CA2208087A1 - A method for impressing directly on paper holograms, kinetic holograms, diffraction patterns or microengravings producing other optical effects - Google Patents
A method for impressing directly on paper holograms, kinetic holograms, diffraction patterns or microengravings producing other optical effectsInfo
- Publication number
- CA2208087A1 CA2208087A1 CA002208087A CA2208087A CA2208087A1 CA 2208087 A1 CA2208087 A1 CA 2208087A1 CA 002208087 A CA002208087 A CA 002208087A CA 2208087 A CA2208087 A CA 2208087A CA 2208087 A1 CA2208087 A1 CA 2208087A1
- Authority
- CA
- Canada
- Prior art keywords
- paper
- roller
- microengravings
- embossing
- rollers
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 238000000034 method Methods 0.000 title claims abstract description 29
- 230000003287 optical effect Effects 0.000 title claims description 6
- 238000004049 embossing Methods 0.000 claims abstract description 34
- 230000008569 process Effects 0.000 claims abstract description 12
- 238000010438 heat treatment Methods 0.000 claims description 18
- 238000001816 cooling Methods 0.000 claims description 10
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 6
- 229920000742 Cotton Polymers 0.000 claims description 4
- 239000004744 fabric Substances 0.000 claims description 4
- 239000000123 paper Substances 0.000 description 59
- 239000004809 Teflon Substances 0.000 description 4
- 229920006362 Teflon® Polymers 0.000 description 4
- 239000012530 fluid Substances 0.000 description 4
- 239000011159 matrix material Substances 0.000 description 3
- 238000007639 printing Methods 0.000 description 3
- 229910000760 Hardened steel Inorganic materials 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000007645 offset printing Methods 0.000 description 2
- 239000004743 Polypropylene Substances 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 239000003292 glue Substances 0.000 description 1
- 239000002655 kraft paper Substances 0.000 description 1
- 229920000728 polyester Polymers 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- -1 polypropylene Polymers 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 229920000915 polyvinyl chloride Polymers 0.000 description 1
- 238000002203 pretreatment Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B31—MAKING ARTICLES OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER; WORKING PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
- B31F—MECHANICAL WORKING OR DEFORMATION OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
- B31F1/00—Mechanical deformation without removing material, e.g. in combination with laminating
- B31F1/07—Embossing, i.e. producing impressions formed by locally deep-drawing, e.g. using rolls provided with complementary profiles
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B44—DECORATIVE ARTS
- B44C—PRODUCING DECORATIVE EFFECTS; MOSAICS; TARSIA WORK; PAPERHANGING
- B44C1/00—Processes, not specifically provided for elsewhere, for producing decorative surface effects
- B44C1/24—Pressing or stamping ornamental designs on surfaces
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B31—MAKING ARTICLES OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER; WORKING PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
- B31F—MECHANICAL WORKING OR DEFORMATION OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
- B31F2201/00—Mechanical deformation of paper or cardboard without removing material
- B31F2201/07—Embossing
- B31F2201/0707—Embossing by tools working continuously
- B31F2201/0715—The tools being rollers
- B31F2201/0723—Characteristics of the rollers
- B31F2201/0728—Material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B31—MAKING ARTICLES OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER; WORKING PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
- B31F—MECHANICAL WORKING OR DEFORMATION OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
- B31F2201/00—Mechanical deformation of paper or cardboard without removing material
- B31F2201/07—Embossing
- B31F2201/0707—Embossing by tools working continuously
- B31F2201/0715—The tools being rollers
- B31F2201/0723—Characteristics of the rollers
- B31F2201/0733—Pattern
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B31—MAKING ARTICLES OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER; WORKING PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
- B31F—MECHANICAL WORKING OR DEFORMATION OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
- B31F2201/00—Mechanical deformation of paper or cardboard without removing material
- B31F2201/07—Embossing
- B31F2201/0707—Embossing by tools working continuously
- B31F2201/0715—The tools being rollers
- B31F2201/0723—Characteristics of the rollers
- B31F2201/0738—Cross sectional profile of the embossments
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B31—MAKING ARTICLES OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER; WORKING PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
- B31F—MECHANICAL WORKING OR DEFORMATION OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
- B31F2201/00—Mechanical deformation of paper or cardboard without removing material
- B31F2201/07—Embossing
- B31F2201/0784—Auxiliary operations
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
- G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
- G03H1/02—Details of features involved during the holographic process; Replication of holograms without interference recording
- G03H1/0276—Replicating a master hologram without interference recording
- G03H1/028—Replicating a master hologram without interference recording by embossing
Abstract
The impression of the microengravings is achieved by means of an embossing process wherein the paper is passed through an embossing group (17, 18), consisting of an embossing cylinder (17) carrying said microengravings and a counterthrust cylinder (18), said process being carried out, after humidification of the paper, at a temperature and a pressure on the paper passing between said cylinders included within the ranges of 90-220 ~C and 20-120 kg/mm2 respectively, preferably 130-170 ~C and 40-100 kg/mm2 respectively.
Description
W O96/19357 PCTAI~5/00222 Method for embosslng paper The present invention relates to a method for impressing directly on paper holograms, kinetic holograms, diffraction patterns or micro-engravings producing other optical effects.
In order to permanently transfer optical microengravings (i.e.
microengravings of the above-mentioned type) from a type plate to paper sheets it is usually necessary to provide a pre-treatment of the paper consisting of a coating of the paper with a film of a material (such as PVC, polyester, polypropylene, polythene, coating, etc.) suitable to receive and permanently retain the microengravings present (in low relief and/or high relief) on the plate.
