A toner container according to one example embodiment includes a housing having a reservoir for holding toner and a rotatable auger in the reservoir. A screw flight of the auger is configured to move toner away from a first end of the auger and toward a second end of the auger when the auger rotates in an operative rotational direction. A segment of the screw flight at a first end of the screw flight has an outer diameter that is reduced in comparison with an outer diameter of the screw flight outside the segment of the screw flight to reduce an efficiency of the auger at the first end of the screw flight for reducing toner packing against an interior wall of the housing when the auger rotates in a direction counter to the operative rotational direction.

Toner replenishment units include an upper toner container, a lower toner container, a first vertical conveyance pipe, a second vertical conveyance pipe, a third vertical conveyance pipe, a first horizontal conveyance pipe, a second horizontal conveyance pipe, and a confluence section. A first conveyance screw is included in the horizontal conveyance pipe and a second conveyance screw is included in the second horizontal conveyance pipe. A first inter-axis distance between a first horizontal rotation axis of the first conveyance screw and a third vertical pipe axis of the third vertical conveyance pipe, and a second inter-axis distance between a second horizontal rotation axis of the second conveyance screw and the third vertical pipe axis are set to take a different value.

An imaging system includes a developing roller connected to a supply channel to supply a developing agent and to transfer toner in the developing agent to a photosensitive drum at a supply position, a regulation member located adjacent to the developing roller at an upstream side of the supply position to restrict a thickness of the developing agent; and a casing that forms a release chamber in the periphery of the developing roller between an upstream side of the regulation member and a downstream side of the supply position. The release chamber includes an outlet to discharge scattered toner to an inlet of the supply channel.

Toner replenishment units include an upper toner container, a lower toner container, a first vertical conveyance pipe, a second vertical conveyance pipe, a third vertical conveyance pipe, a first horizontal conveyance pipe, a second horizontal conveyance pipe, and a confluence section. A first conveyance screw is included in the horizontal conveyance pipe and a second conveyance screw is included in the second horizontal conveyance pipe. A first inter-axis distance between a first horizontal rotation axis of the first conveyance screw and a third vertical pipe axis of the third vertical conveyance pipe, and a second inter-axis distance between a second horizontal rotation axis of the second conveyance screw and the third vertical pipe axis are set to take a different value.

A toner cartridge includes a first casing, a second casing, an auger screw, and a shutter. The first casing has a first internal space. The second casing has: a second internal space smaller than the first internal space; a first opening allowing toner in the second internal space to be discharged; and a second opening allowing air in the second internal space to be sent to an outside. The auger screw is rotatable about a first rotation axis and configured to convey toner in the first internal space to the second internal space. The shutter is rotatable relative to the second casing about a second rotation axis between a first position in which the shutter closes the first opening and a second position in which the shutter opens the first opening. In a state where the shutter is at the second position, the shutter does not close the second opening.

A waste powder recovery device includes: a recovery container that houses waste powder and has an inlet through which the waste powder is received; and a conveying component that is cantilever-supported in such a way as to swing freely inside the recovery container, the conveying component having a first conveying section with which the waste powder brought in through the inlet is conveyed with a first conveying force within the recovery container, and a second conveying section with which the waste powder is conveyed with a second conveying force that is larger than the first conveying force.

An imaging system includes a developing roller connected to a supply channel to supply a developing agent and to transfer toner in the developing agent to a photosensitive drum at a supply position, a regulation member located adjacent to the developing roller at an upstream side of the supply position to restrict a thickness of the developing agent; and a casing that forms a release chamber in the periphery of the developing roller between an upstream side of the regulation member and a downstream side of the supply position. The release chamber includes an outlet to discharge scattered toner to an inlet of the supply channel.

A waste powder recovery device includes: a recovery container that houses waste powder and has an inlet through which the waste powder is received; and a conveying component that is cantilever-supported in such a way as to swing freely inside the recovery container, the conveying component having a first conveying section with which the waste powder brought in through the inlet is conveyed with a first conveying force within the recovery container, and a second conveying section with which the waste powder is conveyed with a second conveying force that is larger than the first conveying force.

An attachment and detachment structure attaches and detaches a toner container to and from an attachment unit. The toner container includes a container main body, a rotational member and a power transmission body. The rotational member rotates around an axis to agitate the toner contained in the container main body. The power transmission body is provided outside the container main body and rotates around an axis to transmit a rotational force to the rotational member. The attachment unit includes a contact body which comes into contact with the power transmission body on attachment process and detachment process of the toner container to and from the attachment unit and rotates the power transmission body. The power transmission body comes into contact with the contact body on the attachment process of the toner container to the attachment unit, and is rotated around the axis to rotate the rotational member around the axis.

According to a first aspect of the present invention, a developing apparatus includes a developer container, a conveyance screw, and an inductance sensor. The conveyance screw further comprises a rib, protruding in a radial direction from the shaft portion, provided at a position opposed to the inductance sensor, and a second blade portion provided continuously to an upstream end portion of the rib with respect to the conveyance direction and configured to convey the developer to the conveyance direction by rotation. The second blade portion is formed to extend not more than one-third of a turn from the upstream end portion of the rib downstream in a direction of rotation of the conveyance screw when viewed in an axial direction of the conveyance screw.