Method and apparatus for marking shrink wrap lid for beverage container

Abstract

A reflective hood system for heat-shrinking a film onto an open-topped container includes a reflective hood having a reflective surface, a radiant energy source, and a reflective shield, wherein the reflective shield is located at or near an opening in the reflective hood, and wherein the reflective shield has at least one optical aperture, an optical aperture including an optical surface having areas of higher and lower reflective capability. The reflective hood assembly may further include a reflective shield having two or more optical apertures.

Description

DESCRIPTION OF THE INVENTION

[0001] 1. Field of the Invention

[0002] This invention pertains to a method for marking a heat shrinking thin film lid for an open-topped container, such as a cup. In particular, this invention pertains to a method for marking a film to create a weak area. Moreover, this invention pertains to a method for marking a film for a cup lid to identify the contents of the cup.

[0003] 2. Background of the Invention

[0004] Presently, in the fast food drink industry, it is typical to serve a drink in a paper, plastic, or other disposable cup topped with a preformed plastic lid. The plastic lid fits relatively tightly over the brim formed at the top of, for example, a paper drink cup, and may include apertures to permit straws or openings to be formed in the lid to allow one to directly drink the contents of the cup without removing the lid. Moreover, the plastic lid may include “bubbles” that can be manually deformed to identify the contents of the cup.

[0005] Unfortunately, there are many problems associated with the use of these plastic lids. For example, the lids are bulky and create problems in storage and in disposal. Still further, the seal formed by the lids is dependent upon the lid being placed on the cup properly, and can leak if not properly

[0006] In order to overcome these problems, various devices and methods have been proposed in which a cover is placed on an open-topped container and then heated to shrink it into sealing engagement with the top of such a container. These prior art devices and methods fail to provide a sufficiently cost efficient, easy, and inexpensive alternative to preformed rigid plastic lids. As a consequence, rigid plastic lids remain in widespread use.

[0007] Some of the main failings of these prior devices are that they are bulky, noisy, unresponsive, and expensive. Heating systems, comprising blowing air over a hot element and then onto a film, require large amounts of unnecessary heat, even when in standby mode, which makes temperature control very difficult. Further, continuous elevated temperatures are expensive to maintain and may be deleterious to the immediate environment.

[0008] An improvement to these prior art systems is found in a device described in U.S. Pat. No. 5,249,410, incorporated herein by reference, which uses heat shrinkable film lids having annular energy absorbent regions formed thereon, preferably by application of an energy absorbent ink such as by printing. In this device for shrinking thin film over a container to form a lid, multiple radiant energy sources are utilized. The primary radiant energy source is located closely adjacent to the lip of the cup and moves peripherally around the lid while a secondary radiant energy source is stationed over the cup. When the primary energy source is activated, energy falling upon the energy absorbent region in the film causes the film to shrink, preferentially in the area around the lip of the cup, while energy from the secondary energy source may serve to tauten up the central portion of the lid. Alternatively, multiple primary radiant energy sources can be located around the periphery of the mouth of the cup. The apparatus disclosed in the '410 patent lacks an efficient method of concentrating and redirecting energy toward the region of the film which is to be shrunk.

[0009] In another arrangement of the above, the radiant energy source includes multiple sources rotating around the circumference of the container. In still further arrangements, multiple energy sources at fixed locations, as well as fixed annular radiant energy sources, are provided.

[0010] In each of the above, the primary radiant energy source is located in close proximity to the area of film on which energy absorption is desired to shrink the film. These methods are not particularly efficient in directing the radiant energy to areas of the film which are to be shrunk. For example, an unnecessary amount of heat is generated in the lid area, leading to potential heating of the contents of the cup. In addition, in those structures where moving parts are necessary, additional maintenance requirements generally follow. Further, a substantial amount of energy is wasted as it is not directed to the area where shrinkage is desired, leading to a slower sealing process and/or higher energy requirements.

[0011] It is also desired to provide for holes in the lid for straw insertion. The method currently used with the above device involves perforating the preshrunk plastic, generally in a slit in the center of the film. Through use, it has been determined that this type of perforation is non-optimal because it provides little or no resistance to tearing. That is, when a user places a straw in the pre-perforated area, the straw hole tends to tear along the precut line. It is also desirable to clearly identify the contents of the cup. Currently, the film is preprinted with different option for the contents, including “soda”, “diet”, and “water”. After the lid is placed on the cup, the operator must use a pen, or other marking device, to manually mark the contents of the cup.

[0012] The present invention provides a reflective hood which more effectively directs the radiant energy to the areas where shrinkage is desired. Thus, the lidding time is reduced because the energy is more efficiently delivered to the shrinkage area as compared to lidding systems having multiple rotating or fixed sources, also resulting in a reduction in the amount of heat generated. In a preferred embodiment, light from a light source above the cup mouth is redirected and concentrated to fall on the area of the film adjacent to the lip of the cup. Regarding straw insertion and identifying the contents of the container, the present invention provides a reflective shield having one and preferably two or more apertures, which allow radiant energy to pass through the reflective shield and impinge on the film causing it to shrink. One aperture in the shield may be provided for making a location for straw insertion, while additional apertures may be provided for identifying the contents of the container. It will be obvious to one of ordinary skill in the art that the reflective shield can have one aperture that will allow radiant energy to pass through for providing either a location for straw insertion or providing for identifying the contents of the container, or that alternative radiant energy sources without a reflective hood can be used.

[0013] Further advantages of the invention will be set forth in part in the description which follows and in part will be apparent from the description or may be learned by practice of the invention. The advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.

