JPH09142008A - Inkjet recording method - Google Patents

Abstract

(57) Abstract: To provide an inkjet recording method capable of obtaining a clear image by excellent miniaturization and roundness of ink dots and good absorption and fixing of recording ink to a recording medium. SOLUTION: The static contact angle between a recording medium having water repellency and a recording ink in a coating layer containing a pigment and an aqueous binder on at least one surface of a base paper is 10 or more.
From 30 degrees to 30 degrees. Furthermore, the surface tension of the recording ink is set to 2
5 to 35 mN / m. In addition, the ink composition contains glycol ethers and an acetylene glycol-based surfactant.

Description

Detailed Description of the Invention

[0001]

[0001] The present invention relates to an ink jet recording method.

[0002]

2. Description of the Related Art Conventionally, recording methods include a dot impact method, a thermal fusion transfer method, a thermal sublimation transfer method, an electrophotographic method, an ink jet method, etc. Among these methods, the ease of color recording, Inkjet methods are becoming popular because of their low cost, low running cost, quietness, and miniaturization. In particular, the inkjet method is expected to continue to play a major role as one of the recording methods since color recording can be performed at low cost.

The quality required for the ink jet recording method is that the color density and sharpness of the image are excellent. The recording medium and the image have water resistance, and the image does not bleed even if water adheres. The bleeding of the recording ink does not occur and the roundness of the ink dots is excellent. The ink dots formed on the recording medium do not spread,
It is also excellent in absorbing and fixing recording ink to the recording medium. In particular, among the above, bleeding of the recording ink does not occur and the roundness of ink dots is excellent, and It is very important in terms of full-color high image quality and high resolution to satisfy the two characteristics that the ink dots formed on the medium do not spread and the recording ink absorbs and fixes well.

Conventionally, various improved techniques have been reported for ink and recording media in order to satisfy the above quality.
In particular, many proposals have been made to improve the recording medium as well as the ink.

Recently, as one of these, a recording medium has been proposed in which a layer having water repellency is provided in or on the coating layer. When ink dots are adhered to this recording medium by an inkjet recording method, the ink repellency of the recording medium, that is, the difficulty of wetting is controlled to suppress the spread of the ink dots and form small ink dots. It aims to realize a high-resolution and clear image with small ink dots.

[0006]

However, when ink jet recording is performed using the recording medium of the above-mentioned conventional invention, immediately after the ink dots adhere to the recording medium, the ink repellent layer spreads the ink dots. Although it becomes difficult, depending on the recording ink or the recording medium, the ink does not soak into the ink receiving layer even after the ink has adhered to the recording medium, the ink dots spread slowly and irregular bleeding such as whiskers occurs, It reduces the circularity of ink dots. Further, since the recording ink is absorbed and fixed slowly, a large ink dot may be formed as a result. Also,
In the process of ejecting the recording medium, the recording ink adheres to the printer, the traces of the knurled roller are generated on the recording medium, and the recording medium printed immediately before the recording medium is ejected after the recording medium is ejected. Transfer and show-through may occur due to the recording ink of the medium, or the hand may get dirty when touched after printing is completed.

[0007] In particular, when a water-based ink containing water as a main component is used, these phenomena occur extremely remarkably under an environment of low temperature and high humidity where the ink is hard to evaporate.

The present inventors have now developed a combination of a recording medium having water repellency in a coating layer containing a pigment and an aqueous binder and having a water-repellent property, and a recording ink having specific properties. Excellent in miniaturization and roundness of ink dots, and good absorption of recording ink on the recording medium.
The present inventors have found that it is possible to achieve both fixing characteristics and obtain a sharp image unexpectedly. The present invention is based on this finding.

That is, the present invention provides an ink jet recording method capable of obtaining a clear image by excellent miniaturization and roundness of ink dots and good absorption and fixing of recording ink on a recording medium. Has an aim.

[0010]

The ink jet recording method according to the present invention is a recording material having water repellency in or on a coating layer containing a pigment and an aqueous binder on at least one surface of a base paper. Static contact angle between medium and recording ink is 1
It is characterized in that it is 0 to 30 degrees. The surface tension of the recording ink is 25 to 35 mN / m.
And the recording ink contains a glycol ether and an acetylene glycol-based surfactant.

The recording medium used in the present invention is composed of a base paper, a coating layer, and a water-repellent material, and the coating layer is composed of a pigment, an aqueous binder and the like.

