| 摘要 |
PROBLEM TO BE SOLVED: To highly accurately and stably manufacture a roller made of electrically conductive foam at low cost by a method wherein a difference is provided between the outer diameter at the middle part and the end part of a cylindrical molding tool having covering bodies, each of which holds a core metal member concentrically, at both the ends of the cylindrical molding metal mold. SOLUTION: In a metal mold 10, the middle part of which has a constant diameter over a certain length and the remaining part of which the diameter linearly reduces towards the end of the mold, core metal holding members 11, which can hold a rubber material before expansion and vulcanization around a core metal, are provided concentrically at the end parts of the metal mold 10. The core metal holding member 11 is equipped with a vent hole 13. By putting a metal mold, in which the material has already charged, in a heating plate for heating, both the vulcanization and expansion of the rubber material are executed simultaneously. At the end part of the mold, the temperature rise is very slow due to no contact of the material with the heating plate, resulting in advancing the vulcanization and expansion from the middle part to the end part. As a result, the gas developing at expansion escapes fully and a highly accurate foamed roller can be stably manufactured even with the metal mold. |
