JP2001105719A - Recording medium and manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a recording medium having excellent preservation stability of a print image. SOLUTION: The recording medium comprises a surface layer containing particles having photocatalytic activity and formed on at least an part not brought into contact with the image to be formed. In this case, as the particle, a titanium dioxide particle having a primary particle size of 0.001 to 0.2 μm is preferred. Or, (i) titanium dioxide particles surface treated with a porous substance having no photocatalytic activity, and/or (ii) a titanium dioxide particles enclosed by a porous wall made of a substance having photocatalytic activity is preferred.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a recording medium and a method for manufacturing the same. More specifically, the present invention relates to a recording medium capable of forming a printed image with improved storage stability, particularly useful for inkjet recording, and a method for producing the same.

[0002]

2. Description of the Related Art Ink jet printers have low noise,
It has features such as low running cost and easy color recording, and has been rapidly spreading in recent years as a digital signal output device. As the recording ink used in the ink jet printer, an ink using a water-based dye or an oil-based dye as a colorant, an ink in which a pigment is dispersed in an aqueous or oil-based medium, or a colorant dispersed in a heat-meltable resin or the like can be used. Various types of inks, such as dissolved solid inks, have been proposed.

[0003] Above all, water-based ink is considered to be most suitable for social demands for maintaining the global environment because of the high safety of the ink material to the human body and the environment and the relatively low energy consumption of the printer. In general, aqueous inks are mainly used for inkjet recording inks because of their excellent safety and the like as described above. Aqueous dyes are mainly used in aqueous inks because they have high solubility in aqueous media mainly composed of water as a coloring agent. However, there is a problem that the aqueous dye fades only when it is placed indoors. Therefore, it is desired to improve the storage stability of an ink jet printed image.

For the purpose of preventing fading by air pollutants such as sulfur oxides and nitrogen oxides, for example, Japanese Patent Application Laid-Open No.
No. 5796 discloses that on a substrate, a compound (A) selected from a thiourea derivative, a thiosemicarbazide derivative and a thiocarbohydrazide derivative, and iodine,
Compound (B) selected from iodide, dithiocarbamate, thiocyanate and thiocyanate
A recording material sheet having a porous ink receiving layer containing the same has been proposed, but the effect of preventing fading is insufficient.

In order to purify air pollutants such as sulfur oxides and nitrogen oxides, see, for example, Japanese Patent Application Laid-Open No. 10-219.
No. 920 proposes a NOx purification extruded building material in which a titanium dioxide-containing coating layer having a thickness of 20 to 500 μm is formed on the surface of an extruded cement building material. No example used for the media is known.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a recording medium which can form a printed image having improved storage stability and is particularly useful for ink jet recording.

[0007]

Means for Solving the Problems The inventors of the present invention have made intensive studies to solve the above-mentioned problems of the conventional recording medium, and as a result, a portion of the recording medium which does not contact a print image to be formed. The present inventors have found that the conventional problems can be solved by forming a surface layer containing particles having photocatalytic activity, and have completed the present invention.

[0008] The present invention relates to the following recording media (1) to (8). (1) A recording medium having a surface layer containing particles having photocatalytic activity on at least a part of a part which does not contact a printed image to be formed. (2) The particles having a photocatalytic activity have a primary particle diameter of 0.0
The recording medium according to (1), wherein the recording medium is titanium dioxide particles having a diameter in a range of from 01 to 0.2 μm. (3) The titanium dioxide particles having the above primary particle diameter are:
(2) titanium dioxide particles surface-treated with a porous substance having no photocatalytic activity, and / or (ii) titanium dioxide particles contained in a porous wall made of a substance having no photocatalytic activity. The recording medium according to the above.

(4) The recording medium according to (3), wherein the substance having no photocatalytic activity is at least one selected from calcium phosphate, calcium silicate and silicon dioxide. (5) At least a portion where a printed image is formed is at least selected from (i) a porous layer formed of inorganic fine particles and a hydrophilic polymer binder component and (ii) a hydrophilic polymer layer. The recording medium according to any one of (1) to (4), wherein an ink receiving layer composed of a kind of layer is formed.

