JP2002307810A - Ink jet recording medium for pigment ink and method for recording the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet recording medium for a pigment ink having a light resistance, water resistance, small bleeding and high color developing density, excellent pigment fixability and to provide a method for recording the medium. SOLUTION: The ink jet recording medium for the pigment ink comprises a porous ink receiving layer for the pigment ink on the surface of a base. In this medium, the receiving layer contains a pigment and a binding agent, and a mean roughness (Ra) of te surface of the layer according to JIS B 0601 is 0.2 to 2.0 μm.

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 paper for pigment ink having excellent color reproducibility such as color density, lightness and darkness, and color saturation, and excellent pigment fixability, and a recording method therefor.

[0002]

2. Description of the Related Art With the rapid spread of digital cameras and computers, hard copy technology for recording prints and images output from them on paper or the like has rapidly developed. As a result, in terms of color reproducibility, image density, glossiness, weather resistance, etc., quality and performance close to the target silver halide photographs have been obtained. Typical examples of the hard copy recording method include an ink jet method, a sublimation type thermal transfer method, and an electrostatic transfer type method.

[0003] Among them, the ink jet system has advantages such as a relatively small apparatus and low running cost, and is considered to be the mainstream of the hard copy system together with the sublimation type thermal transfer system and the like. In the ink jet method, ink droplets composed of a coloring material and a large amount of a medium are ejected at high speed from a nozzle toward a recording medium. 2. Description of the Related Art Inkjet printers have been rapidly spreading in recent years due to the fact that full color printing and high speed printing are easy and printing noise is low.

[0004] As a coloring material of ink in the ink jet recording system, color reproducibility (Gam) has been known.
Although water-soluble dyes excellent in ut) have been mostly used, such dye inks have disadvantages in terms of fastness including light fastness and water fastness. Because of this,
It has been proposed to use a pigment ink in which the coloring material is a pigment, and it is already becoming popular. With pigment inks, the above problems of light resistance and water resistance, which were problems with conventional dye inks, are solved, and the bleeding seen when printing on recording paper using dye inks is significantly improved. You.

[0005] Furthermore, pigment ink is basically the same color material as ink used in plate-making printing such as offset printing and gravure printing, and as a result of approximation of the color hue, test printing for color proofing in these plate-making printing. It has characteristics that can be used as a so-called color proof.

However, when a pigment ink is used, when it is printed on a recording medium such as paper used for a conventional dye ink, the color reproducibility such as color density, lightness / darkness, and color saturation is insufficient. In addition, there has been a problem that the ink is easily peeled off when the printing portion or the image portion is rubbed after printing. Pigment ink, unlike dye ink in which the dye is dissolved in water, has fine water-insoluble pigment particles dispersed in a medium such as water. There is also a problem that abnormal ejection due to an increase in ink viscosity in the vicinity or nozzle clogging is likely to occur in the worst case.

In recent years, means for solving the problems in ink jet printing using these pigment inks have been proposed, and are disclosed in JP-A-11-78225 and JP-A-10-78225.
JP-A-119422, JP-A-10-166717, JP-A-9-123593 and the like can be seen. Among them, for example, in Japanese Patent Application Laid-Open No. 11-78225,
As an inkjet recording medium for improving the fixation of pigment ink, it has been proposed to provide an ink receiving layer on a paper base material and further provide a pigment fixing layer having specific physical properties. As a result, the production becomes complicated and the cost increases.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an ink jet recording medium having an ink receiving layer on the surface of a base material, which is advantageous when a pigment ink such as light fastness, water fastness and small bleeding is used. With excellent color reproducibility such as color density, lightness and darkness, color saturation, etc., and with sufficient fixability of the pigment ink in the ink receiving layer, the ink jet for pigment inks is maintained while maintaining the image quality and without providing a special pigment fixing layer. It is an object of the present invention to provide a recording medium paper and an ink jet recording method using the recording medium.

