CARRIER FOR ELECTROPHOTOGRAPHIC DEVELOPING AGENT AND ITS PRODUCTION

PURPOSE:To obtain the carrier which has excellent picture quality for a long period by composing the carrier of a core part comprising a resin and an outer layer part comprising magnetic particles. CONSTITUTION:The core part of the carrier is composed of the resin, and the outer part thereof is composed of the magnetic particles stuck to the resin, namely, the core material of the carrier is composed of the resin and preferably a thermoplastic resin such as an acrylic resin and a nylon resin, etc., and the outer layer of the carrier is formed by sticking the magnetic particles on the surface of the resin, followed by forming a magnetic particle layer on the surface layer or in the inner part of the resin by thermally treating the resin. Accordingly, the magnetic particles having prescribed magnetic characteristics are used for the carrier for a magnetic brush developing agent, and the carrier forming material capable of freely changing the magnetic characteristics is produced by changing the thickness of a magnetic particle layer. And, the magnetic particle layer composed of the multilayer films having different kinds of the magnetic particles respectively is formed by using the various kinds of the magnetic particles for the magnetic particle layer. Thus, the obtd. carrier has a small bulk density and namely is made a light weight, and has the long shelf-life and is capable of giving the excellent picture quality.