| 摘要 |
PURPOSE:To prevent decrease of image density and increase of fog by preparing a developer composed of a toner powder, and a fine powder having an average particle diameter smaller than that of the toner, and a particle diameter distribution contg. most of its particles within 0.1-0.5mum particle diameter. CONSTITUTION:A developer is prepared by mixing a toner powder made of polystyrene, PE, PP, or the like, and having an average particle diameter of 3- 20mum, with a fine polymer powder having an average particle diameter smaller than that of the toner, and a particle diameter distribution contg. most of the particles within 0.1-0.5mum, preferably amounting to >=90% of the total number of the particles, and incorporating this mixture in the developer. Polymers obtained by various kinds of polymn. methods can be used for said fine polymer powder, but the polymer obtained by the soap-free emulsion polymn. method is most suitable. It is added to the toner in 0.01-10wt%, preferably, 0.05-2.0wt%. |
