JP2010173287A - Recording method, clear ink, ink, and media - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ideal inkjet recording method by which a high quality image can be obtained, strong gloss near a silver salt photograph can be easily reproduced, and excellent abrasion resistance of a printed matter can be attained. <P>SOLUTION: The inkjet recording method includes an image forming step and a posttreatment step. In the image forming process, ink containing a particulate color material, a fluoro-surfactant and water and having solid content of 6 mass% or more is made to fly onto a medium comprising at least one coating layer containing inorganic pigment and an SBR (styrene butadiene rubber) resin on at least one surface of a support composed essentially of cellulose pulp. In the posttreatment step, clear ink containing a resin particulate and water and having solid content of 10 mass% or more is applied onto the medium after image formation. Ink absorption amount into the medium at 500 ms contact time is 1 to 10 ml/m<SP>2</SP>when measured by a scanning absorptometer meter. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a recording method capable of recording an image having high gloss and high abrasion resistance on a commercial printing paper such as an offset printing paper by an inkjet method, and a clear ink, an ink, and a medium used in the recording method .

  The ink jet recording method is known as an excellent recording method that can be easily colored and has a low running cost, and includes a recording device, a recording method, ink, a recording material (referred to as a medium, and so on). Research and development is actively conducted. In particular, with respect to media, ink-jet media that are broadly classified into swelling types and void types have been developed, and recently, void types that are excellent in ink drying speed have become mainstream.

  This void-type ink-jet medium has a configuration in which an ink absorbing layer having a void for taking in ink on a support and, if necessary, a porous gloss layer are provided. With this characteristic configuration, the ink absorbability is extremely excellent, and it has a glossiness and a quality feeling that surpasses conventional silver salt photography, and a high-definition output can be obtained. On the other hand, void-type ink-jet media can maintain high transparency as a filler constituting the ink absorption layer, and it is necessary to use a material with a large oil absorption (specific surface area). In particular, it is necessary to use a large amount of specific expensive fillers such as materials and colloidal silica, and it is very difficult to reduce the price. In addition, void-type ink jet media are very expensive compared to conventional silver salt photographic printing paper because the manufacturing process is complicated.

  Further, as a disadvantage of the ink jet recording method, there is a point that the image is easily damaged as compared with a silver salt photographic printing paper. In the case of silver salt photographic printing paper, the color-developing layer is in the middle layer of the photographic paper and the surface is protected by a transparent gelatin layer. On the other hand, in the case of ink jet media, the position of the color material that forms an image is close to the surface of the ink jet media due to process limitations, and therefore it is difficult to obtain image reliability (abrasion resistance) comparable to silver salt photographs. In this regard, if the dye material is easy to permeate into the inkjet media, the pigment material is often present on the outermost layer of the inkjet media, and it is difficult to obtain abrasion resistance. is the current situation.

  In recent years, inkjet recording methods are not limited to consumer use, but can be applied to variable prints that change the printing contents for each distribution target, such as the issuance of a small number of copies and commercial-based photographic printing fields such as DPE. Although desirable, due to these drawbacks, cost requirements and image reliability requirements cannot be satisfied, and the images are not used much despite their high quality.

  On the other hand, in the offset printing method in which a new oil-based ink is used, there is a very inexpensive medium such as a cast coated paper having a high gloss surface such as a photographic paper for silver salt photography, which is preferably used in the commercial printing field. ing. This is because the material constituting the coating layer of the cast coated paper is very inexpensive, and the production method is simpler than that of the ink jet medium, and the productivity is high. However, these media are usually designed on the assumption that images are formed using offset printing. When printing with the conventional inkjet method, the ink is not absorbed and the image is blurred or dried. It is not practical at all, such as having a long time. In addition, since it does not contain a cation fixing material, there is no image reliability, it bleeds with water, fades with ozone, the color material tends to stay on the surface layer of the media, and of course the color material can be damaged by some friction. Peeling off, discoloration, and color transfer occur.

  On the other hand, attempts have been made to reproduce silver salt photographs using an ink jet recording method in which clear ink and ink containing a colorant are combined. Patent Document 1 discloses a recording method in which inkjet recording is performed on a dedicated inkjet paper or plain paper using pigment ink and clear ink. However, this method cannot realize image gloss and abrasion resistance comparable to silver salt photography.

