An image forming apparatus includes a developer container to and from which a replenishment container is attachable and detachable and which includes an accommodating portion that accommodates developer and a replenishment port, an agitation member, an opening/closing member configured to be movable between a closed position and an open position, a drive source for driving the agitation member, and a control portion configured to control the drive source. The apparatus is configured such that image formation is not possible when the opening/closing member is at the open position, and the agitation member is capable of driving in a case where the opening/closing member is at the open position.

A toner cartridge includes a toner accommodation chamber containing toner, a toner discharging chamber having a discharge opening for discharging the toner, and a passage for fluid communication between the toner accommodation chamber and the toner discharging chamber. The toner cartridge also includes a screw, with at least a part of the screw being positioned in the passage. In a first cross-sectional plane perpendicular to a toner feeding direction of the screw, a minimum cross-sectional area of the passage is Asmin, and in a second cross-sectional plane perpendicular to the toner feeding direction, the toner accommodation chamber has a cross-sectional area Cs that is larger than Asmin.

A toner cartridge includes a pump portion that is variable in volume, a feeding path portion including a connection opening connected to the pump portion at a first end and including a discharge opening at a second end, and a toner accommodating portion connected to an intermediate portion between the first end of the feeding path portion and the second end of the feeding path portion. A volume change amount of the pump portion is greater than a total volume from the connection opening to the discharge opening.

An image forming apparatus includes a developer container to and from which a replenishment container is attachable and detachable and which includes an accommodating portion that accommodates developer and a replenishment port, an agitation member, an opening/closing member configured to be movable between a closed position and an open position, a drive source for driving the agitation member, and a control portion configured to control the drive source. The apparatus is configured such that image formation is not possible when the opening/closing member is at the open position, and the agitation member is capable of driving in a case where the opening/closing member is at the open position.

An image forming apparatus is configured to allow a replenishment container to be detachably attached thereto. The image forming apparatus includes a drum unit including a photosensitive drum, and a development unit. The development unit includes a development roller, a reception portion configured to receive the replenishment container. The development unit is movable relative to the drum unit. The image forming apparatus further includes a housing including an opening/closing member movable between a cover position, at which the opening/closing member covers the reception portion, and an exposing position, at which the reception portion is exposed, and a support member configured to be movable between a support position, at which the support member supports the development unit, and a retracted position, at which the support member is retracted from the support position, in conjunction with the movement of the opening/closing member.

An image forming system includes a toner container and an image forming apparatus to which the toner container is detachably mountable. The image forming apparatus includes a mounting portion to which the toner container is detachably mountable. The toner container includes an accommodating portion configured to accommodate toner, a discharge portion provided with an opening for discharging the toner in the accommodating portion to outside of the toner container, a rotatable member rotatable, relative to the discharge portion, about a rotational axis in a first rotational direction and a second rotational direction that is opposite to the first rotational direction, and a projection provided below the opening of the discharge portion, the projection having inner peripheral surface such that, when the toner container is oriented in a predetermined direction in which the rotational axis extends in a direction of gravity and at least a part of the discharge portion is below the accommodating portion, the inner peripheral surface faces inward in a radial direction of an imaginary circle centered on the rotational axis.

A cartridge includes a casing including a toner storage chamber storing toner and a toner discharge chamber having an outlet, a conveyance member conveying the toner from the toner storage chamber to the toner discharge chamber, an action member attached to the conveyance member and repeating an action of shifting between an entering state of entering the outlet and a retraction state of retracting from the outlet, and a pump expanding and contracting to be shifted between a first state and a second state in which the internal space is smaller in volume than in the first state, the pump putting air into the toner discharge chamber by being shifted from the first state to the second state, thereby discharging the toner from the toner discharge chamber through the outlet, and the pump taking in air by being shifted from the second state to the first state.

An attached portion of an image forming apparatus includes a rotating member of which at least a part is exposed outside the image forming apparatus when the developer container is attached, and a rotation restricting mechanism that is movable between a restricting position to restrict rotation of the rotating member and an allowable position to allow rotation of the rotating member, and includes a restricting member that is at the restricting position when the developer container is not attached. The developer container is attached to the attached portion so that the discharging portion engaging portion and the shutter engaging portions are engaged with the frame engaged portions and the rotating member engaged portions respectively when the container shutter is in the close state, and the restricting member moves from the restricting position to the allowable position when the developer container is attached to the attached portion.

A toner container includes a toner accommodating body and a nozzle including an opening configured to form a part of a discharge passageway through which toner may be discharged to outside of the toner container. A shutter is configured to open and close the opening of the nozzle, with the shutter being rotatable about a rotational axis between a first position in which the shutter closes the opening of the nozzle and a second position in which an opening of the shutter aligns with the opening of the nozzle to form the discharge passageway. A projection is positioned at an end portion of the toner container, with the projection including a first surface, a second surface, and a third surface. When the toner container is oriented such that the toner accommodating body is above the nozzle, the nozzle is above the projection, and the projection is at a bottommost side of the toner container, (i) the opening of the nozzle is positioned such that toner may be discharged from a lateral side of the toner container that is above the bottommost side, (ii) the first surface faces downward, (iii) the second surface faces downward, and (iv) the third surface faces upward.

An image forming apparatus includes a stacking portion which is a part of a top surface of an exterior of the image forming apparatus. The stacking portion is positioned downstream of a discharging outlet in a discharging direction and on which the recording material discharged from the discharging outlet is stacked and includes a first surface on which the recording material discharged from the discharging outlet is stacked, and a second surface which is positioned outward with respect to the discharging outlet in a width direction orthogonal to the discharging direction. A supplying inlet is located below the first surface, wherein a downstream end of the first surface is positioned downstream of a downstream end of the second surface in the discharging direction, and wherein the first surface is rotatable to expose the supplying inlet.