Patent ID: 8328341

Claim:
An ink jet recording ink comprising (a) a self-dispersion pigment, to the surface of which an anionic functional group represented by the following general formula (I) has been bonded directly or through another atomic group, (b) water, (c) a water-soluble substance having a coefficient of hydrophilicity-hydrophobicity of 0.37 or more as defined by the following equation (A), (d) a water-soluble substance having a coefficient of hydrophilicity-hydrophobicity of 0.25 or less as defined by the equation (A), and (e) an ethylene oxide adduct of acetylene glycol having a HLB value of 10 or more, the ink-jet recording ink having a surface tension of 34 mN/m or less, wherein the water-soluble substance having a coefficient of hydrophilicity-hydrophobicity of 0.37 or more is a water-soluble compound (1) having a glycol structure of a hydrocarbon having 4 to 7 carbon atoms, wherein the water-soluble substance having a coefficent of hydrophilicity-hydrophobicity of 0.25 or less is a water-soluble compound (2), such that the proportion (1)/(2) of the content of the water-soluble compound (1) to the content of the water-soluble compound (2) in the ink is 1/5 or more and 5/1 or less, and the ethylene oxide adduct of acetylene glycol is contained in the ink in an amount of 0.2% by mass or more and 5% by mass or less: wherein M 1 and M 2 are, independently of each other, a hydrogen atom, alkali metal, ammonium, or organic ammonium; Coefficient of hydrophilicity-hydrophobicity=[(Water activity value of a 20% aqueous solution)−(Molar fraction of water in the 20% aqueous solution)]/[1−(Molar fraction of water in the 20% aqueous solution)] Equation (A).