(6) The inorganic fine particles constituting the porous layer are silica, and the hydrophilic polymer binder component is selected from polyvinyl alcohol, polyacrylamide, poly N-vinylacetamide and modified products and copolymers thereof. The recording medium according to (5), which is at least one selected from the group consisting of: (7) The recording medium according to (5), wherein the hydrophilic polymer layer is made of at least one selected from polyvinyl alcohol, polyacrylamide, poly N-vinylacetamide, and modified products and copolymers thereof. (8) The recording medium according to any one of (1) to (7) for inkjet recording.

(9) A method for manufacturing a recording medium, comprising forming a surface layer containing particles having photocatalytic activity on at least a part of a part which does not come into contact with a printed image to be formed. (10) The method for producing a recording medium according to (9), wherein titanium dioxide particles having a primary particle size in a range of 0.001 to 0.2 μm are used as the particles having photocatalytic activity. (11) The titanium dioxide particles having the above primary particle diameter,
(10) titanium dioxide particles surface-treated with a porous substance having no photocatalytic activity, and / or (ii) titanium dioxide particles contained in a porous wall made of a substance having no photocatalytic activity. The manufacturing method of the recording medium according to the above.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a recording medium according to the present invention will be described. The recording medium of the present invention has a surface layer containing particles having photocatalytic activity in at least a part of a portion which does not contact a printed image to be formed. Here, the “part that does not come into contact with the print image to be formed” means that the print image formation material adheres when a print image formation material such as ink using a dye or pigment as a colorant is applied using a printer or the like. The area where the printed image is not formed.

For example, in a sheet-shaped recording medium on which a print image is formed on one side, the “part that does not come into contact with the print image to be formed” means a blank portion of the print image formation surface and a back surface (a print image non-formation surface). Plane). The margin portion of the print image forming surface mainly refers to a portion where a print image cannot be formed due to the mechanism of the print image recording device, and is usually a top margin portion,
The lower margin part and the margin parts on both sides. However, even if it is an area where a print image can be formed for design reasons or the like, this area can be regarded as a part of the margin when a print image is not formed.

As will be described later, a layer made of a porous transparent material containing particles having photocatalytic activity and having a property of transmitting a colorant of a printing image forming material such as ink without absorbing it is used. In the case of a sheet-shaped recording medium formed on the surface on which an image is to be formed (consisting of a print image forming area and a blank portion), when a print image forming material is applied, ink or the like is included in the porous transparent material. Since the colorant of the printed image forming material is not fixed, the layer made of the porous transparent material can be regarded as the "portion not in contact with the printed image to be formed" in the present invention.

In the recording medium of the present invention, the surface layer containing the particles having photocatalytic activity is formed on the entire portion that does not come into contact with the print image to be formed (hereinafter referred to as “print image non-contact portion”). It is not necessary to be provided, and it is sufficient if the printed image is formed in at least a part of the non-contact portion.

The particles having photocatalytic activity are preferably fine particles of titanium dioxide in view of their photocatalytic ability. The primary particle size of the titanium dioxide fine particles (refers to the average particle size of the primary particles; hereinafter the same) is from 0.001 to 0.2.
The range of μm is preferred. If the primary particle size is less than 0.001 μm, it is difficult to efficiently produce the particles, which is not practical. Conversely, if it exceeds 0.2 μm, the properties as a photocatalyst deteriorate. A more preferred primary particle size is in the range of 0.005 to 0.1 μm.

The production method of the titanium dioxide particles preferably used in the present invention is not limited as long as it basically has a photocatalytic activity, and its crystal form may be any. And those having a crystal type containing brookite as a main component are preferred. However, titanium dioxide, which is generally used for paint pigments, has a dense layer of alumina or silica on the particle surface,
It is not preferable because the photocatalytic activity is reduced.

For the purpose of improving the photocatalytic ability of the titanium dioxide particles, other metal elements such as platinum, rhodium, ruthenium, palladium, silver, copper, zinc and nickel can be carried on the titanium dioxide particles. The loading of these metal elements may be carried out by a conventional method, and the loading amount is usually selected in the range of 0.001 to 10% by weight based on the weight of titanium dioxide particles.

