WO2003076201A1

WO2003076201A1 - Inkjet recording paper

Info

Publication number: WO2003076201A1
Application number: PCT/JP2003/002753
Authority: WO
Inventors: Takehiro Yoshimatsu; Yuji Ozawa; Akinobu Chatani; Noriko Kumazawa
Original assignee: Nippon Paper Industries Co., Ltd.
Priority date: 2002-03-08
Filing date: 2003-03-07
Publication date: 2003-09-18
Also published as: AU2003211850A1

Abstract

An inkjet recording paper of general paper type, which comprises a base paper and, being applied on or impregnated into at least one surface thereof, a liquid coating comprising an alumina compound and a water-soluble inorganic salt containing a divalent or trivalent metal ion as main materials. The liquid coating is preferably applied on or impregnated into the base paper in an amount of 0.2 to 3 g/m2 in terms of dry solids per one surface.

Description

Inkjet recording paper Technical field

The present invention relates to an ink jet recording paper, and more particularly, to a plain paper type ink jet recording paper which is apparently like plain paper but has better ink absorbability and image quality than ordinary plain paper. Background art

The recording paper of the ink jet recording method is roughly classified into a plain paper type similar in texture to so-called high-quality paper and PPC paper, and at first glance a coated paper type having an ink receiving layer. Of these, plain paper type ink jet recording paper does not have or has very few ink receiving layers that can be clearly distinguished from paper supports. It is suitable for general writing such as the above, and is inexpensive. Therefore, in recent years, the use of the plain paper type ink jet recording paper is expanding, and a plain paper type ink jet recording paper capable of printing with high image quality comparable to the coated paper type has been demanded.

Generally, ink jet recording paper is required to have the following performance.

(1) Ink absorption f Good ink quality, ink droplets adhering to the surface of the recording paper quickly penetrate into the paper layer, become apparently dry, and come into contact with the recording device, other recording paper, hands, etc. Also does not cause dirt. .

(2) Ink droplets diffuse and penetrate unnecessarily into or on the recording paper, and the dots recorded by the ink droplets do not become too large or distorted.

(3) High print density by inkjet recording.

In particular, the plain paper type ink jet recording paper has a problem that the required characteristics of the above (2) and (3) are inferior to the coated paper type ink jet recording paper. Normally, plain paper type ink jet recording paper Because the pulp Hi is exposed to the surface, the ink bleeds along the nt, which causes a problem of so-called feathering. Therefore, it is necessary to solve the feathering problem to achieve the required characteristics of (2). As a means for improving feathering, Japanese Patent Application Laid-Open No. 5-69538 discloses an ink jet recording paper in which the amount of liquid transfer is controlled by a Bristow method when a water-soluble polymer is applied to the surface of a base paper. I have.

However, this ink jet recording paper could not sufficiently solve the problem of feathering, and the print density was not sufficient. Japanese Patent Application Laid-Open No. 2001-187486 discloses an ink jet recording paper containing hardwood pulp in the surface layer of base paper. Japanese Patent Application Laid-Open No. 2001-200199 discloses a (meth) atalinoleate and a cation on a base paper surface. Discloses an ink jet recording paper coated with a coating agent containing a cationic group-containing copolymer obtained by copolymerizing a cationic monomer. However, these ink jet recording papers were inferior in ink absorbency, and a satisfactory ink jet recording paper could not be obtained yet.

On the other hand, from the viewpoint of achieving the required characteristics of (3), attempts have been made to improve the image quality by fixing the ink on the surface layer by increasing the sizing property and increasing the print density. However, in this method, the ink absorbency is reduced, and the recording device, other recording paper, a hand, or the like comes into contact with the ink, thereby causing a stain S, or, in multicolor printing, bleeding at a boundary between different colors (bleeding). ). In addition, when the sizing property is reduced, the above-mentioned problems of contamination and bleeding are solved. The ink sinks quickly because ink is absorbed quickly, and there is a disadvantage that the print density is reduced. Therefore, there has been a demand for the development of ink jet recording paper which has a high print density and does not impair the absorbability of the ink. JP-A-4-320877, JP-A-4-323075, and JP-A-10-193781 are characterized in that an alumina compound is used from the viewpoint of the fixability and absorption of an ink dye. The claimed invention is described.

