| 摘要 |
PROBLEM TO BE SOLVED: To obtain an ink which can give a high-density nonbleeding water- resistant high-quality image to plain paper by mixing an amphoteric polymer with a specified compound. SOLUTION: The amphoteric polymer used is obtained by copolymerizing an anionic monomer with a cationic monomer, is exemplified by an allylamine/ maleic acid copolymer and has a weight-average molecular weight of 1,000-1,000,000 and an isoelectric point of 3-10. Its amount of addition is 0.1-30wt.% based on the ink. The specified compound is represented by formula I [wherein R1 is a 1-48C alkyl or H; R2 is (CH2 )a -X1 or H; R3 is (CH2 )b -X2 or the like; a and b are each 1-4; and X1 and X2 are each carboxyl, sulfone, H or the like, is exemplified by a compound represented by formula II and is used in an amount of 0.01-20wt.% based on the ink. The colorant used is a common dye or pigment. The liquid medium used is water or a water-soluble organic solvent. |
