EP2401936A2 - Jewellery stone with protective coating - Google Patents

Abstract

The method involves holding a gemstone (1) via a holding device, and providing a mirror layer (4) on the gemstone. A material forms a protective layer (6) or lacquer layer and is partially applied on the mirror layer. The material is applied in form of lacquer drops (5) on the gemstone in a same direction. The gemstone is radiated from outlet openings of a press head (12). The material is hardened by application of an UV-radiation or by joining of reactive components. A geometry of the gemstone is detected by a scanning device. An independent claim is also included for a gemstone that comprises a front side.

Description

The invention relates to a method for coating at least one, in particular faceted ground, gemstone with a protective layer, wherein the gemstone is held by a holding device and is at least partially provided with a mirror layer and wherein the protective layer forming material in liquid form at least partially on the mirror layer is applied and then cured.

Gemstones are for jewelry and often for the decoration of everyday objects such. B. garments used and arranged for these purposes in or on a substrate. Those regions of the gemstone which are arranged in or on the carrier material are often provided with a mirror layer, for example by silvering, by physical vapor deposition (PVD) or by a wet-chemical method.

In order to protect this mirror layer from wear, corrosion and the like, it is often provided, in particular on the provided with the mirror layer regions of the gemstone to apply a protective layer, whereby the gem is additionally refined. Such a protective layer may be a lacquer layer. If only those areas which are provided with a mirror layer are painted, it is necessary to cover the remaining areas of the gemstone in order to prevent these areas from coming into contact with the paint which forms the protective layer for the mirror layer. In addition, the gemstones must be held during painting by a holding device. For this purpose, it may be provided to embed the areas not provided with a mirror layer in a thermoplastic material, for example by sinking the gemstones in a wax plate. Subsequently, with a Lackierspraydose from whose nozzle the paint exits in the form of a spray with a large opening angle, the gemstone without consideration of not provided with the mirror layer areas are painted, and the holding device is mitlackiert, whereby the individual gems connected by a continuous lacquer layer are, if several, arranged in a holding device gemstones are painted.

This method has the disadvantage that when removing the gems from the mitlackierten holding device of which the gems were kept during painting and with which the not provided with a mirror layer areas of the gems were protected during painting, the gems from the hardened or at least dried on, continuous paint layer must be broken, causing this lacquer layer is locally injured on the gemstones. The completion of the lacquer layer at the edges of the respective gemstones is not determinable, since the place of "breakage" of the lacquer layer is not predeterminable and controllable. A similar problem also arises when painting large parts, where the areas to be coated are taped with adhesive tape and removed after drying the paint layer again. In contrast to large-area parts, such. Body parts, these damages are more serious by the break of the paint layer but smaller gemstones with diameters of less than 1 mm and it can also lead to damage of the gem itself.

Such locations form a point of attack for further detachment points for the protective layer formed in the form of a lacquer layer. In particular, small gems are particularly sensitive at their edges. Since the break of the lacquer layer when removing the gems from the fixture is not always in the same place of the gem, it can also happen that the lacquer layer is partially deducted from the gemstone before it breaks. The mirror layer, which is often only a few microns thick, even exposed or even removed. It is also possible that the gem is damaged in itself.

Such exposed from the paint layer locations are preferred starting points for corrosion, since only the thin mirror layer must be crawled or corroded, which ultimately the mirror layer or the gemstone is destroyed.

Due to the forcibly necessary breaking out of the gems from the holding device also results in a restriction on the material to be used of the protective layer. So far, only brittle paints are used for previously used in the prior art painting, since they can break relatively easily. For other paints, the removal of gemstones from the Holding device even greater damage than the above-mentioned damage.

The object of the invention is to avoid the above drawbacks and to provide a method for applying a protective layer, in particular a lacquer layer, to an at least partially provided with a mirror layer gemstone available, but still technically easy and fast abzufatten without damaging the Lead Gemstone.

This is achieved by a method having the features of claim 1.

The gem to be provided with a protective layer is held by a holding device for the inventive method, wherein in the event that only portions of the gemstone are to be provided with a protective layer, the areas to be excluded from the protective layer, arranged in the holding device and / or may be covered. The protective layer forming material is applied in liquid form on the gemstone and then hardens.

The holding device can be, for example, a transfer film onto which the gemstones are glued, a thermoplastic support with a recess for the gemstone, a sieve device onto which the gemstone is sieved, or the like. It is also possible that the holding device is or has a support plate on which the gemstone or stones are placed, for example, with their panel, without providing separate fastening means.

According to the invention, it is now provided that the material forming the protective layer is applied in the form of a jet to the regions of the gemstone to be provided with a protective layer, in particular a lacquer layer, the drops applied to the gemstone being directed in substantially the same direction onto the Gemstone be applied, that is, the various drops have during application velocity vectors with substantially the same direction.

In this case, the material forming the protective layer is applied in liquid form to the desired areas on the outside of the gem, wherein the gem is at least partially provided with a mirror layer on which at least partially the protective layer is applied. It is provided that the protective layer is arranged on the back of the mirror layer. Namely, the mirror layer can serve to enhance the visual impression of a gemstone made of glass by reflecting rays of light on the backside of the gemstone and thereby imitating the fire of a diamond. If you look towards the front of the gemstone, you will feel it on the mirror layer, which is located on the back of the gem, reflected light as particularly sparkling. The back of the mirror layer is thus the side facing away from the gemstone side of the mirror layer. The gemstone facing side of the mirror layer is anyway formed mirrored. On the back of the mirror layer, the protective layer forming material is applied.