SUMMARY OF THE INVENTION

[0014] As embodied and broadly described herein, the invention includes a reflective hood system for heat-shrinking a film onto an open-topped container comprising a reflective hood having a reflective surface, a radiant energy source, and a reflective shield, wherein the reflective shield is located at or near an opening in the reflective hood, and wherein the reflective shield has at least one optical aperture, an optical aperture including an optical surface having areas of higher and lower reflective capability. A reflective hood assembly of the present invention may further include a reflective shield having two optical apertures. Moreover, the invention may comprise a protective optical element, wherein the protective optical element is provided at the opening in the reflective hood. In other embodiments of the present invention, the reflective hood will take the form of a shell, preferably a curvilinear shell. In still another embodiment, the curvilinear shell will have a surface of revolution. In yet another embodiment, the reflective hood as a double ellipsoidal shape, as hereinafter defined.

[0015] In another embodiment of the invention, a secondary radiant energy source or sources can be located under the reflective shield, providing radiant energy for marking the film. If two or more secondary radiant energy sources are used, one radiant energy source can be positioned for marking the film for straw insertion, while the other radiant energy sources can be positioned to identify the contents of the open-topped container. In yet another embodiment, secondary radiant energy sources can be located external to the reflective hood. In this arrangement, the optical apertures can extend through the reflective hood and shield.

[0016] The invention also includes a method of heat-shrinking film onto an open-topped container comprising the steps of contacting the top of an open-topped container with a heat shrink film, placing the covered open-topped container at an opening of a reflective hood, wherein a portion of the opening of the reflective hood is covered by a reflective shield, wherein the reflective shield has at least one optical aperture, and activating a radiant energy source, the radiant energy source emitting radiant energy preferably having visible and near infrared wavelengths, wherein a first portion of the radiant energy reflects along a surface of the reflective hood and is ultimately directed to an area below the brim of the open-topped container, thereby shrinking the heat-shrink film, wherein a second portion of the radiant energy reflects off a surface of the reflective shield and contacts a surface of the reflective hood and is ultimately directed to an area below the brim of the open-topped container, thereby shrinking the heat-shrink film, and, wherein a third portion of the radiant energy passes through at least one optical aperture and impinge on the thin film, thereby leaving a visible mark or weak spot. The reflective shield can also have two or more optical apertures. In one embodiment the method includes a reflective hood assembly having a protective optical element, wherein the protective optical element is provided at the opening in the reflective hood, and that the reflective hood comprises at least four angularly displaced surfaces. In another embodiment the reflective hood has a curvilinear surface of revolution. In yet another embodiment, the reflective hood is a double ellipsoidal hood.

[0017] The accompanying drawings, which are incorporated herein and constitute a part of this specification, illustrate an embodiment of the invention, and, together with the description, serve to explain the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] FIG. 1 illustrates a reflective hood assembly according to an embodiment of the present invention.

[0019] FIG. 2 illustrates a reflective hood assembly according to a second embodiment of the present invention.

[0020] FIGS. 3 and 3A illustrate a rotationally mounted reflective shield according to a preferred embodiment of the present invention.

[0021] FIG. 4 illustrates a reflective shield according to a preferred embodiment of the present invention.

[0022] FIG. 5 illustrates a marking template according to a preferred embodiment of the present invention.

[0023] FIG. 6 illustrates a thin film for use in the present invention.

[0024] FIG. 7 illustrates a reflective shield according to another preferred embodiment of the present invention.

[0025] FIG. 8 illustrates a marking template according to another preferred embodiment of the present invention.

[0026] FIG. 9 illustrates another embodiment of the present invention.

[0027] FIG. 10 illustrates yet another embodiment of the present invention.

DESCRIPTION

[0028] Reference will now be made in detail to the present embodiments of the invention, examples of which are illustrated in the accompanying drawings. While the following description is directed to open-topped containers, such as cups, those of ordinary skill in the art will appreciate that the invention is equally applicable to other open-topped containers, such as food cartons.

[0029] In accordance with the invention, as broadly described, the reflective hood system includes a radiant energy source, a reflective hood, a reflective shield, and a protective optical element. In addition, the reflective hood system can include a stationary plate. In general, the radiant energy source emits radiant energy preferably in the form of visible and near infrared radiation. A portion of the emitted radiant energy contacts the surface of the reflective hood at an angle and reflects along the reflective hood until finally being directed toward a thin film that will shrink when impinged on by visible and near infrared radiation. A second portion of the radiant energy contacts the solid portions of the reflective shield at an angle, reflects back to and along the reflective hood until finally being directed to the thin film. A third portion of the radiant energy passes through the optical apertures in the reflective shield.

[0030] In the present invention, film is provided covering the top of, and extending downwardly past the brim of, an open-topped container, such as a drinking cup. The radiant energy from the radiant energy source is directed to the area just below the periphery of the top of the cup, i.e., just below the brim. Thus, the radiant energy causes the film to shrink in the area around the brim, thereby forming a lid. In one embodiment the film is a bi-axially oriented thin shrink film having a preferred thickness of between 40 to 120 gauge (1.02 mm to 3.05 mm), with a more preferred film having a thickness of between 60 to 100 gauge (1.52 mm to 2.54 mm). One film that has been used is a 75 gauge (1.91 mm) DuPont Clysar ABL polyolefin shrink film. Appropriate shrink film would be readily apparent to the skilled artisan. Any art recognized film would be appropriate, such as 75 gauge (1.91 mm) Intertape Exfilm polyolefin shrink film. When used to cover food products, the film should be food-grade and food contact-approved by the appropriate regulatory authorities.

[0031] To ensure that the film sufficiently shrinks when contacted by radiant energy, it is generally desired for the film to be coated with a radiant energy absorbing substance. One such substance that works well in this environment is carbon black pigment. Other substances that would achieve satisfactory results include graphite and iron oxide. In a preferred embodiment, the carbon black pigment may be included as a functional component in ink that is applied to the surface of the film.

