JP2002225421A - Method for manufacturing ink jet image forming material and ink jet image forming material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for efficiently manufacturing an ink jet image forming material having a high quality and a high image quality. SOLUTION: The method for efficiently manufacturing the ink jet image forming material having an ink accepting layer containing thermoplastic resin particles in an outermost layer on a support and an ink solvent absorption layer adjacent to the ink accepting layer comprises the steps of simultaneously coating double layers of the ink accepting layer and the ink solvent absorption layer, then once cooling a coating film temperature to 1 to 15 deg.C, and then drying the accepting layer and the absorption layer at a coating film temperature of <=Tg of the thermoplastic fine particles of the outermost layer and >=10 deg.C or <=MFT and >=10 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an ink jet image forming material (also referred to simply as an image forming material) and an ink jet image forming material, and more particularly to a method for efficiently producing a high quality, high quality ink jet image forming material. And an inkjet image forming material.

[0002]

2. Description of the Related Art An ink jet recording method is capable of recording a high-definition image with a relatively simple apparatus, and is rapidly developing in various fields. 2. Description of the Related Art Printers that employ an ink jet recording method are manufactured in a wide range of fields, and the types of inks and image forming materials are also diversified according to the intended use.

In recent years, there has been developed an image forming method using an ink / image forming material, such as an ink jet printer and an ink / image forming material, for achieving so-called photographic image quality for the purpose of forming images requiring high image quality such as landscape images and portraits. . Ink jet images formed by these image forming methods are very excellent in image quality, and have image quality equal to or higher than that of images formed by conventional image forming methods using silver halide photographic light-sensitive materials.

However, these ink jet image forming methods use a dye ink, and the image storability such as light fastness and bleeding is still far from the storability of an image formed by a silver halide photographic material. Had no shortcomings.

In order to improve the image storability, pigment inks using a pigment having excellent storability as a colorant have been developed.

[0006] However, when an ink-jet image is formed using this pigment ink, although the above-mentioned light fastness and bleeding are excellent, there is a disadvantage that the image quality, abrasion resistance and water resistance are inferior.

On the other hand, in recent years, ink jet image forming materials having a porous layer formed by combining inorganic fine particles such as silica and alumina with a small amount of a water-soluble polymer as a binder have been developed. Since the image forming material has a large void portion inside the layer, the ink is rapidly absorbed into the void portion by capillary action, and a large amount of ink can be held in the void portion inside. , Has the following two features. This provides excellent drying properties,
In addition, since the ink is rapidly absorbed, the dot shape is kept close to a perfect circle, which produces an advantage that the image is excellent in clarity. Further, good gloss can be provided by combining with a waterproof support.

When the above-described pigment ink is combined with the ink-jet image forming material containing the inorganic fine particles and having the porous layer formed thereon, the pigment particles penetrate into the inside because the pore diameter of the pores is smaller than that of the pigment particles. However, since the image cannot be formed and is fixed to the surface of the medium to form an image, the scratch resistance and water resistance of the image are further deteriorated.

In addition, since the surface reflection of the pigment particles is significantly different from that of the unprinted portion where no pigment particles are present, a so-called bronzing phenomenon that produces metallic luster occurs, and the uniformity of the image is such that the gloss varies depending on the image portion. Is greatly impaired, and the image quality is greatly reduced.

In order to solve this drawback, methods for fixing and fixing various pigment particles have been devised. For example, a method has been devised in which another polymer fixing agent is contained in the pigment ink, and the polymer fixes the pigment when the ink lands on the surface of the image forming material. However, it has disadvantages such as greatly impairing the stability of the ink and incomplete fixing, and has not yet been able to eliminate the uniformity of glossiness and bronzing between a printed portion and an unprinted portion.

On the other hand, a method of imparting this pigment fixing function to an image forming material has also been devised. This is to provide a porous layer formed from thermoplastic resin particles on the top of the image forming material, and after printing, heat and pressurize to soften the resin particle layer and fix and fix the pigment particles. Let's do it.

For example, Japanese Patent Application Laid-Open No. 11-192775 discloses that the overlapping ratio between the pore diameter distribution of a porous layer formed of thermoplastic resin particles and the particle diameter distribution of pigment particles in an ink is 0.1 to 10%. % Has been proposed. By setting the distribution of the two to the above ratio, the pigment particles enter the inside of the porous layer appropriately formed of the thermoplastic resin particles, and by heating and pressing in this state, the pigment particles and the resin component Are strongly bonded to each other, and an image having excellent scratch resistance and water resistance can be obtained.

Japanese Patent Application Laid-Open No. 2000-158803 discloses an ink jet ink for pigment inks, wherein an ink receiving layer is provided on a support, and the upper layer is made of thermoplastic resin particles having an average particle diameter of 1 μm or more. A recording sheet has been proposed. By setting the size of the thermoplastic resin particles to 1 μm or more, voids through which the pigment particles in the ink can sufficiently pass are formed. The pigment particles in the ink pass through the pores and exist inside the porous layer formed of the thermoplastic resin particles. It is reported that by performing heating and pressure treatment in this state, water resistance, light resistance and gloss can be simultaneously satisfied.

In each of these methods, the pigment particles in the ink are incorporated into a porous layer formed of thermoplastic resin particles, and then the thermoplastic resin particles are melted and formed by heat and pressure treatment. In order to form a film, an image is formed in a state where the pigment particles are covered with a resin. For this reason,
It has the advantage of greatly improving the disadvantages inherent to pigment inks, such as water resistance, scratch resistance, and bronzing.

However, when an ink-jet image-forming material having an ink receiving layer containing thermoplastic resin particles as an outermost layer on a support and having an ink solvent absorbing layer adjacent to the ink receiving layer is simultaneously coated in multiple layers. In addition, there is often no coagulation on the slide surface or uniform flow down on the slide surface, resulting in an uneven coating layer. In addition, coating failures, often referred to as cissing, often occur, reducing the product yield.

Further, in the drying step, blow-off unevenness, cracks, interfacial mixing and the like occur, and the quality of the coating film may be significantly impaired.

[0017]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for efficiently producing a high quality, high quality ink jet image forming material.

[0018]

The above object of the present invention has been attained by the following constitutions.

1. In a method for producing an inkjet image-forming material having an ink receiving layer containing thermoplastic resin particles as an outermost layer on a support and having an ink solvent absorbing layer adjacent to the ink receiving layer, the ink receiving layer and the ink solvent After the simultaneous coating of the absorbing layer and the coating temperature is once cooled to 1 to 15 ° C, the coating is dried at a temperature range of 10 ° C or higher and Tg or lower of the thermoplastic fine particles of the outermost layer or MFT or lower. A method for producing an ink-jet image forming material.

2. The physical properties of the outermost coating solution on the support at a coating solution temperature of 15 ° C. during simultaneous multilayer coating are 100 to 200.
2. The method for producing an ink-jet image forming material according to the above 1, wherein a coating liquid having a pressure of 0 mPa · s is used.

3. 2. The method for producing an ink-jet image forming material according to the above item 1, wherein the time until the completion of the drying is determined by the numerical value represented by the equation (1).

4. Wet bulb temperature 5 to 40 ° C, membrane surface temperature 10
2. The method for producing an ink-jet image forming material according to the above 1, wherein the coating film is dried by blowing hot air at 50 ° C.

5. 2. The method for producing an ink jet image forming material according to the above 1, wherein the temperature of the coating solution is 30 ° C. or higher and Tg of the thermoplastic resin fine particles or lower.

