A developing device includes a developer carrying member for developing an electrostatic image with a developer, a developer container including a developer accommodating portion, a developing opening, and a developing chamber, and a developer supplying member that includes a shaft member, a first feeding member, and a second feeding member. The first feeding member has a length L1 measured in an axial direction of the developer carrying member and has a rotational radius R1 measured from a rotation center of the shaft member, and the second feeding member has a length L2. When a length of the developing opening is L3, a shortest length from the developing opening to the shaft member is L4, and a length from the developer carrying member to the shaft member is L5, the following relationships are satisfied: L1<L3<L2, and L4<R1<L5.

A driving mechanism includes a first gear mechanism, a motion conversion mechanism, an actuator, and a mechanical clutch. The mechanical clutch includes an input gear that includes a plurality of engaging portions engageable with a displaced portion on a first position. The mechanical clutch switches to a connected state and a non-connected state corresponding to whether or not the engaging portions each engage with the displaced portion of the actuator. The connected state is a state where the rotational power of the first gear mechanism is transmitted to the motion conversion mechanism. The non-connected state is a state where the rotational power of the first gear mechanism is not transmitted to the motion conversion mechanism. The plurality of engaging portions are formed on a plurality of positions within a range of a default center angle less than 180 degrees in a circumferential direction of the input gear.

There is provided a developing apparatus including a conveyance member configured to bend in contact with an inner wall of a conveyance chamber and convey developer, a portion configured to bend the conveyance member, and a first releasing portion configured to release the bending of the conveyance member, a deforming portion configured to bend the conveyance member moved and released from the first releasing portion, and a second releasing portion configured to release the bending of the conveyance member on the downstream side of the deforming portion in the rotational direction of the conveyance member.

A toner storage case includes a case main body, a rotary member, a support shaft portion, a bearing portion, and a toner returning portion. The case main body is configured to store toner therein. The rotary member is provided in the case main body and configured to move the toner by being rotated. The support shaft portion rotatably supports the rotary member. The bearing portion includes a bearing hole that rotatably supports the support shaft portion in a state where the support shaft portion is inserted in the bearing hole. The toner returning portion is provided on an outer peripheral surface of the support shaft portion and configured to return the toner that has entered the bearing hole, in an outward direction toward an outside of the bearing hole as the rotary member is rotated.

A magnetic carrier having a ferrite-type core material and a resin coat layer present on the surface of the ferrite-type core material, wherein the ferrite-type core material contains a magnetic ferrite-type core material particle and an amino group-bearing primer compound; the resin coat layer contains a coating resin A that is a polymer of monomer containing a (meth)acrylate ester having an alicyclic hydrocarbon group; the content of the amino group-bearing primer compound in the ferrite-type core material and the content of the resin coat layer in the magnetic carrier are within the prescribed range.

According to an aspect of the invention, a developing device includes a developing container that accommodates a two-component developer, a toner concentration detecting unit that detects a toner concentration of the developer by a detecting unit exposed to an inner wall of the developing container, a transport member that is disposed within the developing container and stirs and transport the developer with a transport blade having a pitch that is equal to or less than a size of the detecting unit of the toner concentration detecting unit, and a plurality of gap holding members that is provided at a position facing the toner concentration detecting unit of the transport member and holds a gap such that a tip thereof is abutted against the inner wall of the developing container.

A powder transport device includes a falling passage unit having an inclined surface that is inclined so as to narrow an interior space, through which powder falls, in a lower region of the interior space; a transport passage unit that is connected to a lower end of the falling passage unit and that has a passage space that extends in a direction in which the powder is transported; a transport member that rotates in the passage space of the transport passage unit to transport the powder in one direction, which is a transporting direction; and an elastic sheet that is disposed to cover a portion of the falling passage unit including the inclined surface, the elastic sheet including an upper end portion that is fixed and a lower end that serves as a free end and faces the transport member. The elastic sheet includes a projection that extends and projects from the lower end at a position near an upstream end of the lower end in the transporting direction in which the powder is transported by the transport member. The inclined surface has a protrusion that protrudes such that an upstream edge portion of the elastic sheet in the transporting direction is maintained separated from the inclined surface. A contact body is disposed in the passage space of the transport passage unit, the contact body repeating a movement of coming into contact with the projection to raise a portion of the elastic sheet and then moving away from the projection.

A cartridge configured to be attachable to an apparatus main body of an image forming apparatus includes a first unit including a photosensitive drum, a second unit attached to the first unit and including a developing roller, and a second frame member including a toner storage portion and including a toner reception port, the toner storage portion including a first end portion and a second end portion in a rotational axis direction of the photosensitive drum, the toner reception port provided in the first end portion, a toner container configured to be attachable to the second unit, the toner container including a toner discharge port configured to discharge the toner to the toner storage portion through the toner reception port, and a memory, the memory provided in an end portion of the cartridge on the same side as the second end portion of the toner storage portion.

A developing cartridge includes: a first gear; a second gear; a gear cover; and a protrusion. The first gear is rotatable about a first axis extending in a predetermined direction. The first gear is movable from a first position to a second position. The second gear is rotatable about a second axis extending in the predetermined direction upon receipt of a drive force from the first gear. The gear cover has an opening and covers at least a portion of the second gear. The protrusion extends in the predetermined direction. The protrusion is movable with the rotation of the second gear while the first gear moves from the first position to the second position. The protrusion is further movable past the opening at least once after the protrusion moves past the opening once, while the protrusion moves with the rotation of the second gear.

A cartridge includes a casing including a toner storage chamber storing toner and a toner discharge chamber having an outlet, a conveyance member conveying the toner from the toner storage chamber to the toner discharge chamber, an action member attached to the conveyance member and repeating an action of shifting between an entering state of entering the outlet and a retraction state of retracting from the outlet, and a pump expanding and contracting to be shifted between a first state and a second state in which the internal space is smaller in volume than in the first state, the pump putting air into the toner discharge chamber by being shifted from the first state to the second state, thereby discharging the toner from the toner discharge chamber through the outlet, and the pump taking in air by being shifted from the second state to the first state.