Patent ID: 7566518
Filing Date: 2009-07-28
Classification: G03G

Abstract:
1. A toner for electrostatic image development, obtainable by a process comprising the following steps: (I) melt-kneading a raw material mixture in which no external additive has been added, said mixture comprising a resin binder, a releasing agent, and a colorant, cooling the melt-kneaded mixture, and pulverizing the cooled mixture; (II) mixing a pulverized product obtained in the step (I) with an external additive comprising a negatively chargeable inorganic oxide subjected to hydrophobic treatment and a positively chargeable inorganic oxide subjected to hydrophobic treatment to form a mixture, and further pulverizing said mixture, and classifying the further pulverized product; and (III) mixing the product obtained in step (II) with an inorganic oxide having an average particle size larger than the external additive of step (II).