6. 2. The method for producing an ink-jet image forming material according to the above item 1, wherein the cooling is performed by a horizontal set method immediately after the application.

[7] 7. The ink solvent-absorbing layer of the inkjet image-forming material produced by the production method according to any one of 1 to 6, wherein the ink solvent-absorbing layer has a porous structure,
An ink jet image forming material comprising at least one kind of inorganic fine particles selected from at least one kind of colloidal silica, hydrated alumina, and vapor phase alumina.

8. 7. The thermoplastic resin fine particles of the inkjet image-forming material produced by the production method according to any one of 1 to 6, wherein the thermoplastic resin fine particles are vinyl chloride, styrene, acrylic, urethane, polyester, ethylene, and vinyl chloride. Characterized in that it is at least one type of latex particles selected from vinyl acetate-based, vinyl chloride-vinylidene chloride-based, vinyl chloride-acrylic-based, vinylidene chloride-acrylic-based, styrene-butadiene-based, and styrene-acrylic-based materials. Ink jet image forming materials.

9. Tg and MF of thermoplastic resin fine particles
9. The ink-jet image forming material as described in 8 above, wherein T is 40 to 100 ° C.

The present invention will be described in more detail. The ink jet image forming material of the present invention has an ink receiving layer containing thermoplastic resin particles as an outermost layer on a support, and has an ink solvent absorbing layer adjacent to the ink receiving layer. And
After the ink receiving layer and the ink solvent absorbing layer are simultaneously multi-layer coated, after once cooling the coating temperature to 1 to 15 ° C.,
It is manufactured by drying the coating at a temperature of 10 ° C. or more and at a temperature of Tg (glass transition point) of thermoplastic fine particles of the outermost layer or less or MFT (minimum film forming temperature) or less. in this case,
All other hydrophilic binder layers need only be applied once, and simultaneous application is preferred.

As a coating method, a curtain coating method or a method disclosed in US Pat. No. 2,761,419 or US Pat.
A slide bead coating method using a hopper and an extrusion coating method using a hopper described in Japanese Patent No. 1,791 are preferably used.

In this simultaneous multi-layer coating, the temperature of the coating solution is 15 ° C.
Physical properties of the coating liquid of the uppermost layer are 100 to 2000 mPa
By being s, interfacial mixing of both layers is prevented. In particular, the physical properties of the coating liquid of the uppermost layer are 200 to 1000 mPa.
s, the physical properties of the coating liquid in the other layers are preferably 3000 mPa · s or more. At this time, the thickness of the uppermost coating liquid is preferably 25 μm or less.

The ink-jet image forming material of the present invention comprises
It is characterized in that a porous layer comprising voids having an ink solvent retaining ability is formed, and the porous layer is formed mainly by soft aggregation of a hydrophilic binder and inorganic fine particles.

Conventionally, various methods for forming voids in a film are known. For example, a uniform coating solution containing two or more polymers is applied on a support, and these polymers are dried in a drying process. A method for forming voids by phase separation from each other, a coating solution containing solid fine particles, a hydrophilic or hydrophobic binder is coated on a support, and after drying, the inkjet image forming material contains water or a suitable organic solvent. A method of forming voids by dissolving solid fine particles by immersing in a liquid, after applying a coating solution containing a compound that has the property of foaming during film formation, foaming this compound in the drying process to form voids in the film Method, a method of applying a coating solution containing porous solid fine particles and a hydrophilic binder on a support, and forming voids in the porous fine particles and between the fine particles, for the hydrophilic binder Solid microparticles having a volume equal to or more than an equal amount (preferably 1.0 times or more) and / or a coating solution containing oil droplets of fine particles and a hydrophilic binder are applied on a support to form voids between the solid microparticles. Although a method and the like are known, in the present invention, an average particle size of 10
It is preferably formed by incorporating various inorganic solid fine particles of 0 nm or less.

Examples of the inorganic fine particles used for the above purpose include fumed silica, colloidal silica, alumina hydrate, fumed alumina, light calcium carbonate, heavy calcium carbonate, magnesium carbonate, kaolin, clay , Talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc hydroxide, zinc sulfide, zinc carbonate, hydrotalcite, aluminum silicate, diatomaceous earth, calcium silicate, magnesium silicate, synthetic amorphous silica,
Examples include white inorganic pigments such as alumina, colloidal alumina, pseudoboehmite, aluminum hydroxide, lithopone, zeolite, and magnesium hydroxide. In particular,
Preference is given to fumed silica, colloidal silica, hydrated alumina and fumed alumina.

The average particle diameter of the inorganic fine particles (hereinafter, also simply referred to as fine particles) is determined by observing the particles themselves or the particles that appear on the cross section or surface of the void layer with an electron microscope,
The particle size of zero arbitrary particles is obtained, and is obtained as a simple average value (number average). Here, the particle size of each particle is
It is represented by a diameter assuming a circle equal to the projected area.

From the viewpoint of obtaining a high-density image, clear image and low-cost production, it is preferable to use solid fine particles selected from silica, alumina or alumina hydrate as the solid fine particles. preferable.

As the silica, for example, silica or colloidal silica synthesized by an ordinary wet method or silica synthesized by a gas phase method is preferably used. As the fine particle silica particularly preferably used in the present invention, colloidal silica is preferably used. Silica or fine-particle silica synthesized by a gas phase method is preferable.Particularly, fine-particle silica synthesized by a gas phase method has a high porosity and is added to a cationic polymer used for the purpose of immobilizing a dye. This is preferable because sometimes a coarse aggregate is hardly formed. Alumina or alumina hydrate may be crystalline or amorphous, and may have any shape such as irregular particles, spherical particles, and acicular particles.

The fine particles of the present invention are preferably in a state where the fine particle dispersion before mixing with the cationic polymer is dispersed to primary particles.

In order to obtain the effects of the present invention, the inorganic fine particles on the support preferably have a particle size of 100 nm or less. For example, in the case of the above-mentioned fumed silica, the average particle diameter of the primary particles of the inorganic fine particles dispersed in the state of the primary particles (the particle diameter in a dispersion state before coating) is preferably 100 nm or less, It is more preferably 4 to 50 nm, most preferably 4 to 20 nm.

As the most preferably used silica synthesized by a gas phase method having an average primary particle diameter of 4 to 20 nm, for example, Aerosil manufactured by Nippon Aerosil Co., Ltd. is commercially available. The vapor-phase-process fine-particle silica can be relatively easily dispersed into primary particles by easily sucking and dispersing in water using, for example, a jet stream inductor mixer manufactured by Mitamura Riken Kogyo KK.

The hydrophilic binder preferably used in the present invention includes, for example, polyvinyl alcohol, gelatin, polyethylene oxide, polyvinyl pyrrolidone,
Polyacrylic acid, polyacrylamide, polyurethane,
Dextran, dextrin, carrageenan (κ,
ι, λ, etc.), agar, pullulan, water-soluble polyvinyl butyral, hydroxyethyl cellulose, carboxymethyl cellulose and the like. Two or more of these water-soluble resins can be used in combination.

The water-soluble resin more preferably used in the present invention is polyvinyl alcohol. The polyvinyl alcohol is not only ordinary polyvinyl alcohol obtained by hydrolyzing polyvinyl acetate, but also modified polyvinyl alcohol such as polyvinyl alcohol having a cation-modified terminal or anion-modified polyvinyl alcohol having an anionic group.

