| 摘要 |
A pressing wall is provided in a part of the entire area of the first carrying chamber in which a first screw member is housed. The area is opposed to a bottom wall of the first carrying chamber on the lower side in the gravity direction of the first screw member and opposed to the side walls of the first carrying chamber on both lateral sides orthogonal to a rotation axis direction of the first screw member. In the area, a toner concentration of a K developer being carried is detected by a K toner concentration sensor. The pressing wall comes into contact with, from above in the gravity direction, the K developer, which moves from a lower side to an upper side in the gravity direction according to the rotation of the first screw member, and presses the K developer downward in the gravity direction. |
