Liquid discharge head substrate, liquid discharge head, liquid discharge apparatus, and method of controlling liquid discharge head

A liquid discharge head comprising:

• liquid discharge head substrate including:
• a discharge opening through which a liquid is discharged;
• a base that includes a surface in which a heat generating element that generates heat to discharge the liquid through the discharge opening is provided;
• a first electrode that covers the heat generating element;
• a flow passage through which the liquid flows from a supply port that supplies the liquid, through the surface of the first electrode, and towards a collection port that collects the liquid;
• a second electrode provided inside the flow passage, the second electrode together with the first electrode forming an electric field in the liquid;
• and
• a pressure chamber including the heat generating element therein,
• wherein the second electrode is provided downstream of the first electrode in a flow direction of the liquid flowing towards the collection port from the supply port,
• wherein the liquid inside the pressure chamber is circulated external to the pressure chamber.

A liquid discharge apparatus comprising:

• a liquid discharge head that includes a liquid discharge head substrate;
• the liquid discharge head substrate including:
• a discharge opening through which a liquid is discharged;
• a base that includes a surface in which a heat generating element that generates heat to discharge the liquid through the discharge opening is provided;
• a first electrode that covers the heat generating element;
• a flow passage through which the liquid flows from a supply port that supplies the liquid, through the surface of the first electrode, and towards a collection port that collects the liquid;
• and
• a second electrode provided inside the flow passage, the second electrode together with the first electrode forming an electric field in the liquid,
• wherein the second electrode is provided downstream of the first electrode in a flow direction of the liquid flowing towards the collection port from the supply port, and
• a voltage applying member that applies a voltage between the first electrode and the second electrode.