| 摘要 |
PROBLEM TO BE SOLVED: To provide a blow molding method, with which positions, at which no preform exists, are specified so as to allow to stop blow molding at the specified positions and prevent the wastes of other preforms and of compressed air and further noises from developing under the condition that a plurality of the preforms are simultaneously blow-molded. SOLUTION: This blow molding method is to simultaneously blow-mold a plurality of performs 20, which are conveyed to a blow molding part by means of conveying members 36 corresponding to the individual preforms 20. This blow-molding method contains a process for arranging a first and a second photoelectric switches 52 and 54 just before the blow-molding part, a process for detecting the past conveying member 36 with the first photoelectric switch 52, a process for detecting the presence or absence of the part preform 20 with the second photoelectric switch 54 and a process, in which positions, in which no preform 20 exists, of simultaneously formed preforms are specified on the basis of the detection results of the first photoelectric switch 52 and those of the second photoelectric switch 54 so as to stop blowing air to the blowing cavities corresponding to the specified positionsand supply the blowing air to the remaining blowing cavities for blow molding. |
