Recording medium and sheet

The present invention relates to a recording medium and a sheet containing a magnetic material capable of printing with a general recording material such as toner or ink and recording / reproducing information by magnetic means.

In recent years, laws such as personal information protection, privacy mark system, and information security have been put in place to prevent information leakage. However, due to the convenience of portability and storage of recording paper, the current situation is that information leakage such as personal information and confidential information printed on recording paper is not completely suppressed. Therefore, there is an urgent need to prevent the leakage and forgery of confidential information recorded on the recording paper without impairing the convenience of the recording paper.

Various proposals have been made to address such issues. For example, in the process of recording a unique identification number on a recording paper in advance and printing an image on the recording paper in an image forming apparatus such as a printer, the unique identification number of each recording paper is read to maintain the confidentiality of the document. A technique for determining whether or not an image is an original has been proposed (see, for example, Patent Document 1).

According to the technique of Patent Document 1, copyability information is recorded in a database in advance in association with an identification number recorded on a recording paper, and when the copier reads a unique identification number for each recording paper, the read identification is performed. Whether or not copying to recording paper is possible is determined based on the copyability information corresponding to the information. Further, in the technique of Patent Document 1, a barcode or a wireless data carrier is used as a means for recording an identification number unique to the recording paper, and in particular, wireless data produced by a two-dimensional barcode or a semiconductor. It is said that the case of using a carrier is suitable because the form of assigning the identification number can be reduced.

However, in the technique of Patent Document 1, in order to prevent the area where images and characters can be recorded on the recording paper from being narrowed by the addition of identification information, the identification number is applied to a small part of the area on the recording paper. Therefore, there is a problem that it is easy to replace the identification number.

As a technique in which it is difficult to falsify the identification number of each recording paper, for example, the techniques shown in Patent Document 2, Patent Document 3, and Patent Document 4 have been published. In the technique of Patent Document 2, a safety line made of an amorphous ferromagnetic material having a specific BH magnetization characteristic is embedded in the recording paper as identification information for each recording paper. In this way, since the safety line is embedded as the identification number in the recording paper and the signal by the safety line is read as the identification information, it is possible to prevent the identification number from being easily tampered with.

In the techniques of Patent Document 3 and Patent Document 4, identification information is added to the paper by drawing a magnetic material having a large bulkhausen effect and characteristics such as magnetostriction vibration into the paper. In this way, since the magnetic material is extracted as the identification information in the paper, it is possible to prevent the identification number from being easily falsified.

<patcit num="1"><text>Japanese Unexamined Patent Publication No. 2001-265183</text></patcit><patcit num="2"><text>Japanese Unexamined Patent Publication No. 7-32778</text></patcit><patcit num="3"><text>Japanese Patent Application Laid-Open No. 2005-213654</text></patcit><patcit num="4"><text>Japanese Unexamined Patent Publication No. 2004-285524</text></patcit>

<p> In the techniques of Patent Documents 2 to 4, it is possible to prevent easy falsification of the identification number by embedding a magnetic material such as a safety line in the recording paper. However, in recording paper containing a magnetic material such as a safety line, the magnetic material inhibits hydrogen bonds formed between fibers such as pulp constituting the recording paper when the recording paper is produced. For this reason, when a recording paper containing a magnetic material such as a safety line is used in a commonly used image forming apparatus, external stress applied during transportation in the image forming apparatus and an electrophotographic image The forming apparatus has a problem that the magnetic material is likely to be missing from the recording medium due to an electric field or the like applied at the time of transfer. In particular, there was a problem that the paper was largely missing from the cut surface. As described above, if the magnetic material embedded in the recording paper is missing from the recording paper at the time of image formation, the inside of the image forming apparatus may be contaminated and the missing magnetic material may cause deterioration of image quality.</p><p> The present invention has been made in view of the above problems, and provides a recording medium and a sheet capable of suppressing the loss of the magnetic material at the time of image formation even though the magnetic material is contained. With the goal.</p>

<p> The above object is achieved by the following invention. That is, the present invention<u style="single">A first sheet and a second sheet containing pulp fibers oriented in the plane direction of the sheet were prepared, respectively.</u><u style="single">On the first sheet, a first region and a second region having a width of 2 mm or more form a band in a direction parallel to the orientation direction of the pulp fibers, and the orientation direction of the pulp fibers. The magnetic material is dispersed and arranged only in the first region by alternately setting in the direction orthogonal to the above.</u><u style="single">The first sheet in which the magnetic material is dispersed and arranged in the first region and the second sheet are laminated so that the orientation directions of the pulp fibers of both are in the same direction, and the laminated sheet is pressed. To make,</u><u style="single">The laminated sheet is placed on the magnetic side of the laminated sheet in the second region located between two adjacent first regions and parallel to the orientation direction of the pulp fibers of the recording medium after cutting. Cut so that the minimum value of the shortest distance to the material is 1 mm or more and 70 mm or less.</u><u style="single">This is a method for manufacturing a recording medium.</u><u style="single">The present invention is preferably a method for producing a recording medium, wherein the first sheet and the second sheet are wet paper and contain a filler, and the blending amount of the filler is 5% by mass or less. is there.</u><u style="single">According to the method for producing a recording medium of the present invention, the recording medium according to the following &lt;1&gt; to &lt;6&gt; can be provided by appropriately selecting the material and dimensions to be used. Further, as a laminated sheet before cutting in the method for producing a recording medium of the present invention, the sheet according to &lt;7&gt; below can be obtained.</u> &lt;1&gt; It contains a magnetic material and pulp fibers oriented with respect to the plane direction of the recording medium. The minimum value of the shortest distance between the end of the side parallel to the orientation direction of the pulp fiber and the magnetic material is 1 mm or more.<u style="single">70 mm or less</u>It is a recording medium characterized by being.</p><p> &lt;2&gt; The recording medium according to &lt;1&gt;, wherein the magnetic material is not exposed on the surface of the recording medium.</p><p> &lt;3&gt; The recording medium according to &lt;1&gt;, wherein the minimum value of the shortest distance between the surface of the recording medium and the magnetic material is 5 μm or more.</p><p> &lt;4&gt; The recording medium according to &lt;1&gt;, wherein the magnetic material has a large Barkhausen effect.</p><p> &lt;5&gt; The recording medium according to &lt;4&gt;, wherein the magnetic material is a linear body having a length in the range of 10 mm to 350 mm and a diameter in the range of 20 to 60 μm.</p><p> &lt;6&gt; The recording medium according to &lt;1&gt;, which has two or more layers.</p><p> &lt;7&gt; Contains magnetic material and pulp fibers oriented in the plane direction of the sheet. A band is formed in a direction parallel to the orientation direction of the pulp fibers, and is formed alternately in a direction orthogonal to the orientation direction of the pulp fibers, and does not include the first region containing the magnetic material and the magnetic material. Has a second area, A sheet characterized in that the width of the second region formed between two adjacent first regions is 2 mm or more.</p>

<p> As described above, according to the present invention, it is possible to provide a recording medium and a sheet that can suppress the loss of the magnetic material at the time of image formation even though the magnetic material is contained.</p>

The recording medium of the present invention includes a magnetic material and pulp fibers oriented in the plane direction of the recording medium, and the shortest distance between the end of a side parallel to the orientation direction of the pulp fibers and the magnetic material. It is characterized in that the minimum value is 1 mm or more. Therefore, even when an image is formed by an electrophotographic method, an inkjet method, or the like using the recording medium of the present invention, it is possible to suppress the loss of the magnetic material from the recording medium.

