Patent Grant
11819894
The present application is a United States national stage application of International patent application PCT/IB2018/054699 that was filed on Jun. 26, 2018 designating the United States, the contents of this document being herewith incorporated by reference in its entirety.
The invention is in the field of foil material embossing by means of cooperating rollers that comprise structured surfaces.
The present invention relates to a method and apparatus for the relief embossing of packaging films such as those used in the tobacco and food industry, for chocolate, butter or similar foods. The so-called inner liners originally consisted of integral aluminum foils, which were passed between two rolls for embossing (see, for example, WO2017/108516).
In parallel with the development of embossing technology and the improved quality and lifetime of the embossing rollers, a change from integral aluminum foils to paper films that were thinner and metal-film coated was implemented for environmental reasons.
At the same time, there was an increased demand around the year 2000 for attractive technical means to achieve intensified advertising on inner liners.
A known embossing-roller system, such as a pin-up/pin-up system 100 in
From the top view shown
Following the prior art taught in EP0925911 B2, the same inventor patented in EP1324877 B1 a device for producing embossing effects, which allows embossing on packaging films of signs with location and/or light-source-dependent optical and aesthetic effects in reflected light, as well as security features that are comparatively difficult to copy. These embossing effects enable the designer to add optionally shades that are highly dependent on the viewing angle. However, the original aim of the approach taught by EP1324877 B1 was to produce a variable embossing effect that exhibits the same intensity ratios in the reflected light for the viewer independent of the viewing location and without constant adjustment of a roller pressure when embossing. This goal could not be achieved with the approach described in EP1324877 B1.
If for example at least one side of foil material 302 is integral aluminum with specific material properties, then with an irradiation intensity of I°=1.0 of the impinging visible light 305, this aluminum foil surface exhibits a direct reflectance of approximately I′=0.9 per unit area. On the other hand, a metallized film obtained by vapor deposition of aluminum generally has a direct reflectance of only I″=0.8 per unit area. Practically, by skillful choice of truncation heights H of embossed truncated pyramidal shapes, four different discernible contrast levels may be achieved which is sufficient for security applications but is insufficient for aesthetic purposes.
The low level of light exploitation resulting from the use of the basic pin-up/pin-up embossing technique is an obstacle to the development of modern, brilliant embossing effects at high production speeds.
EP1324877 B1 represents a prior art that has been in use since about 2001, and which essentially changed only through the mastery of short pulse laser engraving. The further development of fine-embossing technology proved promising. The laser-based engraving technique has enabled for the first time pin-up/pin-down engraving of embossing rollers, e.g., in WO2015/028939 A1. WO2015/028939 A1 pointed the way to a high precision, easily reproducible production of complementary embossing rollers, which until at the time of filing of the international application was only possible with great effort. Reliefs were built using exaggerated elevation and pedestals in order to create optically pleasing brilliance in logos. However, this technique did not allow creating half-toning directly but only using some crude approximation.
In order to account for the expected further development of the aesthetic aspects of embossing as well as the tendency of a very-low degree of metallization, the object of the present invention is to create brilliant, high-quality, and operationally easy-to-control on-line-embossing results in foil material such as traditional packaging materials and films such as metallic foils, metallized papers, polymer films or laminates. The strong dependency on the embossing pressure and the viewing angle in EP1324877 B1 must be greatly improved, if possible eliminated altogether.
