JP2921117B2 - How to create non-recopyable documents - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[Industrial applications]

The present invention relates to a method for creating a non-recopyable document such as a confidential document by an electrophotographic copying apparatus.

2. Description of the Related Art

2. Description of the Related Art Recently, various copying apparatuses have been marketed, and copying can be easily performed anywhere. Along with this, stepless duplication of confidential documents, copyrighted documents, etc. has become a problem,
The need to prevent it has increased. Traditionally, as a way to create non-copyable documents,
Several methods have been proposed, for example, the following methods are known. Method using colored paper This method is to create an original on paper colored with a color matching the wavelength at which the spectral sensitivity of the photoreceptor is weak, making it difficult to obtain electrostatic contrast between the image area and the non-image area. Prevent copying. In this method, the paper has a relatively dark sepia or brown color, and there is a disadvantage that a document created thereon is difficult to read. Further, at present, copying machines equipped with photoconductors having various spectral sensitivities are commercially available, and it is difficult for this method to prevent re-copying in all copying machines. Method using high-reflectance paper This is a method of creating an original on paper (gold paper, silver paper) with a high regular reflectance. If this original is to be copied by a normal copying machine, the regular reflection component Since the light is reflected in a different direction from the photoreceptor, it does not reach the photosensitive member, making it difficult to obtain an electrostatic contrast between the non-image portion and the image portion, thereby preventing copying. In this method, there is a problem that the cost is high due to the use of special processed paper, and the electrostatic copying machine cannot be used when preparing an original because the surface has a conductive layer. The present invention has been made to improve the above-described problems in the conventional technology. SUMMARY OF THE INVENTION It is an object of the present invention to provide a method of creating a non-recopyable document that can obtain a legible copy.

[Means for Solving the Problems]