In fact, it is usually excluded that it is possible to transfer directly said microengravings onto common paper (i.e. not pre-treated as above) due both to the deformability (at micrometric level) of paper in time and to the surface micro-roughness usually found in paper sheets, caused by the fibrous structure of paper, which roughness is not compatible with the degree of resolution of the microengravings to be transferred, which can range from about 120 lines/mm to about 5000 lines/mm.
The present invention is aimed at overcoming said prejudice on the impossibility of impressing microengravings on common untreated paper by providing a method for impressing microengravings on common paper, which not only is simpler and cheaper than the conventional methods for impr~ssir,g mic,oengravings on a pre-treated paper substrate but also gives further advantages such as making available:
- common paper which is personalized or decorated with the above-mentioned type of microengravings;
30 - personalized or decorated paper as above which lends itself to be used as writing paper and printing paper (for offset, copperplate, typographic, serigraphic, rotogravure, xerographic, etc., printing);
- personalized or decorated paper as above for documents which are to be protected from forgery or guaranteed for originality.
According to the method of the present invention for impressing directly on paper holograms, kinetic holograms, diffraction patterns or W O96/19357 PCTA1~5/00222 microengravings producing other optical effects, the impression of said microengravings is achieved by means of an embossing process wherein the paper is passed between a pair of embossing cylinders, namely an embossing cylinder, carrying said microengravings, and a counterthrust 5 cylinder, said process being carried out, after humidification of the paper, at a temperature and a pressure on the paper passing between said cylinders respectively within the ranges of 90-220~C and 20-120 kg/mm2, preferably 130-170~C and 40-100 kg/mmZ.
The characteristics of the invention will be apparent from the 10 following description and from the annexed drawings which illustrate non-limiting examples of embodiments, whose figures show:
Fia.1: a machine for embossing paper in reels according to the present method;
Fiq.2 an enlarged detail of fig.1 relating to the paper humidifier;
Fia.3: a machine for embossing paper in sheets according to the present method.
Fig.1 shows an example of a machine for embossing paper in reels according to the present invention.
The structural and functional characteristics of the machine follow those of a conventional embossing machine with sul.slanlial differences regarding the conditions (temperature and pressure) under which the embossing process is carried out and regarding the presence of a paper humidifier upstream from the embossing group consisting of the embossing cylinder and the relevant counterthrust cylinder.
In fig.1, the meaning of the various members is the following:
1: reel of common paper for feeding the machine.
In order to permanently transfer optical microengravings (i.e.
microengravings of the above-mentioned type) from a type plate to paper sheets it is usually necessary to provide a pre-treatment of the paper consisting of a coating of the paper with a film of a material (such as PVC, polyester, polypropylene, polythene, coating, etc.) suitable to receive and permanently retain the microengravings present (in low relief and/or high relief) on the plate.
In fact, it is usually excluded that it is possible to transfer directly said microengravings onto common paper (i.e. not pre-treated as above) due both to the deformability (at micrometric level) of paper in time and to the surface micro-roughness usually found in paper sheets, caused by the fibrous structure of paper, which roughness is not compatible with the degree of resolution of the microengravings to be transferred, which can range from about 120 lines/mm to about 5000 lines/mm.
The present invention is aimed at overcoming said prejudice on the impossibility of impressing microengravings on common untreated paper by providing a method for impressing microengravings on common paper, which not only is simpler and cheaper than the conventional methods for impr~ssir,g mic,oengravings on a pre-treated paper substrate but also gives further advantages such as making available:
- common paper which is personalized or decorated with the above-mentioned type of microengravings;
30 - personalized or decorated paper as above which lends itself to be used as writing paper and printing paper (for offset, copperplate, typographic, serigraphic, rotogravure, xerographic, etc., printing);
- personalized or decorated paper as above for documents which are to be protected from forgery or guaranteed for originality.
According to the method of the present invention for impressing directly on paper holograms, kinetic holograms, diffraction patterns or W O96/19357 PCTA1~5/00222 microengravings producing other optical effects, the impression of said microengravings is achieved by means of an embossing process wherein the paper is passed between a pair of embossing cylinders, namely an embossing cylinder, carrying said microengravings, and a counterthrust 5 cylinder, said process being carried out, after humidification of the paper, at a temperature and a pressure on the paper passing between said cylinders respectively within the ranges of 90-220~C and 20-120 kg/mm2, preferably 130-170~C and 40-100 kg/mmZ.
The characteristics of the invention will be apparent from the 10 following description and from the annexed drawings which illustrate non-limiting examples of embodiments, whose figures show:
Fia.1: a machine for embossing paper in reels according to the present method;
Fiq.2 an enlarged detail of fig.1 relating to the paper humidifier;
Fia.3: a machine for embossing paper in sheets according to the present method.
Fig.1 shows an example of a machine for embossing paper in reels according to the present invention.
The structural and functional characteristics of the machine follow those of a conventional embossing machine with sul.slanlial differences regarding the conditions (temperature and pressure) under which the embossing process is carried out and regarding the presence of a paper humidifier upstream from the embossing group consisting of the embossing cylinder and the relevant counterthrust cylinder.
In fig.1, the meaning of the various members is the following:
1: reel of common paper for feeding the machine.
2: spare reel of common paper.
