Device for embossing packaging material with a set of embossing rollers of the male-female die type
09636885 ยท 2017-05-02
Assignee
Inventors
Cpc classification
B31F2201/0741
PERFORMING OPERATIONS; TRANSPORTING
B31F2201/0738
PERFORMING OPERATIONS; TRANSPORTING
B31F1/07
PERFORMING OPERATIONS; TRANSPORTING
B31F2201/0774
PERFORMING OPERATIONS; TRANSPORTING
International classification
Abstract
The embossing device for embossing packaging material comprises a set of embossing rollers with male die and female die rollers co-operating with one another, the surface of which is provided with texture elements, wherein the texture elements (M6R6) on the surface of the female die roller (M6), which are assigned to the texture elements (P6E6) on the surface of the male die roller (P6) are not inversely congruent by an amount of above 15 m in axial and radial direction and the texture elements of the male die and female roller associated with one another comprise facets (F) for the purpose of local pressure elevation. A facet (F) comprises faces (FN), which with respect to the imaginary, continuous surface of the texture is inclined. With such facetted rollers, a very large variety of films can be embossed in an aesthetically appealing manner, wherein the films can be mainly employed in the tobacco and foodstuff industry.
Claims
1. An embossing device for embossing packaging material comprising: a set of embossing rollers including a male die roller and a female die roller co-operating with each other, a surface of the male die roller having texture elements, and a surface of the female die roller having texture elements, wherein the texture elements of the female die roller and the texture elements of the male die roller that are associated to the texture elements of the female die roller, include intended deviations so that a texture element of the female die roller and an associated texture element of the male die roller are not inversely congruent, the intended deviations include, an angular deviation between a side of the texture element of the female die roller and an associated side of the texture element of the male die roller being up to 20, and a linear deviation between the texture element of the female die roller and an associated texture element of the male die roller being above 15 m in an axial and a radial direction, and wherein the texture elements of the male die roller, which are assigned to the texture elements of the female die roller, have facets configured to increase a local pressure.
2. The embossing device according to claim 1, wherein each of the facets have faces which are inclined at a defined angle, with respect to an imaginary and continuous surface of a texture of a logo represented by the texture elements.
3. The embossing device according to claim 1, wherein a minimal area for each of the facets is 0.4 mm0.4 mm, or 0.16 mm.sup.2.
4. The embossing device according to claim 1, further comprising: a second female die roller, wherein the male die roller, the female die roller, and the second female die roller are arranged such that the male die roller with a male die elevation first interacts with the female die roller with an associated first female die depression, and thereafter the male die roller with the male die elevation interacts with the second female die roller and an associated second female die depression.
5. The embossing device according to claim 1, further comprising: a second male die roller, wherein the male die roller, the second male die roller, and the female die roller are arranged such that the female die roller with a female die depression first interacts with the male die roller with an associated male die elevation, and thereafter the female die roller with the female die depression interacts with the second male die roller with an associated second male die elevation.
6. The embossing device according to claim 4, wherein the male die roller, the female die roller, and the second female die roller are arranged in a three-roller embossing device, wherein the male die elevation is arranged on the male die roller in such a manner that during an embossing process, the male die elevation interacts first with recesses of the female die roller, and thereafter with recesses of the second female die roller.
7. The embossing device according to claim 4, wherein the male die roller, the female die roller, and the second female die roller are each arranged in pairs in a two-roller embossing device.
8. The embossing device according to claim 5, wherein the male die roller, the second male die roller, and the female die roller are arranged in a three-roller embossing device, wherein the female die depression is arranged on the female die roller in such a manner that during an embossing process, the female die depression interacts first with elevations of the male die roller, and thereafter with elevations of the second male die roller.
9. The embossing device according to claim 5, wherein the male die roller, the second male die roller, and the female die roller are each arranged in pairs in a two-roller embossing device.
10. The embossing device according to claim 1, wherein at least one of a height and a depth of the elevations and recesses and a number of embossing rollers are configured to create high or raised reliefs on the packaging material through multiple embossing, the at least one of the height and the depth and width being greater than remaining textures of the packaging material.
11. The embossing device according to claim 1, wherein a diameter of one of the embossing rollers is wider than the width of a web of the packaging material, the diameter being smaller by an amount S than the other embossing roller, wherein S has a value of over 0.02 mm.
12. The embossing device according to claim 1, wherein the surface of the embossing rollers is made of at least one of metal, hard metal, hard material, and ceramic, and wherein the surface is covered by a protection layer.
13. The embossing device according to claim 1, wherein the set of embossing rollers is arranged in a quick-change device such that the male die roller and the female die roller can be replaced individually and independently of each other, wherein the male die roller and the female die roller are rotatably held in a male die roller carrier and a female die roller carrier, respectively, and are fastened individually and removably independently from each other in a quick-change housing in a defined position, wherein an end of the male die roller carrier is held in a needle bearing and an other end of the male die roller carrier is held in a ball bearing.
14. The embossing device according to claim 13, wherein at least one of the male die roller carrier and the female die roller carrier includes a key at a lower part, and a corresponding slot at a bottom of the quick-change housing.
15. The embossing device according to claim 1, wherein the linear deviation between the texture element of the female die roller and the associated texture element of the male die roller is approximately 40 m in an axial and a radial direction.
16. The embossing device according to claim 1, wherein the linear deviation between the texture element of the female die roller and the associated texture element of the male die roller is approximately 120 m in an axial and a radial direction.
Description
(1) Further objects and advantages are obtained from the dependent claims and the following description. In the following, the invention is explained in more detail with the help of drawings of exemplary embodiments.
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(25) While the elevation P1E1 and the associated depression M1R1 are semi-spherical in shape, the elevation P1E2 and the associated depression M1R1 are textured, and in this case have so-called facets F. According to Brockhaus, facets are polished surfaces and in this sense, facets in this case are defined as flat part surfaces provided on a surface. Here, the part surfaces of a surface do not have the same dimensions among them.
(26) With respect to the mode of action and the advantages of the facets, the following physical considerations can be employed. The resolution capacity of the naked eye under ideal conditions is approximately 0.5 to 1, corresponding to 1 mm at 3-6 m or 0.1 mm at an eye distance of 30 cm to 60 cm. Similar to optical instruments, the resolution capacity is determined by the size of the pupil. The distance of the photo receptors in the fovea centralis, the location of keenest vision, is adapted to the resolution capacity of the eye, this distance amounts to approximately 0.3. In the case of average conditions, two points are separately perceptible when their angular distance is 2. In the case of faint objects and towards the edge of the field of vision, the visual acuity however diminishes noticeably. In contrast with this, the distinguishability of fine textures is greater. In the case of lines it can reach for example 0.3 in good contrast, which is achieved through inborn image processing in the brain.
(27) Based on the inner liner, a reflectiveness of 20-30% must be assumed in situ, which means that in the case of a piece of film which is irradiated with white light over a large area, a maximum of 20-30% of the irradiated light intensity is reflected. Because of the only lightly metallized surface the human eye therefore requires a minimal area of approximately 0.4 mm0.4 mm, or 0.16 mm.sup.2, in order to be able to clearly distinguish small areas contrast-wise. The image processing of the brain is thus responsible for two other effects: A) As is known from painting, complex forms can be recognised by humans when the contours and/or areas of an object are only suggestively visible. B) For as long as the angles of curvature of an object are constant or almost constant, even larger pieces of area are recognised with the help of a few bright dots respectively constructed in the brain. Prerequisite for this is that the intensity of the reflected light supplies sufficient contrast.
(28) As already indicated, the contrast, or the clear recognisability of free surfaces can be improved with in part elevated flat surfaces of any form, in this case called facets or polygons, which are raised on the male die roller or recessed on the female die roller. The facets mark the individual surface parts and are designed through size and arrangement that thanks to the higher specific embossing print great brilliance and thus a good aesthetic impression of the total embossing is created. This impression is created through the image processing of the human eye with the help of refraction edges, which cause a locally elevated embossing print.
