JP7707752B2 - Pressure-bonding sheet - Google Patents

Description

The present invention relates to a pressure-sensitive sheet to which multiple pieces of paper connected via folds are releasably attached, and in particular to a technology for preventing counterfeiting.

Forgery crimes have been occurring frequently in the past with prepaid cards, various admission tickets, gift certificates, stock certificates, and other valuable securities because they are widely circulated and can be converted into cash relatively easily. In particular, with the recent improvement in performance and widespread use of copying machines such as color copiers, it has become relatively easy to produce counterfeit products that are indistinguishable from genuine products, and measures against counterfeiting are required.

Patent Document 1 discloses a pressure-bonded postcard that has been implemented with measures against such counterfeiting. In the pressure-bonded postcard disclosed in Patent Document 1, for example, the watermark is created by using a method in which the thickness of the paper that will become the watermark is reduced during paper production to create a white watermark, or a method in which a transparent ink containing wax is printed at the same time as the image is printed to increase the light transmittance of the paper to create a pseudo-watermark, thereby making it impossible to counterfeit by copying, etc.

JP 2000-326662 A

However, the method disclosed in Patent Document 1 involves partially thinning the paper thickness during paper production and using special ink, which places a heavy burden on the manufacturing process and makes it difficult to manufacture.

In the field of counterfeit prevention as described above, a technique is often used in which a latent image printing layer is formed on a substrate in a form in which a latent image pattern is revealed when the latent image is copied, and the latent image pattern is revealed when the latent image is copied. In such a case in which a latent image printing layer for revealing a latent image pattern is formed on a substrate, the latent image printing layer is composed of a pattern component that constitutes the latent image pattern and a background component that constitutes the other area, so it is necessary to print a certain area as the latent image printing layer. On the other hand, in a pressure-bonded postcard in which two pieces of paper are peelably attached, a so-called pre-gluing process is adopted in which printing is performed after a pseudo-adhesive layer is laminated on a substrate, and if printing is performed on a certain area like the above-mentioned latent image printing layer, there is a risk that the adhesive force for adhering the two pieces of paper cannot be sufficiently secured. In the Postal Law, a pressure-bonded postcard in which two pieces of paper are peelably attached must have the two pieces of paper securely attached on their entire surfaces, and it is not preferable for a part of the pieces to peel off during mailing due to insufficient adhesive force.

The present invention was made in consideration of the problems with the conventional technology as described above, and aims to provide a pressure-sensitive sheet to which multiple pieces of paper connected via folds are releasably attached, which ensures sufficient adhesive strength for attaching the multiple pieces of paper and can be easily manufactured to prevent counterfeiting.

In order to achieve the above object, the present invention provides
A pressure-sensitive sheet in which a first piece of paper and a second piece of paper connected via a folding portion are peelably attached,
a pseudo-adhesive layer laminated on each of the adhesive surfaces of the first piece of paper and the second piece of paper, releasably adhering the first piece of paper to the second piece of paper;
A latent image printing layer is formed on at least a portion of the pseudo-adhesive layer in such a manner that a latent image pattern is revealed by being copied,
The latent image printing layer has a dot density of 7% or more and 18% or less.

In the present invention configured as described above, in the pressure-bonded sheet to which the first and second pieces of paper connected via the fold are releasably attached, a latent image printed layer is formed on at least a portion of the pseudo-adhesive layer laminated on substantially the entire adhesive surface of the first and second pieces of paper, in a form that allows a latent image pattern to appear when copied, thereby preventing counterfeiting. Since the latent image printed layer has a dot density of 7% or more, the latent image pattern is reliably revealed when copied, while the dot density of the latent image printed layer is 18% or less, sufficient adhesive strength is ensured when the first and second pieces of paper are releasably attached, and counterfeiting is prevented by the easy manufacturing method of forming a latent image printed layer on the pseudo-adhesive layer.

Furthermore, if the latent image printing layer is formed on each of the first and second pieces of paper in an area that does not overlap when the first and second pieces of paper are folded at the fold, sufficient adhesive strength is ensured over the entire surface when the first and second pieces of paper are removably attached.

