A water-based ink of the present invention comprises water, a plurality of different water-soluble organic solvents, and a water-insoluble coloring material, wherein the above water-soluble organic solvents consist of a good solvent to the above water-insoluble coloring material and a poor solvent to the above water-insoluble coloring material, and the total amount (% by mass) of the good solvents in the ink is represented by A and the total amount (% by mass) of the poor solvent in the ink is represented by B, the ratio of A to B ranges from 10:5 to 10:30 both inclusive, and when the respective Ka values of the above water-soluble organic solvents are determined by the Bristow method and compared with each other, a water-soluble organic solvent having the greatest Ka value is the poor solvent. The pigment ink has a sufficiently large area factor even with a small amount of ink and provides an image of high OD.
本发明的一种
水性油墨包括
水、多种不同的
水溶性有机溶剂和不溶于
水的着色材料,其中上述
水溶性有机溶剂包括对上述不溶于
水的着色材料的良好溶剂和对上述不溶于
水的着色材料的不良溶剂、油墨中良好溶剂的总量(质量百分比)用 A 表示,油墨中不良溶剂的总量(质量百分比)用 B 表示,A 与 B 的比例范围为 10:当用布里斯托法测定上述
水溶性有机溶剂各自的 Ka 值并相互比较时,Ka 值最大的
水溶性有机溶剂为劣溶剂。这种
颜料油墨即使用少量油墨也有足够大的面积系数,并能提供高外显度的图像。