This invention provides a developing apparatus including: first and second chambers containing developer and configured to form a circulation path of the developer; a first feeding member arranged in the first chamber and feeding the developer in a first direction; a second feeding member arranged in the second chamber and feeding the developer in a second direction opposite to the first direction; first and second communication parts through which the developer is transferred; a feeding path having a discharging port and communicating with the first chamber on a downstream side relative to the first communication part in the first direction to feed the developer toward the discharging port; a sealing part sealing the developer; a feeding path sealing part sealing the feeding path on an upstream side relative to the discharging port in the first direction; and an unsealing mechanism receiving a driving force and unsealing the sealing part.

A toner case includes a case main body, a shutter mount and a shutter. The case main body contains a toner to be replenished to a development device provided in an apparatus main body and is detachably attached to the apparatus main body. The case main body has an opened face on which a discharge port is arranged and the discharge port corresponds to a replenishment port of the development device in a state where the case main body is attached to the apparatus main body. The shutter mount is provided to form a gap between the opened face of the case main body and the shutter mount. The shutter is provided between the opened face of the case main body and the shutter mount to be slidable to open and close the discharge port. The shutter mount includes a film which comes into sliding contact with the shutter.

A toner case includes a case main body, a shutter mount and a shutter. The case main body contains a toner to be replenished to a development device provided in an apparatus main body and is detachably attached to the apparatus main body. The case main body has an opened face on which a discharge port is arranged and the discharge port corresponds to a replenishment port of the development device in a state where the case main body is attached to the apparatus main body. The shutter mount is provided to form a gap between the opened face of the case main body and the shutter mount. The shutter is provided between the opened face of the case main body and the shutter mount to be slidable to open and close the discharge port. The shutter mount includes a film which comes into sliding contact with the shutter.

An image forming apparatus includes: a photosensitive drum; a toner cartridge having a toner supply port; and a developing unit including: a developing roller; a developing frame; and a conveyance portion capable of conveying toner contained in the toner cartridge to the developing frame. The conveyance portion including: a coupling tube capable of being coupled to the toner cartridge and having a toner receiving port that faces the toner supply port in a state where the coupling tube is coupled to the toner cartridge; a conveyance tube fixed to the developing frame, the conveyance tube being movable with respect to the coupling tube, in a state where the coupling tube is coupled to the toner cartridge and the toner receiving port faces the toner supply port; and a shutter movable between an open position and a closed position.

A developer container holder for holding a developer container including a developer supply port and a shutter for opening and closing the developer supply port guides the developer container in a first direction when the developer container is attached to the developer container holder and in a second direction when the developer container is removed from the developer container holder, and includes: a holder that holds the developer container; a support that supports the holder slidably within a region in a direction in which the developer container is attached to and removed from the developer container holder; and an elastic member placed between the holder and the support to urge the holder in the first direction when the holder is on a first side of a position in the region and in the second direction when the holder is on a second side of the position in the region.

A toner cartridge includes a casing, a toner conveyance unit, a cover, and a first protrusion. The casing includes a first toner-accommodating section having a first internal space for accommodating toner. The first toner-accommodating section has a first opening. The toner conveyance unit is rotatable and configured to convey toner from the first internal space to the first opening. The cover covers the first opening and has a second opening for allowing toner to be discharged therethrough. The cover has a circumferential surface at which a plurality of gear teeth is provided. The gear teeth are configured to move a developing shutter provided at a developing unit for opening or closing an opening of the developing unit. The first protrusion is configured to release the developing shutter from a locking member of the developing unit for locking the developing shutter.

An image forming system includes a toner container and an image forming apparatus to which the toner container is mountable. The toner container includes a projection that includes an inner peripheral surface centered on a central axis of the toner container. When the toner container is oriented in a predetermined direction, the projection has a downward guide surface facing downward and an upward guide surface facing upward. When the toner container is moved downward in a direction of the central axis toward a mounting portion of the image forming apparatus, (i) the downward guide surface is configured to guide a guided member of the image forming apparatus so that the guided member is rotated in a rotational direction about the central axis, and (ii) the upward guide surface is configured to guide the guided member so that the guided member is moved up after the guided member is rotated in the rotational direction by the downward guide surface.

A toner container for use with a developer unit of an image forming device according to one example embodiment includes a body having a front that leads during insertion of the toner container into the image forming device and a rear that trails during insertion of the toner container into the image forming device. An outlet port is positioned on a bottom of the body and adjacent to the front of the body for exiting toner from the toner container. An engagement surface is positioned at the bottom of the body and adjacent to the front of the body for contacting and pushing open a developer shutter of an inlet port of the developer unit in a direction of insertion of the toner container into the image forming device during insertion of the toner container into the image forming device.

A shutter mechanism includes a shutter, a shutter support, and an elastic member. The shutter moves in one direction to close an opening. The shutter support supports the shutter. The elastic member biases the shutter and the shutter support in opposite directions. The shutter includes an abutting portion to hook on the shutter support with the abutting portion being biased by the elastic member. At least one of the abutting portion and the shutter support has a hook strengthening structure to strengthen hooking of the shutter on the shutter support.

The present invention provides an image forming apparatus including: a first moving member pressed and moved by an openable/closable member when the openable/closable member is opened, and switching a cartridge from a state where the cartridge is positioned in an image forming position to a state where the positioning is released; and a second moving member pressed and moved by the openable/closable member when the openable/closable member is opened, and moving the exposure member from an exposure position to a retracted position, wherein when the positioning of the cartridge is released, a reaction force applied from the first moving member to the openable/closable member reaches a first peak, when the exposure member is moved to the retracted position, a reaction force applied from the second moving member to the openable/closable member reaches a second peak, and timing of the first peak is different from timing of the second peak.