The titanium dioxide particles having the primary particle diameter may be (i) titanium dioxide particles surface-treated with a porous material having no photocatalytic activity, and / or (ii) a porous material comprising a material having no photocatalytic activity. More preferably, the particles are titanium dioxide particles contained in the wall. Decompose air pollutants by using titanium dioxide particles surface-treated with a porous substance having no photocatalytic activity and / or titanium dioxide particles contained in a porous wall made of a substance having no photocatalytic activity It is possible to suppress the deterioration of the base material of the recording medium and the binder for fixing the particles having photocatalytic activity to the base material without losing the photocatalytic ability.

The substance having no photocatalytic activity refers to a substance which does not or hardly exhibits catalytic activity by light. For example, aluminum oxide, silicon oxide, oxides such as zirconium oxide, calcium hydroxide, hydroxides and hydrated oxides such as zirconium hydroxide, aluminum phosphate, calcium phosphate, phosphates such as apatite, calcium silicate, silica Aluminum silicate, zirconium silicate, barium silicate, strontium silicate,
Silicates such as magnesium silicate, cement, lime,
Examples include silicate-containing substances such as frit for enamel, clay minerals such as montmorillonite, smectite, kaolin, sepiolite, and hydrotalcite, and layered silicate minerals such as mica and talc. Particularly, calcium phosphate, calcium silicate and silicon dioxide can be more preferably used. These substances can be used alone or in combination of two or more.

There is no particular limitation on the method of preparing particles surface-treated with a porous substance having no photocatalytic activity. For example,
In the slurry in which the titanium dioxide particles are dispersed, a method of depositing a substance having no photocatalytic activity on the surface of the particles in a porous state can be adopted. Further, a precursor of a porous substance can be attached to the surface of the titanium dioxide particles, and the precursor can be converted into a porous substance. For example, a method of attaching a silicone oligomer or a silane coupling agent to titanium dioxide particles and converting it to porous silica by firing, an aqueous solution of a water-soluble aluminate such as sodium aluminate, or sodium hydroxide, magnesium hydroxide A method of dispersing titanium dioxide particles in an aqueous solution in which aluminum or aluminum hydroxide is dissolved in a solution such as, and neutralizing the dispersion with an acid to precipitate porous alumina, attaching a metal alkoxide to the titanium dioxide particles,
A method of precipitating a porous metal oxide by hydrolysis can be employed.

The method for producing the titanium dioxide particles contained in the porous wall made of a substance having no photocatalytic activity is not particularly limited. For example, a method of preparing an inorganic porous microcapsule containing titanium dioxide particles, and a titanium dioxide particle obtained by rolling a porous spherical base material, for example, expanded obsidian (pearlite), a fine metal wire, or a ceramic fiber. , Foamed cement or the like. In the latter method, in order to support the titanium dioxide particles, techniques such as sintering by heat treatment, adhesion with a binder, and impregnation into a porous substrate can be employed.

In the recording medium of the present invention, a method for forming a surface layer containing particles having photocatalytic activity in at least a part of a non-contact portion of a printed image is not particularly limited. For example, a method of fixing particles having photocatalytic activity to a substrate together with an organic material binder such as polyvinyl alcohol, polyethylene glycol, gelatin or an inorganic material binder such as silicate; molding by molding a plastic molding material mixed with particles having photocatalytic activity Using the article as a substrate of a recording medium; a method of forming a porous film containing particles having photocatalytic activity, and laminating the porous film on the surface of a non-contact portion of a printed image; and a pulp slurry of particles having photocatalytic activity A method in which paper made by mixing with a paper material such as paper is used as a base material of a recording medium can be used. When a substrate containing particles having photocatalytic activity is prepared, the thickness of the recorded portion is made sufficient so that the colorant in the printed image forming material does not contact the substrate itself, or particles containing photocatalytic activity are contained. Care must be taken to provide a layer not to be provided between the substrate and the printed image. Further, a substance such as silica or activated carbon having a property of adsorbing air pollutants and particles having photocatalytic activity may be mixed and used.

The portion where the print image is to be formed on the recording medium is not particularly limited as long as it can hold the print image forming material, such as paper, cloth, synthetic resin sheet, etc. Recording medium, in order to improve the quality of a printed image, at least one selected from (i) a porous layer formed from inorganic fine particles and a hydrophilic polymer binder component and (ii) a hydrophilic polymer layer. It is more preferable to have an ink receiving layer composed of one kind of layer.