Due to the drop-shaped application with the protective layer material present in liquid form, the regions to be provided with the protective layer can be provided extremely precisely and precisely with the liquid material of the protective layer due to the substantially same directions of movement of the drops, and it is avoided Material of the protective layer must be applied over a large area on the gemstone after spraying with a spray. In a spray small droplets of the material of the protective layer are moved passively in the air stream, whereby the holder of the gems is mitgelackiert, which brings the aforementioned problems in removing the gems from the holding device with it. In addition, satellite drops form at the edges of the spray, which due to turbulence of the spray, perform complex and sometimes chaotic movements and have completely indefinable components of movement. These satellite drops encounter undesirable spots on the gemstone and may additionally cause the protective layer on the gemstone to bond to the jig, and this joint must be broken apart to remove the gemstone and cause the problems mentioned above.

It is provided that for the protection of the gemstone or the mirror layer, the protective layer is at least partially disposed on the mirror layer, whereby a mirror back coating is produced. In this case, the mirror layer has already been arranged on areas of the surface of the gemstone before the method according to the invention for the arrangement of a protective layer. For the mirror layer and its production method, conventional mirror layers or processes known in the state of the art come into question in the prior art, such as, for example, silvering by means of vapor deposition or in a conventional, wet-chemical manner.

In this case, in addition to a mirror layer further functional layers can be provided, which can also be protected by the protective layer according to the invention. These may be partially absorbing layers between the mirror layer and the surface of the base material of the gemstone and / or several, sometimes different layers, such as a decorative and a marking layers. Also, one or more adhesion promoting layers, between the functional layers and / or as the uppermost functional layer to which the protective layer is then applied, are conceivable. The mirror layer itself may be applied to the gemstone with varying reflectivity in the visible range, if desired. The functional layers may have roughened areas which facilitate subsequent setting and / or bonding of the gemstones in or on support materials. The applied decorative layers can represent a color layer which, for example, shows a logo and serves for the recognition of the gemstone and is arranged on areas below or above, ie on the outer surface of the mirror layer. In this case, the protective layer arranged on decorative and identification layers serves to protect these decorative and identification layers.

In general, these other different layers can also be applied to the gemstone using the method according to the invention for applying the protective layer.

The protective layer itself may be substantially transparent to light of the visible spectrum. But it can also be provided, the protective layer colored and / or provided with motifs or markings, in particular to fulfill decorative purposes.

Since the mirror layer on the gem often ends in the vicinity of the edge of the gem, an application of the protective layer forming material in these edge regions with the inventive method is of particular relevance. The edge of the gem may be the Rondiste or around the edge of the largest cross-sectional area of the gem, from which the gemstone tapers to a front and / or a back. The mirror layer is often arranged on the back of the gem. Since the mirror layer usually ends before the edge, the edge itself does not necessarily have to be provided with a protective layer.

As a result of the drop-shaped application of the gemstones according to the invention with the liquid protective layer material, the protective layer is selectively applied to the corresponding regions of the gemstones and the holding device is not necessarily co-coated. In particular, there are no continuous common protective layer areas on the holding device and the gemstone, from which the gemstone must be broken when removing the holding device. For this purpose, the invention provides that the drops of the beam of the liquid protective layer material have a velocity vector with substantially the same direction, so that the beam can be targeted to small areas of the gem. In contrast, the droplets in the spray of a spray can have no defined velocity vector, but are driven more or less chaotically by the suction of the spray.

The drops may form a jet of liquid protective layer material, which may consist of partially coherent and non-contiguous drops which impinge on the gem in a temporal sequence.

The method according to the invention is advantageous in particular for facetted cut gemstones since in particular the spray due to the undirected movement of the droplets according to a method of the prior art forms the material forming the protective layer to the facets of those regions of the gemstone can reach, which should not be provided with the protective layer. However, this is undesirable, inter alia, for aesthetic reasons. With the method according to the invention, a better edge coverage with the protective layer is possible by the selective, targeted irradiation.

Especially for industrial production, it may be provided not only to coat a gemstone with the method according to the invention with a protective layer, but to coat a plurality of gemstones as possible simultaneously, for which purpose the holding device has a plurality of holders for the individual gemstones.

Further advantageous embodiments of the invention are defined in the dependent claims.

As mentioned, the edge of the mirror layer is particularly affected by the above-mentioned problem and endangered when breaking out of the coated gems at least partially entrained.

For this reason, it is provided in one embodiment of the invention, the material forming the protective layer at least partially applied to the edge of the mirror layer, so that the edge of the mirror layer is covered or covered by the cured protective layer. Preferably, the edge of the mirror layer is covered or covered not only in sections, but along its entire circumference with the protective layer.

Instead of applying the material forming the protective layer to the edge of the mirror layer, it may also be provided in another embodiment to arrange the material forming the protective layer in the interior of the surface of the mirror layer so that areas of the edge of the mirror layer are omitted during the application and not be covered with the protective coating material. Subsequently, the dropped portions of the edge of the mirror layer that are not covered by the protective layer material are removed. For this purpose, an etching process may be provided, which indeed removes the mirror layer from the gemstone at the appropriate places, but does not or only slightly adversely affects the gemstone itself. The omitted areas of the border become so removes the protective layer covering or covering the newly formed edge of the mirror layer.

It can also be provided to produce a new edge of the mirror layer by removing areas of the mirror layer that are already covered with protective layer material. Again, however, it is provided that the newly formed edge of the mirror layer is covered or covered by the protective layer. For the removal, in particular the mirror layer, known methods are used in the prior art.

