Patent ID: 7904001
Filing Date: 2011-03-08
Classification: G03G

Abstract:
1. A developing unit containing a developer including a carrier and a toner, and developing a latent image formed on an image carrier, the developing unit comprising: a plurality of conveyor members configured to convey the contained developer in respective longitudinal directions so as to form a circulation channel; a supply part configured to supplement the carrier in the developing unit; a discharge part configured to discharge a first part of the contained developer to outside of the developing unit; and a bypass channel configured to cause a second part of the developer to return to an upstream side of the circulation channel without passing a position where the discharge part is provided, wherein: the discharge part includes a discharge opening for discharging the first part of the developer in response to a surface of the developer conveyed to a position of the discharge opening exceeding a predetermined first height; the bypass channel includes an opening for guiding the second part of the developer to the bypass channel in response to the surface of the developer conveyed to a position of the opening exceeding a predetermined second height; the opening is provided on an upstream side of the discharge opening in the circulation channel; and a lower part of the opening is positioned higher than a lower part of the discharge opening.