The above object of the present invention can be achieved by using a non-recopyable document-forming toner having a volume resistance of 10 ¹⁰ Ω · cm or more and having a metallic luster. The non-copyable document creating toner used in the present invention has a volume resistance of 10 ¹⁰ Ω · cm or more and is made of toner particles having metallic luster. The non-recopyable document creation method of the present invention uses the above-described non-recopyable document creation toner to develop a photosensitive member on which an electrostatic latent image is formed, and forms the formed toner image on the toner particles. It is characterized in that an image is formed by transferring the image onto a colored carrier having a similar hue. Further, another non-recopyable document creation method of the present invention includes:
The background area and the image area of the photosensitive member on which the electrostatic latent image is formed have a chromatic or achromatic toner other than white and a charge polarity of the opposite polarity to that of the toner, respectively, and have a volume resistance of
The toner is developed by using toner composed of toner particles having a metallic luster of 10 ¹⁰ Ω · cm or more, and then transferred to a transfer member. The non-recopyable document creation toner according to the present invention uses a known binder resin such as an ordinary styrene resin, polyester resin, polyamide resin, epoxy resin, and the like. Add a powder with gloss, and if necessary, pigment, charge control agent, wax,
It is formed by adding an external additive and the like. In the present invention, as the powder having metallic luster, for example, metal powder or alloy powder of mica, nickel, copper, aluminum, brass or the like can be used. In that case,
It is preferable to use a toner having a golden or silver color with a strong metallic luster. The blending amount of the powder having metallic luster is not particularly limited and can be set as appropriate, but in the present invention, it is necessary to blend each component in such an amount that the volume resistance becomes 10 ¹⁰ Ωcm or more. It is.
If the volume resistance is lower than 10 ¹⁰ Ω · cm, the transfer of the developed image becomes poor, the image density is low, and the image cannot be read. It is also preferable to mix the toner image in such an amount that the regular reflectance of the surface of the toner image fixed by development becomes 50% or more. The average particle diameter of the toner in the present invention is smaller than 30 μm, and preferably in the range of 3 to 20 μm. In the present invention, the toner may have a microcapsule structure including core particles and a shell material covering the core particles. In that case, the powder with metallic luster is
It is mainly contained in the core particles. The core particles are formed by adding a powder having a metallic luster according to a desired color tone and luster, such as a metal powder, mica, and a pigment, to the above-described known binder resin. The outer shell material is formed using the same or different resin as the binder resin used for the core particles, and is formed by adding a charge control agent, wax, or the like as necessary. Also in the case of the microcapsule toner, the color tone is preferably gold or silver with strong metallic luster. Microencapsulation methods include interfacial polymerization, in s
Any commonly used method such as an ite polymerization method, a coacervation method, a fluidized bed method, and a spray drying method can be used. In the case of the microcapsule toner, the outer shell contains no or little conductive material such as powder having metallic luster, so that the toner can maintain high electric resistance. Therefore, it is possible to add a large amount of powder having a metallic luster to be added to the core particles, so that the effect of creating a non-recopyable document is further exhibited. The non-recopyable document-forming toner used in the present invention preferably has a regular reflectance of 50% or more on the surface of the toner image after fixing, since the copied image becomes very legible. In the present invention, it is preferable that fine particles of an organic compound or an inorganic compound be further attached to the surface of the toner particles in order to adjust the electric resistance of the toner to provide high resistance.
Specific examples include fine powders of organic polymers such as polystyrene, polymethyl methacrylate, nylon, and polyethylene, and metal oxides such as silica, alumina, and titania. The particle size of these fine particles is smaller than that of the toner particles, and for example, those having a particle size in the range of 0.01 to 3 μm are preferably used. The non-recopyable document creation toner used in the present invention is:
It may be used as a one-component developer without using a carrier,
Further, it may be used as a toner for a two-component developer using a carrier. In the present invention, in order to prepare a non-copyable document using the above toner, an image may be formed on a colored carrier by an ordinary method by a usual electrophotographic method and fixed. In this case, it is necessary to select a combination that is most legible and that is not legible when re-copied, for the color tone and the density of the background portion and the image portion. Therefore, it is necessary to form an image on a colored carrier having a hue close to that of the toner particles. As the color carrier becomes closer to the hue of the toner particles,
Since the contrast difference between the image part and the background part becomes smaller,
The effect of creating a non-copyable document is increased. The colored carrier is not particularly limited as long as it can be copied, such as colored paper and colored plastic. The color of the colored carrier needs to be adjusted according to the toner to be used, but light black, light red, and the like are optimal. Further, the colored carrier preferably has a lightness of 0 to 7. If the lightness is higher than the above range, that is, if the color becomes lighter, the contrast effect is lost and the re-copying function is not exhibited. Another method for producing a non-recopiable document using the toner for producing a non-recopiable document of the present invention is a method implemented by using a copying machine provided with at least two developing machines. That is, the background area and the image area of the photosensitive member on which the electrostatic latent image is formed are respectively chromatic or achromatic toners other than white and have a chargeability of a polarity opposite to that of the toner, and have a volume resistance of 10 ¹⁰ Developed using a toner composed of toner particles having a Ω · cm or more and having metallic luster, and then transferred to a transfer carrier. For example, first, the background area of the photosensitive member is developed with a chromatic or achromatic toner other than white, and then the undeveloped image area is developed with the above non-recopyable document creating toner. Alternatively, the background area is first developed with a non-recopyable document creation toner, and then the image area is developed with a chromatic or achromatic toner other than white. Any type of copying machine, toner color tone and the like can be used. As the development and transfer method, there can be used, for example, a two-pass development method for each hue alone, a transfer method using a development transfer medium for each color alone, and a one-pass development method for overlap development, and is not particularly limited. In the case of this method, it is necessary to select and use a chromatic or achromatic toner and a non-recopyable document creation toner having opposite charging polarities.
That is, since the development of the background area is a reversal development,
For example, when the charge polarity of the photosensitive member is-, the charge polarity of the chromatic or achromatic color toner is-, and the charge polarity of the non-recopyable document creation toner is +. When the charge polarity of the photosensitive member is +, the relationship is opposite to the above. In the case of performing reversal development, development may be performed by setting the development bias to a value close to the background portion potential. As the chromatic or achromatic toner, any chromatic or achromatic color may be used as long as it is a toner other than white. When these are used for the background area, those having a dark color tone are preferable. According to this method, it is possible to create a document that cannot be copied again even if the carrier is not colored. And, for example,
It is more preferable to form a gold image on a gray background and a blue image on a silver background.

