An image forming apparatus includes a casing; a process unit for forming a developer image on a sheet; an image exposing unit; a sheet cassette detachably mounted to the casing; a feeding roller for single the sheet from the cassette; a feeding guide provided in the casing and configured to guide the sheet moving from the cassette to the process unit. The exposing unit is disposed right above the feeding roller. The process unit is at a position the same position as the exposing unit in the vertical direction and downstream of the exposing unit in a horizontal direction. The cassette is below the feeding roller. The guide is between the exposing unit and the cassette in the vertical direction. The guide includes upper and lower guides. When the cassette is drawn out of the casing, the lower guide moves to an accommodating portion in the cassette.

An image forming apparatus includes a unit horizontally insertable and drawable with respect to a main body frame, and a lock mechanism for the unit. The lock mechanism includes a lock member which has an engagement projection engageable with an engaged portion formed in the main body frame, and a biasing member which biases the lock member in a first direction toward engagement of the engagement projection with the engaged portion. Along with insertion of the unit, the lock member moves in a second direction, and when the unit is inserted to a predetermined position, biasing force of the biasing member causes the lock member to move in the first direction and the engagement projection engages with the engaged portion. By moving the lock member in the second direction, engagement between the engagement projection and the engaged portion is released to make it possible to draw the unit.

An image forming apparatus includes a housing and a pair of cassette guides. The housing is provided with a cassette storage space and a unit storage space. The unit storage space is disposed above the cassette storage space and configured to slidably support an image forming unit. The housing has a pair of side plates arranged to be opposite to each other in a direction intersecting a sliding direction of the image forming unit. The pair of cassette guides is provided in the cassette storage space and arranged inside the pair of side plate. A guide rail part is formed by a gap between the side plate and the guide cassette arranged inside the side plate, and a top face of the cassette guide. A unit-side rail provided to the image forming unit is slidably engaged with the guide rail part.

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.

Provided is an opening/closing unit including a cover member and a conveying unit. The cover member is provided to one side surface of an apparatus main body so as to open and close a sheet conveying path. The conveying unit is provided inside of the cover member in the apparatus main body. The sheet conveying path includes a first conveying path formed between the conveying unit and the apparatus main body, and a second conveying path formed between the conveying unit and the cover member. When an operating lever of the cover member is rotated to a second position, opening operation of the cover member is enabled. When the operating lever is rotated to a first position in a state where the cover member is opened, the conveying unit rotates with respect to the cover member so that the second conveying path is opened.

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: a main casing; a drum cartridge; and a developing cartridge. The drum cartridge includes a photosensitive drum having a rotational axis. The drum cartridge is drawable from the main casing in a first direction where the axis of the photosensitive drum extends. The developing cartridge is drawable from the main casing in the first direction. The developing cartridge includes: a developing roller; a front wall; and a first developing-device frame. The front wall is disposed at a downstream end of the developing cartridge in the first direction. The first developing-device frame supports the developing roller. The front wall and the first developing-device frame are overlapped with each other when viewed in the first direction. The first boss goes through the first hole of the front wall.

A process cartridge is detachably mountable to a main assembly of an electrophotographic image forming apparatus. The cartridge includes an electrophotographic photosensitive drum, a developing roller, a drum unit containing the drum, a developing unit containing the roller and being movable so the roller contacts and is spaced from the drum, and a first force receiver receiving a force from a main-assembly first force applier by movement of a door from open to closed positions when mounting the cartridge and a second force receiver movable from a stand-by position by movement of the first force receiver by a force received from the first force applier. The second force receiver takes a projected position receiving a force from the second force applier to move the developing unit so the roller moves out of contact with the drum, the projected position being higher than the stand-by position.

An image forming apparatus includes: a main casing; a drum cartridge; and a developing cartridge. The drum cartridge includes a photosensitive drum having a rotational axis. The drum cartridge is drawable from the main casing in a first direction where the axis of the photosensitive drum extends. The developing cartridge is drawable from the main casing in the first direction. The developing cartridge includes: a developing roller; a front wall; and a first developing-device frame. The front wall is disposed at a downstream end of the developing cartridge in the first direction. The front wall has a first hole. The first developing-device frame supports the developing roller. The first developing-device frame includes a first boss extending in the first direction. The first boss goes through the first hole of the front wall.