A developing device includes a developer cartridge and a developing unit. The developer cartridge, in some instances, may include a shutter. This shutter may have a wall for closing a developer supply hole, and be movable, with respect to a developer cartridge casing, between an open position where the supply hole is opened by the wall and a closed position where the supply hole is closed by the wall. The shutter may further include a protrusion that is movable with respect to the wall of the shutter between a first position and a second position in an axial direction. The protrusion, in the first position, is engageable with a developing unit and, in the second position, would be disengaged from the developing unit.

A toner cartridge includes a toner supply pipe and a first shutter. The toner supply pipe has a toner supply opening. When the toner cartridge is mounted onto a main unit, the toner supply pipe moves through an insertion opening from an outside position at which the toner supply opening is located outside a developing frame to an inside position at which the toner supply opening is located inside the developing frame. The first shutter is provided at the toner supply pipe. The first shutter moves relative to the toner supply pipe between an open position at which the toner supply opening is opened and a closed position at which the toner supply opening is closed. The first shutter moves relative to the toner supply pipe from the closed position to the open position in a state where the toner supply pipe is located at the inside position.

A developing device for forming an image by developing an electrostatic latent image formed on an image carrier with a developer, includes: a developing container that accommodates the developer, a developing roller that faces the image carrier, is disposed adjacent to the developing container, and conveys the developer accommodated in the developing container to the image carrier, and a developer discharging part that is provided in the developing container and discharges a part of the developer, wherein a discharge amount of the developer discharged by the developer discharging part is controlled on the basis of a charge amount of a toner included in the developer.

A developer supply container includes a developer accommodating chamber capable of accommodating developer, a storage portion provided in the developer accommodating chamber and capable of storing a predetermined amount of the developer to be discharged through a discharge opening, and a pump portion actable on the storage portion. A suppressing portion is provided, with the suppressing portion being capable of suppressing air directed toward the developer accommodating chamber from the pump portion, and with the suppressing portion permitting supply of air from the pump portion to the storage portion in a discharge operation.

A developing device includes a developer cartridge and a developing unit. The developer cartridge, in some instances, may include a shutter. This shutter may have a wall for closing a developer supply hole, and be movable, with respect to a developer cartridge casing, between an open position where the supply hole is opened by the wall and a closed position where the supply hole is closed by the wall. The shutter may further include a protrusion that is movable with respect to the wall of the shutter between a first position and a second position in an axial direction. The protrusion, in the first position, is engageable with a developing unit and, in the second position, would be disengaged from the developing unit.

A toner cartridge includes a toner supply pipe and a first shutter. The toner supply pipe has a toner supply opening. When the toner cartridge is mounted onto a main unit, the toner supply pipe moves through an insertion opening from an outside position at which the toner supply opening is located outside a developing frame to an inside position at which the toner supply opening is located inside the developing frame. The first shutter is provided at the toner supply pipe. The first shutter moves relative to the toner supply pipe between an open position at which the toner supply opening is opened and a closed position at which the toner supply opening is closed. The first shutter moves relative to the toner supply pipe from the closed position to the open position in a state where the toner supply pipe is located at the inside position.

An image forming apparatus includes: an image forming portion that includes a developing portion configured to supply toner to an image bearing member bearing an electrostatic latent image formed thereon to develop the electrostatic latent image as a toner image, and is configured to form a toner image on a long paper sheet; a notification portion configured to notify a user about information; and a control portion configured to calculate, in accordance with coverage of a toner image that is a target of image formation, a toner image formation distance with which successive image formation is possible without forcibly discharging degraded toner from the developing portion, and to control the notification portion to notify the calculated toner image formation distance as a first toner image formation distance.

Provided is a waste toner container including a housing having a first reservoir and a second reservoir, a light sensor including a light emitting portion and a light receiving portion, and a light guide member to connect the light emitting portion with the light receiving portion. The light guide member includes a first detection portion and a second detection portion each including a pair of optical surfaces that are apart from each other, and the first and second detection portions are provided in the first and second reservoirs, respectively.

A developing device includes a developer holder that holds developer, the developer holder being disposed so as to oppose an image holder that holds a latent image and developing the latent image with the developer; a housing that accommodates the developer holder with the developer holder being exposed from an opening portion; a wall section that is provided over an entire region in an axial direction of the developer holder from an edge portion, which is a downstream side in a rotation direction of the developer holder, of the opening portion of the housing, the wall section having an opposing surface that opposes an outer peripheral surface of the image holder to form a gap; and a blocking member that is disposed on one side of the opposing surface in the axial direction and that blocks part of the gap.

A developing unit includes a developing roller, a developing casing to support and allow the developing roller to rotate, the developing casing including a developer supply inlet, a developer discharge outlet, and a developer collection inlet. The developing unit further includes a discharge cover to form a discharge path for a developer discharged from the developer discharge outlet along with the developing casing. The developer collection inlet is positioned in the discharge path to collect a part of the developer moving along the discharge path into the developing casing.