JPH06234289A - Latent image forming member - Google Patents

Abstract

PURPOSE:To obtain a latent image forming member ensuring the hiding of the presence of a printing layer having a latent image pattern. CONSTITUTION:In a latent image forming member comprising a substrate 1, a printing layer provided on the substrate 1 with a latent image pattern 2 containing a phosphor excited by an infrared radiation, and a hiding layer 4 provided on the printing layer and composed of infrared radiation-transmitting ink for hiding the printing layer, the hiding layer 4 is composed of the ink of two or more colors.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a latent image forming member such as a credit card or a prepaid card provided with a means for preventing forgery, alteration, tampering, etc., and in particular, it is known that a printing layer having a latent image pattern is present. The present invention relates to a latent image forming member which is not provided.

[0002]

2. Description of the Related Art In recent years, credit cards and prepaid cards have been used as a payment method in place of cash. These cards are provided with anti-counterfeiting means, or it is determined whether or not the cards are counterfeit. Various methods have been proposed.

FIG. 9 is an enlarged sectional view for explaining the card described in Japanese Patent Laid-Open No. 3-258592.

As shown in FIG. 1, on the surface of the card substrate 100, there is formed a printing layer 101 having a bar code pattern printed with an infrared-exciting ink (phosphor) that absorbs infrared rays and emits fluorescence. There is.

The printing layer 101 is covered with a concealing layer 102 which transmits infrared rays and absorbs a part of visible light, so that the printing layer 101 cannot be seen directly from the card surface.

[0006]

Since the printing layer 101 is covered with the concealing layer 102, it cannot be seen directly from the surface of the card. However, as shown in FIG. 9, the printing layer 1 is actually visible.
Unevenness is formed on the surface of the hiding layer 102 where 01 (bar code pattern) exists and where it does not. Therefore, especially the hiding layer 10
When 2 is a solid color of 1 color, the printing layer 101 is
The existence of the (bar code pattern) can be clearly discriminated, and the effect of providing the concealing layer 102 cannot be sufficiently exerted.

An object of the present invention is to solve the above-mentioned drawbacks of the prior art and to provide a latent image forming member capable of surely not knowing the existence of a printing layer having a latent image pattern.

[0008]

In order to achieve the above object, the present invention provides a substrate, a printing layer of a latent image pattern including a phosphor excited by infrared rays above the substrate, and the printing layer. A latent image forming member having an infrared transmissive ink above and a hiding layer for hiding the printing layer, wherein the hiding layer is composed of two or more colors of ink. .

[0009]

As described above, according to the present invention, since the hiding layer is composed of inks of two or more colors, even if unevenness is formed on the surface of the hiding layer due to the presence of the printing layer, the printing layer can be visually recognized. It becomes impossible to recognize the existence of, and the concealment effect is certain.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view of a card according to this embodiment before forming a hiding layer, FIG. 2 is an enlarged cross-sectional view of an essential part of the card before forming a hiding layer, and FIG. 3 is a view of forming a hiding layer of the card. Later plan view, and FIG. 4 is an enlarged cross-sectional view of a main part of the card after the concealing layer is formed.

As shown in FIG. 1, a printed layer 3 having a latent image barcode pattern 2 is formed on the surface of a card substrate 1. The card substrate 1 is composed of, for example, a vinyl chloride-based sheet in which a white pigment such as titanium oxide is dispersed and held, and has a property of reflecting infrared light and visible light.

The printing layer 3 is an ink composed of fluorescent fine particles that are excited by irradiation of infrared rays (including near infrared rays) and a transparent binder that disperses and holds the fine particles, that is, absorbs infrared rays to generate fluorescence. Infrared excitation ink (phosphor ink) that emits the desired barcode pattern 2
Is printed.

The phosphor fine particles are, for example, NdP.
₅ O ₁₄ , LiNdP ₄ O ₁₂ , Al ₃ Nd (BO ₃ ) ₄
An inorganic compound selected from the group of, or an inorganic compound represented by the following general formula.

General formula Ln _1-XY Nd _X Yb _Y Z Ln in the formula is Bi, Ge, Ga, Gd, In, La,
Represents one or more elements selected from the group of Lu, Sb, Sc and Y.