3, 4, 5, 6, 7: idle rollers.
8: roller, preferably coated with teflon or rubber, for driving and pre-heating the paper strip.
9: roller, also preferably coated with teflon or rubber, for driving and cooling the paper strip.
10, 1 1, 12: idle rollers elastically biased against rollers 8 and 9 respectively in order to assure the friction driving of the paper strip by roilers 8 and 9.
13, 14: idle rollers for tensioning the paper strip, which are capable of W O96tl9357 PCT~I~5/00222 shifting their axis so as to keep the passing strip in conditions of proper tension.
15: humidifying group.
16: cooling roller.
17, 18: embossing group which consists of an embossing cylinder 17 carrying on its cylindrical surface the matrix of the microengravings to be impressed on the paper (the microengravings may be engraved directly on the embossing cylinder or on a thin type plate fixed onto the cylinder), and of an idle counterthrust cylinder 18 exerting on cylinder 17 an adequate pressure.
19: pre-heating unit, which is provided with infrared lamps or operated by gas and capable of shifting vertically for moving closer/farther with respect to the passing strip in order to adjust the pre-heating temperature of the strip.
20: stripwinding reel.
21: arm which supports reel 20 and is capable of oscillating around its lower end, the angle of inclination thereof being a function of the diameter D of the winding reel (which diameter is smallest at the beginning of the process and largest at the end).
The operation of the machine can be described as follows.
During the operation, the paper strip unwinds from reel 1 and passes first on rollers 3, 13, 11 and then on cylinder 8 where it undergoes a first pre-heating and a humidification by means of group 15, which gives paper a degree of humidity around 60-80% of relative humidity (in particular a degree of humidity equal to 70% according to a preferred embodiment).
After coming out from roller 8, the paper strip passes under unit 19 where it undergoes a further pre-heating and then passes between the two cylinders of the embossing group where it receives the impression of the microengravings present on the embossing cylinder while undergoing a strong stretching action produced by both the high pressure exerted by cylinder 18 and the temperature of the two cylinders 17, 18. After coming out from the embossing group, the strip undergoes a first cooling by passing on cylinder 16 and then, after passing on rollers 5, 6, 7, 14 and 12, a last cooling on cylinder 9 to a temperature substantially equal to room temperature, after which it is wound on reel 20 abutting against said roller 9.
W O96/19357 PCTA1~5/00222 Cylinder 17 must have the characteristics usually required for embossing cylinders, namely it must be made from ground and lapped hardened steel of high surface resilience, with a very high degree of surface finish, such that the cylinder surface has a degree of linearity (i.e.
of approximation of a straight line), along any generatrix of the cylindrical surface, close to the order of magnitude of the resolution of the microengravings on the plate. An acceptable value of said degree of linearity could be, for example, around 2000 lines per mm.
Cylinder 18, also made from ground and lapped hardened steel, is idle around its axis so that, when operating, it can be driven by the rotation of the upper cylinder 17. It exerts against cylinder 17 a pressure of a quite high value, to be selected in the range from 20 kg/mm2 to 120 kg/mm2 (said pressure is selected around 50 kg/mm2 according to a preferred embodiment).
When operating, both cylinder 17 and 18 are heated at a temperature such as to assure that the paper of the document passing under the plate reaches a temperature between 90 and 220~C (said temperature is selected around 1 50~C according to a preferred embodiment).
Said temperature of cylinders 17, 18 (as well as that of cylinder 8 and unit 19) shall be selected according to the operating speed (strip moving speed), in that higher speeds require higher temperatures of the cylinders (and of unit 19) in order to achieve the same paper temperature.
For a paper temperature of about 150~C and an operating speed around 60 m/min, the temperature of cylinders 17, 18 should be around 1 50~C.
The heating of cylinders 8, 17 and 18 may be obtained by means of a fluid circulating therein or through an eiectric resistor.
Also the cooling of cylinders 9 and 16 may be obtained by means of a fluid (e.g. water) circulating therein.
Fig.2 shows an enlargement of group 15 of fig.1. This group has structural and functional characteristics like those of similar units used in other technological fields, for example in offset printing. It is made up of a water tank 22 wherein a continuously rotating roller 23 is partially immersed. Idle roller 24 has an oscillating axis such that it is taken from a position of temporary contact with roller 23 (e.g. for a portion of a W O 96/19357 PCT~1~5/00222 revolution of 24) to a position of longer contact with roller 25 (e.g. for a complete revolution). The axis of roller 25, which is also idle, is in turn provided with a slight oscillating motion along a plane parallel to the plane passing through the axes of rollers 26 and 27 (which are also idle and 5 permanently in contact with the passing strip), so that roller 2~ is alternately in contact with said rollers 26 and 27 and can evenly distribute thereon the humidity received from 24.
The surface of the rollers of group 15 is preferably coated with a material easily soaked up with water, for example a velvet-like cotton 10 fabric.
The correct humidity of the paper strip passing is adjusted by means of a humidity detector (not shown) positioned in contact with the strip coming out from group 15, which adjusts the duration of the temporary contact of roller 24 on roller 23 according to the detected humidity.
At the end of the process, the strip wound on reel 20 retains the impressed mlcroengravings transferred from the embossing cylinder. The surprising possibility of permanent transfer of the microengravings on the paper strip can be explained by the fact that due to the humidification process and the subsequent heating under a high pressure, the paper 20 undergoes a compacting and stretching process which results in a considerable reduction of its surface irregularity and deformability.