Such a targeted application of the protective layer forming material is possible due to the application by the drops with substantially the same direction vector.

In order to achieve an even better covering of the edge of the mirror layer, it can be provided that at least one second protective layer arranged on a protective layer, for example in the form of a further lacquer layer, is applied to areas of the gemstone by the method according to the invention. It may be provided that the first protective layer is intermediately cured before the liquid protective layer material for the second protective layer is applied in liquid form.

In a preferred embodiment of the invention, the gemstone is held in or on a surface of the holding device during the application of the protective layer. According to the invention, it can now be provided to apply the drops at least locally, essentially in the vertical direction, onto the holding device on the gemstone. If, for example, the holding device has recesses for one or more gemstones during the coating process, this means that the drops are applied at least locally in the region of the gemstones in the vertical direction to the imaginary outer end of the recesses in which the gemstones are held. If the holding device has a flat surface on which the gems are held, that is, for example, designed as a transfer film, as a sieve plate or other support plate is provided, the drops in this embodiment of the invention in with respect to this flat surface perpendicular direction to apply the or the gemstones.

If the gemstone has a board on its front side, while the rear side possibly provided with a mirror layer has a point, the gemstone can be arranged with its board in a recess of the holding device or on a flat carrier surface of the holding device and the drops of the material forming the protective layer be applied in the vertical direction on the board of the gem in the state held by the holding device. If the gemstones have a rondist which separates a front side of the gemstone from a back side, it may be provided to apply the droplets of the material forming the protective layer in a perpendicular direction to the imaginary surface through the rondelay of the gemstone in the state held by the holding device. Here, a rondiste the edge of the largest diameter of a gemstone understood, this edge as edge or edge surface, such as cylindrical, may be formed. By such methods, a uniform application with the protective layer forming material is possible and it is avoided that impinge on areas of the front, which should not be provided with a protective layer, obliquely moving drops, such as in a spray on these areas.

In a further embodiment of the invention, it is provided that the material forming the protective layer is applied not only to regions, for example, of the edge or the entire edge of the mirror layer, but to the entire mirror layer of the gemstone. In the case of a gem, the back of which is at least partially provided with a mirror layer, the back side of the device from which the drops are applied, and the edge of which is given by the rim, it may be provided that the entire back with the protective layer in the manner according to the invention is coated. In contrast, the front side facing the holding device can be essentially free of wearing material. After completion of the gem this is viewed through the front. The rear side opposite the front side is at least partially provided with a mirror layer whose mirrored surface on which the light beams are reflected, the Facing gemstone. On the side facing away from the mirror layer, the protective layer has been applied according to the invention.

In a preferred embodiment of the invention, the material forming the protective layer is selectively applied in the form of drops to areas of the gemstone. By a selective application, for example by selective irradiation, a particularly targeted application of the gems is possible omitting the holding device. The selective application means that the drops of the protective layer material are directed to specific areas of the gem. The omitted areas do not need to be covered because of the targeted application or placed in the fixture.

In general, however, it is also conceivable that the drops of the protective layer material are applied in the form of a uniform shower on the gemstone, wherein the drops have substantially the same direction. As a result, the holding device and the gemstone can be aligned such that no drops impinge simultaneously on edge regions of the gemstone and the holding device, so that a continuous layer on the holding device and the gemstone is avoided and the gemstone for removal from the holding device not from such a coherent layer has to be broken out.

In a particularly preferred embodiment of the invention it is provided that the gemstone is irradiated with the protective layer forming material from an outlet opening of a nozzle of a print head. Such printheads are well known in the art and are used in conventional inkjet printers for office or industrial use, so-called "industrial inkjet printers," for printing on paper or fabrics. The printhead can have a plurality of individually controllable nozzles, each of which has an outlet opening from which the material forming the protective layer exits. In particular, if a plurality of gemstones to be provided simultaneously with a protective layer, it can be provided to carry out the inventive method with a device that not only a Printhead but a whole series of, possibly parallel controlled printheads includes.

In contrast to methods in which the protective layer-forming material is sprayed on and the spray has an opening angle of up to 90 ° and more, the protective layer forming material from the outlet openings of the nozzles of a printhead occurs very precisely with a small opening angle and can also For example, be deflected by deflecting electrodes to desired locations of the gem.

In a particularly preferred embodiment of the invention, the material of the protective layer consists of a lacquer or the material of the protective layer comprises a lacquer. For this purpose, conventional, known in the art per se paints for gemstones are used. In particular, they may be commercially available paints which can be cured by exposure to radiation, e.g. so-called UV curable coatings.

In particular, for visible light, transparent protective layers or transparent lacquer layers, e.g. a so-called glass ink, as protective layers, provided for the inventive method. Nevertheless, lacquer layers of colored or at least pigmented lacquers or protective layers can also be used.

The material of the protective layer emerges from the outlet openings of the nozzle in the form of drops, the emerging drops moving in substantially the same direction at a similar speed and thus having a similar momentum, if the mass of the drops is likewise similar. The nozzle can be designed such that the drops are selectively directed to areas of the gem. The jet may consist of non-contiguous drops or comprise non-contiguous drops. In this case, the individual drops of the protective layer are applied with a similar impulse to the designated areas of the gem. It can be provided that the distance between the outlet opening for the droplets of the protective layer and the areas of the gemstone to be provided with the protective layer is kept as low as possible. In one embodiment of the invention this distance has a size of less than 5 cm, preferably less than 2 cm, preferably even less than 1 cm.

