| 摘要 |
PURPOSE:To eliminate the need for toner concentration control and preclude ground fogging, and to improve the image sharpness and gradations by supplying a developer to an image carrier in the presence of an alternating electric field applied between the image carrier and a sleeve and an alternating magnetic field produced by a magnet roll. CONSTITUTION:A sleeve 7 has the magnet roll 6, which has different-polarity magnetic poles S and N arrayed alternately, internally and attracts the developer consisting of high-resistance magnetic toner and magnetic carriers on its outer peripheral surface. Then the magnet roll 6 and sleeve 7 are rotated in the opposite direction from the rotating direction of the image carrier 1 to move the developer 4 in the same direction with the rotating direction of the sleeve 7 and the developer is supplied to the image carrier 1 in the presence of the alternating electric field applied between the image carrier 1 and sleeve 7 and the alternating magnetic field by the magnet roll 6 to perform development. Therefore, the developer 4 is vibrated by the synergetic effect between the alternating electric field and alternating magnetic field and attracted to electrostatic latent image potential places of the image carrier 1. Consequently, the need for toner concentration control is eliminated, ground fogging is precluded, and the image sharpness and gradations are improved. |
