MX2007016296A - Multi-layer, light markable media and method and apparatus for using same. - Google Patents

Abstract

A multi-layer laminate media is provided on which information may be applied in machine or human readable form on a visible front surface by the output of one or more lasers, or other high intensity light source. In a preferred embodiment, the media has three layers including a substrate, a thermochromic layer and a light absorbent layer located intermediate the media substrate and the thermochromic layer. The light absorbent layer is adapted to absorb light from the light source and convert the absorbed light into heat. The heat is immediately conducted into selected portions of the thermochromic layer which is in thermal contact with the light absorbent layer, causing portions of the thermochromic layer to change visual appearance such as color to create the desired mark. The media optimally includes obscuration materials to reduce the visibility of the light absorbent layer to the naked eye. The light absorbent layer is preferably a low cost absorber such as carbon black. An alternate form of the invention is a two layer laminate media including a substrate and a thermochromic layer. The invention is usable in conjunction with labeling produce items. The invention includes a method and apparatus for using media in conjunction with labeling produce items.

Description

MEDIA MARCHABLE WITH LIGHT, MULT C &PA AND METHOD AND .. TO USE THE SAME BACKGROUND AND SUMMARY OF XA XNV --- NC - OKT The present invention relates, generally, to laser (or other high intensity light) marking means used, for example, as markings on marking machines and / or in film printing for packaging, or for other printing applications, including point of sale printers, fax machines and laminated cards (eg, identity cards). The marking and packaging markets are demanding marking systems that are faster, cheaper, able to mark non-flat surfaces that have a longer life time, and that are capable of marking labels or packaging films "on the fly". As is known from the prior art, marking with a direct laser arrangement of high volume label media has numerous advantages: no ink or ribbon, no contact (giving a longer life time to appearance), and allowing non-flat media or print on non-flat substrates; (See published PCT patent application WO 05/049332 - published 06/02/05.) Diode laser arrays that provide a low resolution solution are also known from the prior art. cost, compact, high speed, high reliability to mark rolls of labels to be applied to products. A major disadvantage of the direct laser marking systems of the prior art is that they require NIR (near infrared) wavelength means of diode lasers. A traditional method requires a NIR absorber (near infrared) with a narrow absorption band, because no residual absorption in the visible wavelength range will cause visible coloration of the media. In most cases, white or clear media are preferred, so that coloring is undesirable. Additionally, shortband NIR absorbers can be expensive, adding significantly to the cost of media, when used in applications such as product packaging / labeling, where costs need to be extremely low. The present invention overcomes the aforementioned problems with the prior art systems. The present invention includes a way to create laser marking media for NIR lasers while avoiding the need for short wave NIR absorbers. More particularly, one embodiment of the invention includes multi-layered media, markable with light "indirect", novel, where the output light of the laser (or other high intensity light) is absorbed and converted into heat by a layer of the media, is immediately thermally conducted to selected portions of a thermochromic layer, adjacent, and forms the desired image. "Indirect" marking media preferably utilizes a three-layered label sheet (in addition to any adhesive layer), including a layer of light absorbing material (preferably carbon black) that coats or is included in the front surface of a substrate. translucent plastic. The media can be "marked by the back" or "marked on the front". In the case of "marking by the back", in a mode the preferred carbon black absorbs the energy of the beam output light or laser output beams (or other high intensity light), after the beam or the beams have passed through the substrate of the translucent label, and convert the energy of the absorbed light into heat; the heat is conducted to a front or visible thermochromic layer, causing desired portions of the thermochromic layer to change color (or visual appearance) to produce the desired image. In a "front dial" mode, in one embodiment the light output beam passes through the "front of the media", i.e. the first thermochromic layer, then enters the light absorbing layer.

The present invention includes additional features to optimize the overall efficiency of the system, including the use of reflective materials, either in the thermochromic coating or on the front surface of the thermochromic coating, and in the use of darkening techniques, to darken the absorbent layer of smoke black light (or other), described in detail later. The prior art of laser-markable labels includes (in addition to WO 05/049332 noted above) the use of carbon black as a recessed layer and as a donor [see US 6,001,530 (see column 4 lines 53-58).; US 6,140,008 (see col 2, lines 57-59); US 6,207,344 (see col 2 lines 47-50); US 2005/0115920 Al (see page 2, paragraph

[0016] and US 7,021,549 (see col 3, lines 39-43).] However, that prior art does not teach or suggest the use of carbon black as the material light absorber, where the absorbed light is converted to heat and conducted to the adjacent thermochromic layer, nor does it teach or suggest a three-layered label sheet having a light absorbing core layer, a thermochromic layer and a substrate. is applicable to the automatic labeling of fruits and vegetables More particularly, the invention provides an improved laminated label structure for use in a system for applying information variable "on the fly" to labels for individual product elements. The invention generally reduces the number of labeling machines, label designs and label inventory necessary to automatically apply labels to products. The invention simplifies packaging operations and reduces costs by reducing the work and inventory of labels required to automatically mark products. A principal object of the invention is to provide multi-layered, laser-tagged media (or other high-intensity light source) for use as labels or in the printing of films incorporating a low-cost light absorbing layer for NIR lasers, avoiding At the same time, the need for short band NIR absorbers, expensive and removing the coloration of the residual medium. A further object of the invention is to provide multi-layered, markable means with "indirect" laser (or other high intensity light source), which can be marked through the front or rear surface thereof. A further object of the invention is to provide multi-layered, laser-markable media, in which a low-cost, short-band light absorbing layer, such as carbon black, for example, absorbs the laser light output and converts the light. absorbed in heat, and the absorbed heat is conducted into portions of an adjacent thermochromic layer to form the desired image.