【Example】

Hereinafter, the present invention will be described with reference to Examples and Comparative Examples. In addition, “parts” means parts by weight. Example 1 (Production of Toner) Example 1 (Toner A) Styrene-n-butyl methacrylate (7: 3) copolymer 73 parts Gold metal powder (brass powder) 25 parts Charge adjuster (Aizen Spiron Black TRH, Hodogaya 2 parts The above components were melt-kneaded, cooled, pulverized finely, and classified by a classifier to obtain a golden toner having an average particle diameter of 11 μm. The volume resistance of this toner was 10 ¹² Ω · cm. Example 2 (Toner B) Styrene-n-butyl methacrylate (7: 3) copolymer 73 parts Silver metal powder (aluminum powder) 25 parts Charge adjuster (Aizen Spiron Black TRH, Hodogaya Chemical Co., Ltd.) 2 parts And in the same manner as in Example 1, an average particle diameter of 11 μm.
m and a toner having a volume resistance of 10 ¹¹ Ω · cm. Example 3 (Toner C) Polypropylene resin (High Wax 400P, manufactured by Mitsui Petrochemical Co.) 30 parts Golden metal powder (brass powder) 50 parts The above components were kneaded with an extruder, pulverized and classified to obtain an average particle diameter of 10 μm. Colored particles were obtained. 80 parts of the above-mentioned colored particles 18 parts of a styrene-n-butyl methacrylate (7: 3) copolymer 18 parts of a charge control agent (Eizen Spiron Black TRH, manufactured by Hodogaya Chemical Co., Ltd.) 2 parts The above components are dissolved and dispersed in toluene, and a spray drier Microencapsulation with volume resistance of 10 ¹³
An Ω · cm capsule toner was obtained. Example 4 (Toner a) (Comparative Example) Styrene-n-butyl methacrylate (7: 3) copolymer 53 parts Gold metal powder (brass powder) 45 parts Charge adjuster (Aizen Spiron Black TRH, Hodogaya Chemical Co., Ltd.) 2 parts The above components were melt-kneaded, cooled, pulverized finely, and classified by a classifier to obtain a gold toner having an average particle diameter of 11 μm. The volume resistance of this toner was 10 ⁸ Ω · cm. Example 5 (Toner b) Styrene-n-butyl methacrylate (7: 3) copolymer 88 parts Carbon black (Black Pearls L, manufactured by Cabot) 10 parts Charge adjuster (Eizen Spiron Black TRH, manufactured by Hodogaya Chemical Co., Ltd.) 2 parts Using the above components, and in the same manner as in Example 1, 11 μm in average particle size
m and a toner having a volume resistance of 10 ¹⁴ Ω · cm. Example 6 (Toner c) (Comparative Example) Styrene-n-butyl methacrylate (7: 3) copolymer 90 parts Red pigment (Pigment Red 48: 1) 3 parts Yellow pigment (Pigment Yellow 97) 7 parts Using the above components In the same manner as in Example 1, the average particle size was 11 μm.
m and a toner having a volume resistance of 10 ¹⁴ Ω · cm. Copying Example 1 A developer was prepared by mixing 3 parts of the toner A and 100 parts of a carrier (for FX5030, manufactured by Fuji Xerox Co., Ltd.). Using this developer, an image was formed on gray paper (density 0.50, lightness 5) by a copying machine (FX5030, manufactured by Fuji Xerox Co., Ltd.). The regular reflectance of the surface of the obtained toner image was 76%. Using the copy obtained as described above, recopy was performed with a commercially available copy machine (FX5030, manufactured by Fuji Xerox Co., Ltd.). The results are shown in Table 1 below. In the same manner, copying was performed in the same manner as described above using each toner and colored paper, and re-copying was performed in the same manner using the obtained copy. Table 1 shows the results. Copying Example 2 In a first developing machine of a copying machine (FX5030, manufactured by Fuji Xerox Co., Ltd.), the developer prepared by using the toner A was charged, and the toner b was charged in a second developing machine. Use the marking color mode of the copier (FX5030) to set the background area to black (density
0.70), a golden copy was obtained in the image area. Table 2 shows the results. For comparison, a copy was obtained in the same manner as in the above-mentioned copy example except that a toner of sepia color having no metallic luster (toner c) was used instead of toner A. Using these copies, recopying was performed in the same manner as in the example using four copying machines. Table 2 shows the results. The copying machines used were FX5030 and FX5070 (manufactured by Fuji Xerox), NP4335 (manufactured by Canon), and FT4530
(Manufactured by Ricoh Company).

【The invention's effect】

The non-recopyable document obtained by the present invention is very legible because it is composed of a portion having metallic luster and a portion having no metallic luster. And if you want to re-copy the document,
Some of the light that hits the metallic luster is specularly reflected, so it does not enter the normal optical path of irregularly reflected components.
Some of the irradiation light does not reach the photoconductor. That is, the portion is determined to be gray, and there is no difference in contrast from other colored portions, so that recopying is impossible even if copying is performed by any copying machine. According to the method of the present invention, a non-recopyable document can be created at low cost without using special processed paper.

Claims (2)

(57) [Claims] 1. A photosensitive member on which an electrostatic latent image is formed is developed using toner composed of toner particles having a volume resistance of 10 ¹⁰ Ω · cm or more and having a metallic luster, and is close to the toner particles. A method for preparing a non-recopyable document, comprising forming an image by transferring the image on a colored carrier having a hue lightness of 0 to 7. 2. The image forming apparatus according to claim 1, wherein the background area and the image area of the photosensitive member on which the electrostatic latent image is formed have a chromatic or achromatic toner other than white and a charge polarity opposite to that of the toner. Developing using toner composed of toner particles having a metallic luster of 10 ¹⁰ Ω · cm or more, and then transferring the developed toner to a transfer member.