In a recording medium containing a magnetic material, hydrogen formed between materials such as pulp fibers located near the magnetic material when paper is produced using the magnetic material together with a material constituting the paper base material such as pulp fibers. There is a problem that the bond such as the bond is hindered by the magnetic material. Therefore, the magnetic material is difficult to be fixed in the recording medium by the surrounding material such as pulp fiber. On the other hand, in known image recording methods such as an electrophotographic method and an inkjet method, it is common to transport a recording medium at the time of image recording. For example, in an electrophotographic image forming apparatus, the recording medium is transferred from the paper feed tray to the surface of the recording medium after passing through a transfer unit that transfers the toner image on the surface of the photoconductor (or intermediate transfer body) to the surface of the recording medium. The toner image is conveyed to the outside of the machine through a fixing portion for fixing the toner image. Further, in the inkjet type image forming apparatus, the recording medium is conveyed to the outside of the machine after passing through a recording unit in which a recording head for ejecting ink from a paper feed tray is arranged. As described above, although there are differences in the path, distance, speed, and the like during transportation depending on the image recording method, a sliding load and contact stress generated during the transportation are applied to the recording medium during image formation.

From these facts, the present inventors considered that there is a possibility that the magnetic material contained in the recording medium may be chipped due to stress applied from the outside during transportation. Therefore, the present inventors put a recording medium containing a magnetic material in an electrophotographic image forming apparatus, which is a recording method in which the sliding load applied to the recording medium during transportation and the intensity and frequency of contact stress are extremely high. We diligently examined the state of the magnetic material falling off during transportation. As a result, the magnetic material contained in the recording medium is parallel to the orientation direction of the pulp fibers without missing the magnetic material from the end of the side orthogonal to the orientation direction of the pulp fibers contained in the recording medium. It was found that it was easy to fall off from the end of the side in the correct direction. Therefore, the present inventors arrange the magnetic material contained in the vicinity of the end portion of the recording medium inward from the end portion of the side in the direction parallel to the orientation direction of the pulp fiber in the direction orthogonal to this side. Therefore, it is considered that the loss of the magnetic material during the transportation of the recording medium can be prevented, and the above-mentioned present invention has been found.

The minimum value of the shortest distance between the end of the side parallel to the orientation direction of the pulp fiber (hereinafter, may be abbreviated as "end") and the magnetic material must be 1 mm or more. , This needs to be filled at both ends. Further, the minimum value of the shortest distance between the end portion and the magnetic material is preferably 2 mm or more, and more preferably 3 mm or more. If the minimum value of the shortest distance between the end and the magnetic material is less than 1 mm, the magnetic material will be chipped when the recording medium is conveyed. However, if the shortest distance between the end and the magnetic material is too large, the region in which the magnetic material is dispersed and contained in the recording medium may become too narrow. Therefore, in practice, the minimum value of the shortest distance between the end portion and the magnetic material is preferably 70 mm or less.

As described above, since the recording medium of the present invention suppresses the loss of the magnetic material during transportation, it is possible to prevent the inside of the image forming apparatus from being contaminated with the magnetic material. In addition, various secondary obstacles due to contamination by the magnetic material in the apparatus; for example, various parts in the image forming apparatus due to the magnetic material dropped from the recording medium (for example, a transport apparatus in the case of an electrophotographic apparatus). It is possible to suppress the occurrence of wear and tear, poor transport, deterioration of image quality, etc. of the transfer device, cleaning device, fixing device, etc.). Further, since the recording medium of the present invention is unlikely to be chipped of the magnetic material even if stress or the like is applied from the outside during transportation, it can be used even in a device having a large stress such as stress applied to the recording medium during transportation. .. From this point of view, the recording medium of the present invention is an image forming apparatus that conveys the recording medium at high speed regardless of the image forming method; specifically, high-speed conveying having a conveying speed of about 200 mm / s to 2000 mm / s. It can also be applied to an image forming apparatus provided with a recording medium transporting means capable of performing the above.

The recording medium of the present invention has a square shape and has a pair of sides parallel to each other (that is, the MD direction of the recording medium (the traveling direction of the paper machine) or the CD direction (in the traveling direction of the paper machine). The pulp fibers are oriented with respect to the direction in which they intersect vertically)). Here, "the pulp fibers are oriented" means all the states other than the state in which the pulp fibers are completely isotropically oriented with respect to the plane direction of the recording medium. The orientation direction of the pulp fibers is the ultrasonic propagation velocity in the MD direction of the recording medium (the traveling direction of the paper machine) and the ultrasonic propagation velocity in the CD direction of the recording medium (the direction perpendicular to the traveling direction of the paper machine). In comparison with, it means the direction having the larger ultrasonic propagation velocity, and when both ultrasonic propagation velocities are equal, it means the state in which the pulp fibers are completely isotropically oriented. Here, the ultrasonic propagation velocity can be measured using a SonicSheetTester (manufactured by Nomura Shoji Co., Ltd.).

The ratio of the ultrasonic propagation velocity in the orientation direction of the pulp fiber to the ultrasonic propagation velocity in the direction orthogonal to the orientation direction of the pulp fiber (ultrasonic propagation velocity in the orientation direction of the pulp fiber / the direction orthogonal to the orientation direction of the pulp fiber) The higher the ultrasonic propagation velocity), the more likely it is that the magnetic material contained in the vicinity of the end of the side in the direction parallel to the orientation direction of the pulp fiber will fall off due to stress applied during transportation of the recording medium. However, in the present invention, since the magnetic material is included at a position where the shortest distance from the end is 1 mm or more, the ultrasonic propagation velocity in the orientation direction of the pulp fibers / the ultrasonic waves in the direction orthogonal to the orientation direction of the pulp fibers. It is possible to suppress the dropout of the magnetic material regardless of the magnitude of the propagation velocity value. Further, for the above-mentioned reason, in the present invention, the orientation state of the pulp fibers in the recording medium represented by the ratio of the ultrasonic propagation velocity is orthogonal to the ultrasonic propagation velocity in the orientation direction of the pulp fibers / the orientation direction of the pulp fibers. The ultrasonic propagation velocity in the direction of pulp is preferably 1.1 or more, and more preferably 1.2 or more. Further, the upper limit of the ratio of the ultrasonic wave propagation velocity is not particularly limited, but is 2.7 or less in practical use. Since the orientation direction of the pulp fibers usually coincides with the MD direction of the recording medium, the value of the ultrasonic propagation velocity in the orientation direction of the pulp fibers / the ultrasonic propagation velocity in the direction orthogonal to the orientation direction of the pulp fibers is , So-called fiber orientation ratio (MD direction ultrasonic propagation velocity / CD direction ultrasonic propagation velocity).

Further, the position of the magnetic material in the plane direction of the recording medium is confirmed by the ultrasonic propagation velocity method described above, after confirming the orientation direction of the pulp fibers contained in the recording medium, and then parallel to the orientation direction of the pulp fibers. This was done by observing the magnetic material existing near the end of the side. Specifically, the image captured by the scanner on the recording medium is binarized with image processing software (for example, DIPP-98, manufactured by Detect Co., Ltd.) between the magnetic material in the recording medium and the plain part that does not contain the magnetic material. {For the binarization method, "Automatic threshold selection method based on discrimination and minimum squared criteria" (Journal of the Society of Electronics and Communication Engineers, Vol.J63-D, No.4, pp.349-356), "Basics and Applications of Digital Image Processing" (written by Yukiichi Sakai)}, from the end of the side parallel to the orientation direction of the pulp fiber (the end of the two sides) , It was confirmed at what mm position the magnetic material exists in the direction orthogonal to this side. Since a linear magnetic material is usually used in the present invention, the end portion of one magnetic material starts from the portion closest to the end of the side parallel to the orientation direction of the pulp fibers. And the shortest distance between the magnetic material and the magnetic material were obtained. This measurement was performed for all magnetic materials existing near the edges, and the smallest value (minimum value) was determined.

