Patent ID: 8837991

Claim:
A developing device comprising: a developer bearing member bearing a developer including a toner and a carrier; a stirring and carrying unit carrying the developer in a first carrying direction while stirring the developer; and a supplying and carrying unit disposed above the stirring and carrying unit to supply the developer carried via a communication portion from the stirring and carrying unit to the developer bearing member while carrying the developer in a second carrying direction opposite to the first carrying direction, wherein the stirring and carrying unit comprises a rotational shaft; a first spiral wing formed on the rotational shaft to carry the developer in the first carrying direction; a second spiral wing positioned on the more downstream side in the first carrying direction than the first spiral wing and formed in a multi-spiral to carry the developer in the first carrying direction; and a third spiral wing positioned on the more downstream side in the first carrying direction than the second spiral wing and formed in a multi-spiral to carry the developer in the second carrying direction, wherein the second and third spiral wings are equal in number of spiral lines and lead, and are also equal in position of adjacent ends in a rotational direction, and the communication portion is installed at a position corresponding to the second and third spiral wings of the stirring and carrying unit.