Patent ID: 8064797

Claim:
An image forming apparatus comprising: an image bearing member; a belt member configured to be rotatable and to contact the image bearing member; a belt unit configured to support the belt member and removably mounted on the image forming apparatus; an operation unit disposed on the belt unit; a belt unit moving mechanism configured to cause the belt member to contact the image bearing member when the operation unit is in a first position, and to cause the belt member to separate from the image bearing member when the operation unit is in a second position; a tensile force releasing mechanism configured to release a tensile force applied to the belt member when the belt unit is pulled out from the image forming apparatus and the operation unit is in a third position; and a locking unit configured to lock the belt unit to the image forming apparatus so that the belt unit is not removed from the image forming apparatus, when the operation unit is in the third position while the belt unit is mounted on the image forming apparatus.