| 摘要 |
PROBLEM TO BE SOLVED: To obtain the subject ink capable of exceeding in color tone as a magenta ink and improving light resistance and water resistance, containing both a quinacridone derivative and a free acid type xanthene-based compound as a colorant. SOLUTION: In this ink comprising (A) a colorant dispersible or soluble in water, (B) a water-soluble organic solvent and (C) water, the colorant of the component A is composed of both a quinacridone derivative of formula I (R1 and R2 are each an alkyl, a halogen or H) and a free acid type xanthene- based compound of formula II (X is H, sulfonic acid, sulfonamide, carboxylic acid, etc.,; Y is sulfonic acid) as a colorant. The particle diameters of the derivative of formula I in the ink are regulated to 0.01-0.1μm, and Na, Li, a quaternary ammonium of formula III (X is N or P; R3 to R6 are each H, a 1-4C alkyl, etc.) is used as the counter ion to the compound of formula II so as to increase reliability and the addition of a surfactant, etc., can improve delivery of ink after printing suspension for a long period of time. |