FIG. 1 is a schematic schematic diagram for explaining a method of measuring the shortest distance between a magnetic material existing near an end portion of a side parallel to the orientation direction of pulp fibers and the end portion. 100 represents the recording medium, 110 represents the end, 120A, 120B, and 120C represent the magnetic material, and the arrow indicated by the sign A indicates the orientation direction of the pulp fiber (not shown in the figure). When the magnetic materials to be measured are only the three magnetic materials shown in the figure, the shortest distance between the end and the respective magnetic materials 120A, 120B, 120C as shown in the figure X1, X2. , X3 was measured, and the smallest value (X1) among these values was determined as the minimum value.

The recording medium of the present invention may be produced without undergoing a cutting step, but usually, it is preferably a so-called cut sheet produced through a cutting step of cutting a large-sized sheet. In this case, the end of the recording medium of the present invention means a cutting surface. The cutting process includes all the cutting processes prior to providing the recording medium of the present invention to the user used for image formation. The cutting process is not particularly limited, but for example, a roll wound around a winder is made into a large-sized sheet through a cutter and a slitter, and then cut into a cut sheet of a desired size by guillotine cutting. Or, for example, a method in which a roll wound around a winder is made into a roll having a desired width via a cutter and a slitter, and further, the roll is made into a cut sheet by a cutter and a slitter with a small cutting machine, or a roll form having a desired width is formed. Can be mentioned.

On the other hand, since external stress such as friction due to contact with a transport member or the like is applied to the surface of the recording medium during transport, the magnetic material may be missing from the surface when the recording medium is transported. Therefore, it is preferable that the magnetic material is not exposed on the surface of the recording medium of the present invention. If the magnetic material is exposed on the surface of the recording medium, the magnetic material may be missing from the surface when the recording medium is conveyed. Further, when a recording medium in which the magnetic material is exposed on the surface passes through the transfer portion during image formation by the electrophotographic method, a leak may occur. It is particularly preferable that the magnetic material is not exposed on both sides of the recording medium. Here, the presence or absence of exposure of the magnetic material on the surface of the recording medium can be easily confirmed visually.

The minimum value of the shortest distance between the surface of the recording medium and the magnetic material is 5 μm or more in order to more reliably suppress the loss of the magnetic material from the surface of the recording medium and the leakage during image formation by the electrophotographic method. It is preferably 8 μm or more, and more preferably 8 μm or more. The larger the minimum value of the shortest distance between the surface of the recording medium and the magnetic material, the more preferable, and it is most preferable that the minimum value substantially matches the value when the magnetic material is located substantially at the center in the thickness direction of the recording medium.

Next, a method for measuring the shortest distance between the surface of the recording medium and the magnetic material existing in the recording medium (not exposed on the surface) will be described. First, in order to measure the distance between the front and back surfaces of the recording medium and the magnetic material, a cross section of the recording medium in which the magnetic material is present is prepared. The preparation of the cross-section observation sample is not particularly limited, and any cutting method that does not involve dimensional change can be used. For example, a resin impregnation method, a cutting method, a freeze-cutting method, or the like can be used.

The method for measuring the distance between the surface of the recording medium and the magnetic material is not particularly limited as long as the cross-sectional shape of the recording medium can be observed and the distance from the front and back surfaces of the recording medium can be measured. An optical microscope or a scanning electron microscope is used. (SEM), transmission electron microscope (TEM), etc. can be used. Desirably, it is preferable to use SEM and measure the distance at a magnification of 100 to 1000 times. In addition, when measuring the distance between the front and back of the recording medium and the magnetic material from the cross-sectional image obtained by SEM observation, etc., use image processing software (for example, DIPP-98, manufactured by Detect Co., Ltd.) to use the pulp layer and non-pulp layer (magnetic material). ) And binarization {For the binarization method, "Automatic threshold selection method based on discrimination and minimum squared criteria" (Journal of the Society of Electronics and Communication Engineers, Vol.J63-D, No.4, pp.349- 356), "Basics and Applications of Digital Image Processing" (written by Koichi Sakai)}, and measure the shortest distance from the surface of the recording medium to the magnetic material.

The shape of the magnetic material used in the present invention is not particularly limited, but a linear magnetic material having a length of several millimeters or more (hereinafter, may be referred to as a magnetic material wire) is preferably used. Therefore, as the measurement points, both ends and the vicinity of the center of the magnetic wire were cut to prepare a cross-section observation sample for measurement. For the measurement of the shortest distance between the magnetic wire and the surface of the recording medium for each magnetic wire, the shortest distance from both sides of the recording medium to the magnetic wire was obtained. In the measurement, 5 magnetic materials contained in this recording medium were arbitrarily selected and measured for each recording medium, and this was carried out for 50 recording media (50 sheets are measured at a total of 250 points). .. However, when the number of magnetic materials contained in one recording medium is less than 5, an arbitrary number of recording media was measured so that the total number of measurements was 250 points. The minimum value was obtained from the measured values at 250 points obtained in this way.

FIG. 2 is a schematic schematic diagram for explaining a method of measuring the shortest distance between the surface of the recording medium and the magnetic material, where 102 represents a cross section of the recording medium, 112 represents the surface of the recording medium, and 120 represents the magnetic material. As shown in the figure, the shortest distance between the recording medium surface and the magnetic material is the linear distance at which the distance between the portion of the magnetic material 120 closest to the recording medium surface 112 and the recording medium surface 112 is the shortest (in the figure, It was measured as the distance indicated by the double arrow Y).

Next, the configuration of the recording medium of the present invention will be described in more detail. The recording medium of the present invention has a paper base material containing at least pulp fibers and a magnetic material and containing pulp fibers as a main component. If necessary, a surface layer can be provided on at least one side of the paper base material. When the recording medium is composed of a plurality of layers, the magnetic material may be contained in any layer, but it is usually preferably contained in the paper base material.

The magnetic material used in the present invention is particularly preferably one having a large Barkhausen effect. Here, the large bulkhausen effect will be briefly described. FIG. 3 is a diagram for explaining the large Barkhausen effect. The large bulkhausen effect is derived from the BH characteristic shown in Fig. 3 (a), that is, a material with a nearly rectangular hysteresis loop and a relatively small coercive force (Hc), for example, Co-Fe-Ni-B-Si. This is a phenomenon in which a steep magnetization reversal occurs when an amorphous magnetic material is placed in an alternating magnetic field. For this reason, when an alternating current is passed through the exciting coil to generate an alternating magnetic field and a magnetic material is placed in the alternating magnetic field, a pulsed current flows through the detection coil placed near the magnetic material during magnetization reversal. Become.

For example, when an alternating magnetic field as shown in the upper part of FIG. 3 (b) is generated by the exciting coil, when the recording medium is placed in the generated alternating magnetic field, the detection coil is charged with the alternating magnetic field of FIG. 3 (b). A pulse current as shown in the lower row will flow.

As the magnetic material used in the present invention, a permanent magnet, for example, a rare earth-based neojuum (Nd) -iron (Fe) -boron (B) as a main component, and samarium (Sm) -cobalt (Co) are generally used. Main component, Alnico-based aluminum (Al) -Nickel (Ni) -Cobalt (Co) -based, Ferrite-based Valium (Ba) or Strontium (Sr) and iron oxide (Fe)₂O₃) As the main component, soft magnetic materials, oxide soft magnetic materials, etc., but the basic composition of the magnetic materials that cause the large bulkhausen effect is Fe-Co-Si or Co-Fe-. It is preferable to use a Ni-based amorphous magnetic material.

