JP2007169837A - Recording medium and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a recording medium containing a magnetic substance which is hardly checked visually from the outside and to provide a method for producing the same. <P>SOLUTION: For example, first base paper 102 is bonded to second base paper 104 through an adhesive layer 106 composed of an adhesive. The magnetic substance 108 is dispersed into the adhesive layer 106 and contained in a randomly arranged state in the recording medium 100. The magnetic substance 108 is randomly arranged in the recording medium 100 or lined and arranged in a fixed direction according to a production condition. In the figure, the magnetic substance 108 is contained only in the adhesive layer 106 and the magnetic substance 108 penetrateds the first base paper 102 and the second base paper 104 and exists in them in a pressing process after lamination in production. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a recording medium that can be printed using a general recording material such as ink or toner, and that can be detected by magnetic or electromagnetic means, and a manufacturing method thereof.

  In recent years, with the spread of computers, multifunction peripherals, and networks, it has become possible to easily acquire desired information from a vast amount of information, and to print and copy the acquired information.

  In view of this, various apparatuses and methods have been proposed in which security of information is enhanced in order to prevent leakage of confidential information caused by taking out a printed material on which information is illegally copied or printed.

  For example, by using a combination of a printing paper containing a magnetic material capable of recording unique identification information and an information reading device that reads the identification information and determines the validity of the information printed on the printing paper. A method for enhancing the security of information has been proposed (see Patent Documents 1 and 2).

JP 2004-284053 A JP 2004-285524 A

  However, the magnetic material does not transmit visible light, whereas the pulp material, which is a matrix material constituting the printing paper, transmits visible light. In addition, while many of the magnetic materials have a dark color with low brightness, printing paper is usually used based on white. Therefore, the magnetic material contained in the printing paper is easily visually recognized from the outside.

  In this case, since it can be determined at a glance that it is a form for ensuring the security of information, a person who tries to steal confidential information can easily allow theft by other means. As a result, information security cannot be improved, and confidential information may be leaked or falsified.

  Therefore, an object of the present invention is to solve the above problems. That is, an object of the present invention is to provide a recording medium in which a magnetic material is difficult to visually recognize from the outside, and a manufacturing method thereof.

The above problem is solved by the following means. That is,
The recording medium of the present invention is
The first base paper,
A second base paper to be bonded to the first base paper;
An adhesive layer interposed between the first base paper and the second base paper and containing a magnetic material;
It is characterized by having.

  In the recording medium of the present invention, the magnetic body is preferably a magnetic wire. The magnetic medium preferably has a large Barkhausen effect. Moreover, it is preferable that the said magnetic body is coat | covered with the layer which has insulation. The magnetic body preferably has an outer diameter of 20 to 50 μm. The adhesive is preferably a water-soluble adhesive, particularly a starch-based adhesive.

On the other hand, the manufacturing method of the recording medium of the present invention includes:
Applying an adhesive containing a magnetic material to the surface of the first base paper;
Bonding the first base paper and the second base paper through the adhesive;
It is characterized by having.

  According to the present invention, it is possible to provide a recording medium in which the magnetic body is difficult to visually recognize from the outside, and a method for manufacturing the recording medium.

  Hereinafter, the present invention will be described in detail with reference to the drawings. In addition, the same code | symbol is provided to the member which has the substantially same function through all the drawings, and the overlapping description may be abbreviate | omitted.

  FIG. 1 is a plan view showing a recording medium according to the embodiment. FIG. 2 is a cross-sectional view taken along the line AA of FIG. FIG. 3 is a schematic configuration diagram illustrating a recording medium manufacturing apparatus according to the embodiment.

  As shown in FIGS. 1 and 2, the recording medium 100 according to the embodiment has a first base paper 102 and a second base paper 104 bonded together with an adhesive layer 106 made of an adhesive. The magnetic material 108 is dispersed in the adhesive layer 106 and is included in a state of being randomly arranged in the recording medium 100.

  The magnetic body 108 may be randomly arranged in the recording medium 100 or may be arranged in a predetermined direction depending on manufacturing conditions. Further, in the drawing, the magnetic body 108 is included only in the adhesive layer 106, but the magnetic body 108 is also embedded in the first base paper 102 and the second base paper 104 in the pressing step after bonding at the time of manufacture. May also exist.

