| 摘要 |
PURPOSE:To keep web tension constant and to maintain an estimate for a multicolor printing by displacing a floating roll disposed between an in-feed roll and a printing drum corresponding to fluctuations in web tension. CONSTITUTION:When tension of a web 11 increases, the web 11 is elongated to decrease the length of the web passing through an in-feed roll 5 and the length of the web 11' between the in-feed roll 5 and the printing drum 4 is integrally decreased, so that the tension of the web 11' is increased. A floating roll 12 which is unbalanced with tension of a spring 16 by an increase in tension of the web 11' is oscillated against the tension of the spring 16 to a position for balancing with tension increased for a change in length of the web 11' corresponding to an elongation percantage of paper, so that the length of the web 11' is controlled. Thus, the tension of the web 11' between the in-feed roll 5 and the printing drum 4 is kept constant to avoid a change in an estimate for multicolor printing. |
