Methods of providing images on a substrate

 

The invention relates to methods for structures with variable optical effect. The method of forming patterns in the form of a diffraction grating or hologram on the substrate includes the following steps: a) providing an adhesive on a substrate, b) applying by deposition of metal powder on the adhesive, embossing patterns, producing a variable optical effect on the metal powder. The substrate is a structure in the form of a diffraction grating or hologram producing a variable optical effect, boldly embossed into the metal powder. The document is protected against forgery, includes a substrate. The method eliminates the use of flame or plasma spraying and, accordingly, high-temperature processing. 3 S. and 29 C.p. f-crystals, 1 tab., 10 Il.

The technical field to which the invention relates the Invention relates to means for securing the structure, producing a variable optical effect, and the image on the substrate.

The prior art Structure, producing a variable optical effect, such as diffraction gratings and holograms are often used for decorative purposes and for purposes of protection against forgery. In h is the identity, banknotes and so on, to enable authentication of such substrates. Traditionally, due to the subtle nature of these structures, for placing patterns on the substrate was used in the transfer process. This process involves making patterns on the carrier film, and then transferring patterns on a substrate, using the method of hot stamping or so on the Example described in the patent US-A-4913504. Other migration processes, although they are not intended for structures, producing a variable optical effect described in patents US-A-5017255, US-A-5219655, US-A-5328534 and WO-A-95/15266.

The application WO-A-97/03844 describes a method of providing a reflective characteristic element of protection against fakes on paper, protected from tampering, in which the metal is sprayed on the surface of the paper, after which he plumets, polished or processed in another way in order to convert it into a more specularly reflecting surface, or it may be molded in relief configuration. Methods for metal processing include the use of electric arc discharge methods for flame and plasma spraying, all of which have the disadvantage of having high-temperature processing. Other problems that the content that which is not to bend together with the substrate and therefore are broken, it is very difficult to control the thickness of the deposits, it is very difficult to achieve complex shapes, the number of materials that can be applied is limited. Analogous to the claimed technical solution is the patent application 85100355, Taiwan, 01.12.1996,, IPC And 44 C 27/00, which describes a method of manufacturing a decorative sheet of gold, including applying a layer of photosensitive emulsion on the copper Board, placing negative photographic image on a copper Board to implement the exposure so that the image is formed on the copper Board.

Summary of the invention According to the first aspect of the present invention provides a method of forming patterns in the form of a diffraction grating or hologram producing a variable optical effect, on the substrate, and contains the following steps: a) providing an adhesive on a substrate, b) applying by deposition of metal powder on the adhesive; C) embossing patterns, producing a variable optical effect on the metal powder.

When the metallic powder is applied to a discontinuous way.

In addition, the adhesive is provided in the ionic picture when viewed through such a grating of lines and points.

In addition, points are halftone dots having diameters of less than 200 microns.

When this adhesive contains toner.

In addition, the step a) includes printing the adhesive using, for example, flexography and gravure printing.

When this metal is tin. The particle size of the metal powder is in the range of 0.1-100 μm. When the metallic powder is deposited on the adhesive.

In addition, step (b) further comprises removing excess metal powder, and the removal phase contains one or more of the processes of suction, gravity and vibration.

In addition, the metal powder may be a mixture of different metals. Different metals have different colors.

In addition, the metal powder and the adhesive or only one of these components further includes a magnetic or fluorescent environment.

In addition carry out the oxidation of the metal powder.

Moreover, the method further comprises the following step (b) stage crushing supported metal powder for forming the mirror polishing. At this stage of conditioning is carried out simultaneously with step (b).

Stage relief is additional contains the implementation of the additional embossing process after step (C), moreover, the level of embossing is more rough than used in step (b).

And further comprises step (g) providing a protective layer on top of embossed embossed powder.

When this protective layer contains an adhesive used in step (a). And the protective layer is printed on embossed embossed powder. When this protective layer is colored.

In addition, the substrate may be paper. And the finished substrate is a valuable document such as a banknote.

While these stages are carried out continuously on a substrate in the form of cloth, therefore, to provide patterns on the specified canvas with multiple variable effect.

According to the second aspect of the invention, the substrate carrier structure in the form of a diffraction grating or hologram producing a variable optical effect, boldly embossed into the metal powder.

This metal contains tin.

According to another aspect of the invention, the document is protected against counterfeiting, comprising a substrate according to the characteristics mentioned above. This document is a banknote. The authors have invented an entirely new method to provide structures, PSIA on the substrate. Preferably this adhesive with adhesion or the ability to create adhesiveness by heat or other treatment used with the appropriate weight to be linked to only one layer of metal powder. The adhesive allows you to firmly glue the subsequently applied metal powder to the substrate and precisely control the configuration of the application in contrast to the previous approaches. Also, the number of bound powder is correlated with the thickness of the adhesive. As will be explained below, it has special advantages in the case of valuable documents.

The invention also includes embossing patterns, producing a variable optical effect in the metal powder. The previous sentence was not concerned with the embossing of such structures, which require the formation of a very thin embossed elements. However, the invention results in a structure that can easily be used for the purposes of authentication and which is very difficult to copy.