Therefore, the first object of the present invention is to not only prevent the occurrence of feathering but also to increase the print density and ink absorption and to achieve a high level of ink jet recording paper of the coated paper type. It is to use plain paper type ink jet recording paper that can obtain excellent print quality.

A second object of the present invention is to provide a plain paper type ink jet having a high ink drying speed, which not only has a high print density but also does not cause contamination even if a recording device, other recording paper, a hand, etc. comes into contact immediately after printing. To provide recording paper. Disclosure of the invention

The first invention according to the present invention provides a base paper comprising, on at least one surface thereof, a coating liquid containing an alumina compound and a water-soluble inorganic salt containing a divalent or trivalent metal ion as a main material, and a dry solid content per one surface. An ink jet recording paper, which is coated or impregnated so as to have a thickness of 0.2 to 3 g / m ² .

In the second invention, not only the printing density is high but also a recording device, other recording paper, or a hand immediately after printing prepared by adding an aeronic surfactant to the coating solution. This is a plain paper type ink jet recording medium that does not cause contamination even if it comes into contact with the paper. BEST MODE FOR CARRYING OUT THE INVENTION

Next, the present invention will be described in more detail.

The base paper used in the present invention is uncoated paper made of wood cellulose fiber, and this paper is mainly composed of papermaking pulp. Examples of papermaking pulp include chemical pulp such as LBKP and NBKP, mechanical pulp such as GP and TMP, and waste paper pulp. The present invention is not particularly limited to these. In addition, these papermaking pallets / revs can be used alone or in combination as needed.

In the present invention, various additives such as a filler, a sizing agent, and a paper strength enhancer to be internally added to the base paper are not particularly limited, and may be appropriately selected from known fillers and various internal additives. Can be used. If necessary, an antifoaming agent, a pH adjustment »lj, a dye or color pigment for adjusting hue, a fluorescent dye for improving visual whiteness, and the like can be internally added. The alumina compound used in the present invention includes, but is not particularly limited to, aluminum oxide, aluminum hydroxide, alumina hydrate having a boehmite structure, or a mixture thereof. From the viewpoint of ink absorption, the average particle size is 5 m or less (measuring device: Master Sizer-1 (laser diffraction type particle size measurement), manufacturer: Malvern Instruments, import destination: SiberHegner Co., Ltd. Japan) Alumina hydrate having a mite structure is preferred.

Examples of the water-soluble inorganic salt having a divalent or trivalent metal ion used in the coating liquid of the present invention include zinc chloride, aluminum chloride, cadmium chloride, calcium chloride, rare earth chloride, cerium chloride, conort chloride, and trichloride. Titanium, chromium chloride, tin chloride, ferrous chloride, ferric chloride, cupric chloride, lead chloride, Eckerl chloride, vanadium trichloride, hibarium salt, salt <magnesium salt, salt manganese And so on. Among the above-mentioned water-soluble inorganic salts, cerium chloride, magnesium chloride, calcium chloride, manganese chloride, and aluminum chloride are preferable in that the printing density is improved. The above-mentioned inorganic salt is preferably used in an amount of 30 to 80% by weight, particularly preferably 40 to 60% by weight, based on the alumina compound (anhydrous component). If the amount of the inorganic salt is small, the effect of suppressing feathering is small, and if the amount is too large, a problem such as discoloration of a printed image occurs.

