JPS608879A - Preventing device against copying of secret document - Google Patents

Abstract

PURPOSE:To reduce detection errors beyond the operation range of a detector by providing a mechanism which detects metallic layers and generates a warning so as to prevent the original sandwiched between the metallic layer from being copied. CONSTITUTION:The original 4 sandwiched between the metallic layers is placed on platen glass 6 and a metallic part 7 for checking operation is arranged in a cover 5 so as to set the distance d1+d2 to the original 4 below specific distance so as to detect the metallic layers effectively by a proximity detector 8. The proximity sensor 8 detects the original 4 for copy prevention having the metallic layer, and signals of transmitting, detecting, and Schmitt circuits 8a, 8b, and 8c vary from A to D; when the difference between a metal detection time and a reference time is detected, a warning device 11 warns that. Thus, the copying of a secret document is prevented, and a mix-up with other faults in the warning is prevented, thereby preventing an illegal copy from being taken with a spacer on the glass 6.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a confidential document copy prevention device.

More specifically, this invention provides a confidential document copying method in which a sheet for confidential documents that is not desirable to be copied is treated with metal in advance, and when metal is detected, a control system is activated to prevent the documents from being copied. Regarding prevention devices.

With the proliferation of prior art office copiers and 7mm 7mm, it has become highly desirable to provide a practical means to prevent unauthorized copying of confidential documents or copyrighted records. Ta.

Several methods have already been proposed to solve this problem, one of which is published in U.S. Pat. No. 3,597,0132.
It is shown. This is a photochromic material that, when copied, temporarily changes color to substantially match the color of the image that is not to be copied, thereby preventing the creation of a clear copy. Another method is to print records that are not to be reproduced on a notebook with a special masking background using a special ink that has a certain spectral range. Below, the recording is reflective and therefore invisible to the copier, but distinguishable from masking background forces in other spectral regions, and this property is exploited to prevent copying. These two methods prevent copying in some types of copiers, but this method uses so-called white-single-layer ght copiers that use photosensitive paper coated with zinc oxide.
It is not possible to prevent copying by. Additionally, the above method requires that the image be printed or written in precisely selected colors.

Purpose of the Invention Accordingly, it has been desired to develop a device that is not significantly affected by the color of the image and can prevent copying by all types of electrostatic copying machines including daylight copying machines and facsimile machines. It is an object of the present invention to provide an improved device that can reduce detection errors, especially when the detector is out of its operating range.

Structure of the Invention In conventional devices for detecting and controlling confidential documents, the sensitivity of the proximity sensor is limited to about 10 meters from the top of the platen glass due to space constraints within the copying machine, and the original is placed on the platen glass. If the distance is more than 10 m from the surface, the detection becomes I-IT function, and depending on the copying machine, it is possible to distinguish the copy of the original from about 30 m away from the platen glass. There was a problem in that if the documents were separated by about 30 cents, the purpose of the confidential document copy prevention device could not be achieved.

In order to avoid such problems, the present invention has been developed to incorporate metal into the document sheet by vapor deposition, coating, impregnation, bonding, etc. means for detecting the metal in accordance with the scanning process of the detection means, and for preventing the copying operation or copying contents when the metal is detected by the detection means or when a document is placed outside the operating range of the detection means. The copying machine is provided with means for starting a control operation to make the information unreadable or distinguishable.

The metal detection means used in the device of the present invention is a proximity sensor, which can detect any metal without contact by using the impedance change of the oscillation coil of the high-frequency oscillation circuit due to eddy current loss. etc. are well known, so a detailed explanation will be omitted here.

Further, the braking action starting means is means such as stopping a copying machine, a facsimile machine, etc. and/or generating an alarm;
Control operations are initiated when metal is detected during document sorting.

In the present invention, the document notebook is preferably entirely metal-treated to ensure protection against copying.

Metals used in the present invention include aluminum, iron, brass, stainless steel, and the like.

The copy-preventing document sort used in the present invention most commonly has a three-layer structure, as shown in FIG. 1, in which two sheets 1 are sandwiched with a metal thin film layer or four vapor-deposited layers 2 of gold.

The sheet 1 is a sheet of high-quality paper, pure white roll paper, plastic film, etc., and during this sorting, a metal thin film or vapor deposition layer 2 is provided by means of adhesive, adhesive, vapor deposition, etc.

As shown in FIG. 2, another manuscript notebook for preventing copying is also used, which has a 21-car structure in which a thin gold JVA layer or a metal vapor deposition layer is provided on only one side of the sheet 1.

Next, embodiments of the present invention will be explained based on the drawings.

Embodiment The confidential document copy prevention device of the present invention, as shown in one example in FIG.
It consists of a metal part 7 for checking the operation arranged inside the machine and a device 11 for displaying and informing that copying is not possible.

