JPS63210879A - Copying method using diazo photosensitive paper - Google Patents

Abstract

PURPOSE:To visualize a bit of true information when necessary by copying the true information with a toner same in color as a diazo copying paper, and again copying other dummy information on it with another toner same in color as the diazo copying paper in order to form a confidential document. CONSTITUTION:A first confidential image is visualized by using a diazo photosensitive paper as a transfer paper, transferring a first toner image corresponding a first true original image and same in color as this transfer paper on the transfer paper, then, transferring the toner image corresponding to a second dummy original image with the other toner different in color from the first image on said transfer paper, and fixing the second toner image, and further, color developing the first confidential original image through a diazo developing process. So long as considerably much attention is not paid, only a bit of second original dummy information is read, and the confidential true information can be read by said latter processing, thus permitting confidential secret documents to be easily formed by using the electrophotographic copying machine and the diazo photosensitive paper.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for creating a confidential document using an electrophotographic copying machine and diazo photosensitive paper, as well as for reading the confidential document.

(Prior Art and its Problems) Recent improvements in the performance of copying machines and their widespread use have been remarkable, and anyone can now easily obtain large quantities of faithful copies of originals. Under such circumstances, materials that should not be copied or even important documents such as various certificates may be copied, or copies with parts of the document content altered may be judged as if they were the original image information. There is a risk that it may be transmitted.

For example, the following methods have been considered as means to prevent this.

(1) A method of coloring transfer paper with dye or pigment to absorb irradiated light equally in non-image areas and image areas, eliminating image exposure on the photoreceptor and preventing re-copying (Japanese Patent Laid-Open No. 54-52
538).

(2) A copy prevention method in which a camouflage pattern is applied to transfer paper and images are formed in different colors on the paper, thereby making it difficult to read because the ground pattern is also copied during copying (Japanese Patent Application Laid-Open No. 59-7704
7).

(3) A method in which a fluorescent material is present on the surface of a document, irradiated with excitation light, and the presence or absence of luminescence is detected and the copying operation is stopped (
JP-A-58-184967).

However, according to method (1), the manufacturing process becomes complicated and the documents produced become expensive because the transfer paper itself is colored with at least one of dyes and pigments during or after the printing process. . In addition, creating a copy-protected document using method (2) requires a printing method or other method to create a camouflage pattern that has the same reflectance in the non-image area and the image area, which is time consuming and costly. There are drawbacks.

Furthermore, in (3), there are safety and health problems due to the use of fluorescent substances, and in addition, in order to stop the copying operation, a detection means and a control mechanism for stopping it are required, and a special copying machine is required. Applicable only to machines.

In addition, any method completely prevents re-copying,
It is difficult to create a document that is fully visible, and although it is possible to prevent the document from being intentionally copied by making it impossible to re-copy, if the document itself is read, it will be difficult to create a document that is clearly visible. However, secrets are leaked.

(Object of the Invention) The present invention was made to solve the above-mentioned problems, and its purpose is to provide a method for easily creating confidential documents using an electrophotographic copying machine and diazo photosensitive paper. It is in. Another object of the present invention is to provide a method that completely prevents intentional influence of document contents. Still another object of the present invention is to provide a method for easily and clearly reproducing document contents using a diazo developing mechanism.

(Structure of the Invention) In order to achieve the above object, the present invention uses diazo photosensitive paper as a transfer paper, and forms a toner image corresponding to a first original image on the transfer paper using toner of the same color as the transfer paper. Transferring and fixing a toner image corresponding to the second original image onto the resulting copy using toner of a different color from that of the first image;
Furthermore, the first image is visualized by subjecting the copy to a diazo development step to develop color.

(Example) Examples of the present invention will be described in detail below.

The copying machine used in the present invention is a commonly used copying machine and does not have any special mechanism or control means, but the developing device contains toner of each color and is constructed to be replaceable. For this reason, it is desirable that the developing device be integrated into a unit. Furthermore, it is preferable to use a multi-color developing system copier which has two developing units in the copier and each unit is filled with toner of a desired color to produce any color depending on the copying purpose or original image. used.

When carrying out the copying method of the present invention, diazo photosensitive paper is used as the transfer paper, and a developing device containing toner of the same color (white or light yellow) as the diazo photosensitive paper is attached to the main body of the copying machine. Diazo photosensitive paper generally has a photosensitive layer made of a diazonium salt and a coupler formed on a base paper. When irradiated with high-energy light (ultraviolet light) such as from a mercury lamp, diazonium salt photodecomposes into phenol, but this photodecomposition product is colorless and does not become colored under the influence of light, heat, oxygen, etc. It is. When this diazo photosensitive paper is subjected to image exposure with high energy light through a light-transmitting original, the portion corresponding to the non-image area undergoes photodecomposition. On the other hand, since the portion of the diazo photosensitive paper corresponding to the original image is not irradiated with light, photodecomposition does not occur. Next, by adding this diazo photosensitive paper to a developer consisting of an alkaline solution, the diazonium salt causes a coupling reaction, and
Colored to form azo dyes. That is, only the portion corresponding to the information portion of the original image is colored, so that the original image is formed on the diazo photosensitive paper. In some diazo photosensitive papers, a one-component diazo photosensitive layer containing only a diazonium salt is developed with an alkaline solution containing a coupler. In addition, the development methods include wet development, which involves immersion in an alkaline solution,
There are semi-dry development methods that apply an alkaline solution, and dry development methods that involve exposure to ammonia gas.

