JPH11277729A - Recording medium and inkjet recording method - Google Patents

Abstract

(57) [Summary] [Problem] Even if a base paper having a watermark pattern is used, ink absorption and ink absorption capacity are good, bleeding and feathering do not occur, and excellent design and anti-counterfeiting properties are obtained. A recording medium capable of forming a high-quality image, and an ink jet recording method using the recording medium. SOLUTION: A recording medium characterized in that an ink receiving layer containing a pigment is provided on at least one surface of a base paper containing kenaf pulp and on which a watermark pattern is formed, and an ink jet recording method using the recording medium .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording medium which retains the natural texture of kenaf paper and has excellent design and image characteristics, and records ink by flying ink droplets using the recording medium. To an inkjet recording method.

[0002]

2. Description of the Related Art Ink-jet recording is a method in which fine droplets of ink are made to fly and adhere to a recording medium such as paper according to various operating principles to record images, texts, and the like. It has features such as operation with noise, easy multi-coloring, high flexibility of the recording pattern, and no development and fixing step. In recent years, it has been widely used not only for recording monochrome images composed of various figures including characters but also for recording full-color images. In addition, it is used not only for office equipment but also for various purposes such as industrial or art work creation, and is rapidly spreading.

[0003] The main constituent materials of the recording medium used in the ink jet recording system include not only so-called plain paper such as copy paper and bond paper made of ordinary wood pulp, but also various types of paper having an image forming layer on the surface. Various types are used, such as coated paper, transparent films for OHP made of synthetic resin, and fabrics formed of various fibers. Among these, the use of plain paper has been remarkably increased with the spread of personal computers in recent years and the OA of office work.

Accordingly, the recording medium used in the ink jet recording system also requires high-speed absorption and high absorption capacity of ink, improvement in image density and print quality when printing, and improvement in water resistance of printed matter. Etc. are being required. In response to such a request,
JP-A-55-51583 discloses that a coating layer composed of amorphous silica and a polymer binder exhibits high ink absorbency for printing with an aqueous ink and is suitable for high-speed printing. Therefore, it seems effective to apply such a coating layer as an ink receiving layer of an inkjet recording medium.

[0005]

With the above-mentioned conventional recording medium using plain paper as a base paper, a so-called watermark pattern is formed on the base paper for the purpose of imparting a sense of quality, design, or forgery prevention. Is thought to be. However, in the case where plain paper is used as the base paper, if a watermark pattern is formed, the watermark pattern is formed by a change in the fiber density of the base paper. When the ink is applied to the surface of the ink receiving layer having a small amount of ink, the absorption of the ink is performed in the base paper portion. Therefore, the ink absorption speed and the ink absorption capacity are changed depending on the density difference of the pulp forming the watermark pattern. This causes a problem that density unevenness and bleeding occur in the formed image.

Accordingly, the present invention has a high ink absorption and ink absorption capacity, does not cause bleeding or feathering, and is excellent in design and anti-counterfeiting even when a base paper having a watermark pattern is used. An object of the present invention is to provide a recording medium capable of forming a high-quality image and an inkjet recording method using the recording medium.

[0007]

The above object is achieved by the present invention described below. That is, the present invention provides a recording medium comprising a kenaf pulp and an ink-receiving layer containing a pigment provided on at least one surface of a base paper on which a watermark pattern is formed, and an inkjet using the recording medium. Provide a recording method. According to the present invention, when a base paper containing kenaf pulp is used as a base paper of a recording medium, even if an arbitrary watermark pattern is formed on the base paper in advance, the ink absorption and the ink absorption capacity are good and bleeding occurs. There is provided a recording medium which does not cause any feathering and is capable of forming a high-quality image excellent in design property, anti-counterfeiting property and the like. It is considered that such an effect is due to the fact that kenaf paper is significantly bulkier than plain paper, and the ink absorption speed and ink absorption capacity are extremely large.