The shape of the magnetic material is not particularly limited as long as it is suitable for causing the large bulk Hausen effect, but in order to cause the large bulk Hausen effect, a predetermined length is required with respect to the cross-sectional area. Therefore, it is preferably linear (wire-shaped) or strip-shaped, and more preferably wire-shaped.

When the magnetic material is in the form of a wire, as described above, the minimum diameter required to cause the large Barkhausen effect is preferably 20 μm or more. The maximum diameter is not particularly limited, but in order to prevent the magnetic material from being exposed on the surface of the recording medium, the diameter depends on the thickness of the recording medium, for example, in the case of a recording medium having a thickness of about 100 μm. 60 μm or less is preferable, and 50 μm or less is more preferable.

The length is preferably 10 mm or more as the minimum length required to cause the large Barkhausen effect. The maximum length of the magnetic material may be a length that is not exposed from the recording medium when contained therein, and is not particularly limited, but is preferably 350 mm or less. Further, from the viewpoint of preventing the magnetic material from falling off from the end of the recording medium, a length of 10 mm or more is preferable.

The material constituting the paper base material is particularly long as it is a material that can be processed into a sheet having a thickness suitable for an image forming apparatus that records an image on a recording medium by an electrophotographic method, an inkjet method, or the like, such as pulp fiber. Not limited.

The pulp fiber that is the main material constituting the paper base material is not particularly limited, and is, for example, broadleaf and / or coniferous kraft pulp fiber, sulfite pulp fiber, semi-chemical pulp fiber, and chemiground pulp fiber. , Crushed wood pulp fiber, refiner ground pulp fiber, thermomechanical pulp fiber and the like are preferably used. In addition, fibers obtained by chemically modifying cellulose or hemicellulose in these fibers can also be used as needed. Furthermore, cotton pulp fiber, hemp pulp fiber, kenaf pulp fiber, bagas pulp fiber, biscous rayon fiber, regenerated cellulose fiber, copper ammonia rayon fiber, cellulose acetate fiber, polyvinyl chloride fiber, polyacrylonitrile fiber, polyvinyl alcohol fiber, Each fiber such as polyvinylidene chloride fiber, polyolefin fiber, polyurethane fiber, fluorocarbon fiber, glass fiber, carbon fiber, alumina fiber, metal fiber, silicon carbide fiber and the like can be used alone or in combination of two or more.

Further, if necessary, fibers obtained by impregnating or heat-sealing the pulp fibers with a synthetic resin such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, or polyester can also be used.

Further, high-quality and medium-quality recycled paper pulp can be further added to the pulp fiber. The blending amount of used paper pulp is determined according to the intended use and purpose. Further, from the viewpoint of resource conservation, it is preferable to use pulp obtained from so-called forest certified certified forests, planted trees or thinned wood chips.

A filler can be added to the recording medium of the present invention to adjust opacity, whiteness, and surface properties. However, from the viewpoint of maintaining the interfiber bonding force between the pulp fibers contained in the recording medium and preventing the magnetic material from being chipped, the blending amount of the filler with respect to the solid content (absolute dry weight) of the recording medium is 20% by mass. It is preferably less than or equal to, more preferably 10% by mass or less. More preferably, it is 5% by mass or less.

When the blending amount of the filler with respect to the solid content of the paper base material is more than 20% by mass, the bonds formed between the materials constituting the paper base material such as the pulp fibers constituting the paper base material may be broken or the paper base material may be broken. The distance between the pulp fibers constituting the paper base material tends to increase, and the bonding strength between the main materials constituting the paper base material decreases. Therefore, the magnetic material may be easily removed from the recording medium.

The blending amount of this filler is defined by the residual ash (JIS P 8128) after the recording medium of the present invention is incinerated according to the method specified by JIS P 8128 (575 ° C, 4 hours). It can be obtained by calculating the blending amount of the magnetic material and the filler contained in the paper base material of the recording medium by elemental analysis of the ash content by a method such as IPC luminescence analysis.

The fillers that can be used in the recording medium of the present invention include heavy calcium carbonate, light calcium carbonate, kaolin, calcined clay, pyroferrite, sericite, talc and other silicic acids, titanium dioxide and other inorganic fillers, and urea resins. , Organic pigments such as styrene, and thermoplastic resin particles such as polyester-based and styrene-acrylic-based.

Further, various chemicals such as a sizing agent can be added internally or externally to the paper base material constituting the recording medium of the present invention. Examples of the types of sizing agents that can be added to the paper substrate include sizing agents such as rosin-based sizing agents, synthetic sizing agents, petroleum resin-based sizing agents, and neutral sizing agents. Further, a sizing agent such as a sulfate band or cationized starch may be used in combination with a fixing agent.

Among the above sizing agents, a neutral sizing agent, for example, alkenyl anhydride succinic acid, is used in an electrophotographic image forming apparatus, an inkjet image forming apparatus, or the like from the viewpoint of preservability of a recording medium after an image is formed. It is preferable to use a system sizing agent, an alkyl ketene dimer, an alkenyl ketene dimer, a neutral rosin, a petroleum size, an olefin resin, a styrene-acrylic resin and the like. In addition, as a surface sizing agent, oxidation-modified starch, enzyme-modified starch, polyvinyl alcohol, cellulose-modified products such as carboxymethyl cellulose, styrene-acrylic latex, styrene-maleic acid-based latex, acrylic-based latex, etc. can be used alone. Or can be used in combination.

Further, a paper strength enhancer can be internally or externally added to the paper base material constituting the recording medium of the present invention. Paper strength enhancers include starch, modified starch, vegetable gum, carboxymethyl cellulose, polyvinyl alcohol, modified polyvinyl alcohol, polyacrylamide, styrene-maleic anhydride copolymer, vinyl chloride-vinyl acetate copolymer, and styrene-butadiene. Polymers, polyacrylic acid ester urea-formaldehyde resin, melamine-formaldehyde resin, dialdehyde starch, polyethyleneimine, epoxidized polyamide, polyamide-epicrolhydrin-based resin, methylolated polyamide, chitosan derivative, etc. are mentioned, and these materials are used alone. Alternatively, they can be mixed and used. In addition to this, various auxiliaries such as dyes and pH adjusters, which are blended in ordinary paper media, may be appropriately used.

When producing the recording medium of the present invention, a recording medium having a desired layer structure can be produced by providing a papermaking method and order of the materials constituting the paper base material and, if necessary, a surface layer. For example, after the magnetic material is dispersed and arranged on one side of the paper base material layer prepared by mixing the materials constituting the paper base material such as the pulp fiber described above and making a paper material slurry, the magnetic material is arranged. A paper base material can be produced through a process of laminating another paper base material layer on the surface, and a surface layer can be provided on the surface of the paper base material as needed. In addition, a paper slurry in which a magnetic material is also mixed with a material constituting a paper base material such as pulp fiber is made into paper to prepare a single-layer paper base material, and a surface layer is provided on the surface of the paper base material as needed. Can be provided. Alternatively, a paper base material having a three-layer structure is prepared by laminating a paper base material layer made from paper using a paper material slurry containing no magnetic material on both sides of the paper base material layer containing a magnetic material, and further necessary. A surface layer can be provided on the surface of the paper substrate accordingly. In this way, a paper base material may be produced using the multilayer papermaking, or a recording medium may be produced by further forming a surface layer.