The inventive method is particularly well suited for smaller gems, which are also particularly sensitive to damage due to the aforementioned breaking out of a continuous protective layer on the gemstones and the holding device. In particular, gemstones with a diameter between 0.5 and 25 mm, preferably between 0.5 and 10 mm can be coated with a method according to the invention with a protective layer.

In one embodiment of the invention, the protective layer forming material is applied by a continuous inkjet method. This method is also known as a high pressure method in which the drops emerging from the nozzles of a printhead have a high flying speed. This prevents the formation of a spray and realizes a short coating time.

In a further embodiment of the invention, the material forming the protective layer is applied to areas of the gem with a drop-on-demand method. Such drop-on-demand methods include the piezo-inkjet process in which the droplets of the material of the protective layer are generated by piezoelectric actuators, the bubblejet process in which the droplets of the protective layer material are produced by thermal actuators or valve-controlled processes , This means that a printhead is used for the method according to the invention, which operates according to this method known per se in the prior art and generates the beam with this method. Parallel-controlled multi-nozzle systems can also be used. Printheads operating in accordance with such methods usually also have devices for deflecting the drops, with which they can be selectively directed to regions of the gemstone.

In a further embodiment of the invention, granular solids are distributed in the liquid material of the protective layer, preferably in the varnish, whereby the protective layer can settle uniformly on the gemstone without a meniscus of protective layer material forming over the facets in the case of a faceted ground gemstone , so areas of the protective layer with arched surface, and the edges between the facets remain free of protective layer.

A disadvantage here is that too high content of such solids represent these inhomogeneities, which can be germ cells for corrosion and are also visually recognizable in small gemstones.

Is now - as provided in a further embodiment of the invention - the protective layer forming material, in particular the paint, first applied with omission of gaps on the gemstone, and this applied material after application at least partially hardens or by curing until stiffened to some degree before further material forming the protective layer is applied, it is prevented that a contiguous meniscus, that is a continuous curved surface, can form over an entire facet or over a larger area of a gemstone. The gaps between two drops applied to the gemstone, which are not yet provided with a protective layer, can now be filled with additional protective layer material. Since these gaps are significantly smaller than the entire areas of the gemstone to be provided with a protective layer, the curvature resulting from the surface tension of the protective layer is significantly lower.

In the area of the edges between two facets of a gemstone and in the region of a tip, a relief of the partially hardened or hardened droplets of the protective layer material forms, which is subsequently filled by the material of the protective layer which covers the edge. If the protective layer forming material applied evenly over an edge or a tip of the gemstone, it may happen that forms over the edge or over the tip of a curved surface of protective layer material, which breaks during the curing, so that these areas ultimately not with a protective layer are provided. By initially providing protective layer material on both sides of the edge or tip, omitting the edge or the tip, the areas of the edge or tip are only dripped or irradiated after at least partial hardening of the previously applied protective layer material with liquid protective layer material be, the curvature is significantly lower, so that the above-mentioned damage in the region of the edge or the tip is avoided. In this case, it is also possible to dispense with separate solid-state additives in the liquid protective layer material, or these solid-state additives can at least be significantly reduced, since the hardened or partially hardened drops of the protective layer material represent a replacement of these solid bodies.

The curing or crosslinking of the protective layer material can be effected by application of radiation, in particular UV radiation, or by local heating or cooling. In the case of a protective layer in the form of a lacquer layer, UV or thermosetting lacquers known per se, such as those known per se, may be used. One-component paints are used. It is also possible to use two-part paints that cure by contacting with a second curing-initiating or accelerating component. This second component can be applied to the gemstone simultaneously with or after the application of the first component. For hardening by cooling, it is possible to add to the protective layer material substances which melt during the application of the protective layer and thereby cool and harden it. The curing process may include one or more process steps. Combinations of the stated curing methods and aids, which are known per se in the art, are also possible.

It can also be provided that solvents and / or dispersing agents are admixed to the material before application to the gemstone and the curing takes place by evaporation of these solvents or dispersing agents. Such paints are commonly known as solvent paints. It is also possible to use stoving enamels, e.g. Dispersions in which the curing takes place by thermal influence and / or evaporation of solvents or of dispersing agents.

Since the inventive method is characterized in that the material forming the protective layer can be applied very precisely to the desired areas of the gemstone, it is possible, for example, edges between facets of a gem and tips of a gem or the edge of the mirror layer by locally enhanced order of Protective layer material to protect evenly. In one embodiment of the invention Method are therefore the parameters of the coating process, preferably the amount of material to be applied and / or the parameters of curing depending on the geometry of the gem, in particular those areas to which the protective layer is to be applied selected. These sizes, on which the selected parameters depend, include, for example, the positional position and orientation of rondists, edges between facets and tips of the gemstones, or the edge of the mirror layer. For this purpose, the geometry of the gems can be stored in an electronic memory and preferably used to determine the parameters of the coating process automatically.

It can be provided a scanning device, with which the geometry of the gemstone and / or the Spiegeischirht is detected and stored in an electronic memory. With this information, as stated above, the coating is adapted to the critical locations. This adaptation by selecting the parameters of the coating process can be done automatically with an electronic data processing system.

In one embodiment of the invention, gemstones having tip-tapered regions are provided with a protective layer as described above. However, the tapered areas do not necessarily converge to a peak. Namely, it can also be provided to coat gemstones with a taper formed in the form of a stump, for example a pyramidal or truncated cone. In this case, the material forming the protective layer is applied in liquid form at least in sections to the outside of the tapered regions on which the mirror layer is also arranged. On these tapered areas, the mirror layer is arranged. The tapered portions are arranged obliquely with respect to the imaginary surface having the largest cross section.