In a typical case, the metal powder will be applied in a discontinuous form, for example, as a single layer of metal particles in the form of land or Islands. If he subsequently plumits, it appears that it is the City of the invention, in which the image is provided on a substrate, the method includes the following steps: a) providing an adhesive on the substrate in a configuration corresponding to the image; b) applying a metal powder to the adhesive.

In this aspect gains the advantage comes from the ability to manage the preparation of the adhesive for forming the image and then to reinforce this image by applying metal powder. This aspect of the invention has its own advantages regardless of whether or not embossed structure, producing a variable optical effect in a metal powder that is easy to evaluate. For example, this could lead to a new tactile long-term effect of deep print in bright powder of the same metal or complex powder, for example, the effects of tin/magnetized particles. In other words, not a microstructured, homogeneous (metal-like) properties. However, the following description will refer to the first aspect of the invention, although in most cases the marked points are equally applicable to the second aspect. Also, although the invention can be used with any type of optically variable effect, including oxides with changing the color of ologramma.

Preferably, the method further comprises the following step b) the step of conditioning applied metal powder for forming the mirror polishing. This phase of conditioning or polishing could be done separately or as part of the step of embossing a relief. However, mainly to carry out the two stages separately to extend the service life of a part or strip stamping of relief.

In the process, you can use any suitable metal powder, but where are the processes of conditioning, should be preferably selected powder, which is relatively soft, or able to be mitigated by processing, such as heating. Otherwise, the amount of force required for crushing, will destroy the structure of the substrate. Preferably, the material was also reasonably chemically inert so it can be easily manipulated, and that he resisted flexion, etc. It should not fade after application and must maintain gloss over the life of the product. Material that meets all these requirements, is tin. But could also use other materials such as indium, lead, cadmium and tal who is it has a low melting point and, thus, heating to temperatures below the melting point, for example 200oWith, leads to a substantial softening of the material. The method could be used with other metal powders, especially substances with fibrous or non-porous surfaces, or which do not require fine structure.

The tin powders are usually prepared using the processes of grinding, or using water or an inert gas, or by using ultrasound. Of these ultrasonic method produces a better quality product in terms of spherical particles, which has a significant impact on the flowing properties of the powder. Basically the range of sizes of the produced particles is from 1 μm to 100 μm depending on the process.

The first step in the process includes applying adhesive. The adhesive must be suitable for printing, it is preferable to form images with high resolution. Also important characteristics of drying: he must either long enough to be sticky so that the powder could be applied to it and stick to it (it can be, depending on the linear velocity, etc. ~ 1) or alternatively, he d is revane.

You can use curable under the action of ultraviolet radiation (UV) cationic resin. In this case, stamped parts are exposed to and acquire the stickiness before curing. This may allow binding of the powder, while curing is moving to completion, preferably with some heat.

The quantity of applied adhesive is also important. When there are too few may happen incomplete coverage. When there is too much adhesive will be held between the first layer of tin particles and bind additional layers, a result leading to unnecessary use of material.

From the viewpoint of adhesive strength would be better if the adhesive to some extent moistened side of the particles, for example, up to 1/2 of their radius. This not only ensures a good contact area, but also because then all of the applied force is always acting in shear mixture of fashion and fashion stretch, rather than in a pure fashion stretch (which is usually the weakest situation).

The thickness of the adhesive component of ~ 5 µm, is a reasonable compromise of these factors, although due to many factors affected it will be the an using traditional printing methods, such as flexography and gravure printing, but the preferred method, especially, which should be formed image is xerography, in which the adhesive contains toner. When using xerographic method it is possible to bind the powders of tin using a coating resin only 0.25 mg/cm2(and this includes the weight of the pigment). Good results can be obtained for many purposes, such as for checks, especially with good curing under the action of ultraviolet radiation (UV) of the upper layer as a protective coating.

Unlike deposits, formed in the traditional printing methods, microscopic examination of the sediments formed in xerographic processes, shows that the resin is in contact with a very small area of each particle and the resulting powders only freely supported and can be easily removed. When rolling they bind much more strongly acceptable and able to resist abrasion/bending etc., even before applying the top protective layer.

Preferred is a powder produced by ultrasound, although can be used other powders.

For applying metal powder is to use other methods type fluidized bed, etc., It may also be useful to produce vibration of the substrate during the application stage, to move particles on the surface in such a way as to ensure full coverage. Traditionally, the method will further comprise the step of removing any excess powder.

Technology, consisting in the application of the powder, and then removing excess material, already used in the technique of thermography and available commercial equipment capable of handling ~10000 sheets per hour. When using other methods carry out the burning of the powder, especially for dense metal powders.

Where excess powder must be removed, this operation must be performed efficiently. In one case this is done by suction. Then the excess powder is passed into a cyclone separator, which removes any fiber dust/paper, etc. that may have been sucked away with the tin, before returning the processed material through the system of sluicing in the hopper with powder for reuse.

You can improve the efficiency of the process of removing excess powder (if necessary), for example, through the use of a more powerful suction system, or through perevorachivaetsia vibration process.

The substrate can be selected from a wide variety of known materials, including rag paper, etc., and plastic materials such as polyethylene terephthalate (PET) Mylar thickness of 10 μm. Materials which have been used successfully include standard paper for the manufacture of banknotes, paper for making money with watermarks, barcodes, paper Astralux, other types of coated paper, standard paper for the photocopier, 80 g/m2silicone gasket paper and polyester film, oriented polypropylene (OPP) and other film materials, having a thickness in the range of 10-100 microns.