In addition, when the latent image printing layer is formed in the area of each of the first and second pieces of paper that overlap when the first and second pieces of paper are folded at the fold, the dot density of the latent image printing layer is 7% or more and 14% or less to ensure even more sufficient adhesive strength.

According to the present invention, in a pressure-bonded sheet to which a first piece of paper and a second piece of paper connected via a fold are releasably attached, a latent image printed layer formed on a pseudo-adhesive layer laminated over substantially the entire bonding surfaces of the first piece of paper and the second piece of paper in a form that reveals a latent image pattern when copied has a dot density of 7% or more, which reliably reveals the latent image pattern when copied, while the dot density of the latent image printed layer is 18% or less, which ensures sufficient adhesive strength for bonding the two pieces of paper together and makes it possible to prevent counterfeiting with a simple manufacturing method.

In addition, when the latent image printing layer is formed on each of the first and second pieces of paper in an area that does not overlap when the first and second pieces of paper are folded at the fold, when the first and second pieces of paper are releasably attached, sufficient adhesive strength can be ensured over the entire surface.

In addition, when the latent image printing layer is formed in the area where the first piece of paper and the second piece of paper overlap when the first piece of paper and the second piece of paper are folded at the fold, the dot density of the latent image printing layer is 7% or more and 14% or less, thereby ensuring even more sufficient adhesive strength.

FIG. 1 shows one embodiment of the pressure-bonded sheet of the present invention, where (a) is a diagram showing one side, (b) is a cross-sectional view taken along line A-A' in (a), (c) is a cross-sectional view taken along line B-B' in (a), and (d) is a diagram showing the other side. 2A to 2C are diagrams for explaining a method for manufacturing the pressure-bonded postcard shown in FIG. 1 . 2 is a diagram for explaining a method of use when opening the pressure-bonded postcard shown in FIG. 1 and the action at that time. FIG. 2 is a diagram for explaining the action when the surface of the pressure-bonded postcard shown in FIG. 1 on which the latent image printing layer is formed is copied by a copy machine. FIG. 2 is a diagram showing the results of evaluating the adhesive strength between the main piece and the concealing piece and the visibility of the latent image pattern when copied in accordance with the dot density of the latent image printed layer in the pressure-bonded postcard shown in FIG. 1 . 1A and 1B are diagrams showing another embodiment of the pressure-bonding sheet of the present invention, in which (a) is a diagram showing one side, (b) is a cross-sectional view taken along line A-A' in (a), and (c) is a diagram showing the other side.

Below, an embodiment of the present invention will be described with reference to the drawings.

Figure 1 shows one embodiment of the pressure-bonded sheet of the present invention, where (a) is a diagram showing one side, (b) is a cross-sectional view taken along the line A-A' in (a), (c) is a cross-sectional view taken along the line B-B' in (a), and (d) is a diagram showing the other side.

As shown in FIG. 1, the pressure-bonded sheet in this embodiment is a pressure-bonded postcard 1 in which a pseudo-adhesive layer 3 is laminated over the entire surface of one side of a base sheet 2 in which a main body piece 20 and a concealing piece 10 are connected with one side of each piece as a connecting side, a latent image printed layer 21 is laminated over a portion of the pseudo-adhesive layer 3 of the main body piece 20, and a latent image printed layer 11 is laminated over a portion of the pseudo-adhesive layer 3 of the concealing piece 10. Note that the pseudo-adhesive layer 3 does not have to be laminated over a portion of the base sheet 2, and even in this case, the pseudo-adhesive layer 3 is defined as being laminated over substantially the entire surface of the base sheet 2.

The main body piece 20 is the first piece of paper in the present invention. A fold 30 is formed at the connecting edge between the main body piece 20 and the concealment piece 10 by half slitting, creasing, sewing, etc., so that the base sheet 2 can be folded via the fold 30. The pseudo-adhesive layer 3 adheres the main body piece 20 and the concealment piece 10 in a manner that allows them to be peeled off and cannot be reattached after peeling when the base sheet 2 is folded via the fold 30 so that the surface on which the pseudo-adhesive layer 3 is laminated is on the inside, and a well-known layer can be used.