However, it can also be provided to arrange the material forming the protective layer at least in sections on a mirror layer, which in turn is mounted on a plane parallel to the imaginary surface through the Rondiste or to the panel of the gemstone. For example, this may be a gem known as Rose.

The invention further relates to a gemstone having a front side and a back side, wherein the rear side is at least partially, preferably for the most part, provided with a mirror layer and wherein at least on or over the edge of the mirror layer, a protective layer is applied. The protection view covers or thereby covers the edge of the mirror layer. When covering the same time, the back of the end of the mirror layer as well as the gemstone directly or below the mirror layer on the gemstone layers arranged covered and protected. The protective layer may have been applied in particular by a method as described above.

By now providing that the edge of the protective layer is formed by hardened drops of the protective layer-forming, applied in liquid form material, the edge of the mirror surface, which is particularly sensitive to corrosion and other external environmental influences, can be protected. It can be provided that the edge of the protective layer consists of individually cured drops of the liquid protective layer material, or that the applied drops of the protective layer flow into each other and then harden. The edge of the protective layer according to the invention consists in this case of coagulated and then hardened drops. In contrast, a gemstone with a mirror surface on which a protective layer is arranged, whose edge is formed by breaking the gem out of a larger contiguous protective layer, jagged and uneven edge areas. Moreover, due to breaking out of a larger layer, the edge of the protective layer may even be formed so that the edge of the mirror surface is exposed or even the mirror layer is partially detached from the gem during breakout.

The gemstone according to the invention thus has on the edge of the mirror surface on a smooth conclusion, for example in the form of a bead or a semi-bead, which is unbroken or has arisen without breaking the paint layer. An edge that is not formed by hardened drops but by breaking out of a larger layer, has a jagged and not smooth course.

It is preferably provided that the edge of the mirror surface is arranged in the region of the Rondiste, which separates the front of the back of the gem. In order to achieve a particularly good protection of the mirror layer, it is preferably provided to arrange the protective layer or the edge of the protective layer over the edge of the mirror layer, whereby the edge of the mirror layer is covered by the protective layer and the protective layer protrudes beyond the mirror layer. The protective layer can also protrude slightly above the Rondiste and overlap on the front. This also a protection of the Rondiste is possible. By the edge of the protective layer is formed by a plurality of hardened drops, a uniform arrangement of the protective layer is possible.

In a preferred embodiment of the invention, the protective layer is arranged on the entire mirror layer, wherein in particular the edge of the protective layer is formed by hardened drops. Since the mirroring of the mirror layer faces the gemstone, the protective layer is arranged on the side of the mirror layer facing away from the gemstone, that is to say the rear side of the mirror layer.

Preferably, it is further provided that the protective layer is a lacquer layer, ie consists of lacquer or at least comprises lacquer.

The gems themselves consist in one embodiment of the invention made of glass, which meets the optical requirements for a gemstone, but is still inexpensive to manufacture. But it is also possible to use natural or synthetic gems or semi-precious stones for the invention.

The gemstone can be ground faceted, creating special refraction effects on the edges between the facets, which are caused in particular by the light reflections on the protected by the protective layer mirror layer. The mirror layer can be arranged on tapering areas which converge to form a point. Examples of such gems are chatons. However, the mirror layer can also be arranged on an imaginary surface through the Rondiste or to the panel arranged parallel surface. Examples of such gems are known as roses.

In a further preferred embodiment of the invention, at least the side of the mirror layer which faces the gemstone is mirrored, so that those light rays which pass through the front side, which faces away from the mirror layer, and reflects on the back side, on which the mirror layer is mounted become. The mirroring serves in this case, for example, to increase the brilliance of the gem. The facing away from the gemstone side of the mirror layer, so the back, is provided with the protective layer according to the invention.

Fig. 1

eine schematische Querschnittsdarstellung eines mit einem Verfahren des Standes der Technik beschichteten Schmucksteins,

Fig. 2

eine schematische Darstellung wesentlicher Elemente eines Verfahrens des Standes der Technik,

Fig.3

eine schematische Querschnittsdarstellung eines mit einem erfindungsgemäßen Verfahren beschichteten Schmucksteins,

Fig. 4

eine schematische Darstellung wesentlicher Elemente des erfindungsgemäßen Verfahrens,

Fig. 5a und 5b

schematische Querschnittsdarstellungen entlang zweier Schnittebenen eines mit einer Ausführungsform des erfindungsgemäßen Verfahrens beschichteten Schmucksteins,

Fig. 6a bis 6d

schematische Querschnittsdarstellungen entlang zweier Schnittebenen eines Schmucksteins während zweier Schritte einer anderen Ausführungsform des erfindungsgemäßen Verfahrens, und

Fig. 7a und 7b

schematische Querschnittsdarstellungen entlang zweier Schnittebenen eines Schmucksteins, beschichtet mit einer weiteren Ausführungsform des erfindungsgemäßen Verfahrens, und

Fig.8

schematische Querschnittsdarstellung einer weiteren Form eines Schmucksteins beschichtet mit einem erfindungsgemäßen Verfahren.

