JP2000168228A - Ink jet recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make an ink jet recording medium have fretting and fixing properties to be counted for notching practically even when pigment ink is used and to permit common use thereof with dye ink, by a method wherein two ink receiving layers are provided on one surface and the ink receiving layer constituted mainly of a water-soluble resin and containing a specified amount of inorganic particulates having a specified average particle size is provided on the side distant from a substrate. SOLUTION: Cationically modified polyvinyl alcohol(PVA) of 100 pts. and silica particulates of 0.7 pts. in a solid content are dissolved in water and mixed. A coating solution thus obtained is applied on a polyethylene terephthalate film (100 μm thick) so that the thickness after drying be 7 μm, and it is dried to obtain an ink receiving layer. Moreover, a composition constituted of the cationically modified PVA 100 pts. and colloidal silica particulates (of an average particle size 10-20 nm) 25 pts. in the solid content is dissolved and mixed, with water used as a medium. A coating solution thus obtained is applied on the preceding ink receiving layer so that the thickness after drying be 3 μm, and then it is dried to obtain an ink receiving layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a recording medium suitably used for ink jet recording. In particular, it relates to an ink jet recording medium using a pigment ink.

[0002]

2. Description of the Related Art In recent years, ink jet printers have rapidly become widespread due to features such as quietness, cost, and ease of full-color printing. In addition, a recording medium for an ink jet printer is required to quickly absorb ink and have excellent color development.

As inks for ink jet recording, those using water as a main component and aqueous dyes have been the mainstream, but pigment inks have recently attracted attention in terms of storage stability and weather resistance after recording. Since pigments are insoluble in water, pigment inks in the form of fine particles dispersed in water are known.

[0004]

However, when recording is performed on a conventional dye ink recording medium using a pigment ink, the pigment particles form a film on the surface without entering the ink receiving layer. When inorganic fine particles are used, the rubbing property is poor and the utility is poor, and when the main component of the ink receiving layer is a water-soluble resin, the rubbing property is satisfactory but the swelling of the ink receiving layer causes the pigment film to crack on the surface. There was a problem. Further, when a resin having a small amount of swelling is used for the ink receiving layer, the pigment film does not crack, but the ink absorption is poor, so that the ink cannot be used in common with the dye ink, and the drying time becomes longer, which causes a problem in actual use. Was.

Japanese Patent Application Laid-Open No. 9-123593 proposes that a water-soluble resin layer is provided on a porous layer of alumina hydrate in order to achieve both fixing property and ink absorption of a pigment ink. The pores of the alumina hydrate porous layer are blocked by the water-soluble resin layer, so that the transfer of water from the water-soluble resin layer to the alumina hydrate porous layer is slowed down, and a sufficient ink absorption rate is obtained. The ink overflows on the surface without being cleaned.

Further, Japanese Patent Application Laid-Open No. Hei 7-186521 proposes a constitution in which a hydrophilic resin and inorganic fine particles are provided on a water-soluble resin layer. However, since the hydrophilic resin is insoluble in water, pigment particles cannot be fixed. It could not be used due to poor abrasion.

[0007] Therefore, an object of the present invention is to use a pigment ink, which has no scratches in the printed portion, has practically no problem, and has abrasion and fixing properties (ink drying time). The present invention provides a possible ink jet recording medium.

[0008]

The above object is achieved by
The following is achieved by the present invention. That is, the present invention provides an ink jet recording medium having two ink receiving layers on at least one surface of a support, wherein the content of inorganic fine particles having a water-soluble resin as a main component and an average particle diameter of 50 nm or more and 1 μm or less is 10 wt. % To 30 wt%, preferably 20 to 30 wt. % Of the ink receiving layer (a) provided on the side far from the support, and less than 10 wt% (or 0 wt.%) Of the inorganic fine particles and the water-soluble resin on the side near the support. Can be achieved by an ink jet recording medium provided thicker than the ink receiving layer (a).

That is, the pigment particles are fixed by the water-soluble resin, and the swelling due to the water and the solvent contained in the pigment ink is suppressed by the inorganic fine particles. Furthermore, since the two layers use a water-soluble resin, the movement of water is performed quickly, and the ink receiving layer made of the ink-absorbing resin on the lower side can sufficiently absorb the water and the solvent contained in the pigment ink. The drying time is not long. Further, even if the dye ink is used, an image having no problem can be obtained.

