JP2010111067A - Method for manufacturing recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the occurrence of the pasting of a recording medium to a mirror-finished drum without cutting off unevenness generated at both ends of the recording medium by using a stacker, when manufacturing the recording medium by a re-wet cast method. <P>SOLUTION: The method for manufacturing the recording medium includes: a process for forming a porous ink accepting layer by coating a coating solution containing pigments and a binder on a support; a process for keeping the porous ink accepting layer in a wet state by coating a re-wet solution on the porous ink accepting layer; and a process for dying the porous ink accepting layer in the wet state by making the porous ink accepting layer pressure-contact with the mirror-finished drum by a pressingly contacting roll and then for peeling it from the mirror-finished drum, wherein the support is highly permeable and keeps no porous ink accepting layer present at both ends located with respect to the longitudinal direction of the surface of the recording medium at the pressure-contact of the recording medium with the mirror-finished drum. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a recording medium.

  The ink jet recording method records images, characters, and the like by causing micro droplets of a recording liquid (recording liquid) such as ink to fly by various operating principles and adhere to a recording medium such as paper. In recent years, it has been demanded that an image comparable to silver salt photography or plate-making multicolor printing is easily output by an ink jet recording method. Therefore, an attempt has been made to obtain a recorded image with excellent image characteristics by controlling the characteristics of a recording medium on which recording is performed by the inkjet recording method.

  In particular, in recent years, high surface gloss has been required as one of the image characteristics of recording media. As a method for imparting surface gloss to a recording medium, a casting method is often used to satisfy both surface gloss and ink absorbency at the same time.

  Patent Document 1 discloses that excellent surface gloss can be obtained without causing a decrease in ink absorbency by coating and forming an ink receiving layer containing a pigment by a rewet cast method.

  In addition, according to the casting method, the releasability between the recording medium and the mirror drum (cast drum) may not be good. In this case, a situation occurs in which the recording medium is stuck on the mirror drum and it is difficult to operate continuously for a long time.

  On the other hand, Patent Document 2 discloses a recording medium in which an ink receiving layer is provided on a highly permeable support having a low sizing degree in order to improve ink absorbability.

In addition, as a photographic paper support, a method in which a specific compound is contained in the support is known as a method for preventing the penetration of the developer from the side of the support. For example, Patent Document 3 discloses a photographic printing paper support in which the support contains a copolymer of an acrylamide compound and a diallylamine salt.
JP 2001-138628 A JP-A-9-66663 JP-A-7-120874

  In order to use a rewet cast method to impart high surface gloss and to provide a method for producing a high-quality recording medium with higher productivity, it is necessary to solve the following problems with respect to the prior art.

  In the method of Patent Document 1, a die coat is used for forming the ink receiving layer.

  Such a recording medium is collected in the form of a winding roll from the viewpoint of productivity and workability. At this time, as shown in FIG. 1 (A), both ends 1 are cut off by the slitter 2 before winding into a roll shape, the roll width is adjusted to a desired size, and finally shown in FIG. 1 (B). Take up as a form. This is because if there are portions where the porous ink receiving layer does not exist at both ends of the ink receiving layer surface in the longitudinal direction and the vertical direction, the ink receiving layer may be blurred after drying. This irregularity causes wrinkles when pressed against a mirror drum (cast drum) in rewetting cast, and the mirror drum surface cannot be copied sufficiently, resulting in a decrease in surface quality, or a portion of wrinkles that has occurred. It was a trouble because it cut out of the paper and caused a paper break. In this way, generally, if uncoated parts that are not coated with the coating liquid are disposed at both ends positioned in a direction perpendicular to the longitudinal direction of the support, the rewet casting method may cause trouble, Specifically, it was wound up in the form as shown in FIG. That is, in the conventional method, it is necessary to remove the uncoated portion of the recording medium once by a slitter. After that, after applying a coating liquid such as a rewet cast liquid on the ink receiving layer, the recording medium is applied to a mirror drum (cast drum). After press-contacting and drying, it was wound up into a roll. However, this method has a problem that further improvement is desired in terms of productivity in terms of cost and the like because both ends are cut off by a slitter in the previous process of rewet casting.

  On the other hand, Patent Document 2 discloses a recording medium in which an ink receiving layer is provided on a highly permeable support having a low sizing degree in order to improve ink absorbability.

  However, when a highly permeable support having a low sizing degree is used, the liquid may permeate from the side surfaces at both ends of the highly permeable support in the casting process. As a result, the moisture of the permeated liquid becomes excessive, and the recording medium and the mirror drum (cast drum) stick to each other.

  For this sticking, Patent Document 3 discloses a support for photographic paper containing a copolymer of an acrylamide compound and a diallylamine salt, and can suppress permeation from the side of the support. Was the way. However, when these compounds are applied to a highly permeable support having a low sizing degree, not only the end of the highly permeable support but also the liquid permeability of all parts of the highly permeable support is suppressed. Become. As a result, the ink absorbability of the entire recording medium is reduced.

  As described above, according to the conventional method, it has been necessary to remove the recording medium in which the unevenness has occurred by slit processing in the previous process of rewet casting. In the case of a recording medium using a highly permeable support, the liquid may permeate from both side surfaces of the recording medium at the stage of applying the rewet cast treatment. For this reason, even if it is a case where a drying process is given at a later process, drying may be in a state where drying is partially insufficient. It is known that the internal strength, tensile strength, tear strength, etc. of a highly permeable support generally decrease in a wet state where drying is insufficient. Further, when the ink receiving layer of the recording medium is in a wet state, the surface of the coating layer is likely to stick to the mirror drum (cast drum) due to the action of a binder component or the like present in the coating layer. As a result of the decrease in strength due to the wet state as described above, the coated paper adheres to the mirror drum (cast drum) on the surface of the coating layer, cuts the coated paper, and stains on the mirror drum (cast drum). There is a problem of occurrence.

  An object of the present invention is to solve the above-described problem, and is to suppress sticking to a mirror drum (cast drum) without cutting a blur part with a slitter in a process preceding the rewet casting process. . That is, the present invention provides a method for producing a recording medium that has both high surface glossiness, high productivity, and a high-quality recording medium.

  The present inventors have studied the above problems. A recording medium obtained from a coater head with a limited coating width has uncoated portions with unevenness at both ends. As a result, when applied to the rewetting cast method, wrinkles are generated when pressed against the mirror drum (cast drum), and the mirror drum surface cannot be copied sufficiently, leading to a reduction in surface quality. Or it will result from cutting off the generated wrinkles and causing paper breaks. Therefore, it was examined whether the blurring could be suppressed by some pretreatment. For example, an investigation was made as to whether or not the blur could be improved by applying moisture to the rewetting liquid applied to the recording medium.

  However, the rewet cast method usually performs processing in a short time in consideration of productivity. Therefore, it is desirable to treat the ink receiving layer by plasticizing the ink receiving layer while minimizing the amount of moisture applied. That is, an effect cannot be expected with a small amount of water, and therefore, suppression of blurring using a large amount of water is in conflict with the advantages of the rewet casting method, and application is not desirable.

  On the other hand, in order to improve the ink absorbability of the recording medium, it has been studied to perform a rewet cast process using a highly permeable support. According to the conventional rewet cast method, there is a problem that the liquid permeates from both side surfaces of the recording medium and the moisture content increases. In order to solve this problem, the introduction of a coater head capable of limiting the coating width of the rewetting liquid was examined. However, there is a problem that a new capital investment is required and a liquid having a low viscosity such as water has a problem that it is difficult to limit the coating width.

  In view of these problems, the present inventors have conducted further detailed studies, and as a result, have found the following present invention.

  When a recording medium having a highly permeable support having a low degree of size is used in the rewet casting method, the rewet liquid is easily absorbed from both side surfaces. However, in this case, when a recording medium having an uncoated part is used for the rewet casting method, even if the exposed surface of the uncoated part absorbs moisture and has a high water content, a mirror drum (cast drum) It was found that sticking to the surface is reduced. Furthermore, it has been found that process troubles such as paper breaks caused by unevenness occurring at both ends of the coated paper can be extended with moisture application to the support.

