Liquid supply system, cartridge, and liquid ejection apparatus

A cartridge capable of being mounted on a liquid reservoir tank communicating with a liquid ejection head to eject a liquid, comprising:

• a liquid reservoir chamber which reserves the liquid to be supplied to the liquid reservoir tank;
• a liquid supply portion configured to communicate fluidly with a first connection portion included in the liquid reservoir tank;
• and
• a second air communication portion configured to be liquid-tightly connected to a second connection portion included in the liquid reservoir tank and located above the first connection portion for connected air communication with a first air communication portion included in the liquid reservoir tank,
• wherein the second connection portion is located below a liquid surface of the liquid reserved in the cartridge at a time when the cartridge in an initial state is mounted on the liquid reservoir tank, a liquid surface of the liquid reserved in the liquid reservoir chamber is located above the second air communication portion.

A liquid ejection apparatus comprising:

• a liquid ejection head to eject a liquid;
• a liquid reservoir tank communicating with the liquid ejection head;
• and
• a cartridge to reserve the liquid to be supplied to the liquid reservoir tank and is capable of being mounted on the liquid reservoir tank, wherein
• the liquid reservoir tank includes:
• a first air communication portion for air-communication of an inside and an outside of the liquid reservoir tank;
• a first connection portion configured to connect the cartridge and the liquid reservoir tank into liquid communication in a state where the cartridge is mounted on the liquid reservoir tank, and
• a second connection portion configured to be located above the first connection portion, liquid-tightly connected with the cartridge for connect the cartridge and the first air communication portion into air communication, in the state where the cartridge is mounted on the liquid reservoir tank,
• wherein the second connection portion is located below a liquid surface of the liquid reserved in the cartridge at a time when the cartridge in an initial state is mounted on the liquid reservoir tank, the second connection portion is located below a liquid surface of the liquid reserved in the cartridge.