Patent ID: 7056634

Claim:
A yellow toner comprising a yellow toner particle that contains at least a binder resin, a wax, and a yellow pigment containing a monoazo compound represented by a formula (1) as follows, wherein a value of a* is in the range of −5 to +14 when b* is +80 with respect to a transmission chromaticity of a thermally fixed image formed on a transparency sheet using the toner wherein X 1 to X 6 each independently denotes a substituents selected from the group consisting of a hydrogen atom, a C1–3 alkyl group, a C1–3 alkoxyl group, a nitro group, a halogen group, a sulfonic group, a sulfamoyl group, a sulfamoyl group substituted with an aromatic group, a carboxyl group, and a carboxylate; each may bond with another to form a benzene ring without a substituent or an imidazolone ring without a substituent; or each may bond with another to form a benzene ring with the above-mentioned substituent or an imidazolone ring with above-mentioned substituents; wherein the yellow pigment is prepared by conducting a coupling reaction in an aqueous solution containing 5 to 500 parts by mass of a water-soluble resin with respect to 100 parts by dry mass of the yellow pigment produced in a reaction; and wherein the water-soluble resin comprises a sulfonic group or a salt thereof.