Another object of the invention is to provide multi-layered, laser-markable media (or other high-intensity light source), which include a light absorbing layer as noted above together with darkening means to prevent the light-absorbing layer from being visible to the naked eye A further object of the present invention is to provide multilayer media for use in automatic labeling machines for applying labels to individual product elements where variable encoded information is applied to each label immediately before its application to the element of a product. A further object of the invention is to provide a laminated label design capable of having variable encoded information applied thereto after the label has been transferred to the tip of the bellows in a rotating bellows applicator, which requires only minor modifications to the rotating bellows of the label applicator machine. A further object of the invention is to provide a laminated label that can have the variable encoded information applied thereto for use in a rotating bellows applicator without having to reduce the operating speed of the rotary bellows applicator. The additional objectives and advantages will become evident from the following description and the drawings where: BRIEF DESCRIPTION OF THE FIGURES FIGS. A and IB are schematic representations illustrating the "marking on the back" of the laminated three layer media of the present invention. Figures 2A and 2B are schematic illustrations of the "front marking" technique to mark three layer media of the present invention; Figures 3A and 3B illustrate the multilayer media 60 of Figures IA and IB including optional dimming means; Figure 4 is a schematic illustration of the means 60, as shown in Figures IA and IB, where the light absorbing layer is included in the substrate, as opposed to that supported on the surface of the substrate layer; Figure 5A is a schematic representation of the means of Figures IA and IB further having an optional reflector coating applied to the front surface of the media; Figure 5B is a schematic representation of the means of Figures IA and IB illustrating the Optional protective coating; Figures 6 and 7 are perspective illustrations of portions of an automatic product labeling machine, in which the labels of the present invention are advantageously used; Figure 8 is a schematic illustration showing the use of the "back marking" technique for marking the three layer sheet of the present invention on the product labeling machine illustrated generally in Figures 6 and 7; Figures 9A and 9B are schematic illustrations showing how light energy is absorbed by the central light absorbent layer, converted to heat and conducted to selected portions of the thermochromic layer to produce the desired marking; Figures 10A-10F illustrate the use of reflective materials in the thermochromic layer to cause the reflected output beam to pass through the light absorbing layer, a second time to increase the overall efficiency of the art; Figures HA and 11B are illustrations of what a typical brand produced by the invention would look like; the figure HA shows the typical dimensions and Figure 11B illustrates a real size of a typical mark; and Figure 12 is a schematic representation of A two-layered form of the invention includes a substrate layer and a thermochromic layer.

DETAILED DESCRIPTION OF THE IGÜ? Marking the "Rear Side" of the Three Layers Means Figures IA and IB illustrate the total concept of "marking the back" of a novel multilayer laminated label 60. The label 60 comprises a translucent plastic substrate 61 having a rear surface 61a and a front surface 61b. A layer of the light absorbing material 62 (preferably carbon black) to be treated by the front surface 61b of the substrate 60 to be applied by a film supported by the front surface 61b of a substrate 61 or to be included in the adjacent substrate 61 to the front surface 61b of the substrate 61. A thermochromic layer 63 is preferably supported by and is in thermal contact with the front surface 62b of the light absorbing layer 62. The thermochromic layer 63 has a back surface 63a and a front surface 63b. The front surface 63b forms a visible, front surface of the label 60. The output 41 of the laser coding means (or high intensity light source) 40 is partially absorbed by the light absorbing layer 62 and converted to heat. The light source 40 may be one or more C02 lasers, one or more lasers of diodes, an addressable arrangement of lasers or one or more LEDs, for example. The output 41 of the light source 40 is forced to form the desired image by manipulation of the light source or by programming a laser array, all known in the art. The color absorbed in the layer 62 is immediately led to the thermochromic layer 63 and causes selected portions of the layer 63 to change color or otherwise change their visual appearance to produce the desired image. The phrase "changing the visual appearance" means a change of color, darkness or other visually detectable change in appearance. Figures IA and IB illustrate the "back-side dialing" mode of the present invention, wherein the laser radiation (or other light source) 41 is applied across the rear or rear (unobserved) surface 61a of the means 60. The means 60 includes three layers: a front layer 63, a back layer 61, and an intermediate, light-absorbing light layer 62. Figure IB shows the eye of an observer 65 viewing the resulting mark 68. The light it is absorbed by an inexpensive light absorbing layer 62, which absorbs a broad spectrum of light, including NIR, and also absorbs visible light. That material can be much more readily available as an ink and much cheaper (approximately 80% cheaper) than the shortband NIR absorbers - an example is carbon black.

In addition, it can be activated by light sources of a wider wavelength range, including visible light. Adjacent to the absorbent layer 62 is a front thermochromic layer 63 that performs two functions: it changes color or otherwise changes in visual appearance in response to the generated heat (thermochromic) when the applied light radiation is absorbed by the absorbing layer of light 62, and conducted to the thermochromic layer 63, and preferably obscures the light absorbing layer 62 so that the layer 62 has reduced visibility or is not visible to the naked eye when the means are observed from the front surface as shown in FIG. Figure IB. The function of color change (or visual appearance) can be achieved by any thermochromic chemistry, such as those used in standard direct thermal media (for example, a coating consisting of dye and color activator). A further example is a coating comprising a color activator, a color developer and a sensitizer. In this way, a massively available product is already available at low cost. The dimming function can be further enhanced by adding a diffraction material to the thermochromic face layer 63. For example, Ti02 particles of an appropriate size are very effective in providing dimming in a thin layer. The additional benefit of a light diffracting material in a front layer of change of Color 63 is that light that is not absorbed during passage through the absorbent layer can be reflected or diffracted backwards by the light diffracting material in the front layer (as shown in Figures 9A-9B and 10A- 10F as described below), thereby passing through the absorption layer 62 again for an additional opportunity to be absorbed. One restriction of this design is that any substrate used as the back layer 61 must be translucent, to allow light to reach the absorbent layer 62. The word "translucent" as used herein and in the claims, means transparent to, or sufficiently transmitting. of the beam of the light output to form the desired image. This can be a polymer or, as, for example and without limitation, polyethylene, polypropylene and polyester. To achieve better sensitivity, the peak temperature in the color change layer 63, for a given laser energy should be maximized. This can be done by: - using a heat conducting layer and extremely thin light absorber 62 (an alternative to carbon black is graphite or carbon nanotubes having better conductivity). - using a thin layer of color change (thermochromic) 63, again with good thermal conductivity, to ensure that the heat reaches the top or visible front surface of the layer and the visibility of the brand is maximum. - using an absorbent layer 62 with less than 100% absorption, so that the absorption distribution of the absorbent layer is diverted towards the surface near the color change layer (thermochromic) 63. - if used a top coating layer (not shown) on top of the color change layer 63 (for example, to provide resistance to solvents), this layer should be as thin as possible. It is important to note that the "back side" laser marking of media 60, shown in Figures IA and IB, can be used in a variety of printing, labeling and packaging applications.

Marking by the "Front Side" of the Media of Three Layers Figures 2A and 2B illustrate direct laser marking through the front side of three layer laminate means 160 according to the present invention. This mode can be used in applications such as marking, packaging or other printing applications. As shown in the Figures 2A and 2B, the laser beam (or other high intensity light beam, a laser diode array) 341 is emitted from a light source 140 and is applied to the means 160 which they have a front face 163b, a rear face 161a and having three separate layers, the front layer 163, the back layer 161 and an inexpensive medium or central heat absorbing layer 162. This time, the marking on the front is used for marking the front layer 163, but the broadband absorber 162 (eg, carbon black) is retained, with its low cost advantage. This time, to prevent the absorbent layer 162 from being visible by the observer 165 seen on the resulting mark 168 on the front surface 163b (as shown in Figure 2B), the super-opaque thermochromic front layer 163 is rendered opaque in FIG. a visible range, but allowing a light through it to the activation wavelength, typically 700nm-1600nm. This can be achieved by incorporating particles of a dielectric material whose refractive index is different, so that the matrix of the thermochromic front layer 163 is smaller at the excitation wavelength but larger in the visible wavelength range. To maximize sensitivity in this case, a high absorption coefficient is required in the absorbent layer 162 to maximize the proximity of the heat generated to the thermochromic layer 163. Minimizing the thickness of the thermochromic layer 163 and any coating layer (not shown) Sensitivity will also be maximized by minimizing heat propagation.

