JP2002248848A - Ink jet recording method and paper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve deterioration of an image by preventing an ink jet recording paper having a void-type ink absorbing layer, the ink absorbing speed of which is high, from turning into brown with a harmful gas or the like with no special process. SOLUTION: In an ink jet recording method, the discharging amount of 10 to 30 mL/m<2> of an ink including a water-soluble dye, water and a water-soluble organic solvent is discharged to the ink jet recording paper having a first porous layer with a porous structure as an outermost surface layer and dried under room temperature to a steady state, the relationship between the ink jet recording paper and the ink satisfies formula (1): Va/Vb<=0.4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording sheet (hereinafter, also simply referred to as a recording sheet), and more particularly, to an ink jet recording sheet which is excellent in ink absorbency and has little image deterioration due to toxic gas. The present invention also relates to an ink jet recording method for ejecting and recording ink.

[0002]

2. Description of the Related Art Ink-jet recording is a method in which fine droplets of ink are caused to fly according to various operating principles and adhere to a recording sheet such as paper to record images and characters. It has advantages such as easy noise and multicoloring.

With respect to clogging and maintenance of nozzles, which has been a problem in the above recording method, improvements have been made in both ink and apparatus. At present, various fields, such as various printers, facsimile machines, and computer terminals, have been rapidly developed. It is widespread.

In particular, since the image quality of printers has recently become higher and the image quality has reached photo quality, it is necessary to realize the image quality of the recording paper and to reproduce the texture (gloss, smoothness, firmness, etc.) of the photo. Is required.

[0005] In order to reproduce the texture of a photograph, a so-called swelling type in which a hydrophilic binder such as gelatin or polyvinyl alcohol is coated on a support as a conventional recording paper is known. It has the disadvantages that it is slow, the surface is sticky after printing, and the image is easily blurred due to humidity during storage. In particular, since the absorption speed is low, ink droplets are mixed before they are absorbed, and bleeding between different colors (bleeding) and mottle (beading) in the same color are likely to occur, making it extremely difficult to achieve photographic image quality. It is.

The so-called void type is becoming the mainstream in place of the swelling type, and is characterized by a high absorption rate because ink is absorbed into fine voids. Examples of recording paper that achieves photographic image quality and photographic texture in this way include:
JP-A-10-119423 and JP-A-10-119424
No., 10-175364, 10-193776
No., 10-193776, 10-217601
No. 11-20300, No. 11-106694,
JP-A-11-321079, JP-A-11-348410, JP-A-10-178126, JP-A-11-348409, JP-A-2000-27093, JP-A-2000-94830,
Nos. 2000-158807 and 2000-21124
No. 1 and the like.

On the other hand, in addition to image quality and texture, demands for durability and image storability have become higher, and many attempts have been made to achieve light resistance, moisture resistance, water resistance, etc., at the level of silver halide photography. Japanese Patent Application Laid-open No.
-74192, 57-87989, 57-74
No. 193, No. 58-152072, No. 64-3647
9, JP-A-1-95091 and JP-A-1-115677
Nos. 3-13376, 4-7189, and 7-1
Nos. 95824, 8-25796, 11-3210
No. 90, No. 11-277893, JP-A-2000-37
No. 951 and many other techniques are disclosed.

[0008] In the case of the gap type recording paper, there is a problem that not only so-called light resistance, but also susceptibility to discoloration due to harmful gas occurs due to the gap structure. In particular, it is likely to occur with phthalocyanine-based aqueous dyes used in general color inkjet printers.

Although the mechanism of this discoloration is still unclear, the fine void structure has a high surface area and an active surface of inorganic fine particles, so that ozone, oxidants, SOx, NOx, etc. It is believed that trace amounts of active harmful gases are decomposing the dye.

Techniques for improving the phenomenon of discoloration are described in JP-A-63-252780, JP-A-64-11877, JP-A-1-108083, JP-A-1-216881, and JP-A-1-216881.
-218882, 1-258980, 2-18
Nos. 8287, 7-237348, 7-26668
No. 9 and No. 8-164664, etc. However, since the recording medium for photographic image quality in which the void structure is finer is further deteriorated, the effect of the conventional improved technology is insufficient, and Improvement is desired.

Although this problem is small in the swellable recording paper, it is difficult to improve the ink absorption speed.

The problem of discoloration and discoloration can be solved by an ink jet recording method using a pigment ink, but problems such as glare (bronzing) on recording paper have not reached a level at which sufficient image quality can be obtained. Further, a gas shut-off method such as laminating the print or putting it in a frame, or JP-A-53-27426 and JP-A-59-22
No. 2381, No. 62-277881, JP-A-11-1
57207, 11-245507, JP-A-2000
A method of printing a recording paper containing thermoplastic fine particles on the surface thereof as exemplified in JP-A-71608 and then subjecting the recording paper to a heat or pressure treatment to develop a gas barrier layer is very effective, but any of them is effective. Post-processing is required, and extra steps are a burden. In particular, in the case of large-format ink jet recording having a width of 60 cm or more, not only lamination processing and heat roll processing are troublesome, but also dedicated equipment is expensive and it cannot be said that it is widely used widely.

JP-A-63-60784 describes an ink jet recording paper having a void layer having organic fine particles and inorganic fine particles. However, these organic fine particles were dissolved only in a special solvent and did not dissolve in an organic solvent used in a general ink for an ink jet printer, and thus could not be used for ordinary ink jet recording.

[0014]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to eliminate the need for a special process for an ink jet recording paper having a void-type feature with a high ink absorption speed. And image deterioration due to harmful gas.

[0015]

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

1. An ink containing a water-soluble dye, water and a water-soluble organic solvent is applied to an ink-jet recording sheet having a first porous layer having a porous structure as an outermost layer in an amount of 10 to 3 inks.
An ink jet recording method for discharging at any discharge amount of 5 ml / m ² and drying at room temperature to a constant state, wherein the relationship between the ink jet recording paper and the ink satisfies the following general formula (1). Recording method.

The general formula (1): Va / Vb ≦ 0.4 Va is the amount of water transfer at a contact time of 0.8 seconds when a portion where the ink is applied to the ink jet recording paper at the above discharge amount is measured by Bristow. And Vb is the amount of water transferred at a contact time of 0.8 seconds when a portion where the ink is not applied to the ink jet recording paper is subjected to Bristow measurement.

2. SP value of 18.414 to 30.69
(MPa) alcohol-based and either and having a boiling point of not lower than 120 ° C. ^1/2 water-soluble organic solvent, water-soluble dyes, and using an ink containing water, dissolved or swelled by the alcohol-soluble organic solvent An ink-jet recording method comprising recording on an ink-jet recording sheet having water-insoluble organic fine particles as a main component and having a first porous layer having a porous structure.

In a preferred embodiment, the alcohol-based water-soluble organic solvent is triethylene glycol monobutyl ether.