The recording medium of the present invention may have a single-layer structure consisting of only one layer of paper base material, but preferably has two or more layers. In this case, the paper base material itself may be composed of two or more layers, or the paper base material may be provided with surface layers on one side or both sides, and the configuration may be a combination of both. May be good. When the paper substrate is composed of two or more layers, the magnetic material is placed at the interface between the layers to prevent the magnetic material from being exposed on the surface of the recording medium and more inside from the surface of the recording medium. A magnetic material can be contained in the side position. When the paper base material is composed of three or more layers, the magnetic material is contained in or between layers other than the outermost layer of the paper base material so that the magnetic material is located closer to the inner side from the surface of the recording medium. Can be contained. Further, in order to prevent the magnetic material from being exposed on the surface of the recording medium and to contain the magnetic material at a position closer to the inner side from the surface of the recording medium, it is preferable to provide a surface layer, and the paper base material is particularly simple. It is effective when it has a layered structure.

As described above, the layer structure in the thickness direction of the recording medium can be made into a desired structure by appropriately selecting and combining the manufacturing processes. On the other hand, in the recording medium of the present invention, in order to suppress the loss of the magnetic material, the magnetic material is contained in the region of less than 1 mm at the shortest distance from the end of the side parallel to the orientation direction of the pulp fiber. must not. Therefore, when producing the recording medium of the present invention, it is important to control the compounding position of the magnetic material in the plane direction of the recording medium (the direction orthogonal to the orientation direction of the pulp fibers).

For example, the concentration and flow rate of the magnetic material in the paper material slurry discharged from a plurality of nozzles arranged along the direction intersecting the orientation direction of the pulp fibers (moving direction of the papermaking wire) are set for each nozzle. By controlling or adjusting the position of the nozzle tip with respect to the wire width direction, it is possible to control the blending position of the magnetic material in the wire width direction.

As a result, the sheet before carrying out the cutting step contains a magnetic material and pulp fibers oriented in the plane direction of the sheet, forms a band in a direction parallel to the orientation direction of the pulp fibers, and forms the pulp. It is formed alternately in a direction orthogonal to the orientation direction of the fiber, has a first region containing the magnetic material and a second region not containing the magnetic material, and is formed between two adjacent first regions. It is possible to obtain a sheet (large-format dry sheet) having a width of 2 mm or more in the second region, and a specific width and position with respect to the dimensional width of the recording medium to be produced, such as A size series and B size series. It is possible to distribute the magnetic material in the air. When cutting the above-mentioned large-sized dry sheet, the strip-shaped region (first region) containing the magnetic material does not contain the magnetic material so that the shortest distance from the cutting line to the strip-shaped region (first region) containing the magnetic material is 1 mm or more. The recording medium of the present invention can be obtained by cutting the inside (second area). Instead of cutting a large-sized dry sheet, perforations or cut lines are made so that the user can separate or cut along the perforations or cut lines previously made on the sheet. May be used as the recording medium of the present invention.

FIG. 4 is a schematic schematic view showing an example of the sheet of the present invention, in which arrow Y indicates the orientation direction of the pulp fibers, 40 indicates the sheet, 50 indicates the region containing the first magnetic material, and 60 indicates the second magnetic material. The region not included, 62 is a strip-shaped region provided along the end of the side parallel to the arrow Y direction of the sheet 40 and not containing the magnetic material (hereinafter, abbreviated as the region not containing the magnetic material at the end). In the figure, the dotted line Y11-Y12, the dotted line Y21-Y22, the dotted line X11-X12, the dotted line X21-X22, and the dotted line X31-X32 represent the cutting line. The sheet 40 shown in FIG. 4 has a magnetic material-free region 62 at the end, a region 50 containing the first magnetic material, and a th. Areas 60 in which the magnetic material is not contained in 2, the first area 50, the second area 60, the area 50 containing the first magnetic material, and the area 62 not containing the magnetic material at the end are formed in this order. The width of the region 60 not containing the second magnetic material in the direction of the code X21-X22 is 2 mm or more, and the width of the region 62 not containing the magnetic material at the end in the direction of the code X21-X22 is 1 mm or more. When the sheet 40 is cut to obtain a recording medium, it is cut along the cutting line indicated by the dotted line in the drawing. Here, the cutting lines Y11-Y12 and Y21-Y22, which are set to divide the region 60 not containing the second magnetic material into two, have a minimum distance of 1 mm or more from these cutting lines to the first region 50. Is set to be.

The papermaking method used in producing the recording medium of the present invention is not particularly limited. For example, a multi-layer paper machine, a conventionally known long net paper machine, a circular net paper machine, a twin wire method, or the like can be used. Either the acidic or neutral papermaking method may be used.

As the method for multi-layer papermaking, any method may be used: circular net multi-cylinder papermaking, long net multi-cylinder, long net / circular net combination, multi-head box, short net / long net method, for example, by Saburo Ishiguro. Any of the methods described in detail in "Latest Papermaking Technology-Theory and Practice" (Papermaking Research Institute, 1984) may be used, or a round net multi-cylinder system in which a plurality of round nets are connected may be used.

When producing the recording medium of the present invention, a coating liquid can be applied to the surface of the paper substrate. As the adhesive contained in the coating liquid, either one or both of water-soluble and water-dispersible polymer compounds are used, and for example, cationic starch, amphoteric starch, oxidized starch, enzyme-modified starch, and thermochemical-modified starch. , Estelized starch, starches such as etherified starch, cellulose derivatives such as carboxymethyl cellulose and hydroxyethyl cellulose, natural or semi-synthetic polymer compounds such as gelatin, casein, soybean protein and natural rubber, polyvinyl alcohol, isoprene, neoprene , Polydienes such as polybutadiene, polyalkenes such as polybutene, polyisobutylene, polypropylene, polyethylene, vinyl halide, vinyl acetate, styrene, (meth) acrylic acid, (meth) acrylic acid ester, (meth) acrylamide, methyl vinyl ether, etc. Vinyl-based polymers and copolymers, synthetic rubber latex such as styrene-butadiene-based and methyl methacrylate-butadiene-based, polyurethane resin, polyester resin, polyamide resin, olefin-maleic anhydride resin, melamine resin and other synthetic polymer compounds Etc. can be used. And from these, it can be used alone or in mixture, but it is not limited to this. However, from the viewpoint of manufacturing cost, it is preferable to use starch, which is cheaper.

Examples of pigments contained in the coating liquid include heavy calcium carbonate, light calcium carbonate, kaolin, calcined kaolin, structural kaolin, delamikaolin, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, alumina, and magnesium carbonate. , Magnesium oxide, silica, magnesium aluminosilicate, fine-grained calcium silicate, fine-grained magnesium carbonate, fine-grained light calcium carbonate, white carbon, bentonite, zeolite, sericite, smectite and other mineral pigments, polystyrene resin, styrene-acrylic Both Examples thereof include polymerized resins, urea resins, melamine resins, acrylic resins, vinylidene chloride resins, benzoguanamine resins, their fine hollow particles, and through-hole type organic pigments, and one or more of these are used.

The blending ratio of the adhesive to the pigment in the coating liquid is preferably in the range of 5 to 50 parts by mass with respect to 100 parts by mass of the pigment. If the mixing ratio of the adhesive to 100 parts by mass of the pigment is less than 5 parts by mass, there is a problem that the coating film strength of the surface layer is low and paper dust is generated. Further, if the blending ratio of the adhesive to 100 parts by mass of the pigment exceeds 50 parts by mass, there is a problem that the adhesive is excessive, the cost is increased, and the practicality is low.

The resin used for the surface layer is not particularly limited as long as it is a known thermoplastic resin. For example, a resin having an ester bond; a polyurethane resin; a polyamide resin such as a urea resin; a polysulfone resin; a polyvinyl chloride resin, Polyvinylidene chloride resin, vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-vinyl propionate copolymer resin; polyol resin such as polyvinyl butyral, ethyl cellulose resin, cellulose resin such as cellulose acetate resin; polycaprolactone resin, styrene- Maleic anhydride resin, polyacrylonitrile resin, polyether resin, epoxy resin, phenol resin; polyethylene resin, polypro Examples thereof include polyolefin resins such as pyrene resin, copolymer resins of olefins such as ethylene and propylene and other vinyl monomers, and acrylic resins.