In the formula, Z is A ₅ (MO ₄ ) ₄ A is at least one element selected from the group of K and Na, and M is at least one element selected from the group of W and Mo. Represent

D ₃ (BO ₃ ) ₄ D represents at least one element selected from the group consisting of Al and Cr.

P ₅ O ₁₄ A ₃ (PO ₄ ) ₂ A represents one or more elements selected from the group of K and Na.

Na ₂ Mg ₂ (VO ₄ ) ₃ A '(MO ₄ ) ₂ A'is one or more elements selected from the group of Li, K and Na, and M is selected from the group of W and Mo. Represents one or more elements.

In the formulas x and y, Z is A ₅ (M
O ₄ ) ₄ is a numerical value in the range of 0.25 ≦ x ≦ 0.99 and 0.01 ≦ y ≦ 0.75, and Z is D ₃ (BO
₃ ) ₄ when 0.10 ≦ x ≦ 0.99 and 0.
Numerical value in the range of 01 ≦ y ≦ 0.90, when Z is P ₅ O ₁₄ , 0.05 ≦ x ≦ 0.98 and 0.02 ≦ y ≦
When the numerical value in the range of 0.95 and Z is A ₃ (PO ₄ ) ₂ , 0.02 ≦ x ≦ 0.98 and 0.02 ≦ y ≦ 0.
When the numerical value in the range of 98, Z is Na ₂ Mg ₂ (VO ₄ ) ₃ , 0.57 ≦ x ≦ 0.90 and 0.10 ≦ y ≦
When the numerical value in the range of 0.43, Z is A ′ (MO ₄ ) ₂ , 0.20 ≦ x ≦ 0.95 and 0.05 ≦ y ≦ 0.
It is a numerical value in the range of 80.

Specifically, for example, the following can be used.

Nd _0.8 Yb _0.2 Na ₅ (WO ₄ ) ₄ , N
d _0.9 Yb _0.1 Na ₅ (Mo ₄ ) ₄ , Y _0.1 Nd _0.75
Yb _0.15 (WO ₄ ) ₄ , Nd _0.8 Yb _0.2 Na ₅ (Mo
_0.5 W _0.5 O ₄ ) ₄ , Bi _0.1 Nd _0.75 Yb _0.15 K ₅
(MoO ₄ ) ₄ , La _0.1 Nd _0.8 Yb _0.1 (Na _0.9
K _0.1 ) ₅ (WO ₄ ) ₄ , Nd _0.9 Yb _0.1 Al ₃ (B
O ₃ ) ₄ .

Further, an inorganic compound represented by the following general formula can be used.

General formula EF _1-XY Nd _X Yb _Y P ₄ O ₁₂ E in the formula is one or more elements selected from the group of Li, Na, K, Rb and Cs, and F in the formula is Sc, Y, L
Represents one or more elements selected from the group consisting of a, Ce, Gd, Lu, Ga, In, Bi and Sb.

X and y in the formula are numerical values within the following ranges.

0.05 ≤ x ≤ 0.999 0.001 ≤ y ≤ 0.950 x + y ≤ 1.0 Specifically, for example, the following can be used.

LiNd _0.9 Yb _0.1 P ₄ O ₁₂ , LiB
i _0.2 Nd _0.7 Yb _0.1 P ₄ O ₁₂ , NaNd _0.9 Yb
_0.1 P ₄ O ₁₂ .

Thus, the phosphor to which neodymium (Nd) is added as an activator is chemically stable and has a high excitation efficiency, and thus can be used for a prize.

As the binder, for example, wax, vinyl chloride-vinyl acetate copolymer, ethylene-vinyl acetate copolymer, polyester, polyurethane, carbonate or the like may be used alone or as a mixture. In addition,
If necessary, a plasticizer, a surfactant and the like are added appropriately.

The content of the fluorescent fine particles in the bar code pattern 2 is suitably 50 to 80% by weight, and in this embodiment it is 75% by weight. When the content of the fluorescent fine particles is less than 50% by weight, the output from the barcode pattern 2 is weak, while when the content of the fluorescent fine particles exceeds 80% by weight, the printability of the barcode pattern 2 is deteriorated. There is a risk of printing defects.