The dialing systems shown in Figures IA, IB, 2A and 2B are "indirect" light marking systems or techniques in the sense that the exit light is first absorbed by the light absorbing layer (62, 162), converted to heat by the light absorbing layer (62, 162), and then thermally driven to the thermochromic layer (63, 163) to create the desired mark. Figures 3A and 3B illustrate the multilayer means 60, as shown in Figures IA and IB, including optional darkening means 80. As shown in Figures 3A, the substrate 61 has a back surface 61a, as described above. The light absorbing layer 62 is shown in Figure 3A as being supported on the surface of the substrate 61. As shown in Figure 3A, the darkening means 180 is a layer of material 181 that is located between the light absorbing layer 62. and the thermochromic layer 63. The purpose of the darkening means 80 is to reduce the visibility of the light absorbing layer 62 with the naked eye. The layer 181 can be formed of one or more materials selected from the group consisting of Ti02 particles, calcium carbonate particles, wax powder and a polymeric matrix in which gas bubbles were formed. The darkening layer 181 is a microscopic mixture of at least one translucent material together with one or more materials selected from the identified group above, provided that the translucent material has a different refractive index than the materials in the group. The darkening layer 181 should preferably be thin and have a high thermal conductivity to achieve the best thermal contact between the light absorbing layer 62 and the thermochromic layer 63. Alternatively, the darkening means 80 may comprise a variable darkening layer. 181, where the thermochromic effect is achieved through the variation of the darkening degree (ie, without using leuco dyes). For example, the layer 181 may be translucent in the absence of applied heat, and the applied heat conducted from the light absorbing layer 62 causes it to become opaque, for example, by the formation of gas bubbles within a polymeric matrix, obscuring therefore to the absorbent layer. Alternatively, the darkening layer 181 may have an opaque state in the absence of heat, and the heat conducted from the light absorbing layer 62 to the translucent darkening layer 181, for example, by melting a wax powder in a mixture of gas / wax, thereby allowing the dark absorbent layer 62 to be observed in the exposed areas. Figure 3B illustrates an alternative embodiment of the invention, wherein the darkening means 185 does not form a separate layer, but is included in the layer Thermochromic 63. The alternative darkening means 185 performs substantially the same function as the darkening means 180 as shown in Figure 3A "The darkening means 185 is preferably located as close as possible to the light absorbing layer 62, but in any case they are placed between the light absorbing layer 62 and the front visible surface 63b of the thermochromic layer 63. The darkening means 80 and / or 85 can also be applied to the means 160 illustrated in Figures 2A and 2B of the same shape as illustrated in Figures 3A and 3B when applied to the media 60. The darkening means 80 and / or 85, as used in the "front marking" technique of Figures 2A, 2B, are translucent to the wavelength of the output beam of the light source. Figure 4 is a schematic illustration of the means 60, as shown in Figures IA and IB, where the light absorbing layer 62m is included in the layer of the substrate 61. The light absorbing layer 61m is preferably carbon black, which was extruded into the plastic substrate 61. The preferred carbon black layer can be as thin as possible and as dense as possible to ensure that sufficient light output energy is converted to heat and efficiently conducted to the thermochromic layer 63. The The thermochromic layer is preferably applied to the substrate 61 by flexographic printing. As an alternative to the inclusion of the light absorbing layer in the substrate 61, as shown in Figure 4, the light absorbing layer 62 or 162 (Figures IA, IB, 2A and 2B) can be applied to the substrate by printing Flexographic and thermochromic layer 63 or 163 then applied to the light absorbing layer 62 or 162 by flexographic printing to produce the three distinct layers shown in Figures IA, IB, 2A, and 2B. Figure 5A is a schematic representation of the means 60, shown in Figures 1A and IB, where an optional reflector coating 64 has been applied to the front surface 63b of the thermochromic layer 63. The coating 64 is supported by the layer 63 or is adjacent to the front surface 63b of the layer 63. The purpose of the reflective layer 64 is to reflect the light back into the light absorbing layer 62, which is not absorbed by the layer 62 when the first light beam of output through layer 62. Figure 5B is a schematic representation of the means 60 of Figures IA and IB illustrating an optional protective coating 65 which is preferably a clear protective coating of, for example, varnish, which protects the thermochromic layer 63.

