This invention relates to apparatus used for applying labels to containers. The invention has a particular, although not exclusive, application in connection with machinery encompassing roll-fed labelling apparatus.
Roll-fed labellers commonly comprise means for supplying labels to a vacuum drum which, in turn, offers the labels to containers housed on an adjacent rotating turret. The labels, which initially are in the form of a continuous web, are fed through a series of rollers including, for example, a standard cutter and pinch roller, which cuts the web at appropriate lengths in order to provide separate labels. The labels are held to the vacuum drum by a vacuum means before each are released to a respective adjacent container upon which they are intended to be applied.
The containers may be of any type, and are generally those used for containing food or beverages. The containers are mounted in chucks attached to the turret and are adapted to rotate about an axis parallel to the turret axis, about which the turret itself rotates.
In the past it has been known to attach the labels to the containers by various methods. Such methods include the use of adhesives or glues, hot melt techniques, water adhesion and the like. However, a disadvantage of these known methods of securing labels to their respective containers is that their use frequently causes damage or marking to the containers. This obviously has detrimental implications when it is sought to recycle the containers. A similar disadvantage results when removal of the label from the container, which is required during recycling, causes similar marking or damage of the containers.
It is therefore an object of the invention to provide a means of attaching labels to containers, particularly in connection with roll-fed labelling apparatus wherein the container is not potentially marked or damaged by the attachment method. The invention seeks to accomplish this object by causing the label to form a sleeve which snugly circumnavigates the containers; having the leading and trailing edge of the label jointed to each other, as opposed to the container.
Document FR-A-2589431 discloses a method and apparatus for applying a plastic label to a receptacle. The labels are made of a pre-glued material and may take the form of a label web or a series of individual labels. The adhesive applied is thermally activated and is applied to the edges of the inner surface of the labels. The labels are then passed between a guide drum and a heat source which activates the adhesive prior to the label being attached to the receptacle. In this way, the leading edge of the label is glued to the receptacle and the trailing edge overlaps and is fixed to the leading edge via the adhesive printed thereon.
Document EP-A-0437353 discloses a method and apparatus for applying a label to a container. A label material is employed which can be softened by heat so as to create a weld joint between the trailing edge and the leading edge of the label. Preferably, the label is first applied to the container by affixing the leading edge of the label to the container using a hot melt glue, applied using a glue applicator. The label is then passed around the container and a joint is formed by applying heat to the overlapping joint between the trailing edge and the leading edge of the label.
Document US-A-4694633 relates to apparatus for applying a heat-shrinkable film to a receptacle. The leading edge of the film is held in a position closely adjacent to the surface of the receiving article by a spatula device, which incorporates two series of holes. A first series of holes corresponds to the leading edge of the film, by which means the leading edge is secured temporarily utilising a vacuum. This assembly is then rotated such that the film encompasses the circumference of the receptacle. The trailing edge of the film is held in position via a second series of holes on the spatula device, in a manner similar to the leading edge. A heating device is then applied to form the joint between the overlapping trailing and leading edges of the film, whereby the film is held between the spatula and the heating device. In this way, the film is not actually bonded to the surface of the receiving article as is disclosed in FR-A-2589431 or EP-A-0437353.
According to the invention there is provided apparatus for applying a label to a container, the label having a thermally activated adhesive material pre-printed thereon, the apparatus including a heating means adapted to induce thermal bonding of a leading edge of the label to a trailing edge of the label once the label has circumnavigated the container, characterised in that the leading edge of the label is held in contact with the container during said circumnavigation by a non-chemical means excluding any glue or adhesive, or by water.
Preferably, the non-chemical means may be static electricity.
Preferably the heating means comprises electric elements. Alternatively, the heating means may comprise a heat lamp located in juxta-position to the location where said thermal bonding of the leading edge to the trailing edge of the label is required to be effected.
Preferably said apparatus includes a vacuum drum and wherein said electric elements may be housed within said drum.
Alternatively, the heating means may use heat derived from frictional losses in moving parts of the apparatus.
A method of applying a label from a label web to a container, the label web comprising multiple labels, each label having a leading edge and a trailing edge and a thermally activated adhesive material pre-printed thereon, the method comprising:
In order to enable a better understanding of the invention, an example embodiment will now be described with reference to the accompanying drawings:-
Apparatus as may be found in a roll-fed labelling machine comprises a turret 1 which is rotatable about a fixed axis 2. The turret is adapted to support a plurality of containers 3 which, in the embodiment shown, are cylindrical plastic bottles. In use, the turret 1 rotates in a clockwise direction about its axis 2. The bottles or containers 3 are also rotatably mounted by chucks (not shown). The chucks allow the containers 3 to spin in an anti-clockwise direction about their centre axis.
The apparatus also includes a vacuum drum 4 which is adapted to rotate about the axis 5 and comprises suction means for holding labels 6 thereto as it rotates. The vacuum drum is adapted to rotate in a clockwise direction about its axis 5 in use.
A series of rollers 7 supply the labels 6 to the vacuum drum 4. The rollers 7 include a standard cutter and pinch roller 7a which cuts the web of labels 8 into a plurality of individual labels 6. The labels 6 supplied to the drum 4 are inherent with a thermally-activated adhesive material positioned along the leading edge and trailing edge of each respective label 6. This material may be inherent in the label material itself or, alternatively, may be applied as a coating in a print run while the labels are in web form before being applied to the roll-fed labelling apparatus.
In use, the vacuum drum 4 offers a label 6 to a respective container 3. The leading edge of the label 6 is taken up by the container and this may be accomplished using water or any non-chemical means such as static electricity or the like. The label 6 is then encouraged to wrap around said container 3 by the combined rotation of the turret 1, container 3 and vacuum drum 4.
The trailing edge of the label 6 is then secured or otherwise attached to the leading edge of the label through the use of the thermally-activated adhesive material inherent in the label 6. The adhesive material is, in fact, thermally-activated by heating elements 9. In the embodiments shown, the heating elements 9 are housed within the vacuum drum 4. However, the invention is not limited to such an embodiment and the heating elements 9 may, for example, alternatively be in the form of heat lamps or the like.
What is essential to the invention is that a heat source is provided which causes the thermally-activated adhesive material located at least at the leading or trailing edge of the label to be activated. It is realised, however, that the heat of the vacuum drum or other apparatus previously included in roll-fed labelling apparatus may be cleverly employed to provide thermal activation means.
Once the trailing edge of the label 6 is adhered to the leading edge of the label 6 there is provided a sleeve which surrounds the surface of the container. The effect of this is that the bottle or container 3 does not itself receive any glue, adhesive or hot melt directly on its surface of necessity. This will depend, of course, on the means used of causing the label to circumnavigate the container prior to the leading and trailing edge of the label 6 being adhered together. It is realised in the invention that it is advantageous, when it is desired to recycle the container and remove the label, to avoid using an adhesion means which contacts both the label and container as this can lead to marking or damage of the container itself.
The invention described hereinbefore provides a means of applying a label to a container such that the label is in the form of a rolled-on sleeve with minimal or no bonding required between the bottle and the label. This has the advantage of allowing the label to be cut from the bottle with the bottle thereafter being recycled in an undamaged state and, secondly, eliminating or reducing the extent of glue consumables or application equipment being required. This latter aspect of course reduces the capital and running costs of the apparatus required to perform this process of production.