Apparatus for attaching a shrinkable label onto a product and method for attaching a shrinkable label onto a product - Patents.com

Abstract

An apparatus and method for attaching a shrinkable label (10) to a product (12) are disclosed. The apparatus for attaching a shrinkable label (10) to a product (12) placed on a conveyor (14) by shining light onto the shrinkable label (10) includes two sets of light emitters (16) positioned opposite each other on either side of the conveyor (14) along a defined length of the conveyor (14) to define an illuminated volume through which the conveyor (14) passes. The light emitters (16) are configured to emit directional beams of light (18) in different directions (20a-20d) within the illuminated volume. In a plan view of the apparatus, the directions (20a-20d) of the beams of light (18) intersect a central longitudinal axis (22) of the conveyor (14). The directions (20a to 20d) of the light beams (18) emitted from the light emitters (16) on the same side of the conveyor (14) and the intersections (24a to 24d) with the longitudinal central axis (22) of the conveyor (14) are different from one another.

Description

[Technical field]

[0001] The present invention relates to an apparatus for applying a shrinkable label onto a product and a method for applying a shrinkable label onto a product. [Background technology]

[0002] Apparatus for attaching shrinkable labels, such as shrink sleeve foils, onto products, such as containers (food containers, bottles, jars, bowls, holders, etc.), is well known in the art. These shrink sleeve foils are made of heat shrinkable material, and when their temperature is increased, they are induced to shrink, thereby being firmly attached to the product. A UV light source can be used to increase the temperature of the shrink sleeve foil, thereby activating the shrinkage of the foils, including the heat shrinkable material.

[0003] WO 2017 / 213506 A1 discloses an apparatus for attaching a sleeve-like label, comprising a heat-shrinkable material and a photothermal conversion material, onto a product. UV light is used to generate heat inside the label, since the label material, or an ink or varnish contained therein, is capable of absorbing the UV light and converting it into thermal energy. As a result, the label material is heated, causing the label to shrink and conform to the shape of the product around which it is placed. To obtain good shrinkage results, a specific UV light peak wavelength of 200-399 nm is used, with at least 90% of the UV light being within a bandwidth of + / - 60 nm of the peak wavelength. By utilizing multiple UV emitters arranged to define an irradiated volume through which the products are transported on a conveyor, a relatively low-cost and / or compact arrangement for fast and reliable attachment of the label to the product can be realized. In order to achieve a uniform distribution of light intensity across the label and improve the uniformity of illumination of the product, in the embodiment shown in Figure 6 of WO 2017 / 213506 A1 the light emitters are oriented to focus their emitted light in the centre of the apparatus, on the products being transported on a conveyor. Summary of the Invention

[0004] It is essential that the sleeve material is exposed to the light beam in such a way that a uniform temperature profile can be achieved, which requires that the light beam emitted by the light emitter impinges on the sleeve surface in a substantially perpendicular direction while the sleeve, which is placed on the product, is transported together with the product through the irradiation volume.

[0005] Starting from the device disclosed in figure 6 of WO 2017 / 213506 A1, the object of the present invention is to provide an apparatus and a method for attaching a sleeve-like shrinkable label onto a product, which achieves a uniform shrink effect of the label on the product. This object is achieved by the subject matter of the independent claims. Advantageous further developments are presented in the dependent claims.

[0006] According to the invention, there is provided an apparatus for attaching a sleeve-shaped shrinkable label onto a product placed on a conveyor by shining light onto the shrinkable label. The apparatus comprises two sets of light emitters arranged opposite each other on either side of the conveyor along a defined length of the conveyor to form an illuminated volume through which the conveyor passes. The light emitters are configured to emit directional light beams in different directions into the illuminated volume, the directions of the light beams intersecting the central longitudinal axis of the conveyor in a plan view of the apparatus. The invention is characterized in that in a plan view of the apparatus, the intersection points of the directions of the light beams emitted by the light emitters on the same side of the conveyor and the central longitudinal axis of the conveyor are different from each other.