In a first aspect, the invention provides a method of embossing individually light-reflecting areas on a foil material, the method comprising feeding a foil material into a roller nip between a pair of rollers, wherein the pair of rollers comprises a first roller and a second roller, providing each of the first roller and second roller at their respective surfaces at least in a determined perimeter, respectively with a plurality of polyhedron-shaped positive projections and a plurality of negative projections complementary to the positive projections, wherein the determined perimeter comprises at least one positive projection, whereby the plurality of positive projections are arranged according to a 2-dimensional grid, and whereby each one of the plurality of positive projections extends over an individual height from a base side of the positive projection at the surface of the first roller to a top side of the positive projection in a direction away from a rotation axis of the first roller, and each negative projection extends from the surface of the second roller to a bottom side of the negative projection in a direction towards the rotation axis of the second roller. The plurality of polyhedron-shaped positive projections seamlessly and gaplessly join with those corresponding negative projections at the intended embossing of the foil material, hence enabling a homogeneously jointed embossed polyhedron-like shape in the foil. The method further comprises, for the purpose of
In a preferred embodiment, the step of adjusting comprises at least designing each one of the plurality of the positive projections of the 2-dimensional grid, by departing from a determined base shape which has a base surface delimited by a base perimeter intended to be positioned on the surface of the first roller and a 3-dimensional shape described by a 3-dimensional shape-contour function, by applying either one operation of the following list
In a further preferred embodiment, the step of adjusting comprises at least designing each one of the plurality of the positive projections of the 2-dimensional grid, by departing from a determined base shape which has a base surface delimited by a base perimeter intended to be positioned on the surface of the first roller and a 3-dimensional shape described by a 3-dimensional shape-contour function, by applying either one operation of the following list:
In a further preferred embodiment, the step of adjusting comprises at least designing each one of the plurality of the positive projections of the 2-dimensional grid, by departing from a determined base shape which has a base surface delimited by a base perimeter intended to be positioned on the surface of the first roller and a 3-dimensional shape described by a 3-dimensional shape-contour function, by applying either one operation of the following list:
In a further preferred embodiment, the 2-dimensional grid comprises a tessellation of grid surfaces, each grid surface comprising a grid surface perimeter with a plurality of corners, wherein single ones of the plurality of positive projections are positioned at corresponding corners, each corner comprising at most a single positive projection.
In a further preferred embodiment, the 2-dimensional grid comprises a tessellation of grid surfaces, each grid surface comprising a grid surface perimeter with a plurality of corners, wherein single ones of the plurality of positive projections are positioned in corresponding individual grid surfaces, each individual grid surface comprising at most a single positive projection.
In a further preferred embodiment, the 2-dimensional grid is an unstructured grid.
In a further preferred embodiment, the 2-dimensional grid is a regular grid.
In a further preferred embodiment, the 2-dimensional grid is one of the list comprising: a Cartesian grid, a rectilinear grid, a curvilinear grid.
In a further preferred embodiment, the 2-dimensional grid comprises a plurality of rows and columns, the tessellation of grid surfaces is organized in the plurality of rows and columns, and further single ones of the plurality of positive projections are positioned in corresponding individual grid surfaces in rows. The positive projections are spaced among each other according to a value of a first step function that describes a distance between grid surfaces in a direction of the row. Adjacent rows of positive projections are separated by a value of a second step function that describes a distance between grid surfaces in a direction of the column.
In a further preferred embodiment, wherein in each of the rows of positive projections, between two consecutive positive projections, a second negative projection is provided on the first roller, such that a plurality of second negative projections becomes arranged in the same row as the positive projections, the second negative projections of the row being regularly spaced among each other according to the value of the first step function, and whereby adjacent rows of second negative projections are separated by the value of the second step function. Each second negative projection extends from the surface of the first roller to a bottom side of the second negative projection in a direction towards the rotation axis of the first roller. The method further comprises, from one row to an adjacent row, providing next to a positive projection from the one row in the adjacent alignment a further second negative projection distant from the positive projection in column direction, whereby two consecutive second negative projections in a same column are separated by the value of the second function. The method further comprises providing on the second roller a plurality of second positive projections complementary to the second negative projections, and the plurality of second negative projections seamlessly and gaplessly join with those corresponding second positive projections at the intended embossing of the foil material.
In a further preferred embodiment, the method further comprises providing the first roller at least on the surface in the determined perimeter, with a relief topography comprising at least one of an elevation or a depression of the surface, providing on the second roller a complementary relief topography complementary to the relief topography, whereby the 2-dimensional grid is projected onto the relief topography.
In a further preferred embodiment, the step of providing each of the first roller and second roller at their respective surface with respectively positive and negative projections applies to surfaces of a plurality of determined perimeters, and the 2-dimensional grid is different for each of at least two surfaces of distinct determined perimeters, each of the 2-dimensional grids being associated to its own table of reflectivity values.
In a further preferred embodiment, the individual height (h) is less or equal to 500 μm.
In a further preferred embodiment, the foil material is anyone of the list comprising packaging material and films such as metallic foils, metallized papers, polymer films, laminates and the like.
In a further preferred embodiment, the foil material is for anyone application of the list comprising a seal pack with decoration for, e.g., smoking articles, a blister pack with decoration on a cover foil for, e.g., smoking articles or medication, a soft-wrap for sweet goods, a Tetra Brik (registered trademark) with decoration, a decoration of cover foil for beverage capsules, a wrapping-decoration of chewing gum.
