| 摘要 |
PURPOSE:To form a sharp toner image stably by producing a unidirectional electric field in a development area previously and then varying the oscillating electric field continuously or stepwise before a latent image on an image carrier reaches the development area. CONSTITUTION:The surface of the photoconductor layer of the image carrier 3 which is rotated as shown by an arrow A and charged uniformly and electrostatically is exposed to an image by a laser beam scanner with a binary-coded signal, thus forming a latent image. A developing device has a developer carrier 15 of a nonmagnetic material applied with a bias voltage from a bias power source 11 to generate an electric field in the development area before the carrier whose base part is grounded. Before the latent image reaches the development area, the carrier is applied with a DC voltage previously and an AC voltage with a constant period is increased in amplitude gradually and superposed, so that the latent image formation area of the carrier 3 passes through the development arear when the amplitude of the AC voltage attain to a specific value. Thus, fog-free toner development is carried out without scattering toner. |
