JPS59135451A - Method for preventing confidential document from copy - Google Patents

Abstract

PURPOSE:To make a part of the copying operation, at least, unoperated or stop it, by allowing a fluorescent substance, which emits light for irradiation light, to exist in a part of a document at least and allowing the fluorescent substance to emit light when it is irradiated with light and detecting this emitted light by a detecting means. CONSTITUTION:Before the copying operation, an original to be copied is set on a contact glass 19. Though this original is scanned for exposure by an exposure optical system, infrared rays of a halogen lamp 21 are irradiated to the original through a reflector 20 before the original is illuminated for scanning by the halogen lamp 21. If the original is a confidential document 27, fluorescent substances 29 emit visible rays for infrared rays because the document 27 includes fluorescent substances 29, and visible rays are detected by a photodetector 30 to detect that the original is the confidential document 27 whose copying is inhibited. All copying operations including the electrifying process, the exposure process, etc. are made unoperated by the detection signal due to the photodetector 30, thereby preventing the confidential document from being copied.

Description

[Detailed description of the invention] Technical field The present invention relates to a confidential document copy prevention method.

BACKGROUND ART In recent years, there has been a significant increase in information, and there is a need for rapid transmission of that information to many people in many directions, and copying devices such as electrophotographic copying machines and transmission records such as facsimiles are used to easily reproduce documents. The device is widely available. Coupled with this widespread use, the amount of information continues to increase,
On the other hand, confidential information such as new product planning materials, market research materials, confidential diplomatic materials, military materials, etc. can be copied extremely easily, making it difficult to maintain the confidentiality of confidential image information. There is.

Therefore, methods have been proposed to prevent confidential documents containing confidential image information from being duplicated by a copying machine or the like. For example, by drawing the confidential image information itself with fluorescent material, even if a copy operation is performed on this document, the confidential image area will also emit light during the exposure process, so that the image area and non-image area will be printed on the photoreceptor. There is a method that forms an image so that it can be clearly distinguished from the image area, that is, it does not form a latent image as in the case of a blank document. In addition, as a method using the same principle, a fluorescent substance is coated on the entire surface of a confidential document to prevent the formation of a latent image on the photoreceptor, or a confidential document is coated on the surface of a metal foil with an extremely smooth surface. Various proposals have been made, including ones that prevent latent image formation by carrying image information. In other words, in these conventional methods, when an image is formed on a photoreceptor in the exposure process in a duplication operation, the difference between the image area and the non-image area is minimized as much as possible, whereas the document is treated as a blank original. It uses the technical means of identification. However, in general, in order to faithfully reproduce visible information, the sensitivity characteristics of a photoreceptor are designed to be as similar as possible to those of the human eye. Therefore, in the case of a confidential document whose copy has been made completely unreadable in the conventional method, the confidential document itself is difficult to read (even though it is a confidential document, the readability of the confidential image information is not good). On the other hand, if the "4" resistance of this confidential document is improved, the resulting copy will have poor contrast but will be unreadable. stomach.

Accordingly, the present applicant has provided a fluorescent substance that emits light at a wavelength different from the wavelength of the excitation light to excitation light in at least a part of the document carrying confidential image information, and the excitation light is applied to the document. Luminescence 'f' from a fluorescent substance that is irradiated and receives this excitation light: A stake that is detected by a detection means and that at least a part of the replication operation is inverted or stopped by the detection signal to make replication impossible. Methods for preventing copying of secret documents have already been proposed. In this case, various fluorescent substances have been mentioned, but some of these are expensive and others require a lot of effort to manufacture.

Purpose The present invention has been made in view of the above points, and while it is a confidential document that has confidential image information that is easy to read like a normal document, it is possible to completely prevent D production from the confidential document and improve confidentiality. The purpose of the present invention is to provide an inexpensive and reliable method for preventing copying of confidential documents that can ensure the security of confidential documents.