  Patent Document 2 discloses an emulsion composition for clear ink, but this technique discloses an emulsion that does not cause kogation and is difficult to precipitate, and is suitable for a so-called inkjet thermal head. It's not a technology to improve.

  For these reasons, it is possible to realize high-gloss prints such as silver salt photographs at low cost by the inkjet method, particularly to achieve high-gloss images using inexpensive media and pigment inks such as cast-coated paper for commercial printing. It has been considered very difficult.

JP 2003-266932 A Special table 2007-521356

  The present invention has been made in order to solve the following problems in view of the above results. That is, the object of the present invention is to form an image on paper with poor ink absorption, such as cast-coated paper for commercial printing, to have good image quality, and to easily obtain a strong gloss similar to a silver salt photograph. The present invention provides an ideal ink jet recording method that can be reproduced and has excellent abrasion resistance of printed matter.

The recording method of the present invention provides a medium comprising a coating layer containing at least one inorganic pigment and a styrene-butadiene copolymer on at least one surface of a support mainly composed of cellulose pulp. An image forming process for forming an image by flying an ink having a solid content of 6% by mass or more containing a particulate colorant, a surfactant, and water, and a resin after forming the image contains resin fine particles and water. And a post-processing step of applying a clear ink having a solid content of 10% by mass or more, wherein the ink absorption amount with respect to the medium at a contact time of 500 ms by a scanning absorption meter is 1 ml / m ² or more and 10 ml / m ² or less.
In this case, it is preferable that the adhesion amount of the clear ink is 0.3 g / m ² or more and 5 g / m ² or less by dry weight.
In this case, it is preferable that two types of clear ink are provided and applied while changing the usage rate of the clear ink in accordance with the background gloss of the medium in the post-processing step.
In this case, it is preferable that the 60 ° glossiness defined in JIS-ZS-8741 of the media is 50% or more.
In this case, the surfactant is preferably a fluorinated surfactant.
The clear ink of the present invention is a clear ink used in the recording method, characterized by containing 20% by mass or more of a wetting agent and having a viscosity at 25 ° C. of 5 mPa · s to 30 mPa · s. .
In this case, it is preferable that the surfactant is included and the surface tension at 25 ° C. is 15 to 30 mN / m.
The ink of the present invention is an ink used in the recording method.
The medium of the present invention is a medium used in the recording method.

  As will be apparent from the following detailed and specific description, according to the present invention, the print quality is good, high reliability, and high gloss are achieved, while the disadvantages of the conventional inkjet recorded matter are low. There is an extremely excellent effect that the cost can be reduced.

  The present inventor has conducted earnest research on a low-cost, high-speed and high-reliability ink-jet recording method capable of realizing silver salt photographic image quality, and has a glossy surface, in particular, a high surface gloss and high ink permeability. In combination with low penetrability inks (meaning colored inks, the same applies hereinafter) and clear inks (meaning colorless inks, and so on), a new design concept Based on this, a low-cost and on-demand recording method has been invented. Hereinafter, embodiments of the present invention will be described in detail.

<Ink>
The ink of the present embodiment was invented in view of its suitability for a medium with low ink absorbency, and has excellent wettability because of its lower surface tension than ordinary inkjet inks, and is a medium with less ink penetration. In contrast, the ink has a characteristic that the permeability of the carrier is strong and the ink viscosity is greatly increased only by the penetration of a small amount of carrier. For this reason, conventionally, it is difficult to fuse with adjacent dots after landing even for media with poor absorbability where adjacent dots are easily fused, and stable dot formation is possible. Furthermore, since the color material hardly penetrates into the medium and remains on the surface, the color material is excellent in color development efficiency, and sufficient color development and image density can be obtained even with a very small amount of ink. In this way, drawing is performed in a form in which the total amount of ink is significantly suppressed as compared with the conventional case, so that the amount of ink to be penetrated into the medium can be reduced, and the drying property is greatly improved.

  The ink of this embodiment contains at least water, a particulate coloring material, and a surfactant, and further contains a coloring agent fixing agent, a penetrating agent, a wetting agent, and other components as necessary. It becomes.

-Particulate color material-
There is no restriction | limiting in particular as coloring of the ink of this embodiment, It can color suitably in yellow, magenta, cyan, black, etc. using a particulate color material. The particulate color material used in the ink of the present embodiment is not particularly limited, but it is preferable to use at least one of a pigment and colored fine particles.

  As the colored fine particles, an aqueous dispersion of fine polymer particles containing at least one colorant of pigment and dye is preferably used. Here, the term “containing a color material” means either or both of a state in which the color material is enclosed in the polymer fine particles and a state in which the color material is adsorbed on the surface of the polymer fine particles. In this case, it is not necessary for all of the color material blended in the ink of the present embodiment to be enclosed or adsorbed in the polymer fine particles, and the color material is dispersed in the emulsion as long as the effects of the present invention are not impaired. May be. The coloring material is not particularly limited as long as it is water-insoluble or hardly water-soluble and can be adsorbed by the polymer, and examples thereof include water-soluble dyes, oil-soluble dyes, dyes such as disperse dyes, pigments, and the like. However, oil-soluble dyes and disperse dyes are preferable from the viewpoints of good adsorptivity and encapsulation, and pigments are preferably used from the light resistance of the resulting image. Here, the “water-insoluble or hardly water-soluble” means that the coloring material does not dissolve 10 parts by mass or more with respect to 100 parts by mass of water at 20 ° C. Further, “dissolve” means that separation or sedimentation of the coloring material is not observed in the surface layer or the lower layer of the aqueous solution visually. In addition, from the viewpoint of efficiently impregnating the polymer fine particles, each of the dyes is preferably dissolved in an organic solvent, for example, a ketone solvent in an amount of 2 g / liter or more, and more preferably 20 to 600 g / liter. The water-soluble dye is a dye classified into an acid dye, a direct dye, a basic dye, a reactive dye, and a food dye in the color index, and preferably has excellent water resistance and light resistance. .

  The volume average particle diameter of the polymer fine particles (colored fine particles) containing the colorant is preferably 0.01 to 0.16 μm in the ink. If it is less than 0.01 μm, the bleeding of the fine particles tends to flow and the light resistance becomes inferior. On the other hand, if it exceeds 0.16 μm, the nozzle is likely to be clogged or the color developability is deteriorated.

  When a pigment is used as the particulate colorant, self that can be stably dispersed without using a dispersant in which at least one hydrophilic group is bonded to the surface of the pigment directly or via another atomic group Dispersed pigments can be used. In this case, as the self-dispersing pigment, those having ionicity are preferable, and those having an anionic charge are particularly preferable.

Examples of the anionic hydrophilic group, for _{example, -COOM, -SO 3 M, -PO} 3 HM, -PO 3 M 2, -SO 2 NH 2, -SO 2 NHCOR ( although, M in the formula is hydrogen An atom, an alkali metal, ammonium, or organic ammonium is represented, and R represents an alkyl group having 1 to 12 carbon atoms, an optionally substituted phenyl group, or an optionally substituted naphthyl group. Etc. Among these, it is preferable to use those in which —COOM and —SO ₃ M are bonded to the surface of the color pigment.

  Further, “M” in the hydrophilic group includes, for example, lithium, sodium, potassium and the like as an alkali metal. Examples of the organic ammonium include mono to trimethyl ammonium, mono to triethyl ammonium, and mono to trimethanol ammonium. As a method of obtaining the anionically charged color pigment, as a method of introducing —COONa to the color pigment surface, for example, a method of oxidizing the color pigment with sodium hypochlorite, a method of sulfonation, a diazonium salt The method of making it react is mentioned. The volume average particle diameter of the self-dispersing pigment is preferably 0.01 to 0.16 μm in the ink.

  Further, when a pigment is used as the particulate color material, a pigment dispersion using a pigment dispersant can also be used. As the pigment dispersant, as a hydrophilic polymer compound, in a natural system, a vegetable polymer such as gum arabic, tragan gum, guar gum, karaya gum, locust bean gum, arabinogalactone, pectin, quince seed starch, alginic acid, Examples include seaweed polymers such as carrageenan and agar, animal polymers such as gelatin, casein, albumin and collagen, and microbial polymers such as xanthene gum and dextran.

