| 摘要 |
PURPOSE:To enhance durability of a developer, and to prevent fog even after successive copying and deterioration of image density by using a developer composed of a carrier coated with a resin contg. a fine ferroelectric powder, and a toner contg. a fine conductive powder. CONSTITUTION:A resin-coated carrier is obtained by mixing 0.1-10pts.wt. of a fine powder of ferroelectric, such as Ba titanate, with 100pts.wt. of a coating resin, such as silicone varnish, in toluene, and spraying over the surfaces of carrier iron particles using a circulating fluidized bed, tc., and then, thermosetting the resin. A total amt. of the coating resin and the fine powder is about 105g per 1kg of the carrier particles. A toner is prepared by incorporating 0.1- 30pts.wt. of a fine conductive powder of metal, SnO2, ZnO, or the like together with a necessary pigment, etc. in 100pts.wt. of a binder resin. A good quality image unchanged from the image formed at the start even after several hundred thousand cycles of successive copying by combining such a carrier with such a toner. |
