| 摘要 |
PURPOSE:To prevent the breakage of a belt member by constituting either of an image carrying means and a transfer material carrying means of an endless belt member and a belt holding mechanism and forcibly giving biasing force to the belt member so that the belt member may be driven within a fixed position. CONSTITUTION:This device is provided with plural rotatable belt holding mechanisms 4-7 disposed a specified distance apart and the endless belt member 1 movably held by the mechanisms 4-7. A mark 2 is put on the belt member 1 and a mark detection means 130 is provided along a direction intersecting the moving direction of the member 1. Based on an output signal from the means 130, the relative positions of the mechanisms 4-7 are forcibly variably adjusted, and image forming timing for the respective image carriers 61-64 is adjusted based on the moving quantity or the moving speed of the mark 2 in the direction intersecting the moving direction of the belt member 1. Namely, the biasing force is forcibly given to the belt member 1, which is driven within the fixed moving range. Thus, the breakage of the belt member 1 is prevented. |