Configuration (First Embodiment) A first embodiment of the present invention will be described based on FIGS. 1 to 3. This embodiment relates to copy prevention in an electrophotographic copying machine, and an outline of the apparatus is shown in FIG. First, around the photoreceptor drum (1), there is a charger (2) that uniformly charges the surface of the photoreceptor drum (1) according to the Carlson method, which is a general process, and an exposure optical system that forms and irradiates image information. (3), a developing device (4) that applies developer to the latent image and develops it, a cassette (5), a paper feeding roller (6), and a transfer paper (8) fed by a registration roller (7); A charger (9) that transfers a developed image to a transfer sheet (8) that is separated from the photoreceptor drum (1) by a separation charger 00) and a separation claw αη and conveyed by a conveyor belt α2. A fixing device 09, an IJ cleaning device α4, and a static elimination lamp α9 are provided, and a paper discharge roller O is provided outside the fixing device 01.
G, paper output tray 0 force is provided. In addition, documents such as manuscripts are placed on the top of the copier body! Pressure plate (18
) There is a contact crow covered by 0 steals. Then, the exposure optical system (3) beam flap (E)
The halogen lamp (21) surrounded by the first mirror (
C), the second mirror (C), the in-mirror lens (2→, the integrated norogen lamp Q1) and the first mirror Q→ face the contact glass α9). It moves from right to left while exposing, and the second mirror (c) also moves from right to left at 1/2 the speed.

The halogen lamp (C) is a light source that emits infrared light, which is visible light or long wavelength light, and the reflector is a cold mirror so that only the infrared light is emitted diagonally upward in the scanning direction. A light shielding plate QQ is further added between the contact glass 09). On the other hand, the confidential document (c) has confidential image information that is easily readable like a normal document, but the surface of the confidential document (c) has a spot-shaped fluorescent material (as shown in FIG. 3(a)). 29tL), or striped fluorescent material (2 leeches) as shown in the same figure (clause), or coated with a striped fluorescent material (29G) as shown in the same figure (0). (However, these are just examples, and the presence of the fluorescent substance (c) is arbitrary. It may be present in the form of one spot or one in the form of a stripe. at least in some parts).

Here, as the fluorescent substance (c), a substance having a stimulation effect by long wavelength light such as infrared light is used. Some fluorescent substances absorb light and emit light for a long time after entering an excited state, and if they are irradiated with long-wavelength light such as infrared light while emitting light, they rapidly emit light. However, some exhibit a phenomenon of bright light emission, and this phenomenon is called the photostimulation effect. Substances that have such a photostimizing effect include CaS: Bi, β
Ihi such as ZnS:Cu, ZnS:CuCo, etc.

It is known that compounds, oxides, or barium fufluorochloride are relatively easily available and inexpensive materials.

Therefore, fluorescent material applied to confidential documents (company)■9
) A device that emits visible light (emit phosphorescence due to phosphorescence) using the infrared light of the halogen lamp (a) irradiated through the beam flap (a), and a detection means for detecting this visible light. A light receiver (a) is provided as a.

This receiver 00) is equipped with a halogen lamp Qυ, a first mirror (
C), which can be integrated into and move, such as Q, CdS photocells, phototubes, Si photodiodes, Ge detection elements, etc. Here, tt is sufficient for CdS photocells, phototubes, etc. whose sensitivity is almost in the visible light range, but tt is sufficient for devices such as CdS photocells and phototubes, but K
'ri] Those that are sensitive to visible light to infrared light,
In order to prevent malfunction, an infrared light cut filter 0→ is provided on the front surface. This infrared light cut filter (3)
), a multilayer film is deposited on a glass substrate to transmit visible light and reflect infrared light, or a material in which metal ions are placed in glass to absorb infrared light. Ru.

Prior to the copying operation, the original sheet to be copied is set on the contact glass (19). Then, this document is exposed and scanned by the exposure optical system (3), but from the positional relationship shown in Fig.
Before the document is scanned and illuminated by υ, the document is irradiated with infrared light from this halogen lamp Qll) via the reflector (a). At this time, if the document is a confidential document (x7), it has a fluorescent substance &I, so this fluorescent substance (29) receives infrared light and emits visible light, and this visible light is transmitted to the light receiver (
It is detected that the document is a confidential document (b) that must not be copied.

Therefore, due to the detection signal from this photoreceiver (g),
By making all copying operations such as the charging process and the exposure process indestructible, the confidential document (a) will not be copied. On the other hand, if the document is a normal document, it does not have a fluorescent substance, so even if it receives infrared light, the document does not emit visible light and is not detected by the light receiver C301 (at this time,
Even if it is a Si photodiode or the like, there is no false detection due to the infrared light cut filter t3]), so the replication operation is performed as usual and drug a is obtained.

