EP3927548A1

EP3927548A1 - Printing method and product thereof

Info

Publication number: EP3927548A1
Application number: EP20760259.0A
Authority: EP
Inventors: Zhi JIANG; Meng YU; Sijin SHU
Original assignee: Giesecke+Devrient Mobile Security Germany GmbH
Current assignee: Giesecke and Devrient ePayments GmbH
Priority date: 2019-02-20
Filing date: 2020-02-15
Publication date: 2021-12-29
Also published as: EP3927548A4; CN109677149A; WO2020168988A1

Abstract

A printing method is disclosed. The method comprises the steps of : forming an ink layer (11) on a surface of an object (10) by spraying ink; curing the ink in the ink layer (11); and after the ink is cured, forming a hot stamping material layer (12) on the ink layer (11) by hot stamping. In addition, a product obtained by the printing method is disclosed.

Description

PRINTING METHOD AND PRODUCT THEREOF

TECHNICAL FIELD

The present application relates to a printing technology, and more particular relates to a printing method capable of making a metal slice stereoscopic and a product manufactured by the printing method.

BACKGROUND

Metal slices (metal labels) with stereoscopic feeling and metallic luster are widely used in the fields of films, electronic products and the like, and are especially used for making logo, trademarks, names and the like on various cards and paperboard. The metal slice is usually coated on both sides in advance and held between a transparent film and a release paper. When it is necessary to attach the metal slice, it is needed to manually peel off the release paper, align the metal slice to a predetermined attaching position, then press the transparent film to adhere the metal slice, and finally peel off the transparent film. The traditional process of attaching metal slices can be realized manually or automatically through equipments. However, manual operation has the problems of low efficiency, poor positioning precision, large fluctuation of adhering quality, high rejection rate of manual film stripping, and the like. Even if the operation of automatically adhering metal slices is carried out through equipment, the following problems still exist: the cost of metal materials is high; it is difficult to control incoming materials consistency, resulting in an increase in failure rate; and when peeling off the release paper, it may easily cause metal slices to peel off, resulting in an increase in rejection rate.
Hot stamping (gilding) technology is one of printing technologies. It uses a certain pressure and temperature to press an article to be hot stamped or a surface of the article on a hot stamping die in a short time, so as to transfer a metal foil or a color foil to the surface of the article to be hot stamped according to pre-formed pictures and texts on the hot stamping die. The hot stamping includes a planar hot stamping and a stereoscopic hot stamping. However, the metal foil used in the planar hot stamping is thin, which makes it difficult to obtain stereoscopic visual effect, and the stereoscopic hot stamping is usually only suitable for some specific materials and its application scope is limited.
In order to make the hot stamping pattern stereoscopic, a printing process for hot stamping on an ink layer has already appeared. In this process, a layer of ink is usually silk-screen on a surface of an object to be hot stamped, and after the ink is cured, a layer of metal foil is hot stamped on the ink layer protruding from the surface of the object, so that the metal foil looks to have visual effect of stereoscopic relief. However, the silk-screen printing requires plate making in advance, and a set of silk-screen printing plates need to be made correspondingly for each different pattern, so the cost is high and the process is complicated. In addition, a thickness of the printing ink is only about 10 microns each time in the silk-screen printing process. In order to precisely realize printing of ink with a certain thickness, the silk-screen printing is often required many times, so the efficiency of silk-screen printing is very low. In addition, edges of the silk-screen printing ink layer are neat, after a hot stamping material layer is further added on the ink layer, the difference between heights of a top surface of the hot stamping material layer and the surface of the object is further increased, and subsequently when the surface of the object after the hot stamping is covered with a protective film, air gaps or bubbles easily remain at an crossing angle between the edges of the hot stamping material layer and the ink layer and the surface of the object, which not only affects the appearance, but also easily leads to the separation of the protective film from the surface of the object.
SUMMARY
he object of the application is to provide a printing method, which can make the metal slice look stereoscopic while solving the problems in the prior art.
According to an aspect of the present application, a printing method is provided.
According to an exemplary embodiment, the printing method may include forming an ink layer on a surface of an object by spraying ink; curing the ink in the ink layer; and after the ink is cured, forming a hot stamping material layer on the ink layer by hot stamping.
According to another exemplary embodiment, the ink includes UV ink, and the step of curing the ink in the ink layer may include curing the UV ink using ultraviolet light.
According to another exemplary embodiment, the UV ink may include UV varnish.
According to another exemplary embodiment, an edge of the ink layer may have a first slope.
According to another exemplary embodiment, the ink layer may include a first area having a first thickness and a second area having a second thickness, and the first thickness is different from the second thickness.
According to another exemplary embodiment, there may be a second slope between the first area of the ink layer and the second area of the ink layer.
According to another exemplary embodiment, the step of forming the hot stamping material layer on the ink layer may include hot stamping a hot stamping material on the ink layer by a soft press roller, and the hot stamping material layer covers at least a first area, a second area, and a second slope of the ink layer.
According to another aspect of the present application, there is also provided a product manufactured by using the method of any of the above embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects and advantages of the present application will be apparent from the following detailed description of the application with reference to the accompanying drawings, in which:
Fig. 1 is a schematic flow chart of a printing method according to an embodiment of the present application;
Fig. 2 is a schematic structural diagram of a product obtained by using a printing method of one embodiment of the present application; and
Fig. 3 is a schematic structural diagram of a product obtained by a printing method of another embodiment of the present application.

