| 摘要 |
<p>PURPOSE:To shorten the deviation controlling width of a belt driving device which is capable of automatically detecting and correcting deviation by allowing the belt drive a smooth operation in correcting deviation. CONSTITUTION:A photosensitive belt 6 is movably stretched across three of first, second and third rollers 3, 4, 5. A deviation detecting member 28 is disposed at one axial end portion of the third roller 5, and when the photosensitive belt 6 deviates and makes contact with the deviation detecting member 28 one of the axial end portions of the third roller 5 is displaced by means of the torque of the deviation detecting member 28 so as to cancel out the initial deviation. The axial end portion of the third roller 5 at which the deviation detecting member 28 is not provided is loosely fittingly supported to a first tension arm 17. During the action to correct the deviation the third roller 5 can thereby be put in pendulum motion about the loosely fitted portion, while the axial end portion of the third roller 5 at which the deviation detecting member 28 is provided is prevented from making contact with a second tension arm 18 for supporting the third roller 5.</p> |