Here, since the light receiver (g) is set to act temporally before the band'd-c step, it will be activated from the first step of the duplication operation by detecting visible light, making duplication impossible. However, it is also related to the method of creating the presence of the fluorescent substance e9).At the same time as the scanning illumination of the original by the Ajino-Rogen lamp 0υ, infrared light from the No-Rogen lamp H is also irradiated, and the exposure If it is a confidential document (a) during the process, the presence of the fluorescent substance, and therefore the visible light emission thereof, may be detected by the light receiver 00. In this case, since a part of the duplication operation has already started, for example, the entire surface of the photoreceptor drum (1) is exposed based on the detection signal to erase the latent image formed so far. To erase or
Supply of developer to the photoreceptor drum (1) and transfer paper (8)
) At least a part of the replication operations essential for replication, such as stopping the supply of . This results in no copies being obtained. Basically, it is sufficient to stop the subsequent copying operation based on the detection signal from the photoreceptor (G), but the rotation of the photoreceptor drum (1) may be stopped for maintenance of the device, etc. First, as described above, it is preferable to make duplication impossible by, for example, stopping the developer supply. It may also be in an inverted state due to a change in transfer voltage or the like. in short,
In the present invention, the term "copying operation" refers to an operation performed in the copying device that is essential for obtaining a normal copy, and 1- "immobilizing or stopping the copying operation" refers to an operation performed in the copying device that is essential for obtaining a normal copy. It means to create a state in which Jl is not obtained.

By the way, in the case of the fluorescent substance C9) having a photostimulating effect in this example, it is necessary to bring it into an excited state before irradiating it with long wavelength light such as infrared light. In this regard, since the confidential document (b) is normally exposed to natural light before it is copied, it will be excited, but in order to increase certainty and guarantee the excited state, as shown in Figure 2, Prior to infrared light irradiation, the confidential document (c) may be pre-exposed to ultraviolet light or other short wavelength light that excites the fluorescent substance (c) using an excitation light source (excitation light source). Here, suitable excitation light sources include a black light that emits ultraviolet rays, a fluorescent lamp that includes an excitation light wavelength, and a tungsten lamp that has a relatively high color temperature.

Therefore, according to this embodiment, even the confidential document Q'i') is no different from a normal document, and the readability of the confidential image information (c) is good and the presence of fluorescent substance 09). is not visible), and during the copying operation it is classified as a confidential document (
If it is a document), due to the presence of a fluorescent substance (b), the fluorescent □ light is detected by the photoreceptor □□□, and it is distinguished from a normal document.
This detection signal causes at least a portion of the replication operation to remain stationary or stop, so it is possible to make replication impossible without letting the operator know the cause, and it is possible to ensure the confidentiality of the replication.

Furthermore, since a substance having a photostimizing effect is used as the fluorescent substance (c), it is easily available and inexpensive. Furthermore, since phosphorescence from a fluorescent material emitted by the photostimulation effect upon irradiation with infrared light is detected, the energy is large, the detection accuracy is high, and the device is also simplified.

Note that a tungsten lamp may be used instead of the halogen lamp Qυ as a light source that emits visible light or infrared light. In addition, as shown in Fig. 4, only a part of the reflector (A) is made into a cold mirror part (20a), and this cold mirror part (20a) is used as a mirror (32) to emit long-wavelength light through the lens 03. VC may be used to irradiate external light. @ is a light shielding plate. Either method shown in Fig. 4 or Fig. 2 can be used without impairing the document illumination effect of the original visible light of the halogen lamp Q1). , which contributes to the detection of fluorescent substances.

In addition, in Fig. 1, the person's position is the home position of the first mirror (2), etc., but the home position is on the B position ' side, and by scanning from the B position to the person's position, the g light substance (2
Scanning may be performed to detect the presence or absence of 9), and if the confidential text is not Q, exposure scanning of the document may be performed during the return operation from this person's position to position B.

(Third Embodiment) Next, a second embodiment of the present invention will be described with reference to FIGS. 5 to 8. The same parts as those shown in the previous embodiment are given the same reference numerals, and the explanation will be omitted.