As the inorganic fine particles used for forming the porous layer (i), fine particles of a substance selected from silica, alumina, and pseudo-boehmite are preferable. Specific examples of the hydrophilic polymer binder component used for forming the porous layer (i) and the hydrophilic polymer used for forming the hydrophilic polymer layer (ii) include polyvinyl alcohol,
Polyethylene glycol, gelatin, starch, poly N
-Vinylacetamide, polyacrylamide, polyvinylpyrrolidone and their modified products, copolymers and the like.

The method of preparing the portion where the print image is to be formed is not particularly limited. In the case of a porous layer composed of inorganic fine particles and a hydrophilic polymer binder component, the inorganic fine particles are dispersed in water, a hydrophilic polymer binder component is added, and a pH adjuster, a crosslinking agent, a surfactant, An ink receiving layer solution is prepared by mixing additives such as an antioxidant and an ultraviolet absorber, and is coated on a substrate using a coating device such as a bar coater, a roll coater, an air knife coater, a blade coater, and a rod coater. A porous layer can be formed by coating and drying. The ink receiving layer composed of the hydrophilic polymer layer can be prepared by a method in which the inorganic fine particles are removed from the above method.

As the base material of the recording medium, a polyester film such as polyethylene terephthalate, a plastic film such as a polyethylene film or paper can be used. In order to improve the adhesion between these substrates and the ink receiving layer formed thereon, a discharge treatment or an undercoat may be applied to the surface of the substrate.

Further, a layer containing particles having photocatalytic activity may be formed in the non-contact portion of the printed image by using a commercially available sheet for an ink jet printer as a recording medium. Examples of commercially available paper for inkjet printers include Hewlett-Packard's Premium Inkjet Paper and Premium Photo Paper, such as Seiko Epson Corporation's Photo Print Paper and Superfine Paper. And glossy films for Super Fine, high-quality plain paper, and the like, photo glossy paper, photo glossy film, color BJ high-grade exclusive paper, plain paper for color BJ, etc., manufactured by Canon Inc. The recording medium thus prepared can be particularly preferably used for ink jet recording, and can also be used as a general recording medium for printed images.

[0029]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to Examples, but the present invention is not limited to these Examples. Preparation Example 1 of Photocatalytic Titanium Dioxide Particles To 250 L of pure water, 600 g of a commercially available polycarboxylic acid-type polymer surfactant (Kao Corporation Poise 530) was added.
Titanium dioxide ultra fine particles (Showa Titanium Co., Ltd.)
F4, 12 kg of primary particles (average particle diameter of 0.03 μm) was charged and subjected to dispersion treatment to obtain a slurry. Separately, NaCl, NaHPO ₄ , KH ₂ PO ₄ , KCl, M
After adding gCl ₂ .6H ₂ O and CaCl ₂ and mixing with the above titanium dioxide slurry, Na ⁺ was 139 mM, K ⁺ was 2.8 mM, Ca ²⁺ was 1.8 mM, and Mg ²⁺ was 0.5 m.
350 L of a simulated body fluid prepared such that M and Cl ^- became 144 mM and HPO ₄ ^- became 1.1 mM.

The titanium dioxide slurry (250 L) and the simulated body fluid (350 L) were mixed, and the temperature was maintained at 40 ° C. for 24 hours. Then, the mixture is dried to 10
kg of particles were obtained. When the photoactivity (initial oxygen consumption rate) of the particles was measured using the oxidation reaction of tetralin, the change in oxygen partial pressure was 9.8 × 10 ⁻² kPa / min.
(Takashi Shizuno, Titanium oxide, physical properties and applied technology, Gihodo Shuppan, p196-197,
1991). These particles are referred to as photocatalyst particles A.

Preparation Example 2 of Photocatalytic Titanium Dioxide Particles Particles were obtained in the same manner as in Preparation Example 1, except that sodium alkylnaphthalene sulfonate (Perox NB-L, Kao Corporation) was used as a surfactant. When the photoactivity of the particles was measured, the change in oxygen partial pressure was 10.1 × 10 ⁻² k.
Pa / min. These particles are referred to as photocatalyst particles B.