[0032] In one embodiment of the present invention at least two ink layers are applied to the film. One layer is a reflective layer and the second layer is a radiant energy absorbing layer. The radiant energy absorbing layer preferably contains an energy absorbing substance, such as carbon black, which increases the shrink rate of the film. The reflective layer acts as a reflector and reflects some of the radiant energy that passes through the energy absorbing layer back to the energy absorbing layer, thereby increasing the amount of energy absorbed by the energy absorbing layer.

[0033] Two ink systems that have been found to be adequate for use with the current invention are described below. Those of ordinary skill in the art will understand that there are a variety of ink systems, having one or more ink layers, that can be used with the present invention.

[0034] According to one embodiment, in a two layer ink system, the film may include a white ink, i.e., reflective layer, and a maroon ink, i.e., energy absorbing layer. In a preferred energy absorbing layer, carbon black is mixed into the maroon layer. To enhance shrinkage of the film, it is preferred that carbon black be added at a concentration of at least approximately 6% by dry weight of the ink formulation. In addition, it is preferred that at least 0.03 lbs. of carbon black be added to every 3000 sq. ft. of printed area of the film. Those of ordinary skill in the art will understand that a variety of ink concentrations can achieve satisfactory results in the present invention. The white layer acts as a reflector so that the radiant energy that passes through the maroon layer will be reflected back towards the maroon layer, thereby enhancing impingement of the maroon layer by the radiant energy. While the invention has been described in terms of a white or maroon layer, those of ordinary skill in the art will appreciate that a variety of colors can be used to achieve a reflective layer and an energy absorbing layer.

[0035] In another two layer ink system, the film is coated with an aluminum particulate silver ink and then a blue or black ink, preferably with a substantial amount of a material which is highly energy absorbent for the particular energy source being utilized, such as carbon black. As with the white layer described above, the silver layer acts as a reflector so that the radiant energy that passes through the blue layer will be reflected back towards the blue layer, thereby enhancing impingement of the blue layer by the radiant energy.

[0036] A four layer ink system is preferred when lighter, more decorative, colors are desired on the top surface of the film. In particular, it is sometimes desired to apply a decorative layer above the absorbent layer. The four layer ink system has a film, silver reflective layer, an absorbent layer, a white reflective layer, and a decorative layer. The decorative layer may contain multiple colors that are lighter than the maroon and dark blue generally achieved with two layer systems. The decorative layer may also contain advertising slogans and indicia useful for identifying the contents of the lidded container.

[0037] Each of the above formulations is acceptable for use with the current invention. The four layer ink system provides acceptable film shrink and superior appearance. The two color system achieves acceptable film shrink and appearance, at a lower cost.

[0038] Those of ordinary skill in the art will understand that a variety of ink colors can be used to obtain satisfactory results with the present invention and that a varied number of ink layers can also be used. In addition, those of ordinary skill in the art will understand that it is not necessary to coat the entire film with ink. In particular, in those area where shrinkage is not desired, the ink coating need not be applied and may, in fact, be undesirable. Moreover, those of ordinary skill in the art will appreciate that ink patterns can be used on any ink layer.

[0039] According to one embodiment of the invention, and as shown in FIG. 1, the reflective hood assembly 10 includes a radiant energy source 12, a reflective hood 14, a reflective shield 16, and a stationary plate 60 (see FIG. 3). The radiant energy source 12 produces radiant energy for shrinking a film 20 by emitting radiant energy having wavelengths in the visible and near infrared range. Those of ordinary skill in the art will understand that the wavelength of the energy emitted by the radiant energy source is not particularly critical so long as the ink chosen is sufficiently absorbent over a range of the wavelengths emitted so that film shrinkage is reasonably rapid. Of course, it is preferred to insure that the surfaces serving as reflectors are actually reflective for radiation in the chosen wavelengths, if radiation outside the visible range is emitted.

[0040] In particular, a convenient radiant energy source 12 is a conventional halogen lamp emitting light energy having wavelengths at least between approximately 600-1400 nm. It has been found that tungsten halogen lamps are a preferred radiant energy source 12, however, those of ordinary skill in the art will understand that a number of different radiant energy sources are available which produce sufficient visible and near infrared radiation, such as xenon arc lamps. The energy source is preferred to have a wattage of between 150-1000 watts for compatibility with standard electrical wiring/circuiting.

[0041] The reflective hood 14 reflects the radiant energy emitted from the radiant energy source 12 and directs it to the area where film shrinkage is desired, i.e., the target area. The reflective hood 14 depicted in FIG. 1 is constructed of a series of frusto-conical surfaces 14a-14d located at angles with respect to each other forming a reflector which is generally concave downward. In operation, as radiant energy contacts one of the surfaces 14a-14c it will be reflected such that it either directly, or through a series of reflections, contacts the lowermost surface 14d. The lower most reflection surface 14d is shaped to cause the radiant energy to reflect from the surface and impinge on the desired shrinkage area. It is preferred that the inner surface of the reflective hood 14 have a smooth, mirror-like surface to aid in reflecting the radiant energy. In one embodiment the inner surface has a metallized silver-coated or gold-coated mirrored surface to reduce reflection losses. Those of ordinary skill in the art will understand that there are a variety of surfaces and coatings that can be used to reflect radiant energy. In addition, those of ordinary skill in the art will understand that similar results can be achieved using different numbers of surfaces and shapes.

[0042] The reflective shield 16 is a cover that substantially prevents radiant energy from contacting certain areas of the film 20 located over the mouth of the cup, keeping those areas free from shrinking. In addition, the reflective shield reflects the radiant energy, directing it back to the reflective hood 14, where it is eventually directed to the target area. The reflective shield 16 is shaped to form an opposing side to the curve-shaped reflective hood 14 so as to optimize reflection of the radiant energy. For instance., as shown in FIG. 1 it is desired that the radiant energy generally not impinge on a portion of the area of the film 20 covering the open portion of the container 22. Accordingly, the reflective shield is positioned over the top of the film 20 to prevent the radiant energy from impinging a portion of the film positioned over the open portion of the beverage container 22. The reflective portion of the reflective shield 16 is constructed such that it prevents visible and near-infrared radiant energy from penetrating through the shield. It is preferred that the reflective portion of the reflective shield 16 have a surface that reflects radiant energy as discussed above.

