In a developing device for an image forming apparatus of the present invention, use is made of a magnetic molding produced by compression-molding a magnet compound material in a magnetic field. The polymeric developer accelerator is preferably a phenolic formaldehyde resin comprising at least 70 mol % of meta-cresol as recurring unit or at least 40 mol % of monohydroxy benzene cresol as recurring unit. The tool can be made of one material, and it is preferably rigid throughout its entirety and presents a handle for maneuvering the tool in its multi-functions. In one embodiment, the insert may also include an extended nose region.