(29) As is evident from
(30) With the help of
(31) If according to the known prior art only the inner L, i.e. according to the inner sides which perpendicularly stand on one another everywhere, were to be attached to the rollers, the film with this embossing depth would in all probability tear or with greatly reduced pressure be blurred or irregularly perceptible.
(32) In order to both protect the film as well as increase the contrast, all sides of the character are provided with oblique faces, wherein only the oblique faces L1S, B1S, S1S and L2S are numbered here. The oblique face S1S describes a gusset arranged between a long surface and a wide surface. The angle between the perpendicular sides and the oblique faces is substantially determined dependent on the size of the object and the condition of the film. This angle need not be the same everywhere.
(33) In the present case so far described, the facets created on the film consist of the oblique faces. In the case however that the facet angle does not satisfy the criteria described further down below, or the contrast is not satisfactory, facets FR are provided on the surface LO, see
(34) Starting out from the described example, many variations are conceivable. For example the angles , and , or the height HF can vary in each case provided the criteria stated further down below are satisfied.
(35) It is theoretically possible to attach the facets in any way, regardless of the size and shape of the same. Tests have shown however that certain criteria achieve optimal reflectiveness and thus mode of viewing an object when the following aspects are observed. Here, the angles in inclination, whether of the surface or of the lateral faces of the facet, are always based on the imaginary, continuous surface of the logo. Logo is to mean all figures or signs. 1. In order to perceive changes of the relief with a varying inclination a of under 55 the facet surfaces, which have an inclination of =7090, have to be separated by at least 0.04 mm height, see
(36) The above information shows that a facet is to mean a part surface that is flat as a rule, which comprises facet faces, which with respect to the imaginary and continuous surface of the logo are inclined at a defined angle.
(37) The stated values and conditions are exemplary details, with which good results can be achieved. However it is also conceivable that other values could realise good or satisfactory results.
(38) Since these textures are not teeth, the driving force of the male die roller driven via the belt drive 2 is transmitted to the female die roller via toothed wheels 3 and 4.
(39) In the
(40) In order to be able to state the intended deviations, the systematic errors, i.e. the tolerances during the production, have to be initially defined. As already mentioned, the improvements in the roller production aim among other things at producing more accurate and suitable textures for the fine embossing, thus resulting in the problem of producing close tolerances during the production. These tolerances are among other things also influenced by the quality of the surface of the rollers and it is therefore advantageous to use a hard surface.
(41) These can be solid hard metal rollers or metal rollers with a surface of hard metal, hardened steel or hard material such as ta-C, tungsten carbide (WC), boron carbide (B.sub.4C) or silicon carbide (SiC), solid ceramic rollers or metal rollers with a ceramic surface. All these are materials which are particularly suited for precision working, for example also with a laser system. In most cases it is advantageous to provide the surface of the embossing rollers with a suitable protective layer. Both embossing rollers have roller bodies which are stiffened against deformation with a hard surface region so that the surface geometry is retained even under high loads.
(42) For example, for an embossing roller with a length of 150 mm and a diameter of 70 mm and with the intended precision working in direction of rotation, an error of 2-4 m and in axial direction such of +/2 m is aimed at and in height, with a tooth height of 0.1 mm, such of 0.5 to 3 m. With an angle of two opposite tooth flanks of for example 80, an angular error of under 3 is aimed at. This produces for new rollers a maximum linear error of +/5 m, so that the fabrication-related deviations can amount up to approximately 10 m.
(43) However, since these values can be greatly influenced by the measurements and the production, an intended difference can be talked of only from a linear deviation of the male die textures from the female texture of 15 m and more in axial and radial direction and from an angular deviation of up to 20 for the total angle. The upper limit of the difference of the textures is set by the condition of the two rollers can co-operate without impairment.
(44) The intended difference of the respective associated textures on the male die and on the female die greatly depends on the material to be embossed. Accordingly, the linear difference of the distance for the embossing of a film that is approximately 30 m thick amounts to approximately 40 m and during the embossing of an approximately 300 m thick semi-cardboard, around 120 m.