It may be desirable that the microengravings transferred on the paper (and consequently their optical effect) can not resist (or on the contrary can resist, according to needs) possible alterations or counterfeiting of the 25 paper (humidification, erasing, etc.).
Whenever it is required that the impressed microengravings can resist possible humidifications, it will be necessary to use a refined paper charged with glue such as the paper employed in the manufacturing of kraft paper, of paper for nautical handbooks, etc. When it is desirable, on 30 the contrary, to have microengravings of opposite characteristic, it will be necess~ry to use common paper (of hygroscopic nature).
As far as the possibility of resisting possible erasures is concerned, it should be considered that the printing matrix can be made with all engravings in low-relief or in high-relief or with engravings partly in low-35 relief and partly in high-relief possibly distributed in different areas (i.e.
some portions of the plate have only high-relief engravings and other W O96119357 PCT~1~5/00222 portions only low-relief engravings).
The above-mentioned possibility allows the manufacturing of microengraved paper which can (or can not) resist erasures. In fact, the microengravings impressed on paper in low-relief can resist erasures and 5 the surface wear which paper undergoes in time, whereas those impressed in high-relief are erased at any counterfeiting attempt, this latter characteristic being very important whenever the paper is to be used for issuing documents whose originality is to be assured and protected from forgery (such as for example paper securities, bank cheques, etc.).
Fig.3 shows an example of an embossing machine for paper in sheets according to the present method.
In this figure the meaning of the various members is the following:
30, 31: inlet and outlet sheet trays.
32: tube for picking and feeding the sheets, provided with suction mouths, which is part of a sheet-feeder device (not shown in the figure) quite similar to a suction sheet-feeder device for conventional offset printing.
33, 49: rotating rollers for feeding incoming and outgoing sheets respectively.
34: planes for sheet sliding.
35, 36: a pair of rollers for humidifying and feeding the paper, with 35 idle and driven into rotation by the underlying roller 36, and 36 which provides not only the sheet feeding but its humidification as well. To this purpose, 36 is coated with a fabric (e.g. cotton) which is soaked up with water by means of a humidification group 15' quite similar to, in structure and operation, group 15 of fig.1.
37/38, 39/40: pairs of rollers for pre-heating and feeding the paper, said rollers being preferably coated with a rubber or teflon layer and provided with a rotating motion.
41/42, 43144, 45/46: pairs of rollers for cooling and feeding the paper, also preferably coated with a rubber or teflon layer.
47, 48: embossing group consisting of an embossing cylinder 47 carrying on its cylindrical surface the matrix of the microengravings to be impressed on the paper, and of an idle counterthrust cylinder 48 exerting on cylinder 47 an adequate pressure.
50: plane for sheets sliding and pre-heating, with heating obtained by W O96/19357 PCTAI~5/00222 means of infrared lamps or gas.
Likewise in the case of the machine of fig.1, the heating of cylinders 37-40 and 47, 48 may be achieved through a fluid circulating therein or by means of electric resistors. Also the cooling of cylinders 41-46 may be 5 achieved through a circulating fluid.
The machine operation is quite similar to that of the machine of fig.1, also with respect to the conditions of paper humidification and the temperature and pressure on the paper when it passes through the embosslng group.
8: roller, preferably coated with teflon or rubber, for driving and pre-heating the paper strip.
9: roller, also preferably coated with teflon or rubber, for driving and cooling the paper strip.
10, 1 1, 12: idle rollers elastically biased against rollers 8 and 9 respectively in order to assure the friction driving of the paper strip by roilers 8 and 9.
13, 14: idle rollers for tensioning the paper strip, which are capable of W O96tl9357 PCT~I~5/00222 shifting their axis so as to keep the passing strip in conditions of proper tension.
15: humidifying group.
16: cooling roller.
17, 18: embossing group which consists of an embossing cylinder 17 carrying on its cylindrical surface the matrix of the microengravings to be impressed on the paper (the microengravings may be engraved directly on the embossing cylinder or on a thin type plate fixed onto the cylinder), and of an idle counterthrust cylinder 18 exerting on cylinder 17 an adequate pressure.
19: pre-heating unit, which is provided with infrared lamps or operated by gas and capable of shifting vertically for moving closer/farther with respect to the passing strip in order to adjust the pre-heating temperature of the strip.
20: stripwinding reel.
21: arm which supports reel 20 and is capable of oscillating around its lower end, the angle of inclination thereof being a function of the diameter D of the winding reel (which diameter is smallest at the beginning of the process and largest at the end).
The operation of the machine can be described as follows.
During the operation, the paper strip unwinds from reel 1 and passes first on rollers 3, 13, 11 and then on cylinder 8 where it undergoes a first pre-heating and a humidification by means of group 15, which gives paper a degree of humidity around 60-80% of relative humidity (in particular a degree of humidity equal to 70% according to a preferred embodiment).
After coming out from roller 8, the paper strip passes under unit 19 where it undergoes a further pre-heating and then passes between the two cylinders of the embossing group where it receives the impression of the microengravings present on the embossing cylinder while undergoing a strong stretching action produced by both the high pressure exerted by cylinder 18 and the temperature of the two cylinders 17, 18. After coming out from the embossing group, the strip undergoes a first cooling by passing on cylinder 16 and then, after passing on rollers 5, 6, 7, 14 and 12, a last cooling on cylinder 9 to a temperature substantially equal to room temperature, after which it is wound on reel 20 abutting against said roller 9.