Preparation Example 3 of Photocatalytic Titanium Dioxide Particles Particles were obtained in the same manner as in Preparation Example 1, except that sodium hexametaphosphate (special grade reagent manufactured by Junsei Chemical Co., Ltd.) was used as a surfactant. When the photoactivity of the particles was measured, the change in oxygen partial pressure was 10.7 × 10 ⁻² kPa / min. These particles are referred to as photocatalyst particles C.

Preparation Example 4 of Photocatalytic Titanium Dioxide Particles As ultrafine titanium dioxide particles, the primary particles have an average particle size of 0.1.
Particles were obtained in the same manner as in Preparation Example 1, except that a particle having a diameter of 06 μm (F2 manufactured by Showa Titanium Co., Ltd.) was used. When the photoactivity of the particles was measured, the change in oxygen partial pressure was 9.6 × 1.
It was 0 ^-2 kPa / min. These particles are referred to as photocatalyst particles D
And

Preparation Example 5 of Photocatalytic Titanium Dioxide Particles Ca ²⁺ after mixing with titanium dioxide slurry was 0.9 m
Particles were obtained in the same manner as in Synthesis Example 1, except that the composition of the simulated body fluid was adjusted so that M and HPO ₄ ^- became 9.6 mM. When the photoactivity was measured, the change in oxygen partial pressure was 10.9 ×
It was 10 ^-2 kPa / min. These particles are referred to as photocatalyst particles E.

Preparation Example 6 of Photocatalytic Titanium Dioxide Particles Ultrafine titanium dioxide particles (F4 manufactured by Showa Titanium Co., Ltd., average particle size of primary particles 0.03 μm) were added to 55 L of an aqueous sodium silicate solution (silicon dioxide concentration: 4 mol / L). )
5 kg was charged and dispersion treatment was performed to obtain a slurry. Separately, a commercially available sorbitan fatty acid ester type nonionic surfactant (Reodol S manufactured by Kao Corporation) is dissolved in 100 L of toluene.
(P-O30) was prepared.
The titanium dioxide slurry was added to a toluene solution to prepare a uniform emulsion. Subsequently, this emulsion was added to 440 L of a 4 mol / L aqueous ammonium sulfate solution, and the temperature was further maintained at 40 ° C. for 2 hours. Thereafter, the slurry was dried and washed with water to obtain 4 kg of particles. When the photoactivity using the oxidation reaction of tetralin was measured, it was found that the change in oxygen partial pressure was 7.8 × 10 ⁻² kPa / min and the photocatalytic activity was high. These particles are referred to as photocatalyst particles F.

Preparation Example of Coated Paper 1 Precipitated silica (Fine Seal X-37 manufactured by Tokuyama Corporation)
B) 25 g of pure water was dispersed in 225 g of pure water to obtain a slurry. This slurry was added to a polyvinyl alcohol aqueous solution (PVA-217 manufactured by Kuraray Co., Ltd.) previously adjusted to a concentration of 10% by weight.
100 g, Baycoat 20 (manufactured by Nippon Light Metal Co., Ltd.) 1 g
And stirred to obtain a coating liquid for an ink receiving layer. This coating solution was applied to a high-quality paper (Sunflower 180 kg, manufactured by Oji Paper Co., Ltd.) cut into A4 size using a bar coat so that the dry film thickness became 30 μm. After drying at 50 ° C. for 30 minutes, it was placed in a 140 ° C. oven for 30 seconds. The coated paper thus obtained is referred to as coated paper A.

Preparation Example 2 of Coated Paper The same as Preparation Example 1 of coated paper except that a dispersion of 15 g of gel silica (Silicia 350 manufactured by Fuji Silysia K.K.) and 135 g of pure water was used as the silica slurry. The coated paper obtained by the method is referred to as coated paper B.

Preparation Example 3 of Coated Paper Same as Preparation Example 1 of coated paper except that a dispersion of 36 g of fumed silica (Aerosil 380 manufactured by Nippon Aerosil Co., Ltd.) and 324 g of pure water was used as the silica slurry. To obtain a coated paper. The coated paper thus obtained is referred to as coated paper C.

