Patent ID: 8874002
Filing Date: 2014-10-28
Classification: G03G

Abstract:
1. A belt member driving device comprising: a movable belt member; a tension roller configured to stretch the belt member; a driving source configured to drive the belt member; a steering roller configured to stretch the belt member and to be able to incline relative to the tension roller to move the belt member being driven in a width direction of the belt member; an arm configured to be movable with movement of the belt member in the width direction thereof while being in contact with an end of the belt member in the width direction thereof; a first detected portion provided on the arm; a second detected portion provided on the arm and disposed in a position different from that of the first detected portion in a direction perpendicular to a movement direction of the arm on a plane where the arm is moved; a first sensor configured to detect the first detected portion; a second sensor configured to detect the first detected portion, wherein the second sensor is disposed in a position different from that of the first sensor in the movement direction of the arm as viewed in a direction perpendicular to the movement direction of the arm; a third sensor configured to detect the second detected portion, wherein the third sensor is disposed between the first sensor and the second sensor in the movement direction of the arm as viewed in a direction perpendicular to the movement direction of the arm; and a control unit configured to control inclination of steering roller based on detection results by the first sensor, the second sensor, and the third sensor.