| 摘要 |
PURPOSE:To always stably supply a developing agent of a fixed concentration for development, by weakening the magnetic pole of a developing sleeve provided in the vicinity of the section of the sleeve opposing to a bristle height controlling member and strengthening the magnetic poles on both sides of the magnetic pole with different polarities. CONSTITUTION:Toner supplied to the surface of a developing sleeve 4 at the section opposing to a magnetic pole N3 is carried to the direction (b) together with the developing agent held by the sleeve 4 in accordance with the rotation of the sleeve 4. The developing agent is carried in a layered form along the line of magnetic force in the section from the magnetic pole N3 to another magnetic pole S2, but the magnetic brush is relatively raised up in the radial direction and the developing agent is carried in a sparse state during the section from the magnetic pole S2 to another magnetic pole N2. When the developing agent collides with a bristle height controlling member 6, the agent is largely curved upward and well mixed and stirred while it is diffused and, at the same time, the agent falls upon the sleeve 4 over a wide area. Therefore, the developing agent of fixed concentration can always be supplied to development in a stable state on the sleeve 4. As a result, the copied image becomes distinct and a high-quality copy which is excellent in reproducibility can be obtained. |
