Patent ID: 6174354
Filing Date: 2001-01-16
Classification: C09D

Abstract:
An ink comprising:an anionic dye,a solvent for dissolving the anionic dye,an ampholytic polymer having an isoelectric point in a pH range of 3 to 10, the polymer being a copolymer of a monomer having an anionic group and a monomer having a cationic group, anda compound represented by the following general formula (A): ##STR4##wherein R.sub.1 represents a hydrogen atom or an alkyl group having 1 to 48 carbon atoms; R.sub.2 represents a hydrogen atom or (CH.sub.2).sub.a --X.sub.1 where a is an integer of 1 to 4; R.sub.3 represents a hydrogen atom, (CH.sub.2).sub.b --X.sub.2, or R.sub.4 --Y where b is an integer of 1 to 4; R.sub.4 represents a hydrogen atom or an alkyl group having 1 to 48 carbon atoms; Z represents (NR.sub.5 C.sub.l H.sub.2l).sub.c (NHC.sub.n H.sub.2n).sub.d, where each of l and n is an integer of 2 to 4, c+d is an integer of 0 to 50; Y represents (NR.sub.6 C.sub.m H.sub.2m).sub.e (NHC.sub.p H.sub.2p).sub.f, where each of m and p is an integer of 2 to 4, e+f is an integer of 0 to 50; R.sub.5 represents (CH.sub.2).sub.g --X.sub.3, where g is an integer of 1 to 4; R.sub.6 represents (CH.sub.2).sub.h --X.sub.4, where h is an integer of 1 to 4; each of X.sub.1, X.sub.2, X.sub.3, and X.sub.4 is selected from a group consisting of a carboxyl group, salts of the carboxyl group, a sulfonic group, salts of the sulfonic group, and a hydrogen atom; and when each of R.sub.2 and R.sub.3 is a hydrogen atom, c and e are not both zero, and X.sub.1, X.sub.2, X.sub.3, and X.sub.4 are not all hydrogen atoms,wherein the ink has a higher pH than the isoelectric point of the polymer, and wherein the pH of the ink is set such that application of the ink onto a plain paper causes (1) the pH of the ink to be equal to the isoelectric point of the ampholytic polymer and (2) the anionic dye to react with the ampholytic polymer.