Patent ID: 8016929

Claim:
A water-based ink for ink-jet recording comprising a coloring agent, water, a water-soluble organic solvent, and an acetylene glycol surfactant, wherein the coloring agent comprises a dye represented by the following general formula (1), the water-soluble organic solvent comprises dipropylene glycol propyl ether, the acetylene glycol surfactant comprises a surfactant represented by the following general formula (2), and wherein the dye represented by the general formula (1), dipropylene glycol propyl ether, and the surfactant represented by the general formula (2) are blended so as to satisfy the following conditions (A) to (C): (A) an amount of a dye represented by general formula (1) relative to a total amount of the ink is in a range of about 0.1 wt % to 1.0 wt % (B) an amount of dipropylene glycol propyl ether relative to a total amount of the ink is in a range of about 0.5 wt % to about 3 wt % (C) in a case of y≧25x19+2/9 −175 x+ 18 y+ 225 z− 104≦0 and −100 x+ 18 y+ 225 z− 66.5≧0 in a case of y≦25x/9+2/9 −275 x+ 54 y+ 225 z− 112≦0 and −200 x+ 54 y+ 225 z− 74.5≧0 x: an amount of a dye represented by general formula (1) relative to a total amount of the ink (wt %) y: an amount of dipropylene glycol propyl ether relative to a total amount of the ink (wt %) z: an amount of a surfactant represented by general formula (2) relative to a total amount of the ink (wt %) wherein in the general formula (1), R 1 represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group; R 2 represents a hydrogen atom, a halogen atom, or a cyano group; R 3 represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group; R 4 , R 5 , R 6 and R 7 , each independently, represent a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocyclic group, a substituted or unsubstituted sulfonyl group, or a substituted or unsubstituted acyl group, provided that R 4 , R 5 , R 6 and R 7 may be the same or different, that R 4 and R 5 are not simultaneously hydrogen atoms, and that R 6 and R 7 are not simultaneously hydrogen atoms; and A 1 and A 2 are both substituted or unsubstituted carbon atoms, or one of A 1 and A 2 is a substituted or unsubstituted carbon atom and the other is a nitrogen atom: wherein in the general formula (2), m and n may be the same or different and indicate numbers that satisfy m+n=1 to 15; and R 11 , R 12 , R 13 and R 14 may be the same or different and are straight chain or branched-chain alkyl groups having 1 to 5 carbon atoms.