[0009]

The inventor of the present invention has conducted various studies to achieve the above-mentioned object. As a result, the ink jet printing using the pigment ink and the ink jet printing using the conventional dye ink were respectively carried out. It has been found that since the properties and characteristics of the inks are different, the recording media required for them are required to have almost completely different characteristics. That is, FIGS. 1 and 2 show the respective color materials (S) in the case of the dye ink and the case of the pigment ink in the case where the ink-jet printing is performed using the recording media having different surface properties of the ink receiving layer. FIG. 3 is an enlarged cross-sectional view of a recording medium schematically showing behavior.

A recording medium (A) having an ink receiving layer having a rough surface property, a recording medium (B) having an ink receiving layer having a medium surface roughness, and a recording medium (C) having an ink receiving layer having a smooth surface are provided. In the case of inkjet printing using the three types of recording media of (1) and (2), in the inkjet printing using the conventional dye ink of FIG.
Is dissolved in a medium such as water constituting the ink, and penetrates into the recording medium together with the ink medium at the time of printing, and is deposited on the surface or the surface layer of the ink receiving layer (I) of the recording medium. I do.

As a result, the printing quality and image quality of ink jet printing using dye ink are low when the surface of the ink receiving layer such as the recording medium (A) is extremely rough, and the initial density is low and the gloss is low. Further, when the recording medium (B) has a medium roughness such as that of the recording medium (B), the coloring density is moderate and the glossiness is moderate. On the contrary,
When the recording medium (C) has an ink receiving layer having high smoothness, the coloring density is high and the glossiness is high.
Excellent printing and image quality can be obtained.

On the other hand, in the case of ink-jet printing using a pigment ink, the coloring material (S) composed of a pigment is in a dispersed state as fine particles without being dissolved in an ink medium. Although the medium permeates into the recording medium, the coloring material adheres to the surface of the ink receiving layer (I) of the recording medium or in the vicinity thereof without penetrating into the recording medium.

In such a case, when the smoothness of the surface of the ink receiving layer is large as in the case of the recording medium (C), there is no so-called anchor effect, so that the pigment particles of the coloring material only adhere to the surface of the recording medium. And sufficient fixability is not obtained, and the toner is removed by a little friction. Further, the obtained image may have metallic luster and cause a so-called bronzing phenomenon. On the other hand, when the surface of the ink receiving layer is rough as in the recording medium (A), the pigment particles of the coloring material are buried in the rough surface of the ink receiving layer, and as a result, only a part of the pigment ink particles comes out on the surface. Color density is reduced. Thus, in the case of inkjet printing of a pigment ink, when the ink receiving layer such as the recording medium (B) has a moderate moderate surface roughness, the pigment particles are appropriately fixed on the surface, and as a result, the color density Is sufficient, and hard-to-remove quality is obtained by friction.

The present invention has been made as a result of combining the above findings with the surface characteristics of the ink receiving layer of the recording medium, and has the following configuration. (1) An ink jet recording medium having a porous ink receiving layer for a pigment ink on a surface of a substrate, wherein the ink receiving layer contains a pigment and a binder, and JIS of the surface thereof
The average roughness (Ra) is 0.2 to 2.0 μm according to B0601.
m, an inkjet recording medium for pigment ink. (2) The ink jet recording medium for a pigment ink according to the above (1), wherein the ink receiving layer has a thickness of 5 to 100 µm and the average particle diameter of the pigment contained therein is 1 µm or less. (3) The ink receiving layer has an average pore radius of 3 to 25 n.
m. The inkjet recording medium for a pigment ink according to the above (1) or (2), which has a pore volume of 0.3 to 2.0 cm ³ / g. (4) The inkjet recording medium for a pigment ink according to the above (1), (2) or (3), wherein the pigment in the ink receiving layer is an alumina hydrate. (5) The pigment ink has a color pigment having an acid value of 50 to 280 mg.
-KOH / g, a microencapsulated ink in which microcapsules covered with a film-forming resin in which a part of acid groups have been neutralized and encapsulated are dispersed in an aqueous medium.
The inkjet recording medium for a pigment ink according to any one of (4). (6) The surface of the base material contains a pigment and a binder, and the surface has an average roughness (Ra) of 0.2 to JIS B0601.
An inkjet recording method using a pigment ink, wherein the pigment ink is inkjet-printed on an inkjet recording medium having a porous ink receiving layer of 2.0 μm. Hereinafter, the present invention will be described in more detail.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The ink jet recording medium of the present invention comprises a substrate preferably having a sheet shape and an ink receiving layer formed thereon. Although the material of the base material is not particularly limited, paper, plastic, ceramic, metal, and the like can be used, but a paper base material mainly composed of pulp is preferably used. As a paper substrate,
The pulp is preferably 70% by mass or more, particularly 80% by mass.
Those containing not less than mass% are appropriate. Preferably, acidic paper, neutral paper, or coated paper which has ink absorbency and is used in the coated paper field can be used.