Further details and advantages of the present invention will be explained in more detail below with reference to the description of the figures with reference to the drawings. It shows:

Fig. 1

a schematic cross-sectional view of a gem coated with a method of the prior art,

Fig. 2

a schematic representation of essential elements of a method of the prior art,

Figure 3

a schematic cross-sectional view of a coated with a method according to the invention gemstone,

Fig. 4

a schematic representation of essential elements of the method according to the invention,

Fig. 5a and 5b

schematic cross-sectional views along two sectional planes of a gem coated with an embodiment of the method according to the invention,

Fig. 6a to 6d

schematic cross-sectional views along two sectional planes of a gemstone during two steps of another embodiment of the method according to the invention, and

Fig. 7a and 7b

schematic cross-sectional views along two sectional planes of a gemstone, coated with a further embodiment of the method according to the invention, and

Figure 8

schematic cross-sectional representation of another form of a gem coated with a method according to the invention.

Fig. 1 shows in a schematic cross-sectional view along a sectional plane perpendicular to the Rondiste 11 and perpendicular to the panel 20 of a gem 1 whose back 2 is at least partially provided with a mirror layer 4 on which a lacquer layer 6 for protecting the mirror layer 4 with a method according to the prior Technique has been applied. The front side 3 of the gemstone 1 is provided with neither a mirror layer 4 nor a lacquer layer 6. The front side 3 of the gemstone 1 is during the application of the lacquer layer 6 in a thermoplastic material, which serves as a holding device 13, arranged and thereby covered. The lacquer layer 6 is sprayed in the form of a spray 14 on the back 2 of the gemstone 1, whereby the holding device 13 is mitlackiert. When removing the gemstone 1 from the holding device 13, there are breakages 7, 7 'at an edge region of the gemstone 1, which is arranged in the region of the edge of the gemstone 1 between the front side 3 and the back side 2 of the gemstone 1. It may happen that also areas of the mirror layer 4 are exposed. In case of Fig. 1 can be seen at the break points 7, 7 'that the location of the break point 7, 7' can not be planned or controlled. At the break point 7, the lacquer layer 6 has been further removed from the mirror layer 4 before the lacquer layer 6 is broken than at the break point 7 '. These exposed areas represent germ cells for the corrosion, whereby the mirror layer 4 is ultimately destroyed or at least adversely affected in an optically disadvantageous manner. The edge of the protective layer 6 is formed by breaking points 7, 7 'and therefore not by hardened drops of the liquid-applied material of the protective layer. As a result, a broken course of the completion of the protective layer 6 is given, which can represent a starting point for corrosion. In particular, the edge 21 of the mirror layer 4, which is arranged in the region of the Rondiste 11, is not protected and thus endangered, destroyed or at least affected.

Fig. 2 shows a method of the prior art for coating gemstones 1 with a protective layer 6. The gems 1 are arranged in a holding device 13, consisting of a carrier with recesses. In the form of a spray 14, paint is sprayed over a large area onto the gemstones and the holding device 13 from a spray nozzle 15. The drops of the paint 5 thereby move chaotically within the spray 14, so that a targeted application of the paint 5 to the gems 1 is not possible. this applies in particular for satellite drops 17, which move completely irregularly and indefinitely outside of the actual spray 14. In order to be able to remove the gemstones 1 from the holding device 13, the lacquer layer 6 on the gemstones 1 must be at least partially cured. Because of the large-area spray 14 but forms a coherent lacquer layer, which is arranged in addition to the lacquer layer 6 on the gemstones 1 on areas 16 of the holding device 13. For this coherent layer, the gemstones 1 must be broken for removal from the holding device 13, whereby the break points 7, 7 'occur with the disadvantages mentioned above.

The cross-sectional view along a sectional plane perpendicular to the Rondiste 11 and perpendicular to the panel 20 of the gemstone 1 of Fig. 3 represents a gemstone 1, the back 2 has a mirror layer 4, which was provided with a method according to the invention with a serving as a protective layer 6 lacquer layer. The mirrored side of the mirror layer 4 is facing the gemstone 1, while the back of the mirror layer 4 faces away from the gemstone. Due to the precise application of the lacquer layer 6 by means of the inventive application with liquid paint drops 5, the holding device 13, in which the gemstone 1 with its front side 3 as in Fig. 1 is held during the application of the lacquer layer 6, not co-lacquered. The protective layer 6 is applied over the full area to the back 2 of the gem 1 and thereby in particular over the entire surface of the back of the mirror layer 4. The edge 21 of the mirror layer 4 is covered by the protective layer 6. In addition, the paint drops 5 impinge at a substantially right angle on the imaginary interface through the Rondiste 11 between the front 3 and back 2, in the vicinity of the edge 21 of the mirror layer 4 is arranged. For this reason, undisturbed completion of the lacquer layer 6 by hardened drops 5 forms at the boundary regions between the front side 3 and the back side 2, so that breaking out of a continuous lacquer layer during removal of the gemstone 1 from the holding device 13 is not necessary. It is thus an unbroken and mechanically undisturbed edge of the lacquer layer 6 at the edges of the gem 1 in the region of the Rondiste 11 and in the region of the edges of the mirror layer 4 possible. In this case, an overlap of the mirror edge, ie, the edges of the mirror layer 4 through the protective layer 6 is possible, creating a particularly high Corrosion protection is given. It can be seen further that the applied paint drops 5 are cured before merging. This curing is possible due to the selective, targeted irradiation of the method according to the invention. An inadvertent linting of the paint on larger areas of the front side 3 of the gems can be prevented and still a cover of the mirror layer 4 at the edge regions of the Rondiste 11 are made possible.