In a further preferred embodiment, the method further comprises operating the pair of rollers in a quick-change device, the quick-change device including a housing with a first and a second mounting for receiving respectively a first roller carrier and a second roller carrier, the first roller carrier configured for fastening the first or the second roller which is driven via a drive and the second roller carrier configured for fastening respectively the second or the first roller, the quick-change device further configured to enable a pushing of the first roller carrier into the first mounting and the second roller carrier into the second mounting.
In a second aspect, the invention provides an embossing device configured for embossing of individually light-reflecting areas on a foil material, the device comprising a pair of roller configured to form a roller nip for admission of the foil material, wherein the pair of rollers comprises a first roller and a second roller,
In a preferred embodiment, each one of the plurality of the positive projections of the 2-dimensional grid, is described by departing from a determined base shape which has a base surface delimited by a base perimeter intended to be positioned on the surface of the first roller and a 3-dimensional shape described by a 3-dimensional shape-contour function, by applying either one operation of the following list
In a further preferred embodiment, each one of the plurality of the positive projections of the 2-dimensional grid, is described by departing from a determined base shape which has a base surface delimited by a base perimeter intended to be positioned on the surface of the first roller and a 3-dimensional shape described by a 3-dimensional shape-contour function, by applying either one operation of the following list:
In a further preferred embodiment, each one of the plurality of the positive projections of the 2-dimensional grid, is described by departing from a determined base shape which has a base surface delimited by a base perimeter intended to be positioned on the surface of the first roller and a 3-dimensional shape described by a 3-dimensional shape-contour function, by applying either one operation of the following list
In a further preferred embodiment, the 2-dimensional grid comprises a tessellation of grid surfaces, each grid surface comprising a grid surface perimeter with a plurality of corners, and wherein single ones of the plurality of positive projections are positioned at corresponding corners, each corner comprising at most a single positive projection.
In a further preferred embodiment, the 2-dimensional grid comprises a tessellation of grid surfaces, each grid surface comprising a grid surface perimeter with a plurality of corners, wherein single ones of the plurality of positive projections are positioned in corresponding individual grid surfaces, each individual grid surface comprising at most a single positive projection.
In a further preferred embodiment, the 2-dimensional grid is an unstructured grid.
In a further preferred embodiment, the 2-dimensional grid is a regular grid.
In a further preferred embodiment, the 2-dimensional grid is one of the list comprising: a Cartesian grid, a rectilinear grid, a curvilinear grid.
In a further preferred embodiment, the 2-dimensional grid comprises a plurality of rows and columns, the tessellation of grid surfaces is organized in the plurality of rows and columns, further wherein single ones of the plurality of positive projections are positioned in corresponding individual grid surfaces in rows,
In a further preferred embodiment, in each of the rows of positive projections, between two consecutive positive projections, a second negative projection is provided on the first roller, such that a plurality of second negative projections becomes arranged in the same row as the positive projections, the second negative projections of the row being regularly spaced among each other according to the value of the first step function, and whereby adjacent rows of second negative projections are separated by the value of the second step function. Each second negative projection extends from the surface of the first roller to a bottom side of the second negative projection in a direction towards the rotation axis of the first roller. The device further comprises, from one row to an adjacent row, providing next to a positive projection from the one row in the adjacent alignment a further second negative projection distant from the positive projection in column direction, whereby two consecutive second negative projections in a same column are separated by the value of the second function. The device further comprises on the second roller a plurality of second positive projections complementary to the second negative projections, and the plurality of second negative projections seamlessly and gaplessly join with those corresponding second positive projections at the intended embossing of the foil material.
In a further preferred embodiment, the device further comprises on the first roller at least on the surface in the determined perimeter, a relief topography comprising at least one of an elevation or a depression of the surface, on the second roller a complementary relief topography complementary to the relief topography. The 2-dimensional grid is projected onto the relief topography.
In a further preferred embodiment, on each of the first roller and second roller there is comprised at their respective surface respectively positive and negative projections in surfaces of a plurality of determined perimeters, and the 2-dimensional grid is different for each of at least two surfaces of distinct determined perimeters, each of the 2-dimensional grids being associated to its own table of reflectivity values.
In a further preferred embodiment, the individual height (h) is less or equal to 500 μm.
In a further preferred embodiment, the foil material is anyone of the list comprising packaging material and films such as metallic foils, metallized papers, polymer films, laminates and the like.
