| 摘要 |
PURPOSE:To provide a developing device capable of reducing degradation due to the use of a developer, sufficiently electrifying developer and obtaining a high quality image. CONSTITUTION:In a magnet roller 13 in a developing sleeve 3, the densities of the magnetic fluxes of magnetic poles for carrying S2 and n2 corresponding to a carrying area from a position where the developer is supplied onto the developing sleeve 3 and carried to a bristle cutting position, are made low into 10-49% of that of a developing pole N1 and an auxiliary electrifying screw 18 is provided. Therefore, the densities of the magnetic fluxes of the magnetic poles S2 and N2 are made low so that the density on the retaining part 5 of the developer magnetically restricted on the sleeve 3 is set low to reduce compressing force, the degradation of the developer is lessened and moreover, the deficient electrification of the developer because of the densities are made low is auxiliary electrified, so that the developer is sufficiently electrified. |
