Patent ID: 7835656

Claim:
A developing device comprising: a developer carrier that is rotated while holding a developer on a surface; a first housing chamber that houses the developer to be supplied to the developer carrier; a second housing chamber that has a bottom face that is lower than a bottom face of the first housing chamber in a gravitational direction; a first inflow portion that allows the developer to flow from the second housing chamber into the first housing chamber; a first conveying member that is provided in the first housing chamber, and that conveys the developer in the first housing chamber; a second conveying member that is provided in the second housing chamber, and that conveys the developer in the second housing chamber in a second conveying direction directed toward the first inflow portion; and a concentration detecting member that is provided in the bottom face of the second housing chamber upstream from the first inflow portion in the second conveying direction, and that detects a concentration of the developer housed in the second housing chamber, wherein: the second conveying member includes: a stirring member which opposes the concentration detecting member, and that stirs the developer in a circumferential direction of the stirring member by making a first conveying force in the circumferential direction greater than a second conveying force in an axial direction of the stirring member, the second housing chamber includes: an inner wall face; a region of the inner wall face which opposes the first inflow portion, and that is formed into a shape extending along an outer shape of the second conveying member; and a recess that is provided in a region of the inner wall face which opposes the concentration detecting member, and in which a sectional area of the region opposed to the concentration detecting member and perpendicular to the second conveying direction is larger than a sectional area of the region opposed to the first inflow portion and perpendicular to the second conveying direction, and wherein a part of the inner wall face of the second housing chamber, including the region where the concentration detecting member is provided, is projected from the region of the inner wall face opposed to the first inflow portion.