On the surface of the main body piece 20 on which the pseudo-adhesive layer 3 is laminated, a notification information display field 22 in which notification information to be notified using this pressure-bonded postcard 1 is printed is displayed by printing on the pseudo-adhesive layer 3, and a latent image print layer 21 is formed and laminated as described above in an area that does not overlap with the notification information display field 22. In addition, a type indication 23 is printed to indicate that the pressure-bonded postcard 1 is a mailing postcard.

The latent image printing layer 21 is composed of a pattern component 21a and a background component 21b. The pattern component 21a constitutes a latent image pattern that appears when the surface of the pressure-bonded postcard 1 on which the latent image printing layer 21 is formed is copied by a copy machine, as described later, and the background component 21b is the other area, which is not visible when the surface of the pressure-bonded postcard 1 on which the latent image printing layer 21 is formed is copied by a copy machine. The pattern component 21a can be formed using a well-known technique. For example, as the latent image printing layer 21, it is conceivable to print on the pseudo-adhesive layer 3 so that a plurality of dots whose sizes are slightly different from each other in the pattern component 21a and the background component 21b are arranged regularly or irregularly. When the sizes of the dots are made different in this way, it is conceivable to make the size of one dot constituting the pattern component 21a slightly larger than the size of one dot constituting the background component 21b. In such a configuration, when the latent image printing layer 21 is viewed with the naked eye, the dots that make up the pattern component 21a and the dots that make up the background component 21b cannot be clearly distinguished, making it difficult to recognize the latent image pattern caused by the pattern component 21a. However, when the latent image printing layer 21 is copied with a copy machine, the dots that make up the pattern component 21a and the dots that make up the background component 21b are clearly distinguished, making the latent image pattern caused by the pattern component 21a clearly visible. In this way, the latent image printing layer 21 has a latent image pattern in a part of it that is difficult to see with the naked eye but appears when copied with a copy machine.

On the side of the main body piece 20 opposite the side on which the pseudo-adhesive layer 3 is laminated, a background pattern printing layer 24 is laminated over almost the entire surface.

The concealing piece 10 is the second piece of paper in the present invention. On the surface of the concealing piece 10 on which the pseudo-adhesive layer 3 is laminated, a notification information display field 12 in which notification information to be notified using this pressure-bonded postcard 1 is printed is displayed on the pseudo-adhesive layer 3 by printing, and the latent image printing layer 11 is formed and laminated as described above in an area that does not overlap the notification information display field 12. Note that the latent image printing layer 11 is formed in an area that does not overlap with the latent image printing layer 21 of the main body piece 20 when the base sheet 2 is folded via the folding portion 30. In addition, the concealing piece 10 has a hole portion 13 for exposing the type display 23 in an area facing the type display 23 of the main body piece 20 when the base sheet 2 is folded via the folding portion 30, and a notch 14 is formed by cutting out one corner that is not adjacent to the folding portion 30.

The latent image printing layer 11 is composed of a pattern configuration portion 11a and a background configuration portion 11b. The pattern configuration portion 11a, like the pattern configuration portion 21a of the main body piece 20, constitutes a latent image pattern that appears when the surface of the pressure-bonded postcard 1 on which the latent image printing layer 11 is formed is copied by a copy machine, and the background configuration portion 11b is the other area, and like the background configuration portion 21b of the main body piece 20, it is not visible when the surface of the pressure-bonded postcard 1 on which the latent image printing layer 11 is formed is copied by a copy machine. For example, by making the pattern configuration portion 11a and the background configuration portion 11b similar to the pattern configuration portion 21a and the background configuration portion 21b of the main body piece 20, when the latent image printing layer 11 is visually recognized by the naked eye, the latent image pattern by the pattern configuration portion 11a is difficult to recognize, and when the latent image printing layer 11 is copied by a copy machine, the latent image pattern by the pattern configuration portion 11a is clearly visible.