(45) In the
(46) In the cases according to the
(47) Instead of a lowering, other spacing means can also be provided, such as for example an electronic or mechanical spacing control.
(48) In
(49) The female die roller M3 in
(50) The female die roller M4 from
(51) The same observations also apply to rounded textures and to the facet textures.
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(53) In the
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(57) It has also been shown that through the widening and increasing in height or deepening of the word dream this word is greatly emphasised, more greatly than with larger thickness, however with the same height, or depth of the lily. The widening and simultaneously heightening and deepening of a sign compared with a sign with smaller width and height, or depth brings about amplified emphasis of this sign.
(58) In
(59) In
(60) However, it is conceivable that the male die in each case co-operates in a two-roller system firstly with the one and then with the other female die roller, wherein in each case the male die roller P9 first interacts with the female die roller M9A and then the same male die roller P9 with the other female die roller M9B.
(61) This allows embossing of raised or deep figures without excessively straining the film. Here, tearing of the film in the locations of the deeper female die recesses can be avoided above all.
(62) A further example of an embossing device with three embossing rollers is shown in the
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(66) From the two sectional figures it is evident that the film being passed through between the embossing rollers is initially pre-embossed and subsequently embossed more deeply.
(67) Such a multiple roller device with a female (male) die roller and multiple male (female) die rollers as mating rollers, the elevations (recesses) of which associated with one another are greater in each case from mating roller to mating roller, is used for embossing so-called elevated textures. These are arranged on top of one another and can be embossed without tearing the film, which in the case of single embossing with the same textures would lead to the tearing of the film.
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(70) The use of multiple rollers with elevations and recesses of different depths allows the embossing of greatly elevated reliefs without over-straining the film in such a manner that it is perforated.
(71) Starting out from the above examples it is evident that the provision of logos of whatever shape with facets is not limited to a certain size of area, but a minimal area of 0.4 mm0.4 mm, corresponding to 0.16 mm.sup.2 and can be employed wherever a contrast improvement is desired.
(72) The previously known male die-female die rollers were always produced in pairs and because of the fact that the female die rollers are designed inversely congruent to the male die rollers, every time one of the rollers had to be replaced, the other roller of necessity also had to be replaced. Through the individual production of the embossing rollers according to the present invention it is now possible to individually replace both the male die roller as well as the female die roller, which brings with it a major advantage not only with respect to the different wear conditions but also with respect to the configuration possibilities.
(73) Quick-change devices for the usual pin-uppin-up rollers are known from U.S. Pat. No. 6,665,998 of the same applicant and have been in use throughout the world for the plurality of all cigarette paper embossing devices since. The axle of the mating roller there is moveable in the three coordinate directions in order to make possible self-synchronisation of the embossing rollers. This is no longer required with the rollers of the present invention which do not have any teeth any longer.
(74) The quick-change device 30 of the
(75) In the present example, the female die roller is driven by the driven male die roller 36 in each case via toothed wheels 3 and 4, which are located at an end of the rollers. In order to ensure the demanded high precision of synchronisation, the toothed wheels are produced very finely. Other synchronisation means are also possible, e.g. electric motors.
(76) From the section of
(77) The roller axle 50 of the female die roller 37 is mounted on one side, in the drawing on the left, in a wall 51 of the roller carrier 35 and on the other side in a second wall 52 of the roller carrier. The edges 53 of lid 54 of the roller carrier are embodied as keys which can be pushed into the corresponding T-slot 55 in the housing 31. Here, the one side wall 51 fits into a corresponding opening 56 in the housing wall. The part 57 of side wall 52 protruding over the lid fits into a recess 58 in the housing wall.
(78) The shown versions, in the case of which the second roller is driven via toothed wheels, adjusting of the rollers following the assembly of the roller carrier is required. This is done for example with the help of the toothed wheels.
(79) In the embodiment variant of the quick-change device 59 of
(80) The use of three-roller embossing devices has been known at least since the year 2000 from WO 00/69622 of the same applicant.