The base paper is a paper with no added size or appropriately sized, and may or may not contain a filler.

Examples of pigments used in the coating layer include light calcium carbonate, heavy calcium carbonate, kaolin (white clay), talc, calcium sulfate, barium sulfate,
Titanium oxide, zinc oxide, zinc sulfide, zinc carbonate, aluminum silicate, diatomaceous earth, calcium silicate, magnesium silicate, synthetic amorphous silica, aluminum hydroxide,
There are white pigments such as alumina, styrene plastic pigments, acrylic plastic pigments, microcapsules, and urea resin pigments.

As the water-based binder, for example, oxidized starch,
Etherified starch, cellulose derivatives such as carboxymethyl cellulose, hydroxyethyl cellulose, casein, gelatin, soybean protein, polyvinyl alcohol and its derivatives, maleic anhydride resin, ordinary styrene-
Butadiene copolymer, conjugated diene polymer latex such as methyl methacrylate-butadiene copolymer, acrylic polymer latex such as polymer or copolymer of acrylic acid ester and methacrylic acid ester, ethylene vinyl acetate copolymer, etc. Vinyl polymer latex, or functional group-modified polymer latex with a functional group-containing monomer such as carboxyl group of these various polymers, melamine resin, water-based adhesive such as thermosetting synthetic resin system of urea resin, Also, synthetic resin adhesives such as polymethylmethacrylate, polyurethane resin, unsaturated polyester resin, vinyl chloride-vinyl acetate copolymer, and polyvinyl butyral are used alone or in combination.

It is also possible to add a cationic resin, a cationic surfactant, cationic modified inorganic fine particles and the like as a water resistance agent to the coating layer.

Further, if necessary, a pigment dispersant, a thickener, a fluidity improver, an antifoaming agent, a foam suppressor, a release agent, a foaming agent, a penetrating agent,
A coloring pigment, a coloring dye, a fluorescent brightener, an ultraviolet absorber, an antioxidant, a preservative, and the like can be appropriately compounded.

As the water repellent material, a fluorine-based surfactant,
Examples include water-soluble silicone compounds or silicone emulsions, fluorine-containing synthetic amorphous silica, and aliphatic hydrocarbon compounds. These water-repellent materials may be contained in the coating layer, may be directly coated on the coating layer formed on the base paper, or those containing a water-based binder etc. may be coated. You can apply it on top.

The fluorinated surfactants include anion-based, cation-based and nonionic fluorinated surfactants such as fluorine-substituted alkyl esters and perfluoroalkylcarboxylates (eg, Neos Co., Ltd. Futgent series, Ciba-Geigy Rhodyne series, DuPont Zonil series, ICI Montfloor series, Asahi Glass Co., Ltd. Surflon series, Daikin Industries Co., Ltd. Unidyne series, or Sumitomo 3M FC series).

As the water-soluble silicone compound, a polyalkyl or polyallyl siloxane (eg, dimethyl siloxane, finyl siloxane, etc.) and a high alcohol (eg, ethylene glycol, trimethylol propane, pentaerythritol, sorbitol, etc.) are randomly selected. , Block or graft copolymers which are water-soluble. Further, a water-soluble copolymer of a siloxane compound and hydroxymethacrylic acid is also a preferred example. The silicone compound may be in the form of a silicone emulsion, specifically, an emulsion in which silicone oil (polydimethylsiloxane having a siloxane skeleton (Si-O-Si)) is stably dispersed in water, or dimethylsiloxane. The thing obtained by emulsion-polymerizing a monomer is mentioned. Some of the methyl groups in these molecules may be substituted with epoxy groups, amino groups, reactive hydrogen, and the like.

As the fluorine-containing amorphous silica, sodium fluoride, hydrofluoric acid, hydrogen fluoride gas, silicon tetrafluoride, etc. may be added or contacted in the vapor phase phase or the like after the production or production of the synthetic amorphous silica. Can be formed by reacting with.

The aliphatic hydrocarbon compounds include petroleum waxes such as paraffin wax and microcrystalline wax, natural waxes such as beeswax and carnauba wax,
Fatty acids such as stearic acid, myristic acid and oleic acid, metal soaps such as calcium stearate and zinc stearate, fatty acid chromium complex salts such as stearic acid chromic chloride complex salts and myristic acid chromic chloride complex salts, alkyd resins, polyester resins such as maleic acid resins , Polyethylene emulsion and the like. Among these, stearic acid salt compounds such as calcium stearate and zinc stearate are particularly effective.

Preferable specific examples of such a recording medium are Japanese Patent Laid-Open Nos. 3-24908 and 4-26.
Recording media described in JP-A-5784, JP-A-7-96654, and JP-B-7-67852 can be cited.

The recording ink used in the present invention is
It is composed of a colorant, an organic solvent and the like.

Preferred examples of colorants include direct dyes,
Acid dyes, food dyes, basic dyes, reactive dyes, disperse dyes, architectural dyes, soluble architectural dyes, reactive disperse dyes, oil-based dyes can all be used, and among them, water-soluble dyes are preferable from the viewpoint of recording liquid performance. Used and particularly preferred is C.I. I. Direct Red 2, 4, 9, 23, 2
6, 31, 39, 62, 63, 72, 75, 76, 7
9, 80, 81, 83, 84, 89, 92, 95, 11
1, 173, 184, 207, 211, 212, 21
4, 218, 221, 223, 224, 225, 22
6, 227, 232, 233, 240, 241, 24
2, 243, 247, C.I. I. Direct Violet 7, 9, 47, 48, 51, 66, 90, 93, 94,
95, 98, 100, 101, C.I. I. Direct Yellow 8, 9, 11, 12, 27, 28, 29, 33, 3
5, 39, 41, 44, 50, 53, 58, 59, 6
8, 86, 87, 93, 95, 96, 98, 100, 1,
06, 108, 109, 110, 130, 132, 14
2, 144, 161, 163, C.I. I. Direct Blue 1, 10, 15, 22, 25, 55, 67, 68, 7
1, 76, 77, 78, 80, 84, 86, 87, 9
0, 98, 106, 108, 109, 151, 156,
158, 159, 160, 168, 189, 192, 1
93, 194, 199, 200, 201, 202, 20
3, 207, 211, 213, 214, 218, 22
5,229,236,237,244,248,24
9, 251, 252, 264, 270, 280, 28
8, 289, 291, C.I. I. Direct Black 9,
17, 19, 22, 32, 51, 56, 62, 69, 7
7, 80, 91, 94, 97, 108, 112, 11
3, 114, 117, 118, 121, 122, 12
5, 132, 146, 154, 166, 168, 17
3, 199, C.I. I. Acid Red 35, 42, 5
2, 57, 62, 80, 82, 111, 114, 11
8, 119, 127, 128, 131, 143, 15
1, 154, 158, 249, 254, 257, 26
1, 263, 266, 289, 299, 301, 30
5, 336, 337, 361, 396, 397 C.I. I. Acid Violet 5, 34, 43, 47,
48, 90, 103, 126, C.I. I. Acid Yellow 17, 19, 23, 25, 39, 40, 42, 44,
49, 50, 61, 64, 76, 79, 110, 12
7, 135, 143, 151, 159, 169, 17
4, 190, 195, 196, 197, 199, 21
6, 219, 222, 227, C.I. I. Acid Blue 9, 26, 40, 41, 62, 72, 76, 78, 8
0, 82, 92, 106, 112, 113, 120, 1
27, 129, 138, 143, 175, 181, 20
5, 207, 220, 221, 230, 232, 24
7, 258, 260, 264, 271, 277, 27
8, 279, 280, 288, 290, 326, C.I.
I. Acid Black 7, 24, 29, 48, 52, 1
72 C. I. Reactive Red 3, 13, 17, 19, 2
1, 22, 23, 24, 29, 35, 37, 40, 4
1, 43, 45, 49, 55, C.I. I. Reactive Violet 1, 3, 4, 5, 6, 7, 8, 9, 16, 1
7, 22, 23, 24, 26, 27, 33, 34, C.I.
I. Reactive Yellow 2, 3, 13, 14, 15,
17, 18, 23, 24, 25, 26, 27, 29, 3
5, 37, 41, 42, C.I. I. Reactive Blue 2, 3, 5, 8, 10, 13, 14, 15, 17, 1
8, 19, 21, 25, 26, 27, 28, 29, 3
8, C.I. I. Reactive Black 4, 5, 8, 14,
21, 23, 26, 31, 32, 34, C.I. I. Basic Red 12, 13, 14, 15, 18, 22, 2
3, 24, 25, 27, 29, 35, 36, 38, 3
9, 45, 46, C.I. I. Basic violet 1,
2, 3, 7, 10, 15, 16, 20, 21, 25, 2
7, 28, 35, 37, 39, 40, 48, C.I. I. Basic Yellow 1, 2, 4, 11, 13, 14, 1
5, 19, 21, 23, 24, 25, 28, 29, 3
2, 36, 39, 40, C.I. I. Basic Blue 1,
3, 5, 7, 9, 22, 26, 41, 45, 46, 4
7, 54, 57, 60, 62, 65, 66, 69, 7
1, C.I. I. Basic Black 8 and the like.

