Developing device for preventing thickening of the developer at both ends of a sleeve

摘要

In a developing device according to the present invention, a developing roller 8 has a fixed shaft 12 and a sleeve 13. The length of a draw-up magnetic pole N3 provided in the fixed shaft 12 is made shorter than the length of a main magnetic pole N1. Accordingly, the amount of a developer adhering to both ends of an outer peripheral surface of the sleeve 13 is reduced, so that the density of the developer at both the ends of the sleeve 13 is maintained in suitable conditions in a state where the developer is over the main magnetic pole N1.