3. The water-soluble organic solvent has an SP value of 18.
An alcohol-based water-soluble organic solvent having a boiling point of not less than 414 to 30.69 (MPa) ^1/2 and a boiling point of 120 ° C. or more, wherein the main component of the first porous layer is the alcohol-based water-soluble organic solvent 2. The ink-jet recording method according to 1, wherein the water-insoluble organic fine particles dissolve or swell in water.

In a preferred embodiment, the alcohol-based water-soluble organic solvent is triethylene glycol monobutyl ether.

4. An inkjet recording paper having a first porous layer having a porous structure as an outermost layer, and having an SP value of 18.414 to 30.69 (MPa) ^1/2 and a boiling point of 120 ° C. or higher. When an aqueous solution containing any of 10 to 40% by mass of a system water-soluble organic solvent is applied to the surface of the ink jet recording paper at 20 ml / m ² and dried to a constant state at room temperature, the ink jet recording paper becomes An ink jet recording paper satisfying the following general formula (2).

Vc / Vd ≦ 0.4 Vc is the amount of water transferred at a contact time of 0.8 seconds when a portion where the aqueous solution is applied and dried is measured by Bristow, and Vd is the aqueous solution. Is the amount of water transfer at a contact time of 0.8 seconds when a portion to which no is given was subjected to Bristow measurement.

5. An ink absorbing layer having a first porous layer having a porous structure as an outermost layer, wherein the ink absorbing layer has an SP value of 18.414 to 30.69 (MPa) ^1/2
An ink jet recording sheet comprising water-insoluble organic fine particles which dissolve or swell in an alcohol-based water-soluble organic solvent having a boiling point of 120 ° C. or higher.

The first porous layer has an SP value of 18.4.
It is preferable to contain, as a main component, water-insoluble organic fine particles which are any of 14 to 30.69 (MPa) ^1/2 and which dissolve or swell in an alcohol-based water-soluble organic solvent having a boiling point of 120 ° C. or higher. It is an aspect.

6. The ink jet recording paper is a first
Of the porous layer has an SP value of 18.414 to 30.
69 (MPa) ^1/2 and boiling point is 120 ° C
Water-insoluble organic fine particles that dissolve or swell in the alcohol-based water-soluble organic solvent described above, and further have a second porous layer mainly composed of inorganic fine particles and a water-soluble binder. The ink jet recording paper according to the above.

It is a preferred embodiment that the ink jet recording paper has a non-water-absorbing support.

The alcohol-based water-soluble organic solvent is
A preferred embodiment is diethylene glycol monobutyl ether.

7. An ink-absorbing layer having a first porous layer and a second porous layer containing inorganic fine particles and a water-soluble binder as main components, wherein the film thickness of the first porous layer is Wherein the thickness of the second porous layer is 80% or more of the total thickness of the ink absorbing layer. Item 7. The ink jet recording paper according to item 1.

8. The inkjet recording paper according to any one of claims 5 to 7, wherein the water-insoluble organic fine particles have a number average particle diameter of 0.01 to 1 µm.

9. The length of the shortest side is 60cm or more and 10
m. The inkjet recording paper according to any one of 4 to 8, wherein m is equal to or less than m.

Hereinafter, the present invention will be described in detail. The recording paper used in the present invention preferably has a high ink absorption rate in order to achieve photographic image quality, and therefore preferably has a void at least on the outermost surface. Preferably, it is a recording paper having an ink absorbing layer coated on a support and having an ink absorbing layer on the outermost surface.

There are voids in the porous layer having a porous structure, and the form of the voids can be confirmed by observation with an electron microscope.

It is preferable that the gaps are not isolated from each other, but are continuous with each other. In this case, as the definition of the pore size, for example, a measurement value by a mercury intrusion method can be used.

In a gap type recording sheet, a gap filled with fine particles is used as a gap in many cases. Therefore, the pore diameter can be expressed from the size of the particles and the filling ratio. The size of the particles preferably used in the present invention is 0.01 to 1 μm, more preferably 0.02 to 1 μm.
0.1 μm, and the porosity is 10 to 70%, more preferably 20 to 60%.

The ink jet recording method according to claim 1 will be described. The ink jet recording method is characterized in that an ink containing a water-soluble dye, water and a water-soluble organic solvent is added at an amount of 10 to 35 ml / m ² to an ink jet recording paper having a first porous layer having a porous structure as the outermost layer. When performing ink jet recording by discharging with such a discharge amount,
The relationship between the ink jet recording paper and the ink satisfies Va / Vb ≦ 0.4 in the general formula (1).

Va is the amount of water transfer at a contact time of 0.8 seconds when a portion where the ink is applied to the ink jet recording paper at the discharge amount is measured by Bristow, and Vb is the ink transferred to the ink jet recording paper. Is the amount of water transfer at a contact time of 0.8 seconds when a portion to which no is given was subjected to Bristow measurement.

In the ink jet recording paper according to the first aspect, the ratio (Va / Vb) of the amount of water transfer (Va / Vb) at a contact time of 0.8 seconds in Bristow measurement is 0 with respect to the unrecorded portion of the recording surface after ink jet recording. 0.4 or less, that is, the amount of water absorption must be reduced, and the rate of reduction (the ratio of the amount of water absorption before and after inkjet recording) is 40% or less. A more preferred reduction rate is 20% or less.

The Bristow measurement was carried out in a liquid absorption test (see J. TAPPI paper pulp test method No. 51).
According to the test method described in The liquid used for the measurement is water, but for the purpose of facilitating the measurement, a very small amount of a dye or the like may be dissolved in water and colored.

In the present invention, water containing 0.1% or less of a dye is also regarded as water.

Hereinafter, a method for measuring the amount of water transferred by Bristow measurement will be described. The amount of liquid transfer is described in J.P. TAPPI Paper
-PulpTest Method No. 51-87
The measurement was carried out according to the method described in 1. Related documents include TAPPI J, 65 (12) 98 (1982).
There is. In the present invention, the amount of transition (ml / m ² ) at a contact time of 0.8 seconds was obtained as the volume of the void using a Bristow test apparatus type II manufactured by Kumagai Riki Kogyo Co., Ltd. The liquid used in the test of the present invention was C.I. I. Ac
It is a 0.05% aqueous solution of id Red 52.

The term "dried to a constant state at room temperature" in the present invention refers to a state in which the evaporation of water has substantially reached an equilibrium with the general surrounding environment, preferably at 23 ° C.
-About 1 hour after the application of the ink or aqueous solution at 55% RH.

In the present invention, as a specific method of expressing a decrease in the absorption rate, for example, the gap existing before the ink jet recording is removed after recording. No longer a void;
2. the number of voids is reduced; For example, the pore diameter is reduced.

The above 2. Is preferable, and the maximum peak height existing at 0.01 to 1 μm in the pore size distribution is preferably 40% or less.

The above 3. It is also preferable that “the diameter of the voids is reduced”. When the maximum peak existing at 0.01 to 1 μm in the void diameter distribution is defined as the void diameter, the value of the void diameter before and after recording is reduced to 60% or less. Is preferred.

However, the most preferable is the above-mentioned 1. When the surface of the recording portion was observed with an electron microscope after the recording of No. 1, the state was such that "voids were not observed".