  That is, the present invention includes a step of applying a coating liquid containing a pigment and a binder on a support to form a porous ink receiving layer, and applying a rewetting liquid on the porous ink receiving layer to form a porous layer. A recording medium comprising: a step of bringing a wet ink receiving layer into a wet state; and a step of pressing the wet porous ink receiving layer against a mirror drum with a press roll and drying, followed by peeling off from the mirror drum In the manufacturing method, the support is a highly permeable support, and when the recording medium is pressed against the mirror drum, both ends positioned perpendicular to the longitudinal direction of the recording medium surface are A method for producing a recording medium, wherein a porous ink-receiving layer is not present.

  According to the present invention, it is not necessary to cut off the uneven portion with a slitter in a process preceding the rewet casting process. In addition, since it is possible to suppress sticking to a mirror drum (cast drum), the recording medium combines high surface glossiness, high productivity, and a high-quality recording medium. The manufacturing method can be provided.

  The manufacturing method of the recording medium of the present invention includes the following steps. A step of forming a porous ink receiving layer by applying a coating liquid containing a pigment and a binder on a support. Applying a rewetting liquid onto the porous ink receiving layer to wet the porous ink receiving layer; In this step, the wet porous ink-receiving layer is pressed against a mirror drum with a pressure roller and dried, and then peeled off from the mirror drum.

  In particular, in the present invention, the porous ink receiving layer is formed on the highly permeable support using a coater head having a coating width narrower than that of the highly permeable support. The reason why the coating width is narrower than that of the highly permeable support is as follows. That is, when the recording medium is brought into pressure contact with the mirror drum, if there are porous ink receiving layers at both ends positioned perpendicular to the longitudinal direction of the recording medium surface, the rewetting liquid permeates from both side surfaces, and the porous The pulp layer located below the quality ink receiving layer is in a high water content state. As a result, even if the drying process is performed in a later step, the pulp layer is in a highly water-containing state. Therefore, even if the drying time is the same, the drying is insufficient compared to the surroundings, and it acts on the binder component and the like present in the porous ink receiving layer located at the upper layer, so that the porous ink receiving layer The surface becomes easy to stick to the mirror drum (cast drum). Furthermore, problems such as cutting of the recording medium and contamination of the mirror drum (cast drum) tend to occur.

  Each step of the recording medium manufacturing method of the present invention will be described in detail.

(A) Surface treatment process of highly permeable support body First, a support body is prepared. In the present invention, the support is a highly permeable support. By using a highly permeable support, ink absorbability is improved. In addition, wrinkles caused by unevenness at both ends positioned in a direction perpendicular to the longitudinal direction of the recording medium can be avoided by a short rewetting liquid coating process. A highly permeable support refers to a support having a low degree of steecht size. A highly permeable support refers to a support having a Steecht sizing degree of 150 seconds or less. The Steecht sizing degree is more preferably 100 seconds or less, and further preferably 30 seconds or less. As the highly permeable support, a highly permeable support having desired characteristics may be prepared from the material for the highly permeable support, or a commercially available highly permeable support may be used.

  The highly permeable support used in the present invention is made of an opaque material and has air permeability. In particular, a fibrous support, that is, a highly permeable support made of paper, is comparable to a silver salt photograph by forming a porous ink receiving layer on this support and then performing a gloss treatment such as casting. It is preferable because high surface gloss can be obtained.

As the highly permeable support made of this paper, starch, polyvinyl alcohol, or other size press applied to the base paper, or art paper, coated paper, cast coated paper, etc., provided with a coat layer on the base paper Paper or the like may be used. Preferably, a highly permeable support made of paper is provided with a coating layer having a thickness that covers the cellulose pulp fibers and texture of the paper (base paper) as a porous ink receiving layer and an undercoat layer of the surface treatment liquid. Is good. When the highly permeable support is not covered with the coating layer as described above, coating unevenness (streak) caused by fibers or texture of the highly permeable support is applied when the coating liquid for the porous ink receiving layer is applied. Unevenness etc.) is likely to occur. In addition, cellulose pulp fibers are present in the inside / near surface of the porous ink receiving layer or in the surface. For this reason, even if the rewet cast method is applied to the surface of the coated paper, it may be difficult to obtain a good and homogeneous cast surface, that is, a photographic tone high gloss surface. In order to cover the cellulose pulp of the highly permeable support made of paper, the dry coating amount of the coat layer is preferably 10 g / m ² or more, more preferably 13 g / m ² or more.

  The air permeability of the highly permeable support made of paper is preferably 6000 seconds or less, and more preferably 5500 seconds or less from the viewpoint of suitability for gloss treatment in the gloss treatment step described later.

  When a highly permeable support having an undercoat layer is used, it is preferable that the steecht degree of the highly permeable support having an undercoat layer is 400 seconds or less. The Beck smoothness is preferably 100 seconds or more and 500 seconds or less, and the underwater elongation is 1.2% or more and 4.0% or less.

Further, in order to obtain a recording medium having the same texture and luxury as silver halide photography, a highly permeable support, a basis weight of 130 g / m ^{2 to} 400 g / m ² and Gurley stiffness (J. Tappi No. 40). , Longitudinal) is preferably 7 to 15 mN.

Next, a surface treatment liquid is applied onto the highly permeable support. In this step, a surface treatment liquid containing at least one of boric acid and borate is applied onto a highly permeable support (in some cases, a highly permeable support provided with a coating layer). The coating amount of the surface treatment solution is preferably in terms of solid content of boric acid and borate is 0.05 g / ^{m 2} or more 3.0 g / ^{m 2} or less.

  The surface treatment liquid may contain a crosslinking agent that cures by causing a crosslinking reaction with the binder. By using this cross-linking agent, it is preferable to use a porous ink receiving layer to be formed later on a highly permeable support in a desired structure more effectively.

  The content of the crosslinking agent in the surface treatment liquid is preferably 1% by mass or more and 10% by mass or less. Further, in order to improve the wettability of the surface treatment liquid, a surfactant, alcohol, or the like may be added to the surface treatment liquid to adjust the surface tension and water absorption.

  This surface treatment may be performed only on one side of the support or on both sides. When the back layer is provided on the back side of the highly permeable support (the side opposite to the side where the ink receiving layer is provided), it is preferable to perform surface treatment on both sides of the highly permeable support.

  Various coating apparatuses can be used for coating the surface treatment liquid so that an appropriate coating amount can be obtained. As this coating apparatus, various blade coaters, roll coaters, air knife coaters, bar coaters, rod blade coaters, curtain coaters, gravure coaters, coaters using an extrusion method, coaters using a slide bead method, etc. are used. be able to. These coating apparatuses can be appropriately selected and used on-machine and off-machine. Further, at the time of coating such as a size press, the surface treatment liquid may be heated for the purpose of adjusting the viscosity of the surface treatment liquid or the like, and the coater head can also be heated.

  Also, for drying the surface treatment liquid after coating, a dryer using a hot air dryer such as a straight tunnel dryer, arch dryer, air loop dryer, sine curve air float dryer, infrared ray, heated dryer, microwave, etc. Etc. can be appropriately selected and used.

  In the above “(A) Surface treatment step of highly permeable support”, an example in which surface treatment was performed was described. However, depending on the constituent material of the highly permeable support and porous ink receiving layer, the surface treatment was performed. It is not necessary.

(B) Porous ink receptive layer forming step Next, a coating liquid for a porous ink receptive layer containing at least a pigment and a binder is applied and dried on the surface-treated highly permeable support. Thus, a porous ink receiving layer is formed.

  The material for forming the porous ink receiving layer used in the present invention will be described below. The porous ink receiving layer can be formed by applying a coating liquid containing a pigment and a binder on a highly permeable support.

  For example, the inorganic pigment is preferably light calcium carbonate, heavy calcium carbonate, magnesium carbonate, kaolin, aluminum silicate, diatomaceous earth, calcium silicate, magnesium silicate, synthetic amorphous silica, colloidal silica, alumina, magnesium hydroxide and the like. As the organic pigment, styrene plastic pigment, acrylic plastic pigment, polyethylene particles, microcapsule particles, urea resin particles, melamine resin particles and the like are preferably used. These pigments can be used alone or in combination of two or more selected from the above-mentioned pigments.