W O96/19357 PCTA1~5/00222 Cylinder 17 must have the characteristics usually required for embossing cylinders, namely it must be made from ground and lapped hardened steel of high surface resilience, with a very high degree of surface finish, such that the cylinder surface has a degree of linearity (i.e.
of approximation of a straight line), along any generatrix of the cylindrical surface, close to the order of magnitude of the resolution of the microengravings on the plate. An acceptable value of said degree of linearity could be, for example, around 2000 lines per mm.
Cylinder 18, also made from ground and lapped hardened steel, is idle around its axis so that, when operating, it can be driven by the rotation of the upper cylinder 17. It exerts against cylinder 17 a pressure of a quite high value, to be selected in the range from 20 kg/mm2 to 120 kg/mm2 (said pressure is selected around 50 kg/mm2 according to a preferred embodiment).
When operating, both cylinder 17 and 18 are heated at a temperature such as to assure that the paper of the document passing under the plate reaches a temperature between 90 and 220~C (said temperature is selected around 1 50~C according to a preferred embodiment).
Said temperature of cylinders 17, 18 (as well as that of cylinder 8 and unit 19) shall be selected according to the operating speed (strip moving speed), in that higher speeds require higher temperatures of the cylinders (and of unit 19) in order to achieve the same paper temperature.
For a paper temperature of about 150~C and an operating speed around 60 m/min, the temperature of cylinders 17, 18 should be around 1 50~C.
The heating of cylinders 8, 17 and 18 may be obtained by means of a fluid circulating therein or through an eiectric resistor.
Also the cooling of cylinders 9 and 16 may be obtained by means of a fluid (e.g. water) circulating therein.
Fig.2 shows an enlargement of group 15 of fig.1. This group has structural and functional characteristics like those of similar units used in other technological fields, for example in offset printing. It is made up of a water tank 22 wherein a continuously rotating roller 23 is partially immersed. Idle roller 24 has an oscillating axis such that it is taken from a position of temporary contact with roller 23 (e.g. for a portion of a W O 96/19357 PCT~1~5/00222 revolution of 24) to a position of longer contact with roller 25 (e.g. for a complete revolution). The axis of roller 25, which is also idle, is in turn provided with a slight oscillating motion along a plane parallel to the plane passing through the axes of rollers 26 and 27 (which are also idle and 5 permanently in contact with the passing strip), so that roller 2~ is alternately in contact with said rollers 26 and 27 and can evenly distribute thereon the humidity received from 24.
The surface of the rollers of group 15 is preferably coated with a material easily soaked up with water, for example a velvet-like cotton 10 fabric.
The correct humidity of the paper strip passing is adjusted by means of a humidity detector (not shown) positioned in contact with the strip coming out from group 15, which adjusts the duration of the temporary contact of roller 24 on roller 23 according to the detected humidity.
At the end of the process, the strip wound on reel 20 retains the impressed mlcroengravings transferred from the embossing cylinder. The surprising possibility of permanent transfer of the microengravings on the paper strip can be explained by the fact that due to the humidification process and the subsequent heating under a high pressure, the paper 20 undergoes a compacting and stretching process which results in a considerable reduction of its surface irregularity and deformability.
It may be desirable that the microengravings transferred on the paper (and consequently their optical effect) can not resist (or on the contrary can resist, according to needs) possible alterations or counterfeiting of the 25 paper (humidification, erasing, etc.).
Whenever it is required that the impressed microengravings can resist possible humidifications, it will be necessary to use a refined paper charged with glue such as the paper employed in the manufacturing of kraft paper, of paper for nautical handbooks, etc. When it is desirable, on 30 the contrary, to have microengravings of opposite characteristic, it will be necess~ry to use common paper (of hygroscopic nature).
As far as the possibility of resisting possible erasures is concerned, it should be considered that the printing matrix can be made with all engravings in low-relief or in high-relief or with engravings partly in low-35 relief and partly in high-relief possibly distributed in different areas (i.e.
some portions of the plate have only high-relief engravings and other W O96119357 PCT~1~5/00222 portions only low-relief engravings).
The above-mentioned possibility allows the manufacturing of microengraved paper which can (or can not) resist erasures. In fact, the microengravings impressed on paper in low-relief can resist erasures and 5 the surface wear which paper undergoes in time, whereas those impressed in high-relief are erased at any counterfeiting attempt, this latter characteristic being very important whenever the paper is to be used for issuing documents whose originality is to be assured and protected from forgery (such as for example paper securities, bank cheques, etc.).
Fig.3 shows an example of an embossing machine for paper in sheets according to the present method.
In this figure the meaning of the various members is the following:
30, 31: inlet and outlet sheet trays.
32: tube for picking and feeding the sheets, provided with suction mouths, which is part of a sheet-feeder device (not shown in the figure) quite similar to a suction sheet-feeder device for conventional offset printing.
33, 49: rotating rollers for feeding incoming and outgoing sheets respectively.
34: planes for sheet sliding.
35, 36: a pair of rollers for humidifying and feeding the paper, with 35 idle and driven into rotation by the underlying roller 36, and 36 which provides not only the sheet feeding but its humidification as well. To this purpose, 36 is coated with a fabric (e.g. cotton) which is soaked up with water by means of a humidification group 15' quite similar to, in structure and operation, group 15 of fig.1.
37/38, 39/40: pairs of rollers for pre-heating and feeding the paper, said rollers being preferably coated with a rubber or teflon layer and provided with a rotating motion.