The additive for these dyes is determined depending on the type of dye, the type of solvent component, the properties required for the ink, etc., but generally 0.2% to the total weight of the ink.
The range is preferably from 15 to 15 wt%, more preferably from 0.5 to 10 wt%.

Preferred examples of the organic solvent include high boiling point and low volatility polyhydric alcohols such as glycerin, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, hexylene glycol, polyethylene glycol and polypropylene glycol. Is used, and other N methyl 2
-Pyrrolidone, 1,3-dimethylimidazolidinone, monoethanolamine, N, N-dimethylethanolamine, N, N-dimethylethanolamine, diethanolamine, Nn-butyldiethanolamine, triisopropanolamine, triethanolamine, etc. A water-soluble organic solvent such as a nitrogen organic solvent can be added within a range that does not cause bleeding in printing. In particular, diethylene glycol, glycerin and the like are preferable, and according to a preferable aspect of the present invention, it is preferable that the ink composition further contains benzotriazole from the viewpoint of stabilizing the physical properties of the ink.

Examples of preferable surfactants and penetrants include anionic surfactants, amphoteric surfactants, cationic surfactants and nonionic surfactants. Alkylsulfocarboxylate as anionic surfactant,
α-olefin sulfonate, polyoxyethylene alkyl ether acetate, N-acyl amino acid and its salt, N-acyl methyl taurine salt, alkyl sulfate polyoxyalkyl ether sulfate, alkyl sulfate polyoxyethylene alkyl ether phosphate , Rosin acid soap,
Castor oil sulfuric acid ester salt, lauryl alcohol sulfuric acid ester salt, alkylphenol type phosphoric acid ester, alkyl type phosphoric acid ester, alkylallylsulfone hydrochloric acid, diethylsulfosuccinate, diethylhexylsylsulfosuccinate dioctylsulfosuccinate and the like can be mentioned. As the cationic surfactant, 2-vinylpyridine derivative, poly-4-
Examples include vinyl pyridine derivatives. Examples of the amphoteric surfactant include lauryl dimethylamino acetate betaine, 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine, coconut oil fatty acid amide propyldimethylamino acetate betaine, polyoctyl polyaminoethyl glycine, and other imidazoline derivatives. is there. Nonionic surfactants include polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene dodecyl phenyl ether, polyoxyethyl octyl phenyl ether, polyoxyethylene oleyl ether, polyoxyethylene lauryl ether, polyoxy Ether type such as ethylene alkyl ether, polyoxyallyl alkyl ether, polyoxyethylene oleic acid, polyoxyethylene oleic acid ester, polyoxyethylene distearate ester, sorbitan laurate, sorbitan monostearate, sorbitan monooleate, sorbitan Esters such as sesquioleate, polyoxyethylene monooleate, polyoxyethylene stearate, 2, 4, 7 9-tetramethyl-5-decyne -4,
7-diol, 3,6-dimethyl-4-octyne-3,
Acetylene glycols such as 6-diol and 3,5-dimethyl-1-hexyne-3-ol (for example, Surfinol 104, 82, 465, Olfine STG manufactured by Nissin Chemical Co., Ltd.), the above-mentioned fluorine-based surfactants, etc. Is mentioned.

[0028] One of the objects of the present invention is to achieve both excellent miniaturization and roundness of ink dots and good absorption / fixing characteristics of recording ink on a recording medium. The possible recording method is possible by using an appropriate recording medium and recording ink with the above-mentioned configuration.

By setting the static contact angle to 10 degrees or more, the water-repellent layer of the recording medium can suppress the spread of ink dots, and small dots can be formed on the recording medium. The static contact angle is 30
When the degree is less than the range, good absorption and fixing characteristics of the recording ink can be obtained with respect to the recording medium having water repellency, and ink dots having excellent roundness can be formed on the recording medium.

