Compression controller of injection molding machine

A compression controller of an injection molding machine, which outputs a movement command for compressing a resin in a mold to a compression member of the injection molding machine for each predetermined sampling period, based on a preset compression completion position and a set speed, the compression controller comprising:

• compression operation start condition setting means for setting a compression operation start condition of the compression member;
• establishment determination means for determining whether or not the compression operation start condition set by the compression operation start condition setting means is established during a time interval between successive sampling times;
• and
• movement amount calculation means for obtaining, as a calculated movement amount, the amount of movement of the compression member during a time interval between the point in time when the compression operation start condition is established and a sampling time immediately thereafter when it is determined that the compression operation start condition is established during the time interval between the successive sampling times,
• wherein the movement command for the compression member at the sampling time immediately before the point in time when the compression operation start condition is established is output so that the amount of movement is equal to the calculated movement amount obtained by the movement amount calculation means.