From the viewpoint of high film-forming ability, the coating liquid contains polyvinyl alcohol with a saponification degree of 90 mol% or more, modified polyvinyl alcohol, styrene-maleic anhydride copolymer, vinyl chloride-vinyl acetate copolymer, and styrene-. It is preferable to use a butadiene copolymer, a polyacrylic acid ester, or the like.

In the coating liquid, various auxiliary agents such as surfactants, pH adjusters, viscosity adjusters, softeners, gloss imparting agents, dispersants, flow modifiers, conductivity inhibitors, stabilizers, and antistatic agents are further added. Add agents, cross-linking agents, antioxidants, sizing agents, optical brighteners, colorants, UV absorbers, defoamers, water resistant agents, plasticizers, lubricants, preservatives, fragrances, etc. as needed. It is also possible to do.

A coating device generally known as a method for applying a coating liquid onto a paper substrate in order to form the surface layer, for example, a size press, a blade coater, an air knife coater, a roll coater, a reverse roll coater, a bar coater, and a curtain. A coater, a die coater, a gravure coater, a champlex coater, a brush coater, a two-roll or metering blade type size press coater, a bill blade coater, a short dwell coater, a gate roll coater, or the like can be appropriately used.

By applying the coating liquid to the surface of the paper substrate by the coating method, a surface layer can be formed on the surface of the paper substrate. The amount of coating liquid processed per side of the paper substrate is 0.3 to 20 g / m per side in terms of dry mass.²Is preferably in the range of 0.3 to 8 g / m²The range of is more preferable, and considering the cost, 0.6 to 3.0 g / m²Is more preferable. Processing amount is 0.3g / m²If it is less than the above, the strength of the surface of the recording medium becomes insufficient, and the magnetic material existing in the vicinity of the surface may be missing. Processing amount is 20g / m²If it is larger than that, it becomes sticky especially in a high humidity environment and may cause a transfer defect when the recording medium is conveyed in the image forming apparatus.

When the surface layer is provided on the surface of the paper base material, it can be formed on one side or both sides of the recording medium. Further, the surface layer may be composed of only one layer, but may have a multi-layer structure including two or more layers. When forming surface layers on both sides of the recording medium or forming a surface layer having a multi-layer structure, the amount and composition of the coating liquid used to form each surface layer do not have to be the same, which is desired. It can be selected as appropriate according to the quality level of. When forming the surface layer, it is preferable to provide the surface layers on both sides of the recording medium from the viewpoint of preventing curling.

When the recording medium of the present invention has a surface layer, it is preferable to form the surface layer and then perform a smoothing treatment using a smoothing treatment device such as a super calendar, a gloss calendar, or a soft calendar. Further, smoothing may be appropriately performed on-machine or off-machine, and the form of the pressurizing device, the number of pressurizing nips, heating and the like can be appropriately adjusted according to the normal smoothing process.

On the other hand, as a method of dispersing and arranging the magnetic material between the two paper base layers, after providing an adhesive layer on one side of at least one paper base layer, the magnetic material is independently sprayed on the adhesive layer. Then, the other paper base layer is attached to the surface on which the magnetic material is placed, or an adhesive in which the magnetic material is dispersed in advance is applied to one side of one paper base layer, and then the other paper base is applied. Examples include a method of laminating material layers. After the paper base material layers are bonded together in this way, a surface layer can be formed if necessary.

Examples of the adhesive used for the adhesive layer include water-based and solvent-based adhesives (specifically, starch, modified starch, PVA, carboxymethyl cellulose, urethane-based, polyester-based, epoxy-based, rubber-based, and cyanoacrylate-based adhesives. , An emulsion-based adhesive or the like can be used, and it is particularly preferable to use a polyester-based adhesive from the viewpoint of safety.) In addition to the coating, a double-sided tape can also be used.

Further, the surface resistivity of the recording medium of the recording medium of the present invention is not limited to a certain value, but when an image is formed by an electrophotographic method, it is preferable that the surface resistivity of the recording medium is satisfied with the characteristics required for an electrophotographic transfer paper. , Surface resistivity is 1 × 10⁹Ω / ~ 5 × 10¹¹It is preferably in the range of Ω / . This surface resistivity is measured by performing measurements in accordance with JIS K 6911 in the pretreatment and measurement environment specified in JIS P8111.

In order to adjust the surface resistivity, inorganic substances such as sodium chloride, potassium chloride, calcium chloride, sodium sulfate, zinc oxide, titanium dioxide, tin oxide, aluminum oxide, magnesium oxide, alkyl phosphate ester acid, alkyl sulfate ester, etc. Conductive agents such as organic materials such as acids, sodium sulfonic acid salts, and quaternary ammonium salts can be used, and by adjusting the type of conductive agent and the amount added to the paper substrate, the recording medium can be used. The surface resistivity can be controlled to a desired value. From the viewpoint of environmental protection, it is desirable to use a non-halogen-based conductive agent such as sodium sulfate as the conductive agent.

The basis weight of the recording medium of the present invention (JIS P 8124) is not particularly specified, but is preferably 60 g / m.²It is desirable that it is the above. Basis weight is 60g / m²Below, the strain of the recording medium tends to be small. Therefore, when an image is formed by an electrophotographic image forming apparatus, the recording medium may be wound around a fixing member such as a heating roll constituting the fixing device for fixing the toner image transferred to the surface of the recording medium, or the fixing member. Image defects may occur due to poor peeling between the image and the recording medium. Similarly, the basis weight is 60 g / m.²If it is less than the above value, the magnetic material contained in the recording medium may be easily exposed to the surface, or the magnetic material may be easily removed from the surface of the recording medium. In addition, when an image is formed by an electrophotographic method, an inkjet method, or the like, the magnetic material is easily visible on the surface of the recording medium, so that the appearance of the image may be deteriorated.

Further, the recording medium of the present invention has a product moisture content within an appropriate range immediately after being opened from a state sealed by a moisture-proof package, specifically preferably 3 to 6.5% by mass, more preferably 4.5 to 5.5% by mass. It is preferable to adjust the water content with a paper machine or the like when the paper substrate is made so that it falls within the range of about%. In addition, the produced recording media should be wrapped in a predetermined number of sheets using a moisture-proof wrapping paper such as polyethylene laminated paper or a material such as polypropylene film so that moisture absorption and dehumidification do not occur during storage of the produced recording medium. Is desirable.

Next, regarding the formation of an image using the recording medium of the present invention, an electrophotographic image formation will be described as an example. FIG. 5 is a schematic schematic view showing an example of an electrophotographic image forming apparatus. As shown in FIG. 5, the image forming apparatus 10 is an image holder in which an electrostatic latent image is formed by being rotated in a predetermined direction. It has twelve. A charging device 14, an exposure device 16, a developing device 18, a transfer device 22, and a cleaning device 24 are arranged in this order in the vicinity of the image holder 12 along the rotation direction of the image holder 12. Further, the image forming apparatus 10 includes a control unit (not shown) for controlling various devices included in the image forming apparatus 10.

The transfer device 22 is composed of a roll-shaped member, and is arranged so as to be in pressure contact with the image holder 12. Further, the recording medium 20 transported to the pressure contact portion (transfer portion) between the transfer device 22 and the image holder 12 by a transport means (not shown) moves the transfer portion in a direction that coincides with the rotation direction of the image holder 12. Can pass. Further, in the transport direction of the recording medium 20, fixing is arranged so as to contact and press each other on the downstream side of the recording medium 20 in the transport direction from the transfer unit, and at least one of them has a pair of fixing rolls 27 having a built-in heating source. The device 26 is provided, and the recording medium 20 that has passed through the transfer portion can pass between the pair of fixing rolls 27 (pressure contact portion).

