JPS63246245A - Formation of image - Google Patents

Abstract

PURPOSE:To enable secret papers prepared by using an electrophotographic copy machine and a black insulating paper containing no substance generating heat by absorption of light to be again judged, by a method wherein the preparation of a heat sensitive perforated plate is processed by using as a copy a reproduction obtained in a process that a black toner image corresponding to an original image is formed on a black insulating paper which does not contain substance generating heat by absorbing light, and a master is prepared on a heat sensitive perforated plate printing paper. CONSTITUTION:A black paper which is colored by a black coloring agent as a dye, or otherwise by a combination of pigments which do not generate heat by absorbing light is used. An image is copied by an first setting an original on an original-placing table, and a black toner image corresponding to an original image is formed on a black insulating paper. The image information part of an obtained copy becomes difficult to be interpreted. When a heat sensitive perforated plate is formed by taking this all black copy as an original, only an image part formed by a toner containing carbon is perforated, and a master corresponding to the original copy image is formed. When printing is carried out by using this master, only the perforated part is colored, and the original image is reproduced.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for creating a confidential document using an electrophotographic copying machine and black insulating paper, and for reading the confidential document using a stencil stamp I11.

(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 these 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 contents modified 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 when copying.
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 (
(Japanese Patent Publication No. 184967/1983).

However, according to method (1), the transfer paper itself is colored with at least one of dyes and pigments during or after the paper making process, which complicates the manufacturing process and makes the documents expensive. 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 sufficiently visible to the naked eye, and although it is possible to prevent the document from being digitized by making it impossible to re-copy, if the document itself is read, it is difficult to create a document that can be read with the naked eye. However, secrets are leaked.

(Purpose of the Invention) The present invention was made to solve the above-mentioned problems, and its purpose was to create a photocopy machine using an electrophotographic copying machine and black insulating paper that does not contain any substance that absorbs light and generates heat. The purpose of the present invention is to provide a method for re-identifying confidential documents. Another object of the present invention is to provide a method for completely preventing digitization in document contents.Another object of the present invention is to easily and clearly reproduce document contents by performing stencil printing. The purpose is to provide a method.

(Structure of the Invention) In order to achieve the above-mentioned object, the present invention uses an image forming method to produce a copy in which a black toner image corresponding to an original image is formed on a black insulating paper that does not contain a substance that absorbs light and generates heat. The method consists of the steps of creating a master on thermal stencil printing base paper by performing thermal stencil production processing as a manuscript, and performing stencil printing using the master to form a printed image corresponding to the original manuscript image. Featured.

The present invention further provides an image forming method in which a black toner image corresponding to a first original image is formed on a black insulating paper that does not contain a substance that absorbs light and generates heat, and then a second original image is added to the copy paper. A process of creating a master on a thermal stencil printing base paper by using a copy with a white to light color toner image formed thereon as an original and creating a master on a thermal stencil printing base paper. and forming a print image corresponding to the original image.

(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.

In addition, since the present invention is carried out using the commonly used black toner, the developing device may be designed as a unit so that it can be replaced with toner of other colors, or multiple developing devices may be used to accommodate toner of various colors. There is no need to use a copying machine with a built-in multicolor development system.

When performing the copying method of the present invention, black insulating paper is used as transfer paper. Black! ! The border paper is selected to be one that does not contain coloring pigments, mainly substances that absorb light and generate heat, such as carbon. Ordinary black paper contains carbon as a coloring agent for the purpose of improving color development and preventing static electricity, and as a result, the entire paper becomes conductive, making it unsuitable for electrostatic transfer copying machines. Furthermore, if carbon is contained, a heat-sensitive stencil, which will be described later, cannot be produced. Therefore, in the present invention, black paper colored with a dye-based black colorant or a black paper colored with a combination of pigments that absorb light and do not generate heat is used. Examples of the former include ordinary water-based ink,
The latter is formed, for example, by mixing three colors: cyan, magenta, and yellow.

The principle of creating a confidential document by using this black insulating paper as a transfer paper will be explained.

First, place the original on the original table and copy the image.
A black toner image corresponding to the original image is formed on black insulating paper used as transfer paper. The resulting copy has an image formed with black toner on black paper, making the image information portion difficult to decipher.

If a third party other than the information provider and the recipient obtains this copy, it will appear completely black and it will be difficult to read the original image unless one is very careful.

A method for reading the original original image from this completely black copy will be explained.

Using this copy as an original, a master is formed on heat-sensitive stencil printing paper. A heat-sensitive stencil is obtained by bringing a heat-sensitive stencil printing paper and an original into close contact with each other, and then irradiating electromagnetic waves including infrared rays from the base paper side. This is based on the principle that infrared rays are absorbed by the carbon-containing image area of the original, and as heat is accumulated in this area, the area of the base paper corresponding to the original melts, creating holes and forming a stencil. It is.

Since the black insulating paper does not contain any exothermic substances, the heat-sensitive stencil printing base paper will not be melted even if it is irradiated with infrared rays.

When a heat-sensitive stencil is created using this completely black copy as an original, only the image area formed with the toner containing carbon is perforated. In other words, a master corresponding to the original original image is created from completely black paper. When printing is performed using this master, only the perforated portions are colored and the original image is reproduced. This allows confidential information to be transmitted without being leaked.

In the present invention, after forming the first document (true information) on black insulating paper with black toner, an image of the second document (dummy information) is further formed with white toner or light-colored toner, thereby making it more effective. can be raised. If true information that should be kept confidential is formed on black paper using black toner, it will be difficult to decipher, but if dummy information is formed on top of that using white toner, it will be difficult for third parties other than the informant and recipient to When someone gets their hands on it, they only read the dummy information and it is impossible to read the true information.

In order to read true information from this copy, a heat-sensitive stencil can be created in exactly the same manner as described above. This document has a black toner image (true information) and a white toner image (dummy information) formed on black insulating paper, but by performing thermal stencil processing, only a portion of the black toner containing carbon is perforated. . This creates a master that corresponds to the true information.

(Effects of the Invention) As explained above, according to the present invention, a confidentiality document is created by copying an original image on black insulating paper with black toner, and when decoding information, the copy is used as an original and a thermal stencil plate is used. By creating a master on printing paper and printing, it became possible to visualize the image. This prevents the true information from being leaked even if a third party other than the donor and the recipient obtains this information. Moreover, even more effects can be obtained by forming an image corresponding to the original image using black toner on black insulating paper, and then forming dummy information using white or light-colored toner.

Furthermore, it is possible to prevent this copy from being placed several times.

Claims (2)

[Claims] (1) A master is created on thermal stencil printing base paper by performing thermal stencil creation processing using a copy of a black toner image corresponding to the original image formed on black insulating paper that does not contain substances that absorb light and generate heat as an original. and performing stencil printing using the master to form a printed image corresponding to the original document image. (2) A black toner image corresponding to the first original image is formed on a black insulating paper that does not contain any substance that absorbs light and generates heat, and then a white to light-colored toner image corresponding to the second original image is further formed on the copy paper. A step of creating a master on a heat-sensitive stencil printing base paper by performing a heat-sensitive stencil production process using the formed copy as a manuscript, and performing stencil printing using the master,
An image forming method comprising the steps of: forming a print image corresponding to an original first document image.