| 摘要 |
PURPOSE:To prevent base-soiling and simultaneously to improve sharpness by specifying the ratio of the volume average grain diameter of a developer and a number average grain diameter, and dielectric constant, and simultaneously incorporating a fine powder addition agent having different grain diameters. CONSTITUTION:The developer used for this developing device is a one- component developer that the ratio DP/DV of the volume average grain diameter DV and the number average grain diameter DP is >=0.8, and the dielectric constant is <=3, and the fine powder addition agent having different grain diameters is incorporated. In other words, fixing properties are not inhibited by the mixing of the fine powder addition agent having different grain diameters. Besides, the contact distance of a latent image carrier and toner can be properly kept away, and the developer having small dielectric constant is used, so that a charge is not easily injected and the influence of an electric field is evaded. The ratio DP/DV of the grain diameter is selected and the distribution of the grain diameter of the toner is sharpened, so that an adverse effect by a blade part is evaded. Thus, the occurrence of the base-soiling is prevented, and the sharpness of an image is improved. |