[0007] Each of the light emitters in each set of light emitters may include multiple light sources, which are positioned in a pattern including several rows and columns and are configured to emit a directional light beam into an illumination volume through which the products are transported on the conveyor. The multiple light sources per light emitter may extend in a vertical direction relative to the conveyor or to the trajectory of the products placed on the conveyor. In particular, if the conveyor extends horizontally and the trajectory of the products placed on the conveyor is assumed to be horizontal, the multiple light emitters per set of light emitters may extend vertically, i.e., the multiple light sources per set of light emitters may be positioned in a pattern of horizontal rows and vertical columns. Thus, the products can be illuminated in a wide and uniform manner. The arrangement of the two sets of light emitters facing each other on either side of the conveyor encompasses or defines an illumination volume centered between the opposing sets of light emitters through which the conveyor passes and through which the products placed on the conveyor are illuminated.

[0008] The directional light bundle emitted by each light emitter or by each light source of each light emitter into the illumination volume is formed of a plurality of single light beams. Each light bundle has a specific illumination direction, i.e. orientation, and can be a parallel or divergent light bundle. In the case of a parallel light bundle, in the plan view of the device, the light bundle formed of the plurality of light beams has a rectangular form, the illumination direction corresponding to the center line of said rectangle. In the case of a divergent light bundle, in particular a cone-shaped light bundle, in the plan view of the device, the light bundle has substantially the form of a triangle, the illumination direction corresponding to the bisector of the angle of said triangle.

[0009] According to the invention, in the plan view of the device, the directions of the light beams emitted by the light emitters on the same side of the conveyor and the intersections of the central longitudinal axis of the conveyor are different from each other. That is, the intersections of the directions of the light beams emitted by the light emitters on the same side of the conveyor and the central longitudinal axis of the conveyor are offset from each other along the longitudinal direction of the conveyor and therefore along the path along which the products are transported by the conveyor through the irradiation volume. In other words, in the plan view of the device, the light emitters of one set of light emitters are directed to different parts of the conveyor belt and the directions of the light beams are different from each other. With such a configuration, the sleeve-like labels on the products can be uniformly illuminated from all sides while they are transported on the conveyor through the irradiation volume without the need to rotate the products on the conveyor. Due to the specific arrangement of the light emitters and the specific irradiation direction of the light beam, respectively, the light beam of the light beam emitted by the light emitters can impinge on the sleeve surface in a vertical direction at multiple positions over the circumference of the sleeve-like label while the product is transported through the irradiation volume on the conveyor. Therefore, a uniform light irradiation of the sleeve surface can be achieved during the exposure period of the product inside the irradiation volume, resulting in a uniform temperature rise of the label. Thus, a uniform shrinkage effect of the label on the product can be achieved.

[0010] The two sets of light emitters can be arranged symmetrically with respect to the conveyor. In such a preferred embodiment, the central longitudinal axis of the conveyor corresponds to the axis of symmetry of the device. This configuration further contributes to a uniform irradiation and temperature rise of the sleeve-like label during the exposure of the product inside the irradiation volume. However, an asymmetric arrangement of the two sets of light emitters is also conceivable.

[0011] In the plan view of the device, the irradiation volume may have an oval shape, in particular an elliptical shape. In other words, in the plan view of the device, the light emitters may lie on an oval curve, in particular an elliptical curve. It should be noted that this elliptical shape also includes a substantially elliptical shape. With such a configuration, an even more uniform irradiation and temperature rise of the sleeve-like label during the exposure period can be achieved. In particular, the oval shape, in particular the elliptical shape, allows the product to be uniformly irradiated from all sides while being transported through the irradiation volume, improving the temperature distribution of the sleeve-like label over the circumference of the product.

[0012] The two sets of light emitters may include the same number of light emitters, in particular four light emitters.

[0013] The device may comprise a plurality of side reflectors forming the side boundaries of the irradiation volume for reflecting the light emitted by the light emitters into the irradiation volume, the light emitters and the side reflectors being arranged alternately for each set of light emitters. The side reflectors further improve the uniform irradiation of the product inside the irradiation volume by reflecting the light emitted by the light emitters. In particular, the side reflectors help to ensure that the product is uniformly irradiated from all sides of the product, so that the temperature of the sleeve-like label along its periphery can be uniformly increased during the exposure period. Therefore, good shrinkage results can be achieved.

