A developer conveying mechanism includes a pipe-shaped conveying path that conveys developer and includes a discharge port formed in part of a side surface thereof, a shutter that is slidably attached to the pipe-shaped conveying path and that is selectively arranged at a closing position overlapping with the discharge port and an opening position retreated from the discharge port, a seal member that is fixed to a seal affixing surface of the shutter, and a biasing member that biases the shutter toward the closing position. The shutter includes the seal affixing surface, which is a flat surface, and a pair of engagement portions that are opposite to each other across the seal affixing surface in a circumferential direction of the pipe-shaped conveying path. The pipe-shaped conveying path includes a pair of guide ribs with which the pair of engagement portions slidably engage.

A toner container information acquiring method includes: measuring a toner amount contained in a resin forming a toner container; and acquiring information regarding mechanical strength of the toner container based on the measured toner amount.

A developing device includes a container having an opening, a developer roller disposed within the container to supply toner to a photosensitive body through the opening, and an air flow passage. The air flow passage receives air from inside of the container and supplies the air, via an end of the container in a longitudinal direction of the developer roller, to an upstream side, in a rotation direction of the developer roller, of a closest position between the developer roller and the photosensitive body. The air flow passage has an outlet that is aligned with a central area in the longitudinal direction of the developer roller.

Provided is an image forming apparatus including an image carrier, an exposure device, a developing device that supplies a developer to form a toner image, and a hardware processor that controls the image carrier, the exposure device, and the developing device. The image forming apparatus further includes a fume prevention plate that covers a part of an internal space of the developing device where the developing roller is disposed and the developer is stored and that prevents the developer from scattering outside from the internal space, a suction duct, and an air suction device. One end of the suction duct is connected to the internal space and another end of the suction duct is connected to the air suction device. The fume prevention plate includes a movable portion. A position of the movable portion can be changed between a first position and a second position different from the first position.

A filter includes a sticker and a filter body. The filter body has a smaller weight density per unit volume at a first side than at a second side opposite the first side. The sticker is disposed around a surface of the second side of the filter body.

When, in a state where a developer borne by a developer bearing member is sandwiched by an opposing portion of an image bearing member and the developer bearing member, C denotes capacitance between the image bearing member and the developer bearing member, ΔV denotes a development contrast, Q/S denotes a charge amount per unit area of the developer borne by the developer bearing member, and Δv denotes a peripheral velocity ratio which is a ratio of a peripheral velocity of the developer bearing member to a peripheral velocity of the image bearing member, a first peripheral velocity ratio is set so that |Q/S×Δv|≤|C×ΔV| is satisfied, and a second peripheral velocity ratio which is larger than the first peripheral velocity ratio is set so that |Q/S×Δv|>|C×ΔV| is satisfied.

A developing device includes: a housing which includes an opening portion open downward and in which a developer is stored in an internal storage space, the storage space being formed of a region of the internal space in which the developer is present; a sealing part that seals the opening portion and is removed to allow the developer to fall through the opening portion; a storage part that stores the developer having fallen through the opening portion; an inlet that is provided in the housing, allows the developer floating from the storage part to flow into the storage space from which the developer has fallen, and is different from the opening portion; and a collecting part that is provided on the housing and collects the developer having flowed into the storage space through the inlet.

A developing device includes a detachably mounted developer supply container configured to supply a developer with compressed air. A developer storage container includes a first opening portion through which the developer is supplied from the developer supply container to the developer storage container with the compressed air, a filter provided on a wall constituting the developer storage container to permit passage of air and restrict passage of the developer, and a stirring member to stir the developer. The developer storage container further includes a second opening portion through which the developer is supplied to a developing portion provided with a developing member. The filter is disposed between the first opening portion and the second opening portion in a rotational axis direction of the stirring member and disposed closer to the second opening portion.

An imaging system includes a rotatable image carrier; a rotatable developer carrier, a storage container, and an air flow generator. The developer carrier transfers toner to the image carrier at a developing region located between the image carrier and the developer carrier. The storage container stores the developer carrier. The air flow generator is separated from the storage container by a gap, and rotates in a rotational direction that is opposite to a rotational direction of the developer carrier, to channel an air flow through the gap when the air flow generator rotates.

A cartridge detachably mountable to a main assembly of an image forming apparatus includes a photosensitive member unit including a photosensitive drum; a sheet configured to remove a deposited matter from a surface of the drum, the sheet being in contact with the surface of the drum at an end portion of the drum with respect to a rotational axis direction of the member; and a developing unit detachably mounted to the member unit, the developing unit including a developing roller configured to supply toner to the drum, and a storage portion configured to store the deposited matter removed from the surface of the drum by the sheet.