Further, the following method is preferably used as a specific method for expressing the above-mentioned morphological change of the void.

After the ink is applied to the recording paper, the water in the ink gradually evaporates, but the evaporation of the water-soluble organic solvent is slow, and the ratio of the water-soluble organic solvent as the liquid remaining on the recording paper gradually increases. That is, substances that are insoluble in water and soluble in these water-soluble organic solvents gradually start dissolving as the ink dries. In other words, when inkjet recording is performed on recording paper containing “water-insoluble organic fine particles that dissolve or swell with the water-soluble organic solvent in the ink”, some or all of the organic fine particles dissolve or swell after drying of the ink. Thereby, the gap can be closed or the gap diameter can be reduced.

Further, a layer mainly composed of hydrophobic organic fine particles such as polystyrene is provided on the surface of the recording paper, and a plasticizer such as phthalate is contained in the lower layer. When the ink is applied thereto, after drying, the plasticizer is dissolved and diffused by the water-soluble organic solvent in the ink, and the organic fine particles are plasticized to form a film, thereby closing the voids and reducing the void diameter.

A layer mainly composed of organic fine particles made of an alkali-soluble resin such as hydroxypropylmethylcellulose phthalate is provided on the surface of the recording paper. On the other hand,
The lower layer contains an organic base that is hardly soluble in water and diffuses with the water-soluble organic solvent in the ink. When the ink is applied thereto, after drying, the organic base is dissolved and diffused by the water-soluble organic solvent in the ink, thereby increasing the surface pH and dissolving the organic fine particles, thereby closing the pores and reducing the pore diameter. .

Further, a layer mainly composed of organic fine particles composed of an alkali-soluble resin is provided on the surface of the recording paper in the same manner as described above. On the other hand, the lower layer contains a chelating agent that is hardly dissolved in water and is diffused by the water-soluble organic solvent in the ink,
Further, a metal hydroxide insoluble in water such as zinc hydroxide is contained in the lower layer. When the ink is applied thereto, the chelating agent diffuses after drying and causes a chelation reaction with the metal in the metal hydroxide. As a result, an alkali is generated, which increases the pH of the surface and dissolves the organic fine particles, thereby closing the voids and reducing the void diameter.

The ink according to the first aspect contains a water-soluble dye, water, and a water-soluble organic solvent, and other additives can be added as needed. In particular, the water-soluble organic solvent is always added for the purpose of preventing precipitation of the dye due to drying of the ink near the nozzle. The water-soluble organic solvent may be any organic solvent that is compatible with water, or a mixture of a plurality of types may be used.

Examples of the water-soluble organic solvent include alcohols (eg, butanol, isobutanol, secondary butanol, tertiary butanol, pentanol, hexanol, cyclohexanol, benzyl alcohol), and polyhydric alcohols (eg, Ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol,
Dipropylene glycol, polypropylene glycol,
Butylene glycol, hexanediol, pentanediol, glycerin, hexanetriol, thiodiglycol, etc.), alkyl ethers of polyhydric alcohols (for example, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol dimethyl ether, Diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether,
Triethylene glycol monoethyl ether, triethylene glycol monomethyl ether, triethylene glycol monobutyl ether, triethylene glycol diethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol monomethyl ether,
Tetraethylene glycol monoethyl ether, tetraethylene glycol monobutyl ether, tetraethylene glycol dimethyl ether, tetraethylene glycol diethyl ether, etc.), amines (for example, ethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, Morpholine, N-ethylmorpholine, ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, polyethyleneimine, pentamethyldiethylenetriamine, tetramethylpropylenediamine and the like, amides (for example, formamide, N, N-dimethylformamide, N, N-dimethylacetamide, etc.), heterocycles (eg, 2-pyrrolidone, N-methyl 2-pyrrolidone, cyclohexyl pyrrolidone, 2-oxazolidone, 1,3-dimethyl -
2-imidazolidinone, etc.), sulfoxides (for example,
Dimethyl sulfoxide), sulfones (eg, sulfolane) and the like.

Particularly preferred water-soluble organic solvents are polyhydric alcohols, alkyl ethers of polyhydric alcohols, and heterocycles, and it is preferable to select two or three from these.

The water-soluble organic solvent has an SP value of 18.414.
~30.69 (MPa) and the boiling point is either ^1/2 is preferably an alcohol-based water-soluble organic solvent above 120 ° C.. The content of the water-soluble organic solvent in the ink composition is preferably from 10 to 40% by mass.

The SP value is a solubility parameter and is one useful measure for predicting the solubility of a substance. Here, the unit is (MPa) ^1/2 and indicates a value at 25 ° C. "POLYMER HANDBOOK"
(J. Brandrup et al., A Wiley-inté)
rsscience Publication) IV-3
In addition to the description on page 37, SP values of organic solvents are described in various documents.

The alcohol-based water-soluble organic solvent refers to a water-soluble organic solvent having an alcoholic hydroxyl group in a molecule, and includes a polyhydric alcohol compound and a polyalkyl alcohol compound partially alkylated. Examples include butanol, isobutanol, secondary butanol, tertiary butanol, pentanol, hexanol, cyclohexanol, benzyl alcohol, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol,
Dipropylene glycol, polypropylene glycol,
Butylene glycol, hexanediol, pentanediol, glycerin, hexanetriol, thiodiglycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether,
Examples thereof include diethylene glycol monobutyl ether, triethylene glycol monoethyl ether, triethylene glycol monomethyl ether, triethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, tetraethylene glycol monoethyl ether, and tetraethylene glycol monobutyl ether.

Particularly preferred water-soluble organic solvents are polyhydric alcohols and alkyl ethers of polyhydric alcohols.
It is preferable that two or three kinds are selected from these.

Among the hydrophilic organic solvents according to the present invention, SP
(Solubility parameter) values between 18.414 and 30.69
As the hydrophilic organic solvent having a range of (MPa) ^1/2 , ethylene glycol, diethylene glycol, triethylene glycol, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether and the like are preferably used, and triethylene glycol monobutyl ether is particularly preferably used. Glycol monobutyl ether or diethylene glycol monobutyl ether (SP value 19.43
7, boiling point 230 ° C).

The ink contains at least one of water-soluble dyes such as direct dyes, acid dyes, basic dyes, reactive dyes, and food dyes known by ink jet. The concentration of the dye / pigment in the ink is usually 0.1 to 5%.

The ink is usually 25 to 60 dy at 20 ° C. in order to improve the wettability on the recording paper.
It preferably has a surface tension in the range of n / cm, preferably 30 to 50 dyn / cm.

It is desirable that the pH of the ink is 7 or more in order to improve the solubility of the dye. For this purpose, a known pH adjuster can be used.

Other additives for the ink include, for example, metal sequestering agents, fungicides, viscosity modifiers, surface tension regulators, wetting agents, surfactants and rust inhibitors. The concentration of these additives in the ink is usually 0.01 to 5%.