[0014] The device may further comprise a top reflector and / or a bottom reflector, which are arranged to respectively constitute the top and / or bottom boundaries of the irradiation volume for reflecting the light emitted by the light emitter into the irradiation volume. Products, in particular bottle-like containers, often have a curved top part and a curved bottom part. By using the top reflector and the bottom reflector, the light emitted by the light emitter is reflected onto the curved top part and the curved bottom part of the product, respectively, to obtain a uniform temperature profile along the vertical axis of the sleeve material. In other words, the high temperature required to reliably shrink the sleeve-like label onto the curved part of the product, and therefore a good shrinking result, can be achieved.

[0015] The reflector can be flat, and in the preferred embodiment a flat reflector is used due to its ready availability and low cost, although curved reflectors are also envisaged.

[0016] The reflector can be made of any light-reflecting material. For example, the reflector can be made of metal, in particular aluminum sheet metal or aluminum foil. The reflector can also be made of steel, in particular stainless steel.

[0017] The apparatus may include a controller configured to control the light emitters to emit a light flux to illuminate a shrinkable label disposed on a product within the illumination volume. As described below, the controller may be configured to selectively control the light emitters depending on the type of light emitter to continuously or discontinuously illuminate the shrinkable label while the product is conveyed through the illumination volume. When the light emitters each include multiple light sources, the above-mentioned selective control of the light emitters may include selective control of the light emitters as well as selective control of the individual light sources of each light emitter.

[0018] By selectively controlling the light emitters, it is possible to sequentially activate the light emitters according to the temporal position of the product moving through the irradiation volume in such a way that the light beam of the sequentially activated light emitters follows the product moving through the irradiation volume. In other words, sequentially activating only those light emitters whose emitted light beams match the temporal position of the product moving through the irradiation volume according to the temporal position of the product moving through the irradiation volume allows reducing the heat emission into the irradiation volume by not activating light emitters whose light beams do not match the temporal position of the product moving through the irradiation volume.

[0019] The light emitter may be a UV light emitter, in particular an LED. In a preferred embodiment, the light emitter is a UV LED. By using a UV LED, heat is not applied from the outside, but is generated inside the sleeve-like label, since the label material, or the ink or varnish contained in the label material, is able to absorb the UV light and convert it into heat energy. When using a UV light emitter as the light emitter, both continuous and discontinuous irradiation of the shrinkable label is possible.

[0020] The light emitter may be a mercury or halogen lamp. Such lamps emit polychromatic light rather than monochromatic light. Moreover, such lamps have higher efficiency and higher robustness compared to LED light emitters. The output power of mercury and halogen lamps is very high and they are less expensive compared to LED light emitters. However, when using mercury or halogen lamps, only continuous illumination of the shrinkable label is possible while the product is being conveyed through the illumination volume.

[0021] As a further alternative, the light emitter may be an IR lamp, which is common as a high power lamp and is less expensive compared to UV light emitters.

[0022] The conveyor may be part of the device. In this case, the length of the conveyor, along with its trajectory inside the device, may be equal to or (slightly) greater than the length of the device. In this way, a device with a conveyor can be easily integrated into an existing production line by interposing the conveyor of the device in the normal conveyor of the production line. Furthermore, since the length of the conveyor of the device is preferably limited to the length of the device, materials and / or coatings with special properties can be used for the conveyor without unduly increasing the costs, as will be described below.

[0023] In particular, the conveyor, or at least the conveyor belt supporting the products, can be made of a material capable of withstanding the high temperatures generated by the light emitters inside the irradiation volume of the device. This can prevent the conveyor or the conveyor belt from being partially melted and damaged. For example, the conveyor can be made of stainless steel. In particular, the conveyor belt can consist of a number of plates arranged successively along the conveyor track and supporting the products moving through the irradiation volume. In this case, it can be sufficient if the conveyor plates are made of a material capable of withstanding the high temperatures generated by the light emitters inside the irradiation volume of the device or are coated with such a material. For example, the conveyor plates are made of steel, in particular stainless steel.

[0024] Furthermore, the conveyor belt may be made of a light-reflecting material or may have a light-reflecting coating. Thus, the light emitted by the light emitters can be reflected by the conveyor onto the curved bottom part of the product, similar to the bottom reflector of the device, further improving the uniformity of the temperature profile along the vertical axis of the sleeve material. In other words, the high temperature required to reliably shrink the sleeve-like label onto the curved bottom part of the product, and therefore a good shrinking result, can be achieved. For example, as mentioned above, the conveyor plate is made of steel, specifically stainless steel.