On the side of the concealing piece 10 opposite to the side on which the pseudo-adhesive layer 3 is laminated, there is a destination information display area 15 on which destination information indicating the delivery destination of the pressure-bonded postcard 1 is printed.

As described above, the latent image printing layers 11, 21 are not limited to those printed by printing a plurality of dots, the size of which is slightly different between the pattern constituent parts 11a, 21a and the background constituent parts 11b, 21b, in a regular or irregular arrangement. Instead, they may be printed on the pseudo-adhesive layer 3 in a manner that prints a plurality of parallel lines, of which only the pattern constituent parts 11a, 21a have different line widths or directions, so long as they are copied to reveal a latent image pattern.

The manufacturing method for the pressure-bonded postcard 1 configured as described above is described below.

Figure 2 is a diagram for explaining the manufacturing method of the pressure-bonded postcard 1 shown in Figure 1.

When manufacturing the pressure-bonded postcard 1 shown in Figure 1, first, a pseudo-adhesive layer 3 is laminated by applying a pseudo-adhesive that allows the postcard to be peeled off after application but cannot be reapplied after removal to the entire surface of one side of the base sheet 2 (Figure 2(a)).

Next, on the surface of the base sheet 2 on which the pseudo-adhesive layer 3 is laminated, the latent image printing layers 11, 21 having the above-mentioned configuration are formed by printing on each of the concealment piece 10 and the main body piece 20, and further, lines indicating the notification information display areas 12, 22 are printed (Fig. 2(b)). In addition, a background pattern printing layer 24 is laminated by printing on the surface of the main body piece 20 opposite to the surface on which the pseudo-adhesive layer 3 is laminated.

Next, the notification information 12a, 12b to be notified using this pressure-bonded postcard 1 is printed in the notification information display area 12 on the concealing piece 10 and the notification information display area 22 on the main body piece 20 (Figure 2 (c)).

Then, the sheet is folded at the folding portion 30 so that the surface on which the pseudo-adhesive layer 3 is laminated faces inward, and the main body piece 20 and the concealment piece 10 are releasably attached by the pseudo-adhesive layer 3.

The following describes how to use the above-mentioned pressure-bonded postcard 1 and its effects.

Figure 3 is a diagram to explain how to use the sealed postcard 1 shown in Figure 1 when opening it and the action that occurs during this process.

As shown in FIG. 3(a), the pressure-bonded postcard 1 shown in FIG. 1 is delivered to the destination of the pressure-bonded postcard 1 according to the destination information 15a printed in the destination information display area 15 of the concealing piece 10, and then the concealing piece 10 is peeled off from the main piece 20 to open it. At that time, because the concealing piece 10 has a notch 14 at its corner, it can be easily peeled off from the main piece 20 using this notch 14 as the peeling start end.

When the concealing piece 10 is peeled off from the main body piece 20, as shown in FIG. 3(b), the notification information 12a printed in the notification information display field 12 of the concealing piece 10 and the notification information 22a printed in the notification information display field 22 of the main body piece 20 become visible, and the notification information 12a, 22a is thereby notified to the destination of the pressure-bonded postcard 1. The latent image printing layer 21 formed on the main body piece 20 has a pattern component 21a that causes a latent image pattern to appear in the background component 21b, but when the latent image printing layer 21 is viewed with the naked eye, the dots that make up the pattern component 21a and the dots that make up the background component 21b cannot be clearly distinguished, making it difficult to recognize the latent image pattern caused by the pattern component 21a. Similarly, the latent image printing layer 11 formed on the concealing piece 10 has a pattern component 11a that causes a latent image pattern to appear in the background component 11b, but when the latent image printing layer 11 is viewed with the naked eye, the dots that make up the pattern component 11a and the dots that make up the background component 11b cannot be clearly distinguished, making it difficult to recognize the latent image pattern caused by the pattern component 11a.

Figure 4 is a diagram to explain the effect when the surface of the pressure-bonded postcard 1 shown in Figure 1 on which the latent image printing layers 11 and 21 are formed is copied by a copy machine.

