A developing device is detachably supported by an image forming apparatus. The developing device includes a housing that can store developer inside the housing, at least one rotating member rotatably provided for the housing, a first support shaft composed of a conductive member and disposed at an axial end of the rotating member, and a support member including a first bearing portion that supports the first support shaft and constituting a side face of the housing in an axial direction of the rotating member. The first bearing portion includes a first guide portion. The first guide portion protrudes outward from an outer surface of the support member and configured to be guided to an installation position of the developing device during installation of the developing device in the image forming apparatus.

The developing cartridge includes a casing, a developing roller, and a first inclined surface. The first inclined surface is positioned at an outer surface of one end portion of the casing in the second direction. The first inclined surface is fixed to the casing and is inclined relative to the first direction. The first inclined surface is movable in the first direction relative to the photosensitive drum between a first position and a second position together with the casing and the developing roller in a state where the developing cartridge 1 is attached to a drum cartridge. In a state where the first inclined surface is at the first position, the developing roller is in contact with the photosensitive drum. In a state where the first inclined surface is at the second position, the developing roller is in separation from the photosensitive drum.

In a developing unit, one of a frame body and an end portion member, which sandwich a bearing member rotatably supporting a developing roller in an axis direction of the developing roller, includes a hole portion depressed in the axis direction on s surface facing the bearing member, the other of the frame body and the end portion member includes a protruding portion inserted into the hole portion, the protruding portion includes a first region that is press-fitted into an inner wall surface of the hole portion, and a second region that faces the inner wall surface with a gap therebetween, and at least the gap is filled with an adhesive via a communication hole that extends in a direction intersecting the rotation axis direction such that the gap leads to an outside of the frame body.

An image forming apparatus including a main body casing, a drum cartridge and a developing cartridge. The main body casing has an opening and a slot extending in from the opening toward an inside of the main body casing along a first direction. The drum cartridge and the developing cartridge are arranged in a second direction intersecting the first direction in a state where the drum cartridge and the developing cartridge are attached to the slot. The main body casing includes a drum guide groove configured to guide movement of the drum cartridge. The drum cartridge includes a drum protrusion configured to be engaged with the drum guide groove. A width of the drum guide groove in the second direction is decreased toward the inside of the main body casing from the opening.

A developing device includes a developing container having a first stirring chamber and a second stirring chamber that are arranged in juxtaposition with each other and a developer carrier that carries toner in the second stirring chamber. The developing container includes a duct, an air suction port, a first filter, and a second filter. The duct is arranged adjacently to the second stirring chamber and allows air in the second stirring chamber to flow out to an exterior. The air suction port is open along a longitudinal direction of the second stirring chamber and allows communication between inside the second stirring chamber and inside the duct. The first filter covers the air suction port. The second filter is arranged on a downstream side of the first filter in an air circulation direction in the duct and covers an air circulation path in the duct.

A resin molded product whose main component consists of an ethylene-vinyl acetate copolymer resin and carbon black. The ethylene-vinyl acetate copolymer resin has an MFR of 0.5 g/10 min or more and 20 g/10 min or less. The carbon black has an average primary particle diameter of 55 nm or more and 100 nm or less and a DBP oil absorption amount of 100 mL/100 g or more and 300 mL/100 g or less. The content of vinyl acetate is 2.9 parts by mass or more and 12.3 parts by mass or less based on 100 parts by mass of the main component. The resin molded product has a surface resistivity of 720 Ω/□ or less.

An image forming apparatus includes: a main casing; a toner cartridge including a toner casing having a toner outlet for discharging toner in the toner cartridge and a toner shutter for opening and closing the toner outlet; a drum cartridge including a photosensitive drum and a developing unit including a developing casing having a toner inlet for receiving the toner from the toner cartridge, a developing shutter for opening and closing the toner inlet, and a cushion member positioned between the developing casing and the developing shutter. When the developing casing is moved relative to the photosensitive drum while the drum cartridge and the toner cartridge are attached to the main casing, the developing shutter opens the toner inlet, and the toner shutter opens the toner outlet, the cushion member allows movement of the developing casing relative to the developing shutter while the developing shutter engages with the toner cartridge.

A developing cartridge includes: a casing; a developing roller; a shaft extending in a first direction; a first inclined surface; a second inclined surface; an elastic member; and a first protrusion. The shaft is movable in the first direction relative to the casing and the developing roller, and is movable in the second direction together with the same. The first inclined surface is positioned at one end portion of the shaft, while the second inclined surface is positioned at another end portion of the shaft. The first and second inclined surfaces are inclined relative to the first direction. The first protrusion is movable in the first direction together with the second inclined surface. The shaft is movable from a first position to a second position when the second inclined surface receives a pressing force directed in a direction from the another end portion to the one end portion.

An image forming apparatus includes a developer container to and from which a replenishment container is attachable and detachable, the developer container including an accommodating portion, and a supporting portion, wherein the developer container includes a projection portion that is provided at one end portion thereof in the rotation axis direction of the developer bearing member and projects toward the supporting portion more than a center portion of the developer container in a crossing direction crossing the rotation axis direction, the projection portion communicates with the accommodating portion and includes, at a distal end portion thereof, an attachment portion configured such that the replenishment container is attachable thereto in a state of being exposed to the outside of the apparatus, and a replenishment port for replenishing the accommodating portion with developer from the replenishment container is defined in the attachment portion.

A toner including a non-crystalline polyester resin, a crystalline polyester resin, a hydrocarbon wax, and an aromatic petroleum resin is provided. A mass ratio of the aromatic petroleum resin to the hydrocarbon wax is 1.0 or more. The non-crystalline polyester resin contains diol components, and the diol components include an alkylene oxide adduct of bisphenol A and ethylene glycol.