| 摘要 |
PROBLEM TO BE SOLVED: To provide a developing device that stably charges toner over a long period of time, in a hybrid developing type system. SOLUTION: The developing device includes a first transport member 54, which holds and conveys a developer 2 on the surface thereof; two or more second transport members 48a and 48b, which hold and convey toner on the surface thereof. In a rotational direction of an electrostatic latent image carrier 12, the rotational directions of the second transport members 48a and 48b at the uppermost stream side and the lowermost downstream side, in an opposing section to the electrostatic latent image carrier are each in the same direction as that of the electrostatic latent image carrier, and the rotational direction 54 of the first transport member in an opposing section to the second transport member 48b at the most downstream side is in the opposite direction to the second transport member at the lowermost downstream side. A developer includes 0.1-3 pts.wt. of particles with reverse polarity, which are charged in the polarity reverse to the charge polarity of the toner due to frictional contact with a carrier, based on 100 pts.wt. of a toner base material, and the residual ratio of the particles with reverse polarity remained on a surface of the toner base material when ultrasonic waves are applied for 5 minutes in water is 60-90%. COPYRIGHT: (C)2011,JPO&INPIT |