The principle of creating confidential documents by using this diazo photosensitive paper as a transfer paper will be explained.

First, a first document (true information) is set on a document table and copied, and a white toner image corresponding to the document image is formed on diazo photosensitive paper used as transfer paper. The resulting copy has an image formed with white toner on white diazo photosensitive paper, making the image information portion difficult to decipher. This copy is further used as a transfer paper, a second original (dummy information) is set on the original table, and a copy is made using colored toner. A second layer formed with colored toner is placed on this transfer paper.
If a third party other than the information provider and recipient obtains this copy, unless they are very careful, they will only be able to read the information on the second manuscript, which is dummy information.

If the recipient wants to read the true information, he or she can simply feed this copy into a diazo developing mechanism. At this time, the exposure mechanism of the diazo copying machine is not necessary because it is not involved in the present invention, and only the developing mechanism is required. In a diazo copying machine in which the exposure mechanism and the development mechanism are integrated, it is sufficient to operate only the development mechanism without using the exposure mechanism. Although the diazo photosensitive paper used in the developing mechanism is exposed to normal light (visible light), it is not exposed to light (ultraviolet light) with high energy enough to cause photodecomposition. causes a coupling reaction and develops color. However, since the areas to which the white toner is attached do not come into contact with the developer, they do not react and do not develop color. Even if color develops, it will be covered up with white toner. Generally, many diazo photosensitive papers develop a blue color, so if the image of the second document is formed with blue toner, it becomes invisible to the naked eye together with the colored background. In other words, by applying it to the diazo developing mechanism, the easily visible image is reversed from the second information to the first information.

Since most of the ordinary diazo photosensitive papers are white, a white toner is essential in the method of the present invention, so the white toner will be explained below.

To prepare the white toner used in the present invention, a binder resin,
A white colorant and other compounding agents such as a charge control agent and a release agent are used, and the composition thereof is not particularly limited as long as it does not adversely affect the color tone of the toner. The ratio of the white colorant to the binder resin is generally 2:100 to 35:
It is preferable that the weight ratio be 100. If the weight ratio is less than this, the white toner will not be able to hide the background area, and if it is more than this, the triboelectric charging characteristics of the toner will deteriorate, and furthermore, spent toner will be likely to be generated, so that it cannot be used as a developer. lifespan becomes shorter.

As the binder resin used in this toner, various resin materials conventionally known as toner binder resins for electrophotography are used. For example, polystyrene, polystyrene
Styrenic copolymers such as butadiene copolymers, styrene-acrylic copolymers, ethylene copolymers such as polyethylene, polyethylene-vinyl acetate copolymers, polyethylene-vinyl alcohol copolymers, phenolic resins, epoxy-based resin, allyl phthalate resin, polyamide resin, polyester resin, maleic acid resin, etc.

The white coloring agents used in this toner include zinc white,
Examples include titanium oxide, tin oxide, antimony white, zinc sulfide, zinc oxide, barium carbonate, clay, silica, white carbon, talc, alumina, pallite, and the like.

As the charge control agent used in this toner, a known colorless or white one is used as it does not adversely affect the color tone of the white toner. For the purpose of positive charge control, organic compounds having basic nitrogen atoms, such as basic dyes, aminopyrine, pyrimidine compounds, polynuclear polyamine compounds, aminosilanes, or fillers surface-treated with these, are used. For the purpose of controlling negative charge, a carboxyl group-containing compound such as a metal chelate of alkyl salicylic acid is used. These charge control agents are preferably used in an amount of 1 to 10% by weight per toner.

Furthermore, examples of the release agent used in this toner include silicone oil, low molecular weight olefin resins, and various waxes.

The white toner is obtained by melt-kneading the above components, cooling them, and then crushing and classifying the mixture. It can also be obtained by dispersing toner ingredients in a resin solution and then spray granulating the resultant.

Diazo photosensitive paper has a slight yellow tinge, but since most of the binder resins used in white toner have a yellow tinge, the color can be adjusted simply by changing the amount of white colorant added. Ru. Furthermore, even if a yellow pigment such as titanium yellow is appropriately added, it is possible to obtain a toner having the same color as diazo.

Also, diazo paper that develops various colors has been developed, and when forming a toner image corresponding to the second original, it is best to use a paper that matches the color of the diazo paper that develops color. good.

(Effects of the Invention) As explained above, according to the present invention, true information is copied using toner of the same color as the diazo photosensitive paper, and dummy information is further copied thereon using toner of the same color as the diazo photosensitive paper. This makes it possible to create a confidentiality document and visualize the true information by applying it to a diazo developing mechanism when you want to obtain the true information. As a result, even if a third party other than the information provider and recipient obtains this information, only the dummy information will be read, thereby preventing the true information from leaking. Furthermore, even if this copy is made intentionally, true information can be transmitted.

Kasuri Xie Dermatoma Nita Kogyo Co., Ltd. Including

Claims (1)

[Claims] Using diazo photosensitive paper as a transfer paper, a toner image corresponding to the first original image is transferred onto the transfer paper with toner of the same color as the transfer paper, and the first image is Transferring and fixing a toner image corresponding to the second original image using toner of a different color, and further subjecting the copy to a diazo development process to develop color, thereby visualizing the first image. A copying method characterized by: