JP4198411B2 - Recording sheet for laser marking and method of using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a recording sheet for laser marking and a method for using the same, and more particularly to a recording sheet for laser marking used for preventing falsification of recorded contents by additional writing and a method for using the same.
[0002]
[Prior art]
The recording sheet on which the surface is printed is irradiated with laser light, and the ink layer at the irradiated portion is removed to expose the surface of the underlying substrate to the surface of the recording sheet. A laser marking method that displays characters, symbols, and the like using a difference in hue from printing is known (for example, Japanese Patent Application Laid-Open No. 11-70734).
[0003]
The feature of printing by the laser marking method as described above is that the printing and the recording sheet are inseparable, and it is difficult to erase only the printing without affecting the periphery of the printing. In other words, if you want to erase the print, there are methods such as removing the ink layer around the print to obscure the contents of the print or erasing the characters by printing on the print with the same color ink as the solid print. Although it is conceivable, in any of the methods, since some traces associated with the erasure of printing remain on the surface of the sheet base material, it is easily discriminable if the printing is erased by such a method. For this reason, recording sheets for preventing counterfeiting and tampering using such a sheet base material have been studied.
[0004]
[Problems to be solved by the invention]
However, if the recording sheet is simply provided with a single layer of solid printing on the surface as described above, additional writing can be freely made on the solid printing surface. Forgery and falsification due to the addition of this could not be dealt with sufficiently. Therefore, in order to use the recording sheet as described above for the purpose of preventing forgery or falsification, measures against such additional writing are indispensable.
From the above, there has been a demand for a recording sheet for laser marking that can be applied not only to erasure of printing but also forgery and alteration by additional writing and applicable to important documents such as securities.
[0005]
The present invention has been made in view of such a situation. That is, the present invention does not provide an appropriate print even if additional recording is performed on a printed laser marking recording sheet. It is an object of the present invention to provide a recording sheet for laser marking and a method for using the same so that it can be easily discriminated.
[0006]
[Means for Solving the Problems]
That is, according to the first aspect of the present invention, there is provided a recording sheet for laser marking that irradiates a laser beam to form a print of characters, symbols, pictures, etc. on a print surface, and at least a part of the sheet base material is overlapped with each other. In the multilayer recording layer in which the color-coded recording layers are stacked on at least one side of the sheet base material so that the same color does not overlap with each other, the recording layer of the multilayer has the same pattern and different color recording layers. A recording sheet for laser marking, comprising: a set, and a coating layer that covers the surface of the multilayer recording layer and serves as the printing surface.
[0011]
The invention according to claim 2 is a multilayer recording layer in which a sheet base material and a recording layer color-coded so that at least a part of the same color does not overlap with each other when stacked on each other are laminated on at least one side of the sheet base material. The multi-layer recording layer includes a set of recording layers of the same pattern and different colors, and a covering layer that covers the surface of the multi-layer recording layer and serves as a printing surface. A method of using a laser beam to selectively expose the color-coded recording layer of a predetermined color from a plurality of recording layers provided at a printing position, such as characters, symbols, pictures, etc. A method of using a recording sheet for laser marking, characterized by forming a print.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Next, a laser marking recording sheet according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is an exploded perspective view showing the structure of a recording sheet for laser marking (hereinafter referred to as a recording sheet) 1, FIG. 2 is a transverse cross-sectional view thereof, and FIG. FIG. 4 is a perspective view showing the formed state, FIG. 4 is a plan view when the laser irradiation is performed so that the black ink layers 21 and 31 are exposed by the method of the present invention, FIG. FIG. 7 is a cross-sectional view taken along the line Y-Y of FIG. 7, and FIG. 8 is a case where laser irradiation is performed with energy that partly reaches the surface of the second recording layer. FIG. 9 is a sectional view taken along the line ZZ.
