| 摘要 |
PURPOSE:To improve filming resistance by incorporating fine silica powder synthesized by a dry process, having a specified bulk density and treated with a silane coupling agent and/or silicone oil. CONSTITUTION:Fine silica powder synthesized by a dry process, having <=35 g/l bulk density and treated with a silane coupling agent and/or silicone oil is incorporated. When the fine silica powder is mixed with a toner in a dry mixer to obtain a developer, an aggregate of primary particles of the fine silica powder and a lump of such aggregates are not formed in the developer and the fine silica powder disperses and sticks uniformly and tightly on the surface of the toner. The fine silica powder in the developer does not stick or deposit on a photosensitive body even when the developer is used over a long period of time and filming resistance is improved. |