[0008]

Next, the present invention will be described in detail with reference to preferred embodiments. First, the base paper used in the present invention will be described. The base paper is made of kenaf pulp,
Any one may be used as long as it is contained. Accordingly, kenaf pulp alone may be used as a pulp raw material, or kenaf pulp and another type of pulp such as wood pulp may be used. Kenaf consists of a wood part and a bast part, but the characteristics of the wood part and the bast part are slightly different.Wood pulp consisting of the wood part has a short fiber and a large amount of lignin, whereas a bast part Bast pulp consisting of is long in fiber and low in lignin. When the woody part and the bast part are pulped together, the resulting pulp has properties in between.

In the present invention, any kenaf pulp can be used, but it is particularly preferable to use kenaf pulp in which bast pulp is appropriately added to woody pulp according to desired characteristics. That is, when woody chemical pulp using only the woody part of kenaf as a raw material is used, the obtained base paper has poor air permeability, and particularly when the recording medium of the present invention is used as an ink jet recording paper, the ink has an ink. Tends to be insufficiently absorbent.

The base paper used in the present invention comprises kenaf pulp as described above.
The amount of kenaf pulp is 10% by weight to 100% by weight, more preferably 30% by weight, based on the total pulp constituting the base paper.
It is preferable to use one in the range of 100% by weight.
That is, if the amount of kenaf pulp in the base paper is less than 10% by weight, kenaf paper having a kenaf peculiar texture and color is impaired, which is not preferable.

Examples of the pulp that can be used together with the kenaf pulp at this time include, for example, ordinary pulp mainly composed of conifers such as Akamatsu, Kuromatsu, Ezomatsu, Todomatsu and cedar, and broadleaf trees such as beech, hippopotamus and Shinoki. Can be Further, those obtained by pulping them by any method may be used. For example, groundwood pulp, sulfite pulp, kraft pulp, semi-chemical pulp, chemical ground pulp, refiner ground pulp and the like can be used. Further, used paper pulp obtained by recycling can also be used. Further, in the recording medium of the present invention, in addition to these cellulose fibers, inorganic fibers such as glass fibers or synthetic fibers such as polyester fibers and aramid fibers can be used as needed. In the present invention, a base paper can be formed by using the above-mentioned materials singly or in combination with kenaf pulp by appropriately selecting a plurality of materials from these materials depending on the use of the recording medium.

The base paper used in the recording medium of the present invention can be formed by the same method as that for producing paper made of ordinary wood pulp, except that kenaf pulp is used as its raw material. In addition, a method of forming a watermark pattern on the kenaf paper formed in this manner is, for example, a paper making net attached with a pattern or character pattern made of a thin metal wire, bamboo blind, synthetic resin, or the like at the time of paper making, or a pattern form. In this method, a papermaking net having a mesh filled with a resin or the like is attached as a top net of a round cylinder of a round paper machine or a dandy roll of a fourdrinier paper machine to form paper. In the former case, the mesh of the pattern-shaped portion is closed, and the passage of the stock is suppressed. As a result, since the paper layer in that portion becomes thinner, a watermark pattern appears, and in the latter case, the fibers are pushed away by the convex portion of the pattern shape, and the watermark pattern appears due to the thinner paper layer in that portion. . The watermark pattern may be formed by any other known method.

The base paper used in the present invention may be any of various types of pulp materials including kenaf pulp described above, which are added for the purpose of improving paper flexibility, surface smoothness, opacity, printability and the like. Various internal sizing agents for imparting resistance to liquids such as fillers and inks, fixing agents for fixing these sizing agents, and, if necessary, paper strength agents and retention agents After internally adding an antifoaming agent, a conductive agent, a dye, and the like, the paper can be formed by a conventionally known paper machine.