Metal powder such as tin, is able to deform in such a way as to smooth out the microscopic roughness of the paper surface, but is not able to deform sufficiently to eliminate irregularities in the thickness of the paper, which are commonly found in much larger scale (for example, ~1-2 mm). Such surface irregularities can be smoothed only by application of pressure from histopathology pair of rollers, with the aim of crushing of the microstructure of the paper, or by application of pressure to the underside of buwa it, probably it would be useful to use a paper with good thickness uniformity, although in fact you can use any paper (or hard surface).

It is also possible to use this method to provide a hologram on a plastic foil, and we have successfully provided on the foil with a thickness in the range of 10-100 microns.

If you use silicone gasket paper, after the formation of the hologram of the latter remains attached to the strip stamping relief and can be removed and transferred intact to another substrate type polyethylene terephthalate (PET) using adhesive. Thus, it is possible to develop an "offset" technique for applying holograms on the substrate that is sensitive to heat and pressure, for example, shrink-sleeve one-time use.

In preferred methods, as soon as the powder is attached to the surface of the paper, he should plumits so to transform it into a mirror, and should microrelief to jostle with a holographic image. This can be accomplished using a single operation or by using a two-step process with the initial formation of conditioning/mirrors, with the subsequent stage of the stamping surface, Etapa is possible to provide a protective layer over the embossed embossed powder. This protective layer prevents mechanical damage to the relief surface during use, and also helps to prevent from copying elements of protection against counterfeiting, by sealing boldly embossed profile. In this latter context, it is preferable if the protective layer is formed of the same material as the adhesive or at least with very similar material so that any attempt to remove the protective layer, would have destroyed the structure, producing a variable optical effect. It should be noted that a key advantage of this approach is that the structure forming the variable optical effect, is not contained on a continuous film of material, but it looks like a mosaic of microscopic plates. If the organic layer, which keeps them together is destroyed, they are just broken, and the hologram can not be more fixed. Therefore, if the composition of the adhesive/protective layer is carefully selected, these holograms should have the best protection against counterfeiting than metallic hologram obtained by the method of hot stamping or flame spraying.

Direct coupling of the protective layer to the adhesive/substrate through porites and may be introduced intentionally to any desirable degree.

To ensure the required mechanical properties of the material must be flexible and resistant to scratches, but also must be able to pass various chemical tests/test solvent resistance required by the industry.

High-quality playback of images with a variable optical effect is obtained by coating a continuous metal coating. However, you can get acceptable playback using a much lower load, for example 25-50% cover coated with tin, for example, in the form of lines or a grid of points. This provides the ability to combine metallic image with pre-printed color images. It also provides an opportunity to reduce costs by minimizing the use of materials.

It is relatively easy to achieve periodically spaced columns and rows (or points) of the metal powder, which, provided that they are accurately posted, invisible to the naked eye. If the image with lines at equal intervals on a transparent substrate to rotate over this image, the observed moire interference fringe. Perhaps the which will become visible only in the formation of interference fringes. Such effects would be very expensive to duplicate by other means, but to this method, they do not add significant additional value.

Through the application of the top coating of the metallized layers (transparent) color lucky you can get a wide range of colors, such as gold, etc.

You can change the color of metal powder by simple oxidation or chemical surface treatment of metallic particles. These colored powders can be used to obtain (mirror-polished metal deposits with a range of attractive colors from gold to iridescent purple that can easily be holographically embossed jostle.

Mixing powders (tin) different colors can be obtained variegated effects. Such effects can also be obtained by mixing the powder (tin) with other materials, for example polymers, powders, pigments, fibers, etc. Other objects, metal and non-metal, could be used in mixtures with tin, for example: - dyes - inorganic/organic pigments/ paints
- luminescence - fluorescent or phosphorescent prints
- magnetics - oxides, ores RAS are pressed into the surface to a depth of less than 1 μm. You can generate macrorelief embossed elements on metallic paper by pushing the pictures/images to a depth of ~0-5 microns.

Another advantage of the powder approach is as follows: deposits easily include magnetic media that may be encoded with information protection against counterfeiting. This could be achieved by mixing magnetic powders with tin or through their inclusion in the adhesive.

Can also be activated fluorescent material by mixing metallic and fluorescent powders and their joint application.

Cheap hand held device with eddy currents are used in many applications, such as measuring the thickness of the coating, or to differentiate between different metals. They work using a small coil to induce eddy currents in the object. The amplitude and the phase currents change the reactance of the coil, which can be easily measured.

From the electrical point of view of tin deposits differ markedly from the hot foil stamping or metallic inks. Therefore, to confirm the authenticity could develop a device based on measurements Vikhrev possibly all) other virtually any application print with protection against counterfeiting. In most cases, they do not require that the underlying process, we have added additional steps that have not resulted in a relatively large value of the costs of the production process.

The basic process can inflict on one or both sides of the paper hologram of any size. The latter can be done either through the use of the second passage, or perhaps through the use of single-pass system. Holograms do not need to be contiguous and could, for example, be located at various remote areas of the banknote, or could form a frame around the periphery. It would be very expensive to do it using foil hot stamping. The cost would be proportional to the total area covered with tin, and not a complete square, closed hologram (as in the case of hot forming).

