Liquid ejection head and liquid ejection apparatus

A liquid ejection head for ejecting a liquid while being scanned in a main scanning direction, comprising:

• an ejection element configured to generate a pressure for ejecting the liquid in a pressure chamber;
• a supply channel through which the liquid is supplied to the pressure chamber;
• a collection channel connected to the supply channel through the pressure chamber and through which the liquid is collected from the pressure chamber;
• a circulation pump capable of supplying the liquid from the supply channel into the pressure chamber, and collecting the liquid in the pressure chamber through the collection channel and sending the liquid to the supply channel;
• a pressure adjustment unit disposed between an outlet channel of the circulation pump and the supply channel and configured to adjust a pressure in the supply channel;
• and
• a bypass channel through which the pressure adjustment unit and the collection channel communicate with each other, wherein
• the pressure adjustment unit is configured such that pressures with different signs relative to a pressure at rest are generated in response to a forward scan and a backward scan in the main scanning direction.

A liquid ejection apparatus comprising:

• an ink tank;
• and
• a pump configured to supply a liquid from the ink tank to a liquid ejection head, wherein
• the liquid ejection head is a liquid ejection head for ejecting the liquid while being scanned in a main scanning direction, and includes:
• an ejection element configured to generate a pressure for ejecting the liquid in a pressure chamber;
• a supply channel through which the liquid is supplied to the pressure chamber;
• a collection channel connected to the supply channel through the pressure chamber and through which the liquid is collected from the pressure chamber;
• a circulation pump capable of supplying the liquid from the supply channel into the pressure chamber, and collecting the liquid in the pressure chamber through the collection channel and sending the liquid to the supply channel;
• a first pressure adjustment unit disposed between an outlet channel of the circulation pump and the supply channel and configured to adjust a pressure in the supply channel;
• a second pressure adjustment unit disposed between an inlet channel of the circulation pump and the collection channel and configured to adjust a pressure in the collection channel;
• and
• a bypass channel through which the first pressure adjustment unit and the second pressure adjustment unit communicate with each other, and
• at least one of the first pressure adjustment unit or the second pressure adjustment unit is configured such that pressures with different signs relative to a pressure at rest are generated in response to a forward scan and a backward scan in the main scanning direction.