DEVELOPING DEVICE AND PROCESS CARTRIDGE AND IMAGE FORMING DEVICE PROVIDED WITH THEM

摘要

A simple-construction developing device capable of good developing with tailing/front bleeding prevented. The maximum value FO of a magnetic attraction force in the vicinity of a main magnetic pole S1 out of magnetic poles formed by the magnetic field generating means (3) of a developing device (1) is positioned on the downstream side, in the rotation direction of a developing powder carrier (2), of a magnetic flux density peak position in the normal direction of the main magnetic pole S1, for example, at least 8˚ downstream side, in the rotation direction of a developing powder carrier, of a magnetic flux density peak position in the normal direction of the main magnetic pole S1, and the half width of the maximum value FO of the magnetic attraction force is small and peaky, for example, providing a distribution of up to 54˚.