Abstract: A developing device for use in an image forming apparatus, the developing device including a dispersion-preventing plate extending from an outlet of a toner hopper near to an upper portion of a stirrer, and/or a stirrer provided with blades radially fixed to its rotary axis and spiral screws alternately in the axis direction.

Abstract: The object is to carry out developer feeding and toner supplement in a short time without scattering dust particles around, in view of the effectual use of natural resources and space saving. A developer cartridge is removably mounted on a developing unit body and also functions as a lid for closing a developer supply opening after developer has been released into the developing unit body. A toner cartridge includes a lid which can be inserted into and taken out of a toner cartridge body; a sealing member for sealing the toner release opening of the toner cartridge body, the leading edge of which is fixedly attached to the end of the lid on a side from which the lid is inserted; and a tab sheet one end of which is fixed to the middle position of the sealing member and the other end of which is temporarily affixed to the lid.