An attractive feature of this technology is its ability to form a metallic image, which can be holographically embossed ottieni. Currently this can only be achieved with the use of expensive, multi-type methods demetallization. It is possible to form images using this technologist in particular, applicable to documents that are protected from counterfeiting, which include banknotes, cheques (whether cheques or cheques for purchases in stores), bonds, share certificates, licenses, some types of identity cards, smart card, passport, visa, savings accounts, vouchers, certificates, seals and labels disposable, labels, authentication, etc., Indeed, any security, protected from tampering, based on the plastic material, can be formed using this invention. Of course, where a flexible product, type of banknotes should be selected suitable plastic material such as polypropylene.

Brief description of drawings
The invention is further explained in the description of specific variants of its embodiment with reference to the accompanying drawings, in which:
Fig.1 depicts a schematic view of the device,
Fig.2A and 2B illustrate a paper coated with powder before and after crushing, in section, approximately 500-fold magnification,
Fig.3A and 3B depict a typical surface holograms of tin approximately 1000-fold magnification,
Fig.4 schematically illustrate rollers for crushing,
Fig.5 depicts a graph of the hardness B of the Sabbath. Fig. 7 illustrates the range nieletnich metallic images, showing the effect of conditioning/polishing with polished metal gasket
Fig. 8A-8B illustrate examples of the metallic image on the banknote,
Fig. 9A and 9B illustrate, respectively, six examples of the source of the photomasks, and the same six after plating and embossing relief with different densities of fat,
Fig.10 schematically illustrates macrorelief embossed product.

A detailed description of the preferred options of the incarnation
The device shown in Fig.1, contains node 1 print adhesive, through which is supplied the paper web 2. The adhesive is printed on the upper surface 3 of the blade 2 either continuously or in a configuration that defines the image type half-tone image. As mentioned above, this seal may use any known technique, such as flexography and gravure printing, or may contain a xerography. In the case of adhesive which is curable by ultraviolet radiation (UV) cationic system, the canvas can then be irradiated to initiate curing and develop stickiness. Then printed canvas 2 is held in the node 4 application m is OK is applied on the upper surface 3 of the canvas and will stick to the printed adhesive, which is supported in its adhesive state. Then canvas 2 oborachivaetsya around the guide roller 6 so that the excess metal powder that is not stuck to the cloth fell down in the recycle bin 7. This can be facilitated by a pump (not shown). Then the blade goes into the drying unit 8, which dries the adhesive, and then passes into a secondary node 9 removing excess metal powder, where the canvas vibrates, and suction is applied to remove any remaining excess metal powder. This process can be stopped, providing working paper roll, which can Kalankatuatsi and boldly to share later.

Otherwise, the fabric passes in the node 10 of conditioning, where the metal powder plumits, relying on the canvas 2, forming a mirror surface, which is then node 11 embossing relief, relief packs together with microstructure, which determines the structure, producing a variable optical effect. Finally, boldly embossed fabric passes in the final site 12 printing, in which a protective lacquer, which may be the adhesive that is applied at node 1, is applied over the embossed embossed metal powder. Then Polota eriny process includes execution of all sub-processes (i.e. printing of adhesive, UV irradiation (on request), application and removal of the metal calendering and embossing, and finally, surface lacquered) without interrupting the production process. Intermittent process involves the preparation of a working paper roll as described previously. The subsequent stages (that is, calendering, embossing and surface coating lacquer) are offline later.

Node 4 applying metal powder should be supplied with a continuous flow of powder which completely closes the covering area. There is not a perfect system powder-coating, and therefore must be applied over, to ensure that there are no bare areas.

To illustrate how a flow coating application of a continuous strip of powder thickness 2 mm, width of 1 m and with a line speed of 100 m/min, could mean applying 200 l of powder per minute (2 liters/min/cm).

It is clear that 2 mm powder - this is a large surplus when required coating thickness <0,1 mm If the sprayer is designed well, it should be possible to reduce the thickness of the coating to a much lower figures than this, which minimizes the amount of powder in circulation.

Generally speaking, the powder will not be ordinary is specialsa equipment Faust, which uses asymmetric Cam device for vibration of the hopper at a frequency of 25 Hz. The powder hopper has a full stroke1 mm After passing through the slot of the powder is held in a dispenser (not shown), which consists of a flat plate, inclined at an angle of 20-30oto the horizon, which drilled staggered holes at a distance of 2 mm and a diameter of 2 mm From the viewpoint of uniformity of application it is important that the flow rate and the position of the holes/the angle of the spray were such that the powder passed down plate, and not just passed through the first one or two rows of holes.

Tin falls on the paper, walking distance of 4-6 cm (depending on whether it falls in the upper part or the lower part of the plate atomizer). Since tin is a heavy material, the powder coming out of the holes of the spray tends to fall vertically, and the degree of fusion of adjacent streams is very limited. The vibration of the hopper with a frequency of 25 Hz, very little effect on the improvement of the uniformity of the coating. To ensure uniform coating, it is important that the sprayer was designed so that the powder passed down plate and went although the OK will accelerate and, thus, the height will determine the speed of the particles when they reach the adhesive. The higher the speed of the collision, the greater the initial penetration of the particles into the adhesive. Higher speed also can cause the powder to be compacted, and this may provide some enhanced coverage.

