STAMPER PLATE REMOVING DEVICE FOR MOLD FOR INJECTION MOLDING OF OPTICAL DISC BASE

摘要

PROBLEM TO BE SOLVED: To facilitate removal of a stamper plate by generating no attracting force between a parmanent magnet of a disc cavity plate on the fixed side and a cavity ring when the cavity ring is at the second angular position and generating an attracting force to a parmanent magnet of a disc cavity plate on the movable side. SOLUTION: The end face part of a cavity ring 17 except a blind hole 20 is laminated on a parmanent magnet 23 of a disc cavity plate 16 on the movable side by rotating manually by using a handle of the cavity ring 17 and the blind hole 20 is made to coincide with the position of a parmanent magnet 22 of a disc cavity plate 15 on the fixed side. The magnetic attracting force of the parmanent magnet 22 of the disc cavity plate 15 on the fixed side is made thereby not to act on the cavity ring 17 face and the cavity ring 17 is attracted on the disc cavity plate 16 on the movable side by the magnetic attracting force of the parmanent magnet 23 of the disc cavity plate 16 on the movable side.