[0043] In one embodiment the reflective portion of the reflective shield 16 has a metallic mirrored surface to more efficiently reflect the radiant energy. Thus, when the radiant energy source 12 emits radiant energy, some of the radiant energy is directed to the area covered by the reflective shield 16. This radiant energy reflects off the reflective shield 16, contacts the reflective hood 14, and is directed through a reflection, or a series of reflections, to the target area.

[0044] In one embodiment, the reflective shield 16 has a first optical aperture 44 for allowing radiant energy to pass through the shield 16 and impinge on the surface of the film 20 covering the container 22. As shown in FIG. 4, the first optical aperture 44 is larger than the average diameter of a drinking straw, such that the area impinged on by the radiant energy is larger than the drinking straw, e.g., approximately ½″. In operation, when the radiant energy impinges on the film 20 the activated portion of the film 20, which is preferably printed with an energy absorbing substance, retracts from the center of the aperture area, leaving a substantially circular area having a film 20 membrane that is thinner than the area not impinged on by radiant energy. The thinner areas are weaker, allowing a straw to be inserted with less force. In addition, as the film 20 retracts, an outer ring of thicker film is formed providing a strengthening annulus. The strengthening annulus assists in preventing film 20 tearing after the straw is inserted.

[0045] In one embodiment, the first optical aperture 44 should be an opening in the reflective shield 16. Those of ordinary skill in the art will appreciate, however, that the film can be marked by providing first optical aperture 44 in the reflective shield 16 that allows more radiant energy to pass through than can pass through other portions of the reflective shield 16. For example, the reflective shield 16 may have no unobstructed openings therethrough, but may have an area that does not reflect radiant energy to the level that it is reflected through other portions of the reflective shield 16.

[0046] In yet another embodiment, the reflective shield 16 has a second optical aperture 46 for allowing radiant energy to pass through the shield 16 and impinge on the surface of the film 20 covering the container 22. The second optical aperture 46 can be used to identify the contents of the container 22. In particular, the film 20 can be manufactured having the various beverage options, such as “soda”, “diet”, and “water”, imprinted on the film. Moreover, the film 20 can be manufactured having a plurality of interiorly located heat shrinkable target regions, where each of the target regions has indicating means for identifying the contents of the container when the target regions are exposed to radiant energy.

[0047] When selecting a various beverage option, the second optical aperture 46 is positioned such that radiant energy impinges on the surface of the film in the vicinity of the desired option, or target region. For example, if the container 22 is filled with water, the second aperture 46 is positioned such that the radiant energy passes through and makes a mark on the film 20 under the “water” position. It is necessary, however, that the area to be marked contain energy absorbing material, such as ink containing carbon black. In one embodiment, the drink selections on the film 20 are provided with a contrasting background such that when the film 20 is marked the selection is easily identifiable. As noted above with regard to the first optical aperture 44, it is not necessary that the second optical aperture 46 be an unobstructed opening in the reflective shield 16.

[0048] In another embodiment of the present invention, as shown in FIGS. 3-5, a template 60 is positioned under the reflective shield 16. An elongated slot 64, positioned underneath the first optical aperture 44 is provided for marking the location for straw insertion. In addition, the template 60 is engraved with a marking pattern 62 for use in identifying the contents of the beverage container, as shown in FIG. 5. There are a large variety of marking patterns that can be used, including and arrow, a circle of dots that will encircle the word, a check mark, a dot, etc. (See FIG. 6.) For example, if there are four different possibilities for the contents of the container, i.e., “cola”, “diet”, “water”, and “other”, there may be four engravings, e.g., arrows, dots, circle of dots, words, etc., on the template 60. The marking pattern 62 is in alignment with the selections on the film 20. Those of ordinary skill in the art will understand that any number of marking patterns 62 can be used and that the marking patterns 62 can be intermixed on the template 60. In one embodiment, a blank, solid background is provided as a target for the arrows, dots, circle of dots, words, etc.

[0049] In one embodiment, as depicted in FIGS. 3 and 3A, the reflective shield 16 is rotationally mounted on a stationary axis 48, thereby allowing the shield 16 to be rotated into position for marking the film 20. The reflective shield 16 can be rotated via a cable 66 attached to the center rotating area with a linear slide action on front of the unit. In this embodiment, the reflective shield 16 may have a locking selection mechanism that allows accurate location of the second aperture 46 over the desired selection location. For example, as shown in FIG. 4, the edge of the reflective shield 16 has a series of positioning grooves 50. As further shown, an interlocking pin 52 fits within the grooves 50. The pin is biased by a spring 54, such that when no external force is applied, the reflective shield 16 is locked into place. To change the position of the reflective shield 16, and hence to mark a different identification on the lid, the reflective shield 16 is rotated by means of a cable 66 and a slide 80, the slide 80 having an indicator #, which is aligned under a label on the indicator 82 that tells the user which drink has been selected, until the biased pin is locked into the appropriate groove. When marking the film 20, the reflective shield 16 is rotated such that radiant energy will pass through the first optical aperture 44 and the elongated slot 64 for marking the location of the straw insertion area and radiant energy will also pass through the second optical aperture 46 and the marking pattern 62 for marking the drink selection.

[0050] In yet another embodiment, the reflective shield 16 is constructed in two pieces, a center conical section 16a and an outer frusto-conical section 16b, as depicted in FIG. 7. The center conical section 16a is stationary and has a first optical aperture 44. The first optical aperture 44 is provided for marking the film 20 for a location for straw insertion. As the center conical section 16a is stationary, the location for straw insertion is always located on the film at the same location. The outer frusto-conical section 16b is rotationally mounted and in communication with the center conical section 16a. The outer frusto-conical section 16b is provided with a second optical aperture 46 for marking the drink selection. As described above, to select the appropriate drink marking, the outer frusto-conical section 16b is rotated to place a mark in the proper location.