When the content of the inorganic fine particles having an average particle diameter of 1 μm or less in the ink receiving layer (a) of the present invention is less than 10 wt%, the pigment coating is broken on the surface by swelling of the ink receiving layer when a pigment ink is used. I will. When the amount exceeds 30 wt%, the fixation of the pigment particles is not only deteriorated, but also when the dye ink is used, the ink absorption is deteriorated, and the image is deteriorated due to the overflow of the ink in the portion where the amount of the dye ink is applied, and the ink is deteriorated. The drying property also deteriorates. Further, the water-soluble resin dissolves in the aqueous ink at room temperature to secure the fixability of the pigment particle film. The average particle diameter of the inorganic fine particles is 1 μm in order to form the ink receiving layer (a) uniformly and thinly.
The thickness is preferably 50 nm or more, and more preferably 100 nm or less if transparency is required, such as an OHP sheet. The ink receiving layer (b) made of less than 10 wt% of the inorganic fine particles (may be 0 wt.%) And a water-soluble resin is more excellent in ink absorbency than the ink receiving layer (a), so that the ink receiving layer (a) By quickly absorbing the absorbed ink or water and solvent, image deterioration due to overflow of the ink is prevented in a portion where the amount of applied ink is large, and the ink drying property is improved. Therefore, when the ink receiving layer (a) is thickened, it takes time for the ink or the water and the solvent to move to the ink receiving layer (b), so that the image is deteriorated due to the overflow of the ink in the portion where the amount of the dye ink applied is large. Therefore, it is preferable that the ink receiving layer (a) is thin and the ink receiving layer (b) is thick. The thickness of the ink receiving layer (a) is preferably 5 μm or less and 2 μm or more. Also,
The layers (a) and (b) preferably have a range of 3 ≧ (b) / (a)> 1.

The inorganic fine particles used in the present invention include silica, alumina, aluminum silicate, magnesium silicate, basic magnesium carbonate, talc, clay, hydrotalcite, calcium carbonate, titanium oxide, and zinc oxide. And the like, but are not limited to these. For transparency and uniformity of the ink receiving layer, colloidal silica and alumina hydrate are more preferable. In addition, when the highly water-absorbent resin particles are used as the fine particles, the resin particles themselves absorb the ink and swell. As a result, the pigment film is broken.

Here, the water-soluble resin of the present invention is not particularly limited, but is not limited as long as it can accept a so-called aqueous ink and shows solubility in the aqueous ink. Synthetic resins such as alcohol, anion-modified polyvinyl alcohol, force thione-modified polyvinyl alcohol, polyurethane, carboxymethyl cellulose, polyester, polyacrylic acid (ester), polyacrylamide, hydroxyethyl cellulose, hydroxypropyl cellulose, melamine resin, and modified products thereof; Further, water-soluble resins such as albumin, gelatin, casein, starch, cationized starch, natural resins such as gum arabic and sodium alginate can be exemplified, but are not limited thereto. Among these, cation-modified polyvinyl alcohol was preferred in view of image quality and water absorption.

In the present invention, a plurality of water-dispersible resins may be used simultaneously in addition to the water-soluble resin. A water-dispersible resin may be used as the binder layer, for example, polyvinyl acetate, ethylene-vinyl acetate copolymer, polystyrene, styrene- (meth) acrylate copolymer, (meth) acrylate-based polymer , Vinyl acetate- (meth) acrylic acid (ester) copolymer, poly (meth) acrylamide, (meth) acrylamide copolymer, styrene-isoprene copolymer, styrene-butadiene copolymer, ethylene-propylene copolymer A large number of rows such as coalescing and polyvinyl ether can be cited, but are not limited to these.

Further, in order to improve image preservability,
(A) layer and / or 1 to 10 wt. % Of a cationic compound.

The cationic compound is not particularly limited as long as it contains a cationic moiety in the molecule. For example, a quaternary ammonium salt type cationic surfactant such as monoalkylammonium chloride, dialkylammonium chloride, and ethylene oxide-added ammonium chloride, or an amine salt type cationic surfactant, and further contains a cationic portion An amphoteric surfactant such as an alkyl betaine, imidazomium, or alanine may be used. As the polymer or oligomer, cationically modified polyacrylamide or a copolymer of acrylamide and a cationic monomer, polyethylenimine, polyamide-epichlorohydrin resin, polyvinylpyridinium halide, various polyamine-based resins, for example, polyallylamine, polyamine sulfone, Polyvinylamine and the like. Further, a vinylpyrrolidone monomer alone or a copolymer with another general monomer, a vinyloxazolidone monomer alone or a copolymer with another general monomer,
Vinylimidazole monomer alone or other
Copolymers with general monomers are exemplified. Common monomers include methacrylate, acrylate, acrylonitrile, vinyl ether, vinyl acetate,
Examples include ethylene and styrene.

