JPH10175367A - Inkjet recording sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet recording sheet having good ink coloring property, excellent transparency, weather resistance and water resistance, and high printing density. SOLUTION: In an ink jet recording sheet provided with an ink receiving layer on a transparent support, the ink receiving layer is
An ink jet recording sheet comprising: amorphous silica fine particles composed of secondary particles having an average particle diameter of 100 nm or less in which amorphous silica having an average primary particle diameter of 3 nm to 30 nm is aggregated; and an aqueous resin. . Preferably, the average secondary particle diameter of the amorphous silica fine particles is 10 nm to 100 nm.
And the haze value of the recording sheet is 20% or less.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording sheet, and more particularly, to a light transmissive ink jet recording sheet suitable for OHP, which is excellent in transparency, ink absorbency, water resistance, weather resistance, print density and image quality. Regarding the sheet.

[0002]

2. Description of the Related Art An ink jet recording system is a system in which ink droplets ejected from a nozzle at a high speed are adhered to a recording material for recording, and has features such as easy full-color printing and low printing noise. . In this method, since the ink used contains a large amount of solvent, it is necessary to use a large amount of ink in order to obtain a high recording density. In addition, since the ink droplets are continuously ejected, the next droplet is ejected before the first droplet is absorbed, which is likely to cause a disadvantage that the ink droplets are fused and ink dots are joined. Therefore, the recording sheet used in this ink jet recording method has a high density of print dots,
It is required that the color tone be bright and vivid, that the ink be absorbed quickly and that no bleeding of the ink occur even when print dots overlap. On the other hand, the light transmitting recording medium is O
It is widely used for conferences, conferences, briefings, lectures, etc. for HP. In addition, demand for recording media for signboards, show windows, and the like is increasing. Conventional light-transmitting recording media are mainly manufactured by an electronic copying system (PPC), but as the demand for colorization increases,
In recent years, an ink jet recording method that is excellent in the clarity of a recorded image has been attracting attention. As a base material of a light-transmitting (transparent) recording medium conventionally used for OHP or the like, generally, P
Plastic films such as ET (polyethylene terephthalate) can be mentioned, but since these films do not have sufficient water absorption, they do not absorb water-based ink for ink jet recording, and the ink flows and the image becomes unclear. In addition, because of poor drying of the ink, there was a disadvantage that the recorded image was stained or stuck due to rubbing or overlapping.

[0003] For general coating type ink jet paper, a porous pigment is provided as an ink receiving layer as a coating layer to control color and sharpness which determine image quality, thereby improving color reproducibility and image reproducibility. Has been planned. For example, JP-A-62-111782, JP-A-63-13
No. 776 and JP-A-63-104878, an ink receiving layer is prepared by using primary particles or secondary particles having pores as a pigment (generally silica, alumina or the like is used) and adding a binder. And an ink-jet recording sheet provided with the above. However, such an ink receiving layer has a remarkable lack of transparency, and cannot be used for OHP even if a transparent substrate is used.
In order to provide a plastic film with an appropriate ink absorbency while maintaining transparency, for example, JP-A-59-17
No. 4,381, JP-A-60-132785, JP-A-60-132
As disclosed in JP-A-145879 and JP-A-61-32788, it has been proposed to provide a recording layer made of a water-soluble polymer such as starch, a water-soluble cellulose derivative, polyvinyl alcohol, and polyvinylpyrrolidone on a film. However, all of these are insufficient in terms of the drying property (absorbency) and image quality (clearness and uniformity of the recording portion) of the ink and the water resistance of the recording layer.

JP-A-2-278870 discloses an ink receiving layer made of pseudo-boehmite. Small one
Absorbs relatively low molecular weight water and solvent (occupying about 90% or more of the ink components) in the ink between the next particles,
In this configuration, the dye in the ink is absorbed and fixed between the large secondary particles. In this case, it has a certain degree of transparency, and is superior in terms of ink dryness, image quality, and water resistance as compared with the above-described recording layer made of a water-soluble polymer, but the following problems still remain. . That is, pseudo-boehmite is a kind of alumina crystal, and the particles have a columnar or acicular shape, and the secondary particles aggregated from the acicular or columnar form have poor film-forming properties and are relatively easily cracked. . In addition, an ink having poor coloring properties with alumina (for example, Acid Red 52)
(Red color such as (edible red No. 106)). There is a problem that the pseudo-boehmite layer itself tends to yellow over time. Furthermore, pseudo-boehmite has a high cost and is not suitable for general use.

[0005]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems and provides an ink jet recording sheet having a high print density, excellent ink color development, excellent transparency, weather resistance and water resistance. The purpose is.

[0006]

Means for Solving the Problems The present invention and the like have made intensive studies to solve the above problems, and as a result, have found that the average particle diameter of silica primary particles having a particle diameter of 3 nm to 30 nm aggregated on a transparent sheet-like support. Is provided with a silica fine particle composed of secondary particles having a particle size of 100 nm or less and a recording layer containing an aqueous resin as a main component, and the haze value of the coated sheet is preferably 20% or less, more preferably 10% or less. It has been found that a transparent ink jet recording sheet having excellent transparency, good color development of the ink, high ink absorption speed, high print density, and excellent weather resistance, ink fixability, and print suitability can be obtained.

[0007] The present invention includes the following aspects. [1] In an ink jet recording sheet having an ink receiving layer provided on a transparent support, the ink receiving layer has an average of 1
An ink jet recording sheet comprising an amorphous silica fine particle composed of secondary particles having an average particle diameter of 100 nm or less in which amorphous silica having a secondary particle diameter of 3 nm to 30 nm is aggregated, and an aqueous resin. [2] The average secondary particle diameter of the amorphous silica fine particles is 1
The inkjet recording sheet according to [1], wherein the thickness is 0 nm to 100 nm and the haze value of the recording sheet is 20% or less. [3] The inkjet recording sheet according to [1], wherein the haze value is 20% or less.

[4] The aqueous resin is a polyvinyl alcohol having a degree of polymerization of 2,000 or more [1] to [1].
The inkjet recording sheet according to any one of [3]. [5] The inkjet recording sheet according to any one of [1] to [4], wherein the polyvinyl alcohol has a saponification degree of 95% or more. [6] The ink jet recording sheet according to any one of [1] to [5], wherein the ink receiving layer contains a cationic resin.

The haze value is determined according to JIS K 7105.
For example, a haze meter (reflection / transmittance; HR-100,
(Murakami Color Research Laboratory). The lower the haze value, the higher the transparency. The measurement was performed by the following method. 1. Attach a standard white board and follow the instructions
Adjust the amount of incident light according to (T ₁ ). 2. With the standard white plate still attached, a test piece is attached, and the total amount of transmitted light (T ₂ ) is measured. 3. The standard white plate and the test piece are removed, and a light trap is attached, and the amount of scattered light (T ₃ ) of the device is measured. 4. With the light trap attached, a test piece is attached, and the amount of light scattered by the apparatus and the test piece (T ₄ ) is measured. The value of haze was determined by the following calculation method. Total light transmittance T _t (%) = (T ₂ / T ₁ ) × 100 Diffuse light transmittance T _d (%) = [[T ₄ −T ₃ (T ₂ / T
₁ )] / T ₁ ] × 100 Haze degree H (%) = (T _d / T _t ) × 100

The haze value has no lower limit, and can be set to 5% or less. However, when the size is extremely reduced, there is a concern that the ink absorbency may decrease. If the haze value of the coated sheet is higher than 20%, the projected image becomes dark when projected on an OHP.
When the amorphous silica fine particles of the present invention are used, a coated sheet having a haze value of 20% or less can be obtained.
Care must be taken when the coating amount is too large or the haze value of the substrate itself is too high, because the haze value of the coated sheet may be high.

