Cooling device of 3D printer

The invention discloses a cooling device of a 3D printer. The device comprises an annular member; and the annular member includes an annular upper part and an annular lower part. A hollow annular cavity is arranged in the annular upper part; annular side wall of the annular upper part is symmetrically distributed with a plurality of upper air inlets; the lower end of the annular upper part is provided with a plurality of annular upper air outlets; and a plurality of the annular gas paths in inverted trapezoid are arranged in the annular upper part. The upper end of the annular lower part is provided with a plurality of lower air inlets; each lower air inlet aligns with one upper air outlet, so that the annular cavity is in gas communication with a plurality of annular gas paths. The device also comprises an air pump. The annular member surrounds the outer side of an extrusion nozzle. The annular cavity in the invention plays a role of buffering to reduce vibration of gas jet; and the inside of the annular low