The polyvinyl alcohol obtained by hydrolyzing vinyl acetate preferably has an average degree of polymerization of 1,000 or more, and particularly preferably has an average degree of polymerization of 1,500 to 5,
000 are preferably used.

The saponification degree is preferably from 70 to 100%, particularly preferably from 80 to 99.5%.

As the cation-modified polyvinyl alcohol, for example, a primary or tertiary amino group or a quaternary ammonium group as described in JP-A-61-10483 can be used as a main chain or a side chain of the polyvinyl alcohol. Polyvinyl alcohol contained therein, which is obtained by saponifying a copolymer of an ethylenically unsaturated monomer having a cationic group and vinyl acetate.

Examples of the ethylenically unsaturated monomer having a cationic group include trimethyl- (2-acrylamido-2,2-dimethylethyl) ammonium chloride and trimethyl- (3-acrylamido-3,3-dimethylpropyl). Ammonium chloride, N-vinylimidazole, N-vinyl-2-methylimidazole, N
-(3-dimethylaminopropyl) methacrylamide,
Hydroxylethyltrimethylammonium chloride, trimethyl- (2-methacrylamidopropyl) ammonium chloride, N- (1,1-dimethyl-3-
Dimethylaminopropyl) acrylamide and the like.

The ratio of the monomer having a cation-modified group in the cation-modified polyvinyl alcohol is usually 0.1 to 10 mol%, preferably 0.2 to 5 mol%, based on vinyl acetate.

The anion-modified polyvinyl alcohol is, for example, a polyvinyl alcohol having an anionic group as described in JP-A-1-206088, JP-A-61-237681 and JP-A-63-30797.
No. 9, copolymers of vinyl alcohol and a vinyl compound having a water-soluble group.
265, a modified polyvinyl alcohol having a water-soluble group.

Examples of the nonion-modified polyvinyl alcohol include polyvinyl alcohol derivatives described in JP-A-7-9758, in which a polyalkylene oxide group is added to a part of vinyl alcohol, and JP-A-8-25795. And a block copolymer of a vinyl compound having a hydrophobic group and vinyl alcohol described in Japanese Patent Application Laid-Open Publication No. H11-157,086.

Two or more kinds of polyvinyl alcohols having different degrees of polymerization and different types of modification can be used in combination.

The amount of the inorganic fine particles used in the ink solvent holding layer greatly depends on the required ink absorption capacity, the porosity of the void layer, the type of the inorganic fine particles, and the type of the water-soluble resin. material 1m ² per, usually 5 to
30 g, preferably 10 to 25 g.

The ratio of the inorganic fine particles used for holding the ink solvent to the water-soluble resin is usually 2: 1 to 20:
1, particularly preferably 3: 1 to 10: 1.

The cationic water-soluble polymer having a quaternary ammonium base in the molecule is usually 0.1 to 10 g, preferably 0.1 to 10 g, per m ^{2 of the} ink jet image forming material.
It is used in the range of 2 to 5 g.

The ink-jet image forming material of the present invention comprises
The water-soluble resin is preferably hardened with a hardener in order to obtain excellent gloss and high porosity without deteriorating the brittleness of the film.

The hardener is generally a compound having a group capable of reacting with the water-soluble resin or a compound which promotes the reaction between different groups of the water-soluble resin. It is appropriately selected and used depending on the situation.

Specific examples of hardeners include, for example, epoxy hardeners (diglycidyl ethyl ether, ethylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-diglycidyl cyclohexane, N , N-diglycidyl-4-glycidyloxyaniline, sorbitol polyglycidyl ether, glycerol polyglycidyl ether, etc., aldehyde hardeners (formaldehyde, glyoxal, etc.), active halogen hardeners (2,4-dichloro-4-) Hydroxy-1,3,5-s-triazine, etc.), active vinyl compounds (1,3,5-trisacryloyl-hexahydro-)
s-triazine, bisvinylsulfonyl methyl ether, etc.), boric acid and its salts, borax, aluminum alum and the like.

When polyvinyl alcohol and / or cation-modified polyvinyl alcohol is used as a particularly preferred water-soluble resin, it is preferable to use a hardener selected from boric acid and salts thereof or an epoxy hardener.

Most preferred is a hardener selected from boric acid and its salts. In the present invention, the boric acid or a salt thereof refers to an oxyacid having a boron atom as a central atom and a salt thereof.Specifically, orthoboric acid, diboric acid, metaboric acid, tetraboric acid, pentaboric acid, octanoic acid and These salts are included.

The amount of the hardener used depends on the type of the water-soluble resin,
It varies depending on the type of hardener, the type of inorganic fine particles, the ratio to the water-soluble resin, and the like.
５００500 mg, preferably 10-300 mg.

The above-mentioned hardener may be added to the water-soluble coating solution for holding and forming the ink solvent, or may be added to the coating solution containing the hardening agent. A water-soluble coating liquid for holding and forming an ink solvent may be applied on the body. In addition, after applying and drying a water-soluble coating solution for holding and forming an ink solvent (containing no hardener), the hardener solution can be supplied by overcoating or the like.
Among these, from the viewpoint of production efficiency, a method in which a hardener is added to a water-soluble coating solution for holding and forming an ink solvent and coating is preferably performed.

The ink-jet image forming material of the present invention comprises
For the purpose of improving the water resistance of the obtained image, a cationic polymer may be added. The cationic polymer to be used can be used without any particular limitation. Particularly preferred ones have a weight average molecular weight of 2,000 to 100,0.
00.

The cationic polymer is preferably a polymer having a quaternary ammonium base, and particularly preferably a homopolymer of a monomer having a quaternary ammonium base or another copolymerizable monomer or monomers. Is a copolymer of

In the void layer, the total amount of voids (void volume)
Is preferably 20 ml or more per m ² of the image forming material. When the void volume is less than 20 ml / m ² , when the ink amount at the time of printing is small, the ink absorbency is good, but when the ink amount is large, the ink is not completely absorbed and the image quality is reduced, Problems such as delay in drying are likely to occur.

The upper limit of the void volume is not particularly limited, but it is preferable that the thickness of the void layer is usually 70 μm or less so as not to deteriorate physical properties of the film such as cracks.

In the void layer having an ink retaining ability, the void volume relative to the solid content volume is called a void ratio. In the present invention, it is preferable to set the porosity to 50% or more because the void can be efficiently formed without unnecessarily increasing the film thickness.

In the ink-jet image forming material of the present invention, an ink receiving layer comprising thermoplastic resin particles is provided on a porous layer comprising voids having an ink solvent retaining ability by the soft aggregation of the hydrophilic binder and inorganic fine particles. Is formed.

In the present invention, it is preferable to add various known surfactants to the ink receiving layer, particularly to the outermost layer.
As the surfactant, it is preferable to add at least one kind of fluorine-based surfactant and at least one kind of other surfactant.

The thermoplastic resin particles of the present invention include vinyl chloride, styrene, acrylic, urethane, polyester, ethylene, vinyl chloride-vinyl acetate, and the like.
Latex particles of vinyl chloride-vinylidene chloride type, vinyl chloride-acrylic type, vinylidene chloride-acrylic type, styrene-butadiene type, and styrene-acrylic type can be exemplified.