[0025] A first method of attaching a shrinkable label disposed on a product to the product using an apparatus according to the present invention including a controller includes the steps of transporting the product on a conveyor through an irradiation volume and controlling an illuminator to continuously emit a light beam while the product is transported on the conveyor through the irradiation volume.

[0026] According to the first method of the present invention, the sleeve-shaped label placed on the product begins to be exposed to the light emitted by the light emitter when the product enters the irradiation volume, and the exposure ends when the product placed on the conveyor leaves the irradiation volume. The first method is also called a continuous mode.

[0027] In the first method, the emitters can be controlled to output at 65% relative power. The inventors have found that in continuous mode, 65% relative output power of the UV emitters provides good shrinkage results.

[0028] A second method of attaching a shrinkable label disposed on a product to the product using an apparatus according to the present invention including a UV LED as an illuminant and a controller includes the steps of transporting the product on a conveyor through an irradiation volume and controlling the illuminant to emit a discontinuous light flux while the product is transported on the conveyor through the irradiation volume.

[0029] According to the second method of the present invention, the sleeve-shaped label placed on the product is only temporarily illuminated with the light emitted by the light emitter while the product is transported through the irradiation volume on the conveyor.For example, if the two sets of light emitters each contain four light emitters, the light emitters can be controlled to emit light on the product only while the product is approximately between the two middle light emitters.The second method is also called pulse mode.

[0030] In the second method, the emitter can be controlled to output between 60% and 100% relative power. The inventors have found that in pulsed mode, a relative output power of 60% to 100% of the UV LED emitter provides the best shrink results. [Brief description of the drawings]

[0031] With the aid of the attached figures, preferred embodiments are explained in more detail below. [Figure 1] 1 shows a perspective view of a preferred embodiment apparatus according to the present invention; [Diagram 2] FIG. 2 shows a perspective view of an apparatus according to the present invention showing a top reflector and a bottom reflector. [Diagram 3] 1 shows a plan view of a preferred embodiment device according to the present invention illustrating the directional light flux emitted by the light emitters. [Figure 4] 4 shows a plan view of a preferred embodiment of an apparatus according to the present invention, illustrating the irradiation direction of the light beams of FIG. 3. [Diagram 5] FIG. 2 shows a perspective view of a device having curved side reflectors according to the present invention. [Figure 6] FIG. 6 shows a plan view of the device of FIG. 5. [Figure 7] 1 shows a plan view of an apparatus according to the invention; [Figure 8] 1 shows a label surface being illuminated perpendicularly by a light beam. [Figure 9] 3 shows the bottom portion of the product being illuminated by a light beam. [Figure 10] FIG. 1 shows a front view of the product in the form of a bottle.

[0032] These drawings are not intended to be limiting in any way, and it is envisioned that various embodiments of the invention may be embodied in a variety of other ways, including those not necessarily shown in the drawings. The accompanying drawings, which are incorporated in and form a part of this specification, illustrate several aspects of the invention and, together with the description, serve to explain the principles of the invention. It should be understood, however, that the invention is not limited to the precise arrangements shown. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] The following description of the preferred embodiment of the present invention should not be used to limit the scope of the present invention. Other examples, features, aspects, embodiments, and advantages of the present invention will become apparent to those skilled in the art from the following description, which is, by way of example, one of the best modes contemplated for carrying out the present invention. As will be understood, the present invention is capable of other different and obvious aspects without departing from the present invention in any way. Thus, the drawings and the specification should be regarded as illustrative in nature and not restrictive. Various suitable ways in which the teachings of this specification can be combined will be readily apparent to those skilled in the art in light of the teachings of this specification. Such modifications and variations are intended to be included within the scope of the claims.

[0034] Preferred Embodiments 1, 3 and 4 show diagrams of a preferred embodiment apparatus according to the present invention.

