| 摘要 |
PURPOSE:To obtain a magnetic toner giving a clear copy at all times without causing sticking to a sleeve even after carrying out continuous copying many times by sticking fine powders of SiO2 and ZnO to the surfaces of particles contg. a magnetic body and a binder as principal components. CONSTITUTION:Toner particles contg. a binder resin such as a styreneacrylic copolymer, an ethylene-vinyl acetate copolymer or polyethylene wax and magnetic powder as principal components and further contg. an electric charge controller, carbon, etc. are prepd., and the toner particles are mixed with 0.2-2.0wt% SiO2 of 10-20mmu primary particle size after making the surface of the SiO2 hydrophobic by a chemical method to stick the SiO2 to the surfaces of the toner particles. The particles are then mixed with ZnO powder such as commercially available ZnO powder to stick 0.5-3.0% ZnO to the surfaces of the particles. Thus, a one-component type magnetic toner for negative charge is obtd. Electric charges accumulated in the toner are properly leaked, so a clear image is formed at all time while preventing the sticking of the toner to a sleeve and the reduction of the flowability without reducing the image density. |