  In semi-synthetic systems, fiber polymers such as methylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, carboxymethylcellulose, starch polymers such as sodium starch glycolate and sodium starch phosphate, sodium alginate, propylene glycol alginate And seaweed polymers such as

  Pure synthetic systems include polyvinyl polymers such as polyvinyl alcohol, polyvinyl pyrrolidone, and polyvinyl methyl ether, non-crosslinked polyacrylamide, polyacrylic acid or alkali metal salts thereof, acrylic resins such as water-soluble styrene acrylic resins, and water-soluble styrene malees. Acid resin, water-soluble vinyl naphthalene acrylic resin, water-soluble vinyl naphthalene maleic resin, polyvinyl pyrrolidone, polyvinyl alcohol, alkali metal salt of β-naphthalene sulfonic acid formalin condensate, cationic functional group such as quaternary ammonium and amino group Examples thereof include a polymer compound having a salt in the side chain and a natural polymer compound such as shellac.

  Among these, those having a carboxyl group introduced from a homopolymer of acrylic acid, methacrylic acid or styrene acrylic acid or a copolymer of a monomer having another hydrophilic group are particularly preferred as the polymer dispersant.

  The weight average molecular weight of the copolymer is preferably 3,000 to 50,000, more preferably 5,000 to 30,000, and still more preferably 7,000 to 15,000. The mixing mass ratio of the pigment and the dispersant is preferably in the range of 1: 0.06 to 1: 3, and more preferably in the range of 1: 0.125 to 1: 3.

  Examples of the pigment used in the particulate color material of the present embodiment include black or color inorganic pigments and organic pigments. These may be used individually by 1 type and may use 2 or more types together.

  Inorganic pigments include titanium oxide and iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, and chrome yellow, as well as carbon produced by known methods such as the contact method, furnace method, and thermal method. Black can be used.

  Organic pigments include azo pigments (including azo lakes, insoluble azo pigments, condensed azo pigments, chelate azo pigments), polycyclic pigments (eg, phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazines). Pigments, indigo pigments, thioindigo pigments, isoindolinone pigments, quinofullerone pigments, etc.), dye chelates (for example, basic dye type chelates, acidic dye type chelates), nitro pigments, nitroso pigments, aniline black, and the like can be used. Of these pigments, those having good affinity with water are particularly preferably used.

  Specific examples of pigments that are more preferably used in the above-mentioned pigments include black for carbon black (CI pigment black 7) such as furnace black, lamp black, acetylene black, channel black, or copper, iron. (CI pigment black 11), metals such as titanium oxide, and organic pigments such as aniline black (CI pigment black 1).

  Further, for color use, C.I. I. Pigment Yellow 1, 3, 12, 13, 14, 17, 24, 34, 35, 37, 42 (yellow iron oxide), 53, 55, 74, 81, 83, 95, 97, 98, 100, 101, 104 , 408, 109, 110, 117, 120, 128, 138, 150, 151, 153, 183, C.I. I. Pigment orange 5, 13, 16, 17, 36, 43, 51, C.I. I. Pigment Red 1, 2, 3, 5, 17, 22, 23, 31, 38, 48: 2, 48: 2 (Permanent Red 2B (Ca)), 48: 3, 48: 4, 49: 1, 52: 2, 53: 1, 57: 1 (Brilliant Carmine 6B), 60: 1, 63: 1, 63: 2, 64: 1, 81, 83, 88, 101 (Bengara), 104, 105, 106, 108 ( Cadmium red), 112, 114, 122 (quinacridone magenta), 123, 146, 149, 166, 168, 170, 172, 177, 178, 179, 185, 190, 193, 209, 219, C.I. I. Pigment violet 1 (rhodamine lake), 3, 5: 1, 16, 19, 23, 38, C.I. I. Pigment green 1, 4, 7, 8, 10, 17, 18, 36, and the like.

  When a cyan color material is used, it is preferably a color material having a phthalocyanine structure. I. Pigment Blue 1, 2, 3, 15 (copper phthalocyanine blue R), 15: 1, 15: 2, 15: 3 (phthalocyanine blue G), 15: 4, 15: 6 (phthalocyanine blue E), 15:34, 16, 17: 1, 22, 56, 60, 63, C.I. I. Bat Blue 4, 60 and the like. In particular, phthalocyanine blue 15: 3 is desirable from the viewpoint of cost and safety.

  The added amount of the particulate color material used in the ink of the present embodiment in the ink is preferably 2 to 15% by mass, and more preferably 3 to 12% by mass. When the addition amount is less than 2% by mass, the image density may be lowered due to a decrease in coloring power, or feathering or bleeding may be deteriorated due to a decrease in viscosity. If the nozzle is left unattended, the nozzles will be easy to dry, non-ejection phenomenon will occur, the viscosity will be too high, the permeability will decrease, and the dots will not spread, so the image density will decrease. Or a blurred image.