In the pressure-bonded postcard 1 shown in FIG. 1, the latent image printing layer 11, 21 is printed on the pseudo-adhesive layer 3 so that multiple dots, the size of which is slightly different between the pattern components 11a, 21a and the background components 11b, 21b, are arranged regularly or irregularly. The size of each dot that constitutes the pattern components 11a, 21a is slightly larger than the size of each dot that constitutes the background components 11b, 21b. Therefore, when the latent image printing layer 11, 21 is copied with a copy machine, the dots that constitute the pattern components 11a, 21a and the dots that constitute the background components 11b, 21b are clearly distinguished. As a result, for example, as shown in FIG. 4, the background components 11b, 21b cannot be seen, while the latent image patterns 16, 25 of the pattern components 11a, 21a are clearly visible.

In this way, in the pressure-bonded postcard 1 shown in Figure 1, the latent image patterns 16, 25 formed by the latent image printing layers 11, 21 are difficult to recognize when viewed with the naked eye, but when copied with a copy machine, the latent image patterns 16, 25 are clearly visible, which helps to prevent counterfeiting.

The dot density of the latent image printing layers 11 and 21 is explained below.

As in the above-mentioned pressure-bonded postcard 1, when the pseudo-adhesive layer 3 is laminated on the base sheet 2, the lines indicating the notification information display areas 12, 22 are printed on the pseudo-adhesive layer 3, and the latent image printing layers 11, 21 are formed by printing, depending on the dot density of these prints, there is a risk that the adhesive strength for adhering the main body piece 20 and the concealment piece 10 may not be sufficiently secured. In particular, as described above, the latent image printing layers 11, 21 are composed of the pattern components 11a, 21a that constitute the latent image pattern and the background components 11b, 21b that constitute the other areas, and therefore it is necessary to print the latent image printing layers 11, 21 over a certain area, so there is a high possibility that the adhesive strength for adhering the main body piece 20 and the concealment piece 10 may not be sufficiently secured.

Therefore, in this embodiment of the pressure-bonded postcard 1, the dot density of the latent image printing layers 11, 21 is adjusted to ensure sufficient adhesive strength for adhering the main body piece 20 and the concealing piece 10 together.

Figure 5 shows the results of evaluating the adhesive strength between the main body piece 20 and the concealing piece 10 and the visibility of the latent image pattern when copied in accordance with the dot density of the latent image printing layers 11, 21 in the pressure-bonded postcard 1 shown in Figure 1.

As with the pressure-bonded postcard 1 shown in FIG. 1, the pseudo-adhesive layer 3 is laminated on the entire surface of one side of the base sheet 2 in which the main body piece 20 and the concealing piece 10 are configured to be foldable via the folding portion 30. As shown in FIG. 5, the dot density of the latent image printing layers 11, 21 formed and laminated on the pseudo-adhesive layer 3 was changed, and the visibility of the latent image pattern during copying and the adhesive strength between the main body piece 20 and the concealing piece 10 were evaluated. Regarding the visibility of the latent image pattern during copying, the case where the latent image pattern is clearly manifested after copying and can be clearly distinguished before and after copying is marked as "◯", the case where the latent image pattern is manifested after copying and can be distinguished before and after copying is marked as "△", and the case where there is no contrast between the pattern constituent parts 11a, 21a and the background constituent parts 11b, 21b and the latent image pattern is not manifested after copying is marked as "X". In addition, with regard to the adhesive strength between the main body piece 20 and the concealment piece 10, adhesive strength of 1.60 N/6" or more when sealed with a GAP of 300 μm was rated as "◯", adhesive strength of 1.00 N/6" or more but less than 1.60 N/6" when sealed with a GAP of 300 μm was rated as "△", and adhesive strength of less than 1.00 N/6" when sealed with a GAP of 300 μm was rated as "X".

Regarding the visibility of the latent image pattern during copying, as shown in FIG. 5, if the dot density of the latent image printing layers 11 and 21 is 7% or more, the latent image pattern appears after copying, and the latent image pattern can be distinguished before and after copying.