In the present invention, the above-mentioned alumina compound and a water-soluble inorganic salt containing a divalent or trivalent metal ion are dissolved using water or a solvent containing water as a main component to form an aqueous coating liquid. . From the viewpoint of uniformly applying or impregnating the base paper, the concentration (solid content) of the coating liquid is preferably 10% by weight or less. In the present invention, the coating liquid is applied or impregnated at a low coating amount of 0.2 to 3 g Zm ^{2 in} terms of dry solid content per one side. Therefore, a thick coating layer is not formed on the base paper surface in the present invention. For example, when the cross section of the ink jet recording paper of the present invention is observed with a microscope or the like, it can be observed that solids (alumina compounds, inorganic salts, etc.) in the coating liquid adhere to the pulp of the base paper. The layers cannot be observed. If the concentration of the coating liquid is increased and the coating amount is increased, a coating layer is formed on the surface of the base paper. However, in this case, not only powder powder occurs but also the texture as plain paper is impaired. Will be In the present invention, since the inorganic salt present on the surface of the recording paper rapidly agglutinates the coloring material in the ink, the extent to which the ink spreads along the pulp fibers (feathering) on the surface of the recording paper decreases. Conceivable. It is also conceivable that the inclusion of the alumina compound improves the ink absorbency of the recording paper, thereby suppressing excessive bleeding in the horizontal direction and reducing feathering. In the present invention, a water-soluble film-forming resin may be contained in the coating liquid in order to impart surface strength to the ink jet recording paper. Specific examples of these film-forming resins include starch, oxidized starch, phosphorylated esterified starch, cationized starch, fully saponified polyvinyl alcohol, partially saponified polyvinyl alcohol, force-modified polybutyl alcohol, and silanol. Modified polyvinyl alcohol, Ayuon-modified polyvinyl alcohol, casein and the like can be mentioned. These water-soluble polymers can be used as warworms or in combination as needed. Further, a cationic resin may be included to impart water resistance to the ink. The film-forming resin can be contained in the coating solution in an appropriate amount within a range in which the effects of the present invention can be obtained. It is preferable that the film-forming resin be contained in an amount of 0 to 50% by weight in the solid content of the coating solution.

In the present invention, when an alumina compound and a metal-containing water-soluble inorganic salt are combined, the coating liquid may thicken, and it may be difficult to apply the coating uniformly. In such a case, the viscosity can be suppressed by adding an ayuonic surfactant to the coating solution.

Therefore, the surfactant used in the coating liquid of the present invention is an anionic surfactant which has an effect of suppressing a thickening caused when an alumina compound and a water-soluble inorganic salt containing a metal are mixed. It is necessary to be. The aeon-type surfactant protects the surface by binding to the alumina compound, prevents direct contact between the water-soluble inorganic salt containing metal and the alumina compound, and increases viscosity by this action. It is considered to be prevented. Such anionic surfactants can be appropriately selected from those known in the art. Specific examples include polyoxyethylene lauryl ether acetic acid, sodium polyoxyethylene lauryl ether acetate, and polyoxyethylene tridecyl. Sodium ether acetate, Nina polyoxyethylene alkyl sulfosuccinate Thorium, laurinyl sodium sodium polyoxyethylene sulfosuccinate, lauryl linadium sodium sulfosuccinate, sodium sodium polyoxyethylene lauroyl sulphosuccinate, sodium sodium polyoxyethylene lauryl ether sulfate, polyoxyethylene lauryl ether Triethanolamine sulfate, sodium polyoxyethylene alkyl ether sulfate, triethanolamine alkyl sulfate, sodium higher alcohol sulfate, sodium alkyl sulfate, sodium alkyl diphenyl ether disulfonate, sodium octyl sulfosuccinate

And ammonium lauryl sulfate, sodium dodecylbenzenesulfonate, condensate of naphthalenesulfonic acid and formalin, sodium anolekynaphthalenesulfonic acid, potassium alkyl phosphate, and the like. In the present invention, sodium octylsulfosuccinate, sodium polyoxyethylene alkyl ether sulfate, and sodium alkyldiphenylethersulfonate are particularly preferable in that the effect of suppressing thickening is high. The surfactant can be used in an appropriate amount as long as the effect of the present invention can be obtained. However, it is preferable to add the surfactant in an amount of 1 to 5% by weight based on the alumina compound.

