| 摘要 |
PROBLEM TO BE SOLVED: To provide a developing device capable of preventing the occurrence of development unevenness corresponding to a magnetic pole pitch at the time of attaining development by using a developing roller consisting of a sleeveless magnet roll having plural magnetic poles. SOLUTION: A covering layer 12 made of a soft magnetic material is formed to cover the surface of a magnet roll, at least in the part corresponding to a latent image of a multimagnetic pole developing roller 2, that is, the region of an image forming width W of the multimagnetic pole developing roller 2 for actualizing the latent image on a photoreceptor drum 1. Thus, the degree of the short circuit of the line of magnetic force between the adjacent magnetic poles of the developing roller 2 is increased, a magnetic flux leaking in the part corresponding to the magnetic pole of the developing roller 2 is reduced and the napping height hH of a magnetic developer 4 at the center of the magnetic pole is suppressed to be the same as the napping height hL of the magnetic developer 4 in the part corresponding to the space between the magnetic poles, to eliminate the occurrence of the development unevenness. |