The primary particles of the amorphous silica are easily formed into a spherical shape, the obtained secondary particles are easily formed into a film, and the coating film is hardly cracked. In addition, amorphous silica has good coloring properties of ink and is low in price, so that it may be extended to general use. Commercially available amorphous silica is a powder having a diameter of several microns and has a high ink absorbency, but has no transparency, and can be used as a general coated paper, but it does not provide print density and transparency. It is possible. In the present invention, since specific silica fine particles are used, an ink jet recording sheet having excellent transparency and ink jet suitability can be obtained. The silica fine particles of the present invention consist essentially of secondary particles formed by aggregation of primary particles. In the case of a silica sol in which the primary particles are monodispersed (for example, a commercially available colloidal silica),
The porous layer obtained by coating the base material becomes relatively dense, easily loses transparency, and a high coating amount is unavoidable in order to have ink absorption. If the coating amount is high, the coating film tends to be cracked, and the coating process tends to be complicated. Of course, primary particles may be partially contained in the amorphous silica fine particles of the present invention.

Since the amorphous silica fine particles of the present invention have little self-adhesiveness, it is essential to add a binder to obtain an ink receiving layer. When the ink receiving layer of the ink jet recording sheet of the present invention is composed mainly of silica fine particles and preferably a water-soluble resin (particularly, polyvinyl alcohol is preferred), the transparency of the entire ink receiving layer is high, and Since a transparent feeling is obtained, the printing density is high, and the transmission density is high, a clear image can be obtained when projected by OHP or the like.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The support is a substrate having transparency, and preferably has a haze value of 20% or less, and more preferably has a haze value as low as possible. For example cellophane,
Polyethylene, polypropylene, soft polyvinyl chloride,
Examples thereof include plastic films and sheets such as rigid polyvinyl chloride and polyester (such as polyethylene terephthalate). Next, the ink receiving layer of the present invention will be described in detail. First, a layer which is mainly composed of silica fine particles including secondary particles formed by agglomeration of amorphous silica primary particles having a particle diameter of 3 nm to 30 nm which constitute the ink receiving layer of the present invention will be described. The silica fine particles used in the present invention are obtained by applying a strong force to a commercially available synthetic amorphous silica (several microns) by mechanical means. That is, it can be obtained by a breaking down method (a method of subdividing a bulk raw material). The silica fine particles of the present invention are preferably used in the form of colloid particles or slurry from the viewpoint of particle stability. As mechanical means,
Examples include mechanical methods such as ultrasonic waves, high-speed rotation mills, roller mills, container driving medium mills, medium stirring mills, jet mills, grinders, and sand grinders. The average particle diameter in the present invention is a particle diameter observed with an electron microscope (SEM and TEM) (an electron micrograph of 10,000 to 400,000 times is taken, and the Martin diameter of particles in 5 cm square is measured and averaged. (See “Particle Handbook”, Asakura Shoten, p. 52).

The average particle size of the aggregated amorphous silica fine particles (the aggregates are also referred to as secondary particles in the present invention) used in the present invention is 100 nm or less, preferably 10 to 100 n.
m, more preferably 20 to 80 nm. If the average particle diameter of the aggregates is small, the ink absorption rate may be difficult to be obtained. On the other hand, if the average particle diameter is large, the transparency may be lost, the print density may be reduced, and the transparency of a desired blank portion (preferably the haze value 20% or less) and an ink jet recording sheet having the density and transparency of the printed portion cannot be obtained. The primary particles constituting the silica fine particles used in the ink receiving layer are 3 nm.
It needs to be adjusted to ３０30 nm. If it is less than 3 nm, the gap between the primary particles becomes extremely small, and the ability to absorb the solvent and the colorant (dye or pigment) in the ink is significantly reduced. On the other hand, when the primary particles exceed 30 nm, the aggregated secondary particles become large, and the transparency of the ink receiving layer decreases.