-Surfactant-
The surfactant used in the ink of the present embodiment is not particularly limited and can be appropriately selected depending on the purpose. For example, an anionic surfactant, a nonionic surfactant, an amphoteric surfactant, a nonionic surfactant Surfactant, acetylene glycol surfactant, or fluorosurfactant may be mentioned. Examples of the anionic surfactant include polyoxyethylene alkyl ether acetate, dodecylbenzene sulfonate, and laurate. And salts of polyoxyethylene alkyl ether sulfate.

  Examples of the nonionic surfactant include acetylene glycol surfactants, polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene sorbitan fatty acid esters, polyoxypropylene polyoxyethylene alkyl ethers, polyoxyethylenes. Examples thereof include alkyl esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene alkyl amines, polyoxyethylene alkyl amides, and the like.

  Examples of the acetylene glycol surfactant include 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 3,6-dimethyl-4-octyne-3,6-diol, , 5-dimethyl-1-hexyn-3-ol and the like. Examples of commercially available acetylene glycol surfactants include Surfynol 104, 82, 465, 485, and TG manufactured by Air Products (USA).

  Examples of the amphoteric surfactant include lauryl aminopropionate, lauryl dimethyl betaine, stearyl dimethyl betaine, and lauryl dihydroxyethyl betaine. Specific examples include lauryl dimethylamine oxide, myristyl dimethylamine oxide, stearyl dimethylamine oxide, dihydroxyethyl lauryl amine oxide, polyoxyethylene coconut oil alkyl dimethyl amine oxide, dimethyl alkyl (coconut) betaine, dimethyl lauryl betaine, and the like. It is done.

  Among these surfactants, surfactants selected from the following general formulas (I), (II), (III), (IV), (V), and (VI) are preferable.

ただし、前記一般式（Ｉ）中、Ｒ^１は、アルキル基を表わす。ｈは、３〜１２の整数を表わす。Ｍは、アルカリ金属イオン、第４級アンモニウム、第４級ホスホニウム、及びアルカノールアミンから選択されるいずれかを表わす。

In the general formula (I), R ¹ represents an alkyl group. h represents an integer of 3 to 12. M represents one selected from alkali metal ions, quaternary ammonium, quaternary phosphonium, and alkanolamine.

ただし、前記一般式（ＩＩ）中、Ｒ^２は、アルキル基を表わす。Ｍは、アルカリ金属イオン、第４級アンモニウム、第４級ホスホニウム、及びアルカノールアミンから選択されるいずれかを表わす。

In the general formula (II), ^{R 2} represents an alkyl group. M represents one selected from alkali metal ions, quaternary ammonium, quaternary phosphonium, and alkanolamine.

ただし、前記一般式（ＩＩＩ）中、Ｒ^３は、炭化水素基を表わす。ｋは５〜２０の整数を表わす。

However, in the general formula (III), R ³ represents a hydrocarbon group. k represents an integer of 5 to 20.

ただし、前記一般式（ＩＶ）中、Ｒ^４は、炭化水素基を表わす。ｊは、５〜２０の整数を表わす。

In the general formula (IV), ^{R 4} represents a hydrocarbon group. j represents an integer of 5 to 20.

ただし、前記一般式（Ｖ）中、Ｒ^６は、炭化水素基を表わす。Ｌ及びｐは、１〜２０の整数を表わす。

In the general formula (V), R ⁶ represents a hydrocarbon group. L and p represent an integer of 1 to 20.

ただし、前記一般式（ＶＩ）中、ｑ及びｒは０〜４０の整数を表わす。

However, in said general formula (VI), q and r represent the integer of 0-40.

  Hereinafter, the surfactants of the structural formulas (I) and (II) are specifically shown in the free acid form.

前記フッ素系界面活性剤としては、例えば、パーフルオロアルキルスルホン酸化合物、パーフルオロアルキルカルボン化合物、パーフルオロアルキルリン酸エステル化合物、パーフルオロアルキルエチレンオキサイド付加物、及びパーフルオロアルキルエーテル基を側鎖に有するポリオキシアルキレンエーテルポリマー化合物、などが挙げられる。これらの中でも、パーフルオロアルキルエーテル基を側