Points to be considered when selecting a thermoplastic resin include, for example, ink receptivity, gloss after fixing by heating and pressing, and image fastness. Regarding the ink receptivity, when the thermoplastic resin particles are small, the separation between the pigment particles in the pigment ink and the ink solvent becomes slow, which causes a substantial reduction in the absorption rate.

On the other hand, if it is too large, it is not preferable from the viewpoint of adhesiveness to an adjacent solvent absorbing layer when coating on a support and film strength after coating and drying. For this purpose, the preferred thermoplastic resin particle diameter is in the range of 0.05 to 10 μm, more preferably 0.1 to 5 μm.

The criteria for selecting the thermoplastic resin particles include the glass transition point Tg. If the Tg is extremely low, for example, the coating and drying temperature at the time of the production of the recording material is already higher than the Tg, and voids due to the thermoplastic resin particles through which the ink solvent permeates disappear. Further, when Tg is extremely high, a fixing operation at a high temperature is required to form a melt film after inkjet recording with a pigment ink, and there are problems such as load on the apparatus and thermal stability of the support. The preferred Tg of the thermoplastic resin particles is 50 to 150 ° C.
It is.

After the image is formed, it is necessary to suppress the deterioration of the image quality of the recorded image due to its storage with time as much as possible. When using pigment ink, there is no need to worry about density reduction or discoloration in a relatively short period of time as with dye ink, but from the viewpoint of minimizing discoloration of unprinted areas, the above types of thermoplastics It is necessary to select resin particles.

Further, in the present invention, when an image is recorded using an image forming material on which a layer containing a thermoplastic resin is formed, the image forming material is heated and pressurized after the image recording, and the thermoplastic resin layer is formed. Is preferably densified.

The means for heating and pressurizing is not particularly limited, but various methods such as a method of blowing hot air, a method of heating with infrared rays, a method of using a heating and pressurizing roller, a method of pressing on a heating plate, and the like can be used. Method. Here, a method using a heating and pressure roller is preferable from the object of the present invention because the surface state can be most uniformly smoothed, so that the glossiness is easily improved and the graininess is improved. The reason why the heating and pressurization leads to an improvement in graininess is unknown, but as described above, it is presumed that the effects of the present invention are most likely to be exerted by the effects of both heating and pressurization.

In the present invention, the absolute value of one or both of lightness and chroma increases before and after the heat and pressure treatment of the image forming material, and as a result, the color reproduction range is expanded. The magnitude of the color reproduction range can be discussed by, for example, measuring the lightness and saturation of each color of the recorded image before and after the heating and pressurizing processes, and comparing the values before and after the heating and pressurizing processes. For example, among the values of CIELAB-Lab, the value of L ^* can be used as lightness, and the values of a ^* and b ^* can be used as saturation. In order to expand the color gamut, it is necessary that the absolute values of these values increase before and after heating and pressing.

Generally, using these brightness and saturation,
When discussing the size of the color reproduction range, a value ΔE is used. In the present invention, the sum of the ΔE values of the yellow, magenta, cyan, blue, green, and red colors represented by the following equation 1 is 1
It is preferably 0 or more, and more preferably in the range of 15 to 50.

Equation 1: ΔE = ((L ^* _A− L ^* _B ) ² + (a ^* _A)
−a ^* _B ) ² + (b ^* _A− b ^* _B ) ² ) ^1/2 − ((L ^* _WA−
L ^* _WB ) ² + (a ^* _WA− a ^* _WB ) ² + (b ^* _WA− b ^* _WB ) ² )
^1/2 where L ^* _B , a ^* _B , and b ^* _B represent the L ^* value, a ^* value, and b ^* value before heating and pressing, respectively, and L ^* _A , a ^* _A , and b ^* _A are The L ^* value, a ^* value, and b ^* value after heating and pressurization, respectively, are shown.
Here, as the L ^* value, the a ^* value, and the b ^* value, values of solid images of yellow, magenta, cyan, blue, green, and red are used.

For each of the yellow, magenta and cyan colors,
The measurement was performed on patches that output 100% of each of the yellow, magenta, and cyan color inks. For each of the blue, green, and red colors, a 1: 1 mixed color of magenta and cyan, a 1: 1 mixed color of yellow and cyan, and yellow and magenta were used, respectively. 100% of 1: 1 mixed color
Measure the output patch.

Further, L ^* _WB , a ^* _WB , and b ^* _WB are L in the unprinted portion (white portion) before heating and pressing, respectively.
^* Value, a ^* value represents the b ^* value, L ^* _WA, a ^* _WA, b ^* _WA is in an unprinted portion (white portion), respectively heating and after pressing the L ^* value, a ^* value, b ^* Represents a value.

In the equation 1, ((L ^* _A− L ^* _B ) ² + (a ^* _A)
−a ^* _B ) ² + (b ^* _A− b ^* _B ) ² ) ^1/2 represents a change in chromaticity of the colored portion, and ((L ^* _WA− L ^* _WB ) ² + (a ^* _WA− a ^* _WB ) ² +
_{^{(B * W A -b * WB}} ) 2) 1/2 represents the change in chromaticity of the background portion. In an image forming material, the medium itself may be colored by heating and pressurizing, and in order to cancel the effect, in the definition of ΔE in the present invention, a change in chromaticity of a background portion is subtracted.

When ΔE is less than 10, the improvement of the graininess is too small to exert the effect of the present invention, and when ΔE is 15 or more, particularly preferable graininess is provided. On the other hand, if ΔE exceeds 50, the color differs from the originally intended color, and the image quality deteriorates, which is not preferable.

The support used in the present invention includes a support conventionally used for an ink-jet image forming material,
For example, a paper support such as plain paper, art paper, coated paper and cast coated paper, a plastic support, a paper support coated on both sides with a polyolefin, and a composite support in which these are laminated can be used.

For the purpose of increasing the adhesive strength between the support and the void layer, it is preferable to subject the support to a corona discharge treatment or a subbing treatment prior to the application of the void layer. Further, the image forming material of the present invention is not necessarily colorless, and may be a colored image forming material.

In the ink jet image forming material of the present invention, it is preferable to use a paper support in which both sides of the base paper support are laminated with polyethylene, since the recorded image is close to the photographic quality, and a high quality image can be obtained at low cost. Particularly preferred. Such a paper support laminated with polyethylene is described below.

The base paper used for the paper support is made of wood pulp as a main material, and if necessary, in addition to wood pulp, using synthetic pulp such as polypropylene or synthetic fiber such as nylon or polyester. As wood pulp, LBKP, LBSP, NBKP, NBSP, LD
Any of P, NDP, LUKP, and NUKP can be used, but LBKP, NBSP, and LBS containing a large amount of short fibers
It is preferable to use more P, NDP, and LDP.
However, the ratio of LBSP and / or LDP is usually preferably 10% by mass or more and 70% by mass or less.

As the pulp, a chemical pulp containing less impurities (sulfate pulp or sulfite pulp) is preferably used, and pulp having improved whiteness by performing a bleaching treatment is also useful.

In the base paper, sizing agents such as higher fatty acids and alkyl ketene dimers, white pigments such as calcium carbonate, talc and titanium oxide, paper strength agents such as starch, polyacrylamide and polyvinyl alcohol, fluorescent whitening agents, Water retention agents such as polyethylene glycols, dispersants, and softening agents such as quaternary ammonium can be appropriately added.

