Image forming apparatus

An image forming apparatus, comprising:

• an image bearing member configured to bear a toner image;
• a main body having an apparatus body frame;
• a positioning portion provided in the apparatus body frame;
• a removable belt unit configured to be engaged with the positioning portion so as to be positioned in the main body, the belt unit including a belt configured to transfer the toner image from the image bearing member onto a recording material, first and second stretching members configured to stretch an inner face of the belt, a third stretching member configured to stretch the inner surface of the belt so as to apply tension to the belt, and a belt frame configured to hold the first, second, and third stretching members;
• and
• a pressure removing member configured to move the third stretching member from a first position to apply the tension to the belt to a second position to remove the tension from the belt,
• wherein, after the belt unit is positioned in the main body by engaging the first and second stretching members with the positioning portion of the apparatus body frame in a state in which the third stretching member is placed at the second position by the pressure removing member, the tension is applied to the belt by moving the third stretching member from the second position to the first position by the pressure removing member.