An image forming apparatus includes a plurality of image forming portions; a rotatable endless belt; a plurality of stretching rollers including an inner roller and a steering roller; an outer roller; a steering mechanism; a position changing mechanism; and a controller. In a case that a changing operation for changing a position of the inner roller is performed by the position changing mechanism during execution of a job for forming the toner images on a plurality of recording materials, the controller controls the steering mechanism so that a tilting operation for tilting the steering roller in a predetermined amount in interrelation with the changing operation is executed.

A belt device includes a belt assembly, a pressing force adjuster, and an optical sensor. The belt assembly includes multiple rollers and a belt stretched by the multiple rollers and is rotatable about a rotation axis of one of the multiple rollers. The pressing force adjuster rotates the belt assembly about the rotation axis and adjusts a contact pressure of the belt pressed against an object. The optical sensor is disposed opposite to the one of the multiple rollers, and a position of the optical sensor relative to the rotation axis is fixed while the belt assembly is rotated by the pressing force adjuster.

An image forming apparatus includes: a first image forming unit that includes a first image holding member and a first developing unit, the first developing unit accommodating a first developer that includes a first toner and a first carrier; a first transfer unit; a second image forming unit that is disposed downstream of the first image forming unit in a traveling direction of a transfer medium and includes a second image holding member and a second developing unit, the second developing unit accommodating a second developer that includes a second toner and a second carrier; and a second transfer unit, in which a volume resistivity of the first carrier is higher than a volume resistivity of the second carrier, and a volume average particle diameter of the first carrier is more than a volume average particle diameter of the second carrier.

An image forming apparatus includes an endless belt, an inner roller, an upstream roller and a pressing member, and a guiding member. In a cross-section perpendicular to a rotational axis of the inner roller, a downstream free end of the guiding member is disposed downstream of a pressing portion normal line Lc with respect to the feeding direction of the sheet, where L is a reference line which is a common tangent of the inner roller and the upstream roller in a contact portion relative to the belt, Ld is a pressing portion tangent line, parallel with the reference line, of the belt in a region where the pressing member contacts the belt, and Lc is the pressing portion normal line passing through a contact point between the belt and the pressing portion tangent line Ld and perpendicular to the reference line L.

First and second abutment portions are disposed in a cleaning container. The first abutment portion is arranged on the outer side relative to a first cleaning member in a width direction of a belt at a position corresponding to the first cleaning member in a circumferential direction of the belt and abuts against the outer peripheral surface of the belt. The second abutment portion is arranged on the outer side relative to a second cleaning member in the width direction at a position corresponding to the second cleaning member in the circumferential direction and abuts against the outer peripheral surface of the belt. The outer end of the first abutment portion is located on the inner side relative to the end of the first roller, and the inner end of the second abutment portion is located on the outer side relative to the end of the second roller.

A roller device includes a first roller; a second roller that rotates around a rotation axis extending in a first direction and that is disposed upstream of the first roller in a second direction; a bearing that supports the second roller and includes a projection; an urging unit that urges the bearing in the second direction; and a passage member having a gap that defines first and second passages that respectively extend in the first and second directions and supporting the bearing. The projection is inserted in the gap. The bearing is movable in the first and second directions. The first and second rollers are apart from each other when the projection is in the first passage. The bearing is moved in the second direction so that the first and second rollers are pressed against each other when the projection is in the second passage.

A photo drum may be to receive a color separation. A controller may be to change a location of the color separation on the photo drum from a first location to a second location when a separation location history for the color separation is outside of a threshold range.

An image forming apparatus includes: a first image forming unit that includes a first image holding member and a first developing unit, the first developing unit accommodating a first developer that includes a first toner and a first carrier; a first transfer unit; a second image forming unit that is disposed downstream of the first image forming unit in a traveling direction of a transfer medium and includes a second image holding member and a second developing unit, the second developing unit accommodating a second developer that includes a second toner and a second carrier; and a second transfer unit, in which a volume resistivity of the first carrier is higher than a volume resistivity of the second carrier, and a volume average particle diameter of the first carrier is more than a volume average particle diameter of the second carrier.

An image forming apparatus includes: a first image forming unit that forms an image by using first toner; a second image forming unit that forms an image by using another kind of toner different from the first toner; a transfer unit that transfers the images formed by the first image forming unit and the second image forming unit onto an intermediate transfer body and then onto a recording medium; and a setting unit that sets an order of the images that are transferred onto the intermediate transfer body so that the image formed from the other kind of toner is transferred onto an independent image formed from the first toner transferred onto the intermediate transfer body in a case where the independent image formed from the first toner is to be formed on the recording medium.

An image forming apparatus includes image forming units, a transfer unit that transfers a superposed toner image including toner images formed by the image forming units onto a sheet, a fixing unit that fixes the superposed toner image onto the sheet, and a controller that performs control such that a toner image is formed while the amount of toner used per unit area by the second image forming unit when forming a line image is smaller than that when forming a solid image. The image forming units include a first image forming unit that forms a toner image that is transferred onto the transfer unit relatively earlier than the other toner images and a second image forming unit that forms a toner image that is transferred onto the transfer unit relatively later than the other toner images, the first and second image forming units using the same color toner.