41/42, 43144, 45/46: pairs of rollers for cooling and feeding the paper, also preferably coated with a rubber or teflon layer.
47, 48: embossing group consisting of an embossing cylinder 47 carrying on its cylindrical surface the matrix of the microengravings to be impressed on the paper, and of an idle counterthrust cylinder 48 exerting on cylinder 47 an adequate pressure.
50: plane for sheets sliding and pre-heating, with heating obtained by W O96/19357 PCTAI~5/00222 means of infrared lamps or gas.
Likewise in the case of the machine of fig.1, the heating of cylinders 37-40 and 47, 48 may be achieved through a fluid circulating therein or by means of electric resistors. Also the cooling of cylinders 41-46 may be 5 achieved through a circulating fluid.
The machine operation is quite similar to that of the machine of fig.1, also with respect to the conditions of paper humidification and the temperature and pressure on the paper when it passes through the embosslng group.
Claims (9)
1. A method for impressing directly on paper microengravings which reproduce holograms, kinetic holograms, diffraction patterns or microengravings producing other optical effects, characterized in that the impression of said microengravings is achieved through an embossing process wherein the paper is passed through an embossing group consisting of an embossing cylinder (17, 47) carrying said microengravings and a counterthrust cylinder (18, 48), said process being carried out, after humidification of the paper, at a temperature and a pressure on the paper passing between said cylinders (17, 18; 47, 48) included within the ranges of 90-220°C and 20-120 kg/mm2 respectively, preferably 130-170°C and 40-100 kg/mm2 respectively.
2. The method according to claim 1, characterized in that the humidification of the paper gives it a degree of humidity between 60 and 80% of relative humidity.
3. The method according to claim 1, characterized in that the paper coming out from the embossing group (17, 18; 47, 48) is subjected to cooling to a temperature substantially equal to room temperature.
4. The method according to claim 1, characterized in that the temperature of the paper passing through the embossing group (17, 18;
47, 48) is reached through a first heating step prior to the inlet between the cylinders (17, 18; 47, 48) and a second heating step carried out by the cylinders (17, 18; 47, 48).
47, 48) is reached through a first heating step prior to the inlet between the cylinders (17, 18; 47, 48) and a second heating step carried out by the cylinders (17, 18; 47, 48).
5. The method according to claim 4, characterized in that the temperature, pressure and humidity of the paper passing through the embossing group (17, 18; 47, 48) are respectively around 150°C, 50 kg/mm2 and 70% of relative humidity.
6. The method according to claim 4, wherein the paper on which the microengravings are impressed is in the form of a strip unwinding from a feed reel (1), characterized in that the paper strip, prior to passing through the embossing group (17, 18), first passes on a first cylinder (8) where it undergoes the above-mentioned humidification and a first pre-heating at the same time, and then passes near an infrared or gas-operated pre-heating unit (19), and further characterized in that the strip coming out from the embossing group (17, 18), prior to being wound on a rewinding reel (20), passes in sequence on a second (16) and third cylinders (9) where it undergoes a first and respectively second cooling.
7. The method according to claim 6, characterized in that the humidification of the paper is obtained by means of a group of five rollers consisting of a first (26) and second (27) idle rollers abutting against a length of strip passing on the above-mentioned first cylinder (8), a third roller (23), continuously rotating and partially immersed in water, a fourth idle roller (24) contacting alternately the third (23) roller and a fifth roller(25) so as to transfer the humidity from the third roller (23) to the fifth roller (25), the latter contacting alternately the first (26) and second (27) rollers so as to transfer thereto the humidity received from the fourth roller (24), said rollers (23, 24, 25, 26, 27) having their surface coated with velvet-like cotton fabric.
8. The method according to claim 4, wherein the paper on which the microengravings are impressed is in the form of separate sheets, characterized in that a single sheet, prior to passing through the embossing group (47, 48), passes between a first pair of cylinders (35, 36) where it undergoes the humidification process, then passes between at least a second pair of cylinders (37, 38) where it undergoes a first heating, and finally passes near an infrared or gas-operated pre-heating unit (50), where it undergoes a second heating, and further characterized in that the above-mentioned sheet coming out from the embossing group (47, 48) passes between at least a third pair of cylinders (41, 42) where it undergoes a cooling.