Examples of the filler that can be used in preparing the base paper include inorganic fillers composed of inorganic pigments such as clay, talc, light calcium carbonate, calcined kaolin, aluminum oxide, aluminum hydroxide, and titanium oxide. No. As the internal sizing agent, a rosin-based sizing agent that has been widely used can be used. In this case, a sulfate band is added as a fixing agent.
When a neutral sizing agent such as an alkyl ketene dimer or alkenyl succinic acid is used, it is used together with a cationic fixing aid such as a cationic starch. Further, as the paper strength enhancer, polyacrylamide-based polymers, starch and the like can be used.

Further, in addition to the internal sizing described above, the base paper used in the present invention may be subjected to a surface sizing treatment by applying a chemical (surface sizing agent) to the surface of the paper, if necessary, in a paper machine. Is also good. As the surface sizing agent in this case, rosin-based, petroleum resin-based, oxidized starch, acetylated starch, starch such as hydroxyethylated starch and derivatives thereof,
Polyvinyl alcohol and its derivatives, alkyd resins,
Examples include synthetic resin systems such as polymers such as polyamide, styrene, acrylic, olefin, maleic acid, and vinyl acetate or copolymers thereof, and emulsion systems and wax systems of these synthetic resins.

The kenaf pulp component of the base paper used in the present invention as described above is preferably a mixture of kenaf wood and bast. The recording medium of the present invention has a thickness of 50 to 250 μm and a basis weight of 50 to 250 m.
It is preferred to use a base paper in the range ² / g. The base paper used in the present invention has a disintegration freeness of 150 to 600 m.
It is preferably 1. When adjusting the thickness and surface smoothness of the base paper used in the present invention, conventionally known equipment such as a machine calender or a super calender can be used as necessary.

In the present invention, an ink receiving layer is formed on at least one surface of the base paper formed as described above as follows. The ink receiving layer including kenaf pulp formed as described above and provided on at least one surface of the base paper on which the watermark pattern is formed includes at least a pigment, and preferably includes a pigment and a binder. . Examples of pigments that can be used at this time include, for example,
Silica, zeolite, calcium carbonate, diatomaceous earth, kaolin clay, calcined clay, talc, aluminum hydroxide, colloidal alumina, alumina, alumina hydrate,
Examples of the pigment include those conventionally used as coating agents for general coated paper, such as barium sulfate, titanium dioxide, zinc oxide, zinc carbonate, magnesium silicate, magnesium carbonate, and organic pigments (plastic pigments). or,
In the present invention, these pigments can be used alone or in an appropriate mixture of two or more. A particularly preferred pigment is alumina hydrate.

In the present invention, when forming the ink receiving layer of the recording medium, a coating liquid in which these pigments are dispersed is prepared, and the coating liquid is coated on at least one surface of the base paper. In this case, it is preferable that the average particle diameter of the pigment be less than 500 nm in a state where the pigment is dispersed in the coating liquid. Alumina hydrate tends to be in such a state, and in the present invention, alumina hydrate may be used as a pigment constituting the ink receiving layer. Further, among the alumina hydrates having such a particle diameter, the BET specific surface area is 5 to 500 m ² /
More preferably, g of alumina hydrate is used. still,
The average particle size of the pigment is determined by a centrifugal sedimentation method.
The BET specific surface area is determined by a nitrogen adsorption / desorption method.

In the recording medium of the present invention, when the average particle diameter of the pigment in a dispersed state in the coating liquid is larger than 500 nm, the surface which gives an extremely white impression when the ink receiving layer is formed. And the color and texture of the kenaf may be impaired. On the other hand, if the ink receiving layer is formed using a pigment in a dispersed state in the coating liquid having an average particle diameter of less than 500 nm, the color and the texture of the base paper kenaf are impaired by the pigment. Never be.

If alumina hydrates suitable for the present invention, especially alumina hydrates such as X-ray amorphous or boehmite and pseudo-boehmite, gamma alumina and the like are used, for example, acetic acid,
By using a known treating agent such as hydrochloric acid, nitric acid, and formic acid, a coating liquid in which alumina hydrate is dispersed with an average particle diameter of 300 nm or less can be obtained relatively easily. As a result, if the ink receiving layer is formed using the coating liquid, a recording medium can be obtained in which the color and texture of the kenaf paper as the base paper are maintained without loss.

