JP6795902B2 - Glossy paper for inkjet and its manufacturing method - Google Patents

Description

The present disclosure relates to glossy paper for an inkjet which is excellent in transportability of a reverse paper feed type printer.

The inkjet recording method is a method in which dots are formed by ejecting ink droplets and adhering them on a recording paper to perform recording. In recent years, technological advances in inkjet printers, inks, and recording media have made it possible to record with high print quality. As the medium dedicated to these inkjet recordings, a medium in which a paper and / or a film is used as a support and a pigment coating layer containing a pigment and a binder as main components is provided on the surface is often used.

The dedicated inkjet medium is further classified into a matte medium and a glossy medium according to the surface state. The latter glossy medium is used when image quality closer to silver halide photography is required.

As a general method for producing a glossy medium, there are a method of forming an ink receiving layer by a casting method to give gloss to the surface and a method of forming an ink receiving layer on a base material for photographic paper.

The latter base material for photographic paper is generally called RC paper (resin coated paper), and since a polyethylene film layer is formed on the base material of paper, when an ink receiving layer is formed on the surface thereof. Since the film layer is smooth, the surface of the ink receiving layer is also smooth, and a glossy surface is likely to be formed.

However, the overall cost is higher than that of the former glossy medium by the casting method because it is necessary to increase the coating amount in order to improve the ink absorbency and the base material itself is more expensive than paper. .. In addition, when it is discarded, there is a problem that it cannot be recycled because it is a composite material.

On the other hand, in recent years, personal inkjet printers place importance on design, and the number of reverse paper feed printers with a compact housing is increasing. In this type of printer, for example, when printing on the ink receiving layer, the opposite side of the ink receiving layer is set facing up, and when the paper is fed, the paper is inverted and printed on the ink receiving layer. Unlike conventional rear paper feed printers, the paper feed mechanism is complicated, and poor transport of double feed, etc. (here, double feed is a phenomenon in which multiple sheets are stacked and fed). There is a problem that is likely to occur. In particular, in the case of glossy paper for inkjet, the coefficient of friction between the glossy surface and the opposite surface tends to be large, so that transfer defects are likely to occur. Further, the higher the mapability, the easier it is for the paper to come into close contact with each other, and the more likely it is that transport defects such as double feeding will occur. Further, in the case of postcards, since they are lightweight, double feeding tends to occur more easily. Conventionally, various proposals have been made for the purpose of improving transportability. For example, there is a proposal to improve the transportability by defining the pigment and the binder of the ink receiving layer (see, for example, Patent Document 1).

JP 2015-174440

However, in the case of the technique described in Patent Document 1, there is a problem that if the imageability of the glossy surface is high, transfer defects are likely to occur.

As described above, it is more difficult to complete the transportability of the reverse paper feed type printer, which has become widespread in recent years, so as to eliminate transport defects when the medium used is inkjet glossy paper.

Therefore, an object of the present disclosure is to provide a high-quality glossy paper having high reproducibility and a glossy paper for an inkjet having good transportability. More specifically, even though it is high-quality glossy paper, when multiple sheets of paper are set in the printer, an appropriate gap is created between the papers, and the paper is easily separated during paper feeding, resulting in double feeding. It is to provide glossy paper for inkjet which is hard to occur.

The glossy ink jet paper according to the present invention is a glossy ink jet paper in which an ink receiving layer containing a pigment and a binder is provided on one side of a paper base material, and the ink receiving layer has an average secondary particle diameter as the pigment. Is a porous fine pigment of 20 to 1000 nm, and the opposite surface of the one side provided with the ink receiving layer is the surface of the paper base material or the size press processed surface, and the opposite surface is the calendar processed surface. , and the image clarity of the ink-receiving layer, JIS H 8686-2: 1999 in conditions of optical comb width of 2mm incident reflection angle 60 ° by the "image clarity test method for aluminum and anodized coatings on aluminum alloys", 55% It is characterized by the above, and the Beck smoothness of the opposite surface is 5 seconds or more and 20 seconds or less.

By the geometry of the multi-porous fine pigment, when forming an ink-receiving layer intralayer easily voids are formed, the excellent ink absorption of the dye ink and pigment ink.

In the glossy paper for inkjet according to the present invention, the porous fine pigment is one selected from vapor phase silica, precipitated silica, γ-alumina, θ-alumina, boehmite (including pseudo boehmite), and alumina-modified silica. As described above, it is preferable that the BET specific surface area of the porous fine pigment is 100 to 400 m ² / g. It is possible to improve the ink absorbency of the dye ink and the pigment ink.

The ink-jet glossy paper according to the present invention, the porous fine pigment preferably has an average primary particle diameter of 5 to 30 nm. The balance between the ink absorbency of the pigment ink and the glossiness of the ink receiving layer is improved.

In the glossy paper for inkjet according to the present invention, it is preferable that monodisperse spherical colloidal silica is distributed on the outermost surface of the ink receiving layer. The effects of improving the mapability of the surface of the ink receiving layer, improving the scratch resistance, and lowering the friction coefficient can be seen.

Inkjet glossy paper according to the present invention, before Kihan face is address plane is preferably postcard paper. Since postcards are lightweight, double feeding is likely to occur, but according to the present invention, postcards are excellent in transportability.

The method for producing glossy ink paper according to the present invention is the method for producing glossy ink paper in which an ink receiving layer containing a pigment and a binder is provided on one side of a paper base material, wherein the ink receiving layer is provided. opposite side of the composed face is a surface or size press treated surface of the paper substrate, a step of preparing a paper substrate having an adjusted Bekk smoothness of the opposite surface below 40 seconds 10 seconds by calender, the The ink receiving layer of the paper substrate is provided with a coating liquid for an ink receiving layer containing the pigment and the binder and containing the porous fine pigment having an average secondary particle diameter of 20 to 1000 nm as the pigment. The coating layer contains a coagulating liquid containing 5% by mass or more of a coagulant for coagulating the binder in a step of coating a surface to be formed to form a coating layer. It has a step of applying and solidifying the ink while it is in a wet state and then pressing it against a cast drum, and the imageability of the ink receiving layer after the step is JIS H 8686-2: 1999 ". Beck smoothness on the opposite surface of the surface on which the ink receiving layer is provided, which is 55% or more under the condition of an optical comb width of 2 mm and an input reflection angle of 60 ° according to the "imageability test method of anodized film of aluminum and aluminum alloy". Is 5 seconds or more and 20 seconds or less.

According to the present disclosure, it is possible to provide a glossy paper for inkjet which is a glossy paper having high image quality and good transportability. For example, even if a reverse paper feed type personal inkjet printer, which has become widespread in recent years, is used, transport defects such as double feeding do not occur, so that the significance of the present invention is considered to be great. Further, in the present disclosure, since paper is used as the base material, the manufacturing cost is lower than that of the photographic paper base material having a film layer, the material can be recycled when discarded, and it is preferable from the viewpoint of effective use of resources. ..

Hereinafter, the present invention will be described in detail by showing embodiments, but the present invention is not construed as being limited to these descriptions. The embodiments may be modified in various ways as long as the effects of the present invention are exhibited.

Commonly used pigments contained in the coating liquid for forming the ink receiving layer of glossy inkjet paper include precipitation silica, spherical colloidal silica, non-spherical colloidal silica in which a plurality of spherical colloidal silicas are linked, and vapor phase. Examples thereof include silica, alumina (including boehmite and pseudo boehmite crystals), and alumina-modified silica.

In addition, for porous fine pigments such as vapor-phase method silica and alumina, and non-spherical colloidal silica in which a plurality of spherical colloidal silicas are linked, glossy paper for ink jet is used because of its extremely high specific surface area and good ink absorption. Although it is a commonly used pigment, its geometric shape makes it easy to form voids during film formation, and while it has excellent ink absorbency for dye inks and pigment inks, it has a high friction coefficient and poor transport. It is easy to occur.

The porous fine pigment used in the present embodiment is a pigment in which primary particles aggregate to form secondary or higher particles, and the particles themselves have voids. It is preferable that the average primary particle diameter is 5 to 30 nm, and the average secondary particle diameter (when a tertiary or higher particle is formed, the average particle diameter of the final aggregated shape is used) is 20 to 1000 nm. Here, it is preferable that the average primary particle diameter is 5 to 30 nm or the average secondary particle diameter is 20 to 1000 nm, or both. As a case where either one is satisfied, for example, when the primary particles cannot be visually recognized even by observing the microstructure of the porous fine pigment, the secondary particles are observed. More preferably, the average primary particle diameter is 5 to 25 nm and the average secondary particle diameter is 20 to 500 nm. The porous fine pigment used in the present embodiment has such a particle size, and is vapor phase silica, precipitation silica, gel silica, non-spherical colloidal silica in which a plurality of spherical colloidal silicas are linked, and boehmite. (Including pseudo-bemite), γ-alumina, θ-alumina, σ-alumina, and alumina-modified silica are preferable. From the viewpoint of ink absorbency and glossiness of the pigment ink, it is preferable to use vapor phase silica, precipitated silica, γ-alumina, θ-alumina, boehmite (including pseudo boehmite), and alumina-modified silica. Further, it is preferable to contain vapor phase silica from the viewpoint of good balance between image quality and ink absorption.

The BET specific surface area of the porous fine pigment used in the present embodiment is preferably 100 to 400 m ² / g. More preferably, it is 150 to 380 m ² / g, and particularly preferably 180 to 350 m ² / g. If the BET specific surface area is less than 100 m ² / g, the image sharpness of the pigment ink may be inferior. If the BET specific surface area exceeds 400 m ² / g, the viscosity of the coating liquid may be too high and the stability may be inferior. Here, the BET specific surface area is the surface area per unit mass determined by the BET method. The BET method is one of the methods for measuring the specific surface area of powder by the vapor phase adsorption method, and is a method for obtaining the total surface area of 1 g of a sample from the adsorption isotherm, that is, the specific surface area. Usually, nitrogen gas is often used as the adsorbed gas, and the method of measuring the adsorbed amount from the pressure or volume change of the adsorbed gas is most often used. The most prominent ones for expressing the isotherms of multimolecular adsorption are the Brunauer, Emmett, and Teller equations, which are called BET equations and are widely used for surface area determination. The amount of adsorption is determined based on the BET formula, and the surface area is obtained by multiplying the area occupied by one adsorbed molecule on the surface. Further, as long as the effect of the present invention is not impaired, it may be used in combination with a porous fine pigment having a BET specific surface area of less than 100 m ² / g.

The particle size of the porous fine pigment used in this embodiment can be determined mainly by a dynamic light scattering method (for example, DLS-6500 manufactured by Otsuka Electronics Co., Ltd.), and a field capable of high-magnification observation. It is also possible to obtain it by directly observing it with an emission type electron microscope. A field emission electron microscope is used to determine the average primary particle size, and a dynamic light scattering method is used to determine the average secondary particle size. In the present disclosure, the average secondary particle diameter means the number average particle diameter of the secondary particles.

Further, as the binder contained in the ink receiving layer, polyvinyl alcohol (including modified polyvinyl alcohol such as silanol-modified polyvinyl alcohol and carboxyl-modified polyvinyl alcohol), polyvinyl acetal, oxidized starch, etherified starch, carboxymethyl cellulose, and hydroxy Ethyl cellulose, casein, gelatin, soybean protein, polyethyleneimide resin, polyvinylpyrrolidone resin, polyacrylic acid or its copolymer, maleic anhydride copolymer, acrylamide resin, acrylic acid ester resin, polyamide resin, acrylic Based resin, styrene-acrylic resin, polyurethane resin (including cationic polyurethane resin), polyester resin, polyvinyl butyral resin, alkyd resin, epoxy resin, epichlorohydrin resin, urea resin, melamine resin, styrene- Acrylic polymers such as butadiene copolymers, methyl methacrylate-butadiene copolymers, acrylic acid esters, methacrylic acid ester polymers or copolymers Latexes, vinyl polymers such as ethylene-vinyl acetate copolymers Examples thereof include latexes, a composite resin of colloidal silica and acrylic resin, and a composite resin of colloidal silica and styrene-acrylic resin, which are used alone or in combination. The amount of the binder used is determined in consideration of the printability of the recording medium, the strength of the coating layer, the surface glossiness, the paint property, and the like. Usually, it is preferable to add the pigment in the range of 1 to 100 parts by mass with respect to 100 parts by mass of the pigment. More preferably, it is added in the range of 5 to 60 parts by mass, and further preferably 10 to 50 parts by mass. If it is less than 1 part by mass, the strength of the coating layer may decrease. If it exceeds 100 parts by mass, the ink absorbability may decrease.

From the viewpoint of color development, the coating liquid of the ink receiving layer preferably contains polyvinyl alcohol as a binder.

It is preferable to add a cationic polymer to the ink receiving layer in addition to the pigment and the binder. The action of the cationic polymer is that it reacts with the anionic component in the dye used in the ink to form a salt that is insoluble in water, so that the ink is more firmly fixed to the ink receiving layer and is water resistant. Improves sex. Examples of such cationic polymers include polyethyleneimine, epichlorohydrin-modified polyalkylamine, polyamine, polyamine polyamide epichlorohydrin, dimethylamine ammonia epichlorohydrin, polyvinylbenzyltrimethylammonium halide, polydiacrylicdimethylammonium halide, polydimethylaminoethyl methacrylate hydrochloride, and polyvinyl. Pyridium halide, cationic polyacrylamide, cationic polystyrene copolymer, diallyldimethylammonium chloride polymer, diallyldimethylammonium chloride sulfur dioxide copolymer, diallyldimethylammonium chlorideamide copolymer, dicyandiamideformalin polycondensate, dicyandiamidediethylenetriamine Polycondensate, polyallylamine, polyallylamine hydrochloride, polyacrylamide resin, polyamide epoxy resin, melamine resin acid colloid, urea resin, cationically modified polyvinyl alcohol, amino acid type amphoteric surfactant, betaine type compound, polyamidine type compound, In addition, quaternary ammonium salts and the like are used. The amount to be added is not particularly limited, but it is preferable to add the pigment in the range of 1 to 50 parts by mass with respect to 100 parts by mass of the pigment. More preferably, it is added in the range of 5 to 40 parts by mass. If it is less than 1 part by mass, the water resistance of the printing part may decrease. If it exceeds 50 parts by mass, the ink absorbability may be inferior.

Furthermore, additives such as dispersants, thickeners, preservatives, defoamers, coloring dyes, coloring pigments, fluorescent whitening agents, water resistant agents, antioxidants, and ultraviolet absorbers are added to the ink receiving layer. It can be appropriately selected and added.

As a coating method of the coating liquid for forming the ink receiving layer of the present embodiment, known coating methods such as an air knife coater, a roll coater, a reverse roll coater, a bar coater, a comma coater, a blade coater, and a simultaneous multi-layer coating machine are used. There is a machine, but any one may be used. The amount of coating is preferably in the range of 3 to 30 g / m ^{2 in} terms of solid content, and more preferably in the range of 5 to 25 g / m ² . If the coating amount exceeds 30 g / m ² , the productivity is inferior, and if the coating amount is less than 3 g / m ² , it is difficult to form a sufficient glossy surface.

The glossy paper for inkjet according to the present invention is preferably produced by a known cast coating method. Wet method, coagulation method, and rewet method are known as cast coat methods, and any method can be used, but in the present embodiment, the coagulation method is preferable from the viewpoint of image quality. The coagulation method is a method in which a coagulation liquid is applied while the coating layer is in a wet state, coagulation treatment is performed, and then pressure contact is applied to the cast drum. In the coagulation treatment, it is important to select a coagulant that effectively coagulates with the binder component of the coating layer, and in this embodiment, for example, a boron compound can be used. Further, when the coagulation liquid concentration is high, the coagulation force becomes strong and the scratch resistance is further improved, which is preferable. The content of the coagulant is preferably 5% by mass or more with respect to the coagulant that can coagulate. If it is less than 5% by mass, the surface strength may decrease, and more preferably 10% by mass or more. The upper limit of the content of the coagulant is preferably 200% by mass or less with respect to the binder that can coagulate. It is also possible to add colloidal silica to the coagulation liquid. In that case, colloidal silica is present (distributed) on the outermost surface of the ink receiving layer, and has effects such as improvement of image quality of the glossy surface, improvement of scratch resistance of the glossy surface, and reduction of the friction coefficient of the glossy surface. The colloidal silica is preferably monodisperse spherical colloidal silica from the viewpoint of the effect.

In addition, the time from coating the ink receiving layer to applying the coagulating liquid, the time from applying the coagulating liquid to reaching the cast drum, the cast drum temperature, the pressure at the time of crimping, and the line speed are adjusted. By doing so, a surface having a high glossiness can be formed. It is necessary to optimize these conditions by finding the optimum conditions according to the equipment and paint used.

In addition, after casting, you may perform calendar processing such as machine calendar, soft calendar, super calendar, etc., and for curl adjustment, apply water, curl adjuster, etc. on the back side or humidify to adjust curl. Can also be done.

Further, the image quality of the ink receiving layer under the condition of the optical comb width of 2 mm and the reflection angle of 60 ° according to JIS H 8686-2: 1999 “Method for testing the image quality of anodized film of aluminum and aluminum alloy” is 55% or more. Is necessary from the viewpoint of glossiness. More preferably, the reproducibility is 60% or more. If the image mapping property is 60% or more, it can be said that the product has a more excellent glossiness. Here, the reason why the input / reflection angle is changed from 45 ° described in JIS to 60 ° is to make it easier to evaluate the difference in glossiness.

In the glossy paper for inkjet of the present embodiment, it is preferable to provide one or more underlayers under the ink receiving layer from the viewpoint of economy and ink absorption. The under layer contains a white pigment and a binder as main components. The white pigment preferably contains synthetic silica. Further, the binder contained in the under layer is preferably polyvinyl alcohol or ethylene-vinyl acetate.

As the air-permeable paper base material used in the present embodiment, a paper base material such as high-quality paper, medium-quality paper, or white paperboard can be used. Further, in the present embodiment, it is desirable to use ECF (Elemental Chlorine Free) pulp or TCF (Totally Chlorine Free) pulp having a low chlorine content as the raw material pulp in consideration of the case where it is recycled as fuel. Also known as fillers to be used include heavy calcium carbonate, light calcium carbonate, magnesium carbonate, titanium oxide, synthetic silica, alumina, talc, calcined kaolin clay, kaolin clay, bentonite, zeolite, aluminum hydroxide, zinc oxide and the like. It is possible to use the pigments of.

In addition to the above pulp and filler, various paper-making chemicals such as known paper strength agents, sulfuric acid bands, yield improvers, sizing agents, dyes, and fluorescent dyes are appropriately used in the paper materials. The method of preparing each paper material, the method of blending, and the method of adding each paper-making chemical are not particularly limited as long as they do not impair the effects of the present embodiment. Further, it is possible to make a paper by applying a known paper machine such as a circular net paper machine, a long net paper machine and a twin wire paper machine using the above paper material. It is also possible to use a multilayer paper having two or more layers as a base material.

Further, in order to suppress excessive penetration of the ink receiving layer coating liquid, it is preferable to apply a known water-soluble polymer such as starch, polyvinyl alcohol, or polyacrylamide to the paper substrate by a size press or the like.

In the inkjet glossy paper of the present invention, the Beck smoothness on the opposite surface of the ink receiving layer is set to 20 seconds or less. It is preferably 19 seconds or less, and more preferably 18 seconds or less. If the Beck smoothness on the opposite surface of the ink receiving layer exceeds 20 seconds, there is a problem of double feeding. The lower limit is not particularly limited, but is preferably 5 seconds or longer, and more preferably 10 seconds or longer. If the Beck smoothness is less than 5 seconds, the surface of the ink receiving layer becomes uneven, and the reproducibility tends to deteriorate. As a method of adjusting the Beck smoothness on the opposite surface of the ink receiving layer to 20 seconds or less, for example, the smoothness is appropriately adjusted by a wet press or a calendar at the time of paper substrate papermaking. After the cast coating treatment, the smoothness of the opposite surface of the ink receiving layer tends to decrease, so it is preferable to adjust the Beck smoothness to be higher than the aim of the final product. As the paper substrate before the ink receiving layer is provided, the Beck smoothness is preferably 40 seconds or less. More preferably, it is 35 to 10 seconds. If it is less than 10 seconds, the glossy surface may become uneven and the image quality of the glossy surface may deteriorate. If the Beck smoothness of the paper substrate exceeds 40 seconds, there is a problem of double feeding.

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. Further, "parts" and "%" shown in the examples indicate solid mass parts and solid mass% unless otherwise specified.

(Example 1)
(Formation of under layer)
The paper base material was high-quality paper having a basis weight of 170 g / m ² , which was surface-treated with oxidized starch by a size press, and the Beck smoothness on the opposite surface of the surface to which the ink receiving layer was applied was adjusted to 35 seconds. Next, 100 parts by mass of synthetic silica (Mizukasil P-78A, manufactured by Mizusawa Industrial Chemicals, Inc.) as a pigment, 12 parts by mass of polyvinyl alcohol (PVA117: manufactured by Kuraray Co., Ltd.) as a binder, and ethylene-vinyl acetate (Polysol EVA AD-10). : 43 parts by mass of Showa Polymer Co., Ltd.) and 25 parts by mass of a cationic polymer (Papiogen P-105: manufactured by Senka Co., Ltd.) were used to obtain a coating liquid for an underlayer having a solid content concentration of 20% by mass. Subsequently, this coating liquid for the under layer was applied and dried on one side of the paper substrate with an air knife coater so that the absolute dry coating amount was 10 g / m ^2, and the under layer was applied.
(Formation of ink receiving layer)
Next, as a pigment for the ink receiving layer coating liquid, 100 parts by mass of vapor phase silica (HDK T30, BET specific surface area 300 m ² / g, average primary particle diameter 10 nm, average secondary particle diameter 150 nm: manufactured by Wacker), binding. As an agent, 3 parts by mass of polyvinyl alcohol (PVA-R2105: manufactured by Kuraray), 10 parts by mass of polyvinyl alcohol (PVA-235, saponification degree 87 mol%, polymerization degree 3500: manufactured by Kuraray) and a cationic polyurethane resin (Hydran CP) -7020: 5 parts by mass of Dainippon Ink Industry Co., Ltd., and 10 parts by mass of cationic polymer (HIMAX SC-600L: manufactured by Hymo Co., Ltd.) to improve ink fixation, and stir with a serie mixer. Then, a coating liquid for an ink receiving layer having a solid content concentration of 18% was obtained. The coating liquid for the ink receiving layer was coated on the underlayer forming surface with an air knife coater so as to have an absolute dry coating amount of 10 g / m ² . Next, while the ink receiving layer was in a wet state, 1.0% boric acid and 1.0% sodium borate were used as coagulants, and monodisperse spherical colloidal silica (Snowtex YL, average particle size 80 nm: Nissan). An aqueous solution containing 2.0% (manufactured by Kagaku Kogyo Co., Ltd.) and 0.5% acrylic resin (Viniblanc 2580, manufactured by Nisshin Kagaku Kogyo Co., Ltd.) is used as a coagulating liquid (coagulating liquid concentration is 4.5%) and a wet coating amount of 30 g. After further coating to a ratio of / m ² and coagulation treatment, while the surface of the obtained coating layer was in a wet state, it was pressure-bonded to a cast drum having a surface temperature of 105 ° C. to prepare a glossy paper for inkjet. .. The coagulant is boric acid and sodium borate, the coagulant is the polyvinyl alcohol, and the content of the coagulant is 60% by mass with respect to the coagulant.

(Example 2)
A glossy paper for inkjet was produced under the conditions described in Example 1 except that the Beck smoothness of the paper base material was adjusted to 33 seconds in Example 1.

(Example 3)
A glossy paper for inkjet was produced under the conditions described in Example 1 except that the Beck smoothness of the paper base material was adjusted to 21 seconds in Example 1.

(Example 4)
In Example 1, as a pigment of the ink receiving layer coating liquid, γ-alumina (TM-300D, BET specific surface area 200 m ² / g, average primary particle diameter 10 nm, average secondary particle diameter 250 nm: manufactured by Daimei Chemical Industry Co., Ltd.) 70 parts by mass, θ-alumina (TM-100, BET specific surface area 120 m ² / g, average primary particle diameter 14 nm, average secondary particle diameter 400 nm: manufactured by Daimei Chemical Industry Co., Ltd.) 20 parts by mass, sedimentation silica (Fine Seal X) -37B, BET specific surface area 287 m ² / g, average primary particle size unknown, average secondary particle size 3.7 μm: manufactured by Tokuyama Co., Ltd.) Inkjet under the conditions described in Example 1 except for 10 parts by mass. A glossy paper for use was produced.

(Example 5)
In Example 1, as a pigment of the ink receiving layer coating liquid, 100 parts by mass of boehmite (boehmite C01, BET specific surface area 128 m ² / g, average primary particle diameter 30 nm, average secondary particle diameter 90 nm: manufactured by Daimei Chemical Industry Co., Ltd.) Except for the above, a glossy paper for inkjet was produced under the conditions described in Example 1.

(Example 6)
As a pigment for the ink receiving layer, vapor phase silica (HDK T30, BET specific surface area 300 m ² / g, average primary particle diameter 10 nm, average secondary particle diameter 150 nm: manufactured by Wacker) 55 parts by mass, monodisperse spherical colloidal silica 45 A glossy ink jet paper was produced under the conditions described in Example 1 except that the parts by mass (Snowtex AK-YL, average particle size 80 nm: manufactured by Nissan Chemical Industries, Ltd.) were used.

(Comparative Example 1)
A glossy paper for inkjet was produced under the conditions described in Example 1 except that the Beck smoothness of the paper base material was adjusted to 40 seconds in Example 1.

(Comparative Example 2)
A glossy paper for inkjet was produced under the conditions described in Example 1 except that the Beck smoothness of the paper base material was adjusted to 60 seconds in Example 1.

The following tests were carried out on the obtained glossy paper for inkjet, and the results are shown in Table 1.

(1) Measurement of Beck smoothness on the opposite surface of the ink receiving layer (glossy surface):
The measurement was carried out according to JIS-P8119.

(2) Reproducibility of glossy surface (ink receiving layer surface):
The mapability was measured in order to evaluate the mirror surface of the glossy surface of the obtained inkjet recording paper. The mapability was measured with a mapability measuring device (ICM-1T: manufactured by Suga Test Instruments Co., Ltd.) with an optical comb width of 2 mm and an input / reflection angle of 60 ° according to JIS H 8686-2. As an evaluation, when the reproducibility is 55% or more, the reflected image is clearly reflected and the glossiness is excellent. If it is less than 55%, the reflected image will be unclear and the glossiness will be poor.

(3) Ink absorbency of dye ink:
Using an inkjet printer "ENVY5530" manufactured by Hewlett-Packard Co., Ltd., using each CMYK ink, solid (100% density) and characters of each CMYK ink, and RGB (Red-Green-Blue) solid (100% density) and The characters were printed on the obtained inkjet recording paper. The boundary of each color in the solid part and the degree of bleeding of characters were visually evaluated.
⊚: The boundaries are clear, there is no bleeding, the characters are clear, and it is practical.
◯: Boundary bleeding is inconspicuous, characters are clear, and practical use is possible.
Δ: Boundary bleeding is conspicuous, characters are unclear, and there is a practical problem.
×: Boundary bleeding is so severe that characters cannot be identified and is practically impossible.

(4) Ink absorbency of pigment ink:
Using the Seiko Epson inkjet printer "PX-105" and using each CMYK ink, the solid (100% density) and characters of each CMYK ink and the solid (100% density) of RGB (Red-Green-Blue) ) And the characters were printed on the obtained inkjet recording paper. The boundary of each color in the solid part and the degree of bleeding of characters were visually evaluated.
⊚: The boundaries are clear, there is no bleeding, the characters are clear, and it is practical.
◯: Boundary bleeding is inconspicuous, characters are clear, and practical use is possible.
Δ: Boundary bleeding is conspicuous, characters are unclear, and there is a practical problem.
×: Boundary bleeding is so severe that characters cannot be identified and is practically impossible.

(5) Printer transportability:
Five sheets of the obtained glossy paper for inkjet (leaf size) are set in a reverse paper feed type inkjet printer (brother DCP-J940N, manufactured by Brother Industries, Ltd.) to print on the glossy surface, and this is repeated 100 times. , The number of double feeds was counted.
⊚: The number of double feeds is 0, and it can be put into practical use.
◯: It can be put into practical use when the number of double feeds is 1 to 2 times.
Δ: The number of double feeds is 3 to 5, which poses a practical problem.
X: The number of double feeds is 6 or more, which is practically impossible.

ベック平滑度（秒）（１）：インク受容層用塗工液を塗工する前の、塗工予定面の反対面の紙基材のベック平滑度
ベック平滑度（秒）（２）：キャストコート処理後の、インク受容層を設けた面の反対面のベック平滑度

Beck smoothness (seconds) (1): Beck smoothness of the paper substrate on the opposite side of the planned coating surface before applying the ink receiving layer coating liquid Beck smoothness (seconds) (2): Cast Beck smoothness on the opposite side of the surface with the ink receiving layer after coating

As is clear from Table 1, Examples 1 to 6 were superior in printer transportability as compared with Comparative Examples 1 and 2.

In Comparative Examples 1 and 2, since the Beck smoothness on the surface opposite to the ink receiving layer exceeds 20 seconds,
The transportability was poor.

Claims (6)

In glossy inkjet paper in which an ink receiving layer containing a pigment and a binder is provided on one side of a paper base material.
The ink receiving layer contains a porous fine pigment having an average secondary particle diameter of 20 to 1000 nm as the pigment.
The opposite surface of the one side provided with the ink receiving layer is the surface of the paper base material or the size press processed surface, and the opposite surface is the calendar processed surface.
The reproducibility of the ink receiving layer is 55% or more under the condition of an optical comb width of 2 mm and an input reflection angle of 60 ° according to JIS H 8686-2: 1999 “Method for reproducibility test of anodized film of aluminum and aluminum alloy”. A glossy paper for inkjet, wherein the Beck smoothness of the opposite surface is 5 seconds or more and 20 seconds or less. The porous fine pigment is one or more selected from vapor phase silica, precipitated silica, γ-alumina, θ-alumina, boehmite (including pseudo-boehmite), and alumina-modified silica, and is the same as the porous fine pigment. The glossy paper for an inkjet according to claim 1, wherein the BET specific surface area is 100 to 400 m ² / g. The glossy paper for an inkjet according to claim 1 or 2, wherein the porous fine pigment has an average primary particle diameter of 5 to 30 nm. The glossy paper for an inkjet according to any one of claims 1 to 3, wherein monodisperse spherical colloidal silica is distributed on the outermost surface of the ink receiving layer. The glossy paper for an inkjet according to any one of claims 1 to 4, wherein the opposite side is the address side as a postcard paper. In a method for producing glossy paper for inkjet, in which an ink receiving layer containing a pigment and a binder is provided on one side of a paper base material.
Surface opposite to the surface to be the provision of the ink-receiving layer is a surface or size press treated surface of the paper substrate was adjusted Bekk smoothness of the opposite surface below 40 seconds 10 seconds by calender a paper The process of preparing the material and
A coating liquid for an ink receiving layer containing the pigment and the binder and containing a porous fine pigment having an average secondary particle diameter of 20 to 1000 nm as the pigment is applied to the ink receiving layer of the paper substrate. The process of coating the surface to be provided to form a coating layer,
A coagulating liquid containing 5% by mass or more of the coagulant for coagulating the binder is applied to the cast drum while the coating layer is in a wet state to perform a coagulation treatment. It has a process of pressure welding,
The imageability of the ink receiving layer after undergoing the step is under the condition that the optical comb width is 2 mm and the reflection angle is 60 ° according to JIS H 8686-2: 1999 “Method for testing the image quality of anodized film of aluminum and aluminum alloy”. A method for producing glossy paper for an inkjet, wherein the Beck smoothness of the surface opposite to the surface provided with the ink receiving layer is 55% or more and 5 seconds or more and 20 seconds or less.