[0051] In still another embodiment, as depicted in FIG. 8, the reflective shield 16 is rigidly mounted, while the template 60 is rotationally mounted on an axis. In this arrangement, first and second optical apertures 44, 46 are provided on the reflective shield 16. The template is engraved with a marking pattern 62 for use in identifying the contents of the beverage container, as depicted in FIG. 5. In addition an elongated slot 64 is provided for marking the location for straw insertion. When marking the film 20, the template 60 is rotated such that the radiant energy passes through the first optical aperture 44 and the elongated slot 64 for marking the location for straw insertion and radiant energy also passes through the second optical aperture 46 and the marking pattern 62 for marking the drink selection. Those of ordinary skill in the art will understand that there are a variety of configurations available using the reflective shield 16 and template 60 for marking the film 20.

[0052] In the embodiment depicted in FIG. 1, the radiant energy source 12, reflective hood 14, and reflective shield 16 are protected by a protective optical element 18, although the apparatus will function without the protective optical element 18 in place. The protective optical element 18 prevents liquids from contacting the radiant energy source 12, the reflective hood 14, and the reflective shield 16.

[0053] In operation, the beverage container 22 is filled with a liquid beverage, such as water, soda, carbonated or non-carbonated, or coffee. During the lidding operation, described below, liquid could potentially splash onto parts of the reflective hood assembly 10, such as the radiant energy source 12, reflective hood 14, or reflective shield 16, causing damage or reducing efficiency. The protective optical element 18 is preferably integral with the reflective hood assembly 10. The protective optical element 18 must be constructed of materials that minimize loss of radiant energy allowing sufficient radiant energy to pass through and contact the film. It is preferred that the protective optical element 18 be constructed of plastic, or more preferably, of glass. Those of ordinary skill in the art will understand that a variety of materials can be used to construct the protective optical element 18.

[0054] The lidding operation of the described apparatus will now be explained. After the beverage container 22 is filled with the desired beverage, the operator places the beverage container 22 in contact with the film 20 and in proximity of the reflective hood assembly 10. As the beverage container 22 is placed into position, the radiant energy source 12 is activated, emitting radiant energy. The radiant energy emits diffusely in all directions contacting either the reflective hood 14 or the reflective shield 16. Through either one or a series of reflections, the radiant energy contacts the lowermost reflection surface 14d, which directs the radiant energy to the desired shrinkage area of the film 20 located around the brim of the beverage container 22. As the radiant energy impinges on the film 20, radiant energy is absorbed and the film 20 shrinks, forming a seal around the lid of the beverage container 22. The beverage container 22 is then removed from the reflective hood assembly 10.

[0055] In another embodiment, as shown in FIG. 2, the double ellipsoidal structure is formed by the curvatures of the reflective hood 14 and the reflective shield 16. The reflective hood assembly 10 has a double ellipsoidal structure that improves the efficiency in delivering the radiant energy to the target shrinkage area. The first or primary ellipsoid 24 is defined by the inner surface of the reflective hood 14 and the upper surface of the reflective shield 16. Unlike the reflective hood 14 depicted in FIG. 1, the reflective hood 14 has a largely curvilinear surface of revolution. The primary ellipsoid 24 has a focal point 28 and a focal ring 30. The focal point 28 is located coincident with the radiant energy source 12, which is attached to the assembly 10 at the upper end of the primary ellipsoid 24 in the vicinity of the radiant energy source 12. The focal ring 30 is located at the lower end of the primary ellipsoid 24. In operation, the radiant energy emitted from the radiant energy source 12 passes from the focal point 28 and through the focal ring 30. Because of the curvilinear surface of revolution of the reflective hood 14 wall, the majority of the radiant energy that does not flow directly from the focal point 28 through the focal ring 30, but instead contacts the reflective hood 14 or the reflective shield 16, will reflect off the reflective hood 14 or the reflective shield 16 and through the second focal point 30.

[0056] The secondary ellipsoid 26 is defined by the lower portion of the reflective hood 14. The secondary ellipsoid 26 has two focal rings 30, 32. The lower portion of the reflective hood 14 is configured such that the focal ring 30 of the second ellipsoid ring is common with the first ellipsoid focal ring 30. Moreover, the lower portion of the reflective hood 14 is configured such that the second focal ring 32 of the secondary ellipsoid 26 is located near the shrinkage target area of the film 20. When the radiant energy passes through the secondary ellipsoid first focal ring 30, as described above, the radiant energy reflects off the surface of the reflective hood 14. Because of the curvilinear surface of revolution of the lower portion of the reflective hood 14, the radiant energy reflects off of the lower portion of the reflective hood 14 then passes through the secondary ellipsoid second focal ring 32 and impinges on the film 20 at the shrinkage target area. It is preferred that the shrinkage target area be located just below the brim of the opening of the beverage container 22, such that when the radiant energy contacts the film 20, a seal is formed below the lid of the beverage container 22.

[0057] The reflective shield 16 of this embodiment, which prevents radiant energy from impinging portions of the surface of the film 20, may be a curved reflective part of the first ellipsoidal 24 surface. The surface of revolution of the reflective shield 20, as shown in FIG. 2, is designed to reflect the radiant energy that contacts it such that it reflects off the reflective hood 14 and passes through the second focal point 30. As noted above, it is preferred that the reflective shield 16 have a metallic mirrored surface.

[0058] Those of ordinary skill in the art will readily understand how to determine the dimensions for a double ellipsoidal reflective hood for effectively directing the radiant energy to the target area. An example of the calculations for determining the dimensions are set forth in the following example.

