Image forming apparatus

An image forming apparatus comprising:

• an apparatus main body;
• a first unit including a photosensitive drum, the first unit being movable between an inside and an outside of the apparatus main body and including a first wall surface provided at one end portion in a rotation axis direction of the photosensitive drum;
• and
• a second unit including a belt configured to contact with the photosensitive drum, the second unit being movable between the inside and the outside of the apparatus main body while the first unit is inside the apparatus main body,
• wherein the first unit and the second unit are movable to the outside of the apparatus main body in a state in which the first unit and the second unit are coupled to each other, and
• wherein in the state in which the first unit and the second unit are coupled to each other, the first wall surface is located outward of the belt in the rotation axis direction, and a lower end portion of the first wall surface in a vertical direction is located below a contact surface of the belt that comes into contact with the photosensitive drum.