When infrared rays having a central wavelength matching the excitation wavelength of the phosphor to be used are irradiated toward the bar code pattern 2, the phosphor fine particles receive the infrared light and are excited to emit light. In order to effectively perform the excitation, the light reflectance of the card base material 1 is set to 20% or more. That is, by making the card substrate 1 have a high reflectance, infrared rays are reflected on the surface of the card substrate 1,
It promotes the excitation of phosphor fine particles. As described above, the reflectance of the card substrate 1 can be increased by adding the white pigment to the card substrate 1. In the case of the present embodiment, the card substrate 1 having the reflectance of 80% is used. There is. If the reflectance is less than 20%, the phosphor fine particles are not efficiently excited, and therefore the emission output of the barcode pattern 2 is small relative to the input energy of infrared rays.

In the following table, the vertical direction containing the white pigment is 5.5.
In the case where the bar code pattern 2 having a thickness of 4 μm is formed on the surface of the card substrate 1 having a size of cm, a width of 8.5 cm and a thickness of 188 μm, the content of the white pigment is adjusted to reflect the card substrate 1. It is a table which shows the result of having measured the output voltage and S / N of the bar code pattern 2 when changing the ratio variously.

The measuring device used for this was an infrared light emitting diode TLN201 (infrared light emitting diode made of GaAlAs, center wavelength 880 nm) manufactured by Toshiba Corporation, and infrared light from the light emitting diode was passed through an optical fiber (diameter 1 mm). The bar code pattern 2 was irradiated vertically. Then, the excitation light from the barcode pattern 2 is transmitted through the optical fiber (1.2 mm in diameter) to I
A photodiode TPS703 (light receiving element made of silicon) manufactured by Toshiba Corp. is configured to receive light through a filter made of nP.

Table Base material reflectance (%) Output voltage (mV) S / N 2 23 1.10 5 36 1.25 20 61 61 1.61 30 77 1.73 50 50 120 2.51 60 130 2.93 80 580 3.60 As is apparent from this table, when the reflectance of the base material is less than 20%, the output voltage cannot be sufficiently obtained, and the S / N is small, so that accurate information cannot be read. On the other hand, the reflectance of the substrate is 20% or more, preferably 50%
As described above, more preferably 80% or more, the output voltage and S / N are high, and accurate information can be read.

FIG. 5 is a characteristic diagram showing the relationship between the film thickness of the bar code pattern 2 (printing layer 3) and the output voltage. The horizontal axis represents the thickness of the bar code pattern 2 (printing layer 3), and the vertical axis represents the thickness. Output voltages by excitation of the bar code pattern 2 (printing layer 3) are shown in FIG.

The curve A in the figure is the barcode pattern 2 (printing layer 3) on the surface of the substrate containing the white pigment as described above.
Characteristic curve showing the relationship between the thickness of the bar code pattern 2 (printing layer 3) and the output voltage, the straight line B indicates that the output of the bar code pattern 2 (printing layer 3) is a group containing the white pigment. Material (80% average light reflectance in the visible light range)
It is a straight line showing an output level that is 1.6 times the output voltage of only

As a result of various experiments conducted by the present inventors, when the output voltage of the bar code pattern 2 (printing layer 3) is smaller than 1.6 times the output voltage of only the base material, the bar code pattern 2 (printing layer 3). Since it is not possible to sufficiently read the bar code according to the above, the output voltage of the bar code pattern 2 (printing layer 3) needs to be 1.6 times or more the output voltage of the base material only. The minimum thickness of layer 3) is 0.5 μm, as is apparent from this figure. The output voltage increases as the thickness of the bar code pattern 2 (printing layer 3) increases, but becomes almost constant when the thickness of the bar code pattern 2 (printing layer 3) reaches about 50 μm. The thickness of the bar code pattern 2 (printing layer 3) is 20 μm.
When it exceeds m, the barcode pattern 2 (printing layer 3) is formed even if a concealing layer composed of two or more colors of ink as described below is formed.
Since it is easy to visually confirm the presence of the, the thickness of the barcode pattern 2 (printing layer 3) should be regulated within the range of 0.5 to 20 μm.

