Drive circuit unit, head unit, and liquid discharge apparatus

A head unit comprising:

• a head including a discharge section discharging, based on a drive signal, a liquid from a nozzle in a first direction;
• and
• a drive circuit unit driving the head, the drive circuit unit including
• a power supply board extending in a second direction opposite to the first direction and B-to-B-coupled to the head,
• a drive circuit generating the drive signal and mounted on a first surface of the power supply board such that the drive circuit is positioned on a side in a third direction relative to the power supply board, the third direction intersecting the first direction and the second direction, and
• a cooling mechanism cooling the drive circuit, the cooling mechanism including
• an air guide portion guiding an airflow created by a fan and covering the drive circuit on the first surface, the air guide portion being positioned on the side in the third direction relative to the power supply board,
• a straightening plate that straightens, toward the second direction, an airflow flowing in a direction intersecting the first direction, or that straightens, toward the direction intersecting the first direction, an airflow flowing in the first direction, the straightening plate being disposed on a side in the first direction relative to the drive circuit, and
• an intake port for supplying air flowing in an order of the straightening plate and the air guide portion, the intake port opening in the third direction and being formed by at least an end portion on a side in the third direction of the straightening plate and an end portion on a side in the first direction of the air guide portion.

A liquid discharge apparatus comprising:

• a transport unit transporting a medium;
• a head including a discharge section discharging, based on a drive signal, a liquid from a nozzle in a first direction;
• and
• a drive circuit unit driving the head, the drive circuit unit including
• a power supply board extending in a second direction opposite to the first direction and B-to-B-coupled to the head,
• a drive circuit generating the drive signal and mounted on a first surface of the power supply board such that the drive circuit is positioned on a side in a third direction relative to the power supply board, the third direction intersecting the first direction and the second direction, and
• a cooling mechanism cooling the drive circuit, the cooling mechanism including
• an air guide portion guiding an airflow created by a fan and covering the drive circuit on the first surface, the air guide portion being positioned on the side in the third direction relative to the power supply board,
• a straightening plate that straightens, toward the second direction, an airflow flowing in a direction intersecting the first direction, or that straightens, toward the direction intersecting the first direction, an airflow flowing in the first direction, the straightening plate being disposed on a side in the first direction relative to the drive circuit, and
• an intake port for supplying air flowing in an order of the straightening plate and the air guide portion, the intake port opening in the third direction and being formed by at least an end portion on a side in the third direction of the straightening plate and an end portion on a side in the first direction of the air guide portion.