  As described above, the recording medium 100 according to the embodiment exists such that the magnetic body 108 is sandwiched between the first base paper 102 and the second base paper 104. Therefore, the magnetic body included in the recording medium is generally used. Even under difficult environments and usage conditions (for example, when placed on a desk under normal indoor lighting or sunlight, or when a recording medium is viewed through light) Yes. As a recording medium, a good image can be formed by an electrophotographic method or an inkjet method.

  In addition, since the magnetic substance 108 is dispersed in the adhesive layer 106, it is included in the recording medium with better dispersibility than in the case where it is contained in the base paper, and the detection capability is greatly improved.

  In addition, a material with low permeability can be selected as the base paper, and an adhesive with low permeability can be selected, so that the permeability can be lowered, and the magnetic material can be made more difficult to be easily visually recognized from the outside. Can do.

  In addition, in the case of a method in which a magnetic material is encased in a single process, the selection of each paper layer such as thickness and transmittance (whiteness) is limited, whereas in the present invention, the thickness and material selectivity as described above. The restriction is reduced.

  Hereinafter, each component (material) will be described in detail. Note that the reference numerals are omitted.

  First, the magnetic material will be described. The magnetic material is not particularly limited as long as it is made of a magnetic material having characteristics that cause a large Barkhausen effect. However, as magnetic properties, it is preferable that the hysteresis loop is substantially rectangular and the coercive force (Hc) is relatively small.

  The composition of the magnetic material is, for example, a magnetic element (eg, Co, Fe, Ni), an alloy containing transition metals and a glass forming element (eg, Si, B, C, P) (eg, Co-based, Fe System, Ni system, mixed system of these, etc., specifically Co—B—Si, Co—Fe—B—Si, etc.), and by selecting the composition ratio of the constituent elements and the production method Those with various magnetic properties can be used. Note that the hue of an amorphous alloy composed of the above elements is not significantly affected by the ratio of the elements.

  The shape of the magnetic material is not particularly limited as long as it is suitable for causing the large Barkhausen effect, but a predetermined length with respect to the cross-sectional area is required to cause the large Barkhausen effect. In view of this, a linear shape (wire shape) or a belt shape is preferable, and a wire shape is more preferable.

  The magnetic material should be such that the magnetic material is exposed on the surface of the recording medium, or the magnetic material is dispersed so that it is not located near the surface. Is good. On the other hand, in order for the magnetic body to have a large Barkhausen effect, the outer diameter is preferably 10 or more.

  For this reason, for example, when a magnetic material is included in a recording medium having a thickness of 80 to 120 μm, for example, a wire-like magnetic material (magnetic wire) has a circular cross section and an outer diameter of 10 to 60 μm, More preferably, it is 15-55 micrometers, More preferably, it is 15-35 micrometers. On the other hand, the length of the wire-like magnetic body (magnetic wire) depends on the outer diameter, and when the outer diameter is 10 to 60 μm, it is preferably 10 to 40 mm, more preferably 10 to 30 mm, Preferably it is 15-25 mm.

  The magnetic material can be used as it is dispersed in the adhesive, but is preferably covered with an insulating layer (hereinafter sometimes referred to as “insulating layer”). This is because, when the magnetic material enters the recording medium, the volume resistance value of the recording medium is reduced, or if it is exposed to the surface of the recording medium, an electrical short circuit occurs in the transfer process in the electrophotographic recording process. This is because it may be difficult to apply to PPC applications or the large Barkhausen effect may be hindered. Such a magnetic body is, for example, a composite material having a fiber shape in which an amorphous magnetic body having soft magnetism is used as a magnetic core, and the magnetic core is covered with an insulating layer.

  The material constituting the insulating layer is not particularly limited as long as it is a known insulating material, and for example, resin, glass, or the like can be used. In addition, when using resin as an insulating material, it is preferable to use polyimide resin etc. which have heat resistance.

  Such an insulating layer preferably has a thickness of 2.5 to 10 [mu] m, more preferably 3.0 to 8.0 [mu] m, in order to exhibit its covering effect.

