A security pattern preparation system

Abstract

The application provides a security pattern preparation system, which comprises a printing substrate with an inducible ink coating printed on the surface, and at least one set of imaging light-magnetic double field and one set of curing light-magnetic double field for forming a variable security pattern on the surface of the printing substrate; the printing substrate is conveyed and sequentially passes through the light-magnetic double field and the curing light-magnetic double field; the imaging light-magnetic double field system comprises a light field and a magnetic field, which are arranged above and below the printing substrate respectively, the magnetic field is used for inducing the inducible ink coating of the printing substrate to form a magnetic field pattern, and the light field uses a transparent film as a pattern carrier and is used for curing the part of the ink coating corresponding to the pattern after being induced by the magnetic field; the curing light-magnetic double field comprises a curing light source and a curing magnetic field, the curing magnetic field can re-induce the part of the ink coating which is not irradiated by the light field, and the curing light source is used for curing the re-induced ink coating. The pattern prepared by the application has higher anti-counterfeiting degree.

Description

Technical Field

[0001] This invention belongs to the field of anti-counterfeiting printing technology, and particularly relates to a security pattern and its preparation system for use in the field of anti-counterfeiting. Background Technology

[0002] The magnetic optically variable security pattern jointly developed by VIAVI and Sicpa has a large number of patents registered by VIAVI for the application technology of magnetic optically variable ink. The most core one is 200480018382.5, filed in 2004, entitled "Method and apparatus for generating a pattern in a coating containing magnetic particles induced by a magnetic field". This technology has been applied to banknotes in many countries around the world. It is worth mentioning that the core technical elements of the security printing pattern formed by VIAVI and Sicpa are the printed pattern and the magnetic plate pattern.

[0003] The purpose of this invention is to explore a more complex banknote printing scheme and equipment with a higher degree of anti-counterfeiting. Summary of the Invention

[0004] The objective of this invention is achieved through the following technical solution:

[0005] A security pattern preparation system, characterized in that it comprises: a printing substrate with an inducible ink coating printed on its surface, and at least one imaging optical-magnetic dual field and one curing optical-magnetic dual field for forming a variable security pattern on the surface of the printing substrate; the printing substrate is conveyed and sequentially passes through the at least one imaging optical-magnetic dual field and the curing optical-magnetic dual field; the imaging optical-magnetic dual field system includes an optical field and a magnetic field, the optical field and the magnetic field being respectively disposed above and below the printing substrate, the magnetic field being used to induce the inducible ink coating on the printing substrate to form a magnetic field pattern, the optical field using a transparent film as a pattern carrier, being used to cure the portion of the ink coating induced by the magnetic field corresponding to the pattern; the curing optical-magnetic dual field includes a curing light source and a curing magnetic field, the curing light source and the curing magnetic field being respectively disposed above and below the printing substrate, or, one pole of the curing magnetic field being disposed above the printing substrate and the other pole being disposed below the printing substrate, such that the curing magnetic field can re-induce the portion of the ink coating not irradiated by the optical field, the curing light source being used to cure the re-induced ink coating.

[0006] Preferably, the light transmittance of the transparent film is 70-100%.

[0007] Preferably, one pole and the other pole of the fixed magnetic field are perpendicularly symmetrical with respect to the surface of the printing substrate, or are inclined with respect to the surface of the printing substrate.

[0008] Preferably, the parallel light source includes a light source and a parallel light lens, and the parallel light source is a UV light source or an EB electron beam; the corresponding inducible ink is a UV-curable ink or an electron beam-curable ink.

[0009] Preferably, the magnetic field and / or the second magnetic field is a permanent magnetic field, an electromagnetic field, or a tracked magnetic field; the permanent magnetic field or electromagnetic field is cylindrical, horseshoe-shaped, planar magnetic field, uniform magnetic field, motor-driven spherical cap magnetic field, or vertically superimposed magnetic field; the tracked magnetic field is a rubber magnetic track or a track with a magnetic plate clamped on it.

[0010] Optionally, the security pattern is a QR code and a variable code, the magnetic field is a fixed planar magnetic field, and the magnetic field distribution of the fixed planar magnetic field is the same in a certain area in the direction of movement; the magnetic field is used to induce the inducible ink coating of the printing substrate, and the pigment flakes in the corresponding ink coating are arranged in a plane; the light field is used to cure the part of the ink coating induced by the magnetic field that is irradiated by the light field.

