Patent ID: 7856195

Claim:
An image forming apparatus for forming an image on a recording material, comprising: an image bearing member; a driving source; a first pulley rotatable by driving power of said driving source; a second pulley, for transmitting driving power of said driving source to said image bearing member; a belt supported by said first pulley and said second pulley; a first pressing pulley which is disposed upstream from said first pulley with respect to a rotational direction of said belt so as to press said first pulley through said belt, wherein a rotation axis of said first pressing pulley is provided between a rotation axis of said first pulley and a rotation axis of said second pulley with respect to a direction of a line connecting the rotation axis of said first pulley and the rotation axis of said second pulley; a second pressing pulley disposed at a position substantially symmetrically opposite from said first pressing pulley with respect to the line connecting the rotation axis of said first pulley and the rotation axis of said second pulley so as to press said first pulley through said belt; a first spring for pressing a first supporting member, for supporting said first pressing pulley, against said belt member so that said first pressing pulley presses said first pulley through said belt; and a second spring for pressing a second supporting member, for supporting said second pressing pulley, against said belt member so that said second pressing pulley presses said first pulley through said belt, wherein said first pressing pulley and said second pressing pulley press said first pulley through said belt at the same time so that a pressing force toward said first pulley by said first pressing pulley and a pressing force toward said first pulley by said second pressing pulley are canceled out with each other with respect to a direction perpendicular to the line connecting the rotation axis of said first pulley and the rotation axis of said second pulley.