| 摘要 |
PURPOSE:To improve a picture quality by a simple mechanism, by switching the alternate voltage at the time of development and at the time of non-development, and enlarging a reverse transfer electric field for drawing back a toner to a developer carrying body from an image holding body, at the time of non- development. CONSTITUTION:A circuit for varying the alternate voltage consists of two AC power sources 5, 6, and a DC portion of the alternate voltage is made variable by making the power source 6 variable as to its voltage. At the time of non- development, it is connected to an alternate voltage power source 19 by a signal from a sequence controller 7, varies the alternate voltage greatly through a controlling circuit 20 containing an alternate voltage varying circuit, and controls the developing operation. That is to say, the transfer electric field is made small, and the reverse transfer electric field is enlarged. Also, at the time of development, the potential of a latent image and the picture density corresponding to taste of an operator are obtained by adjusting an aperture dial through the controlling circuit 20. In this way, a quality of a picture can be improved by a simple mechanism. |