Use of the Multilayer Sheet for Labeling Products The prior art typically requires labeling machines and separate label designs for each price or "PLU" number query. PLU numbers are by retailers to facilitate quick handling and change exact product prices. For example, to apply labels denoting "small" or "medium" or "large" channel designations for apples, the prior art typically requires three separate labeling machines, three separate label designs, and three label inventories. If a packer packages more than one brand, the configuration of the equipment is doubled. This label application equipment is expensive, requires maintenance, and requires a significant amount of physical space on the sizer and therefore restricts where the packaging operation can fall to further pack the product. The present invention provides the same labeling in the previous example with only a labeling machine and a label design. The most widely used type of product labeling machine uses a rotating bellows applicator. It is advantageous to minimize any modifications to existing product labeling machines by creating a system for applying variable coding "on the fly". Similarly, the speed of operation of the machines Existing labellers must be maintained. The present invention solves the problem of applying variable encoded information "on the fly". No significant modification of the existing rotating bellows applicators is required. No reduction in labeling speed is required. In a preferred embodiment, the invention uses one or more laser output and laser to pass through the back of the opposite surface of the label (on which the adhesive layer is located), through the substrate of the label, and to cause an image to be formed on the front or visible surface of the label. The prior art includes several attempts to meet the growing demand for a wide variety of labels and variable information. A prior art method (US Pat. No. 6,179,030) places product labeling machines downstream of the sizing equipment, so that all labels indicate the same product size. Of course, this method involves the expense of modifying the transport equipment and is limited to the application of size information. Another attempted solution of the prior art has been to apply variable encoded information to the front or visible surface of the label before the label is transferred to the tip of a bellows (see patent American 6,257,294). The difficulty with that attempted solution is that the label being printed is forced and folded when it is transferred from the label strip to the tip of the bellows. A complex arrangement of airflow is provided to try to control the label and to dry the ink. The applicants here are aware that the devices and the applicants' understanding is that the method has not been commercially accepted. Another procedure is possibly to apply variable information to the labels upstream of the point at which the labels are transferred to the rotating bellows. The difficulty with this method is that the requirement of sensors and timing devices increases the cost significantly. For example, to detect variable information during 24 points of the product, and to be able to apply a newly printed label to a piece of product ie 24"slots" that both require the use of a large amount of memory and timing and synchronization circuits complexes to ensure that the appropriate information is applied to the appropriate element of the product; all at prohibitive costs. The present invention overcomes the difficulties mentioned above by the attempts of the prior art. The present invention avoids the reconfiguration of the dimensioning and transport equipment required in the US Patent 6,179,030. The present invention, in sharp contrast to US Pat. No. 6,257,294, applies the variable encoded information to the upper label after the label is transferred to the tip of rotating bellows, and avoids the problems inherent in the solution attempted by the prior art. . In addition, the present invention also contrasts with US Patent 6,257,294, avoiding the use of sprayed ink and the required drying time using one or more laser beams that react instantaneously with the novel label sheet of the invention. The present invention also avoids the use of expensive timing and detection circuits by applying the variable encoded information immediately before the label is applied to the appropriate product element. The label sheet of the present invention is particularly designed to be used in conjunction with the system described in U.S. Patent Application Serial No. 11 / 069,330, filed March 1, 2005, and entitled "Method and Apparatus for Applying Coded Labels of Variable Way to Elements of Products ", request which is incorporated here as reference, as it was exposed in its entirety (the application? 330). The pertinent aspects of the application 330 are included below to facilitate the explanation of the present invention. One more description Complete of the labeling machinery is contained in the application? 330 and refers to it here. The use of rotating bellows applicators, as shown in the application? 330, has become the standard in the product labeling industry. Any novelty of the use of a rotating bellows applicator head would require a significant investment in the new labeling apparatus. The present invention requires only minor modifications to standard rotary bellows applicators. The present invention does not use ink which requires a relatively long drying time. The present invention applies the information while the label is in motion, but in a relatively stable position, after the tip of a bellows has been transferred, maximizing the clarity of the image. The present invention is capable of forming images at a commensurable speed with maximum speeds of existing rotating bellows label applicators. Figures 6 and 7 of the present are reproduced from the application 330. As shown in Figures 6 and 7, a label cassette 10 feeds labels one at a time on the tips of the bellows 21-24 of the rotating bellows applicator 20, as is known in the art. Laser encoder means 40 (which could be a laser, laser array, LED or other high light source) intensity) are used to produce human-readable or variable codes on a label of a thin-film product sensitive to pressure 160 (as shown in Figure 6) just prior to the application of the label to a element of a product. The codes are produced in response to the detection means 90 which detect variables such as size or color, as described more fully in the application 330. The code is preferably produced by labeling the label 60 from the back side through the the adhesive and film layers, as shown in Figures IA and IB generally, as described in more detail below. Figure 8 illustrates schematically the actual environment in which the multilayer laminated label 160 of the present invention is marked. The label 160 of Figures 8, 9A and 9B is the same label 60 of Figures IA and IB, except that the label 160 includes a fourth layer of translucent adhesive 169 and is rotated 180 ° of its orientation in Figures IA and IB . The front or visible surface 163b is on the right side of the means 160 of Figures 9A and 9B, while the front or visible surface 163b is on the left side of the means 60 in Figures 1A and IB. The multilayer label 160 is shown in Figure 8 as being supported on the tip 123a of the bellows 123. The label 160 is shown as forming a curved surface, due to the curved or dome shape of the surface of the tip of the bellows 123a. The bellows 123 rotate about the axis of rotation 129 in the direction of arrow 128. The label 160, shown in Figures 6-8 but best shown in Figure 8, includes a translucent plastic substrate 161, a light absorbing layer. inexpensive (preferably carbon black 162) and a thermochromic layer 163. The adhesive 169 is supported by the back surface 161a of the plastic substrate 161 and is used to adhere the label 160 to the product element to which the label is to be applied. The laser encoding means (or other high intensity light source) 140 are schematically illustrated in an output beam 141. It should be understood that the laser encoding means 140 may preferably be any arrangement of semiconductor diode lasers in addressable or solid state. they can be a simple C02 laser whose output beam can be measured by galvanometric means or others known in the art. The bellows 123, as illustrated in Figures 6-8, move between two indexing stations in which the bellows stop momentarily at slow label application speeds; The bellows may not stop at the speed of application of higher labels. According to the present invention and as described With further detail, it is advantageous to mark the label 160 when the bellows 123 move at a relatively stable speed between two of their indexed positions. Figures 9A and 9B are schematic representations of the methodology used in the label marking illustrated in Figure 8. As shown in Figure 9A, the laser output beam 141 has penetrated the translucent adhesive layer 169 and the translucent substrate 161 and is close to entering the absorbent layer of carbon black 162. The thickness of the arrow representing the laser output beam 141 represents the energy contained in the output beam as it begins to enter the absorbent layer 162. As shown in Figure 9B, the laser beam 141 has passed through the absorbent light layer 162, has transferred a greater portion of its energy to the light absorbing layer 162 and the remnants of the beam 141 have been separated into a reflected 141a fragment which is reflected backward through the substrate 161 and the adhesive layer 169. A second fragment 141b simply passes through the thermochromic layer 163 and is lost. The reduced width of the arrows 141a and 141b represents the beam fragments of approximately 70% of the energy of the beam 141 was absorbed by the light absorbing layer 162 and conducted immediately to the thermochromic layer 163 as shown by a portion 163m of the thermochromic layer 163 which has changed color (or otherwise changed its visual appearance) to form a portion of the mark according to the invention. Figures 10A to 10F illustrate a further aspect of the invention where the laser output beam 241 is shown entering a multilayer laminated label 260. As shown in 10B, the output beam has passed through the translucent adhesive layer 269 and the translucent plastic substrate 261 and is close to entering the light absorbing layer 262. As shown in Figure 10C, the laser beam 241 is shown as it passes through the light absorbing layer 262, giving the majority of energy to the light absorbing layer and retaining about 30% of its energy when it enters the thermochromic layer 263. Figure 10D illustrates that the laser beam 241 is reflected backwards by the reflecting particles 267 that are included in the thermochromic layer 263. The reflected laser beam is shown in Figure 10D as if it began to pass through the light absorbing layer 262 a second time. Figure 10E illustrates that the laser beam 241 has passed through the light absorbing layer 262 a second time and has provided a greater portion of its energy remnant, but has contributed to the additional light energy to the light absorbing layer 262. The light energy of the laser beam 241 passes through the light absorbing layer twice converted immediately into heat energy and conducted to the thermochromic layer 263, which is in thermal contact with the light absorbing layer 262, and causes a portion 263m of the thermochromic layer 263 to change color (or otherwise change its visual appearance). As an alternative to including diffracting material in the thermochromic layer 263, as illustrated in Figures 10A-10F, a reflective coating may be applied to the front surface 263b of the thermochromic layer 263, which would cause the remnants of the laser beam to be will reflect backward through the light absorbing layer 262 where a larger portion of the remaining energy of the laser output beam is transferred to the light absorbing layer 262. Figures HA and 11B are illustrations of what a typical brand would look like. produced by the invention; Figure HA shows typical dimensions and Figure 11B illustrates the actual size of a typical brand 68.

