| 摘要 |
PROBLEM TO BE SOLVED: To realize a configuration in which, when a development sleeve 8 having a plurality of grooves is used in a configuration in which the percentage of the magnetism carrying power of a developer in the vicinity of a regulatory blade 9 is increased, it is possible to suppress the carried amount of the developer by the development sleeve 8 from becoming uneven.SOLUTION: Assuming that a value derived by integrating a magnetic force Fr in the normal direction of a development sleeve 8 from a regulatory blade 9 to a 2 mm upstream position regarding the rotation direction of the development sleeve 8 is FrNear, and a sum total of Fr derived by integrating Fr from the rear end of a guide member 11 to the regulatory blade 9 regarding the rotation direction of the development sleeve 8 is FrAll, then a plurality of magnetic poles of a magnet 8a are formed so that FrNear relative to FrAll is at least 60% or more. The grooves on the outer circumferential surface of the development sleeve 8 are formed so that multiple instances of it are present in an interval from the regulator blade 9 to a 2 mm upstream position irrespective of the position in the rotation direction of the development sleeve 8. |
