| 摘要 |
PURPOSE:To prevent generation of creases in a sheet material and breakage of the sheet material by rotating a free roll near the peripheral velocity of a driving roll when the free roll separates from the driving roll, and detaching the free roll from driving means just before pressing, whereby after pressing, the peripheral velocity of the free roll is matched with that of the driving roll in a short time. CONSTITUTION:When a free roll 2 separates from a driving roll 1, a pulley 3 of a free roll 2 is pressed to a belt 5 driven by a driving pulley 6 so that the free roll 2 is rotated. When the free roll 2 is pressed to the driving roll 1 from such condition, the pulley 3 is separated from the belt 5, and the free roll 2 is rotated by rotation of the driving roll 1. As the free roll 2 is thus previously rotated before the roll 2 is pressed to the driving roll 1, there is a small difference in peripheral velocity between the roll 2 and the driving roll 1. Accordingly, the peripheral speed of the free roll 2 becomes equal to that of the driving roll 1 with a little speed change. Thus, a sudden speed change is not caused at the time of pressing to prevent breakage of a sheet material, and the generation of creases in the sheet material, and to prevent abrasion of the rolls.
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