Pressure controller for injection molding machine

A pressure controller for an injection molding machine, the pressure controller including an injection screw drive unit for driving an injection screw, an injection pressure detection unit for detecting an injection pressure, a screw movement amount detection unit for detecting an amount of movement of the injection screw, a screw speed control unit for controlling a movement speed of the injection screw in an injection step, an injection dwell switching unit for switching from the injection step to a dwell step, and an injection pressure control unit for controlling the injection pressure in the dwell step after the injection dwell switching, the pressure controller comprising:

• an in-mold pressure estimation unit for estimating a pressure in a mold based on the injection pressure detected with the injection pressure detection unit, and the amount of movement of the screw detected with the screw movement amount detection unit;
• and
• an in-mold pressure control unit for controlling such that the estimated in-mold pressure becomes a set in-mold pressure after the pressure control is performed in the dwell step with the injection pressure control unit.