[0059] The following equations can be used to determine the ellipsoids:

Major Axis (length of primary ellipsoid): 2a=2b+2c

Major Axis (length of secondary ellipsoid): 2d=2e+2f

[0060] where

[0061] 2b,2e=the distance between the focal points of each ellipsoid; and

[0062] c,f=the distance from foci to the edge of the ellipse at the apex.

[0063] To determine the dimensions, the “c” distance (for the primary ellipse), which is dependent upon the size and shape of the radiant energy source being used, must be selected. In addition, the distance between the focal points of the large ellipse, “2b”, which is the distance needed for the largest cup, must be selected. After determining the desired energy profile at the cup, the following selections were made:

[0064] For the primary ellipse: c=0.2″ and 2b=5″

[0065] For the secondary ellipse: f=0.2 and 2e=1″

[0066] Using the above values, the dimensions of the ellipses were determined. Understanding that the primary and secondary ellipses share a common focal point, the secondary ellipse was rotated −25 degrees about the common focal point. Then, both the primary and secondary ellipses were rotated 45 degrees about the focal point coincident with the radiant energy source.

[0067] As described above, in one embodiment, the reflective shield 16 has a first optical aperture 44 for allowing radiant energy to pass through the shield 16 and impinge on the surface of the film 20 covering the container 22. As shown in FIG. 2, the first optical aperture 44 is larger than the average diameter of a drinking straw, such that the area impinged on by the radiant energy is larger than the drinking straw. In operation, when the radiant energy contacts the film 20, the activated portion of the film 20 retracts from the center of the aperture area, leaving a substantially circular area having a film 20 membrane that is thinner than the area not impinged on by radiant energy. The thinner area is weaker, allowing a straw to be inserted with less force. In addition, as the film 20 retracts, an outer ring of thicker film is formed providing a strengthening annulus. The strengthening annulus assists in preventing film 20 tearing after the straw is inserted.

[0068] In another embodiment the reflective shield 16 has a second optical aperture 46 for allowing radiant energy to pass through the shield 16 and impinge on the surface of the film 20 covering the container 22. The second optical aperture 46 can be used to identify the contents of the container 22. In particular, the film 20 can be manufactured having the various beverage options, such as “soda”, “diet”, and “water”, imprinted on the film. The second optical aperture 46 is then positioned such that radiant energy contacts the surface of the film in the vicinity of the desired option. For example, if the container 22 is filled with water, the second optical aperture 46 is positioned such that the radiant energy will pass through and make a mark on the film 20 under the “water” position. It is preferred, however, that the area to be marked contain energy absorbing material, such as ink containing carbon black. In one embodiment, the drink selections on the film 20 are provided with a contrasting background such that when the film 20 is marked the selection is easily identifiable.

[0069] In yet another embodiment, as shown in FIG. 3, a template 60 is positioned under the reflective shield 16. An elongated slot 64, positioned underneath the first optical aperture 44 is provided for marking the location for straw insertion. In addition, the template 60 is engraved with a marking pattern 62 for use in identifying the contents of the beverage container, as shown in FIG. 5. There are a large variety of marking patterns that can be used, including and arrow, a circle of dots that will encircle the word, a check mark, a dot, etc. For example, if there are four different possibilities for the contents of the container, i.e., “cola”, “diet”, “water”, and “other”, there may be four engravings, e.g., arrows, dots, circle of dots, etc., on the template 60. In this embodiment, the marking pattern 62 is in alignment with the selections on the film 20. In another embodiment, the possibilities for the contents of the container, e.g., “cola” or “diet” are engraved in the template 60. In this embodiment, the template 60 is used to imprint the identification of the contents on the lid. Those of ordinary skill in the art will understand that any number of marking patterns 62 can be used and that the marking patterns 62 can be intermixed on the template 60.

[0070] To allow the identification of the beverage, the reflective shield 16 may be rotationally mounted on a stationary axis 48, as shown in FIGS. 3 and 3A, thereby allowing the shield 16 to be rotated into position for marking the film 20. The reflective shield 16 can be rotated via a cable attached to the center rotating area with a linear slide action on front of the unit, as described above. The reflective shield 16 may have a locking selection mechanism that allows accurate location of the second optical aperture 46 over the desired selection location. For example, as shown in FIG. 4, the edge of the reflective shield 16 has a series of positioning grooves 50. As further shown, an interlocking pin 52 fits within the grooves 50. The pin is biased by a spring 54, such that when no external force is applied, the reflective shield 16 is locked into place. To change the position of the reflective shield 16, and hence to mark a different identification on the lid, the reflective shield 16 is rotated until the biased pin is locked into the appropriate groove. When marking the film 20, the reflective shield 16 is rotated such that the radiant energy passes through the first optical aperture 44 and the elongated slot 64 for marking the location for straw insertion and radiant energy also passes through the second optical aperture 46 and the marking pattern 62 for marking the drink selection.

[0071] In another embodiment, the reflective shield 16 is constructed in two pieces, a center conical section 16a and an outer frusto-conical section 16b, as depicted in FIG. 7. The center conical section 16a is stationary and has a first optical aperture 44. The first optical aperture 44 is provided for marking the film 20 for location of straw insertion. As the center conical section 16a is stationary, the location for straw insertion is always located on the film at the same location. The outer frusto-conical section 16b is rotationally mounted and in communication with the center conical section 16a. The outer frusto-conical section 16b is provided with a second optical aperture 46 for marking the drink selection. As described above, to select the appropriate drink marking, the outer frusto-conical section 16b is rotated to place a mark in the proper location.

