When a drive roller is at a stopped state, an execution portion executes a move mode in which a time from when a rotation of a drive roller has been stopped is measured, and based on the measured result, rotation of the drive roller is started and stopped. In the move mode, a portion of a secondary transfer belt having been at a first contact position in the stopped state is moved to a position other than the first contact position and the second contact position, and the rotation of the drive roller is stopped.

An image forming apparatus includes an image bearing member that bears a toner image, a transfer unit having an endless belt, a positioning unit that positions the transfer unit, and a secondary transfer member. The secondary transfer member is in touch with the endless belt to form a secondary transfer portion. When the toner image is transferred to the endless belt from the image bearing member, the secondary transfer member transfers the toner image from the endless belt at the secondary transfer portion to a transfer material. The positioning unit includes a first abutting face to position the transfer unit in a conveyance direction and a second abutting face to position the transfer unit in a direction opposite to the conveyance direction. An attaching/detaching direction of the transfer unit is a direction intersecting with a surface of the transfer material to which the toner image is transferred.

The crystallinity of a thermoplastic resin is 8% or more and 25% or less, the average primary particle size of carbon black is 10 nm or more and 30 nm or less, the content of the carbon black is 15.0 parts by mass or more and 30.0 parts by mass or less with respect to 100 parts by mass of an intermediate transfer belt, and (Li+Lo+Lc)/3≤100 nm, where Li, Lo, and Lc are values of an L-function indicating a dispersibility of the carbon black with respect to the thermoplastic resin in an inner peripheral surface region of the intermediate transfer belt, in an outer peripheral surface region, and in a central region that is a central portion of the intermediate transfer belt in a thickness direction of the intermediate transfer belt, respectively.

An endless belt includes: a resin; and electrically conductive particles, wherein an integrated discharge amount is 350 μC or less. The integrated discharge amount is determined by disposing an electrode at a position spaced 60 μm apart from the outer circumferential surface of the belt, applying a voltage to the electrode, and measuring the amount of discharge for a period of 1 second after the voltage reaches 1300 V.

An image forming apparatus includes an intermediary transfer belt, stretching rollers a pressing member, a supporting member, a moving mechanism, and a controller. In a case that in an operation in a toner image transfer mode is executed for recording materials of a predetermined kind in a predetermined environmental condition, when a sum of times each in which the operation was executed from a new state of the pressing member is a first time, a position of the supporting member during execution of the operation in the mode is a first position, and when the sum is a second time longer than the first time, the position of the supporting member during the execution of the operation is a second position where the pressing member is moved in a direction in which the pressing member presses the belt more than in the first position.

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.

A transfer device includes: an endless member in an endless shape that orbits; primary transfer members that are respectively arranged on an opposite side of plural image holding bodies disposed side by side in a circumference direction of the endless member with the endless member interposed between the primary transfer member and the image holding body, and transfer an image held by the image holding body to the endless member; a secondary transfer member that transfers the image transferred to the endless member to a recording medium; an applying roll around which the endless member is wound, that is disposed on a downstream side of all the primary transfer members and on an upstream side of the secondary transfer member in the circumference direction, and that urges the endless member from an inner peripheral surface of the endless member to apply tension to the endless member; an upstream roll around which the endless member is wound, and that is disposed on the downstream side of all the primary transfer members and on an upstream side of the applying roll in the circumference direction; a contact and detachment member that moves at least some of the plural primary transfer members, and contacts and detaches the endless member and the image holding body to change a posture of the endless member; a detection member that faces a portion of the endless member between the upstream roll and the applying roll to detect the image transferred to the endless member; and a positioning mechanism that changes a posture of the detection member according to the change in the posture of the endless member to position the detection member at the endless member.

An image forming apparatus includes a conveyance unit that conveys a recording medium in contact with one surface of the recording medium along a conveyance path; a first image forming group that is provided on the other surface side of the recording medium in the conveyance path, and includes plural image forming sections that form a toner image; a second image forming group that is provided on a downstream side in a conveyance direction of the first image forming group on the other surface side of the recording medium in the conveyance path, and includes plural image forming sections that form a toner image; a first intermediate transfer body that is provided on the downstream side in the conveyance direction of the first image forming group, and to which the toner image formed by the plural image forming sections of the first image forming group is primarily transferred; a second intermediate transfer body that is provided on an upstream side in the conveyance direction of the second image forming group, and to which the toner image formed by the plural image forming sections of the second image forming group is primarily transferred; a first transfer unit that secondarily transfers the toner image from the first intermediate transfer body to the other surface of the recording medium conveyed by the conveyance unit; and a second transfer unit that secondarily transfers the toner image from the second intermediate transfer body to the other surface of the recording medium conveyed by the conveyance unit.

A belt drive device includes a drive unit, a detection unit, a blade, and a control unit. The drive unit rotates an endless belt. The detection unit detects a position of a connection portion in which both ends of a reinforcing tape, which is provided on an outer surface of an edge of the belt in a width direction orthogonal to a rotation direction of the belt, in a longitudinal direction along the edge of the belt are overlapped and connected. The blade comes into contact with an outer surface of the belt and an outer surface of the reinforcing tape and is provided to extend in the width direction. The control unit controls driving of the drive unit based on a detection result obtained by the detection unit such that when the drive unit rotates the belt by a constant length in a reverse direction from one end of the reinforcing tape overlapped inside toward the other end of the reinforcing tape overlapped outside at the connection portion from a state in which the belt is stopped, the drive unit rotates the belt in a forward direction to a rotation position where the other end of the reinforcing tape does not come into contact with the blade by a reverse rotation and stops the belt before the belt is reversely rotated.

An endless belt includes a resin, and particles having an average primary particle diameter of 8 nm or more and 20 nm or less. In a volume frequency distribution of the particles determined by small-angle X-ray scattering measurement, the ratio (area B/area A) of graph area B of a particle diameter region of over 35 nm to graph area A of a particle diameter region of 35 nm or less is 0.3 or less.