[0035] With reference to Figures 1, 3 and 4, an apparatus 1 for attaching a sleeve-like shrinkable label 10 onto a product 12 in the form of a bottle is shown. In particular, the bottle has a shape as shown in Figure 10. The product 12 is placed on a conveyor 14 that transports the product 12 and the label 10 loosely placed on the product 12 through an irradiation volume defined by two sets of light emitters 16 arranged opposite each other on either side of the conveyor 14. It should be noted that Figure 1 shows only one of the two sets of light emitters 16. The sleeve-like label 10 is made of a heat-shrinkable material, and when its temperature is increased by irradiation of the light emitters 16, it is induced to shrink, thereby being firmly attached to the product 12.

[0036] In a preferred embodiment, the two sets of light emitters 16 are arranged symmetrically with respect to the conveyor 14. As shown in the plan view of the device 1 in FIG. 3, the central longitudinal axis 22 of the conveyor 14 corresponds to the axis of symmetry of the device 1. It should be noted that the three products 12 shown in FIG. 3 depict one and the same product 12 at three different times. The arrangement of the two sets of light emitters 16 facing each other on either side of the conveyor 14 encompasses an illumination volume centered between the opposing sets of light emitters 16 through which the conveyor 14 passes and illuminates the products 12 placed on the conveyor 14 by the light emitters 16. In a preferred embodiment, each set of light emitters 16 includes four light emitters 16.

[0037] As shown in the plan views of the device 1 in Figures 3 and 4, the irradiation volume defined by the arrangement of the two sets of light emitters 16 has a substantially elliptical shape. In other words, in the plan views of the device 1, the light emitters 16 lie on a substantially elliptical curve. With such a configuration, a uniform irradiation and temperature rise of the sleeve-like label 10 during the exposure period can be achieved. In particular, the substantially elliptical shape allows the product 12 to be uniformly irradiated from all sides while being transported through the irradiation volume, thereby improving the temperature distribution of the sleeve-like label 10 around the circumference of the product 12.

[0038] Each of the light emitters 16 includes a number of light sources in the form of UV LEDs, which are positioned in a pattern (not shown in detail in the drawings) and are configured to emit a directional light beam 18 into an irradiation volume through which the products 12 are transported on the conveyor 14. The light sources for each light emitter 16 extend vertically to the conveyor 14 or to the trajectory of the products 12 arranged on the conveyor 14, which passes horizontally through the irradiation volume. Thus, the sleeve-like label 10 on the product 12 can be widely and uniformly irradiated over its entire vertical height. By using UV LEDs, heat is generated inside the sleeve-like label 10, rather than being applied from the outside, since the label material is capable of absorbing UV light and converting it into thermal energy.

[0039] The directional light bundles 18 emitted by each UV LED of each light emitter 16 in the irradiation volume are formed by light beams 32. As shown in FIG. 3, each light bundle 18 has a specific irradiation direction 20a-20d (only the irradiation directions of the light bundles 18 of one set of light emitters 16 are labeled with reference numbers), i.e. orientation. The light bundles 18 are cone-shaped diverging light bundles 18, and in the plan view of FIG. 3, each light bundle 18 has substantially the form of a triangle, the irradiation directions 20a-20d corresponding to the bisectors of the angles of the triangle. It should be noted that for reasons of clarity only, the light bundles 18 shown in the drawing are limited by circular arcs in the respective irradiation directions 20a-20d.

[0040] As shown in Figures 3 and 4, the directions 20a-20d of the light beams 18 emitted by the light emitters 16 on the same side of the conveyor 14 and the intersections 24a-24d with the central longitudinal axis 22 of the conveyor 14 are different from each other. That is, the directions 20a-20d of the light beams 18 emitted by the light emitters 16 on the same side of the conveyor 14 and the intersections 24a-24d with the central longitudinal axis 22 of the conveyor 14 are offset from each other along the longitudinal direction of the conveyor 14 and therefore along the trajectory of the products 12 transported by the conveyor 14 through the irradiation volume. In other words, in the plan view of the device 1 in Figures 3 and 4, the light emitters 16 of one set of light emitters 16 are directed towards different parts of the conveyor belt and the directions 20a-20d of the light beams 18 are different from each other. With such a configuration, the sleeve-like label 10 on the product 12 can be uniformly illuminated from all sides while it is being transported on the conveyor 14 through the irradiation volume, without the need to rotate the product on the conveyor 14. Due to the specific arrangement of the light emitters 16 and the specific irradiation directions 20a-20d of the light bundle 18, respectively, the light beams 32 of the light bundle 18 emitted by the light emitters 16 can impinge on the sleeve surface in a vertical direction at multiple positions over the circumference of the sleeve-like label 10 while the product 12 is being transported on the conveyor 14 through the irradiation volume (see FIG. 8). Therefore, during the exposure period of the product 12 inside the irradiation volume, a uniform light irradiation of the sleeve surface can be achieved, resulting in a uniform temperature rise of the label. Thereby, a uniform shrinkage effect of the label 10 on the product 12 can be achieved.

