| 摘要 |
PURPOSE:To prevent color mixing and take a polychromatic copy with high image density by performing electrostatic charging so that a toner image at a necessary color part has a charge of the same polarity with toner and a toner image at an unnecessary color part has a charge of the opposite polarity, and transferring the toner image at the necessary part selectively and electrostatically. CONSTITUTION:An electrostatic latent image which has a necessary and an unnecessary color part is developed in a developing stage. A photosensitive body which has a toner image formed at the necessary and unnecessary color parts is charged electrostatically prior to transfer. In this stage, toner at the necessary color part is given a charge of the same polarity with the toner and toner at the unnecessary color part is given a charge of the opposite polarity. Toner operating on toner in a transfer charge during transfer increases for the toner at the necessary color part and decreases for the toner at the unnecessary color part, thereby transferring the necessary color part selectively. Consequently, the transfer rate of the necessary color part is increased while the transfer of the unnecessary color part is prevented, and color mixing to the unnecessary color part in a blue color separation copy cycle is prevented, thereby improving image density. |