Further, in addition to the above-mentioned advantages, alumina hydrate has a positive charge, and thus is fixed to a dye having a negative charge, which is widely used in inks widely used for ink jet recording and the like. There is an advantage that the property is good. Therefore, if the ink receiving layer is formed by using alumina hydrate, an image having excellent color developability can be formed. Therefore, if alumina hydrate is used as the pigment constituting the ink receiving layer of the recording medium of the present invention, a silica compound conventionally known as a material for the ink receiving layer is used, and a coating layer similar to the conventional one is used. Does not cause problems such as browning of black ink and problems such as light fastness that occur when an ink receiving layer is formed, and especially when a full-color image is formed, compared with a conventional recording medium in terms of image quality. A particularly favorable result is obtained.

The ink receiving layer of the recording medium of the present invention is formed containing at least the above-mentioned pigments. Preferably, these pigments are stably fixed to at least one surface of the base paper. It is preferable to constitute with the binder for the above. As the binder used at this time, for example, polyvinyl alcohol, modified polyvinyl alcohol, polyacrylamide, partially saponified polyvinyl acetate, oxidized starch, etherified starch, cellulose derivatives such as carboxymethylcellulose and hydroxyethylcellulose, casein, gelatin, Soy protein, maleic acid resin, and the like. These may be used alone or in combination of two or more.

In the present invention, a coating liquid containing the binder as described above and a pigment such as alumina hydrate described above is prepared, and a coating liquid containing kenaf pulp and having a watermark pattern is formed using the coating liquid. It is preferable that the ink is applied to at least one surface of the paper and dried to form an ink receiving layer. It is preferable that the compounding ratio of the pigment in the coating liquid at this time is 15 to 90% by weight of the total solids of the formed ink receiving layer. In other words, if the amount is less than 15% by weight, when an image is formed on the formed ink receiving layer, the fixability of the dye in the ink tends to be insufficient, and the resulting image may have reduced print density, feathering, and bleeding. Occurrence is observed, and character quality and image quality are easily impaired. On the other hand, 9
If the content is more than 0% by weight, powder may fall off from the formed ink receiving layer, and when the recording medium of the present invention is applied to an ink jet printer or the like, there may be a problem in transportability. In addition, the surface on which the ink receiving layer is formed tends to be white, and the natural color of kenaf is likely to be impaired.

Further, in the present invention, when a binder is used for forming the ink receiving layer, the compounding ratio of the binder may be 10 to 85% by weight of the total solids of the ink receiving layer on which the binder is formed. preferable.
In other words, when the content exceeds 85% by weight, the ink absorption of the ink receiving layer tends to be impaired due to the formation of a film by the binder. On the other hand, if the content is less than 10% by weight, the binding strength of the ink receiving layer to at least one surface of the base paper is insufficient, and there is a possibility that powder may fall off. However, when alumina hydrate is used alone as a pigment constituting the ink receiving layer, the alumina hydrate is easily applied to at least one surface of the base paper when it is applied to at least one surface of the base paper. While sinking, the natural feel of the base paper is maintained as it is, but in normal use, there is almost no problem of powder falling off the recording medium surface. There is no problem without using a binder. Therefore, in the present invention, the binder is not always essential when forming the ink receiving layer.

In the coating liquid for forming the ink receiving layer, a pigment dispersant,
Printed matter after recording when an image is formed using an aqueous ink such as an antifoaming agent, a coloring agent, an antioxidant, an ultraviolet absorber, a viscosity modifier, a lubricant, a crosslinking agent, and an ink for inkjet recording. A cationic compound, a cationic resin or the like for improving the water resistance of the recording medium is appropriately selected and used in accordance with the production conditions of the recording medium and the required performance such as the printing quality of the obtained printed matter.

