| 摘要 |
PROBLEM TO BE SOLVED: To keep a gap between the peripheries of a developing roller and a photoreceptor drum constant and to control a D-S distance with high accuracy by composing one of the nondeveloping regions of the photoreceptor drum and DS rollers of a magnetic material and the others of magnets. SOLUTION: DS rollers 52 consist of magnets constituted so that on the peripheries of the DS rollers 52, N- and S-poles are alternately arranged. A photoreceptor drum 6 is provided with a developing region 61 in which a photoreceptor layer is formed on a drum pipe stock made of aluminum etc., and nondeveloping regions 62 coming into contact with the DS rollers 52. The nondeveloping regions 62 are made of magnetic materials and come into contact with the DS rollers 52 to be in close contact states by the magnetic force of the DS rollers 52. Therefore, a gap between the peripheries of the developing roller 50 and the drum 6 can be kept constant. Further, it can be prevented that the roller 50 generates obliquely the positional deviation for the longitudinal direction of the roller 50 can be prevented and the fluctuation of the D-S distance during operation can be prevented as well. |
