Automatic positioning device of printing-down machine for environment-friendly printing

The utility model discloses an automatic positioning device of an environment-friendly printing-down machine for printing, and relates to the technical field of printing-down machines, the automatic positioning device comprises a printing-down machine body, the front side of the printing-down machine body is connected with a control panel, the upper part of the printing-down machine body is connected with a set of hinges, the outer sides of the hinges are connected with a cover plate, and the upper part of the printing-down machine body is connected with a positioning mechanism. A dust collecting mechanism penetrates through the top end of the cover plate; the first motor is started to drive the bidirectional screw rod to rotate, then the first ball nut and the second ball nut at the two ends of the bidirectional screw rod are driven to move oppositely, the left positioning frame and the right positioning frame are driven to move at the same time, a screen plate on the inner sides of the left positioning fram