Abstract
Thin and flexible materials such as paper, optical film and metallic lamina are called web. In recent years, the market of optical film is increasing. Therefore, it is very important to improve productivity of web. The web is produced by Roll to Roll producing system. Today, engineers hope to prevent defect such as slippage and wrinkle under transport system. However, web is occurred wrinkles easily due to change more thin and wide. It is knowledge that using concave rollers with web spreading effect to prevent wrinkles. But, there are few papers written about spreading effect by concave rollers. So we researched web spreading effect by concave rollers. As a result, concave rollers are effectively web spreading and change of roller's shape affect spreading effect.