However, increasing the drop height may have a negative effect, consisting in the fact that the powder becomes more sensitive to the effects of selection and etc.

Using slotted 5 mm x 10 cm provided the flow rate tin ~12 kg/min, without reloading the dispenser. Assuming that the density of the powder is 40% of the density of solid material (i.e. 7.3 and 2.9 g/cm3respectively), the flow rate will be ~4.1 l/min At a linear velocity of 100 m/min, this would provide coverage only ~400 ám.

To increase the flow rates could be applied by various methods. The primary mechanism of control by the flow rate is cut, and a wide opening would lead to applying more powder. Can also help a stronger vibration. Both of these measures may require an increase in plate dispenser. As an alternative, you could take the device with many PKI depends on the spherical powder. The less there is of irregular-shaped particles, the higher the flow velocity can be achieved.

It is important to ensure that the powder remains free from contaminants such as oils or fats, because of relatively small amounts of such materials can have a noticeable effect on the flow rate, can be detrimental to adhesion and can cause contamination of the strip.

More than 90% of the powder deposited on the cloth, not directly used, and it must be collected and reused. During the process clearly foreign material should be removed. It is important that this material be removed, or when the precipitation will occur defects, and may damage the shims.

For this purpose, can be used a cyclone separator (not shown). It will very effectively remove the lighter material, but will not remove the heavier particles of dirt. In this case, it is important to erase both types. The combination of cyclone separation and filtration should be appropriate. For example, should be appropriate filtering to pass only particles of size <150 microns, but it will tend to slow down performance if the size to be located as close as possible to the unit application of the powder. This will minimize the difficulties of transporting powder tin back into a cyclone separator (as well as reducing the potential of spilling). Until used, the distance kept to a minimum, it should be possible to do so using only vacuum line suction, rather than to turn to more complex mechanical methods.

The table lists the set of adhesives that have been successfully used.

Fig. 2A and 2B illustrate coated metal powder substrate before and after crushing, respectively, while Fig.3A and 3B show the surface of a typical hologram of the tin. In Fig.2A shows the individual grains of the tin. Also, Fig.3A and 3B show plates, formed by convergence flattened and not fused spheres with a diameter of 30-50 μm.

To understand the effect of variables during the process of conditioning, was tested. It was found that at low pressures on the rollers for crushing transferred a significant amount of metal powder, whereas at high pressures it was not so. It turned out that the high pressure forced the tin to make the paper structure, and thus attained a high level mehanicheskaya surface is obtained for the smooth surface of the roller crushing, so only part of the surface of the tin remains attached to the paper. At lower applied pressures obtained less mechanical grip with the printing surface of the paper, and then get a more random distribution of parts of the surface. Using optimised adhesive systems should also minimize the transfer.

From the obtained results it was clear that the quality mirror polishing, obtained at the first stage, has a direct impact on the quality of the final hologram. Defects introduced in the first stage, only partially removed on the second, if you do not use very high pressure embossing relief.

The size distribution of the powder is also a factor that will affect the pressure required for the formation of the mirror. As mentioned previously, when you used the powders finer grinding, then to obtain the mirrors of comparable quality required higher pressure.

Another variable that affects the pressure required to form the mirror hologram (holographic embossed micro-relief) is the diameter of the rollers, as it affects the width of the capture area (crushing), which is the region is about and after crushing, and the size of the rollers, it is possible to calculate the area of conditioning, which is essentially the length of the arc a - b in Fig.4, taken at L times the width of the instance:
L=(R(ho-hf)-(ho-hf)2/4)1/2,
where R is the radius of the roller, a hohf- initial and final thickness of the sheet.

In this particular case, the angle clutchin fact very small, and the radial pressure is applied almost directly from above. In turn, this leads to the spread of the particles in the parties equally in all directions, until they face material, extending in the other direction, rather than solely in the direction of rotation.

At low pressures, the formation of the mirror occurs only in thick sections of the sheet. Powder tin, which was printed on thin sections of leaf, in fact, was not affected. At higher pressures, tin/paper in thick sections progressively plushies up until their combined thickness does not become equal to the thickness of the thinner parts of the leaf, where they also began to plumits so as to form a mirror surface. Thus, the uniformity of thickness of paper is the key To a hologram of pure tin foil required a significantly lower pressure (e.g. ~25%), than covered with powder paper. The above observations suggest that the main obstacle that must be overcome, and which necessitates the use of high pressure rollers, consists in smoothing the paper in such a way as to destroy the irregularities in the thickness of the preferable means of powder.

Preliminary rolling for performing mirror polishing significantly reduces the amount of pressure required to form the finished hologram. Instead, there is a sequence of events similar to that which took place before with thick sections, forming a first hologram at low pressures, while the more delicate areas for successful embossing demanded pressure is typically ~0.5 t/linear inch (~ 0.2 tons/linear cm). It is therefore evident that the compression achieved during the pre-rolling was done through a flexible process, and when the pressure was removed, uneven thickness was coming back (at least partially).

A possible way to combat this effect and reduce the required pressure may be lined with rubber counter-roller, which will deform to nastri what about all the irregularities of the thickness, trapped surface roughness on the underside.

