Abstract: A magnetic brush developing device comprising a developing roller including a cylindrical stationary magnet and a sleeve rotatably mounted around the magnet, the developing roller being disposed adjacent the surface of a latent image bearing member, the cylindrical magnet having a developing magnetic pole facing the surface of the latent image forming member and transporting magnetic poles respectively disposed above and below the developing magnetic pole in adjacent relation thereto, the transporting magnetic poles being narrower in width than and having an opposite polarity to the developing magnetic pole.

Abstract: A magnetic brush developer for use in electrophotographic copiers or the like, the developer comprising a magnet support shaft fixedly mounted with respect to the copier; a hollow, cylindrical magnet fixedly mounted on the support shaft; a hollow cylinder rotatably, concentrically mounted about the cylindrical magnet, the cylinder having at least one side, the one side including an annular support member for the cylinder where the support member is rotatably mounted on the magnet support shaft and projects inside of the cylinder to thereby provide a compact arrangement for the developer.