The freeness of pulp used for papermaking is determined by CSF
The fiber length after beating is preferably 30 to 70% when the sum of the mass% of the remaining 24 mesh and the mass% of the remaining 42 mesh specified in JIS-P-8207 is 30 to 70%. preferable. In addition, it is preferable that the mass% of 4 mesh residue is 20 mass% or less.

The basis weight of the base paper is preferably 30 to 250 g, particularly preferably 50 to 200 g. Base paper thickness is 40
２５０250 μm is preferred.

The base paper may be calendered at the papermaking stage or after the papermaking to provide high smoothness. The base paper density is generally 0.7 to 1.2 g / m ² (JIS-P-8118). Further, the rigidity of the base paper is preferably from 20 to 200 g under the conditions specified in JIS-P-8143.

A surface sizing agent may be applied to the surface of the base paper. As the surface sizing agent, the same sizing agent as that which can be added to the base paper can be used.

The pH of the base paper is preferably 5 to 9 as measured by the hot water extraction method specified in JIS-P-8113.

The polyethylene for covering the front and back surfaces of the base paper is mainly low-density polyethylene (LDPE) and / or high-density polyethylene (HDPE), but other LLDPE, polypropylene and the like can be partially used.

In particular, the polyethylene layer on the side of the void layer is preferably a layer obtained by adding rutile or anatase type titanium oxide to polyethylene to improve opacity and whiteness as widely used in photographic printing paper. The content of titanium oxide is usually from 3 to 20% by mass, and preferably from 4 to 13% by mass, based on polyethylene.

The polyethylene-coated paper may be used as a glossy paper, or may be subjected to a so-called embossing process when the polyethylene is melt-extruded onto the base paper surface to perform a coating process. Those having a surface can also be used in the present invention.

The amount of polyethylene used on the front and back of the base paper is selected so as to optimize the curl under low and high humidity conditions after the provision of the void layer and the back layer. ４０40 μm, 10-30 on the back layer side
It is in the range of μm.

Further, the polyethylene-coated paper support preferably has the following characteristics.

1. Tensile strength: JIS-P-8113
2-30 kg in the vertical direction and 1 in the horizontal direction with the strength specified by
1. It is preferably 20 kg. The tear strength is 10 to 200 g in the vertical direction and 20 to 200 g in the horizontal direction according to the method specified in JIS-P-8116.
Is preferred. Compression modulus ≧ 98.1 MPa 4. Surface Beck smoothness: 20 seconds or more is preferable as a glossy surface under the conditions specified in JIS-P-8119, but may be less than this for so-called molded products. Surface roughness: Surface roughness specified in JIS-B-0601, maximum height 10 μm per reference length 2.5 mm
It is preferably the following. 6. Opacity: 80% or more, particularly preferably 85 to 98%, as measured by the method specified in JIS-P-8138. Whiteness: L ^* defined by JIS-Z-8729,
a ^* and b ^* are L ^* = 80 to 95, a ^* = − 3 to +5, b ^* =
It is preferably −6 to +2. Surface glossiness: 6 specified in JIS-Z-8741
8. It is preferable that the 0 degree specular gloss is 10 to 95%. Clark stiffness: support Clark stiffness in the carrying direction is 50~300cm ^2/100 of the image forming material is preferably 10. Water content of the middle paper: usually 2 to 100% by mass, preferably 2 to 6% by mass with respect to the middle paper.

[0098]

[Embodiment 1] Preparation of image forming material (Preparation of polyethylene coated paper support) Water content 6.5%
A low-density polyethylene having a density of 0.92 and a thickness of 30 μm was applied to the back side of a photographic base paper having a basis weight of 170 g / m ² by a melt extrusion coating method. Then, the density containing 5.5% of anatase-type titanium oxide on the surface side is 0.1%.
92 low-density polyethylene was applied by a melt extrusion coating method at a thickness of 35 μm to prepare a support having both surfaces coated with polyethylene. Furthermore, the surface is subjected to corona discharge treatment,
Immediately thereafter, a support having a gelatin subbing layer of 0.05 g / m ² was prepared by coating with a wire bar.

(Preparation of Titanium Oxide Dispersion) 20 kg of titanium oxide having an average particle diameter of about 0.25 μm (Ishihara Sangyo: W-1)
0) with 150% sodium tripolyphosphate at pH 7.5
g, polyvinyl alcohol (Kuraray Co., Ltd .: PVA2
35, average polymerization degree 3500) 500 g, cationic polymer 150 g and Sannopco Co., Ltd. antifoamer SN38
1 was added to 90 liters of an aqueous solution containing 10 g, and dispersed with a high-pressure homogenizer (manufactured by Sanwa Kogyo Co., Ltd.), and the total amount was finished to 100 liters to obtain a uniform titanium oxide dispersion.

(Preparation of Silica Dispersion-1) 125 kg of fumed silica (Nippon Aerosil Co., Ltd .: A300) having an average primary particle size of about 0.007 μm was jet-streamed by Mitamura Riken Kogyo Co., Ltd. Using an inductor mixer TDS, the mixture was suction-dispersed at room temperature into 620 liters of pure water adjusted to pH = 2.5 with nitric acid, and then the total amount was made up to 694 liters with pure water. Electron micrographs of the particles obtained by diluting this dispersion were taken, and it was confirmed that most of the particles had a size of 0.01 μm or less and were dispersed to primary particles.

(Preparation of Silica Dispersion-2) 25 to 30 parts of a solution (pH = 2.3) containing 1.41 kg of a cationic polymer and 4.2 liters of ethanol was added to 18 liters.
In a temperature range of 6 ° C., 69.4 liters of silica dispersion-1 were added with stirring over 20 minutes, and then boric acid 260
g and an aqueous solution containing 230 g of borax (pH = 7.3)
7.0 liters were added over about 10 minutes, and 1 g of the antifoaming agent SN381 was added. This mixed solution was subjected to pressure of 24.5 MPa with a high pressure homogenizer manufactured by Sanwa Kogyo Co., Ltd.
The mixture was dispersed once and the total amount was made up to 97 liters with pure water to prepare an almost transparent silica dispersion liquid-2.

(Preparation of Fluorescent Whitening Agent Dispersion) 400 g of oil-soluble fluorescent whitening agent UIVITEX-OB manufactured by Ciba-Geigy Co., Ltd., 9000 g of diisodecyl phthalate and 12 liters of ethyl acetate were heated and dissolved. The cationic polymer, saponin 50
The mixture was added to 65 liters of an aqueous solution containing 6000 ml of an aqueous solution and emulsified and dispersed three times with a high-pressure homogenizer manufactured by Sanwa Kogyo Co., Ltd. at a pressure of 24.5 Mpa. Was.
The pH of this dispersion was about 5.3.

(Preparation of Coating Solution) Coating solutions for the first layer, the second layer, the third layer-1, and the fourth layer-1 were prepared in the following procedure.

First Layer Coating Liquid The following additives were sequentially mixed with 600 ml of the silica dispersion liquid 2 at 40 ° C. while stirring.

(1) 194.6 ml of 7% aqueous solution of polyvinyl alcohol (Kuraray Industries, Ltd .: PVA235) (average degree of polymerization: 3500) (2) 25 ml of fluorescent brightener dispersion liquid (3) 33 ml of titanium oxide dispersion liquid ( 4) Daiichi Kogyo Co., Ltd .: 18 ml of latex emulsion AE-803 (5) Make up to 1000 ml with pure water.