The charging device 14 uniformly charges the surface of the image holder 12. The exposure device 16 scans and exposes a laser beam modulated according to image data input from an external device (not shown) via an input / output unit (not shown) via a wired or wireless communication onto the image holder 12. Form an electrostatic latent image on the image holder 12. The developing device 18 develops an electrostatic latent image formed on the image holder 12 with toner to form a toner image on the image holder 12. The transfer device 22 sandwiches and conveys the recording medium 20 to and from the image holder 12, and records a toner image formed on the image holder 12 by applying a transfer voltage by a power source (not shown). Transfer to medium 20. The cleaning device 24 removes residual toner on the image holder 12. The fixing device 26 fixes the toner image transferred on the recording medium 20 on the recording medium 20.

The fixing device 26 fixes the toner image on the surface of the recording medium 20 by heating and pressurizing the recording medium 20 on which the toner image passing through the pressure contact portion is transferred. It is preferable that the fixing is performed by oilless fixing. Oilless fixing is a fixing method in which the surface of the fixing roll 27 is fixed without containing a mold release agent such as oil. When oilless fixing is performed, the fixing device 26 does not have to have a supply device for supplying a release agent to the surface of the fixing roll 27.

As the toner used for forming an image, a known toner can be used, and usually, a toner containing a colorant and a binder resin such as a polyester resin or a styrene-acrylic resin can be used. When oilless fixing is performed, a mold release agent is also contained in the toner. The method for producing the toner used is not particularly limited, and known production methods such as a pulverization method and a polymerization method can be used.

In image formation, first, the surface of the image holder 12 is uniformly charged by the charging device 14, and then the laser beam is scanned and exposed by the exposure device 16. An electrostatic latent image is formed on the surface of the image holder 12 by scanning exposure of laser light. The electrostatic latent image formed on the image holder 12 is developed by the developing device 18 when the rotation of the image holding body 12 reaches the region facing the installation position of the developing device 18. By the development by the developing apparatus 18, a toner image corresponding to the electrostatic latent image is formed on the image holder 12 (hereinafter, referred to as a developing step).

The recording medium 20 is supplied from the recording medium storage unit (not shown) to the transport path (not shown) in the image forming apparatus 10 by a transport device such as various transport rolls (not shown), and is transferred to the image holder 12 and transferred. It is conveyed to the pressure contact portion (transfer portion) with the device 22. When the toner image forming region on the surface of the image holder 12 reaches the transfer portion and the recording medium 20 is sandwiched and conveyed between the image holder 12 and the transfer device 22, the toner image on the image holder 12 is conveyed. Is transferred to the recording medium 20.

The transfer of the toner image to the recording medium 20 is performed by applying a voltage to the roll-shaped transfer device 22 by a power source (not shown). When a voltage is applied to the transfer device 22, an electric field that causes each toner constituting the toner image formed on the image holder 12 to move in the direction of the recording medium 20 is generated between the image holder 12 and the transfer device. The toner image formed between 22 and the image holder 12 is transferred to the recording medium 20 (hereinafter referred to as a transfer step).

The toner image transferred to the recording medium 20 is conveyed to the fixing device 26 by a conveying means (not shown), fixed on the recording medium 20 by the fixing device 26 (hereinafter referred to as a fixing step), and transferred to the recording medium 20. An image is formed. The recording medium 20 on which the image is formed is discharged to the outside of the image forming apparatus 10 by a discharge roll (not shown).

Hereinafter, the present invention will be described in more detail with reference to examples, but of course, the scope of the present invention is not limited thereto. (Example 1) Light calcium carbonate (Tamapearl TP-121) as a filler in a pulp slurry containing 85 parts by mass of LBKP (bleached kraft pulp) and 15 parts by mass of NBKP (bleached softwood kraft pulp) with respect to 100 parts by mass of pulp solids. , Okutama Kogyo Co., Ltd.) 3 parts by mass, cationized pulp (trade name: MS4600, Nippon Food Chemical Industry Co., Ltd.) 0.10 parts by mass, and alkenyl succinic anhydride (Fiblanc 81, Japan NSC) 0.05 Mass parts were added.

A paper slurry having a solid content concentration of 0.4% was prepared by diluting these mixtures with white water. This paper slurry is 40g / m using an oriented sheet former (manufactured by Kumagai Riki Kogyo Co., Ltd., trade name ORIENTED SHEET FORMER) under the following papermaking conditions.²Two Wet sheets with the same basis weight were made. &lt;Papermaking conditions&gt; Papermaking wire speed 1200m / min Sample injection pressure 1kgf / cm² 7 strokes

Next, a magnetic material (composition: Fe-Co-Si) having a diameter of 30 μm and a length of 30 mm was placed on the surface of one sheet. The magnetic material should be located in a region 1.5 mm or more away from the end of the side parallel to the MD direction of the sheet in the direction perpendicular to the orientation direction of the pulp fibers when the final cutting position is used as a reference. It was placed on the surface of the sheet. After that, another sheet is superposed on the surface on which the magnetic material is placed, and the laminate of these two sheets is 5 kgf / cm by a square sheet machine press (manufactured by Kumagai Riki Kogyo Co., Ltd.).²After pressing for 10 minutes at the same pressure, dry with a rotary dryer (manufactured by Kumagai Riki Kogyo Co., Ltd., trade name ROTARY DRYER DR-200) under the conditions of drum temperature 100 ° C and rotation speed 120 cm / min, and after cutting. , A4 size paper substrate was obtained.

Next, on both sides of the prepared paper base material, 0.6 g / m of oxidized starch (Ace A, manufactured by Oji Cornstarch Co., Ltd.) was added by dry weight per side of the paper base material.², Polyvinyl alcohol (PVA-117, manufactured by Kuraray) with a degree of saponification of 99 mol% is 0.05 g / m², And sodium sulfate 0.1 g / m²A coating liquid mixed with these was applied by a size press device and dried. In addition, a calendar device is used to smooth the surface so that the Oken-style smoothness is 50 seconds, and the basis weight is 80 g / m.²I got the recording medium of.

The minimum value of the shortest distance between the end of the side parallel to the orientation direction of the pulp fibers of the obtained recording medium and the magnetic material is 1.5 mm, and the minimum value of the shortest distance between the surface of the recording medium and the magnetic material is 30 μm. there were. The basis weight was measured by the method of JIS P 8124.

(Example 2) In Example 1, when the magnetic material is placed on one of the sheet surfaces, the orientation direction of the pulp fibers is defined when the magnetic material is placed from the end of the side parallel to the MD direction of the sheet with reference to the final cutting position. A recording medium was prepared in the same manner as in Example 1 except that the sheet surface was arranged so as to be located in a region separated by 1.0 mm or more in the direction perpendicular to the sheet.

(Example 3) In Example 1, when arranging the magnetic material on one sheet surface, the magnetic material is applied from the end of the side parallel to the MD direction of the sheet to the final cutting position with respect to the orientation direction of the pulp fibers. A recording medium was prepared in the same manner as in Example 1 except that the sheet surface was arranged so as to be located in a region separated by 10 mm or more in the perpendicular direction.

