| 摘要 |
PURPOSE:To obtain high fidelity and excellent and stable picture quality by using toner which has a specific degree of flocculation and magnetic particles which have a specific grain size distribution. CONSTITUTION:A developer container 3 for the storage of the toner 4 and magnetic particles 5, a sleeve 2 which conveys the toner 4 to a photosensitive drum 1, and a magnet 7 which forms a magnetic brush of the magnetic particles 5 contacting the sleeve 2 at the upstream side of the toner exit of the container 3 to form a thin layer of the toner 4 on the sleeve 2. In this case, the toner in use has a <=30% degree of flocculation at 25 deg.C temperature and 60% relative humidity and is <=1.2 in real specific gravity, and >=70 piece % of all particles are contained within + or -20% of mean grain size gamma. Those toner 4 and magnetic particles 5 are used to control the coating state of toner on the sleeve 2 precisely, and the toner is applied uniformly over a photosensitive drum 1 to obtain an excellent development state. This state is maintained regardless of temperature and humidity and even if an image is left for a long period to obtain a clear and stable image with high fidelity. |
