Tear line forming mechanism for pop-up tissue paper package film

A tear line forming mechanism for pop-up tissue paper package film, comprising:

• a carrier rack;
• a driving device, comprising:
• a driving motor, which is mounted on the carrier rack,
• a driving gear, which is coupled to the driving motor and is driven by the driving motor to rotate, and
• a driving rack, which is mounted to the shifting mechanism to extends in a shifting direction and mates the driving gear;
• a rail mechanism, which is mounted on the carrier rack to extend in the shifting direction;
• a shifting mechanism, which is mounted to the driving rack so that the driving motor drives, via the driving gear and the driving rack, the shifting mechanism to move along the rail mechanism in the shifting direction between a first extreme position and a second extreme position;
• a pair of couplers, which are mounted to the shifting mechanism to be movable in unison with the shifting mechanism in the shifting direction between the first extreme position and the second extreme position, the couplers comprising therein bearing elements;
• a rotary cutter holder, which is rotatably coupled to the pair of couplers through the bearing elements of the pair of couplers and is set between the pair of couplers, the rotary cutter holder being movable in unison with the couplers in the shifting direction between the first extreme position and the second extreme position;
• at least one cutter slot, which is formed in a predetermined location in the rotary cutter holder to receive and hold at least one cutter;
• a cutter holder gear, which is coupled to one end of the rotary cutter holder;
• and
• a rack, which is mounted on the carrier rack to extend in the shifting direction and mate the cutter holder gear;
• wherein when the rotary cutter holder is movable with the couplers in the shifting direction between the first extreme position and the second extreme position, the cutter holder gear is caused by being in mating engagement with the rack to rotate in a rotation direction between a first rotation dead point and a second rotation dead point.