[0072] In another embodiment, as depicted in FIG. 8, the reflective shield 16 is rigidly mounted, while the template 60 is rotationally mounted on an axis. In this arrangement, first and second optical apertures 44, 46 are provided on the reflective shield 16. The template is engraved with a marking pattern 62 for use in identifying the contents of the beverage container, as depicted in FIG. 5. In addition, an elongated slot 64 is provided for marking the location for straw insertion. When marking the film 20, the template 60 is rotated such that radiant energy passes through the first optical aperture 44 and the elongated slot 64 for marking the location for straw insertion and radiant energy also passes through the second optical aperture 46 and the marking pattern 62 for marking the drink selection. Those of ordinary skill in the art will understand that there are a variety of configurations available using the reflective shield 16 and template 60 for marking the film 20.

[0073] In another embodiment, depicted in FIG. 9, the marking of the film is achieved by placing a secondary radiant energy source, or sources, beneath the reflective shield 16. As shown in FIG. 9, the secondary radiant energy sources 68 are located beneath the reflective shield 16, but above the template 60. At least one of the secondary radiant energy sources 68 should be located above template 60 for marking the location for straw insertion. A second of the secondary radiant energy sources should be located above the template 60 for indicating drink selection. It is possible, when using multiple secondary radiant energy sources 68, to use a number of secondary sources 68, equivalent to the number of drink selection, in addition to the secondary source for marking the location for straw hole insertion. In this case, it is not necessary that the template be capable of rotation.

[0074] In another embodiment, depicted in FIG. 10, secondary radiant energy sources 68 are located external to the reflective hood 14. As shown in FIG. 10, when external radiant energy sources 68 are used, the straw location optical aperture 70 includes aligned apertures in the outer surface of the reflective hood 14 and the reflective shield 16. A drink marking optical aperture 72 may extend from the outer surface of the reflective hood 14 and through the reflective shield 16. In one embodiment, the optical apertures 70, 72 are enclosed such that radiant energy emitted by the primary radiant energy source 12 does not enter the optical apertures 70, 72. In another embodiment, multiple secondary radiant energy sources 68 are used for drink identification such that one secondary radiant energy source 68 is provided for each possible drink selection. In this case, it is not necessary that the template be capable of rotation. The secondary radiant energy sources 68 may be shielded, such as by a parabolic shield 74, so that the emitted radiant energy is directed towards the optical apertures 70, 72.

[0075] It is understood that the invention is not confined to the particular construction and arrangement of parts and the particular processes described herein but embraces such modified forms thereof as come within the scope of the following claims.

Claims

1. A reflective hood system for heat-shrinking a film onto an open-topped container comprising: a reflective hood having a reflective interior surface; a radiant energy source; and a reflective shield, the reflective hood and the reflective shield being configured to concentrate radiant energy from the radiant energy source about the periphery of an opening in a portion of the hood, and wherein the reflective shield has at least one optical aperture.

2. The reflective hood system according to claim 1 wherein the reflective shield has two or more optical apertures.

3. The reflective hood system according to claim 1 further comprising a protective optical element, wherein the protective optical element is provided at the opening in the reflective hood.

4. The reflective hood system according to claim 3 wherein the protective optical element is plastic.

5. The reflective hood system according to claim 3 wherein the protective optical element is glass.

6. The reflective hood system according to claim 1 wherein the interior surface is coated with a material to enhance surface reflectivity.

7. The reflective hood system according to claim 6 wherein the interior surface is coated with a gold or silver metallic reflective surface.

8. The reflective hood system according to claim 1 wherein the reflective hood comprises at least four angularly displaced frusto-conical surfaces.

9. The reflective hood system according to claim 8 wherein the interior surface is coated with a material to enhance surface reflectivity.

10. The reflective hood system according to claim 9 wherein the interior surface is coated with a gold or silver metallic reflective surface.

11. The reflective hood assembly according to claim 1 wherein the reflective hood has a curvilinear surface of revolution.

12. The reflective hood assembly according to claim 11 wherein the reflective hood is a double ellipsoidal hood.

13. The reflective hood system according to claim 12 wherein the interior surface is coated with a material to enhance surface reflectivity.

14. The reflective hood assembly according to claim 13 wherein a surface of the double ellipsoidal reflective hood is coated with a gold or silver metallic reflective surface.

15. The reflective hood assembly according to claim 1 wherein the reflective shield is rotatably mounted on an axis.

16. The reflective hood assembly according to claim 15 wherein the reflective shield has grooves capable of securing the shield in a specific position, and wherein the grooves are capable of receiving a securing device.

17. The reflective hood assembly according to claim 1 further including a template positioned beneath the reflective shield.

18. The reflective hood assembly according to claim 17 wherein the template is engraved with a pattern.

19. The reflective hood assembly according to claim 18 wherein the template is rotationally mounted.

20. The reflective hood assembly according to claim 12 wherein the double ellipsoidal reflective hood has first and second focal rings, and wherein one of the first or second focal rings is coincident with the periphery of the opening in the lower portion of the hood.

21. A method of heat-shrinking film onto an open-topped container comprising the steps of: contacting the top of an opening of an open-topped container with a heat-shrink film; placing the covered open-topped container at an opening of a reflective hood, wherein a portion of the opening of the reflective hood is covered by a reflective shield, and wherein the reflective shield has at least one optical aperture; and subjecting the covered container to radiant energy having visible and near infrared wavelengths.

22. The method according to claim 21 wherein a first portion of the radiant energy reflects along a surface of the reflective hood and is ultimately directed to an area below the brim of the open-topped container, thereby shrinking the heat-shrink film, wherein a second portion of the radiant energy reflects off a surface of the reflective shield and contacts a surface of the reflective hood and is ultimately directed to an area below the brim of the open-topped container, thereby shrinking the heat-shrink film, and, wherein a third portion of the radiant energy passes through at least one optical aperture and impinges on the thin film.

23. The method according to claim 21 wherein the reflective shield has two or more optical apertures.

24. The method according to claim 21 further comprising a protective optical element, wherein the protective optical element is provided at the opening in the reflective hood.

