| 摘要 |
PURPOSE:To reduce nonuniformities in the image density and to reduce the size and weight of the device by modulating the AC voltage in timing with passage of the projections and recesses of the developing medium through the developing area of the static latent image carrier such that the AC amplitude at the time of passing through the recesses becomes larger than that at the time of passing through the projecting portion. CONSTITUTION:The developing medium 5 including magnetic powders carried on the surface of a rotatable developing sleeve 4 forms projections and recesses as a function of the pole position of a rotating magnetic roll 3 mounted within the roll 1. With rotation of the developing sleeve and the magnetic roll, the projections and recesses of the developing medium make the round of the developing sleeve to pass over the development area 10 of the latent image carrier. The passing timing of these projections and recesses is sensed by magnetic position sensing means 7 and the resulting signals are used in the control means 11 to control an AC source 8 so that the amplitude of the AC voltage applied to the developing sleeve 4 is larger at the time of passing of the recesses of the developing medium than at the time of passing of the projections of the medium. The AC voltage applied to the developing sleeve is superimposed by a DC bias applied from a DC source. |