Direct Laser Marking of Two-Layer Media In addition to the above embodiments, the invention also includes direct laser marking using two-layer media having a plastic substrate layer and a thermochromic layer. As shown schematically in Figure 12, a two-layered medium 360 includes a substrate 361 and a thermochromic layer 363. The back or rear side of the means 360 is the back or opposite side 361a of the substrate 361. The visible front surface of the means 360 shown in Figure 12 is the surface 363b which is the front surface of the thermochromic layer 363.

Requirements for Laminated Label Material for Two-Layer Media The following is a general description of the requirements of the laminated label for a two-layer label to achieve labels for fruits and vegetables of acceptable quality. The laminated substrate 361 is preferably a Low Density Polyethylene (LDPE) film of approximately 40 μm in thickness. The media and its components must comply with government regulations related to the health and food safety aspects that govern the use of similar products. Substrate 361 must be free of any slip agents or other additives with the exception of minimum amounts of natural silica antiblocking agent and polymer process adjuvants (not present in the surface layer of the finished film), also a white masterbatch in the case of white film products. The film or substrate of tag 361 is an extruded film with a white master batch present. The white masterbatch typically consists of Ti02, Lithopone, Kaolin Clay or other suitable bleach.

Exemplary Methods There is no method to achieve an acceptable label on a PE label. However, there are several main components that must be refined or directed to create the desired result. Table 1 presents five exemplary methods and relative major components that achieve acceptable marks on PE labels. After the table, a detailed description of the different components for each example is defined and outlined.

Table 1. The following table gives several methods that were developed to achieve a readable mark with the given laser source. Some of the most important features required to achieve the brand are shown.

I. Main Components for Achievement © Láse-r i.l. Lasos Energy Density - The energy density (e) is a measure of how much power is necessary to create a mark over a given area in a specific time interval and is estimated based on the following equations: P - t e = v - d, where P- laser power required to produce a mark (W), t- time required to produce the mark (s), A- area that is marked (cm2), v- velocity of a sample moving along a stationary laser or the laser speed when moving over a sample ( cm / s), and di-diameter the size of the laser point (cm). For example, the energy density required to create a dark readable mark with a C02 laser and a galvanometer on a LDPE label coated with a thermal chromatic material through the back sides as follows: P W e - = 0.69J / cm 2 v -d, 500cm / s - 0.023cm 1. 2. Laser Wavelength: The wavelength depends on the laser source that is selected. The two laser sources selected were a C02 and diode laser. Typical laser dispensers are Synrad, Inc., Universal Laser Systems, Inc., JDS Uniphase Corp., Coherent, Inc., Sacher Lasertechnik GmbH, etc. The C02 lasers have a wavelength of between about 9,200 and 10,900 nm (lasers are typically specified at 10600 nm). Diode lasers come in a variety of wavelengths (300 to 2300 nm); however, for this application the range of The most appropriate wavelength is between 800 and 1600 nm.

This range is beyond the visible range and within the range commonly provided by inexpensive diode lasers. 1. 3. Subscription Material of the Subsistence day Label: The material for filling or loading the substrate 361 is selected to achieve two basic functions: to present a suitable background to achieve a high contrast with the laser mark and to allow a high transmittance (or low absorption) of the laser wavelength selected. In other words, the sheet must appear visible to the laser and white (if the mark is black) to the human eye. The filling or loading material for methods 1 and 2 (see Table 1) is a white masterbatch containing Ti02 at approximately 7.5%. Ti02 has a particle size of about 200 to 220 nm. For methods 3 to 4, no masterbatch was blown into the substrate material of tag 361 (typically a polyethylene). Therefore, the material is clear to the human eye and is translucent with respect to the wavelength product produced by a diode laser. For method 5, the NIR absorber that was of carbon black was blown into a thin layer of the substrate side of the label. l. . Coating: The coating 363 used in this mode was a coating used on paper and / or film for direct thermal printing. These coatings typically contain fillers such as kaolin clay to provide a surface for the print head to run; however, this is not necessary for this application. Typically, the thermal layer should contain 3 key components - a color former, a color developer and a sensitizer. The thermal energy of a laser or a laser interaction with an absorber causes the sensitizer to melt allowing the color former and developer to mark an image. The companies that supply this type of product are Appleton (www.appletonideas.com) Ciba Specialty Chemicals (www.cibasc.com), Smith and McLaurin LTD (www.smcl.co.uk), etc. 1. 5. Lasor-sensitive Absorbent: NIR absorbents were mainly used with the diode laser source to act as a collector to attract the laser energy. This allows the media to warm to a temperature required to create a color change. Absorbents can typically be purchased from the following sources: Exciton (IRA 980B), H.W. Sands (SDA9811), etc. 2. Other Specifications of the Label Material There are two different formulation systems to consider for the integration of a laser-sensitive agent in or on the base label material and include: A. A modified film where the agent is incorporated into the polymer, and B. a surface coating containing the agent that can be applied to the surface of the film as a liquid. The key aspects for the development of this material are the following: 2. 1 Safety: The material must not have more than one irritant smaller than a liquid. The film coated and printed with the laser, which includes the laser activated area, must be acceptable for indirect contact with the food and should not be toxic when ingested by very small amounts. 2. 2. Environmental problems: The material and the resulting mark must be rough, splash-proof and durable to withstand typical packing environments (ie, ambient temperatures of 0 to 45 ° C, relative to humidity). up to 98% without condensing). It must also be able to withstand caustic environments of pH 7-11.5. 2. 3. Working Capacity: The coated or filled material must not in any way affect the ability of the finished labels to stick, adhere or conform to the surface of the fruit that is normally labeled. 2. 4. Material Activated by Laser: It is necessary that the reactive material does not emit toxic smoke or other residues or leave any toxic residue on the substrate. It is therefore preferred that the laser-sensitive agent be placed in the film as a filler or filler (mixed) rather than applied as a coating. 2. 4.1. Loading or Filling Characteristics - It is essential that the sensitive filler or filler material is mixed into the base film material. The resulting construction can maintain all the characteristics and central properties of the material of the current label and still reacts with the laser energy applied to any of its surfaces at the specified energy density. 2. 4.2. Coating Characteristics - The following are the main aspects related to the formulation and application of a laser-activated coating: 2. 4.2.1. Formulation - Inline flexographic printing is the preferred coating process. Other processes to be considered if the flexographic printing is inadequate are the Rotating Serigraph, Engraving, etc. The preferred coating should be water based. It should have a shelf life of 6 months for a concentrate. 2.4.2.2. Off-line coating - Off-line coating before conversion should be considered as an alternative if in-line coating is not possible. 2.4.2.3. White, black dial - white, black dial, produces sufficient contrast levels to give a good scanning ability when printing a barcode. 2.4.2.4. Flexibility - the coating must remain flexible after curing. 2.4.2.5. Overprinted - the coating must be overprintable with flexo-standard inks, without loss of gloss. 2.4.2.6. Sure - the coating must be secure, well bonded to the substrate and reasonably resistant to abrasion / scratching. 2.4.2.7 Storage Stability - the coating must be stable as a component of a rolled product when stored under conditions normally suitable for rolled products of adhesives sensitive to pressure. 2.4.2.8 Printing Stability - the coating must be stable when printed on the surface of a label and exposed to UV light and moisture. 2.4.2.9 Residues - the coating is for marking with little or no smoke or residue, all of which must be free of toxins. 2. 5 Characteristics of the Marking System The marking system must be capable of printing at 12 labels / sec (720 labels / min) which in a label applicator is equal to a linear speed of 1.27 m / sec. The label is supported on bellows on the adhesive side presented to the laser system (ie, that the laser must mark through the adhesive side of the label). The bellows moves close to constant speed when indexed between the labeling stations. Therefore, the material must react with the laser energy and mark this example in less than the specified time. The specifications of typical laser systems for C02 laser systems and diodes are outlined in the following sections. 2. 5.1. C02 Laser System with Head Two Axes Exploration - The following table is a list of laser system specifications: Parameters Value Laser Type C02 Wavelength 10.6 μm Power Output ~ 10 Watts or more Spot Size 230 μm Head Speed of 5,000 mm / sec Typical Scan Typical Energy Density 0.69 J / cm2 The most important feature is to be able to mark the example illustrated in Figures HA and 11B while the laser is focused. The depth of field for a typical C02 laser is approximately 2 mm. The depth of the field parameter can be limiting. This is mainly because the laser is trying to mark a target on the bellows when it rotates around an axis. By improving the depth of field, it is possible that the scanning spectrum follows the label thus allowing the laser to focus on the target for a longer period of time. 2. 5.2. Diode Laser System - The next Table is a typical list of laser system specifications: ametros Value Type of Laser Diode Wavelength 808 nm, 830 nm, 980 nm, etc, Power Output 24 Watts / cm (300 dpi) Point Size 80 μm Separation of the Emitter 80 μm (300 dpi) Typical Energy Density 0.20 J / cm2 (300 dpi) The most important feature is to be able to mark the example shown in Figures HA and 11B when the labeling system is operating at 720 fruits per minute. Another important consideration for this laser system is the energy density which for the parameters of the previous system is approximately 0.20 J / cm2.