As the pulp constituting the paper base material, natural pulp mainly composed of softwood pulp, hardwood pulp, or mixed pulp of softwood and hardwood is preferably used. They are preferably used in bleached pulp such as kraft pulp, sulfite pulp and soda pulp.
Further, in addition to natural pulp, a paper substrate containing synthetic fibers or synthetic pulp can be used.

The thickness of the substrate is selected according to the application.
However, as a basis weight, 60 to 250 g / m ^TwoPrefer to be
In particular, 100 to 230 g / m^TwoIs preferred. the above
Various additives such as fillers, sizing agents, paper strength
May contain enhancers, pH adjusters, yield improvers, etc.
it can.

The surface properties of the substrate are not particularly limited, but in some cases affect the properties of the ink-receiving layer formed thereon, so that the specific smoothness and the specific Stexigt size are determined. It is preferable to have a degree. That is, those having an Oken type smoothness of 30 to 500 seconds and a Steckigt sizing degree of 30 to 2000 seconds are preferable. If the Oken type smoothness of the substrate surface is less than 30 seconds,
The smoothness of the surface of the ink receiving layer tends to decrease. On the other hand, if the Oken type smoothness exceeds 2000 seconds, the smoothness of the surface of the ink receiving layer tends to increase. On the other hand, when the Stigecht sizing degree is smaller than 30 seconds, the smoothness of the surface of the ink receiving layer tends to decrease. On the other hand, if the Stekigt sizing degree exceeds 2000 seconds, the smoothness of the surface of the ink receiving layer tends to increase. Among them, Oken type smoothness is 30 ~
It is preferred that the Stöckigt sizing degree is 30 to 1000 seconds at 150 seconds.

In the present invention, the porous ink receiving layer formed on the base material comprises a layer containing a pigment and a binder.
It is necessary that the surface has an average roughness according to JIS B0601 and Ra of 0.2 to 2.0 μm. Average roughness in this case, in the measurement method described in JIS B0601, the arithmetic mean roughness cut-off value (lambda _c) is 0.8 mm, evaluation length (l _n) is measured at 4 mm. As described above, the average roughness is 0.2 μm
When the particle size is smaller than the above range, sufficient fixability of the pigment particles of the coloring material cannot be obtained, the toner particles are removed by a little friction, and a bronzing phenomenon occurs. On the other hand, the average roughness is 2.0 μm
In the case where the ratio exceeds 1, only the pigment particles of the coloring material come out on the surface, so that the coloring density decreases. Within the above range, it was found that particularly preferable characteristics were obtained when the average roughness was particularly 0.3 to 1.0 μm.

In order to make the surface roughness of the ink receiving layer fall within the above range, the particle size and amount of the pigment and the binder forming the ink receiving layer, the method of applying the ink receiving layer, Can be performed by various means such as a smoothing process. Among them, it is preferable to control the average particle diameter of the pigment forming the ink receiving layer and to treat the surface of the pigment with a roll having an appropriate surface roughness after the formation of the ink receiving layer.

