A plasticizing device includes: a flat screw that has a groove forming surface on which a spiral first groove is formed, and that rotates; a barrel that has a facing surface facing the groove forming surface and that includes a communication hole through which a plasticizing material flows; a heater that heats resin pellets; and a screw case that accommodates the flat screw and that includes a passage port through which the resin pellets pass toward the flat screw, in which the flat screw has a first side surface on which a first supply port for supplying the resin pellets to the first groove is formed and a second side surface formed on a side farther from the barrel than the first side surface, and a first distance, which is a shortest distance between the first side surface and the screw case, is larger than a second distance, which is a shortest distance between the second side surface and the screw case.

A plasticizing device includes: a flat screw that has a groove forming surface on which a spiral first groove is formed, and that rotates; a barrel that has a facing surface facing the groove forming surface and that includes a communication hole through which a plasticizing material flows; a heater that heats resin pellets; and a screw case that accommodates the flat screw and that includes a passage port through which the resin pellets pass toward the flat screw, in which the flat screw has a first side surface on which a first supply port for supplying the resin pellets to the first groove is formed and a second side surface formed on a side farther from the barrel than the first side surface, and a first distance, which is a shortest distance between the first side surface and the screw case, is larger than a second distance, which is a shortest distance between the second side surface and the screw case.

An injection unit includes an injection cylinder and a plasticizing screw in the injection cylinder. The plasticizing screw is rotatable about a longitudinal axis for plasticizing plastic raw material and is movable linearly along the longitudinal axis for injecting molten plastic raw material. The injection cylinder has an infeed and plasticizing zone for the plastic raw material with a circular-cylindrical inner wall with a constant diameter along the longitudinal axis, a metering zone in front of the infeed and plasticizing zone along the longitudinal axis in the injection direction with a circular-cylindrical inner wall with a constant diameter along the longitudinal axis, and a nozzle head in front of the metering zone in the injection direction with a nozzle-shaped inner wall. The diameter of the circular-cylindrical inner wall of the metering zone is smaller than the diameter of the circular-cylindrical inner wall of the infeed and plasticizing zone.

An injection unit includes an injection cylinder and a plasticizing screw in the injection cylinder. The plasticizing screw is rotatable about a longitudinal axis for plasticizing plastic raw material and is movable linearly along the longitudinal axis for injecting molten plastic raw material. The injection cylinder has an infeed and plasticizing zone for the plastic raw material with a circular-cylindrical inner wall with a constant diameter along the longitudinal axis, a metering zone in front of the infeed and plasticizing zone along the longitudinal axis in the injection direction with a circular-cylindrical inner wall with a constant diameter along the longitudinal axis, and a nozzle head in front of the metering zone in the injection direction with a nozzle-shaped inner wall. The diameter of the circular-cylindrical inner wall of the metering zone is smaller than the diameter of the circular-cylindrical inner wall of the infeed and plasticizing zone.

An injection device has a screw disposed in a heating cylinder so as to be rotatable and movable in an axial direction. An injection stage supports the heating cylinder. A material supplying unit supplies a resin material to the heating cylinder. A material introducing member is disposed between the material supplying unit and the heating cylinder and introduces the resin material from the material supplying unit to the heating cylinder, The material introducing member has a cylindrical portion fitted in a vertical hole provided in the injection stage, and a lower part of the cylindrical portion is in abutting contact with the heating cylinder. A heat medium passage extends inside a sidewall of the cylindrical portion for flowing therethrough a temperature-controlled heat medium, and a heat-insulating air space is formed between an outer circumferential surface of the cylindrical portion and a circumferential surface of the vertical hole.

An injection device has a screw disposed in a heating cylinder so as to be rotatable and movable in an axial direction. An injection stage supports the heating cylinder. A material supplying unit supplies a resin material to the heating cylinder. A material introducing member is disposed between the material supplying unit and the heating cylinder and introduces the resin material from the material supplying unit to the heating cylinder, The material introducing member has a cylindrical portion fitted in a vertical hole provided in the injection stage, and a lower part of the cylindrical portion is in abutting contact with the heating cylinder. A heat medium passage extends inside a sidewall of the cylindrical portion for flowing therethrough a temperature-controlled heat medium, and a heat-insulating air space is formed between an outer circumferential surface of the cylindrical portion and a circumferential surface of the vertical hole.

A method for producing a foam-molded product uses a producing apparatus including a plasticizing cylinder. The plasticizing cylinder has a plasticization zone, a starvation zone, and an introducing port which is formed in the plasticizing cylinder and via which a physical foaming agent is introduced into the starvation zone. The method includes: plasticizing and melting a thermoplastic resin into a molten resin in the plasticization zone; introducing a pressurized fluid containing the physical foaming agent having a fixed pressure into the starvation zone; allowing the molten resin to be in the starved state in the starvation zone; bringing the molten resin in the starved state into contact with the pressurized fluid having the fixed pressure in the starvation zone; and molding the molten resin into the foam-molded product. At least one pressure boosting part is provided in the starvation zone.

A method for producing a foam-molded product uses a producing apparatus including a plasticizing cylinder. The plasticizing cylinder has a plasticization zone, a starvation zone, and an introducing port which is formed in the plasticizing cylinder and via which a physical foaming agent is introduced into the starvation zone. The method includes: plasticizing and melting a thermoplastic resin into a molten resin in the plasticization zone; introducing a pressurized fluid containing the physical foaming agent having a fixed pressure into the starvation zone; allowing the molten resin to be in the starved state in the starvation zone; bringing the molten resin in the starved state into contact with the pressurized fluid having the fixed pressure in the starvation zone; and molding the molten resin into the foam-molded product. At least one pressure boosting part is provided in the starvation zone.

A plasticizer includes a drive motor, a flat screw that has a groove forming surface where a groove is formed and is rotated by the drive motor, a barrel which has a groove facing surface that faces the groove forming surface and in which a communication hole is formed, and a heater that heats resin pellets supplied to the space between the flat screw and the barrel, and at least one of the flat screw and the barrel is at least partially formed of a transparent member, and the resin pellets between the flat screw and the barrel is visible through the transparent member.

A plasticizer includes a drive motor, a flat screw that has a groove forming surface where a groove is formed and is rotated by the drive motor, a barrel which has a groove facing surface that faces the groove forming surface and in which a communication hole is formed, and a heater that heats resin pellets supplied to the space between the flat screw and the barrel, and at least one of the flat screw and the barrel is at least partially formed of a transparent member, and the resin pellets between the flat screw and the barrel is visible through the transparent member.