Patent ID: 6905807

Claim:
A liquid ink comprising: a) a carrier liquid having a Kauri-Butanol number less than 30; characterized in that it further includes b) a grafted co-polymer comprising a copolymeric or polymeric steric stabilizer covalently bonded to a thermoplastic copolymeric or polymeric core that is insoluble in the carrier liquid, wherein the grafted co-polymer is derived from at least a polymerizable organic compound having at least one acid group or at least one basic group; c) a dispersant having, respectively, at least an amine group or at least one acid group to form an acid-base copolymer-dispersant system or a base-acid copolymer-dispersant system, wherein the mole ratio of the amine group to the acid group is between 0.3 and 1.5 in the base-acid copolymer-dispersant system and the mole ratio of the acid group to the base group in the acid-base copolymer dispersant system is between 0.3 and 1.5; and d) a positive charge director used with the acid-base copolymer-dispersant system or a negative charge director used with the base-acid copolymer-dispersant system.