[0013]
As shown in FIGS. 1 and 2, the recording sheet 1 of the present invention is obtained by sequentially printing the second recording layer 30, the first recording layer 20, and the coating layer 10 on the surface of the sheet substrate 60 and printing them with printing ink. It is. As the sheet base material 60, a paper base material used in a printer or printing is used. In addition, a base material composed of one or a plurality of materials including a plastic film, a metal foil, or the like is used. Used. The second recording layer 30 is composed of a black ink layer 31 and a white ink layer 32 which are exposed on the surface to form characters, symbols, and the like, and these are at least large enough to cover the print width. Are provided on the surface of the sheet base material 60 alternately and in parallel. In addition, the first recording layer 20 is printed on the surface of the second recording layer 30, but the first recording layer 20 has the same pattern as the second recording layer 30 and has a different black and white color. A white ink layer 22 is overlaid on the black ink layer 31, and a black ink layer 21 is overlaid on the white ink layer 32. The first recording layer 20 is provided with a color density and thickness sufficient to conceal the second recording layer 30 so that the configuration of the second recording layer 30 cannot be seen. Further, a coating layer 10 is printed on the surface of the first recording layer 20 with white ink. The coating layer 10 also conceals the first recording layer 20 so that the configuration of the first recording layer 20 cannot be seen. And a sufficient color density and thickness. The covering layer 10 is preferably provided so as to cover the first recording layer 20 entirely, but the printing shape of the black ink layer 21 and the white ink layer 22 of the first recording layer 20 and the position between them cannot be specified. If formed in this way, the first recording layer 20 does not necessarily have to be entirely covered.
[0014]
As shown in FIG. 3, the recording sheet 1 having the above-described configuration is a roll that can be applied by applying the adhesive 2 to the non-printing surface on the back surface, and temporarily attaching the adhesive 2 to the release mount 3 via the adhesive 2. You may wind around the core core 4 in a state. In this figure, a printing pitch detection mark 5 that determines the printing position of the laser marking device and a symbol 6 such as a bar code or a two-dimensional code in which various information necessary for printing is input are printed on the back surface of the peeling mount 3. However, these printing pitch detection marks 5 and symbols 6 may be formed on the printing surface or non-printing surface of the recording sheet 1 as long as they are visible from the outside. If the sheet base 30 is an RFID card, the information can be recorded on an IC chip.
[0015]
Here, various information necessary for printing includes the printing start position and end position, the positions of the black ink layers 21, 31 and the white ink layers 22, 32, the printing thickness, material, and energy required for removal. And the type of laser marking device that performs printing. If various types of information necessary for printing are added to the recording sheet 1 as described above, printing can be performed without erroneous laser irradiation conditions when performing laser irradiation based on the method described later. It is. In addition, after printing, various information necessary for printing is erased from the recording sheet 1 by, for example, detaching it together with the peeling mount 3 or deleting it by laser irradiation. Since there are no clues, counterfeiting and tampering become more difficult.
[0016]
Next, a method of using the recording sheet 1 having the above configuration will be described.
First, the recording sheet 1 is attached to a paper attachment device of a laser marking device (not shown). The laser marking device used here can control the irradiation energy and spot diameter of the laser beam, and the irradiation head precisely moves the irradiation surface by a paper transport device, an irradiation head drive device, etc. It is possible to do.
[0017]
Next, a method for forming a print by irradiating the recording sheet 1 with a laser will be described in detail. In the present embodiment, for the five-digit number “12345”, the numbers “1”, “3”, and “5” are printed on the coating layer 10 in contact with the white ink layer 22 and “2”, The case where each number of “4” is printed on the coating layer 10 in contact with the black ink layer 21 is illustrated. Here, the irradiation energy required for printing differs depending on the laser irradiation position of the recording sheet 1. That is, when the laser irradiation position is above the coating layer 10 in contact with the white ink layer 22, both the coating layer 10 and the white ink layer 22 can be removed and do not reach the sheet base material layer 60. Printing is performed by irradiating the laser beam with the adjusted irradiation energy. On the other hand, when the laser irradiation position is above the coating layer 10 in contact with the black ink layer 21, the laser with irradiation energy adjusted so that the coating layer 10 can be removed and does not reach the second recording layer 30. Printing is performed by irradiating light. In this way, the recording layers colored in black from the multiple recording layers provided at the printing position are selectively exposed. The results are as shown in FIGS. 4 and 5, and the print recording sheet 100 in which the black ink layers 21 and 31 are exposed on the surface of the recording sheet 1 and “12345” is displayed in black is obtained. The above printing is performed by extracting various information such as the position information of the white ink layers 22 and 32 and the black ink layers 21 and 31 necessary for printing from the base sheet 1 and inputting them to the laser irradiation apparatus. To be achieved.
