This patent specification describes an image forming apparatus which includes a first member having a surface endlessly moving in a specific direction a second member having a surface endlessly moving in the specific direction at a region facing the surface of the first member, and a supporting member to hold the second member and to move together with the second member. The supporting member includes a release mechanism to release an engagement of the supporting member from the second member. Further, a pressing member is included to press the second member via the supporting member to cause the second member to contact the first member under pressure to form a nip between the first and second members. The release mechanism releases the engagement of the supporting member from the second member when the second member is pushed away by a leading edge of a recording medium having a thickness greater than a reference thickness value.