Preparation Example of Coated Paper 4 Concentration: 10% by Weight Instead of Polyvinyl Alcohol Aqueous Solution
Poly N-vinylacetamide (GE manufactured by Showa Denko KK)
-192L) 80 g aqueous solution and 10% by weight aqueous polyvinyl alcohol solution (Kuraray Co., Ltd. PVA-217)
A coated paper was obtained in the same manner as in coated paper preparation example 1 except that 20 g was used. The coated paper thus obtained is referred to as coated paper D.

Example of Preparation of Coated Paper 5 Concentration 10% by Weight Instead of Polyvinyl Alcohol Aqueous Solution
100 g of an aqueous solution of N-vinylacetamide / sodium acrylate copolymer (Biac GE-167L manufactured by Showa Denko KK), and sorbitol polyglycidyl ether (Denacol EX-614B manufactured by Nagase Kasei Kogyo Co., Ltd.) instead of Baycoat 20 Coated paper was obtained in the same manner as in Coated paper preparation example 1 except that 1 g of was used. The coated paper thus obtained is referred to as coated paper E.

Preparation Example of Coated Paper 6 N-vinylacetamide / sodium acrylate copolymer having a concentration of 10% by weight (Biac GE- manufactured by Showa Denko KK)
167 L) 1 g of sorbitol polyglycidyl ether (Denacol EX-614B) was added to 100 g of an aqueous solution,
The mixture was stirred to obtain a coating liquid for an ink receiving layer. Apply this coating solution to A
A fine paper cut into four sizes (Sunflower 180 kg, manufactured by Oji Paper Co., Ltd.) was coated with a bar coat so as to have a dry film thickness of 30 μm. After drying at 50 ° C for 30 minutes,
Placed in a 40 ° C. oven for 30 seconds. The coated paper thus obtained is referred to as coated paper F.

Preparation of Recording Medium Example 1 25 g of photocatalyst particles A were dispersed in 225 g of pure water to obtain a slurry. A polyvinyl alcohol aqueous solution (PVA-21 manufactured by Kuraray Co., Ltd.) previously adjusted to a concentration of 10% by weight in the slurry.
7) 100 g, Baycoat 20 (manufactured by Nippon Light Metal Co., Ltd.)
1 g was added and stirred to obtain a coating liquid. This coating solution was applied to the back surface of the ink receiving layer of the coated paper A by a bar coat so that the dry film thickness became 10 μm, and dried at 50 ° C. for 30 minutes. After applying the coating liquid to the cross section of the paper with a brush,
Dried at 30 ° C for 30 minutes, and 3c around the surface of the ink receiving layer.
The coating liquid was applied with a brush having a width of m, dried at 50 ° C. for 30 minutes, and then placed in an oven at 140 ° C. for 30 seconds to obtain a recording medium.

Examples 2 to 6 Five types of recording media were obtained in the same manner as in Example 1 except that coated paper B to coated paper F were used instead of coated paper A.

Example 7 A recording medium was obtained in the same manner as in Example 1 except that high quality paper (Sunflower 180 kg, manufactured by Oji Paper Co., Ltd.) was used instead of the coated paper A.

Example 8 A recording medium was obtained in the same manner as in Example 1 except that Premium Photo Paper, a paper dedicated to inkjet manufactured by Hewlett-Packard Co., was used instead of the coated paper A.

Example 9 A recording medium was obtained in the same manner as in Example 1 except that instead of the coated paper A, a photo print paper 2 manufactured by Seiko Epson KK was used.

Example 10 A recording medium was obtained in the same manner as in Example 1, except that the coated paper A was replaced with a photo-gloss paper GP-301 manufactured by Canon Inc. for exclusive use in inkjet printing.

Examples 11 to 15 Recording media were obtained in the same manner as in Example 1 except that photocatalyst particles BF were used instead of photocatalyst particles A, respectively.

Preparation and Evaluation of Recording Medium The recording medium prepared in Examples 1 to 15 was prepared using a commercially available ink jet printer PM-770C manufactured by Seiko Epson Corporation, using high-definition color digital standard image data (ISO / JIS). -SCID) was printed at the center of the recording medium to obtain an evaluation sample. As a comparative example,
Fine paper not coated with photocatalyst particles (Sunflower 180 kg, manufactured by Oji Paper Co., Ltd.) [Comparative Example 1], coated papers A to F
[Comparative Examples 2 to 7], inkjet-only paper (Hewlett-Packard Co., Ltd. inkjet-only paper premium photo paper) [Comparative Example 8], Seiko Epson Corporation inkjet-only paper photo-printed paper [Comparison] Example 9], and a comparative evaluation sample was printed in the same manner on a photo-glossy paper GP-301 [Comparative Example 10] manufactured by Canon Inc. for inkjet only. As a reference sample, a sample printed under the same conditions and stored in a closed container at 23 ° C. in a dark place was prepared.

