| 摘要 |
PURPOSE:To eliminate the need for toner concentration control, to preclude ground fogging, and to improve the image sharpness and gradations by supplying high- resistance magnetic toner to a carrier layer, forming a magnetic brush on a sleeve, and developing an electrostatic image formed on the image carrier in the presence of an alternating electric current and an alternating magnetic field. CONSTITUTION:The high-resistance magnetic toner is supplied to the carrier layer formed previously on the peripheral surface of the sleeve 7 which has a magnet roll 6 internally to form the developer brush on the sleeve 7, and the electrostatic latent image formed on the image carrier 1 is developed with the developer brush in the presence of the alternating electric field and alternating magnetic field. The toner is therefore vibrated by the synergistic effect between the alternating electric field and alternating magnetic field and attracted to electrostatic latent image potential places on the image carrier 1. Further, the carrier layer is formed to give the friction charge to the high-resistance magnetic toner, which sticks on the electrostatic image; and carriers which are only enough to form the carrier layer on the sleeve 7 are required. Consequently, the need for toner concentration control is eliminated, the ground fogging is precluded, and the image sharpness and gradations are improved. |