In the present invention, a recording medium having an ink-receiving layer on the surface of a substrate is used. However, various additives may be mixed with this composition as long as the object of the present invention is not hindered. Specific examples of additives include various surfactants, dye fixing agents (waterproofing agents), defoamers, antioxidants,
Fluorescent whitening agent, UV absorber, dispersant, viscosity modifier, pH
Modifiers, fungicides, and plasticizers are included. These additives may be arbitrarily selected from conventionally known compounds according to the purpose.

The base material constituting the recording medium of the present invention includes fine paper, medium paper, art paper, glossy paper, bond paper, recycled paper, baryta paper, cast coated paper, corrugated paper,
Non-wood paper, paper such as synthetic paper, film made of plastic such as polyethylene terephthalate, diacetate, triacetate, cellophane, celluloid, polycarbonate, polyimide, polyvinyl chloride, polyvinylidene chloride, polyacrylate, polyethylene, polypropylene, veneer, cypress , Wood or board such as cedar, glass board, ceramics, metal plate such as aluminum, iron, steel or cotton, rayon, acryle, nylon,
Cloth such as silk and polyester, leather such as cow, sheep and crocodile, human leather, non-woven fabric, rubber-like elastic material, inorganic paper and the like can be used. The surface of the base material may be a smooth surface, a surface with irregularities, and may be transparent, translucent, or opaque. Further, two or more of these substrates may be bonded to each other. Further, a mat layer, a peelable adhesive layer or the like may be provided on the opposite side of the printing surface, or an adhesive layer or the like may be provided on the printing surface after printing. The substrate is appropriately selected from the above-mentioned substrates according to various conditions such as the recording purpose of the recording medium, the use of the recorded image, and the adhesion to the composition coated on the recording medium.

To obtain a translucent recording medium, a transparent plastic film or glass is used as a substrate,
To obtain a glossy recording medium, an opaque plastic film or paper is used as a base material.

In preparing the recording medium of the present invention, first, the composition is added, if necessary, together with other additives.
Dissolve or disperse in water or alcohol, polyhydric alcohols, or other appropriate organic solvents to prepare a coating solution. The obtained coating solution is subjected to, for example, a roll coater method, a blade coater method, an air knife coater method, a gate roll coater method, a bar coater method, a size press method, a spray coat method, a gravure coater method, a force-coater method, or the like. Apply to the surface of the material. Thereafter, drying is performed using, for example, a hot-air drying furnace, a hot drum, or the like to obtain the recording medium of the present invention. Further, if necessary, a super calendering treatment or the like may be applied to smooth the ink receiving layer or increase the surface strength.

Next, the recording ink used in the present invention will be described. The dye ink used in the present invention is a water-soluble dye containing an anionic group and a water-soluble organic solvent and other components such as a viscosity adjuster, a pH adjuster, a preservative,
It comprises a surfactant, an antioxidant and the like.

The dye used in the present invention is not particularly limited as long as it is a water-soluble acid dye, direct dye or reactive dye described in the color index (COLOR INDEX). In addition, there is no particular limitation on those not described in the color index as long as they have an anionic group such as a sulfone group and a carboxyl group. The water-soluble dyes mentioned here include those having a pH dependency of solubility.

Examples of the water-soluble organic solvent used in the ink include amides such as dimethylformamide and dimethylacetamide; ketones such as acetone; ethers such as tetrahydrofuran and dioxane; polyalkylene glycols such as polyethylene glycol and polypropylene glycol; Ethylene glycol, propylene glycol, butylene glycol, triethylene glycol,
1,2,6-hexanetriol, thiodiglycol,
Alkylene glycols such as hexylene glycol and diethylene glycol; lower alkyl ethers of polyhydric alcohols such as ethylene glycol methyl ether, diethylene glycol monomethyl ether and triethylene glycol monomethyl ether; ethanol, isopropyl alcohol, n-butyl alcohol and isobutyl alcohol; In addition to monohydric alcohols, glycerin, N-methyl-2-pyrrolidone, 1,3-dimethyl-imidazolidinone, triethanolamine, sulfolane, dimethyl sulfoxide and the like are used. The content of the water-soluble organic solvent is not particularly limited, but is preferably 1 to 50% by weight, more preferably 2 to 30% by weight.
In addition, if necessary, additives such as a viscosity adjuster, a pH adjuster, a preservative, a surfactant, and an antioxidant evaporation promoter may be added. The choice of surfactant is critical to adjusting the permeability of the liquid.

