Mold device, injection molding system and method for manufacturing molded article

A mold device, comprising:

• a shaft mechanism that is provided on at least one of a first mold and a second mold, the first mold and the second mold forming a molding space having a nested structure;
• and
• an ejection portion that is provided on at least one of the first mold and the second mold, the ejection portion ejecting a pressurized fluid from an ejection device to the molding space for letting the pressurized fluid enter a clearance between a resin and a cavity of the mold device to pressurize the resin during an injection of the resin or after the injection of the resin, wherein
• the shaft mechanism includes:
• a shaft body for extruding a molded article that is molded from the resin injected into the molding space;
• a ring-shaped elastic member for supporting the shaft body, an opening of a groove formed in a circumferential direction of the ring-shaped elastic member being oriented toward the molding space;
• and
• a ring-shaped member fitted into the opening of the groove of the ring-shaped elastic member, wherein
• the ejection device has a pressurization pin or a pressurization ejector pin,
• the pressurization pin or the pressurization ejector pin has a multiple structure including an outer cylinder, the outer cylinder having a passage of the pressurized fluid inside the outer cylinder,
• at least the outer cylinder of the pressurization pin or the outer cylinder of the pressurization ejector pin is configured to move backward before fluid pressurization to make a space between the ejection portion and the resin so that the fluid pressurization is carried out toward the space, the ejection portion being formed at a tip of the pressurization pin or the pressurization ejector pin.