The ejection amount of the ink is 10 ml / m ² or more, and the maximum ejection amount is preferably 35 ml / m ² or less. If the ejection amount is larger than this, it is necessary to increase the thickness of the coating layer in order to increase the absorption capacity of the recording paper, which may cause various adverse effects such as cracks. A preferable maximum discharge amount of the ink is 25 ml / m ² or less.

In drying the ink jet recording paper according to the first aspect after recording, a heat source or a blower may be used for the purpose of accelerating the drying of water, but natural drying is preferable in view of the load of the apparatus and processing.

Next, the ink jet recording method according to claim 2 is described.
The recording method will be described. The inkjet recording method
Has an SP value of 18.414 to 30.69 (MPa) ^1/2
Alcohols having a boiling point of at least 120 ° C
Ink containing water-soluble organic solvent, water-soluble dye, and water
Dissolved in the alcohol-based water-soluble organic solvent using
Alternatively, the main component is water-insoluble organic fine particles that swell,
Ink jet having first porous layer having pore structure
It is characterized by recording on recording paper. Main in the present invention
The component is 50% by mass based on the solid content in the first porous layer.
More than 100% by mass.
Or 75 to 100% by mass.

The “water-insoluble organic fine particles that are dissolved or swelled by an alcohol-based water-soluble organic solvent (also referred to simply as organic fine particles)” are preferably polymers having a molecular weight of 5,000 or more, and examples of the material include polyvinyl chloride and polyvinyl chloride. Vinylidene, polyacrylate, polymethacrylate,
Elastomer, ethylene-vinyl acetate copolymer, styrene- (meth) acryl copolymer, polyester, polyvinyl ether, polyvinyl acetal, polyamide, polyurethane, polyolefin, SBR, NBR, polytetrafluoroethylene, chloroprene, protein, polysaccharide, It is selected from conventionally known ones such as rosin ester and shellac resin. Particularly preferred materials of the organic fine particles are polyvinyl acetal resin, polyurethane resin, rosin ester resin, (meth) acrylate resin, SB
R and the like. Resins consisting of two or more monomers by modification or copolymerization are also preferably used. A resin to which a specific modifying group has been added or a resin from which a leaving group has been removed may be used.
Further, two or more types of materials may be mixed to form organic fine particles, or two or more types of organic fine particles may be mixed and used.

In the present invention, "dissolution" means that the organic fine particles and the water-soluble organic solvent in the ink form a single phase in an equilibrium state, and "swelling" means that the organic fine particles absorb the same water-soluble organic solvent. To increase the volume more than twice. The preferred volume increase rate when swollen is 2 to 8 times.

The organic fine particles must be insoluble in water so as not to be dissolved during ink jet recording. However, it is permissible to absorb water as long as the ink absorption speed is not hindered. Water may be absorbed up to 20% of the mass of the organic fine particles.

A cross-linking agent may be used in the organic fine particles as long as it does not hinder dissolution or swelling in a water-soluble organic solvent. As the cross-linking agent, a conventionally known cross-linking agent can be used regardless of an organic substance or an inorganic substance.

The particle size of the organic fine particles greatly affects the surface gloss of the recording paper. Preferred number average particle size is 0.001
To 2 μm, more preferably 0.01 to 1 μm. As a method for measuring the number average particle diameter, there is a method in which the cross section and the surface of the containing layer are observed with an electron microscope, the particle diameters of a large number of arbitrary particles are determined, and a simple average value (number average) is determined. Each particle size is represented by a diameter assuming a circle equal to the projected area. The shape of the organic fine particles need not be a true sphere, but may be a needle or a plate.

The relationship between the ink jet recording paper and the ink is such that Va / Vb ≦ V / Vb in the ink jet recording method of claim 1 in order to more effectively prevent discoloration and fading.
Preferably, 0.4 is satisfied.

Next, the ink jet recording paper according to claim 4 will be described. The inkjet recording paper has an SP value of 18.414 to 30.69 (MPa) ^1/2.
And an aqueous solution containing an alcohol-based water-soluble organic solvent having a boiling point of 120 ° C. or higher and containing any of 10 to 40% by mass, and a first porous layer having a porous structure as the outermost layer. 20ml / m ^{2 on} the surface of paper
When applied and dried to a constant state at room temperature, the ink jet recording paper has a Vc / Vd of the general formula (2).
≦ 0.4.

Vc has an SP value of 18.414 to 30.6.
9 and an aqueous solution containing an alcohol-based water-soluble organic solvent having a boiling point of 120 ° C. or more and containing any of 10 to 40% by mass is applied to the surface of the inkjet recording paper at 20 ml / m ² , and is constantly applied at room temperature. The amount of water transferred at a contact time of 0.8 seconds when the portion dried to the state was measured by Bristow, and Vd was the water at a contact time of 0.8 seconds when the aqueous solution-unapplied portion of the recording paper was measured by Bristow. Is the amount of transfer.

That is, it is necessary that the portion to which the aqueous solution is applied has a lower water absorption rate than the unrecorded portion.
The reduction rate (the ratio of the water absorption before and after the treatment) may be 40% or less, and the more preferable reduction rate is 20% or less.

The upper limit of the boiling point of the alcohol-based water-soluble organic solvent is not particularly limited, but preferably has a melting point of 30 ° C. or lower.

Specific examples of the alcohol-based water-soluble organic solvent used in the aqueous solution are described above, and among them, diethylene glycol monobutyl ether is preferably used.

The preferred state of the ink-jet recording sheet of the present invention as the ink-jet recording sheet is, as described in detail in the ink-jet recording sheet of claim 1, after the gap existing before applying the aqueous solution is added. No longer a void; 2. the number of voids is reduced; For example, the pore diameter is reduced.

Next, the ink jet recording paper according to claim 5 will be described. The inkjet recording paper has an ink absorbing layer having a first porous layer having a porous structure as the outermost layer, and the ink absorbing layer has an SP value of 1
8.414 to 30.69 (MPa) ^1/2 and contains water-insoluble organic fine particles that dissolve or swell in an alcohol-based water-soluble organic solvent having a boiling point of 120 ° C. or higher. Things.

The water-soluble organic solvent used in the aqueous solution has an SP value of 18.414 to 30.69 (MPa) ^1/2.
And an alcohol-based water-soluble organic solvent having a boiling point of 120 ° C. or higher is selected. The upper limit of the boiling point is not particularly limited, but those having a melting point of 30 ° C. or less are preferred.

As the organic fine particles, water-insoluble ones which are dissolved or swelled by the above-mentioned alcohol-based water-soluble organic solvent are selected.

Also in the ink jet recording paper according to the fifth aspect, in order to more effectively prevent discoloration and fading, the Vc / Vc defined in the ink jet recording paper according to the fourth aspect is preferable.
It is preferable to satisfy Vd ≦ 0.4.

