Patent ID: 8702097

Claim:
An image forming apparatus configured to form an image on a sheet, the image forming apparatus comprising: an endless belt; a driving roller which is configured to rotationally drive the belt; a driven roller which is configured to be rotationally driven with the rotation of the belt, wherein the belt has an extension surface defined by a flat region between the driving roller and the driven roller; a frame which supports the driving roller and the driven roller; a bearing member which is provided to the frame to be displacable, and rotatably supports the driven roller; a tension generating member including a spring which is configured to generate an urging force to generate a tension at the belt; a displacement member which is provided to be displacable in a displacement direction parallel to an axial direction of the driven roller, and which is displaced in the displacement direction together with the belt when the belt is moved in a moving direction along the displacement direction during the rotation of the belt; and an axial force converting unit which is configured to convert a force of displacing the displacement member into a force which is directed in a direction intersecting the displacement direction and causes the tension generated at the belt to change such that a ratio of a tension generated on a trailing side in the moving direction of the belt to a tension generated on a leading side in the moving direction of the belt is decreased, wherein the axial force converting unit does not cause the driven roller to become inclined relative to the extension surface, wherein the axial force converting unit includes an arm member including: a first arm portion configured to receive a force parallel to the axial direction of the driven roller from the displacement member; and a second arm portion which extends in a direction intersecting an extending direction of the first arm portion, and which is configured to apply a force to the driven roller, wherein the arm member is swingably provided to the frame, wherein the spring of the tension generating member contacts the bearing member at a first position to apply the urging force to the driven roller, and wherein the second arm portion of the arm member contacts the bearing member at a second position different from the first position to apply the force to the driven roller.