DEVELOPMENT METHOD AND DEVELOPMENT DEVICE

摘要

PROBLEM TO BE SOLVED: To obtain excellent image density without generating a fading phenomenon even when printed over a long term under various environment.SOLUTION: A development method comprises steps of: carrying a developer to a development region faced to a latent image carrier while controlling the carrying amount of the developer on a developer carrier using a layer thickness controlling member; and visibly imaging an electrostatic latent image formed in the latent image carrier. The developer includes toner particles including a binder resin and a magnetic iron oxide, and a fluidity imparting agent. The number average particle size Dn of the magnetic iron oxide is 0.05-0.15 μm and Dn (μm) and the specific surface area S (m/g) of the magnetic iron oxide satisfy the relationship of Dn×S≤1.20. The developer carrier has a base and a resin layer including conductive fine particles formed on the base. The resin layers of the developer and developer carrier have a negative frictional electrification polarity to ferrite particles coated by a polymethyl methacrylate resin, and the developer has a negative frictional electrification polarity to the developer carrier.SELECTED DRAWING: None