The ink jet recording paper of the present invention comprises a coating liquid containing the above-described alumina compound, a water-soluble inorganic salt containing a divalent or trivalent metal ion, and an aeon-type surfactant added as necessary. It can be produced by a method of impregnating the base paper and drying it, or a method of applying it to the surface of the base paper and drying it. Known methods can be used for both the impregnation method and the coating method. For example, an impregnating type size press device can be used as the impregnating method, and a known coating method such as a roll coater, a gravure coater, a gate roll coater, a simsizer, a bar coater, etc., can be used as a method of applying to the base paper surface. Processing equipment can be used. In the present invention, it is particularly preferable to use an online impregnation type size press in terms of productivity.

The viscosity of the coating liquid is preferably 35 OmPas or less, as measured using a rotational viscometer according to the S method of JISK7117. In particular, when the coating is performed using an online size press device, it is preferable that the pressure be 10 OmPas or less. Drying methods include, for example, steam heaters, gas heaters, infrared heaters

, An electric heater, a heat heater, a microwave heater, a cylinder dryer, etc. After drying, if necessary, a smooth finish can be imparted by a finishing process such as a post-processing such as a super calender or a soft calender. In addition, any common paper processing means can be used.

From the viewpoint of the ink drying speed, the degree of stiffness (seconds) of the ink jet recording paper is preferably 20 seconds or less, particularly preferably 10 seconds or less, and more preferably 5 seconds or less. The degree of steak sizing can be adjusted by adjusting the amount of the internal sizing agent of the base paper or by adding the external sizing agent to the above-mentioned coating solution. The above-mentioned internal sizing agent and external sizing agent can be used in combination. Example

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto. The parts and percentages in the examples are parts by weight and percentage by weight of solids unless otherwise specified.

Broadleaf bleached kraft pulp (freeness: 350 ml CSF) For 100 parts of strong pulp slurry, 8 parts of talc, 1.8 parts of sulfuric acid band, 0.3 parts of cationized starch, retention aid 0.0 1 5 parts, was added及Pi rosin sizing agent 0.5 parts, and papermaking dried twin wire type paper machine to prepare a base paper having a basis weight of 7 4 _§ 111 ^2.

Example 1

On one side of the base paper prepared above, a coating liquid containing 3% of boehmite alumina (average particle size 2.9 μm) and 1.5% of aluminum chloride Coating was performed using a wire bar so as to obtain 2 g Zm ² per minute, followed by drying to obtain an ink jet recording paper of Example 1.

Example 2.

Ink jet recording paper of Example 2 was obtained in the same manner as in Example 1 except that manganese chloride was used instead of aluminum chloride used in Example 1. Example 3.

Ink jet recording paper of Example 3 was obtained in the same manner as in Example 1 except that calcium chloride was used instead of aluminum chloride used in Example 1.

Example 4.

An ink jet recording sheet of Example 4 was obtained in the same manner as in Example 1 except that cerium chloride was used instead of aluminum chloride used in Example 1.

Embodiment 5.

Ink jet recording paper of Example 5 was obtained in the same manner as in Example 1 except that magnesium chloride was used instead of aluminum chloride used in Example 1.

Embodiment 6.

Ink jet recording paper of Example 6 was obtained in the same manner as in Example 1 except that manganese sulfate was used instead of aluminum chloride used in Example 1.

Embodiment 7.

Ink jet recording paper of Example 7 was obtained in the same manner as in Example 1 except that magnesium sulfate was used instead of aluminum chloride used in Example 1.

Example 8

An ink jet recording paper of Example 8 was obtained in the same manner as in Example 1 except that calcium nitrate was used instead of the aluminum chloride used in Example 1.

Embodiment 9.

Ink jet recording paper of Example 9 was obtained in the same manner as in Example 1 except that magnesium nitrate was used instead of aluminum chloride used in Example 1.

Comparative Example 1

An ink jet recording paper of Comparative Example 1 was obtained in the same manner as in Example 1 except that sodium chloride was used instead of aluminum chloride used in Example 1.

Comparative example 2.

Ink jet recording paper of Comparative Example 2 was obtained in the same manner as in Example 1 except that sodium sulfate was used instead of aluminum chloride used in Example 1.

Comparative example 3.

On one side of the base paper prepared above, boehmite alumina (average particle size 2.9 μm) m) A coating liquid containing 3% was applied using a wire bar so that the coating amount was 2 gZm ² in terms of dry solid content, and dried to obtain the ink jet recording paper of Comparative Example 3. Example 4.

On one surface of the base paper prepared in the above, ethylene vinyl acetate-based latex coating solution containing (Sumikafuretsu task, Sumitomo Chemical machine) 3%, as the coating amount is ² gZm 2 on a dry solids Wire The composition was applied using a bar and dried to obtain an ink jet recording paper of Comparative Example 4.

Comparative example 5.

On one side of the base paper prepared above, a coating liquid containing 3% boehmite anolemina (average particle size 2.9 μm) and 1.5% aluminum chloride was applied at a dry solids content. Coating was performed using a wire bar to 7 gZm ² , followed by drying to obtain an inkjet recording paper of Comparative Example 5.

Comparative example 6.

On one surface of the base paper prepared in the above, a coating solution containing 5% of aluminum chloride 1., was coated with a wire bar so that the coating amount is 7 g / m ² on a dry solids After drying, the ink jet recording paper of Comparative Example 6 was obtained.

The following evaluations were performed on the ink jet recording papers obtained in Examples 1 to 9 and Comparative Examples 1 to 6. The results are as shown in Table 1.

(Print density)

Solid printing (black) was performed with a printer (HP Deskjet 97 OCxi), and the printing density was measured 24 hours later using a Macbeth densitometer (RD918). 1. If it is 3 or more, there is no practical problem.

(Ink drying and raw)

For 〇, no smear occurs even if the print surface is rubbed immediately after printing. For X, if the print surface is rubbed immediately after printing, stain occurs.

(Feathering)

Black thin lines were printed with a printer (HP Deskjet 97 OCxi) and visually judged. The evaluation criteria were as follows: 〇: Feathering and line thickness were extremely small and good; △ Although feathering and thickening of lines are slightly observed, it is good as long as there is no practical problem.

, X were both poor in feathering and line thickness.

As is clear from Table 1, in Examples 1 to 9, an ink jet recording paper having good print density, ink drying property, and good feathering was obtained. On the other hand, in Comparative Examples 1 and 2 in which a monovalent water-soluble inorganic compound was added to the coating solution and Comparative Examples 3 and 4 in which no water-soluble inorganic salt was added, feathering occurred and the print density was insufficient. there were. Further, the printing density in Comparative Example 5 in which the coating amount exceeds 5 g Zm ^2, ink drying property, and is been made sufficient in terms of feathering, the surface feeling of the surface is different from a so-called plain paper, In addition, it could not be used as ink jet recording paper due to powder falling. Furthermore, in Comparative Example 6 in which the alumina compound was not blended, sufficient ink drying properties could not be obtained.

Example 10

On the base paper prepared as above, boehmite anoremina (average particle size 2.9 μm, ratio Surface area 2.72m ² / g) 3%, aluminum chloride 1.5% and aionic surfactant sodium dioctyl sulfosuccinate (Sammorin OT-70, trade name of Sanyo Chemical Co., Ltd.) 0 The coating liquid containing 09% was impregnated with a 2 roll size press at a coating speed of 500 mZ so that the dry solid content was 4 gZm ² (2 gZm ² per side). After drying, it was machine-rendered to obtain an ink jet recording medium of Example 10.