As the pigment for forming the porous ink receiving layer, various pigments can be used. However, the average particle diameter is preferably 1 due to the necessity of controlling the surface roughness as described above.
It is preferred that it is not more than μm. Average particle diameter is 1μm
When the value exceeds, the surface roughness of the ink receiving layer becomes large, and it becomes difficult to control the surface roughness within the above range.
Among them, the average particle diameter of the pigment is preferably 0.05 to 0.5 μm. Here, the average particle diameter is a value obtained by a laser scattering method.

Various pigments can be used as the pigment for forming the ink receiving layer. For example, colloidal silica,
Alumina, alumina hydrate, synthetic particulate silica, synthetic particulate alumina silicate, vapor-phase synthetic silica, zeolite, montmorillonite group mineral, beiderite group mineral, saponite group mineral, hectorite group mineral, stevensite group mineral, hydrotalcite group Minerals, smectite minerals, bentonite minerals, calcium carbonate, magnesium carbonate, calcium sulfate, barium sulfate, titanium oxide, titanium sol, zinc oxide, zinc carbonate, aluminum silicate, calcium silicate, magnesium silicate, kaolin, talc, aluminum oxide, water Examples include aluminum oxide, a polyaluminum hydroxide compound, plastic pigment, urea resin pigment, cellulose particles, starch particles, and the like. Above all, alumina hydrate is preferable, and boehmite (Al ₂ O _{3
· NH 2 O, n = 1~1.5} ) are preferred.

Examples of the binder forming the ink receiving layer include gelatin, starch or a modified product thereof, polyvinyl alcohol or a modified product thereof, polyvinylpyrrolidone, styrene-butadiene rubber latex,
Nitrile-butadiene rubber latex, water-soluble polymers such as methylcellulose, carboxymethylcellulose, hydroxycellulose, hydroxymethylcellulose, polyacrylic acid, polyacrylamide, alcohol-soluble polymers, and mixtures of these polymers can be used. Among them, in the present invention, use of polyvinyl alcohol or a modified product thereof is preferable because of good ink absorbency and water resistance. The binder is preferably contained in an amount of preferably 1 to 30 parts by mass, particularly preferably 3 to 15 parts by mass with respect to 100 parts by mass of the pigment in the ink receiving layer.

Means for providing an ink receiving layer on the surface of a substrate include, for example, a slurry prepared by adding a binder to a pigment, a roll coater, an air knife coater, a blade coater, a rod coater, a bar coater, a comma coater,
Gravure coater, die coater, curtain coater,
A method of applying and drying using a spray coater, a slide die coater or the like can be adopted.

The ink-receiving layer thus formed in the present invention has sufficient ink absorbency and transparency, and therefore has an average pore radius of 3 for its pore structure.
２５25 nm and a pore volume of 0.3-2.0 cm ³ /
g is preferred. In the case of having such pore characteristics, excellent printing and images can be obtained by increasing the absorbency of the ink receiving layer for the medium in the pigment ink. Among them, the average pore radius is 6 to 20 nm,
A pore volume of 0.5 to 1.5 cm ³ / g is particularly preferred. The pore radius of the ink receiving layer preferably has the above average pore radius and is substantially distributed in the range of 1 to 50 nm. The pore radius distribution in the present invention is measured by a nitrogen adsorption / desorption method.

The thickness of the ink receiving layer is appropriately selected depending on the type of printer used.
0 μm is preferred. When the thickness is smaller than the above range, the solvent in the ink may not be sufficiently absorbed.
On the other hand, if the thickness is larger than the above range, transparency may be impaired, or the strength of the ink receiving layer may be reduced. Above all, the thickness of the ink receiving layer is 10 to 5
0 μm is preferred.

The ink jet recording medium of the present invention can be subjected to various processes as required. For example, by performing a smoothing process such as a calendar process, the surface roughness of the ink receiving layer can be controlled at this stage. Further, the surface of the ink receiving layer of the recording medium,
A surface layer containing colloidal silica or the like can be provided to protect the ink receiving layer, or an appropriate intermediate layer can be provided between the substrate and the ink receiving layer. In these cases, especially when a surface layer is provided, it is necessary to make the surface roughness fall within the range of the present invention, and the thickness and the particle size used for the surface layer are controlled. Further, by providing various back coating layers on the surface of the substrate opposite to the surface having the ink receiving layer, it is possible to prevent curling and improve paper transportability.

In the case of ink-jet printing on the recording paper of the present invention, as the pigment ink, a resin-soluble pigment ink or pigment obtained by dispersing a water-soluble resin and a pigment as a dispersant in an aqueous medium such as water is used. Any microencapsulated pigment ink in which microcapsules covered with a film-forming resin and contained therein are dispersed in an aqueous medium such as water can be used. Among them, the use of the latter microencapsulated pigment ink is particularly preferred in the present invention. The reason is that the ink has excellent dispersion stability, and when the pigment ink is jetted onto a recording medium, the pigment is coated with a resin, so a resin film is formed on the surface of the pigment particles, and high gloss printing is performed. And an image can be obtained. The pigment in the pigment ink is contained in the ink in an amount of 0.5 to 20% by mass, in particular, 2 to 1% by mass.
Those containing 2% by mass are preferred. For pigment ink,
If necessary, a dispersant, an antioxidant, a viscosity modifier and the like are further added.

As the pigment contained in the pigment ink,
Various inorganic or organic pigments can be used. Examples of inorganic pigments include oxide pigments such as titanium oxide, cadmium oxide, iron oxide, chromic acid, and silicate, pigments such as sulfide pigments, carbonate pigments, metal complex pigments, and carbon black. Can be exemplified. Examples of the organic pigment include azo, anthraquinone, phthalocyanine, quinacridone, isoindoline, dioxazine, perinone, perylene, isodigo, quinophthalone, and diketopyrrolopyrrole pigments.

The microencapsulated pigment ink preferably used in the present invention has an acid value of preferably 50.
Self-water-dispersible resin pigment particles having an average particle diameter of 1 to 280 mg-KOH / g, wherein 60 mol% or more of the acid groups are neutralized with a base such as alcoholamine.
A pigment ink containing the above pigment particles having a size of 0 to 100 nm is preferable. As the self-water dispersible resin in this case, a styrene resin, an acrylic resin, a polyester resin, a polyurethane resin, or the like is used.

In the present invention, the method of ink-jet printing using the pigment ink on the above-mentioned ink-jet recording medium is not particularly limited, and a full-color ink jet printer or a thermal ink-jet printer can be used. Print or image can be obtained.

[0032]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but it is needless to say that the present invention is not limited to these examples. Examples 1 to 3 are examples of the present invention, and Examples 4 and 5 are comparative examples. Also,
“Parts” in the examples indicate parts by mass unless otherwise specified.

Example 1 Hardwood bleached kraft pulp 85
And 15 parts of softwood bleached kraft pulp
After beaten to 20 CSF (Canadian standard freeness), 15 parts of light calcium carbonate, 1.0 part of cationic starch, and 0.1 part of alkenyl succinic anhydride-based neutral sizing agent were added thereto. A stock slurry was prepared by thorough mixing.

Next, the above stock slurry was paper-made using a fourdrinier paper machine, and then a 5% aqueous solution of oxidized starch was applied to both sides thereof with a size press at 5 g / m ² , followed by drying. By drying to 7%, basis weight 157g
/ M ² high quality paper was produced. The fine paper had an Oken-type smoothness of 60 seconds and a Steckigt sizing degree of 70 seconds.

On one surface of this high-quality paper, the following ink-receiving layer formulation 1 was applied using a bar coater so that the coating layer after drying had a thickness of 20 μm.
It dried at ℃, and manufactured the inkjet recording paper. The alumina sol used in the following ink-receiving layer formulation 1 was prepared by adding a sodium aluminate solution to a liquid consisting of polyaluminum chloride and water heated to 95 ° C., washing the aged slurry with ion-exchanged water, Temperature to ℃
Acetic acid was added for peptization and concentration, followed by ultrasonic treatment to obtain an alumina sol.

