Patent ID: 8731445

Claim:
A developing unit comprising: a developer container configured to contain developer; a developing section positioned adjacent to the developer container, the developing section comprising: a developer-bearing member configured to be rotatable and to bear developer; a supplying member configured to be rotatable and to supply the developer to the developer-bearing member; a conveying member configured to be rotatable, to convey the developer supplied from the developer container in an axial direction of the supplying member, and to return the developer to the developer container at a downstream end thereof; and a partitioning wall configured to reduce movement of the developer from the conveying member toward the developer-bearing member and positioned at the downstream end of the conveying member in a developer conveying direction parallel to the axial direction, positioned downstream of the supplying member in the developer conveying direction of the conveying member, wherein both a downstream-end portion of the conveying member in the developer conveying direction and a downstream-end portion of the developer bearing member in the developer conveying direction are extended axially outward with respect to the supplying member configured to supply the developer to the developer-bearing member, such that the partitioning wall is positioned between the downstream-end portion of the conveying member and the downstream-end portion of the developer-bearing member; and a partition wall positioned adjacent to the conveying member and configured to separate the developing section and the developer container, the partition wall having a supply port through which the developer is supplied from the developer container to the developing section and having a return port through which the developer is returned from the developing section to the developer container, wherein the return port faces the downstream-end portion of the conveying member.