A preferable physical property range of the ink is a temperature of 25.
At around ° C .: First, the pH should be 3-1
2. Surface tension is 10-60 dyn / cm, viscosity is 1-3
0 cps. Further, in order to further effectively implement the effects of the present invention, an anionic surfactant or an anionic polymer may be added to the ink in addition to the components described above. Alternatively, the amphoteric surfactant may be used after being adjusted to a pH higher than its isoelectric point. Examples of the anionic surfactant include carboxylate type, sulfate type, sulfonate type, phosphate type and the like, which can be used without any problem. Examples of the anionic polymer include an alkali-soluble resin, specifically, sodium polyacrylate or a polymer obtained by copolymerizing acrylic acid with a-part of the polymer. It is not limited to these.

Next, the black pigment ink is subjected to a pre-mixing treatment of the carbon black in a basic surfactant solution, and the dispersion liquid is subsequently milled by a high-shear-rate dispersing apparatus to remove coarse particles after dilution. To perform centrifugation. Thereafter, a material for a desired ink formulation is added, and an aging treatment is performed in some cases. After a while
Finally, centrifugation is performed to obtain a pigment dispersion having a desired average particle size. The pH of the ink thus produced is adjusted so as to be in the range of 2.5 to 6.0.

In the case of the particles of the carbon black ink prepared as described above, the average particle diameter is essential for the stability of the dispersion to be in the range of 80 to 200 nm, preferably in the range of 80 to 150 nm. . The surface tension of the ink is preferably in the range of 20 to 65 dyne / cm.

Next, regarding the ink jet recording method,
This will be described below. The ink jet recording method can be applied to any conventionally known ink jet recording method in which a small droplet of ink is ejected from a nozzle using various driving principles to perform recording. As a typical example, in the method described in the claims and examples of JP-A-54-59936, the ink that has been subjected to the action of thermal energy causes a rapid change in volume. An ink jet system in which ink is ejected from nozzles by force can be used.

An example of an ink jet recording apparatus suitable for the ink jet recording method of the present invention will be described below. FIGS. 1, 2, and 3 show examples of a head configuration which is a main part of the apparatus.
Shown in The head 13 is formed by bonding a glass, ceramic or plastic plate having a groove 14 through which ink passes to a heating head 15 (a head is shown in the figure, but is not limited to this) used for thermal recording. Is obtained. The heating head 15 includes a protective film 16 made of silicon oxide or the like, aluminum electrodes 17-1 and 17-2, a heating resistor layer 18 made of dichromium or the like, a heat storage layer 19,
It is made of a substrate 20 having good heat dissipation such as alumina. The ink 21 reaches a discharge orifice (fine hole) 22 and forms a meniscus 23 by the pressure P.

Now, when an electric signal is applied to the electrodes 17-1 and 17-2, the area of the heating head 15 indicated by n rapidly generates heat, and bubbles are generated in the ink 21 in contact with the area. The meniscus 23 protrudes, the ink 21 is ejected, becomes a recording droplet 24 from the orifice 22, and flies toward the recording sheet 25. FIG. 3 is an external view of a multi-head having a large number of heads shown in FIG. The multi-head is manufactured by closely contacting a heating plate 28 similar to that described in FIG. 1 with a glass plate 27 having a multi-groove 26. FIG. 1 is a sectional view of the head 13 along the ink flow path, and FIG. 2 is a sectional view taken along line 2-2 'in FIG.

FIG. 4 shows an example of an ink jet recording apparatus incorporating such a head. In FIG.
Is a blade as a wiping member, one end of which is held by a blade holding member to be a fixed end, and forms a cantilever. The blade 61 is disposed at a position adjacent to the recording area by the recording head, and in this embodiment, is held in a form protruding into the movement path of the recording head. Reference numeral 62 denotes a cap, which is disposed at a home position adjacent to the blade 61, and has a configuration in which the cap moves in a direction perpendicular to the direction in which the recording head moves and comes into contact with the ejection surface to perform capping. Further, 63 is an ink absorber provided adjacent to the blade 61, similar to the blade 61.
It is held in a form protruding into the movement path of the recording head.
The blade 61, the cap 62, and the absorber 63 constitute a discharge recovery section 64, and the blade 61 and the absorber 6
3 removes moisture, dust and the like from the ink ejection surface.

