JP2015013373A - Ink jet recording sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide, at low costs, an ink jet recording sheet which has texture similar to that of coated sheets for general printing and excellent ink absorption and is usable in bookbinding products to be book-bound.SOLUTION: An ink jet recording sheet is obtained by forming an ink receiving layer based on a pigment containing a hollow plastic pigment and a styrene-butadiene latex, on at least one side of base paper, and subjecting the resultant body to a calender treatment, and the ink receiving layer contains a higher fatty acid salt.

Description

  The present invention relates to an inkjet recording paper. More specifically, the present invention relates to an ink jet recording paper having a texture similar to that of a general printing coated paper.

  The ink jet recording system is a system in which ink droplets are ejected from fine nozzles onto a recording paper and adhered to form dots to perform recording. In recent years, technological advances in inkjet printers, inks, and even recording media have made it easier to increase the speed of devices, reduce sound, and form images with high print quality. Yes. On the other hand, in the field of commercial printing, digital information is printed directly on media such as paper without making a plate, and printed on demand that can handle small lots and various types of variable information printing at a relatively low price. A method has been introduced. The ink jet recording system is being introduced even in such a situation. For example, such an ink jet recording method is also used on demand for printing a book that is composed of a plurality of pages such as a book, a magazine, an album, a catalog, and a document. In addition, recently, the application has expanded with the remarkable improvement of the speed and resolution of the equipment, and the ink-jet suitability is also given to the coated paper that has the same texture as the general printing coated paper for offset printing. The demand to do is getting stronger. Furthermore, since it is used for commercial purposes, further cost reduction is strongly demanded.

  However, when printing general printing coated papers using the inkjet printing method, especially when the same resolution and reproducibility as silver halide photographs are required, the general printing coated papers absorb or absorb ink. There is a problem that the print image quality is poor because the property is extremely inferior.

  As a reason for the above, in the manufacturing process of coated paper for general printing, a calendar process is performed to give glossiness and smoothness. However, in the calendar process, roll dirt (dusting) is likely to occur, and the dusting is suppressed. The use of a release agent in the coating layer can be mentioned. Since generally used release agents have water repellency, the water-repellent action of the release agent reduces the ink-jet ink absorbability, leading to poor ink dryness and print quality degradation. .

  On the other hand, in the ink receiving layer of conventional ink jet recording paper, ink absorbency is imparted by using pigments such as alumina, silica, boehmite, etc. as the main component and the pore volume of the coating layer is increased, and printing. Increasing image quality has solved the problem of ink absorption. However, these ink jet recording papers are inferior in texture because they have a lower white paper gloss than general printing coated papers. Furthermore, since alumina, silica, and the like are expensive, they are not suitable for commercial printing fields such as on-demand printing.

  In conventional ink jet recording paper, printing paper using calcium carbonate having an oil absorption amount in a specific range for the coating layer of the ink jet recording paper in order to improve ink water absorption (see, for example, Patent Document 1). ) And printing paper using kaolin clay having a specific range of particle diameters (see, for example, Patent Document 2), etc., are all likely to cause dusting due to calendar processing, resulting in a glossy white paper Inferior. These techniques are intended to give the ink jet recording paper a texture similar to that of coated paper for general printing, but on the other hand, there is a problem that it is impossible to achieve both ink absorbability and white paper gloss. .

JP2008-238612 JP 2004-082464 A

  SUMMARY OF THE INVENTION An object of the present invention is to provide an ink jet recording paper having a texture similar to that of coated paper for general printing, excellent in ink absorbability, and usable for bookbinding products at low cost.

  The present inventors have suppressed the dusting of the calendar process during the manufacturing process as a cause of inferior ink water absorption and ink drying properties when the same texture as that of general printing coated paper is applied to inkjet recording paper. We paid attention to the mold release agent used for this purpose. In addition, as a result of intensive studies to solve the above problems, the present inventors have added a higher fatty acid salt to the ink receiving layer mainly composed of a pigment containing a hollow plastic pigment and a styrene butadiene latex, It has been found that by reducing the amount of the release agent used, both the dusting suppression of the calendar process and the ink absorptivity can be achieved and the above problems can be solved, and the present invention has been completed.

  That is, the ink jet recording paper according to the present invention is an ink jet recording paper obtained by calendering an ink receiving layer mainly composed of a pigment containing a hollow plus chip pigment and styrene budadiene latex on at least one side of a base paper. The ink-receiving layer contains a higher fatty acid salt. With such a configuration, it is possible to obtain an ink jet recording paper excellent in absorbency and white paper gloss while having a dusting prevention effect in calendar processing.

  In the ink jet recording paper according to the present invention, the content of the higher fatty acid salt in the ink receiving layer is preferably 0.05 to 5 parts by mass with respect to 100 parts by mass of the pigment. A more excellent dusting effect and ink absorbability can be maintained.

  Further, in the ink jet recording paper according to the present invention, the 75 ° white paper glossiness defined by JIS P-8142 on the surface of the ink receiving layer is preferably 65% or more. Such high gloss inkjet recording paper is suitable for bookbinding applications composed of a plurality of pages such as books, magazines, albums, catalogs, and materials. Bookbinding products suitable for on-demand printing can be provided at a low price, which is more practical.

  According to the present invention, it is possible to provide an ink jet recording paper having a texture similar to that of general printing coated paper and excellent in ink absorbability. Furthermore, since the present invention can provide an inexpensive inkjet recording paper with the same production efficiency as that of conventional coated paper for general printing, the paper of the present invention is used particularly in commercial printing fields such as on-demand printing. It is most suitable as an inkjet recording paper to be used.

  Next, the present invention will be described in detail with reference to embodiments, but the present invention is not construed as being limited to these descriptions. As long as the effect of the present invention is exhibited, the embodiment may be variously modified.

<Support>
The raw material pulp constituting the base paper of the ink jet recording paper according to the present invention includes LBKP (hardwood bleached kraft pulp) and NBKP (softwood bleached kraft pulp) as chemical pulp, GP (crushed wood pulp) and PGW (pressurized as mechanical pulp). Crush (pulverized wood pulp), RMP (refinery mechanical pulp), TMP (thermomechanical pulp), CTMP (chemithermomechanical pulp), CMP (chemimechanical pulp), CGP (chemiground pulp), wood pulp, DIP (deinked pulp) ) And other non-wood pulps such as kenaf, bagasse, bamboo, and cotton. These can be used alone or in combination at any ratio. In addition, a synthetic fiber can be further blended within a range that does not impair the object and effect of the present invention. It is desirable to use chlorine-free pulp such as ECF (Elemental Chlorine Free) pulp or TCF (Totally Chlorine Free) pulp with less environmental impact.

  Further, the pulp constituting the base paper according to the present invention is preferably a paper material having an appropriate beating degree as an inkjet recording paper. Suitable beating degree is, for example, Canadian standard freeness (freeness) (JIS P 8121: 1995 “Pulp Freeness Test Method”), 350 to 650 ml CSF.

  Examples of the filler used for the base paper according to the present invention include heavy calcium carbonate, light calcium carbonate, magnesium carbonate, titanium dioxide, synthetic silica, alumina, talc, calcined kaolin clay, kaolin clay, bentonite, zeolite, aluminum hydroxide. It is possible to use known fillers such as zinc oxide. The filler content in the paper is preferably 2 to 20 parts by mass with respect to 100 parts by mass of the dry mass of the pulp. More preferably, it is 4-15 mass parts. In the case of 2 parts or less, the opacity and whiteness are likely to decrease, and the effect cannot be obtained. When the amount exceeds 20 parts by mass, the strength of the paper decreases, it cannot withstand the load during printing and processing, and is difficult to use.

  In addition to the above pulp and filler, internal paper strength enhancers such as sizing agents and wet paper strength enhancers, sulfuric acid bands, yield improvers, pitch control agents, colored dyes, colored pigments, fluorescent materials Various papermaking chemicals such as dyes can be appropriately used. There are no particular limitations on the method for preparing each paper stock, the formulation, and the method for adding each papermaking chemical as long as the effects of the present invention are not impaired. In particular, the content of the internally added paper stock is preferably 0.01 to 2.0 parts by mass. More preferably, it is 0.05 to 1.5 parts by mass. Excellent bookbinding ability.

  The paper making method of the base paper according to the present invention is not particularly limited, and a known paper machine such as a circular net paper machine, a long net paper machine, a twin wire paper machine, etc. is applied using the above-mentioned stock. Paper making is possible.

  A surface sizing solution can be applied to the base paper obtained by the paper making method in order to suppress excessive penetration of the ink receiving layer coating solution into the base paper. The surface sizing liquid is not particularly limited, and examples thereof include known water-soluble polymers such as polyvinyl alcohol, polyacrylamide, and starch.

Although the basic weight of the base paper which concerns on this invention is not specifically limited, Usually, it is 30-300 g / m < ² >.

<Ink receiving layer>
The ink jet recording paper according to the present invention is preferably provided with at least one ink receiving layer on one side or both sides of the paper support obtained by the above method from the viewpoint of satisfying ink absorbability. The ink receiving layer is mainly composed of a pigment containing a hollow plastic pigment and a binder. By using the hollow plastic pigment, the amount of the release agent used for suppressing dusting in the calendar process can be reduced, and thereby the deterioration of the ink absorbability accompanying the addition of the release agent can be suppressed.

  The hollow plastic pigment is a pigment composed of fine particles of the following materials, each particle having an air layer therein. The hollow plastic pigment in the pigment is 0.05 to 30 parts by mass, preferably 0.1 to 20 parts by mass, more preferably 0.4 to 14 parts by mass, and further 0.5 to 10 parts by mass with respect to 100 parts by mass of the pigment. Part by mass. When the amount is less than 0.05 parts by mass, the opacity and the covering property are lowered, and the glossiness of the white paper may be inferior. When the amount exceeds 30 parts by mass, the effect of the present invention, that is, the effect on the glossiness of the white paper is saturated, which is not preferable from the viewpoint of manufacturing cost. In addition, blocking tends to occur and the bookbinding processability may be poor. Furthermore, the ink absorbability of the ink receiving layer is deteriorated, and as a result, printing unevenness may occur.

  The hollow plastic pigment used in the ink receiving layer has a hollow ratio of preferably 25 to 90%, more preferably 40 to 80%, and further preferably 25 to 65%. If it is less than 25%, sufficient white paper glossiness cannot be obtained, and if it exceeds 90%, it becomes undesirably white paper gloss more than desired, which is not preferable from the viewpoint of production cost. Moreover, 0.1-10 micrometers is preferable and, as for the average particle diameter of a hollow plastic pigment, More preferably, it is 0.5-5 micrometers. When the average particle size is less than 0.1 μm, when it exceeds 10 μm, the glossiness of the white paper decreases.

  The material of the hollow plastic pigment is preferably a copolymer of polystyrene and other copolymerizable monomers mainly composed of styrene, and more preferably polystyrene. Examples of other copolymerizable monomers include acrylonitrile, methyl methacrylate, butadiene, and isoprene.

  The pigments other than the hollow plastic pigment used in this embodiment include one or more known pigments used for general printing paper, such as kaolin, talc, calcium carbonate, magnesium carbonate, barium sulfate, calcium sulfate. Inorganic pigments such as titanium dioxide, zinc oxide, zinc sulfate, zinc carbonate, calcium silicate, aluminum silicate, magnesium silicate, diatomaceous earth, aluminum hydroxide and magnesium hydroxide, or organic pigments such as acrylic, styrene, vinyl chloride and nylon Can be mentioned. Solid plastic pigments can also be used. Among these, the use of at least one selected from calcium carbonate, kaolin, and talc is preferable because the same texture as that of general coated paper can be obtained. In the present invention, it is preferable not to use pigments such as alumina, silica, boehmite, etc., which increase the cost. The combination of the pigments is not particularly limited except that a hollow plastic pigment is an essential component. For example, 0.1 to 15 parts by mass of the hollow plastic pigment, 30 to 65 parts by mass of kaolin with respect to 100 parts by mass of the total pigment, Heavy calcium carbonate may be used at a ratio of 30 to 65 parts by mass. Alternatively, for example, 0.1 to 15 parts by mass of hollow plastic pigment and 85 to 99.9 parts by mass of silica may be used with respect to 100 parts by mass of the total pigment.

  As the binder used in the ink receiving layer, it is necessary to use styrene butadiene latex in order to make the coating layer strength similar to that of general printing paper. Since styrene butadiene latex is inexpensive, it is preferable from the viewpoint of production cost. Furthermore, depending on the purpose, for example, polyvinyl alcohol (including modified polyvinyl alcohol such as silanol-modified polyvinyl alcohol and carboxyl-modified polyvinyl alcohol), polyvinyl acetal, oxidized starch, etherified starch, carboxymethylcellulose, hydroxyethylcellulose, casein, gelatin, Soy protein, polyethyleneimide resin, polyvinylpyrrolidone resin, polyacrylic acid or its copolymer, maleic anhydride copolymer, acrylamide resin, acrylate resin, polyamide resin, polyurethane resin, polyester resin , Polyvinyl butyral resin, alkyd resin, epoxy resin, epichlorohydrin resin, urea resin, styrene-butadiene copolymer, methyl methacrylate For general printing paper such as acrylic polymer latex such as tadiene copolymer, acrylic ester, methacrylic ester polymer or copolymer, and vinyl polymer latex such as ethylene-vinyl acetate copolymer The known binder used can be used in combination. In particular, from the viewpoint of the coating layer strength of the ink-receiving layer and the production cost, the combined use of styrene butadiene latex and starch used for general printing coated paper is preferable.

  The blending amount of the binder to be blended in the ink receiving layer is determined in consideration of the printability of the recording medium, the strength of the ink receiving layer, and the coating liquid property. Usually, it may be added in the range of 3 to 60 parts by mass with respect to 100 parts by mass of the pigment. Preferably, it adds in the range of about 5-50 mass parts. If the amount is less than 3 parts by mass, the coating layer strength may decrease. If it exceeds 60 parts by mass, the ink absorbability may decrease. Further, the blending amount of the styrene butadiene latex blended in the ink receiving layer is preferably 3 to 30 parts by mass with respect to 100 parts by mass of the pigment. If the amount is less than 3 parts by mass, the coating layer strength may decrease, and if it exceeds 30 parts by mass, the ink absorbability may decrease. Furthermore, the compounding quantity of the starch mix | blended with an ink receiving layer is 0-10 mass parts, Preferably it is 1-5 mass parts.

  Further, in the present invention, in order to obtain a texture similar to that of coated paper for general printing, an ink receiving layer is provided on the base paper, and then calendar processing is performed by a known calendar device such as a super calendar, a machine calendar, or a soft calendar. It is necessary to give gloss.

  However, the roll surface of the calendar processing device is relatively easily soiled, and depending on the calendar processing conditions such as the heating temperature of the roll in the calendar device, roll soiling (dusting) due to the ink receiving layer is likely to occur. When roll contamination occurs, it becomes difficult to impart gloss, and a texture similar to that of general printing coated paper cannot be obtained. Further, since defects also occur on the surface of the ink receiving layer, the ink water absorption is lowered and an excellent printed image cannot be obtained.

  Roll contamination of the calender device can be prevented by including a release agent in the ink receiving layer. Known types of release agents include polyethylene emulsion, liquid paraffin, paraffin wax and the like.

  However, since the release agent described above has high water repellency, it is inferior in ink absorbability. Therefore, in the present invention, by adding 0.05 to 5.0 parts by mass of the content of one or more higher fatty acid salts or derivatives thereof to 100 parts by mass of the pigment in the ink receiving layer, It is possible to achieve both roll stain prevention and ink absorbability. More preferably, it is 0.1-3.0 mass parts. More preferably, it is 0.15-2.0 mass part. Depending on the required paper properties, for example, 0.3-0.55 parts by mass, 0.65-2.0 parts by mass, 0.65-0.95 parts by mass, 1.0-2.0. It can be a mass part or the like. If it is less than 0.05 parts by mass, dusting may occur on the roll of the calender device, and if it exceeds 5.0 parts by mass, the glossiness of the blank paper may be reduced. Further, the ink absorbability of the ink receiving layer is deteriorated, and as a result, printing unevenness may occur.

  Examples of the higher fatty acid salt include calcium stearate, ammonium stearate, potassium oleate, sodium oleate, sodium laurate, potassium laurate, sodium palmitate, potassium palmitate, sodium myristate, potassium myristate and the like. It is done. Moreover, castor oil sulfated oil sodium salt is mentioned as a derivative | guide_body of a higher fatty acid salt.

<Coating method>
As a method for coating the ink receiving layer, a known coating machine such as an air knife coater, roll coater, bar coater, comma coater, blade coater, curtain coater, gravure coater, short dwell coater, gate roll coater or the like is used. . The coating amount is not particularly limited, but is preferably 3 to 40 g / m ² per one side of the base paper in terms of solid content. More preferably 5 to 30 g / ^{m 2.} If it is less than 3 g / m ² , the ink absorbability may be inferior, and if it exceeds 40 g / m ² , the cost increases, which is uneconomical. It is also possible to apply the coating liquid for forming the ink receiving layer twice or more to form the ink receiving layer with two or more layers.

  The drying method after coating is not particularly limited in the present invention, and examples include hot air drying, infrared drying, and drum drying.

  The ink receiving layer may be provided not only on one side of the base paper but also on both sides. It can be a duplex printing paper. One or more undercoat layers may be provided under the ink receiving layer.

  Next, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples. In the examples, “parts” and “%” represent “parts by mass” and “mass%”, respectively, unless otherwise specified.

Example 1
<Preparation of base paper>
Canadian Standard Freeness 410mlcsf hardwood bleached kraft pulp 100 parts, light calcium carbonate (TP-121, Okutama Kogyo Co., Ltd.) 15 parts, cationized starch 0.3 parts, neutral rosin sizing agent (CC167, Seiko PMC) (Made) It added so that it might become 0.5 parts, and it was set as the paper stock. Using this stock, a base paper having a basis weight of 90 g / m ² was produced with a long mesh multi-cylinder paper machine. The produced base paper was coated with an oxidized starch aqueous solution by a gate roll coater so that the dry coating amount was 3.0 g / m ² on both sides.

<Preparation of coating solution for ink receiving layer>
Hollow plastic pigment (MH8101, Nippon Zeon Co., Ltd.) 9 parts, kaolin (Ultra White 90, Engelhard Co., Ltd.) 51 parts, heavy calcium carbonate (Carbillax, Imeris Co., Ltd.) ) 0.1 part of a dispersant (Aron T-50, manufactured by Toa Gosei Co., Ltd.) was added to 40 parts, and after adding water, it was dispersed in water with a Coreless disperser to obtain a pigment slurry. To this pigment slurry, 3 parts of phosphate esterified starch (MS4600, manufactured by Nippon Shokuhin Kako Co., Ltd.), 13 parts of styrene bradiene latex (JSR0695, manufactured by JSR), fluorescent whitening agent (Kecoal BULC, manufactured by Nippon Soda Co., Ltd.) ) 0.2 part, 0.5 part of an aqueous dispersion of calcium stearate (LB-131, manufactured by Toho Chemical Industry Co., Ltd.) as a higher fatty acid salt is added and hydrated, and a coating liquid for an ink receiving layer having a solid concentration of 45%. Was prepared.

<Preparation of inkjet recording paper>
The ink receiving layer coating solution obtained above was applied to both sides of the base paper with a blade coater so that the dry coating amount per side was 10 g / m ^2, and after calendering, a calendering treatment was performed, and the basis weight was 110 g. An inkjet recording paper of / m ² was produced.

(Example 2)
Inkjet recording was performed in the same manner as in Example 1 except that the pigment content was changed to 0.1 part of hollow plastic pigment, 50.9 parts of kaolin, and 49 parts of heavy calcium carbonate. Recording paper was prepared.

Example 3
An ink jet recording sheet was prepared in the same manner as in Example 1 except that the amount of the pigment was changed to 1 part of hollow plastic pigment, 50 parts of kaolin, and 49 parts of heavy calcium carbonate in the preparation of the ink receiving layer coating solution. did.

Example 4
An ink jet recording paper was prepared in the same manner as in Example 1 except that the amount of the pigment was changed to 5 parts of hollow plastic pigment, 48 parts of kaolin and 47 parts of heavy calcium carbonate in preparing the ink receiving layer coating solution. did.

(Example 5)
An ink jet recording paper was prepared in the same manner as in Example 1 except that the amount of pigment was changed to 15 parts of hollow plastic pigment, 42 parts of kaolin and 43 parts of heavy calcium carbonate in the preparation of the ink receiving layer coating solution. did.

(Example 6)
An ink jet recording paper was prepared in the same manner as in Example 1 except that the amount of pigment was changed to 24 parts of hollow plastic pigment, 38 parts of kaolin, and 38 parts of heavy calcium carbonate in the preparation of the ink receiving layer coating solution. did.

(Example 7)
In the preparation of the ink receiving layer coating solution, the higher fatty acid salt was replaced with 0.05 part of an aqueous dispersion of calcium stearate (LB-131, manufactured by Toho Chemical Co., Ltd.) to 0.05 part. In the same manner as in Example 1, an ink jet recording paper was prepared.

(Example 8)
In the preparation of the ink receiving layer coating liquid, the higher fatty acid salt was changed to an aqueous dispersion of calcium stearate (LB-131, manufactured by Toho Chemical Industry Co., Ltd.) 0.5 part to 0.1 part. In the same manner as in Example 1, an ink jet recording paper was prepared.

Example 9
In the preparation of the ink-receiving layer coating liquid, the higher fatty acid salt was replaced with 2.0 parts of 0.5 parts of an aqueous dispersion of calcium stearate (LB-131, manufactured by Toho Chemical Industry Co., Ltd.). In the same manner as in Example 1, an ink jet recording paper was prepared.

(Example 10)
In the preparation of the ink-receiving layer coating solution, the examples of the fatty acid salts were the same except that 0.5 parts of the aqueous dispersion of calcium stearate (LB-131, manufactured by Toho Chemical Industry Co., Ltd.) was changed to 3.0 parts. In the same manner as in Example 1, an ink jet recording paper was prepared.

(Example 11)
In the preparation of the ink receiving layer coating solution, a higher fatty acid salt was added from 0.5 part of a calcium stearate aqueous dispersion (LB-131, manufactured by Toho Chemical Co., Ltd.) to potassium oleate (OS soap, manufactured by Kao Corporation). An ink jet recording paper was produced in the same manner as in Example 1 except that the amount was changed to 0.5 part.

(Example 12)
In the preparation of the ink receiving layer coating solution, a higher fatty acid salt was added from 0.5 part of an aqueous dispersion of calcium stearate (LB-131, manufactured by Toho Chemical Co., Ltd.) to sodium myristate (produced by Showa Chemical Co., Ltd.). An ink jet recording paper was produced in the same manner as in Example 1 except that the number was changed to 5 parts.

(Example 13)
In the preparation of the ink receiving layer coating solution, the higher fatty acid salt was mixed with 0.5 parts of calcium stearate aqueous dispersion (LB-131, manufactured by Toho Chemical Industry Co., Ltd.), ammonium stearate aqueous dispersion (Nopco DC- An ink jet recording paper was prepared in the same manner as in Example 1 except that it was changed to 100A (manufactured by San Nopco).

(Example 14)
Inkjet recording was carried out in the same manner as in Example 1 except that the amount of pigment was 9 parts of hollow plastic pigment and 91 parts of synthetic silica (thyroid 74x5500, manufactured by GRACE Davison) in the preparation of the ink receiving layer coating solution. A paper was prepared.

(Comparative Example 1)
In the preparation of the ink receiving layer coating solution, the ink jet recording paper was prepared in the same manner as in Example 1 except that the pigment content was 50 parts kaolin and 50 parts heavy calcium carbonate and no hollow plastic pigment was added. Produced.

(Comparative Example 2)
An ink jet recording paper was prepared in the same manner as in Example 1 except that calcium stearate was not added in the preparation of the ink receiving layer coating solution.

(Comparative Example 3)
Example 1 except that calcium stearate was not added, the amount of pigment was 50 parts kaolin and 50 parts heavy calcium carbonate, and no hollow plastic pigment was added in the preparation of the ink receiving layer coating solution. Inkjet recording paper was prepared in the same manner as described above.

  The following tests were carried out on the ink jet recording paper obtained in each example and comparative example. The results are shown in Tables 1 and 2.

(1) Dusting evaluation Dusting evaluation was visually evaluated as follows.
(Double-circle): There is no dirt on the roll surface of a calendar processing apparatus, and it is practical.
○: Slight dirt is generated on the roll surface of the calendar processing apparatus, but it is practical.
Δ: Dirt is generated on the roll surface of the calendar processing apparatus, which is not practical.
X: The surface of the roll of the calendar processing apparatus is significantly stained and cannot be used practically.

(2) Gloss of white paper According to JIS-P8142: 2005 “Paper and paperboard—Measurement method of 75 degree specular gloss”, the glossiness meter (Gloss meter GM26D, manufactured by Murakami Color Research Laboratory) was used to measure the surface of the ink receiving layer. Glossiness (75 ° ISO glossiness) was measured. The higher the numerical value, the better the glossiness and the better. Preferably it is 65% or more.

(3) Unevenness of solid printing part Solid printing was performed using the following inkjet printer, and the degree of unevenness of the printing part was visually evaluated as follows.
Printer A: CM8060 Color MFP (manufactured by Hewlett-Packard Company)
Printer B: PX-G5300 (manufactured by Seiko Epson Corporation)
(Double-circle): There is no printing nonuniformity and it can be used practically.
○: Print unevenness slightly occurs but can be used practically.
Δ: Printing unevenness occurs and is not practical.
X: Printing unevenness occurs remarkably and is not practical.

(4) Processing suitability of bookbinding Solid printing was performed using the following ink jet printer, and pressurization was performed while the printed surfaces were folded in two, and processing suitability was evaluated based on the presence or absence of blocking.
Printer: CM8060 Color MFP (manufactured by Hewlett-Packard Company)
A: Blocking does not occur at all and can be used practically.
○: Slight blocking occurs but can be used practically.
Δ: Blocking occurs, impractical.
X: Blocking occurs remarkably and is not practical.

  As is clear from Tables 1 and 2, the inkjet recording papers obtained in Examples 1 to 14 have a texture of a general printing coated paper and are excellent in printing with an inkjet printer.

  The ink jet recording paper obtained in Example 5 and Example 6 has a relatively large content of hollow plastic pigment in the ink receiving layer. It was within the range. Further, the ink jet recording paper obtained in Example 6 was inferior in ink absorbability, and as a result, slight printing unevenness occurred, but it was within the practical range. In addition, the ink jet recording paper obtained in Example 10 had a relatively high content of higher fatty acid salt in the ink receiving layer, so that the ink absorbability was inferior and printing unevenness slightly occurred. It was within the practical range.

  The ink jet recording paper obtained in Comparative Example 1 was inferior in white paper gloss because the ink receiving layer did not contain a hollow plastic pigment. The ink jet recording paper obtained in Comparative Example 2 did not contain a higher fatty acid salt in the ink receiving layer, and therefore, the roll smear of the calendar device occurred. The ink jet recording paper obtained in Comparative Example 3 contained no hollow plastic pigment and higher fatty acid salt in the ink receiving layer, so that the calendar device was rolled and the paper gloss was inferior.

Claims (4)

  An ink-receiving recording layer obtained by calendering an ink-receiving layer mainly comprising a pigment containing a hollow plastic pigment and a styrene-butadiene latex on at least one side of a base paper, wherein a higher fatty acid salt is formed on the ink-receiving layer. An ink jet recording paper comprising:   2. The inkjet recording paper according to claim 1, wherein the content of the higher fatty acid salt in the ink receiving layer is 0.05 to 5 parts by mass with respect to 100 parts by mass of the pigment.   The inkjet recording paper according to claim 1 or 2, wherein the 75 ° white paper glossiness defined by JIS P-8142 on the surface of the ink receiving layer is 65% or more.   A method for using an inkjet recording paper, wherein the inkjet recording paper according to any one of claims 1 to 3 is printed by an on-demand printing method and used for bookbinding.