Ink receiving layer formulation 1: alumina sol (alumina sol produced as described above, average particle size 0.2
μm): 100 parts, polyvinyl alcohol (trade name: PA-124, manufactured by Kuraray Co., Ltd.): 10 parts. With respect to the recording paper thus obtained, the average roughness, Ra, of the surface of the ink receiving layer was 0.56 μm. The ink receiving layer had a pore volume of 0.69 cm ³ / g and an average pore radius of 9.8 nm.

Example 2 The surface of the ink receiving layer of the ink jet recording paper obtained in Example 1 was subjected to a super calendar treatment (line speed 5 m / min, roll temperature 20 ° C.) by a mini super calendar (manufactured by Yuri Roll Machine Co., Ltd.). Nip pressure of 50 kN / m) to make the average roughness of the surface of the ink receiving layer 0.34 μm.

Example 3 The following coating layer formulation 1 was used on the surface of the ink receiving layer of the ink jet recording medium obtained in Example 1 so that the thickness of the coating layer after drying was 1 μm. By coating and drying in the same manner as in Example 1,
An ink jet recording paper having an ink receiving layer provided with a protective coating layer on the surface was produced. Coating layer formulation 1: Colloidal silica (catalyst Kasei Co., trade name: Cataloid S1-45P, average particle diameter 45 nm):
100 parts, colloidal silica composite polymer (manufactured by Clariant Polymer Co., Ltd., trade name: Mobile 8050): 100
Department. With respect to the recording medium thus obtained, the average roughness, Ra, of the surface of the ink receiving layer was 0.44 μm.

Example 4 In the same manner as in Example 1, except that the following ink receiving layer formulation 2 was used instead of the ink receiving layer formulation 1 so that the thickness of the coating layer after drying was 20 μm. By carrying out, an ink jet recording paper was manufactured. Ink receiving layer formulation 2: amorphous silica (trade name: P78A, manufactured by Mizusawa Chemical Co., Ltd., average particle diameter: 3.3 μm): 100
Part, polyvinyl alcohol (Kuraray Co., trade name: R-
1130): 40 parts. With respect to the obtained recording paper, the surface roughness and Ra of the ink receiving layer were 3.54 μm, and the ink receiving layer had a pore volume of 1.08 cm ³ / g and an average pore radius of 8.5.
nm.

Example 5 A mixture of 70 parts of low-density polyethylene resin, 20 parts of high-density polyethylene resin and 10 parts of titanium oxide was applied to the front side of the same high-quality paper used in Example 1, and the back side was used. A sheet obtained by applying a mixture consisting of 50 parts of a low-density polyethylene resin and 50 parts of a high-density polyethylene resin by melt extrusion coating so that the coating amount is 20 g / m ² , An ink receiving layer formulation 1 was applied to the surface of the coating layer of a mixture of high-density polyethylene resin and titanium oxide in the same manner as in Example 1 to produce an ink jet recording medium having an ink receiving layer on the surface.

In the above recording medium, the surface of the coating layer of the mixture of high-density polyethylene resin and titanium oxide on the front side of the base material before coating the ink receiving layer has an Oken type smoothness of 10%.
Although the time was 00 seconds, the degree of Stigecht sizing could not be measured because the measurement solution did not penetrate. The average roughness of the surface of the ink receiving layer of the recording medium was 0.10 μm.

For the five types of ink jet recording papers of Examples 1 to 5, an ink jet printer for pigment ink (MC-2000, manufactured by Seiko Epson Corporation)
And MC1 which is a microencapsulated pigment ink for the inkjet printer as a pigment ink.
Inkjet printing was performed using BK01 (black) and MC5CL01 (color), and the resulting recorded matter was evaluated for color density, ink fixability, ink absorption, and bronzing phenomenon. Table 1 shows the evaluation results.

