JPH0116098Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to an improvement in an electrophotographic transfer sheet containing a layer of metal or metal compound that can be detected by a proximity detector and can be used to create originals by any means such as copying. It is something. With the spread of office copy machines and fax machines,
It would be highly desirable to provide a practical means to prevent unauthorized copying of confidential documents or copyrighted records, and several methods have already been proposed. The present inventors also treat document sheets by vapor-depositing, coating, impregnating, pasting, etc. with metal, and also provide means to detect and respond to the metal in document sheets in accordance with the scanning exposure process during copying. proposed a new device. The present invention is an electrophotographic transfer device that can be used to prevent the copying of information once created by means such as copying or printing, in the confidential document copy prevention device previously proposed by the present inventors. The purpose is to improve the seat. Conventionally, aluminum-deposited paper for discharge recording, for example, is known as a metal-containing sheet.
This material has a base paper 1 as shown in the cross-sectional view in Figure 1.
A carbon layer 1b, an aluminum vapor-deposited layer 1c, and a white conductive layer 1d are provided on the layer a. Even if such a metal-containing sheet is passed through an electrophotographic copying machine to obtain a copy, the electric charge escapes due to its low electrical resistance, and therefore transfer cannot be performed, so it can be used as an electrophotographic transfer sheet. Things did not previously exist. In addition, the present inventors have already filed a patent application for an electrophotographic transfer sheet containing metal (Japanese Patent Application No. 146823/1982) (see Japanese Patent Application Laid-open No. 37551/1983), but the present invention is further This is an improved version of . The present invention is an electrophotographic transfer sheet that can be detected by a proximity detector, has sufficient paper passability for an electrophotographic copying machine, and can be used not only as printing paper but also as an electrophotographic transfer sheet, and can be used to create manuscripts by any means. It provides: When a sheet having the structure described in the earlier application is passed through a copying machine such as the product name Xerox, if the metal layer and the paper or plastic film sandwiching it are made thicker, the sheet becomes too stiff and jams occur in the copying machine. Something happened. Additionally, there were machines that caused transfer defects in high-humidity environments. This is because the metal thin film layer in the sheet is entirely conductive, making it difficult to transfer. The present invention was made based on the discovery that the above-mentioned problems can be improved by providing a discontinuous metal vapor deposition layer or metal thin film layer that can be detected by a proximity detector. be. That is, the structure of the sheet according to the present invention is, for example, as shown in FIG. 2, consisting of three layers of paper or plastic films 2a and 2c sandwiching a discontinuous metal vapor deposition layer or metal thin film layer 2b in a sandwich shape. . As described above, by providing a discontinuous metal vapor deposition layer or metal thin film layer, it becomes difficult for electricity to flow through the metal-containing sheet, making it possible to prevent transfer defects in high humidity environments. be. Polyvinyl alcohol (PVA), cellulose resin, which is commonly used as an adhesive to bond paper and metal-deposited paper or paper and metal thin film,
Examples include polyvinylpyrrolidone, acrylic resin emulsion, polyethylene resin emulsion, synthetic rubber latex, acrylic acid ester copolymer, polyethylene, polypropylene, and ionomer. The thickness of the metal thin film layer is not particularly limited, but it is preferably not too thick in terms of paper passing through copying machines such as Xerox (product name), and is usually 30 μm.
The following are preferred. On the other hand, the thickness of the metal vapor deposited layer is preferably 2000 Å or more in order to maintain an appropriate detection distance by the metal sensor. Further, the thickness of the paper or plastic film layer is preferably more than 10μ, and although there is no particular upper limit, it is preferably not too thick, and usually 100μ or less is used. Metals or metal compound metals that can be detected by the proximity detector that can be used in the present invention include aluminum, iron, copper, zinc, cadmium, silver, and nickel, but aluminum or iron is most preferred from the viewpoint of manufacturing. The apparatus using the sheet of the present invention comprises a proximity detector 6 arranged so as to be able to detect the metal layer of the original sheet 3 through the platen glass 5, as schematically shown in FIG. 4 indicates a platen. The proximity detector is capable of detecting any metal in a non-contact state by utilizing the change in impedance of the oscillation coil of the high frequency oscillation circuit due to overcurrent loss, and its internal structure is well known and will not be described in detail. Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples. Example 1 After applying a mold release agent to a 12μ thick polyester film, Al was deposited to a deposition thickness of 2800 Å.
An ethylene vinyl acetate copolymer heat-sensitive adhesive was applied to this vapor-deposited layer. The vapor deposited layer of such a film has a basis weight of 43g/
Partially transferred using a mold onto ² m2 high-quality paper, and the 4th
A partially vapor deposited paper having a unit vapor deposition area of 10 mm x 10 mm as shown in the figure was obtained. Furthermore, this vapor deposition surface and other basis weights 43
g/m ² of high quality paper using an acrylic adhesive. Example 2 Using the same vapor-deposited film as in Example 1, a basis weight of 43
A partially vaporized paper as shown in FIG. 5 was obtained which was partially transferred to a high quality paper of g/m ² . Furthermore, this vapor deposition surface and other basis weights 43
g/m ² of high quality paper using an acrylic adhesive. Comparative Example 1 A high-quality paper with a basis weight of 43 g/m ² was coated with 6 g/m ² of polyvinyl alcohol, and then Al was deposited to a thickness of 2900 Å. Furthermore, this vapor deposition surface and the basis weight of 43g/
m ² of high-quality paper was bonded using an acrylic adhesive. Comparative Example 2 After applying 6 g/m ² of polyvinyl alcohol to a high-quality paper with a basis weight of 43 g/m ² , Al was vapor-deposited to a thickness of 1300 Å. Furthermore, this vapor deposition surface and the basis weight of 43g/
m ² of high-quality paper was bonded using an acrylic adhesive. The test data of electrophotographic copying machine copyability and copying machine runnability of the sheets obtained in Examples 1 and 2 and Comparative Examples 1 and 2 are shown in the following table. 【table】

○: Good △: Usable ×: Unusable

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of a conventional aluminum vapor-deposited paper for discharge recording, Fig. 2 is a cross-sectional view of an example of a metal-containing transfer sheet for electrophotography according to the present invention, and Fig. 3 is a side view of a device using the sheet of the present invention. A cross-sectional view, FIG. 4 is a perspective view illustrating the shape of the discontinuous metal deposited layer of the sheet of the present invention, and FIG. 5 is another embodiment of the sheet of the present invention.
FIG. 2 is a perspective view illustrating the shape of a partially vapor-deposited metal layer. In the figure, 1a...Base paper, 1b...Carbon layer, 1c
...Aluminum vapor deposited layer, 1d...White conductive layer, 2a,
2c... Paper, 2b... Metal layer, 3... Original sheet, 4... Platen, 5... Platen glass, 6
...Proximity detector.

Claims (1)

[Scope of utility model registration request] 1. A metal-containing transfer sheet for electrophotography, characterized in that plastic film or paper is laminated in a sandwich-like manner on both sides of a discontinuous metal vapor deposited layer or metal thin film layer that can be detected by a proximity detector.