The pH of the coating solution was about 4.4, the viscosity at 40 ° C. was 35 mPa · s, and the viscosity of the coating solution at 15 ° C. was about 10,000
mPa · s. A B-type viscometer was used for viscosity measurement.

Second Layer Coating Solution The following additives were sequentially mixed with 650 ml of the silica dispersion liquid 2 at 40 ° C. while stirring.

(1) 71.6% solution of polyvinyl alcohol (manufactured by Kuraray Industries Co., Ltd .: PVA235) (average degree of polymerization: 3500) 201.6 ml (2) Fluorescent brightener dispersion liquid 35 ml (3) Make up to 1000 ml with pure water Finish.

The coating solution pH was about 4.4, the viscosity at 40 ° C. was 40 mPa · s, and the coating solution viscosity at 15 ° C. was about 25,000.
mPa · s.

Third Layer-1 Coating Solution The following additives were sequentially mixed with 650 ml of the silica dispersion liquid 2 at 40 ° C. while stirring.

(1) 201.6 ml of a 7% aqueous solution of polyvinyl alcohol (PVA235 manufactured by Kuraray Industries, Ltd.) (average degree of polymerization: 3500) (2) Silicon dispersion (BY-22 manufactured by Dow Corning Toray Silicone Co., Ltd.) -839) 15 ml (3) Make up to 1000 ml with pure water.

The pH of the coating solution is about 4.5, the viscosity at 40 ° C. is 40 mPa · s, and the viscosity of the coating solution at 15 ° C. is about 2500
It was 0 mPa · s.

Fourth layer-1 Coating liquid (layer containing thermoplastic fine particles) (1) Styrene-acrylic acid copolymer latex 600 ml (particle size 0.3 μm, Tg 50 ° C., MFT 50 ° C.) solid content 50% (w / v) (2) 71.4% aqueous solution of polyvinyl alcohol (Kuraray Industries Co., Ltd .: PVA235) (average degree of polymerization 3500) 171.4 ml (3) 50% aqueous solution of saponin 40 ml (4) After adjusting the pH to 4.5 with nitric acid, pure water Finish the total volume to 1000 ml with. The viscosity of the coating solution at 40 ° C. was 70 mPa · s, and the viscosity of the coating solution at 15 ° C. was 230 mPa · s. The coating solution obtained as described above was filtered by the following filter. First and second layers: TCP10 manufactured by Toyo Roshi Kaisha, Ltd.
3rd layer-1 and 4th layer-1: TCP30 manufactured by Toyo Roshi Kaisha, Ltd., two steps. First on polyethylene coated paper support
Layer (50 μm), second layer (100 μm), third layer-1
(50 μm) and the fourth layer-1 (15 μm). The values in parentheses indicate the wet film thickness, respectively.
The first to fourth layers were simultaneously coated at a coating speed of 150 m / min.

Each coating solution was applied at 40 ° C. using a four-layer slide hopper. Immediately after the application, the coating solution was cooled for 10 seconds in a cooling zone maintained at 6 ° C., and then the coating film was sprayed with hot air. Drying was performed. 3 depending on the water content of the coating
The coating film was dried by changing the temperature and humidity conditions of the blowing hot air for drying at each stage. Initially, under common conditions (drying conditions-
1) Drying was performed by blowing hot air at 25 ° C. and 15% relative humidity until the water content of the coating film reached 200% (coating temperature at this time: 12 ° C.). The sample was completely dried by changing the temperature and humidity conditions of the hot air as shown in FIG. The coating was completely dried within 4 minutes of application under all drying conditions. After the drying was completed, the sample was conditioned in an atmosphere of 20 to 25 ° C and a relative humidity of 40 to 60% for 2 minutes to wind up the sample to obtain an image forming material having a porous coating film. The visual state of the coating film after drying and the ink absorbency by printing were evaluated by the following methods, and the results are shown in Table 1.

Drying conditions Drying conditions-1 Immediately after coating to a water content of 200%: 25% common, 15% relative humidity (12 ° C wet bulb temperature) Drying conditions-2 Water content of 200% to 50%: Coating temperature Is almost the same as the wet bulb temperature. Drying condition-3 From 50% moisture content to complete drying:
The coating temperature rises from the wet bulb temperature to almost the same as the drying air temperature as the water content decreases.

Coating State After the unprinted image forming material is pressed by a hot roll heated to 110 ° C. to perform the densification treatment of the thermoplastic organic fine particles, the occurrence of cracks and the surface gloss of the coating film on the surface are determined. It was visually evaluated. ◎ No cracks and good gloss ○ Slight cracks but good gloss △ Good cracks but good gloss × Many cracks and poor gloss Ink absorption Seiko Epson Corporation It was discharged onto the surface of the image forming material by using a color inkjet printer PM-700C made by KK. Here, as an output image, high-definition color digital standard image data “N5
・ Bicycle ”(issued in December 1995) was used. Further, after the recording, the thermoplastic organic fine particles were densified by pressing with a hot roll heated to 110 ° C.良好 A good image was obtained. × There were places where ink overflow occurred.

[0117]

[Table 1]

As is clear from Table 1, under the drying conditions of the present invention, both the state of the coating film and the ink absorbency are superior to those of the comparative example.

Example 2 A first layer, a second layer and a third layer-1 were prepared and filtered under the same conditions as in Example 1. For the fourth layer, the viscosity of the coating solution was adjusted by changing the amount of the aqueous PVA solution added to the coating solution, and filtration was performed (fourth layer-1, 2, 3, 4). First layer (50 μm), second layer (100 μm), third layer-1 (50 μm), fourth layer-1 on polyethylene-coated paper support
(Invention 6) or 2 (Invention 7) or 3 (Comparative Example 5) or 4 (Comparative Example 6), and the respective layers were simultaneously coated with a slide curtain coating method at a coating speed of 150 m / min. A coating was prepared. In Comparative Example 7, the first layer (50 μm) was filtered after the coating solution was filtered in the same manner as in Example 1.
m), the second layer (100 μm), the third layer-2 (65 μm)
m), the fourth layer-1 (15 μm) in order of each layer by a slide curtain coating method at an application speed of 150 m / mi.
n to perform simultaneous multi-layer coating to prepare a coating film. Immediately after coating, all coating films in Example 2 were cooled in a cooling zone maintained at 6 ° C. for 10 seconds, and then blown with hot air at 25 ° C. and 15% relative humidity until the water content of the coating film reached 200%. It was dried (coating temperature: 12 ° C.) and further blown with hot air at 48 ° C. and 10% relative humidity (coating temperature: 23 → 48 ° C.) to completely dry. Under all coating conditions, the coating was completely dried within 4 minutes of application. 20 ~ 25 ° C after drying,
After adjusting the humidity for 2 minutes in an atmosphere having a relative humidity of 40 to 60%, the sample was wound up to obtain an image forming material having a porous coating film. The visual state of the dried coating film and the ink absorbency by printing were evaluated.

The conditions for forming the fourth layer of each sample are described below. However, as described above, Comparative Example 7
Except for the above, the first to third layers are the same as in the first embodiment.

The present invention 6 is the same as Example 1 of the fourth layer-1 coating solution (thermoplastic fine particle-containing layer). However, the viscosity of the coating solution at 40 ° C. was 70 mPa · s, and the viscosity of the coating solution at 15 ° C. was 2
Adjusted to 30 mPa · s, the first with a wet film thickness of 15 μm,
Simultaneous multi-layer coating was performed with a few layers.

