DEVELOPING DEVICE OF ELECTRONIC COPYING MACHINE

PURPOSE:To prevent a tonner from scattering or leaking to the grounding part of photoreceptor when a latent image of the photoreceptor is developed by means of a magnetic roll, by providing an insulating elastic member which can have a close contact with the photoreceptor at the position which is further outside than the maximum image forming width of the photoreceptor. CONSTITUTION:A magnet roll 6 containing a permanent magnet is set between the insulating side plates 1 and 2. Then an insulating elastic matter 12 and a member 13 of a low friction coefficient are provided at the position further outside than the maximum image forming width of a photoreceptor 8. The fluororubber, porous quadrivant polyethylene fluoride, etc. are used to the members 12 and 13. When the photoreceptor 8 is set to a developing device, the roll touches the magnet roll 6 and is turned. The matter 12 contracts by the pressure and is turned into a low frictional force. Thus the load torque is reduced. Furthermore the scattering is prevented for the toner or the developer, and the leakage of the photoreceptor 8 is eliminated to the earth.