Since the silica fine particles of the present invention themselves have little film-forming property, when they are provided as an ink receiving layer, it is essential to add an adhesive. An aqueous resin is used as the adhesive (binder). Modified polyvinyl alcohol such as polyvinyl alcohol (hereinafter also referred to as PVA) or silyl-modified polyvinyl alcohol, casein, soy protein,
Synthetic proteins, starch, polyvinylpyrrolidone,
Water-soluble resins such as cellulose derivatives such as carboxymethylcellulose and methylcellulose, and various latexes and emulsions such as styrene-butadiene copolymer latex are appropriately added and used. A water-soluble resin is preferred from the viewpoint of ink absorption. Here, PVA is most effective from the viewpoint of dispersion suitability, paint stability, and adhesiveness. In particular, in order to obtain dispersibility and ink absorbency, a polymerization degree of 200
Zero or more PVAs are preferably used. In order to obtain water resistance, PVA having a saponification degree of 95% or more is effective.

The solid content weight ratio of the silica fine particles of the present invention to the adhesive is 10/1 to 10/10, preferably 10/2 to 2/10.
It is adjusted in the range of 10/6. If the amount of the adhesive is large, the pores between the particles become small, and a sufficient ink absorption rate may not be obtained in some cases. On the other hand, when the amount of the adhesive is small, the coating layer is cracked. If necessary, other pigments may be blended in addition to the silica fine particles / adhesive (binder) of the present invention as long as transparency is not impaired. For example, colloidal silica (dispersion of primary particles), kaolin, clay, calcined clay, zinc oxide, tin oxide, magnesium sulfate, aluminum oxide, aluminum hydroxide, calcium carbonate, satin white, aluminum silicate, smectite, zeolite, silicate Various pigments known and used in the general coated paper field, such as magnesium, magnesium carbonate, magnesium oxide, diatomaceous earth, styrene plastic pigment, urea resin plastic pigment, and benzoguanamine plastic pigment, are appropriately used.

A cationic resin may be added to the ink receiving layer. Thereby, the ink fixability can be improved. As the cationic resin to be added,
For example, polyalkylene polyamines such as polyethylene amine and polypropylene polyamine, or derivatives thereof, acrylic resins having tertiary amino groups and quaternary ammonium groups, diacrylamine, and the like can be given. In addition,
The amount of the cationic resin to be added is adjusted in the range of 1 to 100 parts by weight, more preferably 5 to 50 parts by weight, based on 100 parts by weight of the pigment. In addition, various auxiliaries such as a dispersant, a thickener, an antifoaming agent, a coloring agent, an antistatic agent, and a preservative used in the production of general coated paper are appropriately added. Although not coating amount is particularly limited, 1~100g / m ^2, preferably preferably adjusted to 5 to 60 g / m ^2. 1g
/ M ^2, it is difficult to obtain a uniform coating film, and 100 g / m 2
^If it exceeds ² , the effect is saturated, and the coating film may be easily cracked or the transparency may be reduced. In order to obtain a high coating amount of 15 g / m ² or more, it is also possible to realize a coating amount of two or more times in addition to increasing the viscosity and increasing the concentration of the coating solution. The layer mainly comprising the amorphous silica fine particles of the present invention may be a single layer or a multilayer. In the case of a multilayer, it is possible to balance ink absorption speed, transparency, and ink absorption capacity as a layer in which the mixing ratio of the silica fine particles and the binder is changed. Further, for example, a layer mainly composed of a hydrophilic resin is provided as a lower layer to improve the ink absorption capacity, to prevent cracking of the upper layer (a layer mainly composed of silica fine particles), and to improve the adhesion to the substrate. It can also be improved.