The fourth layer-2 coating solution (thermoplastic fine particle-containing layer) of the present invention 7 is as follows: (1) 600 ml of styrene-acrylic acid copolymer latex (particle size: 0.3 μm, Tg: 50 ° C., MFT: 50 ° C.) Solid content 50% (w / v) (2) Polyvinyl alcohol (Kuraray Industries, Ltd .: PVA235) 7% aqueous solution 300 ml (average degree of polymerization 3500) 300 ml (3) Saponin 50% aqueous solution 40 ml (4) pH 4 with nitric acid After adjusting to 5, the total amount is made up to 1000 ml with pure water. The viscosity of the coating solution at 40 ° C. was 400 mPa · s, and the viscosity of the coating solution at 15 ° C. was 1400 mPa · s. Simultaneous multilayer coating was performed together with the first, second and third layers at a wet film thickness of 15 μm.

The fourth layer-3 coating solution (layer containing thermoplastic fine particles) of Comparative Example 5 was as follows: (1) 800 ml of styrene-acrylic acid copolymer latex (particle size: 0.3 μm, Tg: 50 ° C., MFT: 50 ° C.) Solid content 50% (w / v) (2) Saponin 50% aqueous solution 40 ml (3) After adjusting the pH to 4.5 with nitric acid, make up to 1000 ml with pure water. The viscosity of the coating solution at 40 ° C. was 20 mPa · s, and the viscosity of the coating solution at 15 ° C. was 70 mPa · s. 10. wet film thickness
Simultaneous multi-layer coating was performed with the first, second and third layers at 3 μm.

The coating solution for the fourth layer-4 of Comparative Example 6 (the layer containing thermoplastic fine particles) is as follows: (1) 800 ml of styrene-acrylic acid copolymer latex (particle size: 0.3 μm, Tg: 50 ° C., MFT: 50 ° C.) Solid content: 50% (w / v) (2) 10% aqueous solution of polyvinyl alcohol (Kuraray Industries Co., Ltd .: PVA235) (average degree of polymerization: 3500) 171.4 ml (3) Saponin 50% aqueous solution 40 ml (4) nitric acid After adjusting to pH 4.5, the total volume is adjusted to 1000 ml with pure water. The viscosity of the coating solution at 40 ° C. was 800 mPa · s, and the viscosity of the coating solution at 15 ° C. was 3500 mPa · s. Simultaneous multilayer coating was performed together with the first, second and third layers at a wet film thickness of 11.3 μm.

In Comparative Example 7, the first and second layers are the same as in Example 1. The third layer-2 coating solution was changed as follows. That is,
The following additives were sequentially mixed with 650 ml of the silica dispersion liquid 2 at 40 ° C while stirring.

(1) 201.6 ml of a 7% aqueous solution of polyvinyl alcohol (PVA235 manufactured by Kuraray Industries, Ltd.) (average degree of polymerization: 3500) (2) Silicon dispersion (BY-22 manufactured by Dow Corning Silicone Toray Co., Ltd.) -839) 15 ml (3) Make up the total amount to 1300 ml with pure water.

The pH of the coating solution is about 4.5, the viscosity at 40 ° C. is 25 mPa · s, and the viscosity of the coating solution at 15 ° C. is about 2500
mPa · s.

The fourth layer-1 coating solution (thermoplastic fine particle-containing layer) is the same as in Example 1. The viscosity of the coating solution at 40 ° C. is 70
mPa · s, viscosity of the coating solution at 15 ° C is 230 mPa · s
Met. The first layer (50 μm) and the second layer (100 μm)
m), 3rd layer-2 (65 μm), 4th layer-1 (15 μm)
m), and the layers were simultaneously coated. Each sample was evaluated by the following evaluation methods, and the results are shown in Table 2.

Coating State After the unprinted image forming material was pressed by a hot roll heated to 120 ° C. to perform the densification treatment of the thermoplastic organic fine particles, the occurrence of cracks and the surface gloss of the coating film on the surface were determined. It was visually evaluated. ◎ No cracks and good gloss ○ Cracks are slightly seen but gloss is good × Cracks are slightly seen and gloss is very deteriorated Ink Absorption Color inkjet printer PM-700C manufactured by Seiko Epson Corporation Was discharged onto the surface of the image forming material. Here, as an output image, high-definition color digital standard image data “N5
・ Bicycle ”(issued in December 1995) was used. Further, after the recording, the thermoplastic organic fine particles were densified by pressing with a hot roll heated to 110 ° C. ◎ A good image was obtained. ○ A good image was obtained, but ◎ was slightly inferior. × There were places where ink overflow occurred.

[0130]

[Table 2]

Table 2 shows that the coating method of the present invention is excellent. In particular, in Comparative Example 7, since the viscosity of the third layer was not sufficiently high with respect to the viscosity of the fourth layer, the coating state was poor.

Example 3 The coating solutions of the first layer, the second layer, the third layer-1 and the fourth layer-1 of Example 1 were prepared and filtered, and then the first layer was coated on a polyethylene-coated paper support. 50 μm), second layer (100 μm), third
Each layer was simultaneously and multi-layer coated by a slide curtain coating method at a coating speed of 200 m / min so that a layer-1 (50 μm) and a fourth layer-1 (15 μm) were formed in this order to form a coating film. Immediately after coating, the coating was cooled in a cooling zone maintained at 6 ° C.
After cooling for 2 seconds, a hot air of 48 ° C. and a relative humidity of 10% is blown onto the coating film to change the wind speed when drying (coating temperature 29).
℃) Completely dried. The time required for drying was changed by changing the wind speed blown to the coating film. After drying 2
After adjusting the humidity for 2 minutes in an atmosphere of 0 to 25 ° C. and a relative humidity of 40 to 60%, the sample was wound up to obtain an image forming material having a porous coating film. The visual state of the dried coating film and the dot shape by printing were evaluated by the following methods, and the results are shown in Table 3.

Coating State After the unprinted image forming material is pressed by a hot roll heated to 120 ° C. to perform the densification treatment of the thermoplastic organic fine particles, the state of occurrence of cracks and the surface gloss of the coating film on the surface are determined. It was visually evaluated.無 い No cracking, good gloss × No cracking and significant disturbance of coating film Dot shape Discharged onto the surface of the image forming material using a color inkjet printer PM-700C manufactured by Seiko Epson Corporation. Here, as an output image, high-definition color digital standard image data “N5
・ Bicycle ”(issued in December 1995) was used. Further, after the recording, the thermoplastic organic fine particles were densified by pressing with a hot roll heated to 110 ° C. The printed portion was observed under magnification using a microscope, and the dot shape of the portion where the ink was attached was evaluated. ◎ A good dot shape was obtained. ○ A good dot shape was obtained, but it was slightly inferior to ◎ × The dot shape was broken.