Use of Reflective Elements with Direct Thermal Coating The following method describes how it is possible to use reflective coatings, surfaces or particles to optimize the laser energy available for variable encoded laminated labels using the present invention for "on the fly" application for fresh products. . The reflective materials are described in part previously in conjunction with Figures 5A and 10A-10F. This can be achieved with all types of lasers specifically with lasers based on C02 and diodes. By optimally selecting the material and the finished material that contains the laminated label, the laser energy can be directed back to the label to increase the exposure time. Therefore the total energy density at which the label is exposed improves and the resulting mark produced by the laser is dark or a similar mark can be achieved at a higher speed. When the light interacts with a given material, it will be reflected, transmitted or absorbed. The thermochromic material applied to the face of the label has been selected to absorb the laser energy. Even when 50% or more of the laser energy can be lost (ie, transmitted or reflected). It is therefore preferable to design the surface of the label carrier so that it reflects as much laser energy as possible back to the face of the label. Since lasers can be selected with different wavelengths, this material must be selected carefully for the desired laser.

Example 1: Scenario 1 Laser: C02 with 10 Watts with 2D scanning head Coating: Direct Thermal (Typically found on paper labels used in Direct Thermal Printers) Sheet: LDPE White Writing Speed: 5000 mm / s Power: 55 % Label Support Material: Black rubber The power increased in increments of 5% until the resulting mark was completely marked. For this step the power level was 55%.

Scenario 2 Laser: C02 of 10 Watts with 2D scanning head Coating: Direct Thermal (Typically found on paper labels used in Direct Thermal Printers) Sheet: LDPE White Writing Speed: 5000 mm / s Power: 45% Label Support: Brushed Aluminum Again the power increased in increments 5% until the resulting mark was completely marked. For this step the energy level was 45%.

There was a decrease of 18% in the power or on the contrary an increase in the total performance.

Example 2: Scenario 1 Laser: Single beam laser of 980 nm 0.20 Watts Coating: Direct Thermal (Typically found on paper labels used in Thermal Printers Direct) with NIR absorbent mixed in the direct thermal layer Sheet: LDPE Clear Writing Speed: 40 cm / s Power: Watts Label Support Material: Black rubber The writing speed was increased in increments of 5 cm / s until the resulting mark was completely marked (ie the width of the line equal to the total width of the semi-maximal laser parameter of -80 μm).

For this scenario, the writing speed was 40 cm / s.

Scenario 2 Laser: Single beam laser of 980 nm of 0.20 Watts Coating: Direct Thermal (Typically found on paper labels used in Direct Thermal Printers) with NIR absorber mixed in the direct thermal layer Sheet: LDPE Clear Writing Speed: 40 cm / s Power: Watts Label Support Material : Brushed Aluminum Again the writing speed was increased in increments of 5 cm / s until the resulting mark was completely marked (ie the width of the line equal to the total width of the semi-maximum laser parameter of -80 μm). For this scenario the Writing speed was 50 cm / s. There was an 18% increase in writing speed, that is, a total increase in performance. The above description of the invention has been presented for purposes of illustration and description and is not intended to be exhaustive or to limit the invention to the precise form described. Modifications and variations are possible in light of the previous teachings. The modalities were chosen and described to better explain the principles of the invention and their practical applications to thereby allow those skilled in the art to better use the invention in various modalities and with various modifications. suitable for the particular use contemplated. The scope of the invention will be defined by the following claims. It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims (1)