  The method for forming the insulating layer is not particularly limited, and depending on the material for forming the insulating layer, vapor deposition methods such as sputtering, CVD (Chemical Vapor Deposition), vacuum deposition, dip coating, roller coating, spray coating, A known thin film forming method such as a liquid phase film forming method such as coating using a sol-gel method can be appropriately selected. However, in order to form a uniform and thinner insulating layer, a vapor phase film forming method can be used. Is preferred. The insulating layer can be formed almost simultaneously with the wire formation of the magnetic material. For example, immediately after the molten magnetic material is processed into a wire shape, the magnetic material wire is cooled and CVD is performed. The insulating layer can also be formed by a phase film formation method.

  When the recording medium is applied to a PPC application, the magnetic material is assumed to pass through a high-heated portion through a fixing heater or the like for toner fixing. Therefore, considering the fixing temperature, the Curie temperature of the magnetic material is preferably 200 ° C. or higher, and more preferably 300 ° C. or higher.

  Here, the Curie temperature is measured as follows. The temperature dependence curve of saturation magnetization is collected, and is derived by extrapolating the temperature at which saturation magnetization = 0. In order to obtain the temperature dependence curve of saturation magnetization, an apparatus disclosed in Japanese Patent Application Laid-Open No. 2003-302378 can be used. It includes a temperature control device such as a heater for changing the ambient temperature, a thermometer, an exciter that applies a magnetic field to a sample (magnetic wire in the present invention), and a magnetic flux detector. In the present invention, since the Curie temperature is in the temperature range above room temperature, a cooling device such as a refrigerator shown in the figure is unnecessary.

  The magnetic body is obtained by melting a magnetic material, passing it through a discharge port having a shape corresponding to a desired cross-sectional shape, and then cooling it. Specifically, for example, an underwater rotary spinning method can be used.

  Also, the magnetic body and the insulating layer can be manufactured almost simultaneously. For example, immediately after a molten magnetic material is processed into a wire shape having a desired cross-sectional shape, a method of applying an insulating layer by a vapor deposition method such as CVD, which also serves as cooling of the magnetic material, can be applied. it can.

  In addition, a magnetic wire covered with glass (insulating layer) can also be produced by a production method described in USP 3,256,584 (Taylor-Ulitovsky method). That is, a metal alloy is charged in the glass tube, and the tip of the glass tube is heated and melted by an induction coil to create a state where the periphery of the metal melting material is covered with melted glass, which is rapidly cooled with a cooling medium. Thereby, the magnetic body which coat | covered the amorphous magnetic wire with glass can be obtained.

  The inclusion amount of the magnetic material in the recording medium will be described below. It is preferable that 1 to 30 magnetic materials are included in the recording medium, more preferably 3 to 20, and more preferably 5 to 15. When A4 paper and A3 paper are manufactured by cutting after paper making, it is assumed that the A4 paper having a small size includes the above number. Therefore, the inclusion amount cannot be defined by the inclusion density. This is because if the paper size is smaller than the A4 paper size, the necessary inclusion density in the case of A4 increases.

If the size of the recording medium is A4 paper (297 mm * 210 mm) and the wire length is 25 mm, the required inclusion density is calculated below. Inclusion amount to the recording medium of the magnetic material is preferably from 0.0014 to 0.0393 present / cm ^2, and more preferably a 0.00393 to 0.0262 present / cm ^2, more preferably 0 .00655 to 0.0196 / cm ² . By setting the inclusion amount within the above range, detection using the large Barkhausen effect is possible, and the function (recording ability and appearance) as a recording medium can be improved. When the wire length is shorter than 25 mm, the large Barkhausen signal amount per line decreases, so the number increases.

  Next, the adhesive will be described. Although there is no restriction | limiting in particular as an adhesive agent, A water-soluble adhesive agent is mentioned suitably. Water-soluble adhesives are water-soluble and can be easily diluted with water, so they are easy to handle.Easy to clean with water without damaging the machine.Since no solvent is used, there is no risk of fire. It is suitable because it is degradable and is environmentally friendly and suitable for paper recycling.

  Examples of water-soluble adhesives include starch adhesives, glue adhesives, emulsion adhesives, and casein adhesives, with starch adhesives being preferred. Use of this starch adhesive is preferable because it is inexpensive and easy to handle.

  Here, the starch adhesive refers to an adhesive containing starch as a component. The starch may be starch that can be used in a one-tank or two-tank stain hole method, a premix method, a no carrier method, and the like, and is not particularly limited. Specifically, for example, starches such as corn starch, potato, tapioca, wheat, sweet potato, etc., and these modified starches that have been oxidized, acid-treated, etherified, esterified and grafted according to conventional methods, and combinations of these starches And the starch which gelatinized the said starch can be used.

  Next, the first base paper and the second base paper (hereinafter collectively referred to as “base paper”) will be described. The base paper contains at least pulp fibers as a main raw material, and may be a base paper described below, or may be a base paper whose surface is treated with a pigment or a binder.

  The base paper contains pulp fibers, but known pulp fibers can be used. Specifically, chemical pulp, specifically hardwood bleached kraft pulp, hardwood unbleached kraft pulp, softwood bleached kraft pulp , Softwood unbleached kraft pulp, hardwood bleached sulfite pulp, hardwood unbleached sulfite pulp, softwood bleached sulfite pulp, softwood unbleached sulfite pulp, etc. Used pulp can be used.

  In addition, ground wood pulp that mechanically pulped wood and chips, chemimechanical pulp mechanically pulped after soaking chemicals into wood and chips, and pulp with a refiner after the chips are digested until they are slightly soft Thermomechanical pulp that has been made into a material can also be used. These may be used only with virgin pulp, or waste paper pulp may be added as necessary.

  In particular, pulp used in virgin is bleached mainly using ozone / hydrogen peroxide without using chlorine gas and without using chlorine gas (Elementary Chlorine Free; ECF) or chlorine compounds. It is preferably one that has been bleached by a method (Total Chlorine Free; TCF).

  In addition, as raw materials for waste paper pulp, unprinted waste paper such as cuts, damaged paper, widened white, special white, medium white, and white loss generated in bookbinding, printing factories, cutting offices, etc .; printing and copying Used high-quality printed paper, high-quality coated paper, etc .; used paper printed with water-based ink, oil-based ink, pencil, etc .; printed high-quality paper, high-quality coated paper, medium-sized paper, medium-sized coated paper, etc. Including used newspapers; used paper such as medium quality paper, medium quality coated paper, and reprint paper;

  The waste paper pulp is preferably obtained by treating the waste paper raw material with at least one of ozone bleaching treatment and hydrogen peroxide bleaching treatment. Moreover, in order to obtain a base paper with higher whiteness, it is desirable that the blending ratio of the used paper pulp obtained by the bleaching treatment is 50% by weight or more and 100% by weight or less. Furthermore, from the viewpoint of resource reuse, it is more desirable that the ratio of waste paper pulp is 70 wt% or more and 100 wt% or less.

  Ozone treatment has the effect of decomposing fluorescent dyes and the like normally contained in fine paper, and hydrogen peroxide treatment has the effect of preventing yellowing due to alkali used during deinking treatment. In particular, it is known that the combination of the two not only facilitates deinking of waste paper, but also improves the whiteness of the pulp. Moreover, since it also has an action of decomposing and removing residual chlorine compounds in the pulp, it has a great effect in reducing the content of organic halogen compounds in used paper using chlorine-bleached pulp.

Further, it is preferable to add a filler to the base paper in order to adjust the opacity, whiteness and surface property. In particular, when it is desired to reduce the halogen content in the recording medium, it is preferable to use a filler containing no halogen.
Fillers include heavy calcium carbonate, light calcium carbonate, chalk, kaolin, calcined clay, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc sulfide, zinc carbonate, aluminum silicate, calcium silicate, magnesium silicate, synthetic Examples include white inorganic pigments such as silica, aluminum hydroxide, alumina, sericite, white carbon, saponite, calcium montmorillonite, sodium montmorillonite, and bentonite, and organic pigments such as acrylic plastic pigment, polyethylene, and urea resin. . Moreover, when mix | blending waste paper, it is necessary to estimate the ash content contained in a waste paper raw material previously, and to adjust addition amount.

  Furthermore, it is preferable to add an internal sizing agent to the base paper. As the internal sizing agent, neutral rosin sizing agents, alkenyl succinic anhydride (ASA), alkyl ketene dimer (AKD), and petroleum resin sizing agents used for neutral papermaking can be used.

  In addition, when the surface of the base paper is adjusted to be cationic, the cationic substance can be treated with, for example, a hydrophilic cationic resin on the surface, but the penetration of the cationic resin into the inside is suppressed. In order to achieve this, it is preferable that the paper sizing degree before applying the cationic resin is 10 seconds or more and less than 60 seconds.

  Further, a paper strength enhancer can be internally or externally added to the base paper as required. Paper strength enhancers include starch, modified starch, vegetable gum, carboxymethylcellulose, polyvinyl alcohol, polyacrylamide, urea-formaldehyde resin, melamine-formaldehyde resin, dialdehyde starch, polyethyleneimine, epoxidized polyamide, polyamide / epichlorohydrin resin , Methylolated polyamide, chitosan derivatives and the like, and these materials can be used alone or in combination.

  In addition to these, various auxiliaries such as dyes and pH adjusters that are blended in ordinary paper media are appropriately used.

  The base paper may be surface-treated with a surface sizing liquid or a coating layer may be provided as necessary. For surface treatment, coating liquid for surface sizing or coating layer formation is usually applied using size press, shim size, gate roll, roll coater, bar coater, air knife coater, rod blade coater, blade coater, etc. Can be performed by applying to the base paper. s

  Moreover, in order to make it difficult to visually recognize the magnetic substance from the outside more effectively, the base paper can be provided with a coat layer mainly composed of a pigment and an adhesive as necessary. This coat layer is preferably provided after the first base paper and the second base paper are bonded together.

  Examples of the pigment used in this coat layer include pigments used in ordinary general coated paper, such as heavy calcium carbonate, light calcium carbonate, titanium dioxide, aluminum hydroxide, satin white, talc, calcium sulfate, barium sulfate, Mineral pigments such as zinc oxide, magnesium oxide, magnesium carbonate, amorphous silica, colloidal silica, white carbon, kaolin, calcined kaolin, delaminated clay, aluminosilicate, sericite, bentonite, smectite, and polystyrene resin fine particles Urea formaldehyde resin fine particles, fine hollow particles, and other organic pigments can be used alone or in combination.

As an adhesive used for the coat layer, a synthetic adhesive or a natural adhesive can be used.
Synthetic adhesives include styrene / butadiene, styrene / acrylic, ethylene / vinyl acetate, butadiene / methyl methacrylate, vinyl acetate / butyl acrylate, and other copolymers, polyvinyl alcohol, maleic anhydride copolymer, Examples thereof include acrylic acid / methyl methacrylate copolymer. Among these synthetic adhesives, one or more types can be used depending on the purpose. These adhesives are preferably used in the range of about 5 to 50% by weight, more preferably about 10 to 30% by weight per 100% by weight of the pigment.

  Examples of natural adhesives include generally known adhesives such as oxidized starch, esterified starch, enzyme-modified starch, cold water soluble starch obtained by flash drying them, casein, and soy protein. These adhesives are also used in the range of about 0.1 to 50% by weight, more preferably about 2 to 30% by weight per 100% by weight of the pigment.

  Moreover, various auxiliary | assistant mix | blended with the pigment for normal coated papers, such as a dispersing agent, a thickener, a water retention agent, an antifoamer, and a water resistance agent, are used suitably as needed.

The coating composition prepared to contain the components as described above is a coating apparatus used in general coated paper production, such as a blade coater, an air knife coater, a roll coater, a reverse roll coater, a bar coater, a curtain coater, A die slot coater, a gravure coater, or the like can be applied on the base paper in one layer or multiple layers by on-machine or off-machine. The coating amount is generally applied so that the dry weight is about 5 to 15 g / m ^{2 on} one side. However, in the present invention, in order to make it difficult to visually recognize the magnetic material from the outside, It may be larger than the range.

  For the smoothing treatment after coating, a commonly used smoothing device, for example, a super calendar, a machine calendar, a soft nip calender or the like is used, and it is preferably finished so that the gloss of the blank paper is 30% or more.

  The thickness of the base paper is preferably 20 to 60 μm, more preferably 30 to 50 μm, and still more preferably 35 to 50 μm, since the thickness of the recording medium is preferably 80 to 200 μm.

