Image forming apparatus

An image forming apparatus comprising:

• a main assembly;
• an image forming portion provided to the main assembly and configured to form an image on a sheet;
• a belt conveying device provided to the main assembly and provided with a rotatable endless belt for carrying and conveying the sheet and with a plurality of stretching rollers for stretching the belt, the belt conveying device being movable along a movement direction crossing a conveying direction of the belt between a first position for operating the belt conveying device and a second position on an outside of the main assembly relative to the first position;
• a slide rail configured to movably support the belt conveying device along the movement direction, and extended along the movement direction from the first position toward the second position of the belt conveying device so as to pass through a region enclosed by an inner peripheral surface of the belt;
• a slide rail supporting member configured to support the slide rail and supported by the main assembly on a side upstream of the belt conveying device with respect to the movement direction;
• a supporting beam mounted to the belt conveying device and extended along the movement direction so as to oppose an outer peripheral surface of the belt;
• and
• a rotatable supporting member mounted to the main assembly and configured to support the belt conveying device by supporting the supporting beam when the belt conveying device is moved from the first position toward the second position.