1. CLAIMS Having described the invention as above, the content of the following claims is claimed as property. 1. Multilayer laminated media on which readable information can be applied by a machine or a human on a visible front surface of the media by the output of a high intensity light source, characterized in that they comprise: a media substrate, having the substrate rear and front surfaces, a light absorbent layer, the layer adapted to absorb light from the output of the high intensity light source and to convert the absorbed light into heat, and a thermochromic layer in thermal contact with the absorbent layer of light, the thermochromic layer forming the visible front surface of the media, where portions of the thermochromic layer change in visual appearance in response to application of the high density light agent output in the light absorbing layer, and heat conduction converted from the light absorbed by the light-absorbing layer to the thermochromic layer. The apparatus according to claim 1, characterized in that it also comprises darkening means between the light absorbing layer and the visible front surface of the thermochromic layer, which reduces the visibility of the light absorbing layer with the naked eye. The apparatus according to claim 2, characterized in that the darkening means is a layer between the light absorbing layer and the thermochromic layer. The apparatus according to claim 2, characterized in that the darkening means are included in the thermochromic layer. The apparatus according to claim 2, characterized in that the darkening means comprise particles for diffracting the light and providing the darkening of the light absorbing layer. 6. The apparatus in accordance with the claim 2, characterized in that the darkening means are formed of one or more materials selected from the group consisting of Ti02 particles, calcium carbonate particles, wax powder and a polymeric matrix in which gas bubbles are formed. . The apparatus according to claim 2, characterized in that the darkening means comprise a variable darkening layer which becomes opaque in selected portions when it absorbs heat. 8. The apparatus in accordance with the claim 2, characterized in that the darkening means comprise a variable darkening layer which becomes transparent in selected portions when it absorbs heat. The apparatus according to any of claims 1-8, characterized in that the light absorbing layer absorbs light in the visible wavelength and NIR (near infrared) to light ranges. 10. The apparatus according to any of claims 1-9, characterized in that the light absorbing layer is selected from the group consisting of carbon black, graphite nanotubes and carbon. 11. The apparatus according to any of claims 1-10, characterized in that the light absorbing layer is an NIR absorber. The apparatus according to any of claims 1-11, characterized in that the substrate is translucent plastic and the output of the high intensity light source passes through the back surface of the translucent substrate before entering the absorbent layer. of light. The apparatus according to any of claims 1-11, characterized in that the output of the high intensity light source passes through the visible front surface of the media and the thermochromic layer before entering the absorbent layer of the light source. light. 14. The apparatus according to claim 13, characterized in that it has darkening means, and wherein the darkening means are translucent at the output wavelength of the light source. 15. The apparatus according to any of claims 1-14, characterized in that the high intensity light source comprises an arrangement of semiconductor diodes in solid state addressable. 16. The apparatus according to claim 1, characterized in that the high intensity light source is one or more LEDs. 17. The apparatus according to claim 1, characterized in that the high intensity light source comprises a single C02 laser. 18. The apparatus in accordance with the claim 1, characterized in that the plastic substrate is selected from the group consisting of polyethylene, polypropylene and polyester. 19. The apparatus according to claim 1, characterized in that the thermochromic layer comprises a coating of leuco dye and color activator. The apparatus according to claim 1, characterized in that the thermochromic layer comprises a color-forming coating, color developer and sensitizer. 21. The apparatus according to claim 1, characterized in that the light absorbing layer has less than 100% absorption, so that the distribution of absorption through the light absorbing layer is diverted towards the thermochromic layer. 22. The apparatus according to claim 1, characterized in that it further comprises reflector coating means adjacent to the front surface of the thermochromic layer to reflect light from the high intensity light source back into the light absorbing layer. 23. The apparatus according to claim 1, characterized in that it further comprises reflecting particles to reflect light from the high intensity light source back into the light absorbing layer. 24. The apparatus according to claim 1, characterized in that it comprises a translucent layer of adhesive supported by the back surface of the plastic substrate. 25. The apparatus in accordance with the claim 1, characterized in that it also comprises a protective coating, clear, applied to the visible, frontal surface of the thermochromic layer. 26. The apparatus according to claim 1, characterized in that the light-absorbing layer is included in the substrate. 27. The apparatus according to claim 26, characterized in that the thermochromic layer is applied to the substrate by flexographic printing. 28. The apparatus in accordance with the claim 1, characterized in that the light absorbing layer is applied to the substrate by flexographic printing. 29. The apparatus according to claim 28, characterized in that the thermochromic layer is applied to the light absorbing layer by flexographic printing. 30. A multi-layered label for use in an apparatus for automatically applying labels to individual product elements, where each label has a visible front surface of a back surface and the variable encoded information is applied to the label in human readable form or a machine, where a rotating bellows applicator is used to transfer individual labels from the label support strip onto the tip of a single bellows and subsequently onto individual product elements, where the detection means detect a variable characteristic of the product element , where the output of the high intensity light source is used to apply the detected variable feature to the back surface of each of the labels while each label is at the tip of a bellows, characterized by: a plastic label substrate, the substrate having rear and front surfaces and the output of the high intensity light source being translucent, a light absorbing layer supported by or included within the front surface of the plastic label substrate, the layer adapted to absorb light from the output of the high intensity light source and to convert absorbed light into heat, and a thermochromic layer in thermal contact with a light absorbent layer, the thermochromic layer forming the front, visible surface of the label, where portions of the thermochromic layer change the visual appearance in response to the application of the high intensity light source output through the substrate in the light absorbing layer, and the heat conduction converted from the light absorbed by the heat absorbing layer to the thermochromic layer. 31. The apparatus according to claim 30, characterized in that it further comprises a translucent layer of adhesive supported on the back surface of the plastic substrate. 32. The apparatus according to claim 30, characterized in that the high intensity light source comprises a semiconductor diode array. in solid state, addressable. 33. The apparatus according to claim 30, characterized in that the light absorbing layer is selected from the group consisting of carbon black, graphite nanotubes and carbon. 34. The apparatus according to claim 30, characterized in that the plastic substrate is selected from the group consisting of polyethylene, polypropylene and polyester. 35. The apparatus according to claim 30, characterized in that the thermochromic layer comprises a coating that includes a color former, color developer and sensitizer. 36. The apparatus according to claim 30, characterized in that the thermochromic layer further comprises particles for diffracting the light and providing dimming of the light absorbing layer. 37. The apparatus according to claim 30, characterized in that the light absorbing layer has less than 100% absorption, so that the distribution of the absorption through the light absorbing layer is diverted towards the thermochromic layer. 38. The apparatus according to claim 30, characterized in that the light absorbing layer is a near infrared absorber. 39. The apparatus according to claim 30, characterized in that it further comprises means of darkening between the light-absorbing layer and the visible, front surface of the thermochromic layer, which reduces the visibility of the light-absorbing layer with the naked eye. 40. The apparatus according to claim 30, characterized in that it also comprises a protective coating, clear, applied to the visible, frontal surface of the thermochromic layer. 41. The apparatus according to claim 30, characterized in that the absorbent layer is included in the substrate and the thermochromic layer is applied to the substrate by flexographic printing. 