[0134]

[Table 3]

Table 3 shows that the coating method of the present invention is excellent. Example 4 The first layer, the second layer, and the third layer-1 were prepared and filtered under the same conditions as in Example 1. The fourth layer was prepared by changing the latex to be added to the coating solution to prepare a coating solution, followed by filtration (fourth layers-1, 5). First layer (50 μm), second layer (100 μm), third layer-1 on polyethylene-coated paper support
(50 μm), fourth layer-1 (15 μm) or fourth layer—
5 (15 μm) were applied simultaneously at a coating speed of 200 m / min by a slide curtain coating method to form a coating film. Immediately after the coating, the coating was cooled in a cooling zone maintained at 6 ° C. for 10 seconds, and then the coating film was dried by blowing hot air. The coating film was dried by changing the temperature and humidity conditions of the hot air for drying in three stages according to the water content of the coating film. First, hot air having a temperature of 25 ° C. and a relative humidity of 15% is blown and dried under common conditions (drying condition-1 in Example 1) until the water content of the coating film becomes 200% (the coating film temperature at this time). 12 ° C.) and drying conditions 2 and 3 of Example 1 were completely changed by changing the temperature and humidity conditions of the hot air as shown in Table 4 below. The coating was completely dried within 4 minutes of application under all drying conditions. 20 to 25 after drying is completed
The sample was wound up in an atmosphere at 40 ° C. and a relative humidity of 40 to 60% for 2 minutes to wind up the sample to obtain an image forming material having a porous coating film. The visual state of the dried coating film and the ink absorbency by printing were evaluated.

The coating films of the present invention 11 and comparative example 11 were prepared as follows. Fourth layer-5 coating solution (thermoplastic fine particle-containing layer) (1) Styrene-acrylic acid copolymer latex 600 ml (particle diameter 0.3 μm, Tg 70 ° C., MFT 75 ° C.) Solid content 50% (w / v) (2) 71.4% aqueous solution of polyvinyl alcohol (Kuraray Industries, Ltd .: PVA235) (average degree of polymerization: 3500) 171.4 ml (3) 50% aqueous solution of saponin 40 ml (4) After adjusting the pH to 4.5 with nitric acid, adjust the total amount with pure water Finish to 1000ml. The viscosity of the coating solution at 40 ° C. was 80 mPa · s, and the viscosity of the coating solution at 15 ° C. was 250 mPa · s.

A first layer (50 μm), a second layer (100 μm), a third layer-1 (50 μm) and the fourth layer-5 (15 μm) of Example 1 were simultaneously coated.

The coating films of Inventions 12, 13 and Comparative Example 10 are as follows. The first layer (50 μm) and the second layer (1
00 μm), third layer-1 (50 μm), fourth layer-1 (1
5 μm) at the same time.

Coating State After the unprinted image-forming material was pressed by a hot roll heated to 110 ° C. to densify the thermoplastic organic fine particles, the state of cracking and the surface gloss of the coating film on the surface were determined. It was visually evaluated. ◎ No cracks, good gloss × Many cracks, poor gloss

[0140]

[Table 4]

Table 4 shows that the coating method of the present invention is excellent. Example 5 After preparing and filtering the coating solution of the first layer, the second layer, the third layer-1, and the fourth layer-1 of Example 1, the first layer (50 μm) was formed on a polyethylene-coated paper support. Each layer was coated by a slide bead coating method at a coating speed of 100 in order of two layers (100 μm), third layer-1 (50 μm), and fourth layer-1 (15 μm).
At the same time, a multilayer coating was performed at m / min to prepare a coating film.

Immediately after coating, the coating was cooled in a cooling zone maintained at 3 ° C. for 20 seconds. A comparison was made between two types of the transporting method of the support in the cooling zone: the horizontal transporting method and the vertical transporting method. Thereafter, hot air at 48 ° C. and a relative humidity of 10% was blown onto the coating film to completely dry it. The time required for drying was changed by changing the wind speed blown to the coating film. After the drying was completed, the sample was conditioned in an atmosphere of 20 to 25 ° C and a relative humidity of 40 to 60% for 2 minutes to wind up the sample to obtain an image forming material having a porous coating film. The visual state of the dried coating film and the dot shape by printing were evaluated by the following evaluation methods.
Shown in

Coating state After the unprinted image forming material was pressed by a hot roll heated to 120 ° C. to perform the densification treatment of the thermoplastic organic fine particles, the state of occurrence of cracks and the surface gloss of the coating film on the surface were determined. It was evaluated visually.が No cracks and good gloss × No significant disturbance of the coating Dot shape Discharged onto the surface of the image forming material using a color inkjet printer PM-700C manufactured by Seiko Epson Corporation. Here, as an output image, high-definition color digital standard image data “N5
・ Bicycle ”(issued in December 1995) was used. Further, after the recording, the thermoplastic organic fine particles were densified by pressing with a hot roll heated to 110 ° C. The printed portion was observed under magnification using a microscope, and the dot shape of the portion where the ink was attached was evaluated. ◎ Good dot shape was obtained. × Dot shape was broken.

[0144]

[Table 5]

Table 5 shows that the coating method of the present invention is excellent.

[0146]

According to the present invention, it has been possible to provide a method for efficiently producing a high-quality, high-quality ink jet image forming material.

Continued on the front page F-term (reference) 2C056 FC06 2H086 BA13 BA15 BA16 BA33 BA34 BA41 4D075 AE23 BB18Y BB22X BB24Z BB57Z BB93X BB93Y BB93Z BB95Z CA02 CA32 CA35 CA38 CA47 DA04 DB18 DB36 DC27 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB13 EB12 EB45 EC03 EC05

Claims (9)

[Claims] 1. A method for producing an ink-jet image-forming material having an ink receiving layer containing thermoplastic resin particles as an outermost layer on a support, and having an ink solvent absorbing layer adjacent to the ink receiving layer. After simultaneously coating the receiving layer and the ink solvent absorbing layer, the coating temperature is once cooled to 1 to 15 ° C., and the temperature range of the coating temperature is 10 ° C. or more and Tg of the thermoplastic fine particles of the outermost layer or below or A method for producing an ink jet image forming material, wherein drying is performed at MFT or lower. 2. The physical properties of the outermost layer of the coating solution on the support at a coating solution temperature of 15 ° C. during simultaneous multilayer coating are 100 to 2000.
The method for producing an ink-jet image forming material according to claim 1, wherein a coating solution having a mPa · s is used. 3. The method for producing an ink-jet image forming material according to claim 1, wherein the time until the completion of the drying is determined by a numerical value represented by the following formula. (Equation 1) 4. A wet bulb temperature of 5 to 40 ° C. and a film surface temperature of 10 to 5
The method for producing an ink-jet image forming material according to claim 1, wherein the coating film is dried by blowing hot air at 0 ° C. 5. The method for producing an ink-jet image forming material according to claim 1, wherein the temperature of the coating liquid is 30 ° C. or higher and Tg of the thermoplastic resin fine particles or lower. 6. The method for producing an ink-jet image forming material according to claim 1, wherein the cooling method immediately after the coating is performed by a horizontal set method. 7. The ink solvent-absorbing layer of the ink-jet image forming material produced by the production method according to claim 1, wherein the ink solvent-absorbing layer has a porous structure,
An ink jet image forming material comprising at least one kind of inorganic fine particles selected from at least one kind of colloidal silica, hydrated alumina, and vapor phase alumina. 8. A thermoplastic resin fine particle of an inkjet image forming material produced by the production method according to claim 1, wherein the thermoplastic resin fine particle is a vinyl chloride, styrene, acrylic, urethane, polyester, Ethylene, vinyl chloride-vinyl acetate, vinyl chloride-vinylidene chloride, vinyl chloride-acrylic, vinylidene chloride-acrylic, styrene-butadiene-based, at least one latex particle selected from styrene-acrylic-based materials. An ink jet image forming material, characterized in that: 9. Tg and MFT of thermoplastic resin fine particles
9. The ink-jet image forming material according to claim 8, wherein both are 40 to 100 ° C.