That is, when the static contact angle between the recording medium having water repellency in the coating layer or on the coating layer and the recording ink is 10 degrees or more and 30 degrees or less, the ink dots become fine and good. It is possible to achieve both good circularity and good absorption / fixing characteristics of the recording ink on the recording medium.

Further, the surface tension of the recording ink is adjusted to 25 to 35.
By setting mN / m, it is possible to enhance the permeability of the ink to the recording medium having water repellency and to obtain excellent absorption and fixing characteristics of the recording ink to the recording medium. The surface tension of the recording ink can be adjusted within the above range by appropriately adding the surfactant to prepare the recording ink.

A recording ink containing a glycol ether and an acetylene glycol-based surfactant is most preferable for achieving the above surface tension.

The amount of glycol ether added is 5 to 2
A range of 0 part is preferred. The addition amount of the acetylene glycol-based surfactant is preferably in the range of 0.1 to 3 parts.

In the ink jet recording method according to the present invention, ink particles are ejected onto the recording medium and ink dots are formed on the recording medium, except that the recording ink and the recording medium are used. In this respect, it is common with the general inkjet recording method. According to a preferred embodiment of the present invention, the amount of recording ink absorbed by the recording medium is 3 × 10 ⁵ to 3 × 10 ⁶ pl / cm ² . The amount of recording ink absorbed here means that the recording ink does not overflow on the recording medium to obtain a proper printing state, and the recording ink does not strike through to the back side of the recording medium. Indicates the amount of recording ink in the state.

According to the ink jet recording method of the present invention, it is possible to achieve both the miniaturization and good circularity of ink dots and the good absorption and fixing characteristics of the recording ink on the recording medium, which are contradictory characteristics. . As a result,
An extremely sharp or sharp high resolution image is obtained.

Although not intending to be bound by the following theory, the reason why fine and good circularity of ink dots and good absorption / fixing characteristics of recording ink on a recording medium can be obtained. Will be described with reference to FIG. FIG. 1A is a diagram showing the formation of ink dots by the recording method according to the present invention. First, the recording ink particles 1 ejected from a recording head nozzle (not shown) adhere to the highly ink-repellent layer 3 provided on the surface of the recording medium 2. Due to the high ink repellency of the layer 3, the recording ink particles 1 are absorbed on the recording medium 2 without spreading so much and reach the base material 4 such as paper. The ink dot 5 obtained as a result has a relatively small dot diameter. Here, when the contact angle between the recording ink and the recording medium is smaller than the above range as shown in FIG. 1B, extremely large ink dots 6 are formed. When the contact angle between the recording ink and the recording medium is larger than the above range as shown in FIG. 1C, the contact area between the ink dot 7 and the recording medium is small, and therefore the recording ink is recorded on the recording medium. Does not easily penetrate, and as a result, the recording ink does not dry, and the recording medium is soiled or the hand is soiled when the recording medium is touched. Also, the absorption of recording ink on the recording medium
Since the fixing is slow, the spread of the ink dots progresses, the ink dots bleed, and the roundness is greatly reduced.

[0037]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be further explained by the following examples, but the present invention is not limited to these examples.

<Preparation of Recording Ink> (Recording Ink 1) Recording Ink 1 was prepared by mixing and heating the following components and stirring well. C. I. Direct Blue 199 4 parts Surfynol 465 (manufactured by Nissin Chemical Co., Ltd.) 1 part Triethylene glycol monobutyl ether 10 parts Diethylene glycol 16 parts Pure water 69 parts (Recording Ink 2) Mix and heat the following ingredients and stir well Recording ink 2 was prepared. C. I. Direct Yellow 86 2 parts Surfynol 465 0.7 parts Triethylene glycol monobutyl ether 10 parts Diethylene glycol 17 parts Pure water 70.3 parts (Recording ink 3) Recording ink 3 is prepared by mixing and heating the following components and stirring well. Was prepared. C. I. Acid Red 52 2.5 parts Surfynol 465 0.5 parts Triethylene glycol monobutyl ether 10 parts Diethylene glycol 16.5 parts Pure water 70.5 parts (Recording Ink 4) Other than not adding Surfynol 465 to Recording Ink 1. Recording Ink 4 was prepared in the same manner as Recording Ink 1.

<Preparation of Recording Medium> (Recording Medium 1) For 100 parts of synthetic amorphous silica, P
A coating solution was prepared by adding 150 parts of a 10% VA aqueous solution and further adding 1% by weight of a silicone / ethylene glycol copolymer to the aqueous solution. 60 g / m2 of this coating liquid
Recording medium 1 was obtained by coating the above high-quality paper with a solid content of 20 g / m 2 with a wire bar.