In a further preferred embodiment, the foil material is for anyone application of the list comprising a seal pack with decoration for, e.g., smoking articles, a blister pack with decoration on a cover foil for, e.g., smoking articles or medication, a soft-wrap for sweet goods, a Tetra Brik (registered trademark) with decoration, a decoration of cover foil for beverage capsules, a wrapping-decoration of chewing gum.
In a further preferred embodiment, the device further comprises a quick-change device configured to operate the pair of rollers, the quick-change device including a housing with a first and a second mounting for receiving respectively a first roller carrier and a second roller carrier, the first roller carrier configured for fastening the first or the second roller which is driven via a drive and the second roller carrier configured for fastening respectively the second or the first roller, the quick-change device further configured to enable a pushing of the first roller carrier into the first mounting and the second roller carrier into the second mounting.
The invention will be better understood through the detailed description of preferred embodiments of the invention, and in view of the figures, wherein
In a first step towards addressing the object of the invention, the invention departs from prior art reference WO2015/028939 A1 that enables to obtain an embossed product with a better reflectivity of the metallized surfaces, as well as for the embossing rollers, a precise generation of pyramid shapes in the micrometer range. By using exaggerated relief heights as well as the usage of pedestal effects, increased brilliance in logo designs is achieved. However, it is noted that there was no means to create shading or half-toning using the teachings of WO2015/028939 A1.
A recent successful development of a new basic embossing structure forms the basis for the significant increase in the brilliance resulting from embossed structures. The new basic embossing structure provides a solution for fine embossing that allows producing checkered-style and larger uniformly embossed areas in a step length of about 50 to 250 μm. The new basic embossing structure further provides a configuration that also reduces uncontrollable contraction in the axial direction while foils are being embossed. In addition, the new basic embossing structure provides a solution that allows producing the fine embossing over areas in a homogeneous manner on the foil.
The new basic embossing structure may be understood from the following description of an embossing method that allows embossing a material from both sides. The embossing method comprises at least feeding the foil material into a roll nip between a pair of a first roll and a second roll, providing the first roll and the second roll each with a plurality of positive projections and a plurality of negative projections of identically shaped polyhedral structures, the positive projections are elevated above a mean cylindrical surface of their roll, and the negative projections are recesses reaching below the mean cylindrical surface of their roll, a first subset of the plurality of positive projections being disposed with a first periodicity on a first grid in axial direction and a second periodicity on the first grid in circumferential direction on the first roll, and a second subset of the plurality of negative projections being disposed with the first periodicity in axial direction and the second periodicity in circumferential direction on the first grid intertwined with the positive projections, in axial and circumferential directions respectively, and a third subset of the plurality of positive projections and a fourth subset of the plurality of negative projections being disposed on a second grid complementary to the first grid, on the second roll, each of the positive projections and the negative projections on the first roll during operation of the rolls and in the roll nip, except for projections located on edges of the first grid, being surrounded on all sides by positive projections and negative projections on the second roll, the positive projections of the first roll together with alternating corresponding negative projections on the second roll forming during the operation of the rolls and in the roll nip, a first straight line (y-y) substantially parallel to the axial direction, and the negative projections of the first roll together with alternating corresponding positive projections on the second roll forming during the operation of the rolls and in the roll nip, a second straight line (x-x) substantially parallel to the axial direction. The embossing method further comprises disposing in the first grid the positive projections and the negative projections such that in the axial direction on the first roll each positive projection shares a lateral base border with at least one negative projection adjacent to the positive projection, where the first straight line (y-y) and the second straight line (x-x) are coincident in a single third line (z-z), and during the operation of the rolls and in the roll nip, all lateral oblique surfaces of the positive and negative projections of the first roll are just above the surface in full faced view with the corresponding lateral oblique surfaces of the respective negative and positive projections of the second roll, thereby enabling a homogeneous distribution of pressure to the material.
In
The use of the embossing pattern of
Returning to
Using the embossing pattern with the new basic embossing structure, it is possible to obtain a homogeneous distribution of pressure to the material, i.e., a regular and homogenous balance between the pressure on the lateral oblique surfaces of the positive projections P and negative projections N, mitigated perhaps only by variations of the material thickness that occur over a certain range of tolerances. Furthermore, axial contraction of the embossed foil is reduced and a smoother surface is obtained compared to the older embossing technologies of the Applicant.
The embossing using the new basic embossing structure may also be called the polyhedron embossing technique.
A comparison of the spatial density of the embossed metallized areas between those achieved by using the approaches in EP0925911 and those achieved using the polyhedron embossing technique provides detailed information on the significant increase in the brilliance resulting from embossed structures.
