| 摘要 |
PURPOSE:To obtain a high-quality image at low manufacturing cost through reduced manufacturing steps by using a carrier made of a fine magnetite powder composed essentially of Fe3O4. CONSTITUTION:The carrier to be used is made of a fine magnetite powder composed essentially of Fe3O4. The magnetite ore to be used for the carrier is sufficiently dressed, further pulverized, and classified to obtain a particle size distribution of 30-200mu, preferably, 50-150mu. It has an iron content of 60-70wt%, and it contains other oxides, such as SiO2, Al2O3, CaO, and MgO, and impurities in an amt. of <=10wt%. The obtained fine magnetite powder can be used for the carrier as it is, but it may be coated with a styrene-acrylate type polymer, a tetrafluoroethylene resin, or the like in order to improve compatibility with a toner. |
