An image forming apparatus includes a toner container, a toner conveyance portion, a container attachment portion, and a biasing mechanism. The toner container has a toner outflow port at a tip portion thereof. The toner conveyance portion is provided in the toner container and conveys toner in the toner container toward the toner outflow port. The container attachment portion supports the toner container. The biasing mechanism applies a biasing force to change the toner container from a horizontal attitude to an inclined attitude in accordance with a toner conveyance operation of the toner conveyance portion. When the toner container is in the inclined attitude, the toner outflow port faces diagonally downward.

A mechanism that enables developer replenishment by a simpler structure and a mechanism that enables more user-friendly developer replenishment are provided. An attachment port to which a developer supply bottle containing a developer stored therein is detachably attachable is disposed in an interior of an image forming apparatus. The developer supply bottle can be attached when the cover is in an open state. According to this image forming apparatus, when the developer supply bottle is attached to the attachment port, the developer inside the developer supply bottle moves into a developer housing chamber by its own weight.

A mechanism that enables developer replenishment by a simpler structure and a mechanism that enables more user-friendly developer replenishment are provided. An attachment port to which a developer supply bottle containing a developer stored therein is detachably attachable is disposed in an interior of an image forming apparatus. The developer supply bottle can be attached when the cover is in an open state. According to this image forming apparatus, when the developer supply bottle is attached to the attachment port, the developer inside the developer supply bottle moves into a developer housing chamber by its own weight.

A toner container includes a toner storage unit, a container base portion including a discharge port provided on an outer surface of the container base portion, the outer surface extending in a first direction, the discharge port communicating with the toner storage unit, and a container shutter configured to be rotatable about a rotation axis extending in a direction along the first direction between a shielding position and an open position. The container base portion includes an engaging portion configured to be engaged with an engaged portion of the image forming apparatus so that rotation of the container base portion with respect to the image forming apparatus about the rotation axis is restricted. At least a part of the engaging portion of the container base portion is exposed from the container shutter in a case where the container shutter is in the shielding position.

An electrostatic charge image developing toner that has a binder resin that contains a crystalline resin and toner particles that contain resin particles, in which a loss coefficient tan δS (30) at 30° C. of the resin particles is 1 or more, and a loss coefficient tan δS (50) at 50° C. of the resin particles is less than 1.

A device to supply printing material to a printing material container of a printing apparatus may includes a chamber to store the printing material, a printing material outlet portion through which the printing material stored in the chamber is to be discharged, a plunger head to move in the chamber to discharge the printing material stored in the chamber through the printing material outlet portion, and a plunger handle disengaged from the plunger head and to engage the plunger head to move the plunger head to discharge the printing material.

A toner cartridge includes a container accommodating toner and including a discharge opening. A pump is configured to alternately generate (i) a first air flow from outside to inside of the toner cartridge and (ii) a second air flow from inside to outside of the toner cartridge, with the pump being configured to supply the toner from the discharge opening to outside of the toner cartridge with the second air flow. The cartridge also includes a rotational force receiving portion configured to receive a rotational force from outside of the toner cartridge, with the rotational force receiving portion being configured to drive the pump with rotation of the rotational force receiving portion.

A developer supply container is detachably mountable to a developer receiving apparatus, the developer receiving apparatus including a developer receiving portion provided with a receiving port for receiving a developer and including a portion-to-be-engaged of displacing integrally with the developer receiving portion. The developer supply container includes a discharging portion provided with a shutter opening for discharging the developer accommodated in the developer accommodating portion, and an engaging portion. The engaging portion engages with the portion-to-be-engaged with a mounting operation of the developer supply container to displace the developer receiving portion so as to bring the receiving opening into fluid communication with the shutter opening. The engaging portion includes a curved portion having an angle relative to a mounting direction of the developer supply container, the angle decreasing with approach toward an upstream side in the mounting direction.

An image forming apparatus includes a developer container to and from which the 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.

According to a first aspect of the present invention, there is provided a toner cartridge detachably mountable to a receiving device, the toner cartridge comprising a container including a accommodating portion for accommodating the toner and a discharge opening for discharging the toner from the accommodating portion into the receiving device; and an open/close member including a closing portion for closing the discharge opening and an engaging portion movable relative to the closing portion, the open/close member being rotatable relative to the container between (a) an opening position for causing the closing portion to open the discharge opening and (b) a closing position for causing the closing portion to close the discharge opening, wherein the engaging portion is movable relative to the closing portion between (c) a engaging position for engagement with the receiving device to receive a force for moving the open/close member from the opening position to the closing position when the toner cartridge is dismounted from the receiving device and (d) a retracted position retracted from the engaging position, and wherein the engaging portion is movable from the retracted position to the engaging position with rotation of the open/close member from the closing position to the opening position.