DETAILED DESCRIPTION

In order to make the object, technical scheme and advantages of the application easier to understand, the following will further explain the technical scheme of the application in detail with reference to the drawings and exemplary embodiments. It should be noted that this application is not limited to the constructions or details set forth below or illustrated in the drawings. The application may also include other embodiments or be implemented in other ways.
It should be understood that the wordings "including" , "comprising" and "having" used in this specification do not exclude other elements or steps, and the orientation terms used herein, such as "left" , "right" , "upper" , "lower" , etc., are only used to indicate the direction or orientation of corresponding features in the drawings for ease of explanation and understanding, and should not be interpreted as limiting the structure of this application. The prefixes "first" , "second" and "third" of technical features used in this application document are only used to distinguish different similar technical features and do not attempt to make additional restrictions on each technical feature. In addition, the drawings of the present specification are merely schematic, and the dimensions and dimensional proportions of components do not represent the true dimensions and proportions of the products, but merely for the purpose of schematically presenting the position relationship or the connection relationship between the parts. In order to facilitate drawing and understanding, the dimensions of the components may be scaled in different proportions.
According to an aspect of the present application, a printing method is provided. Fig. 1 shows a schematic flow chart of a printing method according to one embodiment of the present application. As shown in Fig. 1, the printing method includes: forming an ink layer on a surface of an object by spraying ink; curing the ink in the ink layer; and forming a hot stamping material layer on the ink layer by hot stamping.
By replacing a silk-screen printing process with a spraying process, the step of silk-screen printing can be omitted, the process can be significantly simplified and the cost can be reduced. The spraying of ink can be achieved by a precision spraying equipment (for example, an ultrasonic atomizing precision spraying equipment) . A style of spraying (ashape of the ink layer formed by spraying) can be set through an interactive interface of the spraying equipment. For example, the shape of the ink layer to be formed by spraying can be determined by image recognition, then be processed into parameters and/or instructions recognizable by a computer or the spraying equipment by an image processing software and be input to the spraying equipment. For a complex relief modeling (in which for example, different areas are of different heights) , the use of silk-screen printing process requires manufacturing multiple silk-screen printing plates. However, by using an automatic spraying equipment, various complex relief modeling can be formed at one time by properly setting the spraying path. Therefore, the step of forming the ink layer can be significantly simplified. In addition, precision spraying processes, such as ultrasonic atomization spraying processes, can form extremely tiny (micron-sized) mist droplets, which will be dried and cured in a very short time even under natural conditions. Furthermore, a movement rate of a spray head or a spray flow rate or the like can be simply set to realize different thicknesses of the ink layer without performing the silk-screen printing several times, so that the production efficiency can be remarkably improved.
In a preferred embodiment, the ink used to form the ink layer includes ultraviolet curing ink (UV ink) . By using an ultraviolet curing device, the UV ink can be cured almost instantaneously, and the next process can be directly carried out without waiting time. The UV ink may be transparent or have various desired colors. In an exemplary embodiment, the UV ink comprises a transparent UV varnish. By forming the ink layer using the UV varnish, the ink layer can be cured quickly, and due to the transmittance of the UV varnish, it will not block the color and/or the pattern of the object surface below it, so that visually, the hot stamping material layer floats on the surface of the object and is more stereoscopic.
Fig. 2 shows a schematic structural diagram of a product obtained using a printing method according to the present application. As shown in Fig. 2, an ink layer 11 is formed on the surface of an object 10 to be printed by spraying ink. After the ink in the ink layer 11 is completely cured, a hot stamping material layer 12 is formed on an upper surface (asurface facing away from the object 10) of the ink layer 11 by a hot stamping. The hot stamping material layer 12 is formed of a hot stamping material, which may include commonly used metal foils and color foils.
With continued reference to Fig. 2, an edge portion of the ink layer 11 has a first slope 111. The ink layer 11 is formed by a spraying process, and the edge of a spraying area gradually reduces the amount of ink outward due to the diffusion of atomized ink droplets. Therefore, the edge of the ink layer 11 forms a natural transition area whose thickness gradually decreases outward from the middle area of the ink layer, thus forming a slope. Those skilled in the art may understand that the slope is not necessarily a flat slope, but may be a slightly convex or slightly concave slope. In addition, a flatness of the slope is related to parameters such as dimension of the droplet of the atomized ink. Usually, the smaller the droplet dimension is, the better the flatness of the slope is.
In some embodiments, after the hot stamping, some objects need to be added with an additional protective film (not shown in the figure) on the hot stamping surface of the objects. In the case of forming the ink layer 11 by using the spraying process, since the edge of the ink layer 11 forms the slope 111, the protective film can be closely adhered to the slope surface of the ink layer 11, thus reducing the possibility of leaving air gaps or bubbles at the crossing angle between the edges of the hot stamping material layer 12 and the ink layer 11 and the surface of the object 10.
