An imaging system includes a transfer belt that is rotatable, a transfer roller that contacts the transfer belt, and a conductive device that contacts a surface of the transfer roller, to supply a bias to the transfer roller. The transfer roller has a hollow portion.

A cylinder member includes: a cylinder body having a cylindrical shape; a sheet member wound on the cylinder body; a first attachment portion provided at one end portion of the sheet member in a circumferential direction, the first attachment portion being detachably attached to the cylinder body; and a second attachment portion provided at the other end portion of the sheet member in the circumferential direction, the second attachment portion being detachably attached to the cylinder body.

An image forming apparatus includes: a transfer cylinder that is supported on an image forming apparatus body and rotates; a rotating member that is coaxial with the transfer cylinder and rotates integrally with the transfer cylinder; a circulating member that is provided with a holding part that holds a front end portion of a recording medium, is suspended around the rotating member, and transports the recording medium by circulating as the rotating member rotates; a transfer unit that is supported on the image forming apparatus body and has a transfer belt that transfers an image on a recording medium transported by the circulating member by sandwiching the recording medium together with the transfer cylinder at a nip position; a first image forming part that is supported on the image forming apparatus body and forms the image on the transfer belt; and a second image forming part that is supported on the image forming apparatus body at a position lower than the first image forming part and forms the image on the transfer belt. Mass of the second image forming part is larger than mass of the first image forming part.

A transfer device includes a plurality of photoconductors, a belt, a plurality of primary transfer rollers and control circuitry. The plurality of primary transfer rollers is disposed for the plurality of photoconductors, respectively. The plurality of primary transfer rollers brings the belt into contact with or separate the belt from the plurality of photoconductors. The control circuitry causes at least one of the plurality of primary transfer rollers to press against a corresponding at least one of the plurality of photoconductors to shift a printing mode.

A transfer unit includes first and second rollers, first and second bearing members, a roller holder, first and second urging members, a switching cam, and a driving mechanism. The switching cam includes first and second guide holes with which first and second engaging portions formed on the first and second bearing members engage. The first and second guide holes are formed, each in an approximately arcuate shape, at positions at different distances from the rotation center of the switching cam. By rotating the roller holder, one of the first and second rollers is arranged opposite an image carrying member and, by rotating the switching cam, the first or second roller arranged opposite the image carrying member is arranged selectively either at a reference position where the first or second roller is in pressed contact with the image carrying member or at a released position.

An image forming apparatus includes: an image carrier body to be transported; an image forming unit that forms an image on the image carrier body; a change roller that is in contact with an inner peripheral surface of the image carrier body so as to be rotatable around a rotation axis and that is capable of changing an angle of the rotation axis with respect to a width direction of the image carrier body; a flywheel provided at the change roller; and a driving mechanism that applies a driving force for changing an angle of the rotation axis with respect to the width direction to an applied portion that moves together with the change roller. A direction of the driving force applied to the applied portion by the driving mechanism is opposite to a direction in which the applied portion moves due to gravity acting on the flywheel.

A transfer belt includes: an elastic layer, wherein the transfer belt is used to transfer a toner image onto a recording medium, the toner image being carried on a first main surface which is one of a pair of main exposed surfaces including the first main surface and a second main surface, when, using a lower block and an upper block, the transfer belt is placed on an upper surface of the lower block, a part of the transfer belt is interposed between a curved convex surface and a curved concave surface, and a pressed region reaches a pressing force of 200 [kPa] and is constantly pressed by the pressing force, if “a” represents a maximum value of displacement of a measurement region, and “b” represents displacement of the measurement region after convergence, E [−] calculated by (a−b)/b satisfies a condition of 0.2≦E≦3.

A sheet supplying apparatus includes an alignment member pivotable to an alignment location for blocking and aligning fore-ends of media contained on a loading table, and a transport-allowing location for allowing a medium picked up by a pickup member to be transported, a cam gear including a gear portion partially including a tooth-omitted portion, and a cam portion for switching the alignment member between the alignment location and the transport-allowing location at first and second rotating locations, a swing arm pivotable about a same axis as a rotation axis of a main gear, and first and second swing gears supported by the swing arm to interlock with the main gear, selectively interlocking with the gear portion according to a rotating direction of the main gear, and rotating the cam gear to the first and second rotating locations.

The image forming apparatus forms a test chart on an image bearing member, the test chart including a plurality of test images including a first test image of a first density and a second test image formed at a position different from a position of the first test image in a conveying direction of a recording medium, the second test image having a second density different from the first density. The image forming apparatus transfers the test chart to the recording medium with a transfer roller and controls the rotation velocity of the transfer roller when the recording medium passes through a transfer portion based on a result of reading the test chart on the recording medium with a reading unit.

The belt conveyance device includes a plurality of rollers, a belt, a meandering correction part, and an adjustment part. The rollers are disposed at intervals each other and rotate around axes. The belt is disposed around the plurality of rollers and travels. The meandering correction part shifts one end portion in an axial direction of a tension roller included in the plurality of rollers in a radial direction within a predetermined range to correct a meandering of the belt. The adjustment part shifts the other end portion in the axial direction of the tension roller in the radial direction such that a position of the one end portion of the tension roller is variable under a state where the meandering of the belt is corrected.