| 摘要 |
PROBLEM TO BE SOLVED: To easily and inexpensively produce a tubular film having no difference in level in the thickness of an overlapped part in producing the tubular film by overlapping a sheet-like film. SOLUTION: A thermoplastic sheet-like film is wound around a columnar or cylindrical inner mold 1 so that the winding start and end parts thereof are partially overlapped to form an overlapped part and, after the overlapped part is integrated, the whole is inserted into an outer mold 2 having a circular inner diameter made larger than the outer diameter of the inner mold by predetermined quantity and, when the thermoplastic sheet like film 4 wound around the inner mold 1 is heated to bond the overlapped part, a member 3 large in the coefficient of thermal expansion is adapted to the part adjacent to the overlapped part of the sheet-like film wound around the inner mold 1 of at least one of the inner mold 1 and the outer mold 2 to make the thermoplastic sheet-like film tubular. The usefulness of this tubular film as a fixing film and transfer belt of an image forming apparatus is disclosed. |
