IMPROVED ELECTROPHOTOGRAPHIC DEVELOPER

PURPOSE:To ensure a developer having characteristics superior in resistance to toner filming, cleanability, abrasion resistance, etc., by incorporating an A-B type block copolymer having fluoroalkyl groups in the developer. CONSTITUTION:The toner of the developer contains an A-B type block copolymer composed of compatible segments A compatible with other resins and the segments B of the fluoroalkyl groups having surface migrability, that is, the functional segments B, in a amt. of 1-10wt%, thus permitting the fluoroalkyl groups of the functional segments B to be oriented on the surface of the toner, resistance to toner filming, cleanability, abrasion resistance, and high-humidity resistance of the surface of a photosensitive body to be remarkably improved, and the compatible segments A to become compatible with other binder resins in the inside of the toner and, accordingly, to enhance adhesiveness and durability.