Reference numeral 65 denotes a recording head which has discharge energy generating means and discharges ink on a recording medium facing a discharge surface on which a discharge roller is disposed to perform recording, and 66 denotes a recording head 65 on which the recording head 65 is mounted. Is a carriage for performing the movement. The carriage 66 is slidably engaged with a guide shaft 67, and a part of the carriage 66 is connected to a belt 69 driven by a motor 68 (not shown). Thus, the carriage 66 can move along the guide shaft 67, and the recording head 65 can move the recording area and the area adjacent thereto.

Reference numeral 51 denotes a paper feed unit for inserting a recording medium, 5
Reference numeral 2 denotes a paper feed roller driven by a motor (not shown). With this configuration, the recording medium is fed to a position facing the ejection surface of the recording head, and is discharged with a discharge roller 53 as the recording proceeds. In the above configuration, when the recording head 65 returns to the home position at the end of recording or the like, the cap 62 of the head recovery unit 64 moves the recording head 6
5 or the blade 61 is protruding into the movement path. As a result, the ejection surface of the recording head 65 is wiped. When capping is performed by contacting the cap 62 with the protruding surface of the recording head 65, the cap 62 moves so as to protrude into the moving path of the recording head.

When the recording head 65 moves from the home position to the recording start position, the cap 62 and the blade 61 are at the same position as the position at the time of wiping described above. As a result, even during this movement, the ejection surface of the recording head 65 is wiped. The above-described movement of the print head to the home position is performed not only at the end of printing or at the time of ejection recovery, but also at a predetermined interval to the home position adjacent to the printing area while the printing head moves through the printing area for printing. The wiping is performed along with this movement. In the case of color printing, four colors of recording inks containing black, cyan, magenta, and yellow inks are arranged on the carriage 66 in parallel. Instead of arranging the recording heads in parallel, one recording head may be divided into four in a column. Further, the ink may be three colors of cyan, magenta, and yellow instead of four colors.

[0033]

The present invention will be described in more detail with reference to the following examples. In the following examples, parts are by weight unless otherwise specified.

Example 1 Ink receiving layer cation-modified polyvinyl alcohol (trade name: CM-3)
18, manufactured by Kuraray Co., Ltd., 100 parts of a saponification degree of about 89 mol%, a polymerization degree of about 1700, and a cationization degree of about 2 mol%, silica fine particles (Sylysia 470, average particle diameter of 12 μm, manufactured by Fuji Silysia Chemical Ltd.) ) Was dissolved and mixed with a composition consisting of 0.7 parts in terms of solid content using water as a medium. The obtained coating solution was applied to a polyethylene terephthalate film (trade name: Lumirror, thickness 100 μm, manufactured by Toray Industries, Inc.) using a wire bar so that the binder layer thickness after drying was 7 μm, and then 120 Drying at 3 ° C. for 3 minutes gave an ink receiving layer (b).

The ink receiving layer was further provided with a cation-modified polyvinyl alcohol (trade name: C
M-318, manufactured by Kuraray Co., Ltd., saponification degree: about 89 mol%,
Degree of polymerization about 1700, degree of cationization about 2 mol%) 100
Part, colloidal silica fine particles (trade name: Snowtec S
A composition consisting of 25 parts by weight of TC, average particle diameter of 10 to 20 nm, manufactured by Nissan Chemical Industries, Ltd.) was dissolved and mixed in water as a medium. The obtained coating solution was applied on the ink receiving layer (b) using a wire bar so that the thickness of the binder layer after drying was 3 μm.
After drying for a minute, the ink receiving layer (a) was provided to prepare the recording medium of the present invention.

