Patent ID: 7558513

Claim:
A developing device for supplying developer particles to a peripheral surface of an image bearing member comprising: a housing; a circulating passage for conveying developer particles while stirring them, the circulating passage being provided in the housing; a developer supplier for supplying developer particles in the housing; a developer inlet section for allowing developer particles to come in from the developer supplier, the developer inlet section being formed in an upper portion of the housing; a conveyance mechanism for conveying developer particles received through the developer inlet section, the conveyance mechanism being provided in the circulating passage; and a developing roller provided at a position of facing the image bearing member, wherein: the circulating passage includes a front conveyance passage extending along the developing roller, and a rear conveyance passage extending parallel to the front conveyance passage and passing a position to receive developer particles from the developer inlet section, the conveyance mechanism includes a front conveyer and a rear conveyer which are rotatable about their respective axes to convey developer particles in specified conveyance directions, the front conveyer being provided in the front conveyance passage and the rear conveyer being provided in the rear conveyance passage, the rear conveyer having a conveyance power reduction portion for reducing the conveyance power locally, and the developer inlet section includes a first developer inlet opening for allowing developer particles from the developer supplier to come in, and a second developer inlet opening for allowing developer particles recovered from the image bearing member to come in, the first and second developer inlet openings being provided in the circulating passage at locations which are on upstream of the conveyance power reduction portion of the rear conveyer and where developer particles coming from the first developer inlet opening and/or the second developer inlet opening are likely to be upwardly surged due to the rotation of the rear conveyer.