[0018]
On the other hand, a case will be described in which printing is performed on the recording sheet 1 with a certain level of irradiation energy as usual without having such information. 6 and 7 show a case where a five-digit number “12345” is irradiated from the top of the coating layer 10 of the recording sheet 1 with a certain level of irradiation energy capable of removing only the coating layer 10. . That is, the coating layer 10 of the recording sheet 1 is removed by the laser beam, and the print recording sheet 200 in which the black ink layer 21 and the white ink layer 22 of the first recording layer 20 are exposed is obtained. In this case, the printed portions of “1”, “3”, and “5” above the white ink layer 22 exhibit the same white color as that of the covering layer 10, so a black and clear print is formed although a slight concave portion of the print is formed. It will not be. On the other hand, “2” and “4” above the black ink layer 21 are black and clearly printed due to the exposure of the black ink layer 21. If additional writing is performed in such a state, it is obvious that the additional writing is made only by looking at the print.
[0019]
Next, a case where printing is performed with a certain irradiation energy stronger than the above will be described. In this case, the removal of the first recording layer 20 in addition to the coating layer 10 also proceeds. In general, different materials used for the recording sheet 1 have different energy absorption capabilities, and the depth of the ink layer to be removed varies depending on the material even when laser light having a constant energy is irradiated. Usually, the black ink layers 21 and 31 contain a black pigment such as carbon black, and the white ink layers 22 and 32 contain a white pigment such as titanium oxide. The black ink layer emits laser light. Since it is easy to absorb, deeper prints can be achieved with the same irradiation energy. FIG. 8 and FIG. 9 show a case where a five-digit number “12345” is printed with a constant irradiation energy having the strength to completely remove the black ink layer 21 at the positions “2” and “4”. It is a thing. In this case, printing of “1”, “3”, and “5” only removes the white ink layer 22 partway, so that the printing depth is deeper than that of the print recording sheet 100, but a clear black print is obtained. Absent. In the case of “2” and “4”, since the black ink layer 21 is completely removed, the underlying white ink layer 32 is exposed, and this also makes it impossible to obtain black and clear printing. However, in this case, as schematically shown in the print recording sheet 300 of FIG. 8, if the angle is changed, the print periphery is bordered by the black ink layer 21. In any case, it is not possible to obtain a predetermined print, and it is obvious at a glance that the information has been added.
[0020]
Even when irradiation energy stronger than the above is given and the white ink layer 22 under the printing of “1”, “3”, “5” is completely removed, a predetermined printing cannot be obtained (not shown). . In this case, the black ink layer 31 under “1”, “3”, and “5” is exposed, and the prints of “1”, “3”, and “5” are displayed in black. On the other hand, the white ink layer 32 under the printing of “2” and “4” is further removed than in the case of FIG. 9 and the printing becomes deeper, but when viewed from the surface of the recording sheet 1, the white ink layer 32. Is exposed, and black and clear printing cannot be obtained. It is obvious that this was also added.
[0021]
As described above, it is obvious that proper printing cannot be obtained by printing on the recording sheet 1 with laser light having a constant irradiation energy.
[0022]
FIG. 10 shows the second embodiment of the recording sheet for laser marking according to the present invention. However, the same parts as those in FIGS. 1 to 9 are denoted by the same reference numerals, and detailed description thereof will be omitted. In the recording sheet 400 of the present embodiment, the reflective layer 50 and the third recording layer 40 are sequentially laminated between the base sheet 60 and the second recording layer 30 as viewed from the base sheet 60. Here, each recording layer is provided with black ink layers 21, 31, 41, white ink layers 22, 32, 42, and red ink layers 23, 33, 43 in different colors. The reflective layer 50 is provided so that the substrate sheet 60 is not damaged by laser irradiation, and is printed by making mica, aluminum, silicon dioxide, titanium oxide or the like into ink. When black printing is performed at the position of the black ink layer 21 using the recording sheet 400, the coating layer 10 can be removed and irradiation with laser light having irradiation energy adjusted so as not to reach the second recording layer 30 is performed. This is achieved by printing. As described above in detail, black printing and red printing at other positions can be achieved by printing in the same manner. When the number of colors is further required, at least the number of colors may be provided between the covering layer and the sheet base material as the recording layer color-coded with a desired color. It is also possible to change the white ink layer to a desired color.
