An image forming apparatus includes a first urging member including a first end portion and a second end portion positioned on an opposite side of the first end portion, the first urging member configured to urge a first pressing member to a first pressing position, and a second urging member including a third end portion and a fourth end portion, the second urging member configured to urge a second pressing member to a second pressing position. The second end portion is arranged more distant from the first pressing member than the first end portion and is arranged between the first pressing member and the second pressing member in an axial direction, and the fourth end portion is arranged more distant from the second pressing member than the third end portion and is arranged between the first pressing member and the second pressing member in the axial direction.

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 imaging system includes: a housing including a developing chamber, a developing roller located in the developing chamber to transport a developer and spaced apart from the housing; a conveyance path extending along at least part of a periphery of the developing roller in order to form a flow of air including the developer; and a control member. The developing roller includes a peeling pole at a fixed position with respect to the housing, to discharge the developer. The control member is located along the conveyance path in proximity to the peeling pole of the developing roller, to reduce a flow rate of the air flowing through the conveyance path.

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.

An image forming apparatus includes: a photosensitive drum; a developing roller; a separation mechanism for moving the developing roller between a contacting position contacting the photosensitive drum and a separated position separated from the photosensitive drum; a first tray; a first sheet feed mechanism for feeding a sheet from the first tray toward the photosensitive drum; a first sheet sensor for detecting passage of the sheet at a prescribed position; and a controller. The controller of the image forming apparatus is configured to perform: when a printing operation is performed onto the sheet ted from the first tray, feeding the sheet in the first tray to the prescribed position and maintain the sheet; moving, on or after the first sheet sensor detects the sheet, the developing roller to the contacting position.

An image forming apparatus includes an image bearing member, a developing member, a controller configured to carry out switching control between a first state in which the developing member is caused to act on the image bearing member and a second state in which the developing member is not caused to act on the image bearing member, a transfer member, and a detector configured to read density information of the recording material. The controller detects a fog density on the basis of a difference in density information between a fog non-occurrence region of a non-image region of the recording material in the second state and a fog occurable region of the non-image region of the recording material in the first state.

An image forming apparatus includes an image bearing member, a developing member, a controller configured to carry out switching control between a first state in which the developing member is caused to act on the image bearing member and a second state in which the developing member is not caused to act on the image bearing member, a transfer member, and a detector configured to read density information of the recording material. The controller detects a fog density on the basis of a difference in density information between a fog non-occurrence region of a non-image region of the recording material in the second state and a fog occurable region of the non-image region of the recording material in the first state.

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 may include a photosensitive member, a developing device including a developing roller, pressing members configured to engage with the developing device and springs configured to urge the pressing members. In some examples, each of the pressing members may be configured to contact and move the developing device between various positions based on the urging of the springs. Additionally or alternatively, various ends of a contact surface of the developing roller configured to contact developer may be disposed relative to an axis line of the developing roller and pressing surfaces of the pressing members.

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.