The use of the recording medium having such a configuration is not particularly limited, and examples thereof include an electrophotographic recording medium and an inkjet recording medium. For example, when applied to an electrophotographic recording medium, for example, the surface electrical resistivity under the environmental conditions of 22 ° C. and 55% RH is in the range of 1.0 × 10 ^{9 to} 1.0 × 10 ¹¹ Ω, The volume resistivity at an environmental condition of 22 ° C. and 55% RH is preferably in the range of 1.0 × 10 ^{10 to} 1.0 × 10 ¹² Ω · cm. Thus, when printing is performed by an electrophotographic recording method, toner transfer failure does not occur, and a clear image quality can be obtained.

  The recording medium having the surface electrical resistivity and the volume electrical resistivity can be obtained by selecting each constituent material according to, for example, Japanese Patent Application Laid-Open No. 2003-76051.

  Hereinafter, a method for manufacturing a recording medium according to the embodiment will be described. The recording medium according to the embodiment is obtained by applying an adhesive containing a magnetic substance to the surface of the first base paper, and then bonding the first base paper and the second base paper through the adhesive. After bonding, a post-process such as a pressing process may be performed.

  An example of a manufacturing apparatus used in the recording medium manufacturing method according to the embodiment is the manufacturing apparatus shown in FIG.

  The recording medium manufacturing apparatus shown in FIG. 3 is for pasting the first base paper 10 and the second base paper 20 through an adhesive. As shown in FIG. 3, the manufacturing apparatus includes a second base paper supply roll 21 that supplies the second base paper 20 by feeding, and the second base paper 20 supplied from the second base paper 20 is first in the middle of the path. After being bonded to the base paper 10, it is taken up by a take-up roller 40 disposed on the downstream side.

  In addition, a plurality of tension rollers 21 a, 21 b, 33 a, 33 b for applying appropriate tension to the second base paper 20 are provided between the second base paper supply roll 21 and the take-up roller 40.

  Below the path of the second base paper 20, a first base paper supply roll 11 for supplying the first base paper 10 by feeding, an adhesive application unit 12 for applying the adhesive 15 to the fed first base paper 10, and Is arranged.

  The adhesive application unit 12 includes an application roller 13 that applies an adhesive 15 to the first base paper 10 by rotation. A part of the application roller 13 is in an adhesive tank 14 in which the adhesive 15 is accommodated. Soaked.

  Here, a magnetic material (not shown) is dispersed in the adhesive 15 accommodated in the adhesive tank 14. The magnetic substance is dispersed in the adhesive 15 by providing a stirring means (not shown) at the bottom of the adhesive tank 14 so that the flow of the adhesive 15 is directed from the bottom of the adhesive tank 14 to the top by the stirring means. To do. Examples of the stirring means include a rotary blade, a jet flow, and bubbling.

  In addition, the accumulation of the magnetic substance in the adhesive 15 on the bottom of the adhesive tank 14 due to the gravity drop causes a decrease in dispersibility, but the magnetic substance once lifted up by the stirring means is caused by the viscosity of the adhesive. The falling speed of the wire is reduced and the dispersibility is improved as compared with the case of water alone.

  On the other hand, a doctor blade 16 as a scraping part for scraping off the adhered adhesive 15 is in contact with the surface of the application roller 13. The doctor blade 16 is disposed in front of the contact 13 a between the first base paper 10 and the application roller 13.

  A laminating roller 31 is provided above the application roller 13, and the first base paper 10 coated with the adhesive 15 by the application roller 13 and the second base paper 20 are in contact with each other. In addition, a pressing roller 32 is provided on the downstream side of the laminating roller 31 at a position having no contact with the laminating roller 31, and the first base paper 10 and the second base paper 20 sent from the laminating roller 31 are provided. Is arranged so as to press downward.

  In addition, if the space | interval of the roller 31 for bonding and the press roller 32 is about 10-50 cm, the 1st base paper 10 and the 2nd base paper 20 can be bonded together reliably.

  Next, the first base paper 10 supplied from the first base paper supply roll 11 and the second base paper 20 supplied from the second base paper supply roll 21 are bonded together, and the recording medium 100 in which the magnetic material is contained in the adhesive layer. A procedure for forming the film will be described.

