Patent ID: 7927411

Claim:
A process for printing an image on a substrate comprising applying to the substrate, by means of an ink jet printer, an ink comprising a medium and compound of Formula (1) or a salt thereof: wherein: X is a naphthyl group substituted with at least one sulfonic acid group; Q 1 and Q 2 are each independently an optionally substituted arylene or polycyclic heteroarylene group each comprising a phenylene ring which is para connected to the —N═N— and the —NR— groups shown in Formula (1); each R independently is H, optionally substituted alkyl or optionally substituted aryl; Z is of Formula (5): wherein the asterisk (*) represents the point of attachment to the —N=N— group in the compound of Formula (1) or a salt thereof; each R a independently is a C 2-4 linear alkylene group; and each R b independently is H or methyl.