Method for producing hollow molded article and injection stretch blow molding machine

A method for producing a hollow molded article using an injection stretch blow molding machine in which an injection molding section having an injection molding mold, which includes a combination of an upper mold, a lower mold, and a lip mold, and a blow molding section having a blow molding mold, which includes a combination of a blow mold and the lip mold, are disposed on a base plate, and in which a plurality of hollow molded article producing processes are performed simultaneously, the hollow molded article producing process including:

• an injection molding process of injection molding a preform in an injection molding section;
• a blow molding process of blow molding a hollow molded article from the preform in a blow molding section wherein the blow molding section includes:
• a blowing apparatus including a mold clamping mechanism configured to open and close the blow molding mold;
• and
• a blowing apparatus positioning stopper configured to press the blowing apparatus laterally in a direction along a mounting surface of the base plate on which the blowing apparatus is mounted, the blowing apparatus is positioned by the blowing apparatus positioning stopper so that a lip mold arrangement position in the blow molding mold where a high-pressure mold clamping force is applied in the direction along the mounting surface of the base plate on which the blowing apparatus is mounted corresponds to a lip mold lowering position in the blow molding section;
• when the injection molding process in a first hollow molded article producing process among the plurality of hollow molded article producing processes is performed in the injection molding section, the blow molding process in a second hollow molded article producing process prior to the first hollow molded article producing process is performed in the blow molding section;
• and
• the high-pressure mold clamping force in the direction along the mounting surface of the base plate on which the blowing apparatus is mounted is applied to the blow molding mold of the blowing apparatus which has been positioned so as to correspond to the lip mold lowering position to perform a blow mold high-pressure switching step during the blow molding process in the second hollow molded article producing process within a time from start of an injection mold opening step during the injection molding process to completion of the injection mold high-pressure switching step.