents the content of the water-soluble solvent in each ink, and W represents the content of water in each ink, and the black ink has a S/W ratio of not less than 1.0 and less than 1.5, wherein S represents the content of the water-soluble solvent in the black ink, and W represents the content of water in the black ink.

Abstract: An inkjet recording ink including a water-soluble organic solvent, a colorant, at least one fluorine-based surfactant having a chemical structure represented by Structural Formula (I) below, and water, where Rf represents any one of CF3, CF2CF3, (CF2)3F, and (CF2)4F, and X plus Y is an integer of 4 or 5.

Abstract: An ink for inkjet recording, containing: dispersed particles A; dispersed particles B; a water-soluble solvent; a surfactant; and water, wherein the dispersed particles A are coloring particles obtained by dispersing an organic pigment in water with assistance of a surfactant, and the dispersed particles B are coloring particles obtained by dispersing a polymer-coated organic pigment in water.

Abstract: An ink for inkjet recording includes water; a water-soluble solvent; a pigment; and a copolymer including a salt of phosphonic acid group.

Abstract: An inkjet recording ink including: a colorant; surfactant A; surfactant B; a water-soluble organic solvent; and water, wherein the surfactant A is represented by General Formula (1), and the surfactant B is at least one selected from compounds represented by General Formulas (2a) and (2b): where Rf represents CF3, CF2CF3, (CF2)3F or (CF2)4F, X and Y each are an integer of 1 or greater, and X+Y=4 or 5; where R3 and R4 each represent a hydrogen atom or a C1-20 alkyl group, r is a real number of 0 to 7, and s is a real number of 1 to 10, where each of R3 and R4 represents a hydrogen atom or a C1-20 alkyl group, t is a real number of 0 to 7, and u is a real number of 1 to 10.

Abstract: An ink for inkjet recording includes water, a water-soluble solvent, a pigment and a copolymer including a salt of phosphonic acid group. The copolymer including a salt of phosphonic acid group includes structural units having the following formulae (1) and (2) or (3): wherein not less than half or all of M+ represent a cation of alkali metals or an organic ammonium ion, and the rest represents proton; wherein Ar1 represents a monovalent group of benzene or naphthalene; and wherein R1 represents an alkyl group having 5 to 20 carbon atoms.

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: The present invention provides an inkjet ink containing at least a colorant, water, a water insoluble resin, a fluorine surfactant, and a polyether-modified silicone oil, wherein the polyether-modified silicone oil has a hydrophobic value of 0.40 to 1.5, and the hydrophobic value is expressed by Equation 1; Hydrophobic value=A/B??Equation 1 where “A” represents an integration value of a peak area from 0 ppm to 0.3 ppm in a 1H-NMR spectrum of the polyether-modified silicone oil using tetramethylsilane as a reference substance; and “B” represents an integration value of a peak area from 3.5 ppm to 4.0 ppm in the 1H-NMR spectrum.

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.