In contrast to the above-mentioned embodiment in which a fluorocarbon lamp (GL) is used in common for detecting a fluorescent substance 09), this embodiment uses an independent light source 09 as a detection unit 00 and integrates it with a light receiver (A). A detection section array is installed, and the first Mira Q
It is designed to move integrally with 2@-.

Here, the light source 09 is a red light emitting LE for infrared light.
D, infrared emission Ll), etc. are used. However, even a tungsten lamp or the like can be used in conjunction with a visible light tunot filter.

(Third Embodiment) A third embodiment of the present invention will be explained with reference to FIGS. 9 to 11. This embodiment uses a light transmission member 0→09 made of molded plastic (transmissive material such as PMMA, polycarbonate, etc.) or polished glass, and the light source (40 )
θη causes infrared light to be transmitted to the document from the emission surface (38α) and irradiated onto the document, and if a fluorescent substance Q→ is present, the visible light is transmitted from the incident surface (39θ) to the light transmission member 09). The light is guided to the light receivers (6) (13) at both ends for detection.

In this case as well, if the light receiving device 1'3 is sensitive to infrared radiation, an infrared light cut filter may be added to prevent malfunction. In addition, the light transmission member 090
9, its emission surface (38α) and incidence surface (39a)
AJ on the side excluding ? , A? It is also possible to form a thin film layer using a method such as a vacuum evaporation method or a sputtering method to improve reflection efficiency and use efficiency of detection light. The cross-sectional shape of the light transmitting member is not limited to a triangular light transmitting member, but may be an abbreviated light transmitting member n4)ue as shown in FIG. In the end, the one with the most efficient illumination and light reception is selected depending on the distance 1rj arranged with respect to the original, and in particular, the emitting surface (38α) may be a ground glass-like diffusing surface.

(Fourth embodiment) Next, FIGS. 13 and 14 show the fourth embodiment 7 of the present invention.
/flj example, where the optical fiber bundle (4*Q'
I)'e is used. □In other words, the optical fiber bundle 000 is made by binding and bonding optical fibers made of glass, plastic, etc., and the optical fiber bundle 00 has one end tied to the size of the light source 0→ that emits infrared light, and the other end The infrared light from the light source 013 is irradiated onto the original through the optical fiber bundle 0, and the light receiver (1g ) to detect the presence or absence of a fluorescent substance (c), that is, the presence or absence of visible light.

(Fifth Embodiment) A fifth embodiment of the present invention will be described with reference to FIG. 15. In this embodiment, Q fluorescent substances are coated on the back side of a confidential document (a), and a detection unit (7) detects the presence of these fluorescent substances.
It is arranged at an arbitrary location on the total pressure plate aυ. Here, the detection section (7) is similar to the detection section 6φ of the second embodiment. At this time, it is preferable to use a light emitting/receiving section with as small an opening area as possible in order to reduce the influence of the copy image being skimmed. Moreover, although it is preferable to apply the fluorescent substance (c) to the entire surface, it may be applied only to a predetermined position corresponding to the detection part OQ.

(Sixth Embodiment) Furthermore, a sixth embodiment of the present invention will be described with reference to FIG. 16. This embodiment is applied to a copying machine equipped with an automatic document feeder (51). First, to explain the entire process, the document G → set on the document table G group is fed one by one by the paper feed roller and separation roller 6υ, then the turn roller 6, the pinch roller, and then the conveyor belt. is conveyed onto the contact glass θ9) and set in a predetermined position by the stop claw 05, and when exposure scanning is completed and the copying is completed, the stop claw line is retracted and the conveyor belt (A) and the conveyor roller 9) ) Ray (is discharged at 6υ).

In order to detect the presence or absence of a fluorescent substance (9) between the paper feed roller (4) and the turn roller (4), a detection unit (6) is placed opposite the upper surface (front surface) of the passing document (9).
Seconds are set. This detection part O is similar to the detection part OQ, etc. If the document passing through is a confidential document (company), there is a fluorescent substance (c), so it detects visible light based on infrared light irradiation. When it receives light emission, it detects it and stops the duplication operation until the end. In particular, since the detection is performed before setting on the contact glass (19), all copying operations such as the exposure process can be stopped to prevent paper products from being produced. In the case of this embodiment, it is also effective to coat the back side of the confidential document Q with a fluorescent substance ←9 and to provide the detection units (six) facing each other on the bottom side as shown by the dashed line.

