Roll manufacturing method

摘要

One end of a belt-like fiber material is longitudinally sewn by a sewing machine using a sewing thread. The tensile strength of a bobbin thread is preferably higher than that of a needle thread. In this state, one end of the belt-like fiber material is sewn while being drawn by the bobbin thread, whereby the longitudinal length of the sewn end becomes shorter than that of the other end. As a result, the belt-like fiber material forms a circular arc with the inside surface of the arc being formed by the sewn end while the outside surface of the arc being formed by the other end. The circular arc shaped by the sewn belt-like material is then mounted on a roll shaft in such a manner that the thick face of the sewn end comes in contact with the roll shaft.