Roll changing air knife capable of reducing waste film amount in film rolling processing

The invention discloses a roll changing air knife capable of reducing waste film amount in film rolling processing. The roll changing air knife comprises a support, and a first rolling roller and a second rolling roller are arranged on a rotating disc of the support; an air blowing mechanism is arranged in a mounting plate on the support, a screw rod of the air blowing mechanism is rotationally arranged in a groove of the mounting plate, the screw rod penetrates through sliding blocks and is in threaded connection with the sliding blocks, the sliding blocks move up and down in the groove of the mounting plate, and an air blowing pipe is arranged between one group of sliding blocks; the two sets of supports are arranged side by side, each set of support is rotationally provided with a rotary disc, and the first winding roller and the second winding roller are arranged in the diameter direction of the rotary disc. Compared with the prior art, a good action distance is kept between the air blowing pipe and the w