As shown in FIGS. 3 and 4, the bar code pattern 2 (printing layer 3) is formed on the entire surface of the card substrate 1.
The hiding layer 4 is formed so as to cover the. This hiding layer 4
In the example, a large number of irregular small patterns 5 each having a psychedelic pattern are formed with multicolor inks of two or more colors. In the case of this embodiment, as shown in FIG. 4, the concealing layer 4 is composed of one layer and is formed by a substantially continuous layer of ink layers 6a and 6b of different colors (see FIG. 3).

FIGS. 6 and 7 are views showing modified examples of the hiding layer 4, and in this case also, the hiding layer 4 is formed on the entire surface of the card substrate 1 so as to cover the bar code pattern 2 (printing layer 3). There is. The concealing layer 4 includes a first ink layer 7 made of one or more colors of ink that covers the entire bar code pattern 2 (printing layer 3), and a second ink layer formed on the first ink layer 7. The ink layer 8 has a two-layer structure or a multilayer structure of more than two layers.

The second ink layer 8 is composed of an assembly of a large number of small and independent multicolor ink layers 8a, 8b, 8c,
Unlike the first ink layer 7, it is a discontinuous layer. As shown in FIG. 6, the second ink layer 8 allows multi-color small symbols (A, B, C, D ... In the case of this embodiment).
...) are printed innumerably.

Examples of the color pigments for the ink layers 6, 7, and 8 include carbon black, red iron oxide (red iron oxide),
Inorganic compounds such as cadmium red, dark blue (milory blue) and ultramarine (ultramarine), or organic compounds such as azo pigments and phthalocyanine pigments are appropriately used.

The size of the pattern (pattern, symbol, etc.) 5 is, for example, 5 mm or less, preferably 3 mm or less, and the small patterns 5 are irregularly or regularly formed innumerably.

The total thickness of the hiding layer 4 is approximately 0.5 to 20 μm, which is almost the same as the thickness of the bar code pattern 2 (printing layer 3).
It is preferable to regulate to the range of (1), because the presence of the bar code pattern 2 (printing layer 3) will not be apparent even by touch.

Although not shown, the reader for optically reading the bar code pattern 2 is provided with a light emitting element (infrared photodiode) and a light receiving element as a pair. FIG. 8 is a timing chart showing the light emission timing of the light emitting element, the state of excitation light from the barcode pattern 2 and the output state of the light receiving element.

The light emitting element as shown in (a) of the figure, on at substantially equal time intervals are both lighting time T ₁ and the extinguishing time T ₂ 500 .mu.sec, turning off the drive, intermittently against the bar code pattern 2 It is designed to irradiate infrared rays. S ₁ in the figure indicates a lighting signal of the light emitting element 9.

(B) of the figure shows a state in which the fluorescent fine particles in the bar code pattern 2 are excited by the irradiation of infrared rays to emit light, and until the lighting of the light emitting element is completed,
The output increases. Even after the irradiation from the light emitting element is stopped, the afterglow (excitation light) emitted from the barcode pattern 2 can be detected by the light receiving element. Since this afterglow decreases with time, a reference value Vs is set in advance, and by comparison with this reference value Vs, a rectangular signal S ₃ corresponding to the barcode pattern 2 is obtained immediately after the light emitting element is turned off. be able to.

The printing layer 3 and the concealing layer 4 can be formed by, for example, thermal transfer, ink jet, offset printing, screen printing or gravure printing. Among them, in particular, the method of sequentially forming the printing layer 3 and the hiding layer 4 by thermal transfer using a thermal transfer ink ribbon enables printing containing a high concentration of phosphor fine particles and has a desired thickness of the layer. You can use it for reasons such as surely getting it.

In the above embodiment, the case of the card is explained, but
The latent image forming member of the present invention also has the following uses and features.

1. Factory automation (FA) related Partial control during assembly of automobiles, that is, by vehicle model, export destination country, manufacturing date, lot, etc., can be managed without using an invisible latent image mark. .

2. Even if marking is made on a black object such as a tire or a transparent object such as glass or plastic, which cannot be read by a conventional reflective bar code, the mark can be read.

