Active energy emission device

An active energy irradiation device comprising:

• a plurality of active energy irradiation units arranged at least along a predetermined direction;
• a housing that houses the active energy irradiation units;
• an exhaust unit that is provided in the housing, and that discharges air to an outside of the housing;
• an inert gas suction unit that suctions an inert gas from the outside of the housing, the inert gas suction unit including a suction port that allows the inert gas to flow from the suction port into the housing;
• an air-cooled heatsink housed inside the housing and thermally connected to the active energy irradiation units;
• an air flow path including a flow path from an intake unit to the exhaust unit, the air flow path allowing the air to flow through;
• and
• an inert gas flow path including a flow path from the inert gas suction unit to the exhaust unit, the inert gas flow path allowing the inert gas to flow through,
• wherein the air flow path and the inert gas flow path are provided inside the housing,
• the air flow path and the inert gas flow path merge with each other,
• the air flow path and the inert gas flow path pass through the heatsink, and
• the exhaust unit exhausts the inert gas together with the air.