(<u style="single">reference</u>Example 4) Light calcium carbonate (Tamapearl TP-121) as a filler in a pulp slurry containing 85 parts by mass of LBKP (bleached kraft pulp) and 15 parts by mass of NBKP (bleached softwood kraft pulp) with respect to 100 parts by mass of pulp solids. , Okutama Kogyo Co., Ltd.) 3 parts by mass, cationized pulp (trade name: MS4600, Nippon Food Chemical Industry Co., Ltd.) 0.10 parts by mass, and alkenyl succinic anhydride (Fiblanc 81, Japan NSC) 0.05 Mass parts were added.

A paper slurry having a solid content concentration of 0.4% was prepared by diluting these mixtures with white water. This paper slurry is 10g / m using an oriented sheet former (manufactured by Kumagai Riki Kogyo Co., Ltd., trade name ORIENTED SHEET FORMER) under the following papermaking conditions.²We made two Wet sheets (first sheet) with the same basis weight. &lt;Papermaking conditions&gt; Papermaking wire speed 1200m / min Sample injection pressure 1kgf / cm² 2 strokes

A paper slurry containing 2.5 parts by mass of the magnetic material used in Example 1 was prepared with respect to 100 parts by mass of the paper slurry used to prepare the first sheet. Next, this paper slurry was applied to 60 g / m using an oriented sheet former (manufactured by Kumagai Riki Kogyo Co., Ltd., trade name ORIENTED SHEET FORMER) under the following papermaking conditions.²We made one sheet of Wet sheet (second sheet) with the basis weight of. &lt;Papermaking conditions&gt; Papermaking wire speed 1200m / min Sample injection pressure 1kgf / cm² 11 strokes

Next, the second sheet and the first sheet are laminated in this order on one side of the first sheet, and the laminated body of these three sheets is pressed under the same conditions as in Example 1. After drying, the medium was cut into A4 size and pressed for size to prepare a recording medium. Among the obtained recording media, those in which the magnetic material is at a position of 1 mm or more in the direction perpendicular to the orientation direction of the pulp fibers when the final cutting position is used as a reference from the end of the side parallel to the MD direction. Sorted.

(Example 5) In Example 1, the papermaking conditions of the Wet sheet were changed to the conditions shown below, a magnetic material (composition: Fe-Co-Si) with a diameter of 20 μm and a length of 290 mm was used as the magnetic material, and the magnetic material was placed on one sheet surface. The magnetic material is located in a region 2 mm or more away from the end of the side parallel to the MD direction of the sheet in the direction perpendicular to the orientation direction of the pulp fibers when the final cutting position is used as a reference. A recording medium was prepared in the same manner as in Example 1 except that it was arranged on the surface of the sheet as described above. The basis weight of the Wet sheet obtained under the following papermaking conditions is 45 g / m.²Met. &lt;Papermaking conditions&gt; Papermaking wire speed 1200m / min Sample injection pressure 1kgf / cm² 7 strokes

(Comparative example 1) In Example 1, when the magnetic material is placed on one of the sheet surfaces, the orientation direction of the pulp fibers is defined when the magnetic material is placed from the end of the side parallel to the MD direction of the sheet with reference to the final cutting position. A recording medium was prepared in the same manner as in Example 1 except that the sheet surface was arranged so as to be located in a region separated by 0.5 mm or more in the direction perpendicular to the sheet.

(Comparative example 2) The number of strokes when making the first sheet is one, and the basis weight is 7 g / m.²Except for changing to<u style="single">reference</u>A recording medium was prepared in the same manner as in Example 4. Among the obtained recording media, there is a magnetic material at a position 0.5 to 0.6 mm in the direction perpendicular to the orientation direction of the pulp fibers from the end of the side parallel to the MD direction with respect to the final cutting position. I sorted out the ones.

(Comparative example 3) In Example 1, the papermaking conditions of the Wet sheet were changed to the conditions shown below, a magnetic material (composition: Fe-Co-B) with a diameter of 20 μm and a length of 290 mm was used as the magnetic material, and the magnetic material was placed on one sheet surface. The magnetic material is located in a region 0.5 mm or more away from the end of the side parallel to the MD direction of the sheet in the direction perpendicular to the orientation direction of the pulp fibers when the final cutting position is used as a reference. A recording medium was prepared in the same manner as in Example 1 except that the sheet was arranged on the surface of the sheet. The basis weight of the Wet sheet obtained under the following papermaking conditions is 45 g / m.²Met. &lt;Papermaking conditions&gt; Papermaking wire speed 1200m / min Sample injection pressure 1kgf / cm² 7 strokes

(Comparative example 4) In Example 1, when the magnetic material is placed on one of the sheet surfaces, the orientation direction of the pulp fibers is defined when the magnetic material is placed from the end of the side parallel to the MD direction of the sheet with reference to the final cutting position. A recording medium was prepared in the same manner as in Example 1 except that it was arranged on the sheet surface so as to be located at 0 mm in the direction perpendicular to the sheet (so that the magnetic material was exposed at the edge after cutting).

-Evaluation- The recording media of each Example and Comparative Example were subjected to an image formation test using an electrophotographic image forming apparatus. When DocuCentreColor f450 (manufactured by Fuji Xerox Co., Ltd.) is used as the image forming apparatus, the fixing condition is set to the plain paper mode (conveying speed 160 mm / s), and 2000 halftone images are continuously formed on the entire surface of the recording medium. We evaluated the lack of magnetic material, image quality defects, and transport defects. The results are shown in Table 1.

<tables num="1"><img file="JP4916239B2_D0001.tif" /></tables>

The lack of magnetic material, image quality defects, and transport defects shown in Table 1 were evaluated according to the following criteria. [Lack of magnetic material] The lack of magnetic material was evaluated by visually observing the amount of magnetic material adhering to and deposited on the paper feed roll, transfer belt cleaner, and fixing roll in the apparatus after forming 2000 halftone images, and evaluating them according to the following criteria. : No lack of magnetic material is confirmed. : Almost no lack of magnetic material is confirmed. Δ: There are some gaps in the magnetic material, which poses a practical problem. ×: Significant lack of magnetic material is confirmed.

[Image quality defect] Image quality defects are evaluated by sampling the image (near the 2000th sheet) immediately before the end of the halftone image formation test, visually observing the presence or absence of image defects such as streaks and omissions due to the lack of magnetic material, and evaluating them according to the following criteria. did. : No image defects are found in the sample. Δ: Slight image defects are observed in the sample. X: Image defects are observed in the sample.

[Transport failure] The transfer defects were evaluated by counting the number of occurrences of transfer defects such as misfeeds during the continuous halftone image formation test of 2000 images and evaluating them according to the following criteria. : No transport failure. Δ: Transport failure occurred 1 or more and less than 5 times ×: Transport failure occurred 5 times or more

<figref num="1">It is a schematic schematic diagram for demonstrating the measurement method of the shortest distance between a magnetic material existing near the end portion of the side parallel to the orientation direction of a pulp fiber, and the end portion.</figref><figref num="2">It is a schematic schematic diagram for demonstrating the method of measuring the shortest distance between a recording medium surface and a magnetic material.</figref><figref num="3">It is explanatory drawing which shows the large Barkhausen effect.</figref><figref num="4">It is a schematic schematic diagram which shows an example of the sheet of this invention.</figref><figref num="5">It is a schematic schematic diagram which shows an example of an electrophotographic image forming apparatus.</figref>

Code description

10 Image forming device 12 image holder 14 Charging device 16 Exposure device 18 Developer 20 Recording medium 22 Transfer device 24 Cleaning equipment 26 Fixing device 27 Fixing roll 40 sheets 50 Region containing the first magnetic material 60 Region not containing the second magnetic material 62 A strip-shaped area that does not contain magnetic material and is provided along the edge of the side parallel to the arrow Y direction of the sheet 40. 100 Recording medium 102 Recording medium cross section 110 end 112 Recording medium surface 120, 120A, 120B, 120C magnetic material