  The first base paper 10 is sent out from the first base paper supply roll 11 and sent to the coating roller 13 via the tension rollers 41a and 41b. The tension rollers 41a and 41b support the first base paper 10 so that the tension (tension) of the supplied first base paper 10 is kept constant and the first base paper 10 does not rely on or wrinkle.

  On the surface of the application roller 13, the adhesive 15 (including magnetic material) adhered in the adhesive tank 14 scrapes off the excess adhesive 15 (including magnetic material) by the doctor blade 16, and contacts 13 a on the application roller 13. Is uniformly applied to one surface of the first base paper 10 in contact with the first base paper 10.

  In this way, after the first base paper 10 is uniformly coated with the adhesive 15 (including magnetic material), the first base paper 10 is applied to the laminating roller 31 so that the surface coated with the adhesive 15 (including magnetic material) is on the outside. It is wound up.

  On the other hand, the second base paper 20 sent out from the second base paper supply roll 21 is sent to the laminating roller 31 in a state where a predetermined tension is applied by the tension rollers 21a and 21b. The second base paper 20 wound around the laminating roller 31 is in contact with the surface of the first base paper 10 to which the adhesive 15 is applied at the upper portion 31a of the laminating roller 31 and adheres to the second base paper 20.

  Subsequently, the first base paper 10 and the second base paper 20 that have passed through the laminating roller 31 are pressed by the pressing roller 32.

  Finally, the first base paper 10 and the second base paper 20 that are determined to be bonded by the bonding roller 31 and the pressing roller 32 are taken up by the take-up roller 40 via the tension rollers 33a and 33b as the recording medium 100.

  The wound recording medium is cut into a predetermined size and used. The recording medium manufacturing apparatus (manufacturing method) is not limited to the above, and can be obtained by a known apparatus (method).

  The recording medium according to the present embodiment is recorded by a known recording method, but the confidential information expressed by the printed image quality is to detect a magnetic signal from a magnetic material included in the printed recording medium. Therefore, it is possible to suppress copying, and it is possible to suppress taking out the recording medium from a predetermined space. Note that signal detection using the large Barkhausen effect is described in Japanese Patent Application Laid-Open No. 2003-308576 and conforms to this description.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to only these examples.
Example 1
-Magnetic material-
As the magnetic material, an Fe—Co amorphous magnetic material wire (Hc = 19.1 A / m) having a length of 25 mm and a diameter of 27 μm was prepared. This magnetic wire is gray black, and the color coordinates L *, a *, b * of the L * a * b * color system defined by JIS Z 8729 are 16.9, 0.0, 12. 6.
Next, an insulating layer having a thickness of about 5 μm and a camouflage layer having a thickness of about 2 μm were sequentially laminated on the magnetic body wire by the following procedure to obtain a coated magnetic body wire. The magnetic wire after the coating treatment is white.

-Formation of insulating layer-
The insulating layer was formed by processing the melted magnetic material into a wire shape and passing the magnetic wire through the sealed chamber and simultaneously depositing a silica film in the chamber.

−Preparation of base paper−
Contains 80 parts by weight of hardwood bleached kraft pulp (LBKP), 10 parts by weight of softwood bleached kraft pulp (NBKP) and 10 parts by weight of organic synthetic fiber (generic name: para-aramid fiber, trade name: Technora, manufactured by Teijin Ltd.) To a pulp slurry having a freeness of 430 ml obtained by beating the pulp slurry with Niagara Beata (manufactured by Kumagai Rikkoku Kogyo Co., Ltd.), light calcium carbonate (Tamapearl TP-121, Okutama Industry ( 8 parts by weight, 0.5 parts by weight of aluminum sulfate, 0.5 parts by weight of cationized starch (trade name: MS4600, manufactured by Nippon Food Chemical Co., Ltd.), alkenyl succinic anhydride (Fibrane 81, Oji National) Co., Ltd.) 0.09 parts by weight and crosslinking agent (generic name: carbodiimide-based crosslinking agent, carbodilite V-04) 0 Was added 8 parts by weight, the mixture is diluted with white water to prepare a solid concentration of 0.3% by weight of the pulp slurry.

After stirring this pulp slurry for 2 hours, paper was made using an oriented sheet former (manufactured by Kumagai Riki Kogyo Co., Ltd.) under a jet pressure of 1.5 kg / cm ² and a drum rotation speed of 950 m / min. Two wet papers were stacked.