The service life of the gasket is a key parameter in assessing the full costs of the process. There are a number of wear mechanisms that have been identified, and the exact nature of the mechanisms that govern the life of the strip, is probably a complex function of all of them. Replacement for another material to change this mechanism. Unfortunately, given the complexity of the situation, it is difficult to predict to what extent the life of the pads could be obtained from simple theoretical considerations.

To assess the extent of the problem is the rapid wear of the pads, they were attached to the upper platen, and a closed loop of fabric covered with tin paper was attached to the lower platen. After certain intervals of the rolling test strip was passed through the system to register as a holographic image.

When using non-reinforced pads or rollers for embossing relief at room temperature, it was clear that the quality of the holograms has become noticeably worse only after ~100 operations. However, it was not because of wear on the surface, but rather due to the stretching of the strip when multiple procyclicality edge effects. The use of hardened strip solves this problem without visible signs of wear or stretching after ~1000 operations. Hardened pads are used, for example, embossing foil credit card at high pressure. If necessary, can be used for additional reinforcement, such as narisovanie.

There are various ways to minimize this effect. First, in these experiments we used the maximum working pressure sufficient for simultaneous and mirror polishing and embossing the surface. The formation of mirror polishing/embossing at a lower pressure on the rubber counter roller should also allow a significant decrease in the pressure rolling.

Fig.5 depicts a graph of Brinell hardness for tin depending on the temperature, which was obtained by measuring the size of the indentation formed by the application of standard strength.

Below is a dependency that is used for communication of Brinell hardness with indentation size:
The number of Brinell hardness = P/(D/2(D(D2-d2)1/2),
where P = load (kg), D = ball diameter (mm), d = di is, required to achieve the indentation of a given size, four times. Rolling at elevated temperatures also would have the effect of significantly reducing the mechanical action of hardening, especially if the tin can be brought to temperatures exceeding 100oC. Therefore, it would be possible to apply a lower pressure, and this, together with the fact that the material is much softer, should improve the life of the strip.

To evaluate the effect of temperature on the mirror polishing/embossing, test strips were run at 200oWith the same pressure range, which was used at room temperature.

Happened a very similar sequence of events. At low pressures, the tin was plushies only in thick sections of the sheet. Increasing the pressure increased the proportion of the surface that was smooth. In General, the quality of the reflecting layer was better each time used the pressure was reduced limit of the desired pressure.

It should be noted that in this experimental setup, the paper is not pre-heated. Heat was supplied to the tin through the paper. Given that the paper was in contact with the heated platen only pricheski, ought to heat the holographic platen and maybe a roller for crushing, if used. It would be convenient to use heat for drying the adhesive, and this would effectively act as preheating before the formation of the mirror. Heating could be achieved, for example, by infrared radiation or convection.

After the final operation rolling deposits consist of layers of tin with an average thickness of ~ 30 µm. Metallized areas usually 0-10 μm thicker than the original paper, and perhaps ~20 μm thicker than the laminated sections of the paper that were not metallized. (Tin tends to fill the pores/roughness in the paper, and thus the final thickness is always less than the sum of the thickness of the tin and paper).

This is preferably compared to gravure printing, which can cause thickening of paper banknotes, for example, 50 μm.

If the extension of the thickness of the paper causes problems, such as causing difficulties due to non-uniform packing, there are a variety of possible tools that could be tested. Holograms could be centered on both ends, or along the periphery of the banknote. Unlike foil goraco full square metallization.

Alternatively, the hologram could be positioned so that during the rolling pressure was applied only to metalized areas. Thus, the thickness of the hologram could be designed so that it was actually the same as the adjacent neprochitannaya paper.

At last the final stage, the top protective coating 30 is provided on the tin particles 31, which is already stuck to the substrate 2 via the adhesive 32 (Fig.6).

The main purpose of the upper cover 30 is to prevent mechanical damage to boldly embossed surface during use, and to prevent copying of elements of protection against forgery.

In the latter context, preferably, when the adhesive 32 and the top layer 30 are the same or at least very similar materials so that any attempt to remove the top layer would destroy the hologram. It should be noted that a key advantage of this approach is that the hologram is not contained on a continuous film of material, but it looks like a mosaic of microscopic plates, Fig.6.

To study the characteristics of the image resolution that can be obtained by this method was podvorachivalsya resin, attached to the paper, re-melted and contacted with a powder of tin, and then powder tin was plumilla/polished. Fig.7 and 8 depict examples of the obtained results. Did images of very satisfactory quality. The two bottom sample in Fig.8 were clearly disney with holograms, while the upper sample was metallized and not Tannen relief. In the final product of the hologram could be designed to complement each of the images.

Halftone originals gave the best results, because the quality of their play during the photocopier was better. A similar approach has also been successfully demonstrated by re-flow of the resin in the images obtained by laser printing, as well as some prints intaglio printing.

Inevitably in this process will be some loss of resolution. For example, if you have marked the point of the adhesive 20 μm and patch the tin particle size 40 μm, the particle will be like to hover at the edges of any metallized area. It is possible that a very thin metal image can be achieved by using the zoom point, such as POS/p> Then the particles plumata and spread further. For particles with a dense packing it can make a relatively modest increase of ~10% in the area before they touch each other and form a many-sided plates. Particles at the edges of the metallized areas are not supported on all sides and have the opportunity to increase the area up to greater extent. Studies of these particles suggests that under normal conditions, they can increase in area by ~50%. This, together with the effect of the overhang limits the resolution of the method is approximately 100 μm. It may be possible to slightly improve this figure, using a powder with particles of low size, but as discussed earlier, should be avoided particle size less than 25 microns, and this determines the absolute maximum achievable resolution.

