US Patent 7566520 Liquid developer

A liquid developer of the type that is positively-charged is provided. The liquid developer includes an insulation liquid, and toner particles dispersed in the insulation liquid, wherein each of the toner particles includes a toner matrix particle mainly made of a polyester resin and a positively-charged polymeric dispersant adhering to the surface of the toner matrix particle. The polymeric dispersant is preferably of the type that an amino group is contained in its molecule, or of the type that an ester structure is contained in its molecule. Further, the polyester resin is preferably of the type that a —SO3− group is contained in its molecule. The liquid developer has excellent positively-chargeable charging characteristics and fixing characteristics.