Fig. 4 shows a schematic view of essential steps and elements that are necessary for carrying out an embodiment of the method according to the invention. In or on the holding device 13 ', a plurality of gemstones 1 is arranged, each having a mirror layer 4 on its back 2. A first gemstone 1 has already been provided with a lacquer layer 6, while a second gemstone 1 has no such protective layer 6. From a print head 12, which has a plurality of nozzles, each with an outlet opening, a resist layer 6 is applied as a protective layer 6 on the mirror layer 4 by the mirror layer 4 is dripped with paint drops 5. The paint droplets 5 have velocity vectors with essentially the same direction, the direction of the velocity vector being oriented perpendicular to the surface of the transfer film 13 '. At the margins of the mirror layer 4 in the region of the Rondiste 11 harden the drops and protrude partially over the edge of the Rondiste 11 in the region of the front side 3 of the gem 1. The edge of the protective layer 6 is therefore as a bead around the Rondiste 11 and thus formed around the edge 21 of the mirror layer 4.

By the application method according to the invention breaking out of the gemstone 1 from a continuous lacquer layer 6 is not necessary and the edge of the protective layer 6 is formed as a smooth and unbroken edge, whereby an optimum of protection is given. In addition, no liquid protective layer material flows to further areas of the front side 3 of the gem 1. It is preferably provided that the mass of the drops 5 is essentially the same size, so that they are applied to the gemstone 1 with substantially the same momentum.

Although for the inventive method a holding device 13, as in Fig. 2 could be used, since co-painting of the holding device 13 due to the selective irradiation can be avoided, in this figure, the holding device 13 is designed as a transfer film. In a method of the prior art, the spray 14 would cause areas of the front side 3, which are not to be provided with a lacquer layer 6, to be coated, since due to the undefined pulse the paint drops 5 in a spray 14, in particular the satellite drops 17 This unwanted coating automatically occurs. Due to the targeted application of the back 2 of the gem 1 with liquid paint drops 5, all substantially the same direction of movement during application, this disadvantage does not occur and it forms an undisturbed mechanical completion of the paint layer 6 in the form of hardened drops 5 at the Rondiste 11 of gemstone 1. A transfer film has over a holding device 13 with recesses the advantage that the gems can be easily arranged on the holding device and removed again.

The elements of the print head 12 itself are not shown. The paint drops 5 can be generated by means of a piezo-inkjet process. Instead, it is also possible to use valve-controlled printheads or printheads that operate according to the bubblejet method. Since such printheads are known per se in the art for inkjet printers for office or industrial purposes, has been omitted for reasons of clarity on a representation of components of the printhead itself.

Fig. 5a shows a schematic cross section of a gemstone 1 along a cutting plane perpendicular to the Rondiste 11 and perpendicular to the panel 20, coated with another embodiment of the method according to the invention, wherein the edge of the protective layer 6 unbroken and smooth. The uniformly applied in the form of droplets 5 material of the protective layer 6 flows in this embodiment of the invention into each other before it hardens, resulting in a pronounced curvature, a so-called meniscus, on the side surfaces of the back 2 of the gem 1 due to the surface tension. In this case, the tip 18 of the gemstone 1, the protective layer 6 partially tear, resulting in a poorer coverage of the pointed area result. The edge of the protective layer exists from interleaved and then hardened drops 5 of protective layer material. Due to the targeted and directed application, the applied drops 5 but hang on the Rondiste 11 of the gem due to surface tension and other physical effects, so that no coherent protective layer on the holder 13 and the gemstone 1 forms and breaking out of the gemstone 1 from this layer is not necessary.

As the schematic cross-sectional view along a sectional plane through the back 2, parallel to the Rondiste 11 and to the panel 20 of the gemstone 1 of Fig. 5b shows, this phenomenon of the poorer edge coverage partly also arises at the edges between the facets of the facetted gemstone 1.

In the areas arranged on the rear side 2, which adjoin the Rondiste11, the edge 21 of the mirror layer 4 is arranged, on which inter alia, the protective layer 6 forming material is applied. In particular, when the gemstone 1 with its front side 3 in a recess which serves as a holding device 13, during the application of the protective layer 6 is arranged and the coated gemstone 1 must be torn out of the holding device below, the edge 21 of the mirror layer 4 is at risk.

Fig. 6a shows a schematic cross-sectional view along a sectional plane perpendicular to the Rondiste 11 and perpendicular to the panel 20 of the gemstone 1 after a first process step of another embodiment of the method according to the invention. There are first drops of protective layer material 5, so for example paint, has been applied to the back 2 of the gem 1 with omission of gaps 19.

Fig. 6b shows this in a schematic cross-sectional view along a sectional plane through the back 2, parallel to the Rondiste 11 and to the panel 20 of the gemstone 1. Before now further protective layer material 6 'in the form of targeted drops selectively applied to the gemstone 1, the already applied Regions of the protective layer 6 at least partially cured. Therefore It may be provided to irradiate the gem 1 with UV radiation or suspend a heat / cold treatment.

In a further method step, the gaps 19 are now filled with further protective layer material 6 '. This filling can be done selectively or without attention to the position of the gaps 19, so evenly. Due to the dimensions of the gaps 19, the curvature, ie the meniscus, is significantly smaller due to the surface tension of the liquid protective layer material 6 '. The edge of the protective layer 6 consists in this case at least partially of individual hardened drops 5 and has, as in the case of Fig. 5a and 5b no breakage on.

In addition, this is a significantly improved edge coverage - as based on the cross-sectional view along a sectional plane through the back 2, parallel to the Rondiste 11 and to the panel 20 of the gem 1 of Fig. 6d it can be seen - and a significantly improved coverage of the tip 18 is possible, since the edges and the tip 18 may be parts of the gaps 19 in the first step. The already hardened areas of protective layer material 6 applied with the omission of gaps 19 serve as solid bodies for the further applied protective layer material 6 'which, like the protective layer 6, is applied according to a method described above.