Further, as the pigment, alumina hydrate represented by the following general formula (X) can be suitably used in terms of dye fixing property, transparency, printing density, color developability, and gloss.
Al ₂ O _3-n (OH) _2n · mH ₂ O (X)
(In the above formula, n represents any of 0, 1, 2, or 3, and m represents a value in the range of 0 to 10, preferably 0 to 5. However, m and n are not 0 at the same time. MH ₂ O often represents a detachable aqueous phase that is not involved in the formation of the crystal lattice, so m can take an integer or non-integer value. When heated, m can reach a value of 0).

  As the crystal structure of this alumina hydrate, the amorphous, kibsite-type, boehmite-type aluminum hydroxide transitions from γ, σ, η, θ, α-type aluminum oxide depending on the heat treatment temperature. It is known to go. In the present invention, an alumina hydrate having any of these crystal structures may be used.

  Examples of the alumina hydrate suitable for use in the present invention include alumina hydrate exhibiting a boehmite structure or an amorphous state by analysis by an X-ray diffraction method. Specifically, such alumina hydrates are described in JP-A-7-232473, JP-A-8-132731, JP-A-9-66664, JP-A-9-76628, and the like. Mention may be made of alumina hydrate.

  This alumina hydrate can adjust pore physical properties during the production process. Specifically, in order to make the porous ink receiving layer have a desired BET specific surface area and pore volume, alumina hydrate having a pore volume of 0.3 ml / g or more and 1.0 ml / g or less is used. Is preferred. It is more preferable to use alumina hydrate having a pore volume of 0.35 ml / g or more and 0.9 ml / g or less. By using alumina hydrate having a pore volume in these ranges, the porous volume of the porous ink receiving layer is set to a desired range, and the porous ink receiving layer is excellent in ink absorbability and ink fixability. It can be.

Also, the BET specific surface area, it is preferable to use a ^{50 m} 2 / g or more 350 meters ² / g or less of the alumina hydrate, it is preferable to use the following alumina hydrate 100 m ² / g or more 250 meters ² / g . By using these alumina hydrates in the BET specific surface area range, the porous ink receiving layer has a desired specific surface area of the porous ink receiving layer, and is a porous ink receiving layer excellent in ink absorbability and ink fixing property. be able to.

  The “BET method” referred to in the present invention is one of the powder surface area measurement methods by the vapor phase adsorption method, and is a method for obtaining the total surface area, that is, the specific surface area of a 1 g sample from the adsorption isotherm. . As this adsorbed gas, nitrogen gas is usually used, and the method of measuring the amount of adsorption from the change in pressure or volume of the gas to be adsorbed is most often used. The most prominent expression for representing the isotherm of multimolecular adsorption is the Brunauer, Emmett, and Teller equation, called the BET equation, which is widely used for determining the specific surface area. In the BET method, the specific surface area can be obtained by calculating the amount of adsorption based on this BET formula and multiplying the area occupied by one adsorbed molecule on the surface.

  The shape of the alumina hydrate is preferably a flat plate having an average aspect ratio of 3 to 10 and an aspect ratio of the flat plate surface of 0.6 to 1.0. The “average aspect ratio” can be obtained by the method described in Japanese Patent Publication No. 5-16015. That is, the average aspect ratio is represented by the ratio of the “diameter” to the “thickness” of the particles. Here, the “diameter” represents the diameter of a circle having an area equal to the projected area of the particles when the alumina hydrate is observed with a microscope or an electron microscope. The aspect ratio of the flat plate surface is the ratio of the diameter indicating the minimum value of the flat plate surface and the diameter indicating the maximum value when the particles are observed with a microscope, like the average aspect ratio. When alumina hydrate having an average aspect ratio of less than 3 is used, the pore distribution range of the porous ink receiving layer may become narrow depending on the constituent material of the porous ink receiving layer. In addition, when an alumina hydrate having an average aspect ratio exceeding 10 is used, it may be difficult to produce the alumina hydrate with the same particle diameter. Further, when alumina hydrate having an aspect ratio of 0.6 or more and 1.0 or less is used, the pore size distribution of the porous ink receiving layer may be narrowed.

  Rocek J. et al. , Et al. As disclosed in Applied Catalysis, Vol. 74, p. 29-36, 1991, it is generally known that some alumina hydrates are ciliated and flat. Here, it is preferable to use a plate-like alumina hydrate as the alumina hydrate. The plate-like alumina hydrate is more dispersible than the ciliated alumina hydrate. In addition, ciliary alumina hydrate tends to be oriented parallel to the surface of the support during coating. In this case, the pores of the porous ink receiving layer become smaller and the porous ink receiving layer becomes smaller. The ink absorbency of the layer may be reduced. On the other hand, the plate-like alumina hydrate has a small tendency to be oriented, and the pore diameter of the porous ink receiving layer is not reduced and the ink absorbability is not reduced.

  As the binder for the porous ink receiving layer, any material can be used without particular limitation as long as it is a material capable of binding the pigment and forming a film and does not impair the effects of the present invention. Can do. Examples of the binder include starch derivatives such as oxidized starch, etherified starch and phosphate esterified starch, cellulose derivatives such as carboxymethylcellulose and hydroxyethylcellulose, casein, gelatin, soy protein, polyvinyl alcohol or derivatives thereof, polyvinylpyrrolidone, anhydrous Conjugated polymer latex such as maleic acid resin, styrene-butadiene copolymer, methyl methacrylate-butadiene copolymer, acrylic ester polymer, methacrylic ester polymer or acrylic ester and methacrylic ester copolymer Functional polymer-modified latex with functional group-containing monomers such as carboxyl groups of the above-mentioned various polymers, acrylic polymer latex such as ethylene-vinyl acetate copolymer, The body is cationized with a cationic group, the surface of the polymer is cationized with a cationic surfactant, the polymer is polymerized with cationic polyvinyl alcohol, and the polyvinyl alcohol is distributed on the polymer surface, the cation Polymerization is performed in a suspension dispersion of curable colloidal particles, the particles are distributed on the polymer surface, an aqueous binder such as a thermosetting synthetic resin such as melamine resin and urea resin, and an acrylic such as polymethyl methacrylate. Synthetic resin binders such as acid ester and methacrylic acid ester polymers or copolymer resins, polyurethane resins, unsaturated polyester resins, vinyl chloride-vinyl acetate copolymers, polyvinyl butyral, alkyd resins, and the like can be used. The above binders can be used alone or in combination.

  The binder content in the porous ink receiving layer is preferably 5 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the pigment. When the binder content is less than 5 parts by mass, cracks are likely to occur in the porous ink-receiving layer, and the mechanical strength of the porous ink-receiving layer becomes insufficient, and powder falling tends to occur. Further, when the binder content exceeds 50 parts by mass, the ink absorbability may be reduced (for example, ink overflow or image bleeding) or the ink dye adsorbability may be decreased. Furthermore, in order to obtain sufficient ink absorbency even under high temperature and high humidity, the binder content is more preferably 5 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the pigment.

The inclusion of at least one of boric acid and borate in the porous ink receiving layer is extremely effective in forming the porous ink receiving layer. Examples of the boric acid include orthoboric acid (H ₃ BO ₃ ), metaboric acid and diboric acid. The borate is preferably a water-soluble salt of boric acid, specifically, for example, sodium salt of boric acid (Na ₂ B ₄ O ₇ · 10H ₂ O, NaBO ₂ · 4H ₂ O, etc. ) and, potassium salt _{(K 2 B 4 O 7 ·} 5H 2 O, alkali metal salts such KBO _2, etc.), an ammonium salt of boric acid _{(NH 4 B 4 O 9 ·} 3H 2 O, NH 4 BO 2 , etc.) And magnesium salts of boric acid and calcium salts.

  Among these boric acids and borates, it is preferable to use orthoboric acid from the viewpoint of the temporal stability of the coating solution and the effect of suppressing the occurrence of cracks. The boric acid and borate content in the porous ink receiving layer is 1.0 in terms of solid content of boric acid and borate with respect to 100 parts by mass of the binder in the porous ink receiving layer. It is preferable to use in the range of no less than 15.0 parts by mass. When it exceeds 15.0 mass parts, the temporal stability of a coating liquid may fall. In other words, when the coating liquid is used for a long time, the viscosity of the coating liquid or gelled product is generated during that time, and it is necessary to frequently change the coating liquid or clean the coater head. Productivity may be significantly reduced.

  Further, a colorant deterioration preventing agent may be added to the porous ink receiving layer. The color material deterioration preventing material refers to a compound that is present together with a dye in the porous ink receiving layer to prevent deterioration of the dye due to gas and light, and to improve the weather resistance of the dye. Examples of the colorant deterioration preventing agent include hindered amine compounds, hindered phenol compounds, benzophenone compounds, benzotriazole compounds, thiourea compounds, thiuram compounds, phosphite compounds, and the like. It is not limited. Among these color material deterioration inhibitors, hindered amine compounds can be preferably used.

  As a method for adding the color material deterioration preventing agent to the recording medium, the color material deterioration preventing agent and the color material deterioration preventing agent are dissolved on a porous ink receiving layer previously formed on a highly permeable support. A method of overcoating a preparation solution containing a solvent is preferred. The solvent is not particularly limited as long as it dissolves the colorant deterioration preventing agent, and various solvents can be used. Examples of organic solvents include esters such as ethyl acetate and butyl acetate, ketones such as methyl isobutyl ketone, methyl ethyl ketone and acetone, ethers such as diethyl ether and ethyl methyl ether, alcohols such as isopropanol, methanol and ethanol. Can be mentioned.

  Further, the timing of overcoating the preparation liquid containing the colorant deterioration preventing agent on the porous ink receiving layer is not particularly limited as long as it is after the formation of the porous ink receiving layer. However, when overcoating is performed in such a manner that the coating member is in contact with the surface of the porous ink receiving layer, the surface of the porous ink receiving layer may be damaged during the overcoating step. For this reason, it is preferable to perform overcoating before performing the gloss treatment with a mirror drum (cast drum) in the rewet casting method.

  In the coating liquid for the porous ink receiving layer, for example, formic acid, acetic acid, glycolic acid, oxalic acid, propionic acid, malonic acid, succinic acid, adipic acid, maleic acid, malic acid, tartaric acid , Organic acids such as citric acid and benzoic acid, organic acids such as phthalic acid, isophthalic acid, terephthalic acid, glutaric acid, gluconic acid, lactic acid, aspartic acid, glutamic acid, pimelic acid, suberic acid, hydrochloric acid, nitric acid, phosphoric acid, etc. An inorganic acid, a salt of the above acid, or the like can be appropriately added.

  Other additives for the coating liquid for porous ink-receiving layer include pigment dispersants, thickeners, fluidity improvers, antifoaming agents, antifoaming agents, mold release agents, penetrating agents, and coloring pigments. , Coloring dyes, fluorescent brighteners, ultraviolet absorbers, antioxidants, preservatives, antifungal agents, water resistance agents, dye fixing agents, curing agents, and weathering materials can be appropriately contained as necessary. .

  The coating liquid for the porous ink receiving layer can be prepared, for example, as follows. That is, first, a dispersion containing alumina hydrate and, if necessary, a crosslinking agent is prepared. Next, a liquid mixture obtained by mixing at least one of boric acid and borate with this dispersion liquid and a binder aqueous solution or binder dispersion liquid are mixed immediately before coating to prepare a porous ink receiving layer. Use as coating liquid. It is preferable to use a mixing device for mixing the mixed solution with the binder aqueous solution or binder dispersion. By preparing the coating liquid for the porous ink receiving layer by the above procedure, it is possible to improve the production efficiency by reducing the increase in the viscosity of the coating liquid over time and the gelation in the production process.

  In addition, as a continuous preparation method of the coating liquid in an actual process, a method in which pigments and binders are supplied from separate lines and mixed using a continuous mixing device such as a static mixer is mentioned. Can do. In this method of preparing the coating liquid, cracks can be prevented during coating and drying, and the binding strength of the porous ink receiving layer can be increased. Moreover, when adding a crosslinking agent etc. in a coating liquid, since it becomes easy to thicken at the time of preparation / liquid feeding of a coating liquid, the said method can be used preferably.

  Here, the static mixer refers to a structure in which a mixing unit is housed in a hollow cylindrical frame. In this mixing unit, a plurality of elements are connected in the longitudinal direction, and one element has a shape that is twisted, for example, 180 degrees in the circumferential direction as the plate body is advanced in the longitudinal direction. The twisting directions of adjacent elements are opposite to each other. In this apparatus, the coating liquid for the porous ink receiving layer is uniformly mixed by each element while flowing in the frame.

  The solid content concentration of alumina hydrate in the dispersion is preferably 10% by mass or more and 30% by mass or less. If the solid content concentration of the alumina hydrate exceeds 30% by mass, the viscosity of the dispersion increases, and the viscosity of the coating liquid increases, which may cause problems in coating properties.

  Next, the coating liquid for the porous ink receiving layer thus prepared is applied on the surface of the highly permeable support that has been surface-treated. As the coating apparatus for the coating liquid for the porous ink-receiving layer, the coating apparatus for the surface treatment liquid described in the above “(A) Surface treatment step of the highly permeable support” can be used.

  In particular, in the present invention, when the recording medium is brought into pressure contact with the mirror drum, it is necessary to dispose uncoated portions where the ink receiving layer does not exist at both ends positioned perpendicular to the longitudinal direction of the recording medium surface. is there. Therefore, a system capable of limiting the coating width, such as a coater using an extrusion system and a coater using a slide bead system, is preferably used.

  The width of the uncoated portion can be appropriately adjusted so as not to cause sticking depending on the sizing degree of the high permeability support used, the processing speed, and the like. For example, if the Steecht sizing degree is 30 seconds or less, when the rewetting liquid is applied to the coated paper, the width of one side of the portion of the recording medium that penetrates from both side surfaces and remains high in moisture after drying is reduced. About 1 mm to 10 mm from the end. Accordingly, the width of the uncoated portion is preferably wider than this highly water-containing portion, and it is preferable that both ends are adjusted to about 2 mm to 85 mm from the end of the recording medium. If the uncoated portion is narrower than 2 mm, the effect of preventing sticking may not be obtained, and if it is wider than 85 mm, the productivity is lowered, which is not preferable.

  As a preferred form, the portions where the porous ink receiving layer is not present at both ends located in the direction perpendicular to the longitudinal direction of the surface of the recording field are at least 2 mm from the end of the recording medium at both ends. It is. Moreover, 5 mm or more is more preferable and 15 mm or more is more preferable. When the porous ink-receiving layer is formed by setting the thickness to 2 mm or more, the highly permeable support is transported on the apparatus, and even if there is a slight left / right misalignment, the coating width is high permeable support. Protruding from above can be suppressed. Moreover, it is preferable from the point of productivity to set it as 85 mm or less. Furthermore, it is preferable to set it as 40 mm or less.

  The uncoated portion of the ink receiving layer of the present invention is preferably in a state where sticking is suppressed even in a wet state. For example, compared to the pigment used for the porous ink receiving layer, when using a large particle size on the exposed surface such as the undercoat layer located in the uncoated part, the surface area is small, so it is difficult to stick. Tend to be. Alternatively, it is also preferable to use a latex that is difficult to swell or re-dissolve by rewetting as the binder.

  As a drying apparatus after coating the coating liquid, the drying apparatus for the surface treatment liquid described in the above-mentioned “(A) Surface treatment step of highly permeable support” can be used.

  The coating of the coating liquid for the porous ink-receiving layer is carried out by applying the surface treatment liquid onto the highly permeable support and then drying the surface of the highly permeable support without drying. It is preferable to carry out in a state in which a state or a thickened state may be maintained.

  The porous ink-receptive layer of the present invention has the following physical properties in terms of its pore properties in order to achieve the purpose and effect of the ink such as high-speed absorption, high color development, and high resolution. Preferably there is.

  The pore size distribution of the porous ink receiving layer preferably has a peak in a range of at least a pore radius of 5 nm or more and 20 nm or less. When the peak is in the range of the pore radius less than 5 nm, the high-speed absorbability of the ink may be inferior. In addition, when there is a peak in a range exceeding the pore radius of 20 nm, sufficient performance may not be obtained in terms of color developability and resolution.

The pore volume of the porous ink receiving layer is preferably in the range of 0.1 cm ³ / g to 1.0 cm ³ / g. When the pore volume is less than 0.1 cm ³ / g, a sufficient ink absorption performance cannot be obtained, resulting in a porous ink receiving layer with poor ink absorbability, and the ink may overflow and image bleeding may occur. In addition, when the pore volume exceeds 1.0 cm ³ / g, cracks and powder falling may easily occur in the porous ink receiving layer.

The BET specific surface area of the porous ink receiving layer is preferably 20 m ² / g or more and 450 m ² / g or less. When the BET specific surface area is less than 20 m ² / g, sufficient gloss may not be obtained, haze may increase (transparency may decrease), and the image may appear white and hazy. In this case, not only the color developability of the dye is lowered but also the dye adsorbability in the ink may be lowered. On the other hand, if the BET specific surface area exceeds 450 m ² / g, cracks are likely to occur in the porous ink receiving layer, such being undesirable. The values of the pore volume and the BET specific surface area are obtained by a nitrogen adsorption / desorption method.

The dry coating amount of the porous ink-receiving layer is preferably 30 g / m ² or more and 50 g / m ² or less. By setting the dry coating amount to 30 g / m ² or more, it is possible to obtain a porous ink receiving layer exhibiting sufficient ink absorbency even in a high temperature and high humidity environment. When the dry coating amount is 50 g / m ² or less, uneven coating of the porous ink receiving layer is less likely to occur, and a porous ink receiving layer having a stable thickness can be produced.

On the other hand, if the dry coating weight is less than 30 g / m ^2, on the recording medium, other cyan, magenta, yellow, black ink using a printer, when recording a plurality of light ink, sufficient ink absorbency May not be obtained. In addition, ink overflow may occur and bleeding may occur, or the ink dye may diffuse to the highly permeable support and the print density may decrease. Furthermore, when the dry coating amount exceeds 50 g / m ² , the occurrence of cracks may not be completely suppressed.

  Further, the ink receiving layer may be one layer or two or more layers.

(C) Back surface forming step In the present invention, if necessary, a coating liquid for the back surface layer is applied to the surface of the highly permeable support opposite to the side where the porous ink receiving layer is provided (back surface side). You may apply. The coating liquid for the back layer preferably contains at least a pigment and a binder. The coating solution for the back layer may contain a crosslinking agent that cures by causing a crosslinking reaction with the binder. The coating liquid for the porous ink receiving layer and the coating liquid for the back surface layer can be applied simultaneously on both surfaces of the highly permeable support.

  Thus, by providing a back layer on the back side of the highly permeable support, curling of the highly permeable support can be effectively prevented. If necessary, when the surface treatment is performed on the surface of the highly permeable support on which the porous ink-receiving layer is formed, the surface treatment may also be performed on the back surface of the highly permeable support. good.

  The coating liquid for the back layer can be prepared by mixing the pigment dispersion described in the above-described process for preparing the coating liquid for the porous ink receiving layer and the aqueous binder solution. Here, as the pigment to be contained in the coating solution for the back layer, it is preferable to use alumina hydrate for the same reason as described above. As this alumina hydrate, it is more preferable to use the one represented by the above general formula (X). As the binder, polyvinyl alcohol is preferably used for the same reason as described above.

  If necessary, a crosslinking agent and a pH adjuster can be added to the coating solution for the back layer. Examples of the pH adjuster include formic acid, acetic acid, glycolic acid, oxalic acid, propionic acid, malonic acid, succinic acid, adipic acid, maleic acid, malic acid, tartaric acid, citric acid, benzoic acid and other organic acids, phthalic acid And organic acids such as isophthalic acid, terephthalic acid, glutaric acid, gluconic acid, lactic acid, aspartic acid, glutamic acid, pimelic acid and suberic acid, inorganic acids such as hydrochloric acid, nitric acid and phosphoric acid, and salts of these acids. These acids can be used alone or in combination of two or more.

  Other additives include pigment dispersants, thickeners, fluidity improvers, antifoaming agents, antifoaming agents, mold release agents, penetrating agents, colored pigments, colored dyes, fluorescent whitening agents, UV absorbers Antioxidants, antiseptics, antifungal agents, water resistance agents, dye fixing agents, curing agents, weathering materials, and the like can be appropriately contained as necessary.

  The coating liquid for the back layer can be prepared as follows, for example. That is, first, a dispersion containing alumina hydrate and, if necessary, a crosslinking agent is prepared. Next, this dispersion liquid and the binder aqueous solution or binder dispersion liquid are mixed immediately before coating to obtain a coating liquid. It is preferable to use a mixing device for mixing the dispersion and the aqueous binder solution or binder dispersion. By preparing the coating solution by the above procedure, it is possible to improve the production efficiency by reducing the time-dependent increase in the viscosity of the coating solution and the gelation during the production process.

  The solid content concentration of alumina hydrate in the dispersion is preferably 10% by mass or more and 50% by mass or less. If the solid content concentration of the alumina hydrate exceeds 50% by mass, the viscosity of the dispersion increases and the viscosity of the back layer increases, which may cause problems in coating properties.

  Moreover, as a coating apparatus for the coating liquid for the back surface layer, the coating apparatus for the surface treatment liquid described in the above-mentioned “(A) Surface treatment step of highly permeable support” can be used. In addition, as a continuous supply method of the coating liquid to the coating apparatus in a process, the method as described in said "(B) Porous ink receiving layer formation process" can be mentioned. Moreover, as a drying apparatus after coating this coating liquid, the drying apparatus of the surface treatment liquid described in the above-mentioned “(A) Surface treatment process of highly permeable support” can be used.

  FIG. 2 shows a state before the recording medium of the present invention is pressed against the mirror drum. The direction of the arrow in FIG. 2D is the longitudinal direction of the recording medium surface. The recording medium has portions (6) where the porous ink receiving layer does not exist at both ends located in a direction perpendicular to the longitudinal direction.

(D) Rewetting Casting Process for Recording Field In the present invention, the rewetting liquid is applied from the rewetting liquid supply section to the porous ink receiving layer forming side while continuously transporting the recording medium. Further, while the porous ink receiving layer is in a wet state, the porous ink receiving layer is pressed against a mirror drum with a pressing roller and dried. Next, the recording field body is peeled off from the mirror drum.

  FIG. 3 is a diagram illustrating steps from application of a rewetting liquid to pressure contact of a mirror drum (cast drum) using a rewetting cast method, which is an example of a manufacturing method. After the rewetting liquid is applied to the surface of the recording medium having the uncoated portion of the ink receiving layer by the rewetting liquid supply unit 9, it is brought into pressure contact with the mirror drum (cast drum) 11 using the pressure contact roll 10 and heated. dry. Then, the recording medium 17 having uncoated portions at both ends after pressure contact and heat drying is peeled off from the mirror drum (cast drum) 11 by the take-off roll 12.

  In the process of FIG. 4, the rewetting liquid 16 penetrates from the end of the highly permeable support, and compared with the portion 15 where the coating liquid is applied to the surface of the coating layer, This means that the moisture content is high.

  The rewetting liquid used in the present invention is a treatment liquid applied on the porous ink receiving layer that develops gloss, and is mainly for the purpose of plasticizing the porous ink receiving layer. As this rewet solution, water or an aqueous solution containing a release agent such as polyethylene emulsion, fatty acid bib, calcium stearate, microcrystalline wax, surfactant, funnel oil or the like can be used. In the rewetting liquid, a release agent, a gloss imparting agent, a penetrating agent, a colorant, a pH adjusting agent, a cation agent, an ultraviolet absorber, an antioxidant, an antiseptic, a high-boiling solvent, an anti-pigmenting agent and the like are appropriately used. It can also be blended.

The rewetting liquid is applied to the coating layer so that the coating liquid contacts the side surface of the end of the coated paper. The coating method is not particularly limited, and it is a brush or sponge roller, various blade coaters, roll coaters, air knife coaters, bar coaters, rod blade coaters, curtain coaters, gravure coaters, and die coaters using an extrusion method. Various coating devices such as a coater, a coater using a slide hopper system, and a size press can be appropriately selected and used.
In the recording medium of the present invention, hydrated alumina is preferably used for the ink receiving layer. In this case, high gloss is obtained particularly by performing the rewet casting method, which is more preferable.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these. Various physical properties related to the present invention were measured by the following methods.

<Stick human sizing degree>
The recording medium was cut into A4 size, and the five sheets were left to stand for 2 hours or more under conditions of an air temperature of 23 ° C. and a humidity of 50%. Thereafter, in accordance with JIS P8122, the Steecht sizing degree was measured for each sheet, and the average value of five sheets was obtained.

<BET specific surface area and pore volume of alumina hydrate>
The alumina hydrate was sufficiently heated and degassed, and then measured using an apparatus using a nitrogen adsorption / desorption method (manufactured by Cantachrome, Autosorb 1). For the calculation of the BET specific surface area, the method of Brunauer et al. Was used (see J. Am. Chem. Soc., 60, 309, 1938). The method of Barrett et al. Was used to calculate the pore volume (see J. Am. Chem. Soc., 73, 373, 1951).
<Crack>
The recording medium was cut into 5 sheets of A4 size and evaluated visually. Primary evaluation was made with ○ indicating that no crack was observed on the surface of the coating film, and × indicating that a crack having a width of about 1 mm was recognized on the surface of the coating film. Next, the results of the secondary evaluation are shown in Table 1 when the results of the primary evaluation of the 5 sheets are 3 or more and ○ when the result is ◯, and otherwise.
<Printability>
The recording medium was cut into 5 sheets of A4 size, and each was printed with an inkjet printer iP8600 (manufactured by Canon Inc.). The print density of a solid image printed with a single Bk ink and an ink amount of 100% was evaluated using a Macbeth reflection densitometer RD-918. Table 2 shows the average of 5 sheets rounded to the first decimal place.
<Manufacturing aptitude>
The rewet cast method was evaluated in terms of productivity such that the yield in the A4 size with respect to the longitudinal direction and the vertical direction of the surface of the recording medium, and the L size can be additionally created. In addition, when the recording medium is pressed against the mirror drum (cast drum) and then peeled off, the drum becomes dirty due to sticking of the coated paper to the mirror drum (cast drum), or the coated paper is cut off. Alternatively, in terms of process troubles such as a decrease in surface area of the recording medium surface, the evaluation was comprehensively performed according to the following evaluation criteria.
◯: In addition to the A4 size of 4 exactly, the L size size could be additionally cut out with respect to the longitudinal direction and the vertical direction of the surface of the recording medium. Further, the recording medium did not stick to the mirror drum.
Δ: Four A4 sizes could be cut out in the direction perpendicular to the longitudinal direction of the recording medium surface. A little sticking of the recording medium to the mirror drum occurred, but no paper breakage or deterioration of the surface property of the recording medium surface occurred.
X: Drum contamination, paper breakage, surface deterioration of the recording medium surface, etc. occurred.

  In order to make the cutout size accurate when sampling, an interval of about several centimeters is provided as a margin between adjacent recording media.

Example 1
<Preparation of highly permeable support>
First, a pulp slurry having the following composition was prepared.
90 parts by mass of hardwood bleached kraft pulp (LBKP) having a freeness of 400 mlCSF 10 parts by weight of softwood bleached kraft pulp (NBKP) having a freeness of 350 mlCSF.

Next, 10 parts by weight of light calcium carbonate and 0.1 parts by weight of an alkyl ketene dimer as an internal sizing agent were added to 100 parts by weight of the pulp slurry to prepare a paper stock. The stock was made using a long paper machine and then dried with a multi-cylinder dryer. Thereafter, a calendar treatment was performed to obtain a highly permeable support having a basis weight of 150 g / m ² , a thickness of 189 μm, and a Steecht sizing degree of 150 seconds.

<Formation of undercoat layer>
An undercoat layer was formed on the surface of the highly permeable support as follows. That is, first, a slurry having a light calcium carbonate / kaolin / titanium oxide mass ratio of 70/20/10 was prepared as a coating solution used for forming the undercoat layer. Next, with respect to 100 parts by mass of filler (total amount of light calcium carbonate, kaolin, and titanium oxide), 20 parts by mass of a binder having a mass ratio of styrene-butadiene latex / starch of 15/5 is added to obtain a solid content of 60 The composition was prepared so that it might become mass%.

Next, this composition was coated and dried on both surfaces of a highly permeable support with a blade coater so that the dry coating amount was 15 g / m ² per side, and the basis weight was 180 g / m ² , thickness. A 204 μm subbing layer was provided on a highly permeable support.

<Surface treatment to undercoat layer>
A surface treatment liquid was applied to the undercoat layer obtained above. As this surface treatment liquid, a 5 mass% borax aqueous solution heated to 30 ° C. was used, and an air knife coater was used to apply a wet coating amount of 14 g / m ² (the coating amount after drying was 0.7 g / m ² . It was applied at 30 m / min. In addition, when this coating amount is observed visually, it will be in the state which was impregnated without overflowing the surface treatment coating liquid provided at the surface treatment process on the undercoat layer.

<Formation of ink receiving layer>
Immediately after the surface treatment liquid was impregnated in the undercoat layer, an ink receiving layer was formed on the surface coated with the surface treatment liquid. At this time, an ink receiving layer (coating layer) was formed as follows.

  Dispersion was made so that the solid content of alumina hydrate in pure water was 5% by mass, and then hydrochloric acid was added thereto to adjust the pH to 4, followed by stirring for a while. Thereafter, this dispersion was heated to 95 ° C. with stirring, and kept at this temperature for 4 hours. Then, while maintaining this temperature, the pH was adjusted to 10 with caustic soda and stirred for 10 hours. Thereafter, the temperature of the dispersion was returned to room temperature, and the pH was adjusted to 7-8 with hydrochloric acid.

Further, desalting treatment was performed, and then acetic acid was added to peptize to obtain a colloidal sol. When the alumina hydrate obtained by drying this colloidal sol was measured by X-ray diffraction, it showed a boehmite structure (pseudo boehmite). At this time, the BET specific surface area was 138 g / m ² , and the pore volume was 0.75 cm ³ / g. When observed with an electron microscope, it was flat and had an average aspect ratio of 7.4 and an aspect ratio of 0.7.

  The alumina hydrate colloidal sol prepared above was concentrated to prepare a 22.5 mass% dispersion. Next, a 3% by mass boric acid aqueous solution was added to this dispersion so that the boric acid solid content was 0.50 parts by mass in terms of boric acid solid content with respect to 100 parts by mass of the alumina hydrate solid content. A hydrate dispersion was obtained.

Next, polyvinyl alcohol was dissolved in pure water to obtain an aqueous solution having a solid content of 9% by mass. Thereafter, the boric acid-containing alumina hydrate dispersion and the previously prepared polyvinyl alcohol aqueous solution were mixed with an alumina hydrate solid content and a polyvinyl alcohol solid content ratio (mass ratio) of 100: 9 using a static mixer. It mixed so that it might become. The mixed liquid immediately after mixing was used as a coating liquid for the ink receiving layer, and this was applied by a die coater at 30 m / min so that the dry coating amount was 30 g / m ² . Then, this coating liquid was dried at 170 ° C., and an ink receiving layer was provided to obtain a recording medium.

  At this time, the coating width of the die head was applied so as to be narrower in the longitudinal direction and the vertical direction than the highly permeable support on which the surface treatment liquid was applied to the undercoat layer. That is, the porous ink receiving layer does not exist at both ends positioned perpendicular to the longitudinal direction of the recording medium surface. The portion where the porous ink receiving layer is not present is 85 mm from the end of the recording medium at each end. The width in the direction perpendicular to the longitudinal direction of the recording medium is 1060 mm.

<Rewetting liquid application / drying to porous ink receiving layer>
Next, a glossy surface was formed by the following rewet cast method. First, as a coating solution, 0.2 parts by mass of a polyethylene emulsion (trade name: Polymeron 618, manufactured by Chukyo Yushi Co., Ltd.) and 0.2 parts by mass of a surfactant (trade name: Surfynol) with respect to 100 parts by mass of water. 465, manufactured by Nissin Chemical Co., Ltd.) was added to prepare a coating solution. This coating solution was uniformly applied to the entire surface of the ink receiving layer including the end side surface of the highly permeable support of the recording medium to wet the ink receiving layer. Then, with the ink receiving layer in a wet state, the recording medium was pressed against a heated mirror drum (cast drum) under the following conditions, dried and rewet casted to obtain the recording medium of this example.
Rewet casting conditions Coating solution temperature: 60 ° C
Mirror drum (cast drum) temperature: 95 ° C
Nip pressure during pressure contact: 130 kg / cm ²
Time from the start of application to the end of drying: 30 seconds (Example 2)
In Example 1, the part where the porous ink receiving layer is not present is changed so that both ends are 40 mm from the end of the recording medium. A medium was obtained.

(Example 3)
In Example 1, the part in which the porous ink receiving layer is not present is changed except that both ends thereof are 35 mm from the end of the recording medium. A medium was obtained.

Example 4
In Example 1, the part where the porous ink receiving layer is not present is changed except that both ends thereof are 20 mm from the end of the recording medium. A medium was obtained.

(Example 5)
In Example 1, the portion where the porous ink receiving layer is not present is not changed except that both ends are 15 mm from the end of the recording medium. A medium was obtained.

(Example 6)
In Example 1, the portion where the porous ink receiving layer is not present is not changed except that both ends are 10 mm from the end of the recording medium. A medium was obtained.

(Example 7)
In Example 1, an undercoat layer was not provided, and a surface treatment was performed directly on a highly permeable support to form a porous ink receiving layer. The recording medium of this example was obtained without changing except that the porous ink receiving layer was changed to a dry coating amount of 20 g / m ² .

(Example 8)
In Example 7, the recording medium of this example was obtained by setting the portions where the porous ink receiving layer is not present to be 40 mm from both ends of the recording medium.

Example 9
In Example 7, the recording medium of this example was obtained by setting the portions where the porous ink receiving layer was not present to be 35 mm from both ends of the recording medium.

(Example 10)
In Example 7, the recording medium of this example was obtained by setting the portions where the porous ink receiving layer was not present to be 20 mm from both ends of the recording medium.

(Example 11)
In Example 7, the recording medium of this example was obtained by setting the portions where the porous ink receiving layer was not present to be 15 mm from both ends of the recording medium.

Example 12
In Example 7, the recording medium of this example was obtained by setting the portions where the porous ink receiving layer was not present to be 10 mm from both ends of the recording medium.

(Example 13)
In Example 1, the recording medium of this example was obtained without making any changes except that the high-penetrating support was changed so that the steak size of the highly permeable support was changed from 150 seconds to 100 seconds.

(Example 14)
The recording medium of this example was obtained in the same manner as in Example 13, except that the portion where the porous ink receiving layer was not present was changed to 40 mm from the end of the recording medium at both ends.

(Example 15)
The recording medium of this example was obtained in the same manner as in Example 13, except that the portion where the porous ink receiving layer was not present was changed to 35 mm from the edge of the recording medium at both ends.

(Example 16)
The recording medium of this example was obtained in the same manner as in Example 13, except that the portion where the porous ink receiving layer was not present was changed to 20 mm from the end of the recording medium at both ends.

(Example 17)
The recording medium of this example was obtained in the same manner as in Example 13, except that the portion where the porous ink receiving layer was not present was changed to 15 mm from the edge of the recording medium at both ends.

(Example 18)
The recording medium of this example was obtained in the same manner as in Example 13, except that the portion where the porous ink receiving layer was not present was changed to 10 mm from the end of the recording medium at both ends.

(Example 19)
This was carried out in the same manner as in Example 13, and at this time, no undercoat layer was provided, and a surface treatment was performed directly on the highly permeable support to form a porous ink receiving layer. The porous ink receiving layer was changed so that the dry coating amount was 20 g / m ² to obtain the recording medium of this example.

(Example 20)
In Example 19, the recording medium of this example was obtained by setting the portions where the porous ink receiving layer was not present to be 40 mm from both ends of the recording medium.

(Example 21)
In Example 19, the recording medium of this example was obtained by setting the portions where the porous ink receiving layer was not present to be 35 mm from both ends of the recording medium.

(Example 22)
In Example 19, the recording medium of this example was obtained by setting the portions where the porous ink receiving layer was not present to be 20 mm from both ends of the recording medium.

(Example 23)
In Example 19, the part where the porous ink-receiving layer was not present was 15 mm from the end of the recording medium at both ends to obtain the recording medium of this example.

(Example 24)
In Example 19, the part where the porous ink receiving layer was not present was 10 mm from the end of the recording medium at both ends, and the recording medium of this example was obtained.

(Example 25)
The recording medium of this example was obtained in the same manner as in Example 1, except that the high-penetrating support was changed so that the steecht sizing degree was changed from 150 seconds to 30 seconds.

(Example 26)
The recording medium of this example was obtained in the same manner as in Example 25, except that the portion where the porous ink receiving layer was not present was changed to 40 mm from the end of the recording medium at both ends.

(Example 27)
The recording medium of this example was obtained in the same manner as in Example 25, except that the portion where the porous ink receiving layer was not present was changed to 35 mm from the end of the recording medium at both ends.

(Example 28)
The recording medium of this example was obtained in the same manner as in Example 25 except that the portions where the porous ink receiving layer was not present were changed to 20 mm from the end of the recording medium at both ends.

(Example 29)
The recording medium of this example was obtained in the same manner as in Example 25, except that the portion where the porous ink receiving layer was not present was changed to 15 mm from both ends of the recording medium.

(Example 30)
The recording medium of this example was obtained in the same manner as in Example 25, except that the portions where the porous ink receiving layer was not present were changed to 10 mm from the end of the recording medium at both ends.

(Example 31)
This was carried out in the same manner as in Example 25. At this time, an undercoat layer was not provided, and a surface treatment was performed directly on the highly permeable support to form a porous ink receiving layer. The porous ink receiving layer was changed so that the dry coating amount was 20 g / m ² to obtain the recording medium of this example.

(Example 32)
In Example 31, the recording medium of this example was obtained by setting the portions where the porous ink receiving layer was not present to be 40 mm from both ends of the recording medium.

(Example 33)
In Example 31, the recording medium of this example was obtained by setting the portions where the porous ink receiving layer was not present to be 35 mm from both ends of the recording medium.

(Example 34)
In Example 31, the recording medium of this example was obtained by setting the portions where the porous ink receiving layer was not present to be 20 mm from both ends of the recording medium.

(Example 35)
In Example 31, the recording medium of this example was obtained by setting the portions where the porous ink receiving layer was not present at both ends to be 15 mm from the end of the recording medium.

(Example 36)
In Example 31, the recording medium of this example was obtained by setting the portions where the porous ink receiving layer was not present to be 10 mm from both ends of the recording medium.

(Comparative Example 1)
In Example 1, the recording medium of this comparative example was obtained without any change except that the high-penetrating support was changed so that the steecht degree of the support was 150 to 200 seconds.

(Comparative Example 2)
The recording medium of this comparative example was obtained in the same manner as in Comparative Example 1, except that the portion where the porous ink receiving layer was not present was changed to be 40 mm from the end of the recording medium at both ends.

(Comparative Example 3)
The recording medium of this comparative example was obtained in the same manner as in Comparative Example 1, except that the portion where the porous ink receiving layer was not present was changed to 35 mm from the end of the recording medium at both ends.

(Comparative Example 4)
The recording medium of this comparative example was obtained in the same manner as in Comparative Example 1, except that the portion where the porous ink receiving layer was not present was changed to 20 mm from the end of the recording medium at both ends.

(Comparative Example 5)
The recording medium of this comparative example was obtained in the same manner as in Comparative Example 1, except that the portion where the porous ink receiving layer was not present was changed to 15 mm from both ends of the recording medium.

(Comparative Example 6)
The recording medium of this comparative example was obtained in the same manner as in Comparative Example 1, except that the portions where the porous ink receiving layer was not present were changed to 10 mm from both ends of the recording medium.

(Comparative Example 7)
The same procedure as in Comparative Example 1 was carried out. At this time, the undercoat layer was not provided, and a surface treatment was performed directly on the highly permeable support to form a porous ink receiving layer. The porous ink receiving layer was changed so that the dry coating amount was 20 g / m ² to obtain a recording medium of this comparative example.

(Comparative Example 8)
The recording medium of this comparative example was obtained in the same manner as in Comparative Example 7, except that the portion where the porous ink receiving layer was not present was 40 mm from both ends of the recording medium.

(Comparative Example 9)
The recording medium of this comparative example was obtained in the same manner as in Comparative Example 7, except that the portion where the porous ink receiving layer was not present was 35 mm from both ends of the recording medium.

(Comparative Example 10)
The recording medium of this comparative example was obtained in the same manner as in Comparative Example 7, except that the portion where the porous ink receiving layer was not present was 20 mm from both ends of the recording medium.

(Comparative Example 11)
The recording medium of this comparative example was obtained in the same manner as in Comparative Example 7, except that the portions where the porous ink receiving layer was not present were 15 mm from both ends of the recording medium.

(Comparative Example 12)
The recording medium of this comparative example was obtained in the same manner as in Comparative Example 7, except that the portion where the porous ink receiving layer was not present was 10 mm from both ends of the recording medium.

  (Comparative Example 13) Rewet casting was performed in the same manner as in Example 1 except that the removal was performed using a slitter at a position of 95 mm on one side from the end of the recording medium, leaving no uncoated part of the porous ink receiving layer. It was. However, soon after the operation started, sticking occurred at the edge, resulting in a paper break and the operation was stopped.

(Comparative Example 14)
The rewet casting was performed in the same manner as in Example 3 except that the removal was performed using a slitter at a position 40 mm from one end and no uncoated portion of the porous ink receiving layer was left. However, soon after the operation started, sticking occurred at the edge, resulting in a paper break and the operation was stopped.

(Comparative Example 15)
The rewet cast was performed in the same manner as in Example 7 except that the removal was performed using a slitter at a position of 95 mm on one side from the end portion, leaving no uncoated portion of the porous ink receiving layer. However, soon after the operation started, sticking occurred at the edge, resulting in a paper break and the operation was stopped.

(Comparative Example 16)
Rewet casting was performed in the same manner as in Example 8 except that the removal was performed using a slitter at a position 40 mm on one side from the end, leaving no uncoated portion of the porous ink receiving layer. However, soon after the operation started, sticking occurred at the edge, resulting in a paper break and the operation was stopped.

(Comparative Example 17)
The rewet casting was performed in the same manner as in Example 13 except that the removal was performed using a slitter at a position of 95 mm on one side from the end portion, leaving no uncoated portion of the porous ink receiving layer. However, soon after the operation started, sticking occurred at the edge, resulting in a paper break and the operation was stopped.

(Comparative Example 18)
Rewet casting was performed in the same manner as in Example 14 except that the removal was performed using a slitter at a position 40 mm on one side from the end, leaving no uncoated portion of the porous ink receiving layer. However, soon after the operation started, sticking occurred at the edge, resulting in a paper break and the operation was stopped.

(Comparative Example 19)
Rewet casting was performed in the same manner as in Example 19 except that the removal was performed using a slitter at a position of 95 mm on one side from the end, and no uncoated portion of the porous ink receiving layer was left. However, soon after the operation started, sticking occurred at the edge, resulting in a paper break and the operation was stopped.

(Comparative Example 20)
The rewet cast was performed in the same manner as in Example 20 except that the removal was performed using a slitter at a position 40 mm from one end and no uncoated portion of the porous ink receiving layer was left. However, soon after the operation started, sticking occurred at the edge, resulting in a paper break and the operation was stopped.

(Comparative Example 21)
The rewet casting was performed in the same manner as in Example 25 except that the removal was performed using a slitter at a position of 95 mm on one side from the end, and the uncoated portion of the porous ink receiving layer was not left. However, soon after the operation started, sticking occurred at the edge, resulting in a paper break and the operation was stopped.

(Comparative Example 22)
Rewet casting was performed in the same manner as in Example 26 except that the removal was performed using a slitter at a position 40 mm from one end and no uncoated portion of the porous ink receiving layer was left. However, soon after the operation started, sticking occurred at the edge, resulting in a paper break and the operation was stopped.

(Comparative Example 23)
Rewet casting was performed in the same manner as in Example 31 except that the removal was performed using a slitter at a position of 95 mm on one side from the end and no uncoated part of the porous ink receiving layer was left. However, soon after the operation started, sticking occurred at the edge, resulting in a paper break and the operation was stopped.

(Comparative Example 24)
Rewet casting was performed in the same manner as in Example 32 except that the removal was performed using a slitter at a position 40 mm from one end and no uncoated portion of the porous ink receiving layer was left. However, soon after the operation started, sticking occurred at the edge, resulting in a paper break and the operation was stopped. Table 1 shows the evaluation results of the above Examples and Comparative Examples.

It is a figure showing an example of the process of winding up a recording medium in roll shape. (A) is a perspective view showing the process of cutting the edge of the coated paper with a slitter, (B) is a perspective view showing the process of winding the coated paper into a roll, and (C) is a conventional support. It is a side view of a recording medium. It is a figure showing an example of the process of winding up a recording medium in roll shape. (D) is a perspective view showing that an uncoated portion in which a porous ink receiving layer is not present is disposed at both ends positioned in a direction perpendicular to the longitudinal direction of the surface of the recording medium. (E) is a perspective view showing a process of winding a recording medium in a roll shape, and (F) is a side view of the porous ink receiving layer 7. (G) is a side view of the uncoated portion 6. It is a figure showing the process from application | coating of a rewetting liquid to the press-contact of a mirror surface drum (cast drum) using a rewetting cast method. In a recording medium in which a coating layer is provided on a highly permeable support having a Steecht degree of 30 seconds or less, a rewet liquid is applied to the porous ink receiving layer side, and the rewet liquid permeates at that time. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 End side surface which pulp layer exposed 2 Slitter 3 Support body 4 Coating layer 5 Undercoat layer 6 Uncoated part (portion where porous ink receiving layer does not exist)
7 Porous Ink Receiving Layer 8 Auxiliary Roll 9 Rewetting Liquid Application Unit 10 Pressing Roll 11 Mirror Drum (Cast Drum)
12 Take-off roll 13 Recording medium 14 Part where rewetting liquid penetrated into pulp layer 15 Rewetting surface 16 Rewetting liquid

Claims (2)

Applying a coating liquid containing a pigment and a binder on a support to form a porous ink receiving layer;
Applying a rewetting liquid onto the porous ink receiving layer to wet the porous ink receiving layer;
A method for producing a recording medium, comprising the steps of: pressing the wet porous ink-receiving layer against a mirror drum with a pressure roller and drying, followed by peeling off the mirror drum;
The support is a highly permeable support;
When the recording medium is brought into pressure contact with the mirror drum, the porous ink receiving layer is not present at both ends positioned perpendicular to the longitudinal direction of the recording medium surface. Method.   The portions where the porous ink receiving layer is not present at both ends located in the direction perpendicular to the longitudinal direction of the surface of the recording medium are 15 mm or more and 40 mm or less from the end of the recording medium, respectively, at both ends. The method for manufacturing a recording medium according to claim 1.

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