Self-weight pressure control valve, liquid supply system including the same, and inkjet recording device

A liquid supply system, comprising:

• a liquid supply that stores a liquid;
• a liquid injection head that injects the liquid;
• a liquid supply path including an end in communication with the liquid supply and another end in communication with the liquid injection head;
• a supply pump located on the liquid supply path;
• a pressure control valve located on the liquid supply path;
• a support that supports the pressure control valve such that an axial direction of a valve rod is vertical;
• a damper located on the liquid supply path;
• an ink storage amount detector that detects an amount of the liquid stored in the damper;
• and
• a controller configured or programmed to control the supply pump to be actuated or stopped;
• wherein
• the liquid supply path in the pressure control valve is closed when the supply pump is to be stopped;
• the liquid supply path in the pressure control valve is opened when the supply pump is to be actuated;
• the pressure control valve includes a case main body h an opening in an upper surface thereof;
• and
• a thin film is attached to the upper surface of the case main body and covers the opening.