Fig. 7a shows in a schematic cross-sectional view along a sectional plane perpendicular to the Rondiste 11 and perpendicular to the panel 20 of the gem 1, as in a further embodiment of the method according to the invention, the coverage of the tip 18 of the gem 1 is improved. In an electronic memory data of the gem 1, so for example, the geometry and locations of the tip 19 and other edges and the extent and the edge 21 of the mirror layer 4 are stored. For the in Fig. 7a coated gemstone 1 has been dispensed with an application of the protective layer 6 omitting gaps 19, which is why a fairly pronounced curvature on the side surfaces of the gemstone 1 exists. In order to improve the coverage of the tip 18 and the edges between the facets, in a second process step, the tip 18 and the edges between the facets of the gemstone 1 are selectively dropped with further liquid protective layer material 6 ', so that their coverage is improved.

Fig. 7b shows this for the edges between the facets in a cross-sectional view along a sectional plane through the back 2, parallel to the rondist 11 and to the panel 20 of the gemstone.

In this case, the edge 21 of the mirror layer 4 is even better covered with the protective layer 6.

FIG. 8 shows a gem known under the name Rose 1, the back 2 is completed with a parallel to the panel 20 surface 22. On the surface 22, a mirror layer 4 is arranged, which has been completely coated with a protective layer 6 according to the inventive method, so that the edge 21 is covered with the protective layer 6.

It should be noted that in the illustrated figures to illustrate the advantages of the invention, the protective layer and the drops 5 of the protective layer 6 are significantly enlarged and shown only schematically. This also applies to the dimensions and size relationships of the illustrated gemstones, which may have a deviating from the illustrated embodiments of a Chatons or a rose shape. In general, arbitrarily shaped gemstones in a process according to the invention can be coated or coated with a protective layer.

Claims (16)

Process for coating at least one, in particular faceted, ground gemstone (1) with a protective layer (6), the gemstone (1) being held by a holding device (13) and at least partially provided with a mirror layer (4) and the die Protective layer (6) forming material in liquid form is at least partially applied to the mirror layer (4) and then cured, characterized in that the protective layer (6) forming material in the form of drops (5) is applied, wherein the gemstone (1) applied drops (5) are applied in substantially the same direction on the gemstone (1). A method according to claim 1, characterized in that the protective layer (6) forming material is at least partially applied to the edge (21), preferably on the entire edge (21), the mirror layer (4). A method according to claim 1, characterized in that the material forming the protective layer (6) is applied to the mirror layer (4) omitting areas of the edge (21) of the mirror layer (4) and the omitted areas of the edge (21) of the mirror layer (4) are removed from the gemstone (1) in such a way that the protective layer (6) covers or covers the newly formed edge of the mirror layer (4). Method according to one of claims 1 to 3, characterized in that the gemstone (1) is held in or on a support surface of the holding device and the drops (5) applied in a direction perpendicular to the carrier surface of the holding device (13) on the gemstone substantially become. Method according to one of claims 1 to 4, characterized in that the protective layer (6) forming material is applied to the entire mirror layer (4) of the gem (1). Method according to one of claims 1 to 5, characterized in that the gemstone (1) with the protective layer (6) forming material from an outlet opening of a nozzle, preferably from outlet openings of a plurality of nozzles, a printhead (12) is irradiated. Method according to one of claims 1 to 6, characterized in that in the liquid state of aggregation of the protective layer (6) forming material, preferably the paint, solid bodies are distributed. Method according to one of claims 1 to 7, characterized in that the protective layer (6) forming material is first applied with omission of gaps (19) on the gemstone (1) and the first applied areas of the protective layer (6) forming material at least partially harden before the gaps with other, the protective layer (6) forming material are filled. A method according to claim 8, characterized in that the curing of the protective layer (6) forming material by application of radiation, in particular UV radiation, or by heating or cooling and / or by adding a reactive component takes place. Method according to one of claims 1 to 9, characterized in that the parameters of the coating process, preferably the amount of material to be applied and / or the parameters of the curing, depending on the geometry of the gemstone (1) are selected. A method according to claim 10, characterized in that a scanning device is provided, with which the geometry of the gemstone (1) is detected and stored in an electronic memory and the selection of the parameters of the coating process is automated. Method according to one of claims 1 to 11, characterized in that the gemstone (1) in the direction of a tip (18) has tapered portions, wherein the protective layer (6) forming material in liquid form at least partially on the outside of the tapered Areas is applied. Gemstone with a front side (3) and a back side (2), wherein the rear side (2) at least partially, preferably for the most part, with a mirror layer (4) is provided and wherein at least the edge (21) of the mirror layer (4) with a protective layer (6) is covered or covered, in particular by a method according to one of claims 1 to 12 applied, characterized in that the edge of the protective layer (6) by hardened drops of the protective layer (6) forming, applied in liquid form material is formed and / or formed by curing of the gemstone (1) into each other flowed drops of the protective layer (6) forming, applied in liquid form material. Gemstone according to claim 13, characterized in that the protective layer on the entire mirror layer (4) is arranged. Gemstone according to one of claims 13 or 14, characterized in that the gemstone (1) consists of glass or comprises glass and / or is ground facetted. Gemstone according to one of claims 13 to 15, characterized in that the mirror layer (4) has a mirrored side facing the gemstone (1), wherein the protective layer (6) on the side facing away from the gemstone (1) side is arranged.

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