[0041] As shown in Figures 1, 3 and 4 of the preferred embodiment, the device 1 comprises flat side reflectors 26 made of aluminum sheet metal, forming the side boundaries of the irradiation volume, for reflecting the light emitted by the light emitters 16 into the irradiation volume. The light emitters 16 and the side reflectors 26 are arranged alternately for each set of light emitters 16. The side reflectors 26 further improve the uniform irradiation of the products 12 inside the irradiation volume by reflecting the light emitted by the light emitters 16. In particular, the side reflectors 26 help to ensure that the products 12 are uniformly illuminated from all sides of the products 12 (see Figure 8), thereby allowing the temperature of the sleeve-like label 10 along its circumference to be uniformly increased during the exposure period.

[0042] The device 1 according to the preferred embodiment further comprises a top reflector 28 and a bottom reflector 30 arranged to respectively constitute the top and bottom boundaries of the irradiation volume for reflecting the light emitted by the light emitter 16 into the irradiation volume. Products, in particular bottle-like containers, often have a curved top part and a curved bottom part. As shown in FIG. 9, by using the top reflector 28 and the bottom reflector 30, the light beam 32 of the light bundle 18 emitted by the light emitter 16 is reflected onto the curved top part and the curved bottom part of the product 12 or the label 10, respectively. Thus, a uniform temperature profile along the vertical axis of the sleeve material can be obtained. In other words, the high temperature required for a reliable shrinking of the sleeve-like label 10 onto the curved part of the product 12, and therefore a good shrinking result, can be achieved.

[0043] method In the following, a preferred method for attaching a shrinkable label disposed on a product to the product using the device according to the preferred embodiment is described. This method is also referred to as pulse mode. Although not shown in the drawings, the device 1 comprises a controller configured to control the light emitter 16 to emit a light beam 18 to illuminate the shrinkable label 10 disposed on the product 12 in the irradiation volume.

[0044] According to this method, as shown in FIG. 1, the shrinkable label 10, which is placed on the product 12, is transported through the irradiation volume of the device 1 on a conveyor 14. The light emitters 16 in the form of UV LEDs are controlled to emit a light beam 18 discontinuously while the product 12 is transported through the irradiation volume on the conveyor 14. The sleeve-shaped label 10, which is placed on the product 12, is therefore only briefly illuminated with the light emitted by the light emitters 16 while the product 12 is transported through the irradiation volume on the conveyor 14. In a preferred embodiment, the two sets of light emitters 16 each include four light emitters 16. In the pulse mode, the light emitters 16 are controlled to emit light on the product 12 only while the product 12 is approximately between the two intermediate light emitters 16. In other words, as shown in Fig. 3, the light emitter 16 starts emitting the directional light beam 18 onto the product when the product 12 placed on the conveyor 14 reaches the leftmost position of the three product positions shown, i.e., the intersection point 24a shown in Fig. 4. Furthermore, the light emitter 16 stops emitting the directional light beam 18 onto the product when the product 12 placed on the conveyor 14 reaches the rightmost position of the three product positions shown, i.e., the intersection point 24d shown in Fig. 4.

[0045] Further embodiments In a preferred embodiment, the two sets of light emitters are arranged symmetrically with respect to the conveyor, however, an asymmetric arrangement of the two sets of light emitters is also conceivable.

[0046] In a preferred embodiment, the reflector is flat, however curved reflectors are also envisaged, as shown in Figures 2, 5 and 6.

[0047] In a preferred embodiment, the light emitter is a UV LED. However, the light emitter 16 may also be a mercury lamp or a halogen lamp. Such lamps emit polychromatic light rather than monochromatic light. Furthermore, such lamps have higher efficiency and higher robustness compared to LED light emitters. The output power of mercury and halogen lamps is very high, and they are less expensive compared to LED light emitters.