The fourth part is a circuit block diagram of the proximity sensor section, control section, etc. of the device shown in Figure 3. The operation of this device will be explained with reference to the flowchart shown in FIG.

Mass, Oherator transfers the original 4 to the platen glass 6 of the copying machine.
and set the start print switch 10 to "O".
When set to ``N'', only the scanning mechanism of the ill: f sensor 8 of the 31st node 1 operates, and the original surface detection is performed.
The detection distance when detecting aluminum foil is approximately 18 points.

If the distance from the detection surface of the proximity sensor 8 to the top surface of the platen glass 6 is dl, and the distance from the top surface of the platen glass to the field 64 is d2, the thickness of the platen glass 6 is 5 thresholds, and the distance between the glass 6 and the sensor 8 is If it is 3-, then d1 is 8, and in order to detect a copy-preventing document with metal 1, it is necessary that d2≦18-8=10. For this purpose, the copying operation may be performed only when the platen door (-5) is closed so that d2≦10.

In this embodiment, a proximity sensor 8 is installed in the platen cuckoo 5.
By arranging the metal part 7E for operation check that can be detected by the camera, and by setting the shape of the metal part 7 to be sufficiently smaller than the document 4, the proximity sensor v8 can prevent copying when the platen cover is closed as shown in Figure 3. When an original is detected and the original is to be picked up [Fig. 5(c), (d)], the oscillation circuit 8a
, the detection circuit 8b and the seamit circuit 8C change the signals to A −+ B −+ C−+ l), and the signal 4 detection times Ty and Tz are set in advance according to the operation check withdrawal J and 4 part 7. The reference time Tx = 1'o (i.e., Ty in Figure 5(b))) To, T in (C) and (d)
z << To ], as shown in the flowchart of FIG. 6, displays a message such as "copy not possible" and stops the copying operation, thereby making it impossible to make a normal copy.

On the other hand, when a normal document is correctly placed on the platen glass, the gold stripe detection time is the reference time T, as shown in FIG. 5(a). It will match or be within the error range close to it, and the copy will be made using the normal copy mode.

Methods other than blocking copying operations with the apparatus of the present invention include:
Although the copying operation is carried out by turning off the emission turtle of the charge transfer corotron or turning off the exposure lamp, it is also possible to make the copied contents unreadable or distinguishable.

Further, the scanning mechanism of the proximity center t8 can also be used in common with an optical system scanning mechanism such as an exposure lamp.

Furthermore, in a type of copying machine ζ in which the original table (platen/glass) moves, the scanning mechanism of the proximity sensor 8 is not necessary.

Note that displays and warnings such as "copy not possible" are intended to avoid confusion with other failures, so they may be changed or removed as necessary.

In the embodiment described above, the open/closed state of the platen cover 5 is detected by the proximity detector 8 itself, but other position detecting means such as an optical sensor or a magnetic sensor may be used.

Effects of the Invention The confidential document copy prevention device according to the present invention can copy all kinds of sheet originals that do not have a metal layer (as in a normal copying machine), and can detect metal on the surface of the original. After the determination, the copying operation begins, so there is no wastage of paper, etc.; there is no need to confuse it with other malfunctions due to displays or warnings such as "copying not possible"; 14, the copying operation can be reliably prevented even if an unauthorized copy is made of a copy-preventing document. , the detection system and therefore the device can be manufactured at low cost.

[Brief explanation of the drawing]

FIGS. 1 and 2 are sectional views of copy-prevention document examples used in the present invention, FIGS. 3 and 7 are schematic diagrams of apparatus examples of the present invention, and FIG. 8A4 is a circuit diagram of the apparatus shown in FIG. 3. Block diagram, 5th
Figures (a), (b), (c) and (d) are signal waveform diagrams inside the proximity sensor, and Fig. 6 is a flowchart explaining the operation of the device of the present invention. Symbols in the figure: ■... Sheet: 2... Metal layer; 3... Copying device bottom; 4... Original; 5... Platen cover: 6... Platen glass; 7... Operation Check detection part; 8...
・Proximity detector; 8a... Oscillation circuit; 8b... Detection circuit; 8c... Seamit circuit; 8d... Power supply circuit and output circuit; 9... Control circuit S 10... Start print switch; 11... Display or notification device; 12.
...Exposure equipment; (3 others) Figure 1 Figure 2 @3 Figure 4 Leap (No. 5111 (a) (b. (C) (d)

Claims (1)

[Claims] A copying device that prevents the copying of a document having information on a support containing metal, when said metal is detected or when the document is placed outside the operating range of its detection means;
1. A confidential document copy prevention device characterized by comprising means for starting a control operation that prevents the Enotake operation or makes the copied content unreadable or distinguishable.