(Recording Medium 2) Synthetic Amorphous Silica 100
A coating solution containing 20 parts of PVA and having a concentration of 15% was prepared. This coating solution was applied to a high-quality paper of 90 g / m 2 in an amount of 15 g / m 2 with a wire bar to prepare a base paper.

Further, 90 parts of synthetic amorphous silica, 10 parts of fluorine-containing synthetic amorphous silica and 40 parts of PVA were added and mixed to obtain a coating liquid having a concentration of 15%. This coating solution was coated on the above-mentioned base paper so as to have a solid content of 6 g / m @ 2 to obtain a recording medium 2.

(Recording Medium 3) JP-A-7-696654
The recording medium described in Example 1 of the publication is referred to as recording medium 3.

(Recording medium 4) Recording medium 4 was obtained by the same method as that of recording medium 1, except that recording medium 1 was prepared without adding the silicone-ethylene glycol copolymer.

(Recording Medium 5) Copy paper manufactured by Fuji Xerox Co., Ltd. was used as the recording medium 5.

The following printing test was conducted using the above recording ink and recording medium.

Printing Test 1 <Dot Diameter> For the recording inks 1 to 4 and the recording media 1 to 5, an inkjet printer MJ-900C (manufactured by Seiko Epson Corporation) was used to absorb the recording inks into the recording media. Printing was performed so that the amount was 5 × 10 5 pl / m 2.

Here, the case where the ink dot and the adjacent ink dot are in contact with each other is marked with x, and the case where they are not in contact is marked with ◯.

Printing Test 2 <Roundness> Using the same printer as in Printing Test 1, printing was performed using the recording ink and recording medium used in Printing Test 1.
Then, the roundness of the formed ink dots was obtained according to the following formula. Roundness = 4πS / (L2) (where S: dot area, L: dot circumference) The roundness thus determined was evaluated according to the following criteria. The roundness is 1.0 or less 0.9 or more-excellent (◯) 0.9 or less 0.8 or more-slightly poor (Δ) less than 0.8-poor (x).

Printing Test 3 <Absorption / Fixability> Using the same printer as in Printing Test 1, characters and solid prints were made using the recording ink and recording medium used in Printing Test 1, and the printing medium was printed from the printer. Immediately after the paper was discharged, the characters and solid parts were rubbed with a finger to indicate that the stain was ○, the case where the stain was faint was marked as △, and the stain was marked when the stain could be visually confirmed.

Printing test 4 <Print stain> Using the same printer as in printing test 1, using the recording ink and recording medium used in printing test 1, characters were printed under the environment of temperature 10 ° C. and humidity 80% RH. Solid printing is performed continuously on two sheets, and when there is no transfer / offset of the first recording ink on the second recording medium, it is indicated by ◯, and when dirty by transfer / offset, it is indicated by X.

Table 1 shows the results of the above printing tests 1 to 4.

[0052]

[Table 1]

[0053]

EFFECT OF THE INVENTION A static contact angle between a coating layer containing a pigment and an aqueous binder on at least one side of a base paper or a recording medium having water repellency on the coating layer and a recording ink is 10 degrees. By using the ink jet recording method characterized by being from 30 degrees to 30 degrees, it is possible to obtain contradictory characteristics such as miniaturization of ink dots and good roundness, and good absorption and fixing characteristics of recording ink on a recording medium. It can be compatible.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating formation of ink dots on a recording medium. (A) is a diagram showing the formation of ink dots by the inkjet recording method according to the present invention, (B) is a diagram showing the formation of ink dots when the contact angle between the recording medium and the recording ink is small, (C) FIG. 9 is a diagram showing formation of ink dots when the contact angle between the recording medium and the recording ink is large.

[Explanation of symbols]

 1 recording ink particles 2 recording medium

Claims (3)

[Claims] 1. A static contact angle between a recording medium having water repellency and a recording ink in or on a coating layer containing a pigment and an aqueous binder on at least one surface of a base paper is 10.
An ink jet recording method, wherein the ink jet recording method is about 30 degrees. 2. The surface tension of the recording ink is 25 to 35.
The ink jet recording method according to claim 1, wherein the ink jet recording method is mN / m. 3. The ink jet recording method according to claim 1, wherein the recording ink contains a glycol ether and an acetylene glycol-based surfactant.