Next, the following components were mixed, and a membrane filter having a pore size of 0.22 μm (trade name;
Fluoropore filter, manufactured by Sumitomo Electric Co., Ltd.), and yellow, magenta and cyan inks (1)
Y, (1) -M and (1) -C were obtained. (1) -Y CI direct yellow 86; 2 parts thiodiglycol; 10 parts acetylenol EH: 0.05 parts water; balance (total 100 parts) (1) -M dye was C.I. I Acid Red 289: Same composition as in Example (1) -Y, except that it was changed to 2.5 parts. (1) One C dye is C.I. Upper Acid Blue 9: Same composition as in Example (1) -Y, except that it was changed to 2.5 parts. (1) Black pigment ink Basic surfactant SF represented by the following structural formula (Formula 1)
The following Carbon Black Dispersion B-1 was prepared using the above l.

[0037]

Embedded image ・ SF1 10 parts ・ Carbon black Mogul L (5.0% volatile content, manufactured by Cabot Corporation) 25 parts ・ Water 130 parts These materials were charged into a 1-liter batch type vertical sand mill (IMEX). 200 ml of zirconium beads having a diameter of 1 mm was filled as a medium, and a dispersion treatment was performed at 2000 rpm for 3 hours while cooling with water. To suppress foaming at the beginning of dispersion, a very small amount of Surfynol 104E (manufactured by Nissin Chemical Co., Ltd.) was added. The viscosity of the liquid after dispersion is 5.2 cps, the pH is 3.5, and the surface tension is 60 dyne.
/ Cm. The dispersion was centrifuged to remove coarse particles to obtain a dispersion B-1 having an average particle diameter of 160 nm and a solid content of 16.5% by weight. Using this dispersion B-1, a black pigment ink having the following formulation and used in Examples of the present invention was prepared. -Dispersion B-1 30 parts-Diethylene glycol 25 parts-Water 45 parts The physical properties of the obtained ink were a viscosity of 2.0 cps, a surface tension of 55 dyne / cm, and a pH of 3.5. The average particle size was measured by a particle size distribution analyzer ELS-8 using a dynamic light scattering method.
00 (manufactured by Otsuka Electronics Co., Ltd.). The average value was shown as a value obtained from the initial gradient of the autocorrelation function.

Next, using the recording paper and ink obtained as described above, an ink jet recording head having 14 recording nozzles per mm and ejecting ink droplets by the action of heat is mounted. A color image was formed by the recording apparatus thus evaluated, and the recorded image was evaluated.

Example 2 Except that the colloidal silica fine particles (Snowtec ST-C, average particle diameter 10-20 nm, manufactured by Nissan Chemical Industries, Ltd.) of the ink receiving layer (a) were changed to 11 parts in terms of solid content. The recording medium of the present invention was prepared in the same manner as in Example 1.

Example 3 Except that the colloidal silica fine particles (Snowtec ST-C, average particle diameter 10-20 nm, manufactured by Nissan Chemical Industries, Ltd.) of the ink receiving layer (a) were changed to 42 parts in terms of solid content. The recording medium of the present invention was prepared in the same manner as in Example 1.

Example 4 A recording medium of the present invention was prepared in the same manner as in Example 1 except that the thickness of the ink receiving layer (a) was changed to 5 μm.

Comparative Example 1 Example 1 was repeated except that the colloidal silica fine particles (Snowtec ST-C, average particle diameter 10-20 nm, manufactured by Nissan Chemical Industries, Ltd.) of the ink receiving layer (a) were changed to 5 parts in terms of solid content. Similarly, the recording medium of the comparative example was adjusted.

Comparative Example 2 Same as Example 1 except that the colloidal silica fine particles (Snowtec ST-C, average particle size 10-20 nm, manufactured by Nissan Chemical Industries, Ltd.) of the ink receiving layer (a) were changed to 50 parts in terms of solid content. Thus, the recording medium of the comparative example was adjusted.

Comparative Example 3 Silica fine particles (Silicia 47) in the ink receiving layer (b)
0, average particle diameter 12 μm, manufactured by Fuji Silysia Chemical Ltd.)
Was changed to 11 parts in terms of solid content in the same manner as in Example 2 to prepare a recording medium of Comparative Example.

Comparative Example 4 A recording medium of the present invention was prepared in the same manner as in Example 1 except that the thickness of the ink receiving layer (b) was changed to 3 μm.

Comparative Example 5 A recording medium of the present invention was prepared in the same manner as in Example 1, except that the thickness of the ink receiving layer (b) was 7 μm and the thickness of the ink receiving layer (a) was 10 μm. The following items were evaluated for the obtained color print samples.

[Evaluation Items] (1) Cracking In the black pigment ink portion, a crack was observed in the pigment film by visual observation, and a crack was observed when the pigment film was not seen at all.