As for the adhesive strength between the main body piece 20 and the concealing piece 10, as shown in FIG. 5, in the case of a screen in which a latent image printing layer is laminated on only one of the main body piece 20 and the concealing piece 10 (single-sided screen), if the dot density of the latent image printing layer is 18% or less, an adhesive strength of 1.60 N/6" or more is obtained when sealed with a GAP of 300 μm, and if the dot density of the latent image printing layer is 19% to 20%, an adhesive strength of 1.00 N/6" or more and less than 1.60 N/6" is obtained when sealed with a GAP of 300 μm.

In other words, even if the latent image printing layer is provided on each of the main body piece 20 and the concealing piece 10, as long as it is formed in an area that does not overlap when the main body piece 20 and the concealing piece 10 are folded via the folding portion 30, by making the dot density of the latent image printing layer 20% or less, an adhesive strength of 1.00 N/6" or more and less than 1.60 N/6" can be obtained when sealed with a GAP of 300 μm, and further, by making the dot density of the latent image printing layers 11 and 21 18% or less, an adhesive strength of 1.60 N/6" or more can be obtained when sealed with a GAP of 300 μm, and sufficient adhesive strength can be ensured over the entire surface.

On the other hand, as shown in FIG. 5, for a screen in which a latent image printing layer is laminated on both the main body piece 20 and the concealing piece 10 (double-sided screen), if the dot density of the latent image printing layer is 14% or less, an adhesive strength of 1.60 N/6" or more is obtained when sealed with a GAP of 300 μm, and if the dot density of the latent image printing layer is 15% to 20%, an adhesive strength of 1.00 N/6" or more and less than 1.60 N/6" is obtained when sealed with a GAP of 300 μm.

In other words, when the latent image printing layer is formed in the area where the main body piece 20 and the concealing piece 10 overlap when the main body piece 20 and the concealing piece 10 are folded via the fold 30, by setting the dot density of the latent image printing layer to 20% or less, an adhesive strength of 1.00 N/6" or more and less than 1.60 N/6" can be obtained when sealed with a GAP of 300 μm, and further, by setting the dot density of the latent image printing layer to 14% or less, an adhesive strength of 1.60 N/6" or more can be obtained when sealed with a GAP of 300 μm, ensuring an even more sufficient adhesive strength.

In this way, in the pressure-bonded postcard 1 in which the main body piece 20 and the concealing piece 10 connected via the fold 30 are releasably attached, the latent image printing layers 11, 21 formed on the pseudo-adhesive layers 3 laminated on the adhesion surfaces of the main body piece 20 and the concealing piece 10, respectively, have a dot density of 7% or more, which reliably reveals the latent image pattern when copied, while the dot density of the latent image printing layers 11, 21 is 18% or less, which ensures sufficient adhesive strength for attaching the main body piece 20 and the concealing piece 10, and counterfeiting can be prevented by the simple manufacturing method of forming the latent image printing layers 11, 21 on the pseudo-adhesive layers 2.

In addition, if the latent image printing layers 11, 21 are formed in areas of the main body piece 20 and the concealing piece 10 that do not overlap when the main body piece 20 and the concealing piece 10 are folded via the fold 30, then when the main body piece 20 and the concealing piece 10 are releasably attached, a more sufficient adhesive strength can be ensured over the entire surface of the concealing piece 10 and the main body piece 20.

In addition, even if the latent image printing layer is formed in the area where the main body piece 20 and the concealing piece 10 overlap when the main body piece 20 and the concealing piece 10 are folded at the fold, by setting the dot density of the latent image printing layer to 7% or more and 14% or less, more sufficient adhesive strength can be ensured.

Other Embodiments
FIG. 6 is a diagram showing another embodiment of the pressure-bonding sheet of the present invention, in which (a) is a diagram showing one side, (b) is a cross-sectional view taken along line AA' in (a), and (c) is a diagram showing the other side.

