MAGNETIC TONER AND ELECTROPHOTOGRAPHIC METHOD

摘要

PURPOSE:To obtain a magnetic toner which produces no toner filming by using a specified org. photosensitive body and a magnetic toner comprising silica fine particles and polyvinylidene fluoride fine particles as an external additive. CONSTITUTION:This photosensitive body is such an org. photosensitive body that at least its surface layer contains a polycarbonate resin, org. photoconductive material and additive (silicone oil) expressed by formula I. Moreover, the magnetic toner consists of at least a binder resin, magnetic material and external additive. This external additive consists of hydrophobic silica fine particles the surface of which is treated with a treating agent expressed by formula I and fine particles (polyvinylidene fluoride fine particles) expressed by formula II. The external additive used for the magnetic toner is obtd. by subjecting hydrophobic silica fine particles obtd. by processing silicon tetrachloride with silicone oil to surface treatment with silicone oil. The surface treatment of silica fine particles is performed by a well-known method such as a mixing or spraying method.