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.

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 photosensitive drum is rotatably supported in a main body. A developing cartridge is detachably mountable on the main body in a state where the photosensitive drum is supported in the main body. The developing cartridge includes a developing device and a frame. The developing device includes a developing roller disposed in confrontation with the photosensitive drum to supply developer to the photosensitive drum when the developing cartridge is mounted in the main body, and a developer-accommodating portion configured to accommodate developer. The frame includes a waste-developer-accommodating portion configured to accommodate waste developer and supports the developing device that is movable relative to the frame. The frame is disposed on an opposite side of the developing roller from the photosensitive drum. An urging member is disposed between the frame and the developing device to urge the developing roller toward the photosensitive drum.

An image forming apparatus includes an image carrier, a toner supply unit, an application roller adjacent to the image carrier, a toner measuring unit, and a control unit. The toner supply unit supplies toner to the image carrier. The application roller applies a lubricant to the image carrier. The toner measuring unit measures an amount of toner transferred from the image carrier to the application roller. The control unit adjusts the supply of toner to be supplied to the image carrier in accordance with the amount of toner measured by the toner measuring unit.

An imaging system includes a developing chamber, a first conveyance path, a second conveyance path, a first air passage and a second air passage. A developing roller located in the developing chamber carries a developer to a developing region where the developing roller is closest to an image carrier. A first stirring-conveying portion is located in the first conveyance path adjacent the developing roller to supply the developer to the developing roller. A second stirring-conveying portion is located in the second conveyance path adjacent the first conveyance path to circulate the developer between the second conveyance path and the first conveyance path. The first air passage has an inlet coupled to the developing chamber and an outlet coupled to the second conveyance path, and the second air passage has an inlet coupled to the second conveyance path and an outlet coupled to the developing chamber.

An image forming apparatus capable of forming images in mono-color and a plurality of colors includes first and second image forming units and a control unit. The image forming unit includes a rotatable image bearing member, a rotatable developing member that contacts the image bearing member to supply a developer to the surface thereof, and a developer supply member that supplies the developer to the developing member. The control unit switches between an image forming operation of forming an image on the image bearing member surface and a cleaning operation of removing an attached matter on the image bearing member surface with the developing member by controlling a voltage applied to the developing member and a voltage applied to the developer supply member.

An image forming apparatus includes a photosensitive member, a charging member, an exposure unit, a developing unit including a developing member, a motor, a contact and separation unit, a controller, an acquiring portion for acquiring information on a switching time which is a time required for switching a state of the developing member from a separated state to a contact state by executing a contact operation by the contact and separation unit, and a setting portion for setting, on the basis of the information on the switching time acquired by the acquiring portion, a start timing which is a timing when the contact operation by the contact and separation unit is started in a preparation operation and which is a timing before a region on the photosensitive member exposed to light in a light emission period reaches a developing position.

A process cartridge includes an image bearer, a developer bearer, and a positioning member. The image bearer is rotatable. The developer bearer is rotatable and opposite to the image bearer. The positioning member determines an opposing distance between the image bearer and the developer bearer, and includes a fitting portion and a groove. A fitted portion of the image bearer rotatably fits to the fitting portion. The groove extends from a ceiling portion to a bottom portion. A shaft portion of the developer bearer is slidingly movable in the groove. The groove is formed such that the shaft portion of the developer bearer contacts the bottom portion and is supported by the bottom portion. The ceiling portion of the groove is open upward so that the shaft portion of the developer bearer is insertable to and removable from the groove.

A photosensitive drum is rotatably supported in a main body. A developing cartridge is detachably mountable on the main body in a state where the photosensitive drum is supported in the main body. The developing cartridge includes a developing device and a frame. The developing device includes a developing roller disposed in confrontation with the photosensitive drum to supply developer to the photosensitive drum when the developing cartridge is mounted in the main body, and a developer-accommodating portion configured to accommodate developer. The frame includes a waste-developer-accommodating portion configured to accommodate waste developer and supports the developing device that is movable relative to the frame. The frame is disposed on an opposite side of the developing roller from the photosensitive drum. An urging member is disposed between the frame and the developing device to urge the developing roller toward the photosensitive drum.

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.