Ink comprising at least one water soluble-formazan dye, free from cellulose-reactive groups

Abstract

An ink comprising at least one water-soluble dye, free from cellulose-reactive groups, of the formula: ##STR1## wherein, R.sup.1 is --(C.sub.a H.sub.2a O).sub.m (C.sub.b H.sub.2b O).sub.n H, R.sup.2 is H or --(C.sub.a H.sub.2a O).sub.m (C.sub.b H.sub.2b O).sub.n H, or R.sup.1 and R.sup.2 together with the nitrogen atom form a morpholine ring; a and b are different and from 2 to 8 m is from 1 to 10; n is from 0 to 9; M is H, ammonium or sodium, potassium or lithium; X is (i) NR.sup.1 R.sup.2, (ii) NR.sup.3 R.sup.4, in which R.sup.3 and R.sup.4 are each independently selected from H, alkyl and aryl, or (iii) a mono- or dis-azo chromophore consisting of benzene, naphthalene or mono- or bi-cyclic heteroaryl diazo and coupling components linked to the triazine nucleus through an amino linking group, NR.sup.9, in which R.sup.9 is H, C.sub.1-4 -alkyl or phenyl; R.sup.5 and R.sup.6 are selected from SO.sub.3 M and H provided at least one is SO.sub.3 M; R.sup.7 is H, halogen, C.sub.1-4 alkyl, C.sub.1-4 alkoxy, SO.sub.3 M or COOM; and R.sup.8 is H or SO.sub.3 M. The ink is particularly suited for ink jet printing having improved solution stability, excellent recording properties, ejection stability, ejection responsiveness and continuous recording workability.

Dependencies are inferred from the claim text.