Next, the ink jet recording paper according to claim 6 will be described. The ink jet recording paper is a preferred embodiment of the ink jet recording paper according to claim 4 or 5, wherein the main component of the first porous layer located at the outermost layer has an SP value of 18.414. ~ 3
0.69 (MPa) ^1/2 and the boiling point is 12
Water-insoluble organic fine particles that dissolve or swell in an alcohol-based water-soluble organic solvent at 0 ° C. or higher, and further include a second porous layer mainly composed of inorganic fine particles and a water-soluble binder. It is.

In the present invention, the organic fine particles in the first porous layer are preferably packed in the layer at a high density, and more than 50% by mass based on the total solid content of the layer. In this case, it is particularly preferable that the content be 75% or more in that the effects of the present invention are remarkably exhibited.

The second porous layer contains inorganic fine particles and a water-soluble binder as main components. Specifically, the total mass of the inorganic fine particles and the water-soluble binder is reduced to the total solid content of the second porous layer. On the other hand, it means more than 50% and 100% or less.

In a particularly preferred embodiment of the ink-jet recording paper of the present invention, the first porous layer and the second porous layer containing inorganic fine particles and a water-soluble binder as main components are provided. Having an ink absorbing layer having
The thickness of the porous layer is 2 to the total thickness of the ink absorbing layer.
0% or less, and the thickness of the second porous layer is 80% or more with respect to the total thickness of the ink absorbing layer. In the first porous layer, the ratio of the organic fine particles is preferably larger than 50% by mass relative to the solid content in the layer.

It is preferable that the organic fine particles are filled into the first porous layer at a high density. The proportion in the first porous layer containing the organic fine particles is preferably larger than 50% by mass relative to the solid content in the layer, more preferably 75% or more. In order to effectively block harmful gases, the first porous layer containing organic fine particles is preferably located on the outermost layer.

The first porous layer containing the organic fine particles at a high filling rate generally has a low porosity, and if the ink absorbing layer is formed as a single layer, the thickness becomes large to secure the absorption capacity. . On the other hand, the second porous layer composed of the inorganic fine particles and the water-soluble binder has a high porosity and can absorb a large amount of ink with a thinner layer. Therefore, it is preferable to form an ink absorption layer having both a first porous layer containing organic fine particles and a second porous layer made of inorganic fine particles and a water-soluble binder. The thickness of the first porous layer containing organic fine particles is preferably from 0.1 to 30%, more preferably from 0.5 to 20%, based on the thickness of the ink absorbing layer.

As described above, the ink jet recording paper of the present invention preferably has a second porous layer containing inorganic fine particles and a water-soluble binder as main components. Hereinafter, this preferred second porous layer will be described.

Examples of the inorganic fine particles include light calcium carbonate, heavy calcium carbonate, magnesium carbonate, kaolin, clay, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc hydroxide, zinc sulfide, and carbonate. Zinc, hydrotalcite, aluminum silicate, diatomaceous earth, calcium silicate, magnesium silicate,
Synthetic amorphous silica, colloidal silica, alumina, colloidal alumina, pseudoboehmite, aluminum hydroxide,
Examples thereof include white inorganic pigments such as lithopone, zeolite, and magnesium hydroxide.

In order to obtain high glossiness, the particle diameter of these inorganic fine particles is preferably 0.01 to 1 μm.
More preferably, it is 0.02 to 0.1 μm.

The inorganic fine particles mentioned here may be primary particles or secondary particles. The particle size of the inorganic fine particles is the particle size of the highest order particles observed in the dried film.

In the present invention, even when composite particles composed of inorganic fine particles and a small amount of an organic polymer are used, they are substantially regarded as inorganic fine particles. Also in this case, the particle size of the highest order particles observed in the dried film is defined as the particle size of the inorganic fine particles. In this case, the mass ratio of the organic polymer / inorganic fine particles in the composite particles composed of the inorganic fine particles and a small amount of the organic polymer is approximately 1/100 to 1/4.

The average particle diameter of the inorganic fine particles is determined by observing the cross section and surface of the second porous layer with an electron microscope, calculating the particle diameters of a large number of arbitrary particles, and calculating the simple average value (number average). Desired. Here, each particle size is represented by a diameter assuming a circle equal to the projected area.

In the present invention, it is preferable to use fine particles having a low refractive index from the viewpoints of low cost and high reflection density, and silica, especially silica or colloidal silica synthesized by a gas phase method is more preferable. . Further, fumed silica treated with a cation surface, colloidal silica and alumina treated with a cation, alumina, colloidal alumina, pseudoboehmite and the like can also be used.

Examples of the water-soluble binder used in the ink absorbing layer include polyvinyl alcohol, gelatin, polyethylene oxide, polyvinyl pyrrolidone, polyacrylic acid, polyacrylamide, polyurethane, dextran, dextrin, and carrageenan (κ, ι, λ).
Etc.), agar, pullulan, water-soluble polyvinyl butyral,
Hydroxyethyl cellulose, carboxymethyl cellulose and the like can be mentioned. Two or more of these water-soluble binders can be used in combination. The water-soluble binder preferably used in the present invention is polyvinyl alcohol.

The polyvinyl alcohol preferably used in the present invention includes, in addition to ordinary polyvinyl alcohol obtained by hydrolyzing polyvinyl acetate, polyvinyl alcohol having a cation-modified terminal or anion-modified polyvinyl alcohol having an anionic group. Of modified polyvinyl alcohol.

The polyvinyl alcohol obtained by hydrolyzing vinyl acetate preferably has an average degree of polymerization of 1000 or more, and particularly preferably has an average degree of polymerization of 1500 to 5000.
Is preferably used. The degree of saponification is 70 to 10.
0% is preferable, and 80 to 99.5% is particularly preferable.

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

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 absorbing layer greatly depends on the required ink absorption capacity, the porosity of the second porous layer, the type of the inorganic fine particles, and the type of the water-soluble binder. Is usually 5 to 30 g, preferably 10 to 25 g, per m ² of recording paper.

The ratio of the inorganic fine particles to the water-soluble binder used in the ink absorbing layer is usually from 2: 1 to 2 by mass.
0: 1, particularly preferably 3: 1 to 10: 1.

In the ink jet recording paper of the present invention, a cationic polymer is preferably used for the purpose of preventing bleeding of an image due to storage after recording.

Examples of the cationic polymer include polyethyleneimine, polyallylamine, polyvinylamine,
Dicyandiamide polyalkylene polyamine condensation products, polyalkylene polyamine dicyandiamide ammonium salt condensate, dicyandiamide-formalin condensates, epichlorohydrin-dialkylamine addition polymer, diallyl dimethyl ammonium chloride polymer, diallyl dimethyl ammonium chloride-SO ₂ copolymer, polyvinyl imidazole, Vinylpyrrolidone / vinylimidazole copolymer, polyvinylpyridine, polyamidine, chitosan, cationized starch, vinylbenzyltrimethylammonium chloride polymer, (2-methacryloyloxyethyl) trimethylammonium chloride polymer,
And dimethylaminoethyl methacrylate polymer.

The Chemical Industry Times August 15, 1998
An example is a cationic polymer described on the day, and a polymeric dye fixing agent described in “Introduction to Polymeric Drugs” issued by Sanyo Chemical Industries, Ltd.

