Patent ID: 8515316

Claim:
A developing device comprising: a developing unit configured to visualize an electrostatic latent image formed on a latent image support member using a developer that contains toner and carrier, the developing unit including a developer supply part and a developer collecting part; and a circulation path configured to collect the developer from the developing unit and feed the collected developer to the developer supply part, the circulation path including a reservoir provided before the developing unit to store and stir the developer, wherein the developing supply part has a developer inlet port configured to introduce the developer supplied from the reservoir into the developing supply part and a developer extraction port provided on a side of the developer inlet port to remove a portion of the developer to define a quantity of developer to be introduced to the developer supply part, wherein the developer extraction port has an area size that removes a quantity of extracted developer, the quantity of extracted developer being less than a quantity of developer fed to a developer feeding member provided in the developer supply part at a feed start position of the developer feeding member, wherein the developer extraction port is structured as an opening overlapping the feed start position of the developer feeding member.