The net effect of this is relatively small loss of resolution and overall darkening of the image, because each of the halftone dot increases in size. This last effect could be compensated by intentionally creating more light in the original image.

However, the spreading effect can usefully be applied in reduction of colicin be applied in the form of a matrix of pixels, preferable in the form of a continuous layer. Then during the crushing tin spreads to fill the gaps. The small size of the points maximizes the fraction of particles of tin on marginal areas and, consequently, the degree of spreading effect. Fig. 9 depicts deposits with progressive decreasing of the metal coating. You may notice that a small loss of image resolution is due to the actions of the original created holographic effect.

Tests showed that using a very thin matrix of dots (diameter ~200 µm) actually completes the coverage that could be obtained with the original coating of adhesive is ~60%. Very acceptable results were obtained using a 50% dot coverage. At 40% it was visible to the naked eye that full coverage was not achieved, although holographic detail is still quite clear.

Perhaps the most important factor that controls the resolution is the application of the adhesive. It is clear that the resolution of the resulting images will not be better than the resolution of the printed image. The quantity of the applied adhesive is also important: if it is too low, it may be incomplete coverage. If it's too much, then the capacity process (not shown in Fig.1), which boldly embossed metal powder is additionally subjected microtelephone stamping. Thus, as seen in Fig.10, the layer 21 exposed tin microtelephone the stamping with holographic elements, shown by item number 22 and optionally subjected microtelephone stamping, as shown by the position number 23. For example, when rolling on cloth, you can transfer its surface morphology on the layer of tin so that it looks like the metallized fabric. This could be important for protection of trademarks for goods and high quality fabrics.

In many cases, you can perform macrorelief stamping, without destroying existing holographic elements. The best results are probably obtained when macrorelief image consists of high/low/inclined flat parts, such as line charts, Fresnel lens etc


Claims

1. The method of forming patterns in the form of a diffraction grating or hologram producing a variable optical effect, on the substrate, containing the following steps: a) providing an adhesive on a substrate, b) applying by deposition of metal powder on the adhesive 2. The method according to p. 1, characterized in that the metal powder is applied to a discontinuous way.

3. The method according to p. 1, characterized in that the adhesive is provided in the form of a grid of lines or points.

4. The method according to p. 3, characterized in that the lines or dots are arranged so that they form a moire interference pattern when viewed through such a grating of lines and points.

5. The method according to p. 3, characterized in that the points are halftone dots.

6. The method according to p. 5, characterized in that the dots have diameters of less than 200 microns.

7. The method according to any of the preceding paragraphs, wherein the adhesive contains toner.

8. The method according to any of paragraphs.1-6, characterized in that step a) includes printing the adhesive using, for example, flexography and gravure printing.

9. The method according to any of the preceding items, wherein the metal is tin.

10. The method according to any of the preceding paragraphs, characterized in that the particle size of the metal powder is in the range of 0.1-100 μm.

11. The method according to any of the preceding paragraphs, characterized in that the metal powder is deposited on the adhesive.

12. The method according to any of the preceding paragraphs, featuring the notable the removal phase contains one or more of the processes of suction, gravity and vibration.

14. The method according to any of the preceding paragraphs, characterized in that the metal powder is a mixture of different metals.

15. The method according to p. 14, characterized in that different metals have different colors.

16. The method according to any of the preceding paragraphs, characterized in that it further includes a magnetic or fluorescent environment in a metal powder and an adhesive or only one of these components.

17. The method according to any of the preceding paragraphs, characterized in that it further carry out the oxidation of the metal powder.

18. The method according to any of the preceding paragraphs, characterized in that it further comprises the following step (b) stage crushing supported metal powder for forming the mirror polishing.

19. The method according to p. 18, wherein the step of conditioning is carried out simultaneously with step (b).

20. The method according to any of the preceding paragraphs, characterized in that the stage embossing is carried out using heated parts embossing.

21. The method according to any of the preceding paragraphs, the steps (C), moreover, the level of embossing is more rough than used in step (b).

22. The method according to any of the preceding paragraphs, characterized in that it further comprises step (g) providing a protective layer on top of embossed embossed powder.

23. The method according to p. 22, characterized in that the protective layer contains an adhesive used in step (a).

24. The method according to p. 22 or 23, characterized in that the protective layer is printed on embossed embossed powder.

25. The method according to any of paragraphs.22-24, characterized in that the protective layer is colored.

26. The method according to any of the preceding items, wherein the substrate is paper.

27. The method according to any of the preceding paragraphs, characterized in that the finished substrate is a valuable document such as a banknote.

28. The method according to any of the preceding paragraphs, characterized in that the steps carried out continuously on a substrate in the form of cloth thus to provide patterns on the specified canvas with multiple variable effect.

29. The substrate carrier structure in the form of a diffraction grating or hologram producing a variable optical effect, boldly embossed in metallicheskaya polozka under item 29 or 30.