3. Since it is possible to read the latent image mark by printing letters or designs on the latent image mark,
Small spaces such as product price tags and product tags can be effectively used.

4. The above 1. And 3. For the same reason as above, it is effective for products such as cosmetics and medicines that emphasize design, or for various cosmetic boxes and packages that require a high-class feeling.

5. The latent image marks can be read even in environments where conventional reflective barcodes cannot be used because they are contaminated with oil and dust at factories and sites.

6. The above 1. And 3. For the same reason as above, the management information of the manufacturer is hidden as a hidden code in the distribution management, slip management, delivery slip to the customer (usually, the delivery slip contains only the information required by the customer in the paper and format specified by the customer). You can put it in.

7. Information can be inserted into a card-like object as a hidden code and used as a game card (bar code game).

8. The above 1. And 3. For the same reason as above, if it is used as a book management or a book management, the design is not damaged.

9. Since it is extremely difficult to forge, alter, and falsify, it can be applied to room entry / exit management, attendance / attendance management, hotel key cards, etc.

10. Counterfeiting or alteration of securities or stock certificates,
Tampering can be prevented.

11. Forgery, alteration, and tampering of credit cards, cash cards, telephone cards, etc. can be prevented.

12. Prevents forgery, alteration, and falsification of student ID cards, ID cards, etc., and also enables downsizing and space saving.

13. Forgery, alteration, and falsification of stamp cards, point cards, etc. can be prevented, and downsizing and space saving are possible.

14. It is possible to prevent counterfeiting, alteration, and falsification of betting tickets such as betting tickets and car tickets.

15. Introduced into the pachinko prize exchange system to prevent forgery, alteration and tampering

[0063]

As described above, according to the present invention, since the concealing layer composed of two or more colors is formed, even if unevenness is formed on the surface of the concealing layer due to the presence of the printing layer, the concealing layer is visually recognized. It becomes impossible to recognize the existence of the print layer, and the concealing effect is sure and the effects such as forgery, alteration, and tampering are sure.

[Brief description of drawings]

FIG. 1 is a plan view of a card according to an embodiment of the present invention before forming a hiding layer.

FIG. 2 is an enlarged cross-sectional view of a main part of the card before forming a masking layer.

FIG. 3 is a plan view of the card after a hiding layer is formed.

FIG. 4 is an enlarged cross-sectional view of a main part of the card after forming a masking layer.

FIG. 5 is a characteristic diagram showing the relationship between the thickness of the printed layer and the output voltage.

FIG. 6 is a plan view showing a modified example of the present invention after forming a concealing layer of a card.

FIG. 7 is an enlarged cross-sectional view of a main part of the card after forming a masking layer.

FIG. 8 is a timing chart of a light emitting element, a light receiving element and the like of an optical reading device for reading a card according to an embodiment of the present invention.

FIG. 9 is an enlarged cross-sectional view of a main part of a conventionally proposed card after forming a hiding layer.

[Explanation of Codes] 1 Card Base Material 2 Bar Code Pattern 3 Printing Layer 4 Concealment Layer 5 Pattern 6a, 6b Ink Layer 7 First Ink Layer 8 Second Ink Layer 8a, 8b Ink Layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tsunemi Oiwa 1-88 1-Tora Tora, Ibaraki City, Osaka Prefecture Hitachi Maxell Co., Ltd.

Claims (5)

[Claims] 1. A substrate, a printed layer of a latent image pattern containing a phosphor excited by infrared rays above the substrate, and an infrared-transparent ink above the printed layer to form the printed layer. A latent image forming member having a hiding layer for hiding, wherein the hiding layer is composed of two or more colors of ink. 2. The latent image forming member according to claim 1, wherein the thickness of the printing layer is regulated in the range of 0.5 to 20 μm. 3. The latent image forming member according to claim 1, wherein the ink layer of the hiding layer is substantially continuous. 4. The hiding layer according to claim 1,
It is composed of a continuous first ink layer covering almost the entire surface of the printing layer, and a second ink layer composed of an assembly of a large number of small independent ink layers formed on the first ink layer. A latent image forming member characterized by being present. 5. The latent image forming member according to claim 1, wherein the printing layer and the hiding layer are composed of a thermal transfer ink layer.