It can be ascertained easily that the polyhedron embossing technique provides a doubling of the embossed, metallically reflecting surface in practice compared to prior art, such as, e.g., EP1324877 B1, since embossed structures obtained with positive projections and negative projections can be controlled. While with prior-art embossing systems like the ones shown for example in
Hence, in a further step towards addressing the object of the invention, which starts from the new basic surface embossing structures with pyramids or any other polyhedron shape of different heights, one comes closer to the goal of the invention. As described herein above for the new basic embossing structure, a polyhedron-like denture is used here. This means that opposing individual embossing teeth, i.e., a positive projection on one roller and a corresponding negative projection of the counter roller, of the roller pair are exactly complementary.
The individual embossing teeth in any surface of at least a determined perimeter of a roller. Taking for example a plurality of positive projections as an embodiment of the embossing teeth, theses may be arranged according to a 2-dimensional grid comprising a tessellation of grid surfaces.
The individual embossing teeth may have respectively an individual polyhedric shape with one or more flat top surfaces, possibly of the same type for at least a part of the first roller surface, e.g., for at least a surface having a determined perimeter and which is covered by the individual embossing teeth. The individual polyhedric shape is intended to emboss individual light-reflecting areas in the foil material in order that the reflectivity of such light-reflecting area is adjusted to correspond to a predetermined reflectivity value. In an example embodiment, the individual embossing teeth are arranged on the first roller according to a 2-dimensional grid, and the individual polyhedric shape of each tooth must be formed in line with a table of reflectivity values for the 2-dimensional grid that describes which value of reflectivity of the embossed foil material the embossing of each tooth must produce. Such a 2-dimensional grid may for example comprise 5 rows of 5 individual embossing teeth, that is 25 embossing teeth, and the table of reflectivity values may for example be given as percentages as follows:
In the above table, it is, for example, indicated that for row 1, column 1, the shape of the embossing tooth should be made to emboss individual light-reflecting areas that in total have a reflectivity of 20%. Another example for row 4, column 5 indicates that the shape of the embossing tooth should be made to emboss individual light-reflecting areas that have a total reflectivity of 40%. The reflectivity may be achieved by adjusting for each of the plurality of light-reflecting areas to provide, an orientation and shape of the corresponding positive projection (embossing tooth) in the 2-dimensional grid that is intended to emboss the light-reflecting areas. This adjustment may involve choosing a specific polyhedric shape, adjusting its height, its size, its tilting angle, and then modulating the achieved reflectivity by applying operations such as for example an offset operation, a gain factor operation or a cut-off operation. A few examples of this non-limitative list of operations will be described herein below in connection with
This example with arbitrary numbers will be better understood after the explanations below in relation for
Referring now to
The table in
More specifically, referring to cell a), this shows an operation of shaping an upper part of the determined base shape 1000 to obtain the designed positive projection 1002, the resulting shape of the upper part, i.e., the designed positive projection 1002 having a modified height H reduced by an individual offset Ioff as compared to the individual height h, whereby
H=h−Ioff.
The designed positive projection 1002 is intended to be positioned at the surface of the first roller, which is represented as a reference at the surface 1001 in cell a).
In cell b), in addition to applying a second individual vertical offset Ioff2 (Ioff2 not represented in cell b)), in a direction perpendicular to the surface 1001 (which is the same as in cell a)) to modify an overall height of the determined base shape 1000 to become H1, a further transformation leading to a lateral offset or shift of all points of the determined base shape in a direction parallel to the surface 1001 is applied to obtain a designed positive projection 1010. It is noted that in the example of cell b), for sake of a better understanding, the base points 1011 and 1012, which are virtual points, and indicated at the end of virtual prolongations 1013 of sides of the designed positive projection 1010 are also subjected to the vertical and lateral shift.
In cell c), a determined base shape 1021 represented again in sectional view has a similar shape as the determined base shape 1000, but a designed positive projection 1020 has a more complex top side structure comprising two summits 1022 and 1023 and more than 2 sides, at various angles of inclinations, in contrast to the determined positive projection 1002 from cell a) which corresponds to a sectional view of a regular pyramid. However, similarly to the operation applied in cell a), here in cell c), an upper part of the determined base shape 1021 is shaped to obtain a designed positive projection 1020 that has for one summit 1023 a modified height H2 according to a third individual offset Ioff3, but for other points of a shape contour of the designed positive projection, other individual offsets are applied, for example to obtain the modified height H3 of summit 1022. In overall this is represented by variable lengths of the one-pointed arrows in cell c). The shape contour of the positive projection is shown in 2 dimensions as cell c) represents a cross section, but if the whole surface of the designed positive projection 1020 is taken under consideration, this may be obtained by applying to a 3-dimensional shape of the determined base shape 1021, described by a 3-dimensional shape-contour function, a 3-dimensional offset, which results in the different heights of the designed positive projection. The designed positive projection 1020 is intended to be positioned at the surface of the first roller.
