An image forming apparatus includes a formation target that is wound around rotating bodies including a driving roller and transported by the rotating bodies including the driving roller while forming a shape having linear portions each of which forms a different angle, which is an acute angle or an angle of zero degrees, with a horizontal direction when viewed in an axial direction of the driving roller, first image forming bodies that are arranged along one of the linear portions in such a manner as to be spaced apart from each other by a first distance and that form images onto the formation target, and second image forming bodies that are arranged along another one of the linear portions, the other linear portion forming the angle larger than the angle formed by the one linear portion, in such a manner as to be spaced apart from each other by a second distance shorter than the first distance and that form images onto the formation target.

An imaging system includes an endless belt, a tensioning system that applies tension to the endless belt, a contact member that engages with the endless belt, and a detector that detects slack at a part of the endless belt. A controller causes the contact member to be separated from the endless belt so that the tensioning system reduces the slack of the endless belt in response to the detector detecting the slack.

An imaging system includes an endless belt, a tensioning system that applies tension to the endless belt, a contact member that engages with the endless belt, and a detector that detects slack at a part of the endless belt. A controller causes the contact member to be separated from the endless belt so that the tensioning system reduces the slack of the endless belt in response to the detector detecting the slack.

An endless belt includes a base material layer containing a polymer material and conductive particles, wherein, in an image obtained by observing a cross section taken along a thickness direction of the base material layer with an atomic force microscope, a proportion of a total area Ap of cross sections of all the conductive particles is 9.0% or more and 14.5% or less with respect to a total cross-sectional area At of the base material layer, and a proportion of a total area Ab of cross sections of conductive particles having an area of 0.01 .Math.m.sup.2 or more among cross sections of the conductive particles is 28.0% or more and 65.0% or less with respect to the total area Ap of cross sections of all the conductive particles.

An image forming apparatus includes an main body, a processing unit, and a pressing member. The main body includes a transfer belt wound around a plurality of rollers. The processing unit can be inserted into and removed from the main body. The processing unit includes a drum that faces the transfer belt in a state of being inserted into the main body. The processing unit forms an image on the surface of the drum. The pressing member is provided on the main body and includes a contacted portion and a contacting portion. The contacted portion comes into contact with the processing unit when the processing unit is inserted into and removed from the main body. The contacting portion comes contact with the transfer belt due to contact with the processing unit to push the transfer belt in a direction away from the processing unit.

An image forming apparatus includes a formation target that is wound around rotating bodies including a driving roller and transported by the rotating bodies including the driving roller while forming a shape having linear portions each of which forms a different angle, which is an acute angle or an angle of zero degrees, with a horizontal direction when viewed in an axial direction of the driving roller, first image forming bodies that are arranged along one of the linear portions in such a manner as to be spaced apart from each other by a first distance and that form images onto the formation target, and second image forming bodies that are arranged along another one of the linear portions, the other linear portion forming the angle larger than the angle formed by the one linear portion, in such a manner as to be spaced apart from each other by a second distance shorter than the first distance and that form images onto the formation target.

An image forming apparatus includes: a belt unit including a transfer belt and a first memory that stores a first sheet conveying speed of the transfer belt; a second memory storing a first reference value and a second sheet conveying speed of the fixing unit a controller configured to: control at least one of the belt motor and the fixing motor to bring the speed difference between the sheet conveying speed of the transfer belt and the sheet conveying speed of the fixing unit closer to the first reference value by setting a rotational speed of the fixing motor based on the first reference value and a first speed difference between the first sheet conveying speed read from the first memory and the second sheet conveying speed read from the second memory.

A belt driving device to drive an endless belt, includes a drive roller and a suspension roller which extend in a first direction and face each other in a second direction. The belt driving device includes a steering roller located between the drive roller and the suspension roller in a tiltable manner. A pulley (or wheel) is located at an end portion of the steering roller. The belt driving device includes a link mechanism which presses the end portion of the steering roller to tilt the steering roller with the movement of the pulley (or wheel).

A drive force transmission mechanism includes a drive pulley, a driven pulley and an endless belt. The endless belt is wound around the drive pulley and the driven pulley and transmits a rotation of the drive pulley to the driven pulley. At least one of the drive pulley and the driven pulley has a protruding part protruding outwardly in a radial direction around an outer circumferential face of the drive pulley or the driven pulley. The belt is a nonmagnetic metal belt having an outer circumferential face and an inner circumferential face. The outer circumferential face has a surface roughness smaller than a surface roughness of the inner circumferential face.

An endless belt includes a base material layer containing a polymer material and conductive particles, wherein, in an image obtained by observing a cross section taken along a thickness direction of the base material layer with an atomic force microscope, a proportion of a total area Ap of cross sections of all the conductive particles is 9.0% or more and 14.5% or less with respect to a total cross-sectional area At of the base material layer, and a proportion of a total area Ab of cross sections of conductive particles having an area of 0.01 μm.sup.2 or more among cross sections of the conductive particles is 28.0% or more and 65.0% or less with respect to the total area Ap of cross sections of all the conductive particles.