Example 1 1.

Instead of sodium octylsulfosuccinate used as an aionic surfactant in Example 10, anionic surfactant sodium polyoxyethylene alkyl ether sulfate (Sandet ENM, a product of Sanyo Chemical Co., Ltd.) Name) The inkjet recording medium of Example 11 was obtained in the same manner as in Example 10 except that 0.09% was used. Example 12

An ink jet recording medium of Example 12 was obtained in the same manner as in Example 10, except that cerium chloride was used instead of aluminum chloride used in Example 10.

Example 13.

An inkjet recording medium of Example 13 was obtained in the same manner as in Example 10, except that magnesium chloride was used instead of aluminum chloride used in Example 10. Example 14.

Same as Example 10 except that the impregnation coating amount of 4 g / m ² (2 g / m ² per side) in Example 10 was changed to 0.1 lg / m ² (0.05 g / m ² per side) Thus, an inkjet recording medium of Example 14 was obtained.

Example 15

Same as Example 10 except that the impregnation coating amount of 4 g / m ² (2 g / m ² per side) in Example 10 was replaced with 0.4 g / m ² (0.2 g An ² per side) In this way, an ink jet recording medium of Example 15 was obtained.

Example 16.

Impregnation coating weight 4 g / m ² except that instead of the ⁽² g / m 2 per side) to 5. 5 g / m ² (per one side 2. 75 g / m ²⁾ Example 10 in Example 10 Example in the same way 16 inkjet recording media were obtained.

Example 17.

Impregnation coating weight 4 g / m ² except that instead of the ⁽² g / m 2 per side) in 6. 5 g / m ² (per one side 3. 25 g / m ²⁾ Example 10 in Example 10 In the same manner, an ink jet recording medium of Example 17 was obtained.

Example 18.

On the base paper prepared as above, boehmite alumina (average particle size 2.9 ^ m, specific surface area 2.72 m ² / g) 3% and aluminum chloride 1.5% and cationic surfactant stearyl trimethyl ammonium chloride PEM (Rebon TM-18, trade name of Sanyo Kasei Co., Ltd.) A coating solution containing 0.09% was prepared, but the viscosity of the coating solution was high, and the coating speed was extremely low. (100 m / min) to obtain the ink jet recording medium of Example 18.

Example 19.

On the base paper prepared as above, boehmite anolemina (average particle size: 2.9 m, specific surface area: 2.72 m ² / g) 3%, aluminum chloride 1.5%, and nonionic surfactant polyoxy Ethylene higher alcohol ether (Emulgen 707, trade name, manufactured by Kao Corporation) A coating solution containing 0.09% was prepared, but the viscosity of the coating solution was high, and the coating speed was extremely low. (100 m / min) The ink jet recording medium of Example 19 was obtained.

Example 20.

A coating liquid containing 3% of boehmite alumina (average particle size of 2.9 ^ m, specific surface area of 2.72 mVg) and 1.5% of aluminum chloride salt was prepared on the base paper prepared as described above. The ink-jet recording medium of Example 20 was obtained by making the viscosity of the liquid high and setting the coating speed very low (for lO OmZ).

Comparative Example 7.

On the base paper prepared as described above, boehmite alumina (average particle diameter 2.9 μιη, specific surface area 2.72 m ² / g) 3% and anionic surfactant sodium dioctyl sulfosuccinate (Sammorin OT-70 A trade name of Sanyo Kasei Co., Ltd.) A coating solution containing 0.09% was added to a dry solution of ² g / m ² to obtain a dry solid content of 4 g / m ^2. The ink jet recording medium of Comparative Example 7 was obtained by impregnation coating using a press machine and drying, followed by machine power render finishing.

Comparative Example 8.