It should be noted that although the hot stamping material layer 12 covers only a planar surface portion of the ink layer 11 in Fig. 2, in other embodiments not shown, the hot stamping material layer 12 may partially or completely cover the sloping surface 111 of the edge of the ink layer 11. In the hot stamping step, a soft press roller (not shown in the figure) can be used for the hot stamping, and a surface of the soft press roller changes along with the surface shape of the ink layer 11, so that the hot stamping material is hot stamped on the central planar portion and the edge slope 111 of the ink layer 11.
Fig. 3 shows a structural schematic diagram of another product obtained using a printing method according to the present application. As shown in Fig. 3, an ink layer 21 is formed on an upper surface of the object 20. The ink layer 21 includes a first area A1 of a first thickness d1 and a second area A2 of a second thickness d2, and the first thickness d1 is different from the second thickness d2.
As described above, by appropriately setting the spraying path in the spraying apparatus, the ink layer 21 with areas of different thicknesses can be formed at one time. However, for the usual silk-screen printing process, a plurality of different silk-screen printing plates need to be manufactured, and this complex and special shape can only be realized by performing the silk-screen printing several times. Therefore, by using the spraying process, the step of forming the ink layer 21 can be significantly simplified.
Continuing with Fig. 3, in addition to the first slope 211 in the edge area of the ink layer 21, there is also a second slope 212 between the first area A1 of the ink layer 21 and the second area A2 of the ink layer 21. Referring to the above description in conjunction with the slope 111, those skilled in the art can understand that, based on the characteristics of the spraying process, when a second layer of ink is continuously sprayed on the local area on a first layer of ink formed by a spraying process, a second slope (area) will be formed between the first area A1 and the second area A2 due to the diffusion of the spray.
When the hot stamping is carried out on ink layer 21 with different heights, different areas of the formed hot stamping material layer 22 are also of different heights (as shown in Fig. 3) . Therefore, when viewed from the outside, the hot stamping material layer 22 after the hot stamping has an obvious three-dimensional shape, so the stereoscopic vision effect is more remarkable.
In order to enable the hot stamping material layer 22 to be fully combined with the first area A1 and the second area A2 of the ink layer 21 with different heights, the hot stamping may be performed by using a soft press roller. Therefore, the step of forming the hot stamping material layer on the ink layer may include hot stamping a hot stamping material on the ink layer 21 by using the soft press roller, and the hot stamping material layer 22 covers at least the first area A1, the second area A2, and the second slope 212 of the ink layer 21. Further, since the second slope 212 exists between the first area A1 and the second area A2 of the ink layer 21, when a protective layer (not shown in the figure) is added to an outer surface of the hot stamping material layer 22, the protective layer can be closely adhered to the second slope 212 of the ink layer 22, thereby reducing the possibility of leaving bubbles between the first area A1 and the second area A2 of the hot stamping material layer 22 with different heights.
Another aspect of the present application also relates to a product obtained using the above printing method. The products include any kind of products suitable for using the printing method described in this application in its manufacturing process, including but not limited to books, passports, identification cards (identity documents, financial transaction cards, etc. ) , flat prints, various arts and crafts, etc.
Thus far, the preferred embodiments of the present application have been described in detail by way of example, but those skilled in the art will recognize that further modifications and changes can be made thereto without departing from the spirit of the present application, and all such modifications and changes should fall within the scope of protection of the present application. Therefore, the scope of protection of this application shall be subject to the scope of protection of the said claims and their equivalent technical solutions.

Claims

A printing method comprising:

forming an ink layer on a surface of an object by spraying ink;

curing the ink in the ink layer; and

after the ink is cured, forming a hot stamping material layer on the ink layer by hot stamping.
The printing method according to claim 1, wherein the ink includes UV ink, and the step of curing the ink in the ink layer comprises curing the UV ink using ultraviolet light.
The printing method according to claim 2, wherein the UV ink comprises UV varnish.
The printing method according to claim 1, wherein an edge of the ink layer has a first slope.
The printing method according to any one of claims 1-4, wherein the ink layer comprises a first area having a first thickness and a second area having a second thickness, and the first thickness is different from the second thickness.
The printing method according to claim 5, wherein there is a second slope between the first area of the ink layer and the second area of the ink layer.
The printing method according to claim 6, wherein the step of forming the hot stamping material layer on the ink layer comprises hot stamping a hot stamping material on the ink layer by a soft press roller, and the hot stamping material layer covers at least the first area, the second area and a second slope of the ink layer.
A product manufactured by the printing method according to claims 1-7.