9. The method according to claim 8, characterized in that the humidification of the sheet is obtained by means of a group of five rollers consisting of a first (26) and second (27) idle rollers abutting against a length of strip passing on the above-mentioned first cylinder (8), a third roller (23), continuously rotating, partially immersed in water, a fourth idle roller (24) contacting alternately the third (23) roller and a fifth roller (25)so as to transfer the humidity from the third roller (23) to the fifth roller (25), the latter contacting alternately the first (26) and second (27) rollers so as to transfer thereto the humidity received from the fourth roller (24), said rollers (23, 24, 25, 26, 27) having their surface coated with velvet-like cotton fabric.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IT94MI002583A IT1275697B1 (en) | 1994-12-20 | 1994-12-20 | METHOD FOR PRINTING HOLOGRAMS, KINOGRAMS, DIFFRACTION RETICLES OR MICRO-ENGRAVINGS DIRECTLY ON PAPER |
| ITMI94A002583 | 1994-12-20 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2208087A1 true CA2208087A1 (en) | 1996-06-27 |
Family
ID=11370031
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002208087A Abandoned CA2208087A1 (en) | 1994-12-20 | 1995-12-19 | A method for impressing directly on paper holograms, kinetic holograms, diffraction patterns or microengravings producing other optical effects |
Country Status (28)
| Country | Link |
|---|---|
| US (1) | US5862750A (en) |
| EP (1) | EP0799139B1 (en) |
| JP (1) | JPH10511321A (en) |
| CN (1) | CN1170386A (en) |
| AR (1) | AR000377A1 (en) |
| AT (1) | ATE180214T1 (en) |
| AU (1) | AU704308B2 (en) |
| BR (1) | BR9510285A (en) |
| CA (1) | CA2208087A1 (en) |
| CO (1) | CO4480768A1 (en) |
| DE (1) | DE69509796T2 (en) |
| DK (1) | DK0799139T3 (en) |
| DZ (1) | DZ1949A1 (en) |
| EG (1) | EG20698A (en) |
| ES (1) | ES2134510T3 (en) |
| FI (1) | FI972547A (en) |
| GR (1) | GR3030979T3 (en) |
| HU (1) | HUT77594A (en) |
| IL (1) | IL116179A (en) |
| IT (1) | IT1275697B1 (en) |
| MA (1) | MA23750A1 (en) |
| NO (1) | NO972838L (en) |
| PE (1) | PE14397A1 (en) |
| TN (1) | TNSN95121A1 (en) |
| TR (1) | TR199501604A2 (en) |
| UY (1) | UY24124A1 (en) |
| WO (1) | WO1996019357A1 (en) |
| ZA (1) | ZA9510325B (en) |
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| US10913234B2 (en) | 2014-08-29 | 2021-02-09 | Clopay Plastic Products Company, Inc. | Embossed matte and glossy plastic film and methods of making same |
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| US6586661B1 (en) * | 1997-06-12 | 2003-07-01 | North Carolina State University | Regulation of quinolate phosphoribosyl transferase expression by transformation with a tobacco quinolate phosphoribosyl transferase nucleic acid |
| DE19756094A1 (en) * | 1997-12-17 | 1999-06-24 | Winkler Duennebier Kg Masch | Method for forming a die mold and embossing device for carrying out the method |
| US6694872B1 (en) | 1999-06-18 | 2004-02-24 | Holographic Label Converting, Inc. | In-line microembossing, laminating, printing, and diecutting |
| US6694873B1 (en) | 1999-06-18 | 2004-02-24 | Holographic Label Converting, Inc. | Microembosser for faster production of holographic labels |
| CA2324786C (en) | 1999-11-01 | 2014-02-25 | Fort James Corporation | Multi-ply absorbent paper product having impressed pattern |
| US6733626B2 (en) * | 2001-12-21 | 2004-05-11 | Georgia Pacific Corporation | Apparatus and method for degrading a web in the machine direction while preserving cross-machine direction strength |
| DE19962294A1 (en) * | 1999-12-23 | 2001-09-06 | Metsae Tissue Oyj Espoo | Tissue- and / or tissue-like material and method for its production |
| FI116086B (en) * | 2000-06-08 | 2005-09-15 | Avantone Oy | Check-marked paper or cardboard product and check-marked packaging |
| CN1093032C (en) * | 2000-06-22 | 2002-10-23 | 汕头市金时印刷有限公司 | Method of forming text and picture on the surface of paper product and the paper product obtained thereby |
| DE60121603T2 (en) * | 2000-08-30 | 2007-06-21 | North Carolina State University | TRANSGENIC PLANTS CONTAINING MOLECULAR DECOYS THAT CHANGE THE PROTEIN CONTENT |
| EP1406518A4 (en) * | 2001-06-08 | 2006-03-29 | Vector Tobacco Ltd | Modifying nicotine and nitrosamine levels in tobacco |
| EP2050869B1 (en) | 2002-01-29 | 2014-12-31 | Valmet Technologies, Inc. | Safety paper |
| AU2003230833A1 (en) * | 2002-04-09 | 2003-10-27 | Vector Tobacco Ltd. | Tobacco having reduced nicotine and nitrosamines |
| WO2005041151A2 (en) * | 2003-10-02 | 2005-05-06 | Vector Tobacco Ltd. | Tobacco product labeling system |
| DE502005009665D1 (en) * | 2004-06-22 | 2010-07-15 | Boegli Gravures Sa | Apparatus and method for satinizing and embossing flat material |
| FI20045295A (en) * | 2004-08-13 | 2006-02-14 | Avantone Oy | Embossing device and method for adjusting an embossing device |
| FI20045293A (en) * | 2004-08-13 | 2006-02-14 | Avantone Oy | Apparatus and method for producing a diffractive microstructure |