The base paper prepared as described above contains 1.5% of aluminum chloride and 0.09% of anionic surfactant sodium octyl sulfosuccinate (Sammorin OT-70, trade name of Sanyo Chemical Co., Ltd.) The coating liquid to be applied was impregnated using a two-roll size press so that the dry solid content was 4 g / m ² , dried and then machine-rendered, followed by inkjet printing in Comparative Example 8. A recording medium was obtained.

The ink jet recording media obtained in Examples 10 to 20 and Comparative Examples 7 to 8 were evaluated from the viewpoints of print density, ink dryness, and powder drop. The results are as shown in Table 2, together with the viscosity and operability of the coating liquid used in each of the examples and comparative examples. In addition, evaluation was performed as follows.

(Print density) and (ink drying '14) are as described above.

(Viscosity)

Using a B-type rotational viscometer (VI SCOMETER, TOK IMEC INC), the viscosity at a liquid temperature of 23 was measured according to the JIS K 7117S method.

(Powdering)

The surface was rubbed with Rosa paper, and the evaluation was made based on whether or not paper dust was present.

C: Some paper dust is present, but there is no practical problem. 〇: There is no paper dust and there is no problem. (Operability)

△: Samples cannot be prepared due to paper breakage in high-speed operation. Sample production is possible at low speed operation.

'〇 ... Samples can be produced by high-speed operation.

Table 2 Coating liquid viscosity ink

Wl / I V Sonono retention ^: (mPas / 23 ° C) Drying

Rep. 10 49. 5 1 .61 O ooo Example 1 1 55. 0 1.60 O ooo Example 1 2 22.5 1 .59 O ooo Example 1 3 47, 5 1.52 O ooo Example 14 49.5 1.37 oooo Example 1 5 49.5 1.45 oooo Example 1 6 49.5 1 .63 oooo Example 1 7 49.5 1 .63 oooo o olone Example 1 8 305 1. 60 ooo Δ Example 1 9 290 1.58 oooum Example 20 267.5 1 .60 ooo Δ Comparative Example 7 6.0 1-22 o Xoo Comparative Example 8 5.5 1.45 X ooo Table 2 As is evident, in the ink jet recording medium of the present invention, both the print density and the ink drying property are good, but Examples 18 and 19, in which a surfactant other than anionic properties was added to the coating liquid, In Example 20 in which an amphoteric surfactant was not blended, the viscosity of the coating liquid was large, and the coating property at the time of high-speed coating with a 2-port size press was inferior. Also, it was confirmed that in Comparative Example 7 in which no water-soluble inorganic salt containing a metal was added, sufficient print density was not obtained, and in Comparative Example 8 in which no alumina compound was added, the ink drying property was insufficient. Was done. Industrial applicability

The ink jet recording paper obtained by the present invention is an ink jet recording paper which has a print density similar to that of a coated paper type ink jet recording paper, has no feathering, and has good ink absorbability. In addition, since the texture of plain paper is maintained, it is suitable for general writing using an electrophotographic recording method or a pencil, and is extremely significant in industry.

Claims

The scope of the claims

1. On at least one side of the base paper, a coating liquid containing an alumina compound and a water-soluble inorganic salt containing a divalent or trivalent metal ion as a main component, 0.2 to 3 g in dry solids per side Inkujetto recording sheet of plain Kamita I flop characterized by comprising a coating or impregnating such that zm ^2.

2. The plain paper-type ink jet recording paper according to claim 1, wherein the coating liquid further contains an aionic surfactant S.

3. The ink jet recording paper according to claim 1, wherein the content of the water-soluble inorganic salt is 30 to 80% by weight based on the alumina compound (anhydrous component).

4. The plain paper type inkjet recording paper according to claim 1, wherein the coating liquid contains a water-soluble film-forming resin.

5. The plain paper type ink jet recording paper according to claim 1, wherein the ink jet recording paper has a Steckigt sizing degree of 20 seconds or less.