| 摘要 |
PURPOSE:To form stably a sharp image having high density without fogging for a long period of time in image formation including a stage for developing the latent image of a carrying body by using a toner at a ratio within a specific range with a carrier when the average grain size and true specific gravity of the toner and carrier are specified to prescribed values. CONSTITUTION:The toner concn. Tc of the two-component developer, i.e., the ratio (wt%) of the content of the toner with respect to the carrier is maintained within the range shown by the formula where the average grain size of the toner is designated as r1mum, the average grain size of the carrier as r2mum, the true specific gravity of the toner as rho1 and the true specific gravity of the carrier as rho2. The carrier consists of the particle powder which is formed by dispersing and incorporating the pulverous powder of a magnetic material into a binder resin such as styrene or vinyl ketone and has 10-50mum average grain size. Metals such as iron and cobalt including ferrite and magnetite exhibiting strong magnetisum or the alloy thereof, etc. are used for the magnetic material used for the pulverous powder of the magnetic material. The average grain size of the pulverous powder of the magnetic material is about 0.05-3mum and the ratio of te content of the pulverous magnetic material powder is 40-90wt% by the weight of the carrier. |
