Medium stacking device, printing system, and control method of medium stacking device

A control method of a medium stacking device including

• a stacking platform that is configured to have stacked thereon a medium on which an image is printed by ejecting liquid, and
• a movable fence that moves between a restriction position that restricts an edge portion of the medium that was discharged toward the stacking platform, and a retreat position retreated from the restriction position,
• the control method of the medium stacking device comprising:
• confirming whether or not there is a placement defect of the medium being stacked on the stacking platform;
• determining a movement amount from the restriction position to the retreat position based on medium information of the medium and printing information of the image, when the placement defect of the medium is detected;
• and
• moving the movable fence from the restriction position to the retreat position, and returning the movable fence to the restriction position, based on the determined movement amount.