32. The document under item 31, wherein the document is a banknote.

 

Same patents:

The invention relates to a protective drawings for securities, to the printing of this pattern and securities with a protective figure

The invention relates to printing and can be used in the production of securities, as well as other counterfeit printed products
The invention relates to printing production and can be used in the manufacture of valuable documents that require increased protection against counterfeiting, in particular in the manufacture of forms of documents used in Railways, such as train travel documents, transportation documents on baggage, cargo, mail or miscellaneous charges

The invention relates to a protective element for securities intended for manufacturing banknotes and the like securities

The way iris print // 2188764
The invention relates to the field of printing and in particular to printing remedies documents

The invention relates to the manufacture of counterfeit paper by melting when heated film bearing a printed image protection

The invention relates to the field of protection of securities, receipts and other documents and can be used in the production of banknotes, bonds, checks, tickets, cards, documents and other securities with a high degree of protection against forgery

FIELD: information medium sealed up by the method of metallographic printing, method for its manufacture, as well as a printing plate suitable for the purpose and the method for its manufacture.

SUBSTANCE: the information medium, first of all a bank note, securities or a similar document, which has at least one sealed up section (13) and at least one separate section (14) practically completely encircled by this section. The mentioned section (13) and the separate section (14) are sealed up by the metallographic method, and both sections are sealed up by paint coats of a different thickness and differ from one another.

EFFECT: provided a high degree of protection against forgery of the information medium.

21 cl, 11 dwg

FIELD: important documents with protective attributes, combination of matters with two automatically controlled properties for protecting important documents against counterfeit, methods for making such documents and methods for testing authenticity of charred matters and ash.

SUBSTANCE: important document, mainly bank note or person certificate is characterized by use at least of two luminophors whose luminescent properties may be automatically and individually monitored. First luminophore irreversibly losses its luminescent properties at first temperature. Second luminophore irreversibly losses its luminescent properties at second temperature. First and (or) second temperature exceeds natural temperature of burning important document. It allows to identify document according to itself and also according to its ash and prevents possibility of illegal regeneration of materials designed for protecting against counterfeit in order to make duplicates of documents.

EFFECT: enhanced reliability of identifying important documents.

29 cl

FIELD: manufacture of securities.

SUBSTANCE: metallographic printing form has printing members disposed on working surface and made in the form of deepened strokes having cross section profile of asymmetric shape with various angles of inclination of side faces.

EFFECT: increased extent of protection of securities from counterfeit.

17 cl, 4 dwg

FIELD: manufacture of securities.

SUBSTANCE: method involves providing pattern comprising combination of ink layer protrusions and slots therebetween, with width of ink layer protrusions making at least 0.5 mm.

EFFECT: increased extent of protection of securities from counterfeit.

17 cl, 4 dwg

FIELD: manufacture of securities.

SUBSTANCE: method involves providing protrusions of equal width at their base portion and of various cross section at apexes within the range of length of each protrusion.

EFFECT: increased extent of protection of securities from counterfeit.

17 cl, 4 dwg

FIELD: data carriers.

SUBSTANCE: data carrier 14 with forgery-protecting imprint 1 made by metallographic printing method consists of several contrasting structural elements 2,3,4,5,7,22, positioned with precise alignment to each other, while one portion of these structural elements 3,4,5,7 is made relief-type and can be sensed by touch, and other portion of structural element 2, 22 is made flat and undetectable by touch.

EFFECT: exceptionally high level of protection.

4 cl, 9 dwg

FIELD: printing.

SUBSTANCE: method includes use of freely mounted relatively to shape cylinder rolling cylinder, for rolling portions of composite printing form of shape cylinder, rolling cylinders being made with possible forming of portions of stripes of multicolored paints on shape cylinder.

EFFECT: higher efficiency.

3 cl, 9 dwg

FIELD: image printing technologies.

SUBSTANCE: required color is produced by mixing colors of image points, and on substrate fluorescent point of printing paints image are formed, which contain pigments fluorescent when excited by a certain electromagnetic emission, and also non-fluorescent image points of printing paints, containing colored pigments, non-fluorescent when excited by a certain electromagnetic emission. Aforementioned fluorescent image points and non-fluorescent image points are positioned on substrate in staggered order relatively to each other.

EFFECT: higher efficiency, higher quality.

2 cl, 4 ex

FIELD: data carriers.

SUBSTANCE: data carrier is provided with protective element, which allows at least visual control and has at least on a portion an engraving, which is a semi-tone blind engraving, produced by metallographic printing without ink feed, and also disclosed are method for making a data carrier and printing form for making protective element by means of blind engraving.

EFFECT: higher level of protection from forgery.

3 cl, 13 dwg

FIELD: methods of producing data carriers.

SUBSTANCE: method can be used for making persona; identifications in form of cards, securities etc. Method of making info carrier (1,10) provided with protective element having optically variable properties. The element has at least one distinguish marking (5, 6, 11) and at least one light-permeable layer (4) with optically variable properties. Layer having optically variable properties is at least at several parts overlapped with marking. Light-permeable layer (4) with optically variable properties is applied onto data carrier and marking (5, 6, and 11) is made through the layer onto data carrier (7) formed by means of laser radiation. Layer (4) with optically transparent properties has material, which creates optical variable effect. Moreover, the layer stays invariable under influence of laser radiation. Method provides high protection against imitation.

EFFECT: simplification; reduced cost of production.

30 cl, 4 dwg

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