[0011] Optionally, the light field is a variable light field, consisting of a parallel light source and a variable aperture. The light from the parallel light source is projected onto the surface of the printing substrate through the variable aperture. The parallel light source, parallel light lens, and variable aperture are arranged sequentially from top to bottom. The variable aperture is formed by a transparent film, a film drive system, and a fixed inkjet system and inkjet drying unit. The film drive system synchronously drives the transparent film and the printing substrate. The inkjet system and the inkjet drying unit work continuously, continuously outputting a variable aperture pattern to the surface of the driven transparent film. The light emitted from the parallel light source passes through the transparent film with the existing aperture pattern and is projected onto the surface of the printing substrate, so that the aperture pattern is transferred into the ink coating on the surface of the printing substrate.

[0012] Optionally, the light field includes a parallel light source and a fixed aperture. The fixed aperture is formed by a transparent film with a continuous pre-printed pattern that circulates at the same linear velocity as the printing substrate and a fixed light-shielding body. The light-shielding body has a light-transmitting slit. The transparent film moves through the light-shielding body. The parallel light source is positioned above the light-shielding body and sequentially projects through the transparent film and the light-transmitting slit onto the ink coating of the printing substrate, transferring the pre-printed pattern portion exposed on the transparent film by the light-transmitting slit of the light-shielding body into the ink coating on the surface of the printing substrate.

[0013] Optionally, the light field employs a fixed aperture, which includes a transparent film with a pre-formed continuous pattern and a parallel light source. The transparent film is transported at the same linear velocity as the printing substrate. When the transparent film is transported between the parallel light source and the printing substrate, the emitted light from the parallel light source is projected onto the ink coating on the surface of the printing substrate through the transparent film, thereby transferring the pattern into the ink coating.

[0014] Optionally, the light field is a pulsed aperture, including a parallel light source and a pre-patterned pulsed transparent film. The parallel light source is positioned above the transparent film. Each pulse of the transparent film causes one or more patterns on it to be positioned between the parallel light source and the printing substrate. The emitted light from the parallel light source is projected onto the ink coating on the surface of the printing substrate through the pattern of the transparent film, thereby transferring the pattern into the ink coating.

[0015] It should be particularly noted that when both the magnetic field and the curing magnetic field are positioned below the printed substrate, the poles of the magnetic field and the curing magnetic field are in opposite directions.

[0016] The principle of this invention is as follows: A parallel light source and a transparent film form a parallel light pattern with pattern information. The parallel light pattern is mapped onto an inducible ink coating on a printing substrate. The portion of the ink coating corresponding to the parallel light pattern is pre-cured. The photoinitiator in the liquid UV material of the pre-cured inducible ink coating is stimulated to become free radicals or cations, thereby initiating the polymerization of a polymer resin containing active functional groups into a solid state, which cannot be induced again by an external magnetic field. The printing substrate then passes through a second set of imaging light fields. The uncured pigments in the ink coating are oriented according to the field distribution of the second inducing magnetic field, and then pre-cured by the light field of the second set of imaging light fields. At this time, it is possible to enter a third set of imaging light fields... Finally, the pattern that has been pre-exposed multiple times is cured.

[0017] The principle of using EB electron beam ink is the same. After the patterned part is exposed by an electron beam, the high-energy electrons in the exposed part interact with the ink coating molecules, causing them to decompose into free radicals. Then, the free radicals react with C=C double bonds to form growth chains. Finally, the growth chains react with the remaining components of the coating ink to cause cross-linking of the cured coating and increase the cross-linking density.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] 1. The imaging light field uses transparent film with very little thickness and good light transmittance, making the boundaries of the pattern clearer. In addition, the film is flexible and bendable, so it can be moved synchronously with the printing substrate to adjust the distance between the film and the printing substrate.

[0020] 2. Since the light pattern used for exposure is controllable, each security pattern formed has a controllable difference, thereby fulfilling the requirements of machine-readable one-item-one-code or machine-readable invisible pattern for anti-counterfeiting and traceability.