In the ink jet recording paper of the present invention, a hardener is preferably used for the purpose of adjusting the physical strength of the ink absorbing layer or for preventing the coating film from cracking at the time of coating and drying.

The hardener is generally a compound having a group that can react with the water-soluble binder or a compound that promotes the reaction between different groups of the water-soluble binder. It is appropriately selected and used depending on the situation.

Specific examples of the hardener include, for example, epoxy hardeners (diglycidyl ethyl ether, ethylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-diglycidylcyclohexane, 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, bisvinylsulfonylmethyl 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 binder, it is preferable to use a hardener selected from boric acid and salts thereof and an epoxy hardener. Most preferred is a hardener selected from boric acid and its salts.

The boric acid or a salt thereof refers to an oxyacid having a boron atom as a central atom and a salt thereof, and specifically, orthoboric acid, diboric acid, metaboric acid, tetraboric acid, pentaboric acid, octanoic acid, and salts thereof. Salt.

The amount of the hardener used varies depending on the type of the water-soluble binder, the type of the hardener, the type of the inorganic fine particles, the ratio to the water-soluble binder, and the like. Is 10-30
0 mg.

Various additives other than those described above can be added to the ink absorbing layer and other optional layers of the ink jet recording paper of the present invention. For example,
Organic latex fine particles such as polystyrene, polyacrylates, polymethacrylates, polyacrylamides, polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, or copolymers thereof, urea resins, or melamine resins, and cations Or various nonionic surfactants described in JP-A-57-74193 and 57
UV absorbers described in JP-A-87988 and JP-A-62-261476; JP-A-57-74192;
No. 989, No. 60-72785, No. 61-14659
No. 1, JP-A-1-95091 and JP-A-3-13376, etc .;
No. 3, No. 59-52689, No. 62-280069
No. 61-242871 and JP-A-4-21926.
No. 6, etc., pH brighteners such as sulfuric acid, phosphoric acid, citric acid, sodium hydroxide, potassium hydroxide, potassium carbonate, defoamers, preservatives, thickeners, antistatic Various known additives such as an agent and a matting agent can also be contained.

The ink absorbing layer may be composed of two or more layers. In this case, the constitutions of the ink absorbing layers may be the same or different.

As the support for use in the present invention, those conventionally known for ink jet recording paper can be used as appropriate, and may be a water-absorbing support, but are preferably a non-water-absorbing support.

Examples of the water-absorbing support which can be used in the present invention include, for example, sheets and plates having ordinary paper, cloth, wood and the like. It is most preferable because it is excellent in cost. As a paper support, chemical pulp such as LBKP and NBKP, GP, CGP, RMP, TMP, CTMP, CM
Those using wood pulp such as mechanical pulp such as P or PGW or waste paper pulp such as DIP as a main raw material can be used. or,
Various fibrous substances such as synthetic pulp, synthetic fiber, inorganic fiber and the like can be appropriately used as a raw material, if necessary.

If necessary, various conventionally known additives such as a sizing agent, a pigment, a paper strength enhancer, a fixing agent, a fluorescent whitening agent, a wet paper strength agent, and a cationizing agent may be contained in the paper support. Can be added.

A paper support is prepared by mixing a fibrous substance such as the above-mentioned wood pulp and various additives with a fourdrinier paper machine, a round paper machine,
It can be manufactured by various paper machines such as a twin wire paper machine. Further, if necessary, the paper may be subjected to size press treatment, starch, polyvinyl alcohol, or the like in the paper making stage or the paper machine, various coating treatments, or calendar treatment.

Non-water-absorbing supports which can be preferably used in the present invention include transparent supports and opaque supports.
Examples of the transparent support include a polyester resin, a diacetate resin, a triacetate resin, an acrylic resin, a polycarbonate resin, a polyvinyl chloride resin, a polyimide resin, a cellophane, a film having a material such as celluloid, and the like. Among them, those having the property of resisting radiant heat when used as OHP are preferable, and polyethylene terephthalate is particularly preferable. The thickness of such a transparent support is preferably 50 to 200 μm.

Examples of the opaque support include resin-coated paper (so-called RC paper) having a polyolefin resin coating layer obtained by adding a white pigment or the like to at least one of the base paper, and white pigment such as barium sulfate added to polyethylene terephthalate. A so-called white pet is preferred.

Prior to the application of the ink absorbing layer, the support is preferably subjected to a corona discharge treatment, an undercoating treatment or the like for the purpose of increasing the adhesive strength between the various supports and the ink absorbing layer. Further, the ink jet recording paper of the present invention does not necessarily need to be colorless, and may be a colored recording sheet.

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

The base paper used for the paper support is made from wood pulp as a main raw 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, LDP,
Any of NDP, LUKP and NUKP can be used, but LBKP, NBSP, LBSP, N
It is preferable to use more DP and LDP. However,
The ratio of LBSP and / or LDP is preferably from 10 to 70% by mass.

As the pulp, a chemical pulp containing less impurities (sulfate pulp or sulfite pulp) is preferably used, and pulp having improved whiteness by 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 the pulp used for papermaking is preferably 200 to 500 ml according to the CSF standard, and the fiber length after beating is 24% by mass of the remaining 24 mesh specified in JIS-P-8207. The sum with the remaining mass% is 30
~ 70% is preferred. The mass% of the remaining 4 mesh is 2
It is preferably 0% by mass or less.

The basis weight of the base paper is preferably 30 to 250 g.
Particularly, 50 to 200 g is preferable. Base paper thickness is 40-2
50 μm is preferred.

The base paper can be calendered at the papermaking stage or after the papermaking to give high smoothness. The base paper density is 0.
7 to 1.2 g / m ² (JIS-P-8118) is common. 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 when measured by the hot water extraction method specified in JIS-P-8113.

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

In particular, the polyethylene layer on the ink absorbing layer side is preferably one in which rutile or anatase type titanium oxide is added to polyethylene to improve the opacity and whiteness as widely used in photographic printing paper. The content of titanium oxide is usually 3 to 20% by mass, preferably 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 coating, so that the matte surface or the silk-like surface can be obtained on ordinary photographic printing paper. Those having a surface can also be used in the present invention.

In the above-mentioned polyethylene-coated paper, it is particularly preferable to maintain the water content in the paper at 3 to 10% by mass.

The first porous layer and the second porous layer of the recording paper of the present invention
A method of applying various ink absorbing layers, which are appropriately provided as necessary, such as a porous layer and an undercoat layer, on a support can be appropriately selected from known methods. A preferred method is obtained by applying a coating solution constituting each layer on a support and drying the coating solution. In this case, two or more layers can be simultaneously coated, and in particular, simultaneous coating in which all the water-soluble binder layers are completed by one coating is preferable.

The coating method is preferably a roll coating method, a rod bar coating method, an air knife coating method, a spray coating method, a curtain coating method, or an extrusion coating method using a hopper described in US Pat. No. 2,681,294. Used.