25. The method according to claim 24 wherein the protective optical element is plastic.

26. The method according to claim 24 wherein the protective optical element is glass.

27. The method according to claim 21 wherein the interior surface of the reflective hood is coated with a material to enhance surface reflectivity.

28. The method according to claim 27 wherein the interior surface is coated with a gold or silver metallic reflective surface.

29. The method according to claim 21 wherein the reflective hood comprises at least four angularly displaced frusto-conical surfaces.

30. The method according to claim 29 wherein the interior surface of the reflective hood is coated with a material to enhance surface reflectivity.

31. The method according to claim 30 wherein the frusto-conical surfaces are coated with a gold or silver metallic reflective surface.

32. The method according to claim 21 wherein the reflective hood has a curvilinear surface of revolution.

33. The method according to claim 32 wherein the reflective hood is a double ellipsoidal hood.

34. The method according to claim 33 wherein the interior surface of the reflective hood is coated with a material to enhance surface reflectivity.

35. The method according to claim 34 wherein a surface of the double ellipsoidal reflective hood is coated with a gold or silver metallic reflective surface.

36. The method according to claim 21 wherein the reflective shield is rotatably mounted on an axis.

37. The method according to claim 36 wherein the reflective shield has grooves capable of securing the shield in a specific position and wherein the grooves are capable of receiving a securing device.

38. The method according to claim 36 further including the step of rotating the reflective shield.

39. The method according to claim 21 further including a template positioned beneath the reflective shield.

40. The method according to claim 39 wherein the template is engraved with a pattern.

41. The method according to claim 39 wherein the template is rotatably mounted.

42. The method according to claim 33 wherein the double ellipsoidal reflective hood has first and second focal rings, wherein one of the first or second focal rings is coincident with the periphery of the opening in the lower portion of the hood, and wherein the radiant energy is concentrated at the focal ring coincident with the periphery of the opening in the lower portion of the hood.

43. A reflective hood system for heat-shrinking a film onto an open-topped container comprising: a reflective hood capable of concentrating energy from a radiant energy source onto an area of the film which is to be shrunk and onto a reflective shield; and the reflective shield having at least one optical aperture.

44. A reflective hood system for heat-shrinking a film onto an open-topped container comprising: a reflective hood having a reflective interior surface; a first radiant energy source; a reflective shield, the reflective hood and the reflective shield being configured to concentrate radiant energy from the first radiant energy source about the periphery of an opening in a portion of the hood; a template positioned beneath the reflective shield; and a second radiant energy source located between the reflective shield and the template.

45. A reflective hood system for heat-shrinking a film onto an open-topped container comprising: a reflective hood having a reflective interior surface; a first radiant energy source; a reflective shield, the reflective hood and the reflective shield being configured to concentrate radiant energy from the first radiant energy source about the periphery of an opening in a portion of the hood; and at least one secondary radiant energy source located external to the reflective hood, wherein the secondary radiant energy source is in optical communication with the film.

46. A reflective hood system for heat-shrinking a film onto an open-topped container comprising a reflective hood and a reflective shield, the reflective shield having at least one aperture, wherein the reflective hood and the reflective shield are capable of concentrating energy from a radiant energy source onto areas of the film which are to be shrunk.

47. The reflective hood system according to claim 46 wherein the reflective shield has two or more optical apertures.

48. The reflective hood system according to claim 46 further comprising a protective optical element, wherein the protective optical element is provided at the opening in the reflective hood.

49. The reflective hood system according to claim 48 wherein the reflective hood has a reflective interior surface.

50. The reflective hood system according to claim 48 wherein the reflective hood includes a radiant energy source.

51. The reflective hood system according to claim 50 wherein the reflective hood and the reflective shield are configured to concentrate at least a portion of the radiant energy from the radiant energy source about the periphery of an opening in a portion of the hood.

52. The reflective hood system according to claim 48 further comprising a protective optical element, wherein the protective optical element is provided at the opening in the reflective hood.

53. The reflective hood system according to claim 52 wherein the protective optical element is plastic.

54. The reflective hood system according to claim 52 wherein the protective optical element is glass.

55. The reflective hood system according to claim 49 wherein the interior surface is coated with a material to enhance surface reflectivity.

56. The reflective hood system according to claim 55 wherein the interior surface is coated with a gold or silver metallic reflective surface.

57. The reflective hood system according to claim 46 wherein the reflective hood comprises at least four angularly displaced frusto-conical surfaces.

58. The reflective hood system according to claim 57 wherein the interior surface is coated with a material to enhance surface reflectivity.

59. The reflective hood system according to claim 58 wherein the interior surface is coated with a gold or silver metallic reflective surface.

60. The reflective hood assembly according to claim 46 wherein the reflective hood has a curvilinear surface of revolution.

61. The reflective hood assembly according to claim 60 wherein the reflective hood is a double ellipsoidal hood.

62. The reflective hood system according to claim 61 wherein the interior surface of the double ellipsoidal hood is coated with a material to enhance surface reflectivity.

63. The reflective hood assembly according to claim 62 wherein a surface of the double ellipsoidal reflective hood is coated with a gold or silver metallic reflective surface.

64. The reflective hood assembly according to claim 46 wherein the reflective shield is rotatably mounted on an axis.

65. The reflective hood assembly according to claim 64 wherein the reflective shield has grooves capable of securing the shield in a specific position, and wherein the grooves are capable of receiving a securing device.

66. The reflective hood assembly according to claim 46 further including a template positioned beneath the reflective shield.

67. The reflective hood assembly according to claim 66 wherein the template is engraved with a pattern.

68. The reflective hood assembly according to claim 67 wherein the template is rotationally mounted.

69. The reflective hood assembly according to claim 61 wherein the double ellipsoidal reflective hood has first and second focal rings, and wherein one of the first or second focal rings is coincident with the periphery of the opening in the lower portion of the hood.