Patent ID: 6159649
Filing Date: 2000-12-12
Classification: C09B,C09D,G03G,H01G

Abstract:
A method of imparting color to an electrophotographic toner, an electrophotographic developer, a resin-containing powder or powdered coating composition, an electret material or an inkjet ink, comprising:preparing a composition of particles of an azo pigment of the formula (1) ##STR24## and 20 to 50% by weight of an auxiliary wherein said azo pigment is synthesized in the presence of 20 to 50% by weight of the auxiliary selected from the group consisting of a rosin, a salt of a rosin, an abietic acid, and a salt of an abietic acid, wherein said weight is based on the overall weight of the azo pigment including said auxiliary, and wherein the particles have a specific surface area of more than 70 m.sup.2 /g, a length-to-width ratio of on average less than 2.8:1 and a mean particle size d.sub.50 of less than 130 nm; andadding said particles and optionally a charge control agent to a binder.