| US20070150753A1 (en) * | 2005-12-02 | 2007-06-28 | Shmuel Silverman | Information protection using a printed electronic circuit and mechanical impression |
| PH12012500300A1 (en) * | 2006-01-30 | 2007-08-09 | Univ Georgia State Res Found | Induction and stabilization of enzymatic activity in microorganisms |
| FI20065407A0 (en) * | 2006-06-14 | 2006-06-14 | Avantone Oy | Hard forgery hologram |
| CA2617812C (en) * | 2007-01-12 | 2013-07-09 | Cascades Canada Inc. | Wet embossed paperboard and method and apparatus for manufacturing same |
| US8012309B2 (en) * | 2007-01-12 | 2011-09-06 | Cascades Canada Ulc | Method of making wet embossed paperboard |
| ATE517736T1 (en) * | 2007-12-20 | 2011-08-15 | Sca Hygiene Prod Gmbh | METHOD AND DEVICE FOR PRODUCING A PRINTED AND EMBOSSED WEB |
| US20140141181A1 (en) * | 2012-11-19 | 2014-05-22 | Munzer Makansi | Process for forming rainbow and hologram images on papers |
| EP3037253A1 (en) | 2014-12-22 | 2016-06-29 | Boegli-Gravures S.A. | Micro-embossing |
| IT201700065732A1 (en) * | 2017-06-14 | 2018-12-14 | Gambini Spa | DEVICE FOR PAPER MICRO-EMBOSSING AND LINE FOR PAPER PROCESSING INCLUDING THIS DEVICE. |
| JP6977441B2 (en) * | 2017-09-21 | 2021-12-08 | コニカミノルタ株式会社 | Paper humidifiers, image forming systems and programs |
| JP6992373B2 (en) * | 2017-09-29 | 2022-01-13 | コニカミノルタ株式会社 | Paper humidifiers, image forming systems and programs |
| CN111873554A (en) * | 2020-07-09 | 2020-11-03 | 江苏联美工业标识科技有限公司 | Embossing device for applique production |
| CN112848491B (en) * | 2020-12-27 | 2023-01-13 | 海默尼药业股份有限公司 | Medicine packaging box production device with stacking function |
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| US3024154A (en) * | 1958-04-04 | 1962-03-06 | Carpenter L E Co | Method and apparatus for embossing and printing thermoplastic film and the product thereof |
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| US3932245A (en) * | 1969-05-02 | 1976-01-13 | Gaf Corporation | Mechanical embossing of foamed sheet material |
| GB1447077A (en) * | 1973-11-07 | 1976-08-25 | Fei M | Embossing stripform material |
| US4135962A (en) * | 1976-09-27 | 1979-01-23 | Consolidated Cigar Corp. | Apparatus for decorating sheet material |
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| US5318807A (en) * | 1991-10-28 | 1994-06-07 | Juan Grifoll Casanovas | Process for preparing printed sheets with optical effects |
| JPH06264400A (en) * | 1993-03-05 | 1994-09-20 | Tokushu Seishi Kk | Embossed patterned paper having hand of japanese paper |
| DE69406015T2 (en) * | 1993-10-28 | 1998-03-12 | Kobs Kroyer Ingelise | METHOD AND DEVICE FOR PRODUCING A DOUBLE-SIDED EMBROIDERED FIBER TRAIN |
| CH690230A5 (en) * | 1995-03-17 | 2000-06-15 | Bobst Sa | Method and humidity control device for a material web in a printing machine. |
-
1994
- 1994-12-20 IT IT94MI002583A patent/IT1275697B1/en active IP Right Grant
-
1995
- 1995-11-28 IL IL11617995A patent/IL116179A/en not_active IP Right Cessation
- 1995-11-30 TN TNTNSN95121A patent/TNSN95121A1/en unknown
- 1995-12-05 ZA ZA9510325A patent/ZA9510325B/en unknown
- 1995-12-09 DZ DZ950132A patent/DZ1949A1/en active
- 1995-12-19 AR AR33467495A patent/AR000377A1/en unknown
- 1995-12-19 WO PCT/IT1995/000222 patent/WO1996019357A1/en active IP Right Grant
- 1995-12-19 CA CA002208087A patent/CA2208087A1/en not_active Abandoned
- 1995-12-19 CO CO95060063A patent/CO4480768A1/en unknown
- 1995-12-19 CN CN95196912A patent/CN1170386A/en active Pending
- 1995-12-19 AU AU41876/96A patent/AU704308B2/en not_active Ceased
- 1995-12-19 AT AT95940415T patent/ATE180214T1/en not_active IP Right Cessation
- 1995-12-19 DK DK95940415T patent/DK0799139T3/en active
- 1995-12-19 ES ES95940415T patent/ES2134510T3/en not_active Expired - Lifetime
- 1995-12-19 JP JP8519655A patent/JPH10511321A/en active Pending
- 1995-12-19 EP EP95940415A patent/EP0799139B1/en not_active Expired - Lifetime
- 1995-12-19 MA MA24102A patent/MA23750A1/en unknown
- 1995-12-19 DE DE69509796T patent/DE69509796T2/en not_active Expired - Fee Related
- 1995-12-19 PE PE1995287571A patent/PE14397A1/en not_active Application Discontinuation
- 1995-12-19 US US08/849,816 patent/US5862750A/en not_active Expired - Fee Related
- 1995-12-19 EG EG104195A patent/EG20698A/en active
- 1995-12-19 HU HU9800677A patent/HUT77594A/en unknown
- 1995-12-19 BR BR9510285A patent/BR9510285A/en not_active Application Discontinuation
- 1995-12-20 TR TR95/01604A patent/TR199501604A2/en unknown
- 1995-12-20 UY UY24124A patent/UY24124A1/en unknown
-
1997
- 1997-06-16 FI FI972547A patent/FI972547A/en unknown
- 1997-06-19 NO NO972838A patent/NO972838L/en unknown
-
1999
- 1999-08-17 GR GR990402056T patent/GR3030979T3/en unknown
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10913234B2 (en) | 2014-08-29 | 2021-02-09 | Clopay Plastic Products Company, Inc. | Embossed matte and glossy plastic film and methods of making same |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |