This invention relates to an apparatus for forming a gripping tab on a tape for tearing a packing film, and more particularly, to such an apparatus including a device for coloring the tab or printing a colored pattern thereon to facilitate its identification.
A package of cigarettes etc. is usually wrapped in a cellophane or transparent film of a synthetic resin such as polypropylene. This wrapping film has a tab which can be gripped to pull a tape for tearing the film when the package is opened. The tearing tape is a transparent or colored tape of the same material as that from which the wrapping film is formed. The tape is attached to the inside of the wrapping film. One end of the tape slightly projects from a sealed joint on the film and defines the tab.
A known apparatus for forming such a tab usually comprises a device for bonding a tearing tape to an elongate wrapping film, and a cutter having a U-shaped cutting edge aligned with the tape for cutting it to a predetermined length having a U-shaped cut end defining a tab.
A device for coloring the tab is usually located separately from the tab forming apparatus. The tearing tape bonded to the film is colored at predetermined intervals and each colored portion thereof defines a tab. The coloring device is movable in the direction in which the film is fed, so that those portions of the tape which are to be colored may be altered. This prior art is disclosed in Japanese Utility Model Application laid open to the public under No. 38075/1981.
The tab formed by the conventional apparatus is, however, not easy to locate quickly, since the package on which it is provided carries a confusing continuous decorative pattern when the colors used therein are of a similar tone providing less contrast. This is particularly the case when the tab is held in intimate contact with the wrapping film. In this case, it is even likely that the tab may not serve for the purpose for which it is intended.
The coloring device disclosed in the Japanese Application hereinabove referred to is not intended for coloring a tab simultaneously when it is formed. It, therefore, follows that all the tabs cannot always be formed on the colored portions of the tape. Although the device is adjustable to alter those portions of the tape which are to be colored, this adjustment calls for extra work.