| 摘要 |
PROBLEM TO BE SOLVED: To provide an ink that shows excellent resistances to light and water, even when this ink is printed to a variety of plain papers. SOLUTION: In an ink including at least water, a water-soluble organic solvent and dyes, a compound having the molecular structure of the formula (Q1 is a phenyl group, pyridyl group or naphthyl group substituted with a group selected from NH2 and SO3M; Q2 is a p-phenylene or 1,4-naphthylene group substituted with CH3, OCH3, NHCOCH3, and SO3M; Q3 is a diaminopyridyl group unsubstituted of substituted with SO3M, or diaminophenyl group substituted with COOM or SO3M; M is an alkali metal, ammonium or an organic ammonium; n is 0 or 1) and bears individually 2 or more sulfonic acid groups and amino groups in one molecule where the number of the sulfonic acid groups is smaller than that of the amino groups. This dye is included in the ink in an amount of 0.20-20 wt.% based on the whole amount of the ink. |
