Belt feeding device and image forming apparatus

An image forming apparatus comprising:

• an image forming portion configured to form a toner image;
• a belt unit provided with an endless belt to which the toner image formed by the image forming portion is transferred in a first transfer portion, the belt transferring the toner image transferred thereto from the belt to a recording material in a second transfer portion;
• a fixing device disposed above the second transfer portion with respect to a vertical direction and configured to fix the toner image transferred to the recording material to the recording material;
• and
• an upper feeding path configured to feed the recording material upward from an accommodating portion for accommodating the recording material to the fixing device via the second transfer portion,
• wherein the belt unit comprises:
• a plurality of stretching rollers, including a tension roller, configured to stretch the belt;
• a first bearing member configured to rotatably support the tension roller in one end portion thereof with respect to a rotational axis direction of the tension roller;
• a second bearing member configured to rotatably support the tension roller in the other end portion thereof with respect to the rotational axis direction;
• a first bearing support member configured to movably support the first bearing member with respect to a direction crossing the rotational axis direction;
• a second bearing support member configured to movably support the second bearing member with respect to a direction crossing the rotational axis direction;
• a first urging member provided between the first bearing member and the first bearing support member and configured to urge the tension roller to apply tension to the belt;
• a second urging member provided between the second bearing member and the second bearing support member and configured to urge the tension roller to apply tension to the belt;
• a supporting member configured to support the first bearing support member and the second bearing support member;
• a first locking member movably provided between a first locked position where the first bearing member is locked and a first unlocked position where the first bearing member is unlocked and capable of locking the first bearing member by engaging with the first bearing support member and the first bearing member;
• and
• a second locking member movably provided between a second locked position where the second bearing member is locked and a second unlocked position where the second bearing member is unlocked and capable of locking the second bearing member by engaging with the second bearing support member and the second bearing member;
• wherein the first locking member is movably provided between the first locked position and the first unlocked position in a state in which the second locking member is positioned in the second locked position.