JPH0758416B2 - Copy prevention - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a copy protection method in which when original information is copied, it is not faithfully copied and becomes unreadable.

<Prior Art> With the recent widespread development of electronic copying machines, anyone can easily make a faithful copy of a copy original. However, the ease of copying is not used only for legitimate purposes, and for example, it is increasingly used for illegal purposes such as those that infringe copyrights and things that you do not want to copy such as confidential documents. However, some countermeasures are strongly desired and some proposals have been made. One of the representative examples is that the wavelength characteristic of light is used to make information by the difference in color tone between the image part and the non-image part by modifying the copy document itself, and the reflectance is made almost the same to make copying impossible. There is a way to However, with this method, the copy document itself becomes very difficult to read,
It has the drawback that the original document itself cannot be reused.
As another method, the copy original is subjected to a specific process, and the copy machine senses the processed image so that the copy operation is stopped or the copy content is made unreadable. Proposals have been made to provide a copying machine with a means for hindering the regular copy function, such as the following. However, this method has a drawback that the apparatus becomes complicated.

<Problems to be Solved by the Invention> In view of the above situation, the present invention makes a copy original unreadable in a copy of a document or the like which is not desired to be copied without making it difficult to read and without using a complicated device. It provides a copy protection method.

<Means for Solving Problems> The present invention relates to a copying machine including an exposure system and an image forming system, in which a second polarizer is provided in proximity to an original formed by adhering the first polarizer to the surface in advance. This is a copy prevention method in which an image is exposed with an exposure system in which at least one of the first and second polarizers is interposed along the optical axis from the light source and the polarization directions are randomly oriented.

That is, in the copy protection method of the present invention, for example, in a company or the like, an administrator selects a document which is difficult to be copied from several documents, and a polarizer is attached to the surface of the document (original) to store it. This keeps the original legible so that if someone tries to copy the original, it will not be possible to copy it in combination with the polarization function of the original plate of an electronic copier or the like. It is a thing.

The copy protection method of the present invention will be described with reference to the drawings by taking an electronic copying machine as an example. FIG. 1 shows a copy protection method 1 of the present invention.
One of the embodiments is shown, which is a platen glass 6 of an electronic copying machine.
The second polarizer 4 is adhered to by an adhesive 5,
For the original 1, the first polarizer 3 has the adhesive 2 to prevent copy.
Is glued by. When this is copied, the light 8 from the light source 7 is a normal copy when the polarization directions of the first and second polarizers are the same, but when the polarization directions are deviated, the light is blocked. However, the non-image part will be imaged like the image part. Thus, the present invention is a method of preventing copying by having first and second polarisers in close proximity to an exposure system.

Here, as a means for allowing the first and second polarizers to exist in the exposure system, the following means can be taken as a specific example. First, for the first polarizer, a sheet-like material having a polarization characteristic such as a polarizing film may be attached to the surface of the original document whose copy is desired to be prevented. On the other hand, the second polarizer is provided by sticking a polarizing film on the surface of the platen glass of the copying machine, or using a laminated glass in which two polarizing films are sandwiched as the platen glass. . In the present invention, the second polarizer is provided in the exposure system in the vicinity of the first polarizer, and in this case, the method of superposing them closely as in the example of FIG. 1 is more preferable.
Incidentally, the exposure system in the present invention means from the light source to the latent image formation.

When providing the first and second polarizers as described above, what is important is that these polarizers must be provided so as not to be easily removed. For example, when a polarizing film is provided on the surface of a document for which copying is desired to be prevented, it is necessary to prevent the film from being adhered to and removed from the surface of the document by providing an adhesive layer on one side of the polarizing film. That is, if the polarizing film and the surface of the original are adhered to each other with an adhesive strength such that the original will be damaged if the polarizing film is peeled off, the polarizing film can be peeled off and forcibly copied. It can be prevented.

In the present invention, at least one of the first and second polarizers provided in the exposure system needs to have a random polarization direction. Random here does not have the polarization characteristics in a fixed direction as shown in FIGS. 2 (a), (b), and (c) within the range of the size of the document for which copying is desired to be prevented, and FIG. This means that the polarization directions are oriented in multiple directions within the same plane as shown in (a), (b) and (c). That is, as shown in FIG. 2C, a polarizing film having a characteristic of polarizing in a certain fixed direction is cut into small pieces of an appropriate size, and the pieces are arbitrarily arranged to polarize in one sheet. You may use the synthetic | combination polarizing film synthesize | combined so that the direction might be multidirectional. It should be noted that such a polarizer having random polarization directions may be provided as both the first and second polarizers.

