Liquid supply unit and liquid injection device

A liquid supply unit applied to a liquid injection device in which a liquid storage container for storing predetermined liquid is arranged in an upper part, a liquid injection head for injecting the liquid is arranged in a lower part, and the liquid is supplied from the liquid storage container to the liquid injection head, utilizing a water head difference, comprising:

• a first chamber communicating with the liquid storage container, a first pressure obtained by adding a pressure by the water head difference to an atmospheric pressure being set in the first chamber;
• a second chamber arranged downstream of the first chamber in a liquid supply direction and communicating with the liquid injection head, a second pressure decompressed from the first pressure being set in the second chamber;
• a first wall portion including a communication opening allowing communication between the first chamber and the second chamber;
• an opening/closing member arranged in the communication opening, a posture of the opening/closing member being changed between a closing posture for closing the communication opening and an opening posture for opening the communication opening;
• a second wall portion defining the second chamber and including an opening allowing the second chamber to communicate with atmosphere;
• and
• a lever member configured to change a posture thereof between a sealing posture for sealing the opening of the second wall and an opening posture for opening the opening of the second wall;
• wherein the lever member:
• allows the opening/closing member to be set to the closing posture while being set in the sealing posture;
• and
• changes the posture of the opening/closing member from the closing posture to the opening posture while being set in the opening posture.