Patent ID: 7644744

Claim:
A lid sealing machine comprising: a housing including a seat, a casing attached to said housing, a sealing device disposed in said casing, a container holder for supporting containers to be sealed, said container holder being slidably attached to said housing and movable relative to said casing for moving the containers into and out of said casing, and a supply reel, a take up reel and at least one roller rotatably attached onto said housing for supporting a film material and for transmitting the film material from said supply reel around said at least one roller and to said take up reel, and for moving the film material between said sealing device and said container holder, and for allowing the film material to be forced to seal the containers by said sealing device, and said at least one roller being rotatably attached onto said seat of said housing, a photo detector attached to said seat of said housing, said photo detector including a groove formed therein, a rotary member secured to said at least one roller and rotated in concert with said at least one roller for acting with said photo detector, said rotary member including an outer peripheral portion movable into and through said groove of said photo detector, said rotary member including a plurality of slots formed in said outer peripheral portion of said rotary member to form a plurality of blades, said slots and said blades being alternatively and uniformly formed in said outer peripheral portion of said rotary member, and said outer peripheral portion of said rotary member being movable through said groove of said photo detector for detecting a rotating movement of said at least one roller and a movement of the film material relative to said housing.