(Seventh Embodiment) A seventh embodiment of the present invention will now be described with reference to FIG. 17. This embodiment is applied to a facsimile machine. First, to explain its outline, the original (goods) for transmission set on the original table (j) is moved by the original transport roller (
:) υ, separation roller M, separation plate (671) feed one sheet at a time, and while it is transported at a predetermined speed over the contact glass q* by the front and rear reading and transport rollers (layer taS), the light source (
7]), the reflected light is reflected from the mirror (7■
, is read by the image sensor C→ via the lens system Q, and the signal is transmitted to the receiving side and recorded. (70 is a document tray. Note that a description of the receiving system will be omitted.

In order to detect the presence or absence of a fluorescent substance (c) between the plow of the document conveyance roller and the ring of the separation roller, a detection unit V0 is placed facing the lower surface (original 111) of the fed document (original 111). Due to space issues, it is preferable to use an optical fiber bundle as in the fourth embodiment for this detection unit (7), but in any case, if the source 1-1 passing through is classified If it is a document type), the fluorescent substance is present, so it receives visible light emission based on infrared light irradiation and detects it, and the illumination by the light source (7), which is one of the duplication operations, stops. As a result, nothing is read by the image sensor →, and in the end, no reception is recorded on the receiving side.Also, even if paper feeding to the installed conveyance roller (6 side) is stopped, good.

It should be noted that the present invention is not limited to these embodiments, but can be similarly applied to diazo type copying machines, copying machines of a document table moving type, and the like.

Effects As described above, the present invention provides a fluorescent material that emits light in response to irradiation light in at least a part of a document carrying confidential image information, and irradiates the document with irradiation light so that if the document is a confidential document, the fluorescent material is emitted. Because the optical substance emits light when it receives the irradiation light, it is detected by the detection means, and the basic operation of stopping at least a part of the copying operation allows the turrets and secret documents themselves to remain unchanged from ordinary documents. It is highly legible and the presence of fluorescent substances is not visible, making it possible to reliably prevent the acquisition of copies and ensure confidentiality.
In this case, since a substance with a photostimulating effect is used as the fluorescent substance, the wooden sword type is easily available, inexpensive, simple, and can be realized reliably.

[Brief explanation of drawings]

FIG. 1 is a schematic side view showing a first embodiment of the present invention, and FIG.
The figure is a side view showing an enlarged view of the main parts, and Figures 3 (α) to (
o) is an explanatory diagram showing an example of the arrangement of fluorescent substances, FIG. 4 is a side view showing a modified example, FIG. 5 is a side view showing a second embodiment of the present invention, and FIG. 6 is a partial view thereof. A perspective view, FIG. 7 is an enlarged side view showing the operation, FIG. 8 is a perspective view, FIG. 9 is a side view showing a third embodiment of the present invention, and FIG. 10 is a perspective view of the main parts thereof. 11 is a flat view 1, FIG. 12 is a side view showing a modified example, FIG. 13 is a side view showing a fourth embodiment of the present invention, and FIG.
4 is a perspective view of the main parts thereof, FIG. 15 is a perspective view showing a fifth embodiment of the present invention, FIG. 16 is a side view showing a sixth embodiment of the present invention, and FIG. 17 is a perspective view of the present invention. It is a side view which shows the seventh Example. 27... Confidential document, 28... Confidential image information, 29.
...Fluorescent material applicant Ricorn Co., Ltd.

Claims (1)

[Claims] A fluorescent substance that emits light at a wavelength different from the wavelength of the irradiated light is present in at least a part of the document carrying confidential image information, and the document is irradiated with the irradiated light and the irradiated light is received. A method for preventing copying of a confidential document, in which a detection means detects light emitted from a fluorescent substance, and the detection signal is used to immobilize or stop at least a part of the copying operation so as to make copying impossible. A method for preventing duplication of confidential documents, characterized in that a substance that has a photostimulation effect with long wavelength light is used as the substance.