The recording paper of the present invention has a high possibility of discoloration and fading, and is preferably used in the field of large-format ink jet recording in which a lamination process is usually performed to prevent this. The recording paper is preferably in a roll state, the width is 60 to 180 cm, and the length is 10 to 200 m.
Is preferred.

For the ink jet recording paper of the present invention, the contact time of Bristow measurement of an unrecorded portion was 0.8
The preferable amount of water absorption per ^second is 10 to 30 ml / m ² .

The ink jet recording method of the present invention includes electro-mechanical conversion methods (for example, single cavity type, double cavity type, bender type,
Piston type, shared mode type, shared wall type, etc.), electro-thermal conversion type (eg, thermal ink jet type, bubble jet (registered trademark) type, etc.), electrostatic suction type (eg, electric field control type, slit jet type, etc.) ) And a discharge method (for example, a spark jet type) can be mentioned as specific examples.

The preferred maximum ink ejection amount in the present invention is 10 to 35 ml / m ² .

[0140]

EXAMPLES The present invention will be specifically described below with reference to examples of the present invention, but embodiments of the present invention are not limited to these examples. In the examples, “%” indicates absolute dry mass% unless otherwise specified. (Preparation of Organic Fine Particle Dispersion-1)
The following solution A and solution B were both heated to a liquid temperature of 70 ° C., mixed, immediately emulsified and dispersed by a tabletop homogenizer, and methylene chloride was volatilized under reduced pressure. The solid content concentration of the obtained organic fine particle dispersion liquid 1 was 10%, and the number average particle diameter measured by a laser diffraction / scattering type particle size distribution measurement was 1.2 μm. Solution A Polyvinyl butyral (BL-S manufactured by Sekisui Chemical) 10 parts Methylene chloride 50 parts Solution B Surfactant (Kao Emulgen 220) 0.2 parts Water 100 parts (Preparation of silica-cation polymer dispersion-1) The solution A shown was mixed with the solution B, and the solution C was further mixed, and then mixed with a high-pressure homogenizer (manufactured by Sanwa Kogyo KK).
The dispersion was performed under a pressure of 0 kg / cm ² to obtain a transparent silica-cation polymer dispersion-1. Solution A Gas-phase fumed silica (Nippon Aerosil 300) 125 parts Water 620 parts Nitric acid Add the amount that pH of solution A becomes 2.5 B solution Cationic polymer-1 15 parts Ethanol 40 parts Water 180 parts Nitric acid B solution pH Add the amount that becomes 2.5 Liquid C Boric acid 2.6 parts Sodium tetraborate decahydrate 2 parts Water 70 parts

[0141]

Embedded image

(Preparation of Inkjet Recording Paper-1) A paper support (thickness: 230 μm) coated on both sides with polyethylene
m) A coating liquid-1 having a liquid temperature of 45 ° C. and having the following composition:
After coating and drying with a wire bar, 40 ° C, 80%
It was stored in an RH thermostat for 12 hours to obtain inkjet recording paper-1. The thickness of the dried film was 40 μm.
The ink jet recording paper is hereinafter referred to as a recording paper. Coating liquid-1 Silica-cationic polymer dispersion-1 100 parts Polyvinyl alcohol (Kuraray PVA203) 0.05 parts Polyvinyl alcohol (Kuraray PVA235) 2.2 parts Water 40 parts (Preparation of recording paper-2) Recording paper -1 was coated with organic fine particle dispersion liquid 1 using a wire bar and dried to obtain recording paper-2. The thickness of the layer made of the organic fine particles was 2 μm. (Preparation of Recording Paper-3) The organic fine particle dispersion liquid-1 was coated on the recording paper-1 using a wire bar and dried to obtain a recording paper-3. The thickness of the layer made of organic fine particles was 8 μm. (Preparation of Recording Paper-4) Organic Fine Particle Dispersion-1 was coated on Recording Paper-1 using a wire bar and dried to obtain Recording Paper-4. The thickness of the layer made of organic fine particles is 12 μm
Met. (Preparation of Recording Paper-5) 40 parts of the coating liquid-1 and 60 parts of the organic fine particle dispersion-1 were mixed to prepare a coating liquid-2. The coating liquid-2 was applied onto the recording paper-1 using a wire bar and dried to obtain a recording paper-5. The thickness of the layer containing the organic fine particles was 8 μm. (Preparation of Recording Paper-6) 70 parts of Coating Liquid-1 and 30 parts of Organic Fine Particle Dispersion-1 were mixed to prepare Coating Liquid-3. Coating liquid-3 was applied onto recording paper-1 using a wire bar and dried to obtain recording paper-6. The thickness of the layer containing the organic fine particles was 8 μm. (Preparation of Recording Paper-7) Polyvinyl butyral emulsion (manufactured by Chukyo Yushi, Resem VB J-667, average particle diameter 0.5 μm) on recording paper-1 using a wire bar.
Was applied and dried to obtain recording paper-7. The thickness of the polyvinyl butyral emulsion-containing layer was 2 μm. (Preparation of Recording Paper-8) A urethane emulsion (Superflex E-2500, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., average particle diameter 0.96 μm) was formed on recording paper-1 using a wire bar.
m) was coated and dried to obtain Recording Paper-8. The thickness of the urethane emulsion-containing layer was 2 μm. (Preparation of Recording Paper-9) A styrene- (meth) acrylic emulsion (Polytron E390M, manufactured by Asahi Kasei Kogyo Co., Ltd., average particle diameter: 0.15 μm) was coated on the recording paper-1 using a wire bar, dried, and recorded. Paper-9 was obtained.
The thickness of the styrene- (meth) acrylic emulsion-containing layer was 2 μm. (Preparation of Recording Paper-10) A styrene-butadiene-based tex emulsion (Nipol LX433C, average particle diameter 0.1 μm, manufactured by Zeon Corporation) was coated and dried on recording paper-1 using a wire bar. 10 was obtained. The thickness of the styrene-butadiene-based latex emulsion-containing layer was 2 μm. (Preparation of Recording Paper-11) A polystyrene latex emulsion (average particle diameter: 0.16 μm) was applied to the recording paper-1 using a wire bar and dried.
I got The thickness of the layer containing the polystyrene latex emulsion was 2 μm. (Electron Microscope Observation of Recording Paper) Observation of the surface and cross section of recording paper-1 to -11 with an electron microscope showed that
In each of the recording papers, formation of a void layer due to the particles and the gaps was confirmed on the surface and cross section. (Solubility Test of Organic Fine Particles) The organic fine particles and each emulsion used in the recording papers -2 to -11 were treated with diethylene glycol monobutyl ether (SP value of 19.437).
(MPa) ^1/2 , boiling point 230 ° C.) and mixed at room temperature. As a result, only the polystyrene latex emulsion used for the recording paper-11 was dissolved except that it did not dissolve or swell. On the other hand, glycerin (SP value 33.759 (MPa)
^(1/2 , boiling point 290 ° C.), no organic fine particles were dissolved or swelled. (Preparation of Ink Liquid-1) An ink liquid having the following composition:
1 was produced.

