| 摘要 |
PURPOSE:To obtain a good image even in high speed copying, by developing an electrostatic latent image using a developer comprising a toner, and magnetic particles having average particle diameter, electric resistance, magnetization, etc. in specified regions, and capable of charging the toner to a prescribed polarity. CONSTITUTION:The magnetic particles are prepd. by melting and kneading an insulating resin, such as polyethylene or polyacrylate, a fine magnetic powder, such as gamma-Fe2O3, ferrite, or magnetite, and a resistance controller, such as carbon black, followed by cooling, hardening, finely pulverizing, and classifying. The obtd. magnetic particles have 18-70mum average particle diameter, 10<8>- 10<12>OMEGA.cm resistivity, and >=1,200 gauss in a 1,000 oersted magnetic field. This magnetic particles are mixed with a toner and stirred to generate triboelectricity in the toner to a polarity suitable for development, and the electrostatic latent image formed on the surface of an electrostatic latent image bearing material is visualized by using this obtd. developer. |
