| 摘要 |
PURPOSE: To prolong the service life of a developer by feeding the adding developer containing at least carrier particles and toner particles to the developer inside a developing device. CONSTITUTION: In this developing device 18, the developer 64 is discharged by being controlled by a permanent magnet 80 and the electric magnet 82 arranged in the vicinity of an outlet port 74 of the developing device 18. The developer curtain for preventing the developer 64 from flowing out from an outlet port is formed by the permanent magnet 80 capable of generating the magnetic flux's field on an area of the outlet port 74. When the electric magnet 82 is energized by the generated magnetic flux's field, the developer is attracted from the developer curtain. By demagnetizing the electric magnet 82, the attracted developer is released therefrom. |
