Recording element board and liquid discharge head

A recording element board, comprising:

• a discharge orifice configured to discharge liquid;
• a recording element configured to generate thermal energy to cause bubbling of the liquid, the recording element being disposed facing the discharge orifice;
• a pressure chamber having the recording element within;
• a liquid discharge channel communicating with the discharge orifice and the pressure chamber;
• a channel communicating with the pressure chamber;
• a discharge orifice forming member including the discharge orifice and the liquid discharge channel;
• and
• a substrate on which the recording element is formed,
• wherein the bubble generated within the pressure chamber by the driving of the recording element enters inside the liquid discharge channel after the bubble comes into contact with a surface of the discharge orifice forming member closer to the recording element being disposed, and subsequently, the bubble communicates with the atmosphere,
• wherein the flow of the bubble that has entered inside the liquid discharge channel becomes a flow following the wall surface of the liquid discharge channel, and
• wherein a square shape, circumscribing an outline of a discharge orifice projection region where the discharge orifice has been projected to the substrate in a direction perpendicular to the substrate, contains a heat-generating region projection region where a heat-generating region of the recording element has been projected on the substrate.

A liquid discharge head, comprising:

• a discharge orifice forming member including a discharge orifice configured to discharge liquid;
• a pressure chamber communicating with the discharge orifice;
• a recording element configured to generate thermal energy to cause bubbling of the liquid, the recording element being disposed in the pressure chamber facing the discharge orifice;
• a channel communicating with the pressure chamber;
• and
• a substrate on which the recording element is formed,
• wherein the height of the channel in a direction perpendicular to the substrate is 7 μm or less,
• wherein a bubble generated inside the pressure chamber by driving of the recording element communicates with the atmosphere after the bubble comes into contact with a surface of the discharge orifice forming member closer to the recording element being disposed, and
• wherein a square shape, circumscribing an outline of a discharge orifice projection region where the discharge orifice has been projected to the substrate in a direction perpendicular to the substrate, contains completely therein a heat-generating region projection region where a heat-generating region of the recording element has been projected on the substrate.