An image forming apparatus includes first and second image forming portions and a belt. The first and second image forming portions include first and second image bearing members, and first and second transferring members, respectively. The belt nips and feeds a recording material. The first image forming portion is disposed upstream of the second image forming portion in a moving direction of the recording material, and a plurality of members including the first and second image bearing members are integrally assembled and are mountable on or dismountable from a main assembly of the image forming apparatus. A film thickness of a surface of the first image bearing member is larger than a film thickness of a surface of the second image bearing member, circumferential speed ratios or contact pressures of rotating components differ, and/or mass ratios of components of respective developers differ.

An image forming apparatus includes plural photosensitive members, a scanner unit for scanning the photosensitive members, and a fixing unit for fixing toner images. The scanner unit includes a rotatable polygonal mirror for reflecting laser beams emitted in correspondence to respective photosensitive members, reflecting members for reflecting the laser beams, and a box for accommodating the polygonal mirror and the reflecting members. The box includes plural outlets for the laser beams. Of the reflecting members, first and second reflecting members reflect laser beams toward corresponding first and second outlets respectively positioned farthest from and closest to the fixing unit. A distance between the first outlet and its corresponding photosensitive member is longer than a distance between the second outlet and its corresponding photosensitive member, whereas a distance between the first reflecting member and the polygonal mirror is shorter than a distance between the second reflecting member and the polygonal mirror.

An image forming apparatus includes a cartridge and a main body into which the cartridge is removably installed. The cartridge includes a first unit and a second unit that is movably connected to the first unit. The main body includes a rotating member, a supporting member disposed at a position away from the rotating member, and a swingable member that is pivotally movable about the supporting member and configured to be moved by the rotating member. The swingable member is movable between a first position at which the swingable member is in contact with the second unit and a second position at which the swingable member is retracted from the first position. Installation and removal of the cartridge into and from the main body is enabled in a state where the swingable member is at the first position and is supported by the rotating member.

A controller is configured to control a print engine and a conveyor to form an image on both sides of a sheet. The controller is configured to: in a case where images to be formed on both sides of each of an Nth (N is a positive integer) sheet, an (N+1)th sheet, and an (N+2)th sheet are all monochrome image or all color image, convey the (N+2)th sheet to the print engine and form an image before forming an image on both sides of the (N+1)th sheet; and in a case where the images to be formed on both sides of each of the Nth sheet, the (N+1)th sheet, and the (N+2)th sheet are a mixture of the monochrome image and the color image, convey the (N+2)th sheet to the print engine and form an image after forming an image on both sides of the (N+1)th sheet.

An image forming device is provided with a housing formed with an opening, a cover configured to move between a closing position and an opening position, and a plurality of process cartridges including a first process cartridge and a second process cartridge. The first and second process cartridges respectively include first and second photosensitive drums configured to rotate about first and second drum axes both extending in a first direction. The first and second developing devices are configured to supply toner to the first and second photosensitive drums, respectively. The first and second supplying devices are formed with first and second supply ports through which the toner to be supplied to the first and second developing devices are provided, respectively. Both the first and second supplying ports are opened to outside the housing.

An image forming apparatus includes a first image forming portion, a second image forming portion, a belt, a charging voltage applying portion, and a transfer voltage applying portion. With respect to a movement direction of a recording material, the first image forming portion is provided upstream of the second image forming portion. In an image forming operation, a potential difference between a first transfer voltage and a potential at a first transfer portion, which is formed on a first image bearing member and does not form the image, is greater than a potential difference between a second transfer voltage and a potential at a second transfer portion, which is formed on a second image bearing member and does not form an image.

A glossiness detector includes a glossiness sensor, a glossiness corrector, and a reference plate. The glossiness corrector corrects glossiness detected by the glossiness sensor. The reference plate is used for correction processing of the glossiness sensor. Then, the glossiness corrector acquires a glossy reflection profile of the reference plate that has been detected in advance. The glossiness corrector corrects the glossiness according to the reference plate on the basis of the glossy reflection profile and a gloss distribution of the reference plate that has been detected by the glossiness sensor.

An image forming apparatus includes a plurality of photosensitive members; a scanner unit including light sources, a rotatable polygonal mirror, and reflecting members; and a fixing portion. Parts of the laser beams emitted from the light sources are reflected by the rotatable polygonal mirror toward the fixing device side, and rest parts of the laser beams are reflected by the rotatable polygonal mirror toward a side opposite from the fixing device side. Of the parts of the laser beams reflected by the rotatable polygonal mirror toward the fixing device side, the laser beam reflected toward the reflecting member provided at a position remotest from the rotatable polygonal mirror travels downward relative to a horizontal direction. A rotational axis of the rotatable polygonal mirror is inclined relative to a vertical direction.

An image forming apparatus is described. An image forming apparatus may include an image forming apparatus body and a tandem type photosensitive unit slidable with respect to the body, wherein the unit includes: a frame; a plurality of photosensitive bodies; a plurality of developer cartridges, including developer carriers, detachably mountable on the frame; and a pressing portion provided on the frame for pressing each of the cartridges so that the developer carrier thereof is directed toward the corresponding photosensitive body, each of the cartridges is pivoted to be movable to an imaging position pressed by the pressing portion and a detached position released from the pressing by the pressing portion, and the body is provided with an abutting portion abutting the cartridge located on the detached position thereby pivoting the cartridge and moving the same to the imaging position when the unit is mounted on the body.

An image forming apparatus includes: a medium transport path; a first image transport path that is disposed so as to oppose the medium transport path and along which an image to be formed on the medium is transported; an image forming part that forms the image and is disposed adjacent to the first image transport path; and a second image transport path that is disposed so as to oppose the medium transport path, that is located at a distance from the image forming part, and along which an image to be formed on the medium is transported, the second image transport path, the first image transport path, and the medium transport path, together surrounding the image forming part.