In cell d), an operation of applying an individual gain or multiplication factor to the determined base shape 1000 is executed to obtain a designed positive projection 1030, the operation being configured such to maintain a base surface and base perimeter of the determined base shape—represented by the section delimited by points 1031 and 1032 in the sectional view of cell d)—intended to be positioned at the surface of the first roller—represented here by the surface 1001. This results in an overall deformation of the determined base shape 1000 in height direction in proportion to an individual gain factor Igain. For the height H of the designed positive projection, we have the relation:
H=Igain×h.
In cell e), in addition to an operation of applying a gain factor to obtain the overall height of the designed positive projection, a lateral deformation is also operated on all points of the determined base shape to obtain the designed positive projection 1040, except on the points 1031 and 1032 that delimit the base surface at the surface of the roller of the determined base shape of the designed positive projection 1040.
In general, it may be noted that the determined base shape has a 3-dimensional shape described by a 3-dimensional shape-contour function, which is not further analytically detailed here. The operation of applying an individual gain factor may be described as follows: an individual 3-dimensional gain-factor function is applied to the determined base shape to obtain the designed positive projection, that is used to emboss the light-reflective area intended to have a desired reflectivity, the individual 3-dimensional gain-factor function being configured to be applied to the 3-dimensional shape-contour function thereby such that the designed positive projection has the same base perimeter as the determined base shape, the designed positive projection has no part that overlaps beyond the base perimeter, and any point in the contour of the designed positive projection is free from overlap with another point of the contour maintaining a base surface of the determined base shape intended to be positioned at the surface of the first roller and, resulting in an overall deformation of the determined base shape in proportion to the individual 3-dimensional gain factor.
In cell f), a determined base shape 1051 is represented again in sectional view using dotted lines, and the designed positive projection 1050 has a more complex top side structure with at least two summits 1052 and 1053 and a plurality of sides at various angles of inclinations. This more complex top structure, which is just a part of an overall 3-dimensional top side of the desired positive projection, results from an individual 3-dimensional gain-factor function being applied to the 3-dimensional shape-contour function of the determined base shape 1051. The desired positive projection 1050 is intended to be positioned at the surface of the first roller.
In cell g), the determined base shape 1000 is represented partly in dashed lines for its top side, and partly in a texture shape that corresponds to a designed positive projection 1060. The non-textured part of the determined base shape corresponds to the result of an operation comprising cutting-off the top of the determined base shape 1000 according to an individual shape 1061 along an individual intersection 1062 with the determined base shape 1000. The individual shape 1061 is represented above the designed positive projection 1060 for a better understanding. In a further preferred embodiment the individual shape not only affects the shape of designed positive projection 1060, but may extend to further positive projections intended to be positioned on either sides of the designed positive projection on the surface of the roller represented here by surface 1001, and hence affect the shapes of the further projections accordingly. It is understood that the individual shape is of virtual nature, and that the cutting-off of the determined base shape is operated according to a virtual representation of the individual shape, as may easily be done by a person skilled in the art for the shaping as such only. In the example of cell g), the designed positive projection 1060 corresponds to a pyramid that is cut-off parallel to the surface 1001. The designed positive projection 1060 is intended to be positioned at the surface of the first roller.
In cell h), a similar operation of cutting off as in cell c) is executed, whereby the individual intersection results in a slanted top side 1071 of a designed positive projection 1070.
In cell i), a similar operation of cutting off as in cells g) and h) is executed, whereby the individual intersection results in a more complex top side 1081 of a designed positive projection 1080.
The adjusting of a determined base shape to a desired positive projection may be modeled more generally with the help of transformation matrices. For further details, see also [David Salomon: “The Computer Graphics Manual”, Springer, 2011 Edition, ISBN-13: 978-0857298850].