As shown in FIG. 6, the pressure-bonded sheet in this embodiment is a pressure-bonded postcard 101 that differs from that shown in FIG. 1 in that a notification information display area 122 is provided in the area of the main body piece 120 where the latent image printing layer 121 consisting of the pattern component 121a and the background component 121b is laminated, and a notification information display area 112 is provided in the area of the concealing piece 110 where the latent image printing layer 111 consisting of the pattern component 111a and the background component 111b is laminated.

In the bonded postcard 101 constructed as described above, as in the case shown in FIG. 1, when viewed with the naked eye, the latent image printing layers 111, 121 cannot clearly distinguish between the dots constituting the pattern components 111a, 121a and the dots constituting the background components 111b, 121b, making it difficult to recognize the latent image pattern formed by the pattern components 111a, 121a. However, when copied using a copy machine, the dots constituting the pattern components 111a, 121a and the dots constituting the background components 111b, 121b are clearly distinguished, and as a result, for example, the background components 111b, 121b become indistinguishable, while the latent image pattern formed by the pattern components 111a, 121a is clearly visible. This makes it possible to prevent counterfeiting, and by setting the dot density of the latent image printing layers 111, 121 to 7% or more, the latent image pattern is reliably revealed when copied by a copy machine, while by setting the dot density of the latent image printing layers 111, 121 to 14% or less, sufficient adhesive strength can be ensured for attaching the main body piece 120 and the concealment piece 110 to each other.

In the embodiment shown in FIG. 6, the latent image printing layer 121 laminated on the main body piece 120 and the latent image printing layer 111 laminated on the concealing piece 110 are each approximately the same size as the notification information display area 122 of the main body piece 120 and the notification information display area 112 of the concealing piece 110, respectively. However, the latent image printing layer 121 laminated on the main body piece 120 and the latent image printing layer 111 laminated on the concealing piece 110 may be configured to overlap a portion of the notification information display area 122 of the main body piece 120 and the notification information display area 112 of the concealing piece 110, respectively.

In the above-mentioned embodiment, the main body piece 20, 120 and the concealing piece 10, 110 are connected via the fold 30, and the pressure-bonded postcard 1, 101 in which the main body piece 20, 120 and the concealing piece 10, 110 are removably attached by the pseudo-adhesive layer 3 has been described as an example. However, the same action can be achieved and the same effect can be obtained in a pressure-bonded sheet such as a pressure-bonded postcard in which three pieces of paper are connected via a fold and folded in a Z-shape and removably attached, by applying the above-mentioned configuration of the pseudo-adhesive layer 3 and the latent image printing layer 11, 21, 111, 121 to the adhesive surface.

REFERENCE SIGNS LIST 1,101 Pressure-bonded postcard 2 Base sheet 3 Pseudo-adhesive layer 10,110 Concealing piece 11,21,111,121 Latent image printed layer 11a,21a,111a,121a Pattern configuration section 11b,21b,111b,121b Background configuration section 12,22,112,122 Notification information display section 12a,22a Notification information 13 Hole 14 Cutout 15 Destination information display area 15a Destination information 16,25 Latent image pattern 20,120 Body piece 23 Type display 24 Background pattern printed layer 30 Folding section

Claims (3)

A pressure-sensitive sheet in which a first piece of paper and a second piece of paper connected via a folding portion are peelably attached,
a pseudo-adhesive layer that is laminated on substantially the entire surface of each of the first and second pieces of paper and that releasably attaches the first and second pieces of paper to each other;
A latent image printing layer is formed on at least a portion of the pseudo-adhesive layer in such a manner that a latent image pattern is revealed by being copied,
The latent image printing layer has a dot density of 7% or more and 18% or less. The pressure-bonding sheet according to claim 1,
A pressure-bonded sheet, in which the latent image printing layer is formed in an area of each of the first piece of paper and the second piece of paper that does not overlap when the first piece of paper and the second piece of paper are folded via the fold portion. The pressure-bonding sheet according to claim 1,
A pressure-bonded sheet, wherein the latent image printing layer is formed in an overlapping area of each of the first piece of paper and the second piece of paper when the first piece of paper and the second piece of paper are folded via the fold, and the dot density is 7% or more and 14% or less.