| 摘要 |
PURPOSE:To eliminate inconvenience of breakage of a sheet due to a slack of a web or an abrupt tension change and to make the sheet crawl effectively. CONSTITUTION:When a web is slacked during sheet scrawling, a web tension retaining roller 24 is moved in a tension applying direction, while when the web is pulled, the roller 24 is moved in a tension reducing direction. In this case, a difference between a weight of the roller 24 and an output of a web tension regulating mechanism (air cylinder) 30 [an output of web tension regulating mechanism < a weight of a web tension retaining roller] is operated as a tension at the web to retain the web tension constant. |