An offset in 3-dimensional space as applied to the determined base shape in order to move this base shape to the origin of the coordinate system X(fx, fy, fz) according to the translation transformation T as follows:
X(fx,fy,fz)=T(fx,fy,fz)
which, when expressed with the transformation matrix is:
Subsequently, a shear function in the xy plane and a scaling function in z-axis followed by the inverse offset operation to the original starting point and with the transformation matrix as previously demonstrated allow to obtain all desired positive projections from determined base shapes, according to the parameters of the matrices, and is expressed by the formula as follows:
X(fx,fy,fz,a,b,sx,sy)=T(fx,fy,fz)·SH(a,b)·S(sz)·T(−fx,−fy,−fz)
and using matrices:
Referring now to
In a preferred example embodiment, on both rolls, a step spacing individual embossing teeth may remain the same along a given first direction, i.e., it also may remain the same along another given second direction but possibly with another value than that used to the first direction. Hence, in case the first direction and the second direction are axial and radial directions respectively, a value of axial steps may differ from a value of radial steps.
Resulting embossed foil materials comprise embossed tooth-shapes all over the surface. At the time of filing of the present patent application, the usual step lengths s (see
The principle described in EP1324877 B1 allowed the tobacco industry in year 2000 (prior art) to manufacture from 200 to about 500 sections/min for cigarette packaging in online operation, while over 1000 sections/min are possible at the time of filing the present patent application.
For example,
The pyramids, which effectively are positive projections from the roller surface, are arranged in a plurality of rows and columns, more specifically in the present example, in a plurality of alignments on axially oriented lines, for example a first axial line 1206 and a second axial line 1207 shown in dashed lines. The pyramids are spaced in the rows according to a value of a first step function, which in the present example describes a regular spacing among each other according to an axial step AS1. Adjacent axially oriented alignments of pyramids, such as the first axial line 1206 and the second axial line 1207 are separated in distance according to a value of a second step function, which in the present example is a radial step RS1.
The axial step AS1 and the radial step RS1 may be equal, but in preferred embodiments, depending on the overall requirements, they may also differ from each other according to the first step function and the second step function respectively. These functions may be of any type, for example linear (as in the present example), non-linear, etc.
The variations of the truncations of the pyramids, when considered overall the pyramids, define the individual shape that is cut-off in the pyramids according to a corresponding individual intersection, over the corresponding surface of the roller that comprises the pyramids. In the example of
For example,
In other words, the height variations of the hexagonal pyramids may be obtained by executing the operation of applying an individual gain factor as explained in relation to cell d) in the table of
The hexagonal pyramids, which effectively are positive projections from the roller surface, are arranged in a plurality of alignments on axially oriented lines, for example a third axial line 1304 and a fourth axial line 1305 shown in dashed lines, the pyramids being regularly spaced among each other according to an axial step AS2. Adjacent axially oriented alignments of hexagonal pyramids, such as the third axial line 1304 and the fourth axial line 1305 are separated in distance by a radial step RS2.
In
The principle illustrated in
Referring now to
More specifically,
Referring now to
Continuing the explanation of
Drawn circles in
The applications as shown in
The invention may find use in decorative embossing of luxury objects, e.g., watches or jewelry, but also in the area of pharmaceuticals, food industry, sweets, snacks, etc.
Since the height of the embossing structures may be kept to a minimum while still getting very strong and weakly viewing-angle dependent shading or dithering effects, the novel embossing method may be applied to implementations where the surface of the embossed material has to be kept nearly flat.
While the invention was described to be used with rollers, and more particularly a pair of rollers, the discussed structures may well be applied to planar embossing tools for planar embossing between a pair of planar embossing tools. This is particularly of interest in case the material to emboss becomes too rigid, and rotary embossing no more provides sufficient force to deform the material during the short time-window of the material passing between the rolls. The person skilled in the art may conclude that the technology of the invention (method and device) may be adapted to the use of embossing material that is more rigid. This could be on conveyor belts that bring the material to the embossing tool, an embossing hammer that is applied during an appropriate interval to the material.
In addition, the rotational manner of embossing according to the invention may also be used when the material is presented by other means to the embossing rollers, e.g., when the material to emboss is planar, un-deformed and stamp embossed.
In the present example, the second die roller is driven by the driven first die roller 2606 in each case via toothed wheels 2609 and 2610, which are located at an end of the rollers. In order to ensure the demanded high precision of synchronization, the toothed wheels are produced very finely. Other synchronization means are also possible, e.g., electric motors.
