| 摘要 |
PROBLEM TO BE SOLVED: To perfectly recover developer in a developing tank without scattering the developer by making the intensity of magnetic field in the tangential direction of the surface of a sleeve opposed to the downstream end of the opening of the developing tank lower than that on the upstream side and the downstream side of the surface of the sleeve. SOLUTION: The intensity of magnetic field in the tangential direction at the most proximate position on the surface of the sleeve 14 is set to be lower than the intensity of the magnetic field on the upstream side. Thus, the magnetic field acts on the developer in a direction shown by an arrow. On the downstream side of an opening 23, the thickness of the napping of the developer in a radial direction on the surface of the sleeve 14 near the most proximate position of the sleeve 14 becomes smaller than that before and behind the position, and impact force by the developer is reduced. Then, the intensity of the magnetic field in the tangential direction thereat is set lower then the intensity of the magnetic field on the downstream side. Thus, carrying force is increased by a carrying magnetic pole B even after the developer is carried in the developing tank 16. Therefore, a situation that the developer is retained in the developing tank 16 near the most proximate position and the pressure of the developer is increased is prevented and the back flow of air from the aperture 23 is prevented. |
