Liquid ejection head and liquid ejection apparatus

A liquid ejection apparatus comprising:

• a liquid ejection head including a print element substrate, the print element substrate having an ejection port surface in which a plurality of ejection ports is arranged and a plurality of temperature control units configured to control a temperature of the ejection port surface;
• and
• a moving unit configured to relatively move the liquid ejection head and a medium onto which a liquid is ejected,
• wherein the liquid is ejected from the plurality of ejection ports onto the medium relatively moved,
• wherein the ejection port surface includes a region on a downstream side of the ejection port surface in a direction in which the medium is relatively moved when the medium is viewed from the liquid ejection head, and includes a region on an upstream side of the ejection port surface in the relative moving direction, and
• wherein each of the plurality of temperature control units includes a temperature sensor configured to detect a value of the temperature of each of the downstream side region and the upstream side region, and includes a temperature control heater configured to heat each of the downstream side region and the upstream side region, and
• wherein each the plurality of temperature control units is configured to control the temperature of the ejection port surface by activating each of the temperature control heaters based on the detected value of the downstream side region and the upstream side region by each of the temperature sensors so that a temperature of the downstream side region becomes higher than a temperature of the upstream side region.

A liquid ejection apparatus comprising:

• a plurality of liquid ejection heads each of which having a print element substrate includes an ejection port surface in which a plurality of liquid ejection ports are arranged, and a temperature control unit configured to control a temperature of the ejection port surface, and each liquid ejection port of the plurality of liquid ejection ports is configured to eject a liquid onto a moving medium;
• wherein the plurality of liquid ejection heads are arranged in parallel from an upstream side to a downstream side in a moving direction in which the moving medium is moved,
• wherein each of the plurality of temperature control units includes a temperature sensor configured to detect a value of the temperature of each of the downstream side and the upstream side, and includes a temperature control heater configured to heat each of the downstream side and upstream side, and
• wherein each of the plurality of temperature control units controls the temperature of an ejection port surface of a liquid ejection head so as to raise the temperature of the ejection port surface of the liquid ejection head toward the downstream side along the moving direction by activating each of the temperature control heaters based on the detected value of the downstream side and the upstream side by each of the temperature sensors.