Image forming apparatus and image forming method having three agitating and conveying elements for toner in a developing unit

摘要

A developing unit (5) has first and second partition walls (14) and (15) which divide the inside of a developer reservoir (11) into first to third chambers (16 - 18) parallel to the developing roller (12), and first to third mixers (20 - 22) which are disposed in the first to third chambers (16 - 18). The first mixer (20) supplies developer to the developing roller (12) by stirring and carrying from one end side to the other end side. The second mixer (21) feeds by stirring and carrying the toner replenished from a replenish device (8) and developer fed from the first chamber (16) to one end side of the first mixer (20). The third mixer (20) feeds the toner collected from a collection mechanism (10) to one end side of the first mixer (20) by stirring and carrying at a speed lower than the second mixer (21). <IMAGE>