Water 68.5 parts Diethylene glycol monobutyl ether 12 parts Diethylene glycol 10 parts Glycerin 8 parts C.I. I. Direct Blue 86 1 part Surfactant (Shinfin Chemical's Surfynol 465) 0.5 part (Evaluation) The following treatments were applied to recording papers 1 to -11, respectively. Processing 1 Ink liquid-1 is transferred to inkjet printer MJ-800C
(Manufactured by Seiko Epson Corporation)
The solid image was recorded (discharged) on -11. The ink ejection amount was 12 ml / m ² . This image is 23 ℃ ・ 55%
It was dried for 1 hour in an environment of RH. Treatment 2 A 20% aqueous solution of diethylene glycol monobutyl ether was uniformly spray-coated on the surfaces of the recording paper-1 to -11. The coating amount was 20 ml / m ² . This portion was dried under an environment of 23 ° C. and 55% RH for 1 hour. Treatment 3 A 20% aqueous solution of glycerin was spray-coated evenly on the surfaces of the recording paper-1 to -11. 20ml / m
^{Was 2} . This portion was dried under an environment of 23 ° C. and 55% RH for 1 hour. Bristow measurement (measurement of water absorption) The Bristow measurement was carried out on the portions of the recording papers -1 to -11 where the treatments 1, 2 and 3 were performed and on the untreated portion (unit: ml / m ² ). The contact time was 0.8 seconds, and the liquid used was C.I. I. Acid Red 52 is a 0.05% aqueous solution. -Discoloration / fading The recording paper-1 to -11 which has been subjected to the treatment 1 was stuck to a window in an office room, and left for 6 months in an environment exposed to the outside air flow but not exposed to direct sunlight. The reflection density of the printed portion was measured with red monochromatic light, and the ratio before and after standing (residual rate) was determined.

Table 1 shows the results of the above measurements and evaluations.

[0145]

[Table 1]

As is clear from Table 1, recording paper-2 to
-10 is Va / Vb at the time of performing the process 1 (ink application)
Is 0.4 or less, and the discoloration is improved, which indicates that the inkjet recording method of the present invention has an excellent effect. Further, the recording paper-2 to -10 is processed 2
The value of Vc / Vd after application of the aqueous solution was 0.4 or less, indicating that the ink jet recording paper of the present invention also exhibited excellent effects.

In the recording papers -2 to -10, the discoloration is improved by forming a void layer mainly composed of water-insoluble organic fine particles soluble in the water-soluble organic solvent in the ink on the outermost surface. Thus, it can be seen that the inkjet recording method of the present invention has an excellent effect. Further, the recording paper -2 to -10 has an SP value of 9 to 15 and a void layer containing organic fine particles insoluble in water dissolved by a water-soluble organic solvent having a boiling point of 120 ° C or more, Similarly, it can be seen that the ink jet recording paper of the present invention has an excellent effect.

[0148]

According to the present invention, image deterioration such as prevention of browning due to harmful gas can be prevented without any special process for ink jet recording paper having a void type ink absorbing layer having a high ink absorbing speed. It has a remarkably excellent effect that it can be performed.

Claims (9)

[Claims] 1. An ink containing a water-soluble dye, water and a water-soluble organic solvent is applied to an ink-jet recording sheet having a first porous layer having a porous structure as an outermost layer by 10 to 3 times.
An ink jet recording method for discharging at any discharge amount of 5 ml / m ² and drying at room temperature to a constant state, wherein the relationship between the ink jet recording paper and the ink satisfies the following general formula (1). Recording method. The general formula (1) Va / Vb ≦ 0.4 Va is an amount of water transferred at a contact time of 0.8 second when a portion where the ink is applied to the inkjet recording paper at the ejection amount is measured by Bristow, Vb is the amount of water transferred at a contact time of 0.8 seconds when a portion where the ink is not applied to the ink jet recording paper is subjected to Bristow measurement. 2. An SP value of 18.414 to 30.69 (M
Pa) using an ink containing an alcohol-based water-soluble organic solvent, a water-soluble dye, and water having a boiling point of any one of ^1/2 and having a boiling point of 120 ° C. or more, and dissolving or swelling with the alcohol-based water-soluble organic solvent. An ink jet recording method comprising recording on an ink jet recording paper having water-insoluble organic fine particles as a main component and a first porous layer having a porous structure. 3. The water-soluble organic solvent has an SP value of 18.4.
An alcohol-based water-soluble organic solvent having a boiling point of not less than 14 to 30.69 (MPa) ^1/2 and a boiling point of 120 ° C. or more, wherein the main component of the first porous layer is the alcohol-based water-soluble organic solvent 2. The ink jet recording method according to claim 1, wherein the water-insoluble organic fine particles dissolve or swell in water. 4. An ink jet recording sheet having a first porous layer having a porous structure as an outermost layer, and having an SP value of 1
An aqueous solution containing any one of 8.414 to 30.69 (MPa) ^1/2 and containing 10 to 40% by mass of an alcohol-based water-soluble organic solvent having a boiling point of 120 ° C. or more is used as the ink jet recording paper. An ink jet recording paper, characterized in that the ink jet recording paper satisfies the following general formula (2) when 20 ml / m ² is applied to the surface of the ink and dried at room temperature to a constant state. General formula (2) Vc / Vd ≦ 0.4 Vc is the amount of water transfer at a contact time of 0.8 seconds when a portion where the aqueous solution is applied and dried is measured by Bristow, and Vd is the amount of the aqueous solution applied. This is the amount of water transfer at a contact time of 0.8 seconds when a portion not subjected to Bristow measurement is measured. 5. An ink absorbing layer having a first porous layer having a porous structure as an outermost layer, wherein the ink absorbing layer comprises:
It contains water-insoluble organic fine particles having an SP value of 18.414 to 30.69 (MPa) ^1/2 and having a boiling point of 120 ° C. or higher, which dissolves or swells in an alcohol-based water-soluble organic solvent. Characteristic inkjet recording paper. 6. The ink jet recording sheet according to claim 1, wherein the main component of the first porous layer has an SP value of 18.414 to 30.6.
9 (MPa) ^1/2 , and water-insoluble organic fine particles that dissolve or swell in an alcohol-based water-soluble organic solvent having a boiling point of 120 ° C. or higher, and further contain inorganic fine particles and a water-soluble binder as main components. The ink-jet recording sheet according to claim 4, further comprising a second porous layer. 7. An ink absorbing layer having a first porous layer and a second porous layer containing inorganic fine particles and a water-soluble binder as main components, wherein the thickness of the first porous layer is Is 20% or less with respect to the total thickness of the ink absorbing layer, and the thickness of the second porous layer is 80% or more with respect to the total thickness of the ink absorbing layer. The ink-jet recording paper according to any one of items 4 to 6. 8. The water-insoluble organic fine particles having a number average particle size of 0.01 to 1 μm.
8. The ink jet recording paper according to any one of items 7 to 7. 9. The shortest side has a length of 60 cm or more and 10 m.
The inkjet recording paper according to any one of claims 4 to 8, wherein: