Bleed resistance of dyes by counter-ion substitution.

摘要

A thermal ink jet ink comprises (a) ca. 0.5-40 wt.% of a low vapour pressure solvent; (b) ca. 0.1-8 wt.% of a sulphonate or carboxylate dye with an amine-contg. counter ion having the formula: +N-(CH3)mH3-m-(CH2)n-R (I) m = 1-3; n = 3-6 and R = a hydrophilic substituent or cycloaliphatic or aromatic gp. with a hydrophilic substituent, the amine-contg. counterion replacing any cation previously associated with the dye; and (c) water. A method of reducing bleed between colour inks in a thermal jet printer by use of the claimed inks is also claimed.