A belt driving device includes an adjustment roller to stretch and rotate an endless belt; an inclination adjuster including a cam to adjust inclination of the roller to control deviation of the belt; a belt position detector to detect a belt position in a direction orthogonal to a movement direction of the belt; a stepping motor to rotate the cam; and a control output adjuster to adjust a control output to be supplied to the motor based on the belt position. When obtaining a rotation angle less than one step of the motor, the control output adjuster supplies the control output to the motor for a time corresponding to the rotation angle less than the one step out of a supply time of the control output for obtaining a rotation angle of the one step, and stops supplying the control output for a remaining time out of the supply time.

An imaging system includes a belt roller extending in an axial direction, an endless belt to rotate about the belt roller, a steering roller located inside the endless belt and extending in the axial direction, a steering roller actuator located at an end portion of the belt roller in the axial direction to contact the endless belt, and a support. The steering roller actuator is displaceable in the axial direction in response to a shifting of the endless belt so as to tilt the steering roller with respect to the axial direction. The support supports the endless belt in a gap formed between the belt roller and the steering roller actuator when the steering roller actuator is displaced in the axial direction.

An image forming apparatus includes an image forming portion, a belt, a plurality of stretching rollers including an inner roller and an upstream roller, an outer member, an urging member, a first position changing mechanism, a storing portion, a controller, and an operating portion. The controller controls the first position changing mechanism on the basis of a kind of a recording material on which an image is formed, first set information stored in the storing portion, and first input information for changing setting of a position of the urging member inputted to the controller through the operating portion.

A transfer device includes a transfer roller and a transfer counter roller. The transfer roller has an elastic layer, contacts with and separates from an image bearer including a belt-shaped elastic body, and nips a recording medium with the image bearer. The transfer counter roller has an elastic layer, is disposed facing the transfer roller, and nips the image bearer with the transfer roller. The transfer counter roller or the transfer roller is applied with a bias to transfer the toner image. Each of the elastic layers of the transfer roller and the transfer counter roller has an Asker C hardness of 75 or less. A difference in thickness between the elastic layers of the transfer roller and the transfer counter roller is ±3% or less.

A developing device includes a developing roller, a developing case, and a support. The developing roller includes a sleeve and a magnetic field generator. The sleeve is rotatable and includes a hollow shaft at an axial end of the sleeve. The magnetic field generator is irrotationally disposed inside the sleeve and includes a non-rotating shaft at an axial end of the magnetic field generator. The non-rotating shaft penetrates through the hollow shaft and projects outward. The developing case is configured to store developer and rotatably supports the hollow shaft. The support includes a fitting portion into which the non-rotating shaft of the magnetic field generator is irrotationally fitted. The support is supported on the developing case using the fitting portion as a main-positioning portion.

An image forming apparatus includes a photosensitive member, a developing member to supply a toner to the photosensitive member at a developing portion, a transfer member to transfer a toner image to a recording material passing through a transfer portion from the photosensitive member. In a case which the transfer is performed to a smaller width recording material and thereafter, the transfer is successively performed to a larger width recording material, a control portion controls a first back contrast formed when an area of a surface of the photosensitive member corresponding to the transfer portion through which the smaller width recording material is passing reaches the developing portion, and a second back contrast formed when an area of the surface corresponding to the transfer portion through which the larger width recording material is passing reaches the developing portion so that the second back contrast is larger than the first back contrast.

An image forming apparatus includes a rotatable photosensitive member; a charging portion, an exposure portion, a developing member, a transfer unit, a contact and separation portion, a charging voltage applying portion, a detecting portion, and a controller. The controller is capable of executing an operation in an image forming mode and an operation in a detecting mode. The controller carries out control so that a charging current flowing through a charging portion during charging of the photosensitive member in the operation in the detecting mode is lower than a charging current flowing through the charging portion during charging of the photosensitive member in the operation in the image forming mode.

A sliding bearing is made of a resin and includes a tubular portion that includes an outer peripheral surface including a D-cut surface. A flange portion, which protrudes from the D-cut surface, is formed at one end portion of the tubular portion. An engagement portion is formed at the other end portion of the tubular portion. A protruding portion is formed on the outer peripheral surface of the tubular portion at a circumferential position that is outside a region in which the D-cut surface is formed and that is outside a region in which the engagement portion is formed.

A rotating member control device that controls a first rotating member and a second rotating member to convey a sheet includes a processor configured to execute a program to implement processes of controlling the first rotating member and the second rotating member to come into contact or be separated from each other and acquiring a value that corresponds to or is proportional to a driving torque of a first driving unit that rotationally drives the first rotating member. The processor acquires the value upon separation when the first rotating member and the second rotating member are separated from each other and upon conveyance when the sheet is held between and conveyed by the first rotating member and the second rotating member. The processor further sets a rotational speed of the second rotating member such that the value acquired upon separation and the value acquired upon conveyance become equal.

An image forming apparatus includes: an annular transfer belt to which an image is transferred; a transfer roller that transfers an image to a recording medium when the recording medium passes through a transfer area formed between the transfer roller and the transfer belt; a drive mechanism that causes the transfer roller to rotate; and a speed adjustment mechanism that adjusts a rotational speed of the transfer roller achieved by the drive mechanism in units of a cycle of the transfer roller, and switches between a first adjustment pattern and a second adjustment pattern to execute switched adjustment pattern in a cycle including a state in which the transfer roller transports the recording medium, the first adjustment pattern for adjusting the rotational speed of the transfer roller, the second adjustment pattern for adjusting the rotational speed of the transfer roller with a pattern different from the first adjustment pattern.