Developing device

Abstract

Abstract PURPOSE:To form a thin layer of nonmagnetic toner easily and to facilitate normal development and reversal development, by separating and sticking only toner to the surface of a rotating body, and impressing a positive or negative source voltage between the rotating body and a developer supporting means selectively. CONSTITUTION:The movable contact of a switch is switched to the fixed contact in reversal development mode. Consequently, an electric field (voltage) reverse of that during normal development, e.g. 400-500V is impressed between a developing roll and a nonmagnetic cylindrical sleeve, i.e. a carrier and toner. The toner in a developer is stuck to the developing roll by the rotation of the cylindrical sleeve to form the toner layer. The potential of the toner layer attains to about 40V and an AC bias is deviated to the positive side by 200-500V to invert the electrification polarity of the toner to a level enough for the reversal development. A photosensitive drum 2 slides on the thin layer of the positively electrified toner in contact to carry out the reversal development.

Inventors

• 👤 Mitsuaki Kamiyama
• 👤 神山　三明

Bibliographic Details