For the purpose of increasing the adhesiveness, the substrate can be subjected to corona treatment or various anchor coating treatments. Examples of a coating apparatus for obtaining the ink receiving layer include various known apparatuses such as a blade coater, an air knife coater, a roll coater, a bar coater, a gravure coater, a rod blade coater, a die coater, a lip coater, and a curtain coater.

The ink used in the ink jet recording method of the present invention comprises, as essential components, a dye for forming an image and a liquid medium for dissolving or dispersing the dye, and, if necessary, various dispersants and an interface. It is adjusted by adding an activator, a viscosity adjuster, a specific resistance adjuster, a pH adjuster, a fungicide, a stabilizer for dissolving or dispersing the recording agent, and the like. The recording agents used in the ink include direct dyes, acid dyes, basic dyes,
Examples thereof include reactive dyes, food dyes, disperse dyes, oil dyes, and various pigments, and conventionally known dyes can be used without any particular limitation. The content of such a dye is determined depending on the type of the liquid medium component, the characteristics required for the ink, and the like, but in the case of the ink of the present invention, the composition as in the conventional ink, that is, There is no particular problem in use at a ratio of about 0.1 to 20% by weight. Examples of the solvent for the ink used in the present invention include water and various water-soluble organic solvents, for example, having 1 to 4 carbon atoms such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, and isobutyl alcohol. Alkyl alcohols, ketones or ketone alcohols such as acetone and diacetone alcohol, polyalkylene glycols such as polyethylene glycol and polypropylene glycol, ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, thiodiglycol, Alkylene glycols having 2 to 6 alkylene groups such as xylene glycol and diethylene glycol, amides such as dimethylformamide, ethers such as tetrahydrofuran, and glycerin Ethylene glycol methyl ether,
And lower alkyl ethers of polyhydric alcohols such as diethylene glycol methyl (ethyl) ether and triethylene glycol monomethyl ether.

[0020]

The present invention will be described in more detail with reference to the following Examples, but it should be understood that the present invention is by no means restricted thereto.
Unless otherwise specified, parts and% in the examples are solid contents excluding water, and represent parts by weight and% by weight, respectively. [Silica sol A] Synthetic amorphous silica having an average particle diameter of 3 μm (Nipsil HD, manufactured by Nippon Silica Industry Co., Ltd.)
-2, primary particle diameter: 11 nm), dispersed by a sand grinder, and then sonicated. The dispersion operation of the sand grinder and the ultrasonic wave was repeated until the average aggregate particle diameter became 30 nm, and a 15% aqueous solution was used. Was prototyped. [Silica sol B] Synthetic amorphous silica having an average particle size of 9 μm (manufactured by Nippon Silica Industry Co., Ltd., trade name: Nipsil L)
(P, primary particle size: 16 nm), and after being dispersed by a sand grinder, ultrasonic waves are applied, and the dispersion operation of the sand grinder and the ultrasonic wave is repeated until the average particle size of the aggregates becomes 50 nm, and an 8% aqueous solution is dispersed. Prototype made.

[Silica Sol C] Synthetic amorphous silica having an average particle size of 9 μm (Nippon Silica Industry Co., Ltd., trade name: Nip
(sil NS, primary particle diameter: 21 nm), and after being dispersed by a sand grinder, ultrasonic waves were applied, and the dispersion operation of the sand grinder and the ultrasonic wave was repeated until the average particle diameter of the aggregates became 150 nm, and a 12% aqueous solution was used. Was prototyped. [Silica sol D] Synthetic amorphous silica having an average particle diameter of 3 μm (manufactured by Nippon Silica Industry Co., Ltd., trade name: Nipsil E-
170, primary particle diameter: 30 nm), and after dispersing with a sand grinder, applying ultrasonic waves, and repeating the operation of dispersing the sand grinder and ultrasonic waves until the average particle diameter of the aggregates becomes 300 nm. Prototype made.
The particle size of the dispersion is measured as follows. Observation was made with a TEM (transmission electron microscope, H-300, manufactured by Hitachi, Ltd.). After the dispersion was diluted to 0.5%, it was dropped on a collodion film, air-dried, and used for observation. Electron microscope magnification: 2
It was appropriately selected from 10,000 times, 50,000 times, and 100,000 times.

