A control member 76 for controlling transmission and blocking of a rotational force by a clutch is rotatably supported by a supporting member which supports a developing frame. a locking portion provided on the control member 76 rotates between a position retracted from a locked portion of the clutch and a position for engaging with the locked portion.

When a position of a developing unit with respect to a photoreceptor unit, the developing unit being mounted in an image forming apparatus, is switched to a contact position from a separation position with a switching unit, the developing unit at the contact position is brought to a state forming a predetermined space with the guide unit through which an airflow generated by a fan and that flows in a longitudinal direction of the guide unit flows, and when the position of the developing unit with respect to the photoreceptor unit, the developing unit being mounted in the image forming apparatus, is switched to the separation position from the contact position with the switching unit, the developing unit at the separation position is brought to a state in which the developing unit enters at least a portion of an area of the predetermined space.

A damper mechanism has first and second rail members, a biasing member, and a slide member. The first rail member is fixed inside the opening/closing member along the up/down direction, and has an oblong guide hole formed therein extending along the longitudinal direction. The second rail member has fixed to a top end part thereof an engaging pin inserted through the guide hole, and has a bottom end part swingably supported on the apparatus main body. The biasing member biases the first and second rail members in a direction in which these approach each other. The slide member is made of resin fixed to the engaging pin, slides while in contact with the first rail member and the opening/closing member, and prevents contact between the engaging pin and an inner circumferential rim of the guide hole.

An example image forming apparatus includes a main body, a driving motor rotatable in a first direction to provide a driving force to a developing cartridge and rotatable in a second direction opposite to the first direction, and a support assembly to, based on the developing cartridge being mounted to the main body, provide the driving force of the driving motor in the first direction to the mounted developing cartridge, and detach the mounted developing cartridge from the main body using the driving force of the driving motor in the second direction.

A drum unit, to which a developer cartridge with a developer roller and a protrusion protruding in an axial direction of the developer roller is attachable, is provided. The drum unit includes a casing, a photosensitive drum to contact the developer roller, a first guide arranged to confront the protrusion along a direction orthogonal to the axial direction when the developer cartridge is attached to the casing to guide the protrusion, a second guide movable between a first position and a second position to guide the protrusion and arranged to confront the protrusion along the orthogonal direction when the developer cartridge is attached to the casing, and an urging member to urge the second guide in a direction from the first position toward the second position. The second guide includes a contact part to contact the first guide when the second guide is in the second position.

An image forming apparatus, including a photosensitive drum, a developer cartridge with a developer roller and a protrusion, a casing, a separator member to move the developer cartridge between a contact position and a separate position, and a first guide to guide the protrusion, is provided. The first guide confronts the protrusion along a direction orthogonal to an axial direction of the developer roller when the developer cartridge is in the contact position. The first guide includes a first guiding surface and a first inclined surface. The first guiding surface extends in parallel with a line connecting a center of a rotation axis of the developer roller with a center of a rotation axis of the photosensitive drum. The first inclined surface inclines with respect to the first guiding surface. The protrusion contacts the first inclined surface when the separator member moves the developer cartridge toward the separate position.

An image-forming apparatus includes: a casing; a first sheet tray provided in a bottom portion of the casing; an image-forming unit configured to form an image on a sheet supplied from a sheet accommodation portion of the first sheet tray; a sheet supplying path; a first conveying path; and a shutter. The sheet supplying path is configured to provide communication between the sheet accommodation portion and the image-forming unit. The first conveying path is provided in one of the casing and the first sheet tray, and has one end formed with an opening and another end configured to communicate with the sheet supplying path, the opening being open downward. The shutter is movable between a closing position closing the first conveying path and an opening position opening the first conveying path.

An image forming apparatus includes an apparatus main body and a unit. The apparatus main body includes a positioning hole extending in a first direction intersecting with a mounting direction of the unit, and a pair of first inner edges extending in the first direction. The unit includes a sheet metal member and a positioning unit formed on a distal end side of the sheet metal member in the mounting direction. The sheet metal member includes a first surface extending along the mounting direction and a second surface located on an opposite side from the first surface. The positioning unit includes a projection piece inserted into the positioning hole, and a protrusion. The protrusion is formed by deforming the sheet metal member such that the second surface of the projection piece is partially perpendicular to the mounting direction and projects to a second direction perpendicular to the first direction.

An image forming apparatus includes a body, a photoreceptor unit, and a developing unit. The developing unit includes a first attaching/detaching lever that moves a developing sleeve from a first position to a second position by lifting the first attaching/detaching lever. The photoreceptor unit includes a second attaching/detaching lever that moves the developing sleeve from the first position to the second position by lifting the second attaching/detaching lever. The photoreceptor unit and the developing unit move the developing sleeve to the second position by lifting the first or second attaching/detaching lever so that the photoreceptor unit and the developing unit are individually detached from the body.

A transfer device includes a transport belt that contacts with a photoreceptor, and transports a recording medium; a transfer roll that transfers the toner image formed on a surface of the photoreceptor to the recording medium while pressing the recording medium to the photoreceptor through the transport belt; an adjusting unit that adjusts a pressing force of the transfer roll against the recording medium; and a controller that controls the adjusting unit so that a first pressing force is stronger than a second pressing force. The first pressing force is the pressing force after the recording medium starts to pass through a transfer position of the transfer roll and is moved by a predetermined distance. The second pressing force is the pressing force when the recording medium starts to pass through the transfer position.