Conventional cigarette packaging equipment includes machinery for overwrapping cigarette packages with an overwrap made of either a transparent or metallized polymeric film and having a tear tape for tearing open the overwrap. One such machine is a Model 4350 Packager manufactured by G. D. Societa per Azioni of Bologna, Italy and known as the "GD 4350" machine. In this machine, each cigarette package of twenty cigarettes is individually overwrapped with the polymeric film, heat sealed and then placed in stacks of two packs for delivery by an intermittent motion or indexing turret mechanism to a cigarette cartoner apparatus in which five stacks of two packs (ten packs) are inserted into a cigarette carton. During the overwrapping process, the GD 4350 machine is designed to detect various defects in the cigarette packs, such as, for example, crushed packages, missing or wrinkled overwraps, defective side and end flap seals, missing or misplaced tear tapes and the like. Defective packs are rejected in the GD 4350 machine after the packs have been arranged in the two pack stack configuration. The known machine does not discriminate between an acceptable pack and a defective pack in the two pack stack so that both packs are rejected even if only one pack is defective. The result of this arrangement is that approximately 25% of all rejected packs are acceptable.
U.S. Pat. No. 5,101,609 discloses the prior art package rejection mechanism as well as a recent improvement to the package inspection system of a GD 4350 machine in which each two pack stack of cigarettes is removed from the product stream for inspection by video cameras and is then returned to the product stream for conveyance to the cartoner apparatus. Even in the improved inspection system, if only one defective pack is detected in a two pack stack, both packs of the stack are rejected, again resulting in about 25% of the rejected packs being acceptable packs.
It would be desirable therefore from an economic standpoint to provide a mechanism for the GD 4350 machine or any other comparable apparatus in which only the defective pack of a stack of two packs is rejected and in which both packs are rejected only if both are defective. In addition, it is essential that such mechanism be operable to reject packs from the two pack stack at the maximum production speed of the GD 4350 machine which ranges from about 400 up to about 500 packs per minute (ppm).