In addition, the polarizers used as the first and second polarizers used in the present invention are, for example, a polarized light film such as a polymer dichroic polarizing film obtained by adsorbing iodine molecules or dye molecules on a polyvinyl alcohol film. Films are preferred. The polarizer used here may be colorless transparent or colored transparent, and when using a colored one,
For example, in the exposure system, the one colored in any color can be used as long as it does not affect the exposure amount and color sensitivity of the copying machine, and as the original, it is not difficult to read the original.

As the copying machine to which the present invention is applied, all types of copying machines that optically expose a document are applied, and include a reflection exposure type electronic copying machine, a transmission exposure type diazo copying machine, and the like. Incidentally, the image forming system referred to in the present invention is, for example, in the case of a PPC electronic copying machine, latent image formation such as latent image formation on a photoconductor, development with a developer, transfer of an image to copy paper, fixing and the like. This is the process of imaging.

<Operation> The present invention applies the polarization property to the copy protection function of a copying machine. When two polarizing films are stacked, if the polarization directions are the same, the light transmission does not hinder the two polarizing films. It is based on the principle that although an object can be seen through, it becomes difficult for light to pass therethrough as its polarization direction shifts, and an object cannot be seen through two polarizing films.

That is, when both the exposure process and the original are simply given the polarization characteristics in a constant direction as shown in FIGS. 2A, 2B, and 2C, in some cases, the polarization directions of both are shifted and However, if the original is rotated and moved so that the polarization directions of the two coincide with each other, no copy preventing function can be obtained.

According to the present invention, in order to eliminate the case where such a copy protection function is not obtained, the polarization direction in the exposure system and the polarization direction on the document side are different even if the document is placed on the platen of the copying machine at any angle. The polarizing property is added so that there is always a portion (there is a deviation of 45 ° to 90 °).

<Example> Next, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto.

Example 1 A polarizing film having random polarization directions as shown in FIG. 3A was attached to the surface of a platen glass of an electronic copying machine,
On the other hand, when a polarizing film having a constant polarization direction as shown in FIG.
A black solid portion was also generated in the non-image portion of the original, making it unreadable. In addition, the electronic copying machine is a commercially available Sharp SF-8100,
Three models, EP-350Z manufactured by Minolta and DC-513Z manufactured by Mita, were used.

Example 2 A polarizing film having a constant polarization direction as shown in FIG. 2 (a) is attached to the surface of a platen glass of an electronic copying machine, while the polarization direction as shown in FIG. 3 (a) is random. When a transparent polarizing film was pasted on the surface of the original to make a copy, it was not readable in all three types of copying machines as in Example 1.

Example 3 A polarizing film is chopped into small pieces of 1 cm square so that the polarizing directions are in the directions of two pieces facing each other as shown in FIG. 2 (a) or (b), and another polarizing film of the same kind is further cut. Second
Make sure that the polarization direction is diagonal as shown in Figure (c).
Chopped pieces 1 cm square. After mixing these two kinds of small pieces well, put them on a 12 μm PET film in a grid pattern and paste them with an adhesive to synthesize randomly polarized light as shown in Fig. 3 (c). A polarizing film was produced.

Stick the polarizing film with random polarization direction produced as described above on the surface of the platen glass of the electronic copying machine,
On the other hand, when a polarizing film having a constant polarization direction as shown in FIG.
As in Example 1, all three types of copying machines were unreadable.

Example 4 When a polarizing film having random polarization directions as shown in FIG. 3B was attached and copied on both the surface of the platen glass of the electronic copying machine and the surface of the original, the same result as in Example 1 was obtained. Both types of copiers were unreadable.

<Effects of the Invention> The present invention can be simplified by attaching a polarizing film having a random polarization direction to a document table of an electronic copying machine and attaching the polarizing film to a copy prevention document or the like. The method can form a copy protection system. Further, when an ordinary copy is made using the electronic copying machine having the polarizing film attached to the original table as described above, the polarizing film need not be attached to the original, so that the present invention is highly applicable.

[Brief description of drawings]

FIG. 1 shows an example of the copy prevention method of the present invention, and is a cross-sectional view of a document table portion of an electronic copying machine. The second
FIG. 3 and FIG. 3 show specific examples of the polarizer used in the present invention, and the polarization direction is represented by a line. Here, FIGS. 2 (a), (b), and (c) are examples of a polarizer having a polarization characteristic in a fixed direction, and FIGS. 3 (a), (b), and (c) have random polarization directions. It is an example of such a polarizer. 1 ... Original, 2,5 ... Adhesive 3 ... First polarizer, 4 ... Second polarizer 6 ... Original glass, 7 ... Light source

Claims (1)

[Claims] 1. A copying machine comprising an exposure system and an image forming system, wherein a second polarizer is interposed along the optical axis from a light source in the vicinity of an original formed by adhering the first polarizer to the surface in advance. A method of copy protection, wherein at least one of the first and second polarizers is imagewise exposed with an exposure system in which polarization directions are randomly oriented.