(2) Solid uniformity Black part and force part (Y, M, C and R, G, B)
Regarding the above, the case where beading was clearly observed on the projected image or visually and unevenness was conspicuous, the case where slight beading occurred was Δ, the case where no beading occurred and there was no unevenness was ○. Here, beading means that when the ink has fluidity before being fixed to the ink receiving layer, the dots move irregularly to the surface direction of the ink receiving layer surface, and the adjacent dots and new dots are moved. Is a phenomenon in which density unevenness occurs in a recorded image due to the formation of an aggregate. Bleed between the black and the power lines, those with clearly occurring bleeding between the boundaries of the black part and the power parts (Y, M, C and R, G, B) were evaluated as x. Δ, those that did not occur at all were rated as ○.

(3) Scratchability In an environment of 25 ° C./60%, after recording with full dots of each of two colors of black, yellow, cyan, and magenta, and letting stand for one hour, NP-DRY paper was added to the black part. (Manufactured by Canon) and 4 kg / cm ² from the top
When the paper was rubbed with the pressure and peeled off, the ink was clearly transferred to the paper and the recording part was clearly damaged, and x was marked when no transfer or damage was observed. .

(4) Ink drying property In an environment of 25 ° C./60%, after recording with full dots of each of two colors of black, yellow, cyan, and magenta, and letting stand for 2 minutes, the black part and the color part That is, when NP-DRY paper (manufactured by Canon Inc.) is superimposed on each of the full dot portions of each of the two colors of yellow, cyan, and magenta, and rubbed from above with a pressure of 4 kg / cm ² to remove the paper When the ink was clearly transferred to the paper and the recording part was clearly scratched, the transfer was marked as x, and the worst thousand was recognized. Those that did not exist were marked with ○. Table 1 shows the evaluation results.

[0051]

[Table 1]

[0052]

As described above, in the case of performing ink-jet recording using a pigment ink, the use of the recording medium embodying the present invention does not cause cracks in the printed portion, which is a practical problem. No scratching and ink drying. Further, the recording medium of the present invention can be shared with a conventional dye ink.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a head portion of an ink jet recording apparatus used in the method of the present invention.

FIG. 2 is a cross-sectional view of a head portion of an ink jet recording apparatus used in the method of the present invention.

FIG. 3 is an external perspective view of a head obtained by multiplying the head shown in FIGS. 1 and 2;

FIG. 4 is a perspective view showing an example of an ink jet recording apparatus.

[Explanation of symbols]

 Reference Signs List 13 Head 14 Groove for passing ink 15 Heating head 16 Protective film 17-1 Aluminum electrode 17-2 Aluminum electrode 18 Heating resistor layer 18 Heat storage layer 20 Substrate 21 Ink 22 Discharge orifice (fine hole) 23 Meniscus 24 Recording droplet 25 Recording Sheet 26 Multi-head 27 Glass plate 28 Heating head 51 Paper feed unit for inserting recording medium 52 Paper feed roller 53 Paper discharge roller 53 61 Wiping member 62 Cap 63 Ink absorber 64 Discharge recovery unit 65 Recording head 66 Carriage 67 Guide shaft 68 Motor 69 Belt

Continued on the front page F-term (reference) 2H086 BA16 BA32 BA35 BA45 BA51 BA53 4F100 AA01B AA01C AA20 AK01B AK01C AK21B AK21C AK42 AL06B AL06C AT00A BA03 BA10A BA10B BA27 CA13B DE01B DE01C EH46 J90YBJBJJBJJB14

Claims (4)

[Claims] 1. An ink jet recording medium having two ink receiving layers on at least one surface of a support,
An ink receiving layer (a) containing a water-soluble resin as a main component and having an average particle diameter of 1 μm or less and an inorganic fine particle content of 10 wt% or more and 30 wt% or less is provided farther from the support, and less than 10 wt% is closer to the support. An ink jet recording medium for pigment ink and dye ink, characterized in that the ink receiving layer (b) made of inorganic fine particles and a water-soluble resin is provided thicker than the ink receiving layer (a). 2. The recording medium according to claim 1, wherein the thickness of the ink receiving layer (a) is 5 μm or less and 2 μm or more. 3. The recording medium according to claim 1, wherein the water-soluble resin is a cation-modified polyvinyl alcohol. 4. The transparent ink jet recording medium according to claim 1, wherein the inorganic particles have an average particle diameter of 100 nm or less.