Patent ID: 7953350

Claim:
A developing device, comprising: a development part configured to develop a latent image to a toner image, the development part including a development roller and a conveyor configured to convey developer, the developer comprising toner particles and carrier particles; an agitation part provided separately from the development part and configured to agitate the developer and receive replenished toner particles; and a controller configured to increase an agitation strength of the agitation part when an amount of replenished toner particles received by the agitation part is greater than a predetermined threshold value, and decrease the strength of the agitation part when an amount of replenished toner particles received by the agitation part is less than the predetermined threshold value, wherein the agitation part includes a toner injection opening through which toner injection opening the agitation part receives toner; a developer injection opening, separate from the toner injection opening, through which developer injection opening the agitation part receives developer from the development part; and a developer ejection opening through which developer ejection opening the agitation part discharges developer comprising a mixture of toner received through the toner injection opening and developer received through the developer injection opening.