Patent ID: 7442244

Claim:
A water-base ink composition comprising at least: a colorant component selected from dyes and pigments; a monovalent or divalent branched alcohol with C5 to C10 chain length; an acetylene glycol surfactant; a penetrating organic solvent; a humectant; and water, said monovalent or divalent branched alcohol with C5 to C10 chain length, said acetylene glycol surfactant, said penetrating organic solvent, and said humectant being selected from combinations of monovalent or divalent branched alcohols with C5 to C10 chain length, acetylene glycol surfactants, penetrating organic solvents, and humectants such that the water, said monovalent or divalent branched alcohol with C5 to C10 chain length, said acetylene glycol surfactant, said penetrating organic solvent, and said humectant are miscible with one another, wherein the content of the monovalent or divalent branched alcohol with C5 to C10 chain length in the ink is 0.1 to 10% by weight based on the total weight of the ink, the content of the acetylene glycol surfactant in the ink is 0.01 to 10% by weight based on the total weight of the ink, the penetrating organic solvent is selected from the group consisting of monohydric alcohols, glycol monoether derivatives of polyhydric alcohols, and 1,2-alkyldiols, the content of the monohydric alcohol in the ink is 0.5 to 10% by weight based on the total weight of the ink, the content of the glycol monoether derivative of polyhydric alcohol in the ink is 0.5 to 15% by weight based on the total weight of the ink, and the content of the 1,2-alkyldiol in the ink is 0.25 to 5% by weight based on the total weight of the ink, and wherein the monovalent or divalent branched alcohol with C5 to C10 chain length is 2-ethyl-1,3-hexanediol, and the humectant comprises a water-soluble humectant having a melting point of 30° C. or above.