A toner conveyance device includes a vertical conveyance portion, a horizontal conveyance portion, a conveyance member, and a loosening member. The vertical conveyance portion conveys a toner or developer conveyed therein through an entry port connected to a main-body-side conveyance path by causing the toner or developer to fall vertically. The horizontal conveyance portion is connected to a lower end of the vertical conveyance portion and conveys the toner or developer in a horizontal direction by using the conveyance member. the loosening member is arranged at a first position below a connection portion between the main-body-side conveyance path and the entry port and at a second position protruding upward beyond the connection portion. A toner loosening mode is executable in which the toner or developer is fed into the vertical conveyance portion so as to cause the loosening member to reciprocate at the second position.

A developing cartridge may include: a casing; a developing roller extending in a first direction; a developing-roller gear; a coupling including a coupling gear; a first idle gear; a second idle gear; an agitator; a first agitator gear; and a protrusion. The developing-roller gear, the coupling, the first idle gear, the second idle gear, the first agitator gear, and the protrusion may be positioned at an outer surface of the casing. The protrusion may be positioned between a first axis of the coupling and a third axis of the first agitator gear in a second direction connecting the first and third axes. The protrusion may be positioned outside an addendum circle of the developing-roller gear, an addendum circle of the coupling gear, an addendum circle of the first idle gear, and an addendum circle of the second idle gear. The first agitator gear may be spaced apart from the protrusion in the first direction.

Toner cartridge includes a housing, an agitator, an auger, a first protrusion, and a second protrusion. The housing includes a first toner accommodating portion having and a second toner accommodating portion. The auger is rotatable about a second axis extending in a first direction and is configured to convey toner from a first toner accommodating portion to the second toner accommodating portion. The first protrusion is positioned at a first side of the second toner accommodating portion. The first protrusion extends in the first direction. The second protrusion is positioned at a second side of the second toner accommodating portion and extends in the first direction.

An imaging system comprises a stirring-conveyance member to supply developer to a developing roller. The stirring-conveyance member includes a spiral structure to convey the developer and a reverse spiral structure disposed downstream the spiral structure in a conveying direction of the developer. The reverse spiral structure has a maximum outer diameter at an upstream end in the conveying direction and a minimum outer diameter at a downstream end in the conveying direction. The minimum outer diameter is approximately ⅗ or less, of the maximum outer diameter.

In an image forming apparatus, a drum cartridge includes a photosensitive drum, a developing device, a drum cleaner, a waste toner tube, and a flange. The waste toner tube includes a first end portion communicating with the drum cleaner and a second end portion connected to the flange. The developing device includes a protruding portion facing the flange. The cushion member is located between the flange and the protruding portion. The cushion member allows a cartridge mounting part of the developing device to move with respect to the flange in a case where the developing device moves with respect to the photosensitive drum.

A first development chamber accommodates an agitator. A second development chamber accommodates a development roller and a supply roller. The second development chamber is located above the first development chamber. A toner cartridge contains toner to be supplied to the first development chamber. A transfer device is located above a photosensitive drum in a state where a drum unit is attached to a main housing. The transfer device transfers toner on the photosensitive drum to a sheet. An agitator includes a shaft and a blade. The shaft is rotatably supported by a development housing. The blade is rotatable together with the shaft. The blade has a first end fixed to the shaft and a second end located away from the first end. The agitator is configured such that, when rotated, the second end of the blade reaches a height of an opening in the development housing in a vertical direction.

A developing apparatus includes a replenishment conveyance screw portion to convey replenishment developer from a developer replenishment portion toward a first communication portion. First, second and third blade portions are formed in a spiral shape on an outer circumferential surface of a rotation shaft of the replenishment conveyance screw portion. A pitch of the first blade portion, a pitch of the second blade portion, and a pitch of the third blade portion are each larger than a pitch of a blade of a second conveyance screw portion, and the third blade portion is continuously formed in a region between a terminal end of the first blade portion and a starting end of the second blade portion.

In a cartridge, a housing has a developer accommodating portion and includes a first side wall and a second side wall. A coupling member is disposed at a position opposite to the developer accommodating portion with respect to the first side wall. A detection body is disposed at a position opposite to the developer accommodating portion with respect to the second side wall. A first driving force transmission member is positioned at the same side with the coupling member with respect to the first side wall, and transmits driving force from the coupling member to a rotating member. A second driving force transmission member is positioned at the same side with the detection body with respect to the second side wall, and transmits driving force from the rotating member to the detection body.

An apparatus includes an image bearing member, a developer container having a replenishment port, a developer bearing member, a detection portion configured to output remainder amount information corresponding to the amount of developer accommodated in the developer container, a notification portion capable of notifying a first state, and a second state, and a control portion. The maximum amount of the developer that the developer container is capable of accommodating is larger than a value obtained by adding the amount of the developer accommodated in a replenishment container containing the developer for replenishment to the first amount, and wherein notification of the second state corresponds to notification of a case where the amount of the developer remaining in the developer container is larger than a case where the amount of the developer remaining in the developer container is the smallest.

A developing device includes a developing container having a first stirring chamber and a second stirring chamber that are arranged in juxtaposition with each other and a developer carrier that carries toner in the second stirring chamber. The developing container includes a duct, an air suction port, a first filter, and a second filter. The duct is arranged adjacently to the second stirring chamber and allows air in the second stirring chamber to flow out to an exterior. The air suction port is open along a longitudinal direction of the second stirring chamber and allows communication between inside the second stirring chamber and inside the duct. The first filter covers the air suction port. The second filter is arranged on a downstream side of the first filter in an air circulation direction in the duct and covers an air circulation path in the duct.