Patent ID: 8133314

Claim:
An ink composition comprising at least a pigment, a water-soluble organic solvent, a humectant, and water in an amount from 10 to 60% by weight to of the total amount of the ink composition, wherein the water-soluble organic solvent is 1,2-alkanediol and/or glycol ether, and wherein the humectant is a mixture of the following compounds (A), (B), and (C): (A) at least one compound selected from glycerin, 1,2,6-hexanetriol, diethylene glycol, triethylene glycol, tetraethylene glycol, and dipropylene glycol, (B) either trimethylol propane or trimethylol ethane, or a mixture thereof, and (C) at least one compound selected from the group consisting of betaines, saccharides, and ureas and having a molecular weight in the range of from 100 to 200, at a content weight ratio of (A):(B):(C) of 1.0:0.1 to 1.0:1.0 to 3.5.