Liquid ejection head and liquid ejection apparatus

A liquid ejection apparatus comprising:

• a liquid ejection head including
• a liquid ejection unit configured to eject a liquid,
• a housing including a first channel for supplying the liquid to the liquid ejection unit and a second channel for collecting the liquid from the liquid ejection unit, and
• a liquid circulation unit including
• a supply port for supplying the liquid to the first channel,
• a collection port for collecting the liquid from the second channel,
• a pump configured to supply the liquid collected from the collection port to the supply port, and
• a third channel connecting the supply port and the collection port via the pump,
• the housing including a concave portion including a bottom surface and a side wall connected to the bottom surface, wherein
• the liquid circulation unit is disposed in the concave portion,
• a maximum volume of liquid containable in the concave portion in a use state of the liquid ejection head is larger than a volume of liquid containable in an entirety of the third channel of the liquid circulation unit;
• an ink tank provided outside the liquid ejection head;
• and
• a pump provided outside the liquid ejection head and configured to supply the liquid from the ink tank to the liquid ejection head.