| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To suppress shape unevenness and surface defects. <P>SOLUTION: The method includes a step of extruding a tube in approximately the gravitational direction, an air cooling step, a water cooling sizing step, a tube drawing step, and a tube cutting step, and in which the charging member is formed by coating an elastic body layer on the outer periphery of a core bar with a multi-layered seamless tube. In the extruding step, a ratio (draw ratio) d<SB>1</SB>/d<SB>2</SB>of the gap d<SB>1</SB>between a metal mold (nipple) in an exit portion in contact with the coated tube on a side of an internal surface of the coated tube and a metal mold (dies) at an exit portion of the metal mold in contact with the coated tube on a side of an external surface and a wall thickness d<SB>2</SB>after the tube cutting step is 1.0 to 2.0 and the tube drawing step has an arc of at least a pair of the same diameters (R) and is performed by a conveyance means of delivering the tube at the same circumferential speed via at least a pair of contacts with the tube. <P>COPYRIGHT: (C)2007,JPO&INPIT</p> |
