An image forming apparatus includes an attaching portion including an operation member configured to be movable together with a container shutter, a toner storage portion configured to store toner received from a receiving port, an actuator configured to regulate a movement of the operation member, and a control unit configured to control the actuator. The operation member is configured to open and close the container shutter from an outside in a state in which the toner container is attached to the attaching portion. In a case where a predetermined condition is met, the control unit controls the actuator to release a regulation of the movement of the operation member.

When a remaining toner amount of an accommodating portion corresponding to an output value before first toner supply is a first remaining toner amount, a remaining toner amount of the accommodating portion based on a toner filling amount in the accommodating portion in an unused state and image information of an image printed from a time of the unused state to a predetermined timing is a second remaining toner amount, a condition that the first remaining toner amount is larger than the second remaining toner amount is a first condition, and a condition that the first remaining toner amount is smaller than the second remaining toner amount is a second condition, the controller sets a discrimination threshold so that the toner container used for the first toner supply is easily discriminated as the first toner container in the first condition is than in the second condition.

A cartridge includes a shutter that opens and closes when the cartridge is attached and detached to a developing unit or image forming apparatus. The cartridge includes a casing having a chamber with a first opening at one end portion allowing toner to flow out of the casing. The cartridge includes a cover that covers the first opening, movable with the casing and having a second opening allowing toner to flow out of the cover. The shutter is located at the one end portion and has a protrusion further from the one end portion than the cover. The developing unit supports the protrusion when the cartridge is mounted thereon, and the casing pivots with the cover relative to the developing unit between a first position where the shutter closes the second opening and a second position where a third opening of the shutter overlaps the second opening.

An image formation unit according to an embodiment may include: an image formation part with a developer reception port; a developer cartridge including: a developer storage section with a developer supply port; a shutter movable between an open position and a closed position; a lock engagement member; and an operation part configured to be operated to move the shutter and rotate the lock engagement member. When the shutter moves from the open position to the closed position that closes the developer supply port and the lock engagement member rotates in conjunction with movement of the operation part, the lock engagement member is engaged with the image formation part to separate the developer cartridge from a peripheral portion of the developer reception port.

A toner housing extends in a first direction. The toner housing stores toner. The toner housing includes a reception portion and a discharge port. The reception portion is located at an end surface of the toner housing at one end in the first direction. The reception portion has a reception port for receiving toner into the toner housing. The discharge port is located between the one end of the toner housing and an other end of the toner housing in the first direction. The discharge port is located on a surface crossing the end surface. The discharge port is for discharging toner in the toner housing. A reception shutter is attached to the reception portion. The reception shutter is movable between a reception shutter closed position at which the reception port is closed and a reception shutter open position at which the reception port is open.

An image forming apparatus to which a toner container is detachably mountable includes a mounting portion to which the toner container is detachably mountable and which includes a receiving port for receiving toner supplied from the toner container, a passage for permitting passing of the toner received through the receiving port and provided with a through hole, and a filter portion provided so as to cover the through hole and for permitting passing of air; and an accommodating portion configured to accommodate the toner received through the receiving port. At least a part of the through hole overlaps with the receiving port as viewed in a horizontal direction perpendicular to a direction of gravitation.

A drum frame includes first and second frames supporting a photosensitive drum, and a support frame configured to support a toner cartridge. The support frame is not movable relative to the photosensitive drum. The support frame has a passage opening through which toner from the toner cartridge passes in a state where the toner cartridge is supported by the support frame. A development housing has a reception opening configured to receive toner that has passed through the passage opening. The reception opening is larger than the passage opening. The development housing supports a development roller. The development housing is movable relative to the photosensitive drum. A seal is located around the passage opening and away from the passage opening. The seal is in contact with the support frame and an edge of the reception opening. The seal seals between the support frame and the edge of the reception opening.

An image forming apparatus includes a cover and a toner container. The cover opens and closes a side surface of an apparatus main body. The toner container is detachably attached to an inside of the apparatus main body. The cover is turned between a close position and an open position where an angle between the side surface of the apparatus main body and the cover is acute. The toner container includes a replenishment vessel and a recovery vessel, and the replenishment vessel and the recovery vessel are arranged in an upper-and-lower direction. The toner container is turned between an attachment position and a detachment position inclined so as to be along the cover. The toner container arranged in the detachment position is detached along the cover arranged at the close position.

A toner housing includes a reception portion and a discharge port. A reception shutter is attached to the reception portion. The reception shutter is movable between a reception shutter closed position at which a reception port is closed and a reception shutter open position at which the reception port is open. The reception portion is connectable to a toner container configured to store toner that is supplied to the toner housing. The reception port is configured to receive toner from the toner container in a state where the toner container is connected to the reception portion and the reception shutter is located at the reception shutter open position. The reception shutter is rotatable, together with the toner container, between the reception shutter closed position and the reception shutter open position in a state where the toner container is connected to the reception portion.

An image forming apparatus includes (i) a development unit including a development frame including a development opening, a toner regulating portion configured to move to a cover position where the toner regulating portion covers the development opening and a retraction position where the toner regulating portion is retracted from the cover position, (ii) a rotary supporting the development unit, and (iii) a toner cartridge attachable to and detachable from the rotary and including a toner frame including a discharge port. In a case where the rotary is in a first posture, the development opening is in a position above the discharge port, and the toner regulating portion is in the cover position. In a case where the rotary is in a second posture, the development opening is in a position below the discharge port, and the toner regulating portion is in the retraction position.