The storage stability of the printed image was evaluated for each sample. That is, in a room where a commercially available petroleum fan heater was used for 8 hours during the day, these samples were left at a distance of 2 m from the petroleum fan heater for one month, and then the samples of Examples in which photocatalyst particles were coated and the samples were coated. By comparing the sample of the comparative example with the reference sample, the degree of fading of the printed image was visually observed. The results of the observation were evaluated by the following three-grade method. Grade ○ Almost no fading is observed Grade 中 Moderate fading is observed Grade × Remarkably fading is observed As a result of the evaluation, the print image storage stability of each of the samples of Examples 1 to 15 is Grade ○, and the photocatalyst particles The samples of Comparative Examples 1 to 7 where no photocatalyst particles were coated were rated X, and the samples of Comparative Examples 8 to 10 where no photocatalyst particles were coated were rated Δ.

[0051]

According to the present invention, the storage stability of a printed image to be recorded is improved by forming a surface layer containing particles having photocatalytic activity on at least a part of the non-contact portion of the recording medium. can do. The recording medium of the present invention is useful as a recording medium for printing and a printer, particularly as a recording medium for inkjet recording.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Katsura Ito 1 Shiga, Shiojiri-shi, Nagano Prefecture Showa Denko KK Shiojiri Lab. F-term (reference) Shiojiri Lab., Ltd. 2C056 EA13 FB01 FB03 FC06 2H086 BA12 BA14 BA15 BA16 BA24 BA31 BA33 BA35 BA46

Claims (11)

[Claims] 1. A recording medium having a surface layer containing particles having photocatalytic activity at least in a part that does not contact a printed image to be formed. 2. The recording medium according to claim 1, wherein the particles having photocatalytic activity are titanium dioxide particles having a primary particle size in the range of 0.001 to 0.2 μm. 3. The titanium dioxide particles having a primary particle diameter are (i) titanium dioxide particles surface-treated with a porous substance having no photocatalytic activity, and / or (ii) a substance having no photocatalytic activity. 3. The recording medium according to claim 2, wherein the recording medium is titanium dioxide particles contained in a porous wall. 4. The recording medium according to claim 3, wherein the substance having no photocatalytic activity is at least one selected from calcium phosphate, calcium silicate and silicon dioxide. 5. A method according to claim 1, wherein at least a portion where a print image is formed is provided.
Claims wherein an ink receiving layer comprising (i) a porous layer formed from inorganic fine particles and a hydrophilic polymer binder component and (ii) at least one layer selected from hydrophilic polymer layers is formed. Item 5. The recording medium according to any one of Items 1 to 4. 6. The inorganic fine particles constituting the porous layer (i) are silica, and the hydrophilic polymer binder component is polyvinyl alcohol, polyacrylamide, poly N-vinylacetamide and modified products and copolymers thereof. The recording medium according to claim 5, which is at least one selected from the group consisting of: 7. The method according to claim 5, wherein the hydrophilic polymer layer (ii) comprises at least one selected from polyvinyl alcohol, polyacrylamide, polyN-vinylacetamide, and modified products and copolymers thereof. recoding media. 8. The recording medium according to claim 1, which is for inkjet recording. 9. A method for manufacturing a recording medium, comprising forming a surface layer containing particles having photocatalytic activity on at least a part of a part which does not contact a printed image to be formed. 10. The method for producing a recording medium according to claim 9, wherein titanium dioxide particles having a primary particle size in the range of 0.001 to 0.2 μm are used as the particles having photocatalytic activity. 11. The titanium dioxide particles having a primary particle diameter described above comprise (i) titanium dioxide particles surface-treated with a porous substance having no photocatalytic activity, and / or (ii) a substance having no photocatalytic activity. The method for producing a recording medium according to claim 10, wherein the recording medium is titanium dioxide particles contained in a porous wall.