Fastener painting system and method of painting fastener

A fastener painting system for painting a head of a fastener, the fastener painting system comprising:

• a cup for covering the head of the fastener by contacting an edge of the cup with a surface of an object, the cup having a cavity for being filled up with paint;
• a supply system configured to store the paint and supply the paint into the cavity of the cup, the supply system having a syringe;
• a liquid discharging system configured to discharge surplus paint in the cavity out of the cup, the liquid discharging system having a vacuum pump or an ejector;
• and
• a moving mechanism configured to change a position of the cup relative to the object, the moving mechanism having an articulated robot or at least one drive shaft;
• wherein the cup has:
• a supply port for supplying the paint into the cavity;
• a vent for discharging air in the cavity out;
• and
• a liquid discharging port for discharging the surplus paint out of the cavity.