[Oken Type Smoothness] JAPAN TAPPI
Paper pulp test method NO. It measured according to 5B. [Degree of Stigecht size] It was measured according to JIS P8122. [Coloring density] Black, cyan, yellow, and magenta solid printing was performed, and the respective saturated reflection color densities were measured. [Ink fixability] Solid printing of gradations of black, cyan, yellow and magenta was performed. As an ink peeling test, the printed portion was rubbed with a nail and visually evaluated according to the following criteria. ：: The ink hardly peeled off. Δ: Ink slightly peeled off. ×: The ink was remarkably peeled. Table 1 shows the evaluation results. [Ink Absorption] Solid black, cyan, yellow and magenta gradation printing was performed. The graininess due to poor ink absorbency in the solid printed area was visually evaluated based on the following criteria. ：: No granular feeling. Δ: There is some graininess, but there is no practical problem. X: Graininess is remarkable and there is no practicality. [Bronzing] Solid printing of gradations of black, cyan, yellow and magenta was performed. The bronzing phenomenon on the surface of the solid printed portion was visually evaluated. ：: No bronzing phenomenon was observed. X: Bronzing phenomenon is observed.

[0044]

[Table 1] As shown in Table 1, it can be seen that the ink jet recording paper of the present invention is superior in color density, ink absorbency and ink fixability to pigment ink.

[0045]

According to the present invention, while maintaining the advantages of using a pigment ink such as light fastness, water fastness and small bleeding, and without providing a special pigment fixing layer,
Provided are an ink jet recording paper for a pigment ink having a high coloring density and sufficient fixability of the pigment ink in an ink receiving layer, and a recording method using the ink jet recording paper for a pigment ink.

[Brief description of the drawings]

FIG. 1 is an enlarged cross-sectional view schematically showing the behavior of each color material (S) when inkjet printing is performed on three types of recording media having different surface properties of an ink receiving layer using a conventional dye ink. FIG.

FIG. 2 is an enlarged view schematically showing the behavior of each color material (S) when inkjet printing is performed on three types of recording media having different surface properties of an ink receiving layer using the pigment ink of the present invention. Sectional view.

[Explanation of symbols]

A: Recording medium having an ink receiving layer with a rough surface property B: Recording medium having an ink receiving layer with a medium surface roughness C: Recording medium having an ink receiving layer with a smooth surface K: Base material I: Ink Receiving layer S: coloring material in ink consisting of dye or pigment

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 2C056 FC06 2H086 BA15 BA33 BA34 BA35 BA41 BA44 BA45 BA55 BA60

Claims (6)

[Claims] An ink jet recording medium having a porous ink receiving layer for a pigment ink on a surface of a substrate, wherein the ink receiving layer contains a pigment and a binder, and has an average roughness (JIS B0601) of the surface thereof according to JISB0601. Ra) is 0.2-
An inkjet recording medium for pigment ink, which has a thickness of 2.0 μm. 2. The ink receiving layer according to claim 1, wherein said ink receiving layer has a thickness of 5 to 100 μm.
m and the average particle diameter of the pigment contained therein is 1 μm.
The inkjet recording medium for a pigment ink according to claim 1, which is not more than m. 3. The ink receiving layer according to claim 2, wherein the average pore radius is 3 to 2
The inkjet recording medium for a pigment ink according to claim 1, having a thickness of 5 nm and a pore volume of 0.3 to 2.0 cm ³ / g. 4. The ink jet recording medium for a pigment ink according to claim 1, wherein the pigment in the ink receiving layer is alumina hydrate. 5. A pigment ink comprising a color pigment having an acid value of 50 to 28.
5. A microencapsulated ink comprising 0 mg-KOH / g, coated with a film-forming resin in which a part of acid groups has been neutralized, and encapsulating microcapsules dispersed in an aqueous medium. The inkjet recording medium for a pigment ink according to any one of the above. 6. Ink jet recording having a porous ink receiving layer on a surface of a base material containing a pigment and a binder and having an average roughness (Ra) of 0.2 to 2.0 μm according to JIS B0601 on the surface. An ink jet recording method using a pigment ink, wherein the pigment ink is ink-jet printed on a medium.