The present disclosure is directed to suppressing image defects due to variations in the values of currents flowing through respective photosensitive drums during image formation, and reducing the absolute value of a voltage applied when a primary transfer power supply unit applies a voltage of polarity opposite to that during image formation, to primary transfer members. There is provided an image forming apparatus including a transfer member configured to make contact with an inner peripheral surface of a transfer belt, a first power supply unit configured to apply a voltage to the transfer member, a resistance element connected between the first power supply unit and the transfer member, and a diode connected in parallel with the resistance element in a direction in which a current flowing in a first direction is blocked and a current flowing in a second direction is passed.

An image forming apparatus includes a photoconductor, an exposure device, and a shutter assembly. The exposure device includes a light source configured to expose the photoconductor. The light source is repositionable between a proximity position at a first distance from the photoconductor and a separation position at a second distance from the photoconductor. The first distance is less than the second distance. The shutter assembly is configured to move away from the light source in response to the light source moving toward the proximity position. The shutter assembly is configured to move to cover the optical path of the light source in response to the light source moving toward the separation position.

In an image forming mode, in which a first image forming portion forms a toner image on a first image bearing member and a second image forming portion does not form a toner image on a second image bearing member, thereby forming an image on a recording material, a first voltage lower than a minimum value of absolute values of a plurality of voltages applied to a 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 image forming mode is applied to one of a plurality of grid electrodes of the second image forming portion, and no voltage is applied to the 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.

An image forming apparatus includes a plurality of photosensitive members; a scanner unit including light sources, a rotatable polygonal mirror, and reflecting members; and a fixing portion. Parts of the laser beams emitted from the light sources are reflected by the rotatable polygonal mirror toward the fixing device side, and rest parts of the laser beams are reflected by the rotatable polygonal mirror toward a side opposite from the fixing device side. Of the parts of the laser beams reflected by the rotatable polygonal mirror toward the fixing device side, the laser beam reflected toward the reflecting member provided at a position remotest from the rotatable polygonal mirror travels downward relative to a horizontal direction. A rotational axis of the rotatable polygonal mirror is inclined relative to a vertical direction.