Patent ID: 8115143

Claim:
A drying apparatus for drying web, comprising: at least one thermal roll for transporting and heating said web, said thermal roll including a roll surface, having a static friction coefficient μ defined by contact with said web, wherein said static friction coefficient μ satisfies a condition of: t+V≦G wherein G = ⁢ μ · σ A ⁢ ⁢ 1 = ⁢ μ · t · sin ⁡ ( θ / 2 ) where t is tension applied to said web; G is roll retaining force caused by friction with which said thermal roll retains said web; V is thermal expansion force generated by thermal expansion of said web retained on said thermal roll; σ A1 is pressing force caused by said tension to said web and applied to said roll surface by said web; θ is a wrap angle at which said web contacts said thermal roll.