Patent ID: 6842602
Filing Date: 2005-01-11
Classification: G03G

Abstract:
1. A device for controlling drive of an endless movable member, said device comprising: mark sensing means for sensing at least two pairs of marks each separated from one another at preselected intervals and another pair of marks separated by a distance greater than the preselected intervals, the at least two pair of marks and the another pair of marks continuously positioned on the endless movable member in a direction of movement of said movable member; speed/position control means for controlling either one of a speed and a position of the moveable member by using an output of said mark sensing means; and discontinuity sensing means for determining whether or not a discontinuous portion is present in a sensing region assigned to said mark sensing means, the discontinuous portion arranged at least between the another pair of marks, wherein said speed/position control means is configured to vary speed control or position control in accordance with an output of said discontinuity sensing means.