Next, a method for forming the ink receiving layer will be described. First, the components of the ink receiving layer described above are uniformly dispersed or dissolved in an aqueous medium by an ordinary method to prepare a coating liquid. As the aqueous medium used at this time, water or a mixed medium of water and an organic solvent is used. As the dispersion method, for example, using a dispersing machine such as a ball mill, an attritor, a sand mill, a homomixer, a microfluidizer (manufactured by Microfluidics), a nanomizer (manufactured by Nanomizer), and uniformly dispersing or dissolving. Is preferred.

The viscosity of the coating liquid prepared as described above varies depending on the coating method, coating apparatus, coating amount and the like used when coating the coating liquid on at least one surface of the base paper. However, in general, it is preferable to adjust and use 30 cps to 1000 cps. If it is lower than 30 cps, it is difficult to apply a predetermined amount of the coating liquid on at least one surface of the base paper, and if it is higher than 1000 cps, the coated surface is not uniform, which is not preferable.

In the present invention, an ink receiving layer is provided on at least one surface of a base paper having kenaf pulp by applying a coating liquid having the above-described structure using a coating apparatus or a size press apparatus. As a coating method, either an on-machine coater or an off-machine coater may be used, and a conventionally known air knife coater, die coater, blade coater, gate roll coater, bar coater, rod coater, roll coater, gravure coater, curtain coater, etc. Can be used. Then, after coating on at least one surface of the base paper, the coating liquid is dried by blowing hot air to form an ink receiving layer. The temperature and the flow rate of the hot air at this time may be appropriately changed depending on the base paper and the coating liquid to be used.
Preferably, the temperature is about 0 ° C. When the temperature is lower than 50 ° C., it takes a long time to dry. On the other hand, when the temperature is higher than 160 ° C., the base paper and the coating liquid tend to be denatured, which is not preferable.

Further, after the coating, a calendering treatment such as a machine calender, a super calender, a soft calender, etc. may be performed to smooth the surface. In the recording medium of the present invention, the ink receiving layer formed on at least one surface of the base paper as described above has a solid content of 1 to 8 g / m 2 when expressed in terms of a solid coating amount (basis weight). ² and more preferably in the range of ² to 6 g / m ^{2 in} solid content. That is,
In the case of a recording medium having an ink receiving layer having a coating amount of less than 1 g / m ² , when an image is formed, the print density tends to be reduced, feathering and bleeding are likely to occur, and character quality and image quality are reduced. There is a tendency for inferior images. In contrast, when a recording medium having an ink receiving layer having a coating amount of more than 8 g / m ² is used, the whiteness of the ink receiving layer surface is increased, and the natural color and texture of kenaf are considerably impaired. In addition, the watermark pattern formed in the base paper may become unclear. In the invention, it is particularly preferable to form the ink receiving layer so that the coating amount is 8 g / m ² or less from the viewpoint of maintaining the color and texture of the kenaf paper.

In many cases, the ink receiving layer constituting the recording medium of the present invention formed as described above is not formed so as to cover at least one surface of the base paper having kenaf pulp, It is formed with the coating liquid partially penetrating into the paper. That is, in the recording medium of the present invention, since a part of the coating liquid is impregnated inside the base paper, the boundary between the ink receiving layer and the base paper is not always clear. For this reason, the color and texture of the ink receiving surface on which the ink receiving layer is formed are not different from the kenaf paper as the base paper.

The recording medium of the present invention can be used for various recording methods. In particular, in the past, it was difficult to say that bleeding or feathering occurred, the print density was low, and the image quality was good. A remarkable effect can be obtained when used in an ink jet recording system using an aqueous ink. In this case, as the ink used in the ink jet recording method, a normal ink including a colorant, a liquid medium, and other additives may be used. As a coloring agent at this time, a direct dye,
Acid dyes, basic dyes, reactive dyes, or water-soluble dyes such as food dyes, etc., as the liquid medium, water, or an aqueous liquid medium using water and various water-soluble organic solvents may be used. it can.

Examples of other recording systems that can use the recording medium of the present invention include, for example, a resin film, a high-density paper, a synthetic paper and a hot-melt ink containing a hot-melt substance, a dye or the like as a main component. A thermal transfer recording method in which a medium coated on a thin base material is heated from the back side, and the ink is melted and transferred. A solid ink jet is used to heat and melt the hot-melt ink to form small droplets and fly and record. Examples include a recording method, an ink-jet recording method using an ink in which an oil-soluble dye is dissolved in a solvent, and a recording method using a photosensitive pressure-sensitive donor sheet using microcapsules containing a photopolymerizable monomer and a colorless or colored dye / pigment. Can be

A common feature of these recording methods is that the ink is in a liquid state during recording. The liquid ink has a property of penetrating or diffusing in the depth direction or the horizontal direction of the ink receiving layer of the recording medium before curing, solidifying or fixing, and the recording medium for these various recording methods is adapted to each method. Requires proper absorption. Therefore, in the recording medium of the present invention, when forming an ink receiving layer, by appropriately selecting a pigment, a binder, and the like, it is possible to form a recording medium having an appropriate absorbency suitable for the various recording methods described above. Good.

Further, the recording medium of the present invention is also used as a recording medium of an electrophotographic recording system widely used in copiers, printers and the like, and a recording system for heating and fixing a toner which is a non-liquid solid recording agent. it can. Further, it can be used as a recording medium for forming characters and images with ordinary writing implements or paints, or as a recording medium for a recording method using a special ink such as a print.

[0035]

EXAMPLES The present invention will be described more specifically with reference to examples and comparative examples below, but the present invention is of course not limited to these examples. In addition, “%” in the text is based on weight unless otherwise specified.

Example 1 The woody part and bast part of Thai kenaf were digested and bleached to obtain 410 ml of Canadian Standard Freeness.
Kenaf stock was obtained. 5% light calcium carbonate (trade name "PC-700", manufactured by Shiraishi Kogyo Co., Ltd.) and sizing agent (trade name "Size Pine K-903," manufactured by Arakawa Chemical Co., Ltd.) 1% and 0.1% of a retention aid (trade name "High Holder 351", manufactured by Kurita Water Industries Ltd.) are added, and the basis weight is 150 g / m.
^The paper was made using a fourdrinier paper machine so as to obtain ² . Next, a paper net having an epoxy resin character pattern attached was used as the upper net of the dandy roll, and pressed against the paper web on the paper sheet to perform transparency, thereby obtaining a base paper having a watermark pattern.

On one side of this base paper, the following composition (in terms of solid content)
Was applied and dried at a ratio of 4.8 g / m ^{2 in} terms of dry solid content to form an ink receiving layer, thereby obtaining a recording medium of the present invention. -1 part by weight of fine particle silica (trade name "Syloid", manufactured by Fuji Silysia Chemical Ltd.)-4 parts by weight of alumina hydrate (trade name "Cataroid-AP", manufactured by Catalyst Kasei Kogyo Co., Ltd.)-Polyallylamine hydrochloride (trade name) “PAA-HCl-3L”, molecular weight 10,000, manufactured by Nitto Bo) 2 parts by weight ・ Polyvinyl alcohol (trade name “PVA117”, manufactured by Kuraray) 3 parts by weight ・ Water 40 parts by weight

Example 2 0.3% by weight of pulp (AS202, manufactured by Nippon PMC) and polyamide epichlorohydrin resin (WS570, manufactured by Nippon PMC) were added to the same kenaf stock as in Example 1.
0.07% and calcium carbonate (PCX-
850) 3% was added, papermaking was performed using a fourdrinier paper machine so that the basis weight was 150 / m ^2, and then a watermark pattern was formed in the same manner as in Example 1 to obtain a base paper. Next, the same coating liquid as in Example 1 was applied and dried at a rate of 4.5 g / m ^{2 in} terms of dry solid content to form an ink receiving layer, thereby obtaining a recording medium of the present invention.

Examples 3 and 4 In the same manner as in Examples 1 and 2, base papers containing kenaf were obtained, respectively. A coating liquid having the following composition (in terms of solid content) was applied to this base paper at a ratio of 5 g / m ^{2 in} terms of dry solid content and dried to form an ink receiving layer, thereby obtaining a recording medium of the present invention. 7.5 parts by weight of alumina (trade name "Alumina Sol 520", manufactured by Nissan Chemical Industries, Ltd.) 1 part by weight of benzalkonium chloride (trade name "G-50", manufactured by Sanyo Chemical Industry Co., Ltd.)-Polyvinyl alcohol ( Product name "PVA117" manufactured by Kuraray Co., Ltd.) 1.5 parts by weight-Water 40 parts by weight

Example 5 40 parts by weight of so-called whole kenaf pulp, 40 parts by weight of softwood bleached kraft pulp (NBKP) and 20 parts by weight of hardwood bleached kraft pulp (LBKP) obtained by digesting the wood and bast of kenaf from Thailand by digestion and bleaching Was mixed, and 1.5 parts by weight of a rosin sizing agent (trade name "SPN700", manufactured by Arakawa Hayashi San Kagaku Co., Ltd.), 0.5 part by weight of starch (trade name "Amicol", manufactured by Nisseki Chemical Co., Ltd.) and a sulfate band 5 parts by weight, freeness of 400 ml and basis weight of 125 g / m by Fourdrinier paper machine
Then, papermaking was performed to obtain No. ^2, and then a watermark pattern was applied in the same manner as in Example 1 to obtain a base paper. The base paper was coated with the same coating liquid as in Example 1 at a rate of 5 g / m ^{2 in} terms of dry solid content and dried to form an ink receiving layer, thereby obtaining a recording medium of the present invention.

Comparative Example 1 The dry solid content of the ink receiving layer in Example 1 was 1
A recording medium of a comparative example was obtained in the same manner as in Example 1 except that the recording medium was changed to 5 g / m ² . Comparative Example 2 The base paper of Example 1 was used as it was (without forming the ink receiving layer) as a recording medium of Comparative Example.

Evaluation The watermark patterns of the recording media of Examples 1 to 5 and Comparative Examples 1 and 2 were visually observed, and were evaluated as ○ if the watermark patterns could be recognized from a practical viewpoint. In addition, printing was performed using an ink jet printer (trade name “BJC430”, manufactured by Canon Inc.), and the medium after printing was visually observed. When the printed portion was touched by hand and ink did not adhere, it was evaluated as ○. When bleeding and feathering did not occur by visual observation, it was evaluated as ○.

[0043]

[Table 1] Table 1 Evaluation results

[0044]

According to the present invention as described above, it has a watermark pattern, has a natural kenaf texture, is free from bleeding and feathering, has a high print density, and is excellent in character quality and image quality. A recording medium capable of inkjet recording can be provided.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI D21H 27/02 C09D 201/00 // C09D 201/00 D21H 1/22 Z

Claims (8)

[Claims] 1. A recording medium characterized in that an ink receiving layer containing a pigment is provided on at least one surface of a base paper containing a kenaf pulp and having a watermark pattern formed thereon. 2. The recording medium according to claim 1, wherein kenaf is contained in the base paper in an amount of 10% by weight to 100% by weight. 3. The recording medium according to claim 1, wherein a cationic substance is contained in the ink receiving layer. 4. A pigment having a BET specific surface area of 5 to 500 m ² /
The recording medium according to claim 1, wherein the recording medium is g of alumina hydrate. 5. The recording medium according to claim 1, wherein a cationic substance is contained in the ink receiving layer. 6. The recording medium according to claim 5, wherein the cationic substance is a quaternary ammonium salt. 7. When the ink receiving layer is represented by a coating amount,
^2. The recording medium according to claim 1, wherein the coating amount is 1 to 8 g / m < ² > in solid content. 8. An ink jet recording method which performs recording using the recording medium according to claim 1.