Patent ID: 7635550

Claim:
A method of producing a liquid developer which comprises an insulation liquid and toner particles dispersed in the insulation liquid, the method comprising: preparing an insulation liquid containing an antioxidant being tocopherol; preparing a kneaded material containing a coloring agent and a resin material, the kneaded material being in a solid state; grinding the kneaded material to obtain a ground kneaded material in the form of resin particles; heating the insulation liquid at a predetermined temperature, and adding the ground kneaded material to the heated insulation liquid so that the ground kneaded material is transformed into a molten state ground kneaded material; dispersing the molten state ground kneaded material in the heated insulation liquid to obtain a molten state kneaded material dispersed liquid in which the molten state ground kneaded material is finely dispersed in the form of fine particles of the molten state ground kneaded material; and cooling the molten state kneaded material dispersed liquid to solidify the fine particles of the molten state kneaded material so that the fine particles of the molten state kneaded material are transformed into the toner particles; wherein the insulation liquid contains an unsaturated fatty acid and the amount of the unsaturated fatty acid contained in the insulation liquid is 75 wt % or more, and wherein when the predetermined heating temperature of the insulation liquid is defined as Th (° C.), a softening point of the resin material is defined as T f (° C.), and a boiling point of the insulation liquid is defined as Tb (° C.), relations of both T f +5≦Th≦T f +10 and T f +10≦Tb−10 are satisfied.