When pushed into the mountings, a roller axle (not shown in the
In the present description, it is referred often to the first roller and the second roller when describing the pair of rollers that are used to produce the embossed foil material. In the actual embossing system, either one of the first roller and the second roller may be the roller that is driven, this having no impact on the invention.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IB2018/054699 | 6/26/2018 | WO |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2020/002970 | 1/2/2020 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 3673839 | Nielsen et al. | Jul 1972 | A |
| 5007271 | Boegli | Apr 1991 | A |
| 5598774 | Boegli | Feb 1997 | A |
| 6080276 | Burgess | Jun 2000 | A |
| 6176819 | Boegli et al. | Jan 2001 | B1 |
| 6302998 | Burgess | Oct 2001 | B1 |
| 6665998 | Boegli | Feb 2003 | B1 |
| 6715411 | Boegli | Apr 2004 | B1 |
| 7036347 | Boegli | May 2006 | B2 |
| 7147453 | Boegli | Dec 2006 | B2 |
| 7229681 | Boegli | Jun 2007 | B2 |
| 7971526 | Blenke | Jul 2011 | B2 |
| 8038922 | Boegli | Oct 2011 | B2 |
| 8430663 | Boegli | Apr 2013 | B2 |
| 8495900 | Boegli | Jul 2013 | B2 |
| 8932044 | Boegli | Jan 2015 | B2 |
| 9140834 | Boegli | Sep 2015 | B2 |
| 9156107 | Boegli et al. | Oct 2015 | B2 |
| 9180643 | Boegli | Nov 2015 | B2 |
| 9481141 | Boegli | Nov 2016 | B2 |
| 9505167 | Boegli | Nov 2016 | B2 |
| 9579924 | Boegli | Feb 2017 | B2 |
| 9636885 | Boegli et al. | May 2017 | B2 |
| 9809927 | Boegli | Nov 2017 | B2 |
| 9939725 | Bocgli et al. | Apr 2018 | B2 |
| 9993895 | Boegli et al. | Jun 2018 | B2 |
| 10083253 | Boegli et al. | Sep 2018 | B2 |
| 10183318 | Boegli et al. | Jan 2019 | B2 |
| 20050279147 | Boegli | Dec 2005 | A1 |
| 20080292885 | Dohring | Nov 2008 | A1 |
| 20100061619 | Boegli | Mar 2010 | A1 |
| 20120018993 | Boegli et al. | Jan 2012 | A1 |
| 20120292821 | Boegli | Nov 2012 | A1 |
| 20140059977 | Boegli | Mar 2014 | A1 |
| 20150059599 | Boegli | Mar 2015 | A1 |
| 20160075077 | Boegli et al. | Mar 2016 | A1 |
| 20160193868 | Espe | Jul 2016 | A1 |
| 20160200066 | Boegli | Jul 2016 | A1 |
| 20170066079 | Reisse et al. | Mar 2017 | A1 |
| 20170282635 | Boegli et al. | Oct 2017 | A1 |
| 20180220698 | Boegli et al. | Aug 2018 | A1 |
| 20180370175 | Boegli et al. | Dec 2018 | A1 |
| 20200324505 | Boegli et al. | Oct 2020 | A1 |
| Number | Date | Country |
|---|---|---|
| 772613 | Sep 2000 | AU |
| 2367423 | Mar 2000 | CA |
| 2382597 | Nov 2001 | CA |
| 202017105458 | Jul 2017 | DE |
| 1324877 | Jun 2006 | EP |
| 0925911 | Nov 2006 | EP |
| 2572820 | Mar 2013 | EP |
| 2653301 | Oct 2013 | EP |
| 3300612 | Apr 2018 | EP |
| 3415306 | Dec 2018 | EP |
| WO 2007012215 | Feb 2007 | WO |
| WO 2015028939 | Mar 2015 | WO |
| 2017108516 | Jun 2017 | WO |
| WO 2018229557 | Dec 2018 | WO |
| Entry |
|---|
| Office Action issued in Indian Patent Application No. 202017054847 dated Jul. 12, 2022. |
| International Search Report dated Mar. 7, 2019 for Application No. PCT/IB2018/054699. |
| Written Opinion of the ISA dated Mar. 7, 2019 for Application No. PCT/IB2018/054699. |
| David Salomon, “The Computer Graphics Manual”, Springer, 2011 Edition, ISBN-13: 978-0857298850, 1 page of concise description. |
| Number | Date | Country | |
|---|---|---|---|
| 20210260633 A1 | Aug 2021 | US |