Example 1 100 parts of the above silica sol A was mixed with polyvinyl alcohol (Kuraray Co., trade name: PVA-124, degree of polymerization: 240).
0, saponification degree: 98.5%) A 100 μm-thick PET film (Melinex D53) was mixed with an 8% aqueous solution obtained by mixing 40 parts with a Meyer bar so that the coating amount was 20 g / m ^2.
5; ICI, haze value 0.5%)
An ink jet recording sheet of the present invention was produced. Example 2 A 100% silica sol B mixed with 40 parts of polyvinyl alcohol (manufactured by Kuraray Co., trade name: PVA-124, degree of polymerization: 2400, degree of saponification: 98.5%) was coated with a 12% aqueous solution using a Meyer bar. PET film (Melinex D53) having a thickness of 100 μm so that the coating amount is 20 g / m ^2.
5; ICI, haze value 0.5%)
An ink jet recording sheet of the present invention was produced.

Example 3 A 10% aqueous solution obtained by mixing 40 parts of polyvinyl alcohol (manufactured by Kuraray Co., trade name: PVA-117, degree of polymerization: 1700, degree of saponification: 98.5%) with 100 parts of silica sol A was used as a Mayer. PET film (Melinex D535; 100 μm thick) so that the coating amount is 20 g / m ² with a bar.
(ICI, haze value 0.5%) The surface was coated and dried to produce an ink jet recording sheet of the present invention. Example 4 To 100 parts of silica sol A, an 8% aqueous solution obtained by mixing 40 parts of polyvinyl alcohol (manufactured by Kuraray Co., Ltd., trade name: PVA-235, degree of polymerization: 3500, degree of saponification: 88.0%) was applied using a Mayer bar. Thickness 1 so that the work volume is 20 g / m ²
00 μm PET film (Melinex D535; I
CI, haze value: 0.5%) The surface was coated and dried to produce an ink jet recording sheet of the present invention.

Example 5 A styrene / butadiene copolymer latex (trade name: 0693, manufactured by Nippon Synthetic Rubber Co., Ltd.) was added to 100 parts of silica sol A.
A 100% PET film (Melinex D535; ICI, manufactured by ICI, with a haze value of 0.1%) was applied to a 20% aqueous liquid mixed with 0 parts with a Meyer bar so that the coating amount was 20 g / m ² .
5%) The composition was coated and dried on the surface to produce an inkjet recording sheet of the present invention. Comparative Example 1 A 15% aqueous solution obtained by mixing 40 parts of polyvinyl alcohol (manufactured by Kuraray Co., Ltd., trade name: PVA-124, degree of polymerization: 2400, degree of saponification: 98.5%) with 100 parts of silica sol C was applied with a Meyer bar. PET film (Melinex D53) having a thickness of 100 μm so that the coating amount is 20 g / m ^2.
5; ICI, haze value 0.5%)
An ink jet recording sheet of the present invention was produced.

Comparative Example 2 PVA (manufactured by Kuraray Co., Ltd., trade name: PVA-124, degree of polymerization: 2400, degree of saponification: 9) was added to 100 parts of silica sol D.
8.5%) A 15% aqueous solution obtained by mixing 40 parts with a Meyer bar is 100 μm thick so that the coating amount is 20 g / m ^2.
PET film (Melinex D535; manufactured by ICI,
(Haze value: 0.5%) The surface was coated and dried to produce the ink jet recording sheet of the present invention. Comparative Example 3 100 parts of synthetic amorphous silica (manufactured by Nippon Silica Industry Co., Ltd., trade name: Nipsil HD-2, primary particle diameter: 11 nm) having an average particle diameter of 3 μm was added to polyvinyl alcohol (trade name, manufactured by Kuraray Co., Ltd.) : PVA-124, degree of polymerization: 240
0, a saponification degree: 98.5%) using a 15% aqueous solution mixed with 40 parts, and using a Meyer bar, a 100 μm thick PET film (Melinex D535; manufactured by ICI, so that the coating amount is 20 g / m ²⁾ . (Haze value: 0.5%) The surface was coated and dried to produce the ink jet recording sheet of the present invention.

