A control unit first drives a photosensitive drum at a normal speed that is faster than a low speed, and the control unit subsequently changes the drive speed of the photosensitive drum from the normal speed to the low speed after a transfer belt is brought into contact with the photosensitive drum that is driven at the normal speed.

An image forming apparatus includes: an endless belt; an image bearing member that bears a toner image and contacts with the outer circumferential surface of the belt at a transfer position for transferring the toner image to the belt, the transfer position being disposed downstream; a transfer roller configured to transfer the toner image from the image bearing to the belt and contact with an inner circumferential surface of the belt at a contact position, the contact position does not overlap with the transfer position as viewed from the thickness direction of the belt; a biasing member that biases the transfer toward the inner circumferential surface of the belt, and a position of the transfer roller is set to a balanced position between a biasing force by the transfer roller pressing the inner circumferential surface of the belt and the drag received by the transfer roller from the belt.

An image forming apparatus includes: an image forming unit configured to perform image formation in a first mode, in which image formation is performed by a plurality of image forming stations, or a second mode, in which image formation is performed by a predetermined image forming station among the plurality of image forming stations; and a controller configured to: control the image forming unit to perform a preparation operation in accordance with color mode information; set a restricted operation state in which the controller prohibits the image formation in the first mode and permits the image formation in the second mode when any one image forming station, except for the predetermined image forming station, is incapable of performing image formation; and prevent the image forming unit from performing the preparation operation when the first mode is set as the color mode information and the restricted operation state is set.

An image forming apparatus is configured to, based on a reading result of a test image, generate data that is used to adjust image forming positions of toner images to be formed by an image forming unit, control an image forming position of a first toner image to be formed by the image forming unit in a first contact state based on first data, the first toner image being transferred to a first sheet, and control an image forming position of a second toner image to be formed by the image forming unit in a second contact state based on second data that is different from the first data, the second toner image being transferred to a second sheet, wherein a type of the second sheet is the same type as the type of the first sheet.

A transfer device includes a belt, a transferor, a holder, a biasing member, and a movement mechanism. The transferor is movable to contact the belt. The holder holds the transferor. The biasing member biases the transferor toward the belt. The movement mechanism contacts the holder and causes the transferor to move in a direction opposite to a direction in which the biasing member biases the transferor. The holder includes a contact portion to contact the movement mechanism and a holder portion. The contact portion includes a material having a higher rigidity than the holder portion.

An image forming apparatus of the present disclosure includes a plurality of image forming portions, an intermediate transfer unit, a secondary transfer member, a belt cleaning device, and a control portion. The intermediate transfer unit includes an intermediate transfer belt, a plurality of primary transfer members, a drive roller, a tension roller, and a contacting/separating mechanism. The belt cleaning device includes a cleaning member which faces the tension roller with the intermediate transfer belt therebetween. In a withdrawal mode, the cleaning member is moved by pressing force of the tension roller further into a housing from an opening portion as compared with in a printing mode. The control portion is capable of executing, while image formation is not being performed, a transfer toner collection mode in which the intermediate transfer belt and the belt cleaning device are driven in the withdrawal mode.

An image forming apparatus includes an endless belt that is stretched around plural rollers; a driving unit that drives the belt to rotate; a contact member that is in contact with a part of a surface of the belt, the part being supported by one of the plural rollers; and a switching device that changes an image forming mode by displacing at least one of the plural rollers. When the image forming mode is changed by the switching device, the belt is rotated by the driving unit in a normal direction at a speed higher than a speed of reverse rotation of the roller that is in contact with the contact member with the belt interposed therebetween.

An image forming apparatus includes an endless belt that is stretched around plural rollers; a driving unit that drives the belt to rotate; a contact member that is in contact with a part of a surface of the belt, the part being supported by one of the plural rollers; and a switching device that changes an image forming mode by displacing at least one of the plural rollers. When the image forming mode is changed by the switching device, the belt is rotated by the driving unit in a normal direction at a speed higher than a speed of reverse rotation of the roller that is in contact with the contact member with the belt interposed therebetween.

An image forming apparatus includes: an image forming unit including first and second photosensitive members, and first and second developer carriers; a re-conveyance mechanism configured to convey a recording sheet discharged from the image forming unit towards the image forming unit; a separation/stop mechanism configured to switch a developing unit between an image formation mode in which the first developer carrier contacts the first photosensitive member and a separation mode in which the first developer carrier is separated from the first photosensitive member and the second developer carrier is separated from the second photosensitive member, and a control device configured to switch the developing unit from the image formation mode to the separation mode while the re-conveyance mechanism conveys a first recording sheet after the image forming unit forms an image on a first surface of the first recording sheet.

An image forming apparatus includes an intermediate transfer belt, a plurality of belt rollers, a plurality of transfer rollers, a cleaning member, a first driving portion, a second driving portion, and a running control portion. The first driving portion is capable of causing the respective transfer rollers to come into contact with or separate from the intermediate transfer belt. The second driving portion is capable of changing orientation of predetermined one or a plurality of movable rollers among the plurality of belt rollers. The running control portion executes a running process including: causing the first driving portion to separate the respective transfer rollers from the intermediate transfer belt; causing the second driving portion to change the orientation of the movable roller to orientation different from that during execution of an image forming process; and causing the intermediate transfer belt to run.