Subsequently, a laminate of the two wet papers was pressed for 3 minutes at a press pressure of 10 kg / cm ² using a square sheet machine press 2570 (manufactured by Kumagai Riki Kogyo Co., Ltd.).

Next, oxidized starch (Ace B, manufactured by Oji Corn Starch Co., Ltd.) was applied to the wet paper with a size press device so that the coating amount was 2.5 g / m ² in terms of dry weight, and after drying, A smoothing process was performed with a machine calendar so that the Oken smoothness was 30 seconds, and a base paper having a basis weight of about 52 g / m ² was produced and wound into a roll.

-Production of recording media-
First, as the adhesive, a carrier starch dispersion added to a porous corn starch in which a bonding improver and a water resistance-imparting agent were supported in the pores and stirred was used. The magnetic substance was dispersed in a water-diluted solution of the starch-based adhesive in an amount such that an average of 3 to 20 magnetic wires were contained on an A4 size paper. The blending amount depends on the amount of paper making, the thickness of the adhesive layer, and the like.

  Then, two adhesives containing a magnetic material and two roll-shaped base papers were attached to the manufacturing apparatus shown in FIG. 3, and after applying the adhesive to one of the base papers, the other base paper was pasted through the adhesive. Then, it cut | judged to the predetermined magnitude | size and obtained the recording medium.

In this way, a recording medium was obtained. When the visibility of the magnetic wire was evaluated by visual observation of the obtained recording medium, it was possible to realize the visibility difficulty to the extent that the embedded position of the magnetic wire could hardly be identified. Since the magnetic wire is located between the two base papers, the stability of the visibility difficulty is good.
(Comparative example)
Papermaking was performed in the same manner as in Example 1 except that the magnetic material was added to the pulp slurry in such an amount that 3 to 20 magnetic wires were included on the A4 size paper on average. This was subjected to press, size press, and smoothing treatment, wound into a roll, and then cut into a predetermined size to obtain a recording medium.

  In this way, a recording medium was obtained. When the obtained recording medium was evaluated by visual recognition of the magnetic wire, the magnetic wires were randomly arranged in the two paper layers and sometimes located near the surface. It was possible to almost distinguish the burial position, and lacked visibility.

  It can be seen that the recording medium produced in this example has high detection ability and the magnetic material is difficult to see. As described above, the recording medium of the present invention can record a confidential document in an office, for example, and the confidential information can be suppressed by detecting a magnetic signal from a magnetic material included in the printed recording medium. It is also possible to prevent the recording paper from being taken out of a predetermined space. Thus, it can be seen that leakage of confidential information of the document can be suppressed for each sheet.

It is a top view which shows the recording medium which concerns on embodiment. It is AA sectional drawing of FIG. 1 is a schematic configuration diagram illustrating a recording medium manufacturing apparatus according to an embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 1st base paper 11 1st base paper supply roll 12 Adhesive application part 13a Contact 13 Application roller 14 Adhesive tank 15 Adhesive 16 Doctor blade 20 2nd base paper 21 2nd base paper supply roll 21a, 21b Tension roller 31 Rolling roller 31a Upper part of laminating roller 32 Pressing rollers 33a, 33b Tension roller 40 Take-up rollers 41a, 41b Tension roller 100 Recording medium 102 First base paper 104 Second base paper 106 Adhesive layer 108 Magnetic body

Claims (8)

The first base paper,
A second base paper to be bonded to the first base paper;
An adhesive layer interposed between the first base paper and the second base paper and containing a magnetic material;
A recording medium comprising:   The recording medium according to claim 1, wherein the magnetic body is a magnetic wire.   The recording medium according to claim 1, wherein the magnetic medium has a large Barkhausen effect.   The recording medium according to claim 1, wherein the magnetic body is covered with an insulating layer.   The recording medium according to claim 1, wherein the magnetic body has an outer diameter of 20 to 50 μm.   The recording medium according to claim 1, wherein the adhesive is a water-soluble adhesive.   The recording medium according to claim 1, wherein the adhesive is a starch-based adhesive. Applying an adhesive containing a magnetic material to the surface of the first base paper;
A step of bonding the first base paper and the second base paper through the adhesive;
A method for producing a recording medium, comprising:

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