[0021] In summary, the security pattern formed by this invention offers higher security, anti-counterfeiting capabilities, and stronger traceability. The anti-counterfeiting pattern formed by this invention is more complex and contains richer information; in practical applications, multiple sets of controllable exposure patterns and magnetic field patterns can be added to create even more complex anti-counterfeiting patterns, achieving a level of difficulty in replication. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the system structure according to Embodiment 1 of the present invention;

[0023] Figure 2 This is a schematic diagram of the optical field structure in Embodiment 2 of the present invention;

[0024] Figure 3 This is a schematic diagram of the system structure according to Embodiment 3 of the present invention;

[0025] Figure 4 This is a schematic diagram of the solidified optical-magnetic dual-field structure of Embodiment 5 of the present invention;

[0026] Figure 5 This is a schematic diagram of the planar fixed magnetic field structure in Embodiment Six of the present invention. Detailed Implementation

[0027] Example 1:

[0028] This embodiment provides a system for forming variable security patterns using both optical and magnetic fields, such as... Figure 1 As shown, it includes: a printing substrate 1 with an induced ink coating printed on its surface, and an imaging optical-magnetic dual field and a curing optical-magnetic dual field for forming a variable security pattern on the surface of the printing substrate 1.

[0029] The printing substrate 1 is conveyed by a conveying mechanism, sequentially passing through the imaging optical-magnetic dual field and the curing optical-magnetic dual field. The imaging optical-magnetic dual field system includes an optical field and a magnetic field, which are respectively positioned above and below the printing substrate 1. The magnetic field 2 is a synchronous magnetic field, which moves synchronously with the printing substrate 1 through the magnetic field conveying mechanism, i.e., moves at the same linear velocity. It is used to induce the inducible ink coating printed on the surface of the printing substrate 1 to form a magnetic field pattern. The optical field is used to cure the portion of the ink coating induced by the magnetic field that is irradiated by the optical field. The curing optical-magnetic dual field includes a curing light source 8 and a curing magnetic field 9, which are respectively positioned above and below the printing substrate 1. This allows the curing magnetic field 9 to re-induce the portion of the ink coating that was not irradiated by the optical field. The curing light source 8 is used to finally cure the ink coating of the entire patterned area. The curing light source 8 is projected vertically onto the ink coating of the printing substrate 1 from above.

[0030] Specifically, the magnetic field 1 and / or the solidified magnetic field 9 are permanent magnetic fields, electromagnetic fields, or tracked magnetic fields; the permanent magnetic field or electromagnetic field is cylindrical, horseshoe-shaped, uniform magnetic field, motor-driven spherical cap magnetic field, or vertically superimposed magnetic field; the tracked magnetic field is a rubber magnetic track or a track with a magnetic plate clamped on it.

[0031] The light field is a variable light field, composed of a parallel light source 3 and a variable aperture. The parallel light source 3 includes a light source and a parallel light lens. The light source is a UV light source or an EB electron beam, and the corresponding inducible ink is a UV-curable ink or an electron beam-curable ink. The light from the parallel light source 3 is projected onto the surface of the printing substrate 1 through the variable aperture. The variable aperture is formed by a transparent film 4, a film transmission system 5, and a fixed inkjet system 6 and an inkjet drying unit 7. The film transmission system 5 drives the transparent film 4 and the printing substrate 1 at the same linear speed. The inkjet system 6 and the inkjet drying unit 7 work continuously, continuously outputting a variable aperture pattern to the surface of the driven transparent film 4. The light emitted from the parallel light source 3 passes through the transparent film 4 with the existing aperture pattern and is projected onto the surface of the printing substrate 1, so that the aperture pattern is transferred into the ink coating on the surface of the printing substrate 1.

[0032] At this point, several options are available depending on the design:

[0033] The induced ink pattern, after a partial exposure, is then partially exposed again through a second imaging optical-magnetic dual field designed with the same principle as the aforementioned optical-magnetic dual field. Theoretically, it can enter the imaging optical-magnetic dual field multiple times and be partially exposed multiple times. Considering the complexity of the process, one or two partial exposures are generally sufficient to achieve complex patterns.

[0034] After final magnetic field and light curing, the induced ink pattern is sequentially transmitted out of the last imaging optical-magnetic dual field. The exposed part has been cured, but the pigment arrangement of the uncured part and the cured part is the same. Therefore, it is necessary to use another magnetic field to change the pigment arrangement of the uncured part. Thus, the pigment flakes of the uncured part are induced again by the curing magnetic field and then enter the irradiation area of ​​the curing light field for final curing.