42. In an automatic labeling machine used to apply labels to products, wherein a label applicator having a plurality of bellows supported on a rotating applicator head is used to transfer individual labels of a label carrying strip one onto the individual bellows strip and subsequently on individual product elements, each label having a visible front surface and a back surface, the improvement characterized in that it comprises: a plurality of plastic labels supported by the support strip, wherein each of the plastic labels includes a plurality of layers, including a translucent plastic substrate, a translucent layer of adhesive supported by the back or reverse surface of the substrate, a light absorbing layer adjacent to the front surface of the substrate, and a thermochromic layer adjacent to the front surface of and in thermal contact with the heat absorbing layer, detection means for detecting at least one variable characteristic of each of the individual product elements, laser encoder means which operate in response to the detection means to produce a human-readable code or a machine, variable, representative of the variable characteristics on each individual label, where the label is supported on the tip of the bellows and before the application of the individual label to the particular element of a product for which the characteristic was detected variable, where the laser coding means are positioned so that the outlet is directed towards the rear surface of the label transferred on the tip of a single bellows, where the laser outlet passes through the adhesive layer and through the plastic substrate of each label and is partially absorbed by the light absorbing layer, portions of the thermochromic layer change color in response to the application of the output of the laser coding media through the substrate towards the light absorbing layer, and the conduction of the heat absorbed by the layer that absorbs light towards the thermochromic layer. 43. The apparatus according to claim 42, characterized in that the laser encoder means comprises a semiconductor array in addressable solid state. 44. The apparatus according to claim 42, characterized in that the heat absorbing layer is selected from the group consisting of carbon black, graphite nanotubes and carbon. 45. The apparatus according to claim 42, characterized in that the plastic substrate is selected from the group consisting of polyethylene, polypropylene and polyester. 46. The apparatus according to claim 42, characterized in that the thermochromic layer comprises a coating that includes a color former, color developer and sensitizer. 47. The apparatus according to claim 42, characterized in that the thermochromic layer further comprises particles for diffracting light and provide dimming of the light absorbing layer. 48. The apparatus according to claim 42, characterized in that the light absorbing layer has less than 100% absorption, so that the distribution of the absorption through the light absorbing layer is diverted towards the thermochromic layer. 49. The apparatus according to claim 42, characterized in that the thermochromic layer has a front surface which is the visible surface of the label, and in that it also comprises a reflector coating supported by the front surface of the thermochromic layer to make the output of the laser encoder means is reflected back to the light absorbing layer. 50. The apparatus according to claim 42, characterized in that the laser coding means is a single C02 laser. 51. A method for automatically applying labels to individual product elements, wherein each label contains variable encoded information in a human readable form or a machine, where a rotating bellows applicator is used to transfer individual labels from a support strip. label on the tip of a single bellows and later on individual elements of products, where the means of detection detect a variable characteristic of the product elements, where each of the labels includes a translucent plastic substrate with front and rear surfaces, a light absorbing layer adjacent to the front surface of the substrate and a thermochromic layer adjacent to and in thermal contact with the light absorbing layer, where the output of the laser encoding means is used to apply the variable characteristics detected to the labels with their beam or output beams, characterized by: the application of the laser coding means output to the back surface of the substrate of the translucent label with the label on the tip of the bellows, cause the output of the laser coding means to form the detected variable characteristics, absorb the light energy of the output of the laser encoder means in portions from the light-absorbing layer and convert the absorbed light into heat, conduct The heat of the light absorbing layer in the thermochromic layer to cause portions of the thermochromic layer to change color to generate the variable encoded information in a human readable form or a machine. 52. The method of compliance with the claim 51, characterized in that the light absorbing layer is selected from the group consisting of carbon black, graphite and carbon nanotubes. 53. The method according to claim 51, characterized in that the light absorbing layer is included in the substrate. 54. The method according to claim 53, characterized in that the thermochromic layer is applied to the substrate by flexographic printing. 55. The method of compliance with the claim 51, characterized in that the laser coding means comprise a semiconductor arrangement in solid, addressable state. 56. The method according to claim 51, characterized in that the thermochromic layer has a front surface covered with a material that reflects the output of the laser coding means, characterized in that it also comprises the step of reflecting the output of the coding means. laser back to the light absorbing layer from the front surface of the thermochromic layer. 57. The method according to claim 51, characterized in that the thermochromic layer has reflecting particles included in it that reflects the output of the laser coding means back to the Absorbent layer of light. 58. The method according to claim 51, characterized in that the thermochromic layer further comprises particles for diffracting the light and providing the darkening of the light absorbing layer. 59. The method according to claim 51, characterized in that the thermochromic layer comprises a coating that includes a color former, color developer and sensitizer. 60. The method of compliance with the claim 51, characterized in that the plastic substrate is selected from the group consisting of polyethylene, polypropylene and polyester. 61. The method according to claim 51, characterized in that the bellows rotate between multiple indexing portions, characterized in that it also comprises the step of applying the output of the laser coding means to the label when the bellows rotate between two indexing positions. . 62. A multi-layered label for use in an apparatus for automatically applying labels to individual product elements, where each label has a visible front surface and a back surface and variable encoded information is applied to the label in human readable form or a machine, where a rotating bellows applicator for transferring individual labels from the label support strip and subsequently onto individual product elements, where the detection means detect a variable characteristic of the element of a product, where the output of a high intensity light source is used to apply the detected variable characteristics to each of the labels, characterized by: a plastic label substrate, the substrate having back and front surfaces, a light absorbing layer supported by or formed within the front surface of the substrate of the plastic label, the layer adapted to absorb light from the output of the high intensity source and to convert the absorbed light into heat, and a thermochromic layer in thermal contact with the light absorbing layer, the thermochromic layer forming the visible frontal surface of the label, where portions of the thermochromic layer change the appearance vis ual in response to the application of the output of the high intensity light source in the light absorbing layer, and the heat conduction converted from the light absorbed by the heat absorbing layer in the thermochromic layer. 63. The apparatus according to claim 62, characterized in that the light source of High intensity comprises an array of semiconductor diode in solid state addressable. 64. The apparatus according to claim 62, characterized in that the light absorbing layer is selected from the group consisting of carbon black, graphite and carbon nanotubes. 65. A multi-layer label for use in an apparatus for automatically applying labels to individual product elements, where each label has a visible front surface and a back surface and the variable encoded information is applied to the label in a human readable form or a machine, wherein the rotary bellows applicator is used to transfer individual labels of a label support strip onto the tip of a single bellows and subsequently onto individual items of products, wherein the detection means detect a variable feature of the element of a product, where the output of the high intensity light agent is used to apply the variable characteristic detected through the back surface of each of the labels, while each label is on the tip of a bellows, characterized by: substrate of plastic label, having a substrate surfaces later and frontal and being translucent at the outlet of the high intensity light source, and a thermochromic layer forming the front, visible surface of the label, where portions of the thermochromic layer change their visual appearance in response to the application of the light source outlet of high intensity through the substrate and towards the thermochromic layer. 66. The apparatus according to claim 65, characterized in that the high intensity light source is a single C02 laser.