Abstract: An image forming apparatus includes a control portion that controls, before performing continuous image formation on a plurality of transfer materials, a voltage to be applied to a primary transfer member for primary transfer during the continuous image formation, and a correction unit that corrects the primary transfer voltage during the continuous image formation. The correction unit can perform a first mode for controlling the primary transfer voltage according to a target value determined by the control portion, and a second mode for changing the target value and controlling the primary transfer voltage according to the changed value. The control portion performs the first mode if a detected electric resistance is a first value or lower, or a second value, greater than the first value, or higher, and performs the second mode if the resistance is higher than the first value and lower than the second value.

Abstract: An image forming apparatus includes a first photosensitive member, having a first outer diameter, a toner image being formed on the first photosensitive member, and a second photosensitive member, having a second outer diameter, a toner image being formed on the second photosensitive member, the second outer diameter being greater than the first outer diameter. A second transfer roller in relation to the second photosensitive member is disposed on a downstream side of a first transfer roller in relation to the first photosensitive member in a conveyance direction of an intermediate transfer belt. A pressing force of the second transfer roller applied to the second photosensitive member is set to be greater than a pressing force of the first transfer roller applied to the first photosensitive member.

Abstract: An image forming apparatus includes a control unit configured to control a cleaning operation of rotating an intermediate transfer member to remove an adjustment toner image, which is formed on an image bearing member and attached to the intermediate transfer member during an adjustment operation, at a cleaning portion where toner is electrostatically removed. The control unit is configured to change the number of times of rotating the intermediate transfer member to convey the adjustment toner image on the intermediate transfer member to the cleaning portion according to at least one of a density and a length in a conveyance direction of the intermediate transfer member regarding the adjustment toner image on the intermediate transfer member before being conveyed to the cleaning portion.

Abstract: An image forming apparatus includes a control unit configured to control a cleaning operation of rotating an intermediate transfer member to remove an adjustment toner image, which is formed on an image bearing member and attached to the intermediate transfer member during an adjustment operation, at a cleaning portion where toner is electrostatically removed. The control unit is configured to change the number of times of rotating the intermediate transfer member to convey the adjustment toner image on the intermediate transfer member to the cleaning portion according to at least one of a density and a length in a conveyance direction of the intermediate transfer member regarding the adjustment toner image on the intermediate transfer member before being conveyed to the cleaning portion.

Abstract: An image forming apparatus includes a first photosensitive member, having a first outer diameter, a toner image being formed on the first photosensitive member, and a second photosensitive member, having a second outer diameter, a toner image being formed on the second photosensitive member, the second outer diameter being greater than the first outer diameter. A second transfer roller in relation to the second photosensitive member is disposed on a downstream side of a first transfer roller in relation to the first photosensitive member in a conveyance direction of an intermediate transfer belt. A pressing force of the second transfer roller applied to the second photosensitive member is set to be greater than a pressing force of the first transfer roller applied to the first photosensitive member.

Abstract: An image forming apparatus includes a control portion that controls, before performing continuous image formation on a plurality of transfer materials, a voltage to be applied to a primary transfer member for primary transfer during the continuous image formation, and a correction unit that corrects the primary transfer voltage during the continuous image formation. The correction unit can perform a first mode for controlling the primary transfer voltage according to a target value determined by the control portion, and a second mode for changing the target value and controlling the primary transfer voltage according to the changed value. The control portion performs the first mode if a detected electric resistance is a first value or lower, or a second value, greater than the first value, or higher, and performs the second mode if the resistance is higher than the first value and lower than the second value.

Abstract: An image forming apparatus includes a first photosensitive drum having a first outer diameter, a second photosensitive drum having a second outer diameter larger than the first outer diameter, an intermediate transfer belt, a first primary transfer roller, a second primary transfer roller, and a cleaning unit configured to electrostatically remove toner attached to the intermediate transfer belt, and can perform a first image forming mode, in which the first and second photosensitive drums and the intermediate transfer belt contact each other, and a second image forming mode in which the first photosensitive drum and the intermediate transfer belt are separated from each other, and a pressing force applied from the second primary transfer roller to the second photosensitive drum is larger than a pressing force applied from the first primary transfer roller to the first photosensitive drum.