[0035] In fact, the methods for preparing the aforementioned variable aperture film include the following:

[0036] 1. Thermosensitive and Thermal Transfer Technology for Preparing Variable Aperture Film: This technology requires a high-temperature color-developing thermosensitive film. This film remains unchanged at room temperature, but as the temperature rises, a chemical reaction occurs, changing the color from transparent to black. This reaction occurs at temperatures above 200°C and is completed within tens of microseconds. The basic principle of thermal transfer technology is similar to that of thermosensitive technology; it consists of a thermal transfer ribbon and a transparent substrate film. The thermal head sequentially contacts the thermal transfer ribbon and the transparent substrate film, transferring and melting the coloring material from the thermal transfer ribbon onto the transparent substrate film to form a pattern.

[0037] 2. Inkjet printing for variable aperture film: Using piezoelectric inkjet technology, the nozzles print variable patterns online on a transparent film;

[0038] 3. Dot matrix and laser printing for creating variable aperture film: Using existing dot matrix and laser printers, variable patterns are printed online on transparent film.

[0039] Example 2:

[0040] This embodiment is similar to Embodiment 1, the only difference being the difference in the optical field within the imaging optical-magnetic dual field, as detailed below. Figure 2 As shown, the light field is a fixed aperture, which consists of a transparent film 40 with a pre-formed continuous pattern and a parallel light source 30. The transparent film 40 is transported at the same linear speed as the printing substrate. When the transparent film 40 is transported between the parallel light source 30 and the printing substrate, the light emitted from the parallel light source 30 is projected onto the ink coating on the surface of the printing substrate through the transparent film 40, thereby transferring the pattern into the ink coating.

[0041] The transparent film 40 can be prepared into a closed loop for continuous recycling.

[0042] After the printing substrate is conveyed into the region that can be induced by the synchronous magnetic field, the pigment flakes in the ink pattern are oriented under the induction of the magnetic field. Since the printing substrate of the induced ink pattern and the synchronous magnetic field are relatively stationary, the printing substrate of the induced ink pattern and the synchronous magnetic field enter the region below the light field synchronously. At this time, the transparent film 40 is also synchronously driven and continuously outputs the pre-prepared light barrier pattern. After the parallel light source 30 passes through the light barrier pattern, it exposes and cures the light barrier pattern on the induced ink pattern. After exposure through the light barrier pattern, the induced ink pattern is sequentially conveyed out of the light field and the synchronous magnetic field.

[0043] Example 3:

[0044] This embodiment is similar to Embodiment 2, the only difference being the difference in the optical field within the imaging optical-magnetic dual field, as detailed below. Figure 3 As shown, the light field consists of a parallel light source 300 and a fixed aperture. The fixed aperture is formed by a transparent film 400 with a continuous pre-formed pattern that circulates at the same linear velocity as the printing substrate and a fixed light-shielding body 500. The light-shielding body 500 has a light-transmitting slit. The transparent film 400 moves through the light-shielding body 500. The parallel light source 300 is positioned above the light-shielding body 500 and sequentially projects through the transparent film 500 and the light-transmitting slit onto the ink coating of the printing substrate, transferring the pre-formed pattern portion exposed on the transparent film 400 by the light-transmitting slit of the light-shielding body into the ink coating on the surface of the printing substrate.

[0045] Example 4:

[0046] This embodiment is similar to Embodiment 2, except that the light field in the imaging optical-magnetic dual field is different. The light field adopts a pulsed projection aperture, which includes a parallel light source and a pre-patterned pulsed transmission transparent film. The parallel light source is set above the transparent film. Each pulse transmission of the transparent film causes one or a group of patterns on it to be located between the parallel light source and the printing substrate. The emitted light from the parallel light source is projected onto the ink coating on the surface of the printing substrate through the pattern of the transparent film, thereby transferring the pattern into the ink coating.

[0047] Example 5:

[0048] This embodiment is similar to any of embodiments one through four, the only difference being the setting of the solidification magnetic field, as detailed below. Figure 4As shown, one pole of the curing magnetic field 90 is positioned above the printing substrate 100, and the other pole is positioned below the printing substrate 100. Moreover, the one pole and the other pole of the curing magnetic field 90 are perpendicular and symmetrical with respect to the surface of the printing substrate 100, or are inclined with respect to the surface of the printing substrate, such that the line connecting the two poles is not perpendicular to the printing substrate and forms an angle. If the angle is well controlled, a side-coded invisible effect can be formed.