Comparative Example 4 Polyvinyl alcohol (Kuraray Co., Ltd., trade name: PVA-
117, degree of polymerization: 1800, degree of saponification: 98.5%) using a 10% aqueous solution, and a coating amount of 20 g /
A 100 μm-thick PET film (Melinex D535; manufactured by ICI, haze value: 0.5%) was applied to the surface to a thickness of m ² and dried by drying to produce the inkjet recording sheet of the present invention. [Evaluation Method] The quality of the ink jet recording sheets obtained in Examples 1 to 5 and Comparative Examples 1 to 4 was evaluated by the following method. Ink jet recording is performed using a commercially available ink jet printer (trade name: BJC-60, manufactured by Canon Inc.).
0J) was used.

[Haze value (transparency)]
According to SK 7105, HR manufactured by Murakami Color Research Laboratory
It measured using -100. (The lower the haze value, the higher the transparency.) [Water resistance] Water droplets were dropped on an ink jet recording sheet, and after 30 minutes, the water droplets were wiped off, and the portion immersed in the water droplets was rubbed with a hand to evaluate the water resistance. ：: No change was observed in the ink receiving layer. Δ: The ink receiving layer was partially removed. X: The ink receiving layer was completely removed. [Ink absorption (ink drying)] Black, yellow, magenta, and cyan are printed in solid colors, and high quality paper is stuck on the printed surface every 5 seconds immediately after printing, and the ink is transferred to the high quality paper. Observe whether or not. The time until no transfer occurs at all is measured. The number of seconds measured was evaluated. When the time until the ink dries is 10 seconds or less, the ink absorbency is excellent. ◎: less than 5 seconds ○: 5 or more and less than 10 seconds △: 10 or more and less than 50 seconds ×: 1 minute or more

[Print Density] A commercially available coated paper was spread under each ink jet recording sheet, and the print density of a solid black portion was measured using a Macbeth reflection densitometer (Macbeth, RD-920). The numbers shown in the table are the average values of five measurements. [OHP Projectivity] The printed inkjet recording sheet was projected onto an OHP, and the sharpness of the projected image was visually determined. A: The background is bright and the projected image is extremely clear. ：: The background is slightly dark, but the projected image is clear and at a practical level. Δ: The background is dark and the projected image is unclear. ×: The background is black and the projected image is not visible.

[0029]

[Table 1]

[0030]

As is clear from Table 1, the ink jet recording sheet obtained by the constitution of the present invention has high transparency, good ink drying property, high printing density, high fineness, and OHP. This is an ink jet recording sheet having excellent projection properties. The present invention is a transparent ink jet recording sheet having excellent transparency, good ink color development, high ink absorption speed, high print density, and excellent weather resistance, ink fixability, and print suitability.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Koichi Yasui 1-10-6 Shinonome, Koto-ku, Tokyo Inside Oji Paper Co., Ltd. Shinonome Research Center

Claims (2)

[Claims] 1. An ink jet recording sheet having an ink receiving layer provided on a transparent support, wherein said ink receiving layer has an average primary particle diameter of 3 nm to 30 nm and an average particle diameter of aggregated amorphous silica of 100 nm or less. An ink-jet recording sheet comprising fine particles of amorphous silica composed of secondary particles and an aqueous resin. 2. The ink-jet recording according to claim 1, wherein the average particle diameter of the secondary particles of the amorphous silica fine particles is 10 nm to 100 nm, and the haze value of the recording sheet is 20% or less. Sheet.