An image forming apparatus that forms an image on a recording material, comprising:
- a first image forming portion including a rotatable first image bearing member and a first charging device configured to charge the first image bearing member by a plurality of corona chargers including a first corona charger having a first discharge electrode and a first grid electrode and disposed at a most upstream position with respect to a rotation direction of the first image bearing member, and a second corona charger having a second discharge electrode and a second grid electrode and disposed at a most downstream position in the rotation direction of the first image bearing member, the first image forming portion being configured to form a toner image on the first image bearing member;
- a second image forming portion including a rotatable second image bearing member and a second charging device configured to charge the second image bearing member by a plurality of corona chargers including a third corona charger having a third discharge electrode and a third grid electrode and disposed at a most upstream position with respect to a rotation direction of the second image bearing member and a fourth corona charger having a fourth discharge electrode and a fourth grid electrode and disposed at a most downstream position in the rotation direction of the second image bearing member, the second image forming portion being configured to form a toner image on the second image bearing member;
- an intermediate transfer member which is disposed so as to be in contact with each of the first image bearing member and the second image bearing member and to which the toner image formed on the first image bearing member is transferred;
- and
- a controller configured to control each of the first image forming portion and the second image forming portion so that a monochrome image forming mode, in which, in a state in which the intermediate transfer member is in contact with each of the first image bearing member and the second image bearing member and in a state in which each of the first image bearing member and the second image bearing member is rotationally driven, the first image forming portion forms a toner image on the first image bearing member and the second image forming portion does not form a toner image on the second image bearing member, thereby forming an image on the recording material, is executed,
- wherein, in the monochrome image forming mode,
- an absolute value of a first voltage lower than a minimum value of absolute values of a plurality of voltages applied to the plurality of grid electrodes of the first image forming portion and higher than an absolute value of a target potential of a surface of the second image bearing member in the monochrome image forming mode is applied to one of the plurality of grid electrodes of the second image forming portion, and
- no voltage is applied to other grid electrodes except the grid electrode to which the first voltage is applied among the plurality of grid electrodes of the second image forming portion.