[0049] Example 6:

[0050] The security pattern prepared by the system in this embodiment is a QR code or a variable code, and the magnetic field of the imaging optical-magnetic dual field is as follows: Figure 5 The fixed planar magnetic field shown is used to induce an induced ink coating on the printing substrate, with the pigment flakes in the corresponding ink coating arranged in a planar manner. The light field is used to solidify the portion of the ink coating induced by the magnetic field that is irradiated by the light field.

[0051] Since QR codes and variable codes require a sufficiently smooth surface for the ink coating, the imaging optical-magnetic dual field adopts the method described in this embodiment, and the magnetic field for solidifying the optical-magnetic dual field can be selected from one of the two methods in Embodiment 1 and Embodiment 5.

[0052] It should be noted that, except for Example 5, the magnetic fields of the curing magnetic field and the imaging optical-magnetic dual field in the other examples are all set below the printing substrate, so the N and S poles of the two magnetic fields should be set up oppositely.

Claims

1. A system for preparing a security pattern, characterized in that, It includes: A printed substrate with an inducible ink coating printed on its surface, and at least one imaging optical-magnetic dual field and one curing optical-magnetic dual field for forming a variable security pattern on the surface of the printed substrate; the printed substrate is conveyed and sequentially passes through the at least one imaging optical-magnetic dual field and the curing optical-magnetic dual field; the imaging optical-magnetic dual field system includes an optical field and a magnetic field, the optical field and the magnetic field being respectively positioned above and below the printed substrate, the magnetic field being used to induce the inducible ink coating on the printed substrate to form a magnetic field pattern, and the optical field using a transparent film as a pattern carrier to cure the portion of the ink coating induced by the magnetic field corresponding to the pattern; The curing photomagnetic dual field includes a curing light source and a curing magnetic field. The curing light source and the curing magnetic field are respectively disposed above and below the printing substrate. Alternatively, one pole of the curing magnetic field is disposed above the printing substrate and the other pole is disposed below the printing substrate, so that the curing magnetic field can re-induce the portion of the ink coating that has not been irradiated by the light field. The curing light source is used to cure the re-induced ink coating. The light field includes a parallel light source and a fixed aperture. The fixed aperture is formed by a transparent film with a continuous pre-made pattern that circulates at the same linear velocity as the printing substrate and a fixed light-shielding body. The light-shielding body has a light-transmitting slit. The transparent film moves through the light-shielding body. The parallel light source is positioned above the light-shielding body and sequentially projects through the transparent film and the light-transmitting slit onto the ink coating of the printing substrate, transferring the pre-made pattern portion exposed on the transparent film by the light-transmitting slit of the light-shielding body into the ink coating on the surface of the printing substrate. The light transmittance of the transparent film is 70-100%; The parallel light source includes a light source and a parallel light lens.

2. The system according to claim 1, characterized in that: The first and second poles of the curing magnetic field are perpendicularly symmetrical with respect to the surface of the printing substrate, or are inclined with respect to the surface of the printing substrate.

3. The system according to claim 2, characterized in that: The inducible ink is a UV-curable ink or an electron beam-curable ink.

4. The system according to claim 3, characterized in that: The magnetic field and / or solidified magnetic field is a permanent magnetic field, an electromagnetic field, or a tracked magnetic field; the permanent magnetic field or electromagnetic field is cylindrical, horseshoe-shaped, planar magnetic field, uniform magnetic field, motor-driven spherical cap magnetic field, or vertically superimposed magnetic field; the tracked magnetic field is a rubber magnetic track or a track with a magnetic plate clamped on it.

5. The system according to claim 4, characterized in that, The security pattern is a QR code and a variable code; the magnetic field is a fixed planar magnetic field, and the magnetic field distribution is the same in a certain area of ​​the moving direction; the magnetic field is used to induce the induced ink coating of the printing substrate, and the pigment flakes in the corresponding ink coating are arranged in a plane; the light field is used to cure the part of the ink coating induced by the magnetic field that is irradiated by the light field.

6. The system according to claim 5, characterized in that, The magnetic field moves synchronously with the printed substrate.

7. The system according to claim 1, characterized in that, The light source is either a UV light source or an EB electron beam.

8. The system according to claim 1, characterized in that, When both the magnetic field and the curing magnetic field are positioned below the printed substrate, the poles of the magnetic field and the curing magnetic field are in opposite directions.

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