| 摘要 |
PURPOSE:To obtain a developer for electrophotography by which an electrification quantity can be controlled appropriately, also an electrifying speed is high, and a stable electrifying property can be maintained extending over a long period of time, by making the developer contain a toner containing a partial fluorinated magnetic powder, or a carrier particle. CONSTITUTION:A magnetic powder of magnetite, etc. is immersed into a water solution of NH4F, and thereafter, dried up and burned in nitrogen by an electric furnace. Or the magnetic powder is brought to HF gas treatment, etc. by a fluid bed, and a partial fluorinated magnetic powder of 1-100wt% F content, such as that which has fluorinated the surface of the magnetic powder, that which has fluorinated the surface and the inside of the magnetic powder, etc. is used as a carrier. Also, the magnetic powder fluorinated by 20-80% is used as a toner. A partial fluoride in which an average particle diameter of the magnetic powder is large is used as a carrier as it is. That which has a small average particle diameter is dispersed into a binder, melted and mixed, and thereafter, crushed and classified, and used as a carrier. Also, in case of using the magnetic powder as a toner, it is mixed with the binder, melted and kneaded, and thereafter, crushed and dispersed, and it is obtained. In this way, a developer which is excellent in its electrification characteristic, weather resistance, fluidity, etc., and also stable extending over a long period of time is obtained as an electrostatic latent image developer. |
