Entwicklungsvorrichtung

摘要

A developing device incorporating a developer supply unit and a developer discharge section, in which a supply developer including a mixture of toner and carrier is successively supplied to a developer container from the developer supply unit and a deteriorated developer in the developer container is discharged through the developer discharge section. The developer supply unit has a sponge roller for selectively attracting toner to a surface thereof, a magnet roller for selectively attracting carrier to a surface thereof, and a member for scraping and bringing the toner and carrier attracted to these rollers into the developer container. The developer including toner and carrier in a predetermined ratio is thus stably supplied to the developer container. In another example of the developer supply unit, agitating of the developer is performed while shovelling the developer deposited in a lower part of the unit by a transport screw. With this structure, since the toner and carrier are evenly mixed in the unit, the developer having a uniform toner concentration is supplied to the developer container, thereby continuing satisfactory development.