[0048] As a further alternative, the light emitter may be an IR lamp, which is common as a high power lamp and is less expensive compared to UV light emitters.

[0049] As mentioned above, according to a preferred method, the light emitters are controlled to emit a light flux discontinuously while the product is transported through the irradiation volume on the conveyor. In particular, the light emitters are controlled to emit light on the product only while the product is approximately between two middle light emitters of the four light emitters of each set of light emitters. However, depending on the product's form, the light emitter's irradiation pulse can also start earlier or later and can stop earlier or later.

[0050] Moreover, according to another method, also referred to as a continuous mode, the controller can be configured to control the light emitters to continuously illuminate the shrinkable label while the product is being conveyed through the illumination volume, whereby the sleeve-like label placed on the product begins to be exposed to light emitted by the light emitters when the product enters the illumination volume and ends when the product placed on the conveyor leaves the illumination volume. [Explanation of symbols]

[0051] 1 device 10 Label 12 products 14 Conveyor 16 Luminous Object 18 Luminous flux 20a~20d direction 22 Longitudinal central axis 24a~24d intersection 26 Side reflector 28 Upper reflector 30 bottom reflector 32 Light Beam

Claims

1. 1. An apparatus for attaching a shrinkable label to a product disposed on a conveyor by shining light onto the shrinkable label, the apparatus comprising two sets of light emitters disposed opposite each other on either side of the conveyor along a defined length of the conveyor to define an illuminated volume through which the conveyor passes, the light emitters being configured to emit directional light beams in different directions within the illuminated volume, the directions of the light beams intersecting a central longitudinal axis of the conveyor in a plan view of the apparatus, 11. An apparatus according to claim 10, wherein in a plan view of the apparatus, the directions of the light beams emitted from the light emitters on the same side of the conveyor and the intersections with the central longitudinal axis of the conveyor are different from one another.

2. The apparatus of claim 1 , wherein the two sets of emitters are positioned symmetrically with respect to the conveyor.

3. 3. The device according to claim 1 or 2, wherein in a plan view of the device, the irradiation volume has an oval shape, in particular an elliptical shape.

4. The device according to any one of claims 1 to 3, wherein the two sets of light emitters comprise the same number of light emitters.

5. Further comprising a reflector, 5. The apparatus of claim 1, wherein the reflector comprises a plurality of side reflectors forming lateral boundaries of the irradiation volume for reflecting light emitted by the light emitters into the irradiation volume, the light emitters and the side reflectors being arranged alternately for each set of light emitters.

6. The apparatus of claim 5, wherein the reflector further comprises a top reflector and / or a bottom reflector arranged to respectively form an upper boundary and / or a bottom boundary of the irradiation volume for reflecting light emitted by the light emitter into the irradiation volume.

7. 7. Apparatus according to claim 5 or 6, wherein the reflector is flat.

8. The device according to any one of claims 5 to 7, wherein the reflector is made of aluminium sheet metal or aluminium foil.

9. 9. The apparatus of claim 1, further comprising a controller configured to control the light emitters to emit the light beam to illuminate the shrinkable label disposed on the product within the irradiation volume.

10. The apparatus of claim 9 , wherein the light emitter is a UV light emitter.

11. 10. The apparatus of claim 9, wherein the light emitter is a mercury lamp, a halogen lamp, or an IR lamp.

12. A method of attaching the shrinkable label disposed on the product using the apparatus of claim 10 or 11, comprising the steps of: transporting the product on the conveyor through the irradiation volume; controlling the light emitters to emit the light beam continuously while the products are transported on the conveyor through the illumination volume; A method comprising:

13. The method of claim 12, wherein the light emitters are controlled to output at 65% relative power.

14. A method of attaching the shrinkable label disposed on the product using the apparatus of claim 10, wherein the light emitter is an LED; transporting the product on the conveyor through the irradiation volume; controlling the light emitters to emit the light flux discontinuously while the products are transported on the conveyor through the illumination volume; A method comprising:

15. The method of claim 14, wherein the light emitters are controlled to output between 60% and 100% relative power.

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