A developing apparatus for use in an image forming apparatus includes a developing frame, a rotatable developing member, a regulation blade to regulate developer borne on a developing member surface, and a seal member to prevent developer from leaking outside the developing frame. The regulation blade includes a support plate, a plate-shaped member, and a regulation member. The seal member is fixed to a facing surface of the plate-shaped member, is arranged at a plate-shaped member end portion, is arranged side by side with the regulation member in a rotational axis direction, contacts an end surface of the regulation member, and is disposed between the plate-shaped member and the developing member in a direction intersecting with the rotational axis direction. The plate-shaped member is welded to a region of the support plate excluding a region outside the end surface of the regulation member in the rotational axis direction.

The developing device includes a developing roller, a developer conveying unit, a developer discharge unit, and an air discharge port. The developer conveying unit includes a developing chamber provided with the developing roller and extending in a longitudinal direction of the developing roller, a stirring chamber arranged in parallel to the developing chamber, and a barrier wall having a first communication port and a second communication port, at respective ends in the longitudinal direction, to connect the developing chamber with the stirring chamber. The developer discharge unit extends from the developer conveying unit in the longitudinal direction of the developing roller and includes a developer discharge port to discharge excess developer. The air discharge port is to house a filter to filter a developer, the air discharge port being provided between the developer conveying unit and the developer discharge unit to discharge air in the developer conveying unit.

A developing device includes a developer roller to rotate in a rotation direction, a photosensitive body adjacent the developer roller, and an air flow passage extending through a non-image forming region at a longitudinal end of the developer roller. A closest position is defined where the developer roller and a photosensitive body are closest to one another. The air flow passage extends from inside the developing device and forms an air flow directed toward an upstream side of the closest position, relative to the rotation direction of the developer roller.

An image forming apparatus at least includes: an image bearing member; a developer container; a developer carrying member; and a controller that controls a power source that applies a voltage to the developer carrying member, wherein the developer carrying member has at least a base and a surface layer, the surface layer has an electron donating portion that mainly donates charge to the developer when the developer and the surface layer makes frictional contact to exchange charge and an electron accepting portion that mainly accepts charge from the developer, and the controller applies an AC voltage to the developer carrying member during a period in which an image forming operation is not performed and the developer carrying member is driven, the AC voltage being different from that applied during an image forming period.

A developing device includes a developing member to carry developer stored by a developing frame, and a regulating blade having a support plate fixed to the developing frame, a plate-like member, and a regulating member. One end portion of the plate-like member is opposed to the developing member, and the other end portion is welded to the support plate. The regulating member is fixed to a plate-like member surface, and contacts the developing member to regulate a developer thickness on a developing surface. The regulating member is provided with a recessed portion recessed at a regulating member end portion. The regulating member end portion is lower than a regulating member central portion. A plate-like member region welded to the support plate is located at the plate-like member other end portion and overlaps the regulating member central portion and the regulating member end portion at which the recessed portion is provided.

A developing device includes a first housing member, and a second housing member that is configured by combining a housing, in which a developer accommodation space accommodating a developer and a roll accommodation space accommodating a development roll are provided, and the first housing member with each other and that includes an integrated member obtained by integrally forming a frame-shaped seal attachment portion and an outer shell portion with each other, the seal attachment portion being a portion to which a seal member separating the developer accommodation space and the roll accommodation space from each other is attached, the outer shell portion constituting an outer shell that separates an inside and an outside of the housing from each other.

Disclosed is a development cartridge detachable from a main body of an image forming apparatus. The development cartridge includes a lateral waste toner sealing member contacting an end portion of a photosensitive drum in a lengthwise direction of the photosensitive drum to prevent a waste toner from leaking through the end portion of the photosensitive drum, and a photosensitive frame including a waste toner container to contain the waste toner, a first attachment surface, to which the lateral waste toner sealing member is attached, and a side wall to form a boundary at an upstream side of the first attachment surface with respect to a rotation direction of the photosensitive drum. The lateral waste toner sealing member includes an opposite surface facing the side wall, and a protrusion protruding towards the side wall is provided on the opposite surface.

A seal member includes a seal surface that comes into contact with and slides with an end portion of an outer circumferential surface of a developing roller. The seal surface includes a first seal region configured of a plurality of first fiber bundles including a first fiber having a charge property that repels a developer, and a second seal region configured of a plurality of second fiber bundles including a second fiber having a charge property that attracts the developer, both extending in an inclined direction such that a portion thereof closer to an opening portion of a frame body of a developing unit is located further downstream in a rotating direction of the developing roller, and being alternately disposed in the rotating direction, and a proportion of a portion occupied by the second fiber bundles on the seal surface is at least 5% and not more than 60%.

A developing device includes: a case in which a hollow transporting path is formed; a transporting member configured to transport a developer in the transporting path; a support portion fixed to an end portion of the case by a fastening member to support the transporting member at an end portion of the transporting path; and a cooling unit fixed by being sandwiched between the support portion and the case.

A developing device includes: a storage part in which a developer is stored; a transport body that includes a spiral blade and transports the developer via a rotation thereof; a developing body to which the developer is supplied from the transport body; an attachment part which is disposed between the transport body and the developing body and includes an opening allowing the developer supplied from the transport body to the developing body to pass and to which a sealing member sealing the opening is detachably attached; and a connection portion which extends to cross the opening at a spiral angle of the blade as viewed from the developing body toward the transport body and of which one end portion and the other end portion are connected to the attachment part.