[0023]
The present invention is not limited to the embodiment described above, and various modifications and changes can be made. For example, the coating layer 10 and the recording layers 20, 30, and 40 are not limited to printing inks, and thermal transfer ink (thermal transfer system), toner (electrophotographic system), inkjet ink (inkjet system), paint (painting system), and the like can be used. It is. In addition, it may be formed by extrusion molding of a plastic such as PE (polyethylene), PP (polypropylene), PET (polyester), PVC (vinyl chloride), or bonding of films. Needless to say, the color-coded patterns and colors of the recording layer are not limited to the above example, and a desired pattern such as a company name logo can be formed in a desired color. If the pattern is changed for each product and each manufacturing time, it is more suitable for preventing forgery and tampering. Further, if necessary, a material having a high laser light absorption ability or a material having a high concealment property may be appropriately combined with the binder of each layer, and a difference in the energy absorption ability of the laser light may be appropriately provided.
[0024]
【The invention's effect】
As described above, according to the recording sheet for laser marking according to the present invention, since the desired printing cannot be performed unless the printing energy is changed according to the color-coded pattern of the recording layer, forgery and tampering due to additional writing are prevented. it can. Further, if additional writing is performed, a trace of printing remains on the recording sheet for laser marking, so that it can be easily determined that additional writing of printing has been attempted by checking the printing surface. Further, since the recording layer can be color-coded by a desired color, a desired color printing can be performed. Furthermore, according to the printing method of the present invention, since it is possible to perform suitable printing on a laser marking recording sheet that can be easily discriminated, it is possible to provide a printing method that has an excellent effect of preventing falsification and forgery. It becomes.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view showing a configuration of a laser marking recording sheet (recording sheet) 1 according to a first embodiment of the present invention.
FIG. 2 is a cross-sectional view thereof.
FIG. 3 is a perspective view showing a state in which the adhesive is processed and temporarily attached to the release mount 3 to form a roll.
FIG. 4 is a plan view when laser irradiation is performed so that black inks 21 and 31 are exposed by the method of the present invention.
FIG. 5 is a sectional view taken along line XX.
FIG. 6 is a plan view when laser irradiation is performed with energy capable of removing the coating layer 10;
FIG. 7 is a YY cross-sectional view thereof.
8 is a plan view in the case where laser irradiation is performed with energy partially reaching the surface of the second recording layer 31. FIG.
FIG. 9 is a ZZ cross-sectional view thereof.
FIG. 10 is an exploded perspective view showing a configuration of a recording sheet for laser marking 400 according to a second embodiment of the present invention.
[Explanation of symbols]
1,400 Laser marking recording sheet (recording sheet)
2 Adhesive 3 Release mount 4 Core core 5 Print pitch detection mark 6 Symbol such as bar code or two-dimensional code 10 Cover layer 20 First recording layer 21, 31, 41 Black ink layer 22, 32, 42 White ink layer 30 First 2 recording layer 40 3rd recording layer 50 reflective layer 60 sheet base material 100, 200, 300 printing recording sheet

Claims (2)

In the recording sheet for laser marking that forms characters, symbols, pictures, etc. on the printing surface by irradiating the laser beam,
A sheet base material, and a multi-layer recording layer in which at least a part of the same color is overlapped with each other so that the same color layers do not overlap each other when laminated on at least one side of the sheet base material;
The multilayer recording layer includes a set of the recording layers of the same pattern and different colors,
A recording sheet for laser marking, comprising: a coating layer that covers the surface of the multilayer recording layer and serves as the printing surface. A sheet base material, and a multi-layer recording layer in which at least a part of the same color is overlapped with each other so that the same color layers do not overlap each other when laminated on at least one side of the sheet base material;
The multilayer recording layer includes a set of the recording layers of the same pattern and different colors,
A method of using a recording sheet for laser marking comprising a coating layer that covers the surface of the multi-layer recording layer and serves as a printing surface,
Irradiating laser light to selectively expose the color-coded recording layer of a predetermined color from a plurality of recording layers provided at a printing position, thereby forming printing of characters, symbols, pictures, etc. And a method of using a recording sheet for laser marking.

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