Patent ID: 8388125

Claim:
An inkjet recording ink having a surface tension of 34 mN/m or less, the inkjet recording ink comprising: water; an anionic self-dispersion pigment having an anionic functional group; a cesium ion; and a water-soluble compound having a hydrophilicity/hydrophobicity coefficient of 0.26 or more, wherein the inkjet recording ink contains X mol/g in total of the anionic functional group and Y mol/g of the cesium ion, satisfying the relationship X<Y, and wherein the hydrophilicity/hydrophobicity coefficient is defined by equation (A): Hydrophilicity / hydrophobicity ⁢ ⁢ coefficient = ( 20 ⁢ % ⁢ ⁢ aqueous ⁢ ⁢ solution ⁢ ⁢ water ⁢ ⁢ activity ) - ( molar ⁢ ⁢ fraction ⁢ ⁢ water ⁢ ⁢ in ⁢ ⁢ 20 ⁢ % ⁢ ⁢ aqueous ⁢ ⁢ solution ) 1 - ( molar ⁢ ⁢ fraction ⁢ ⁢ of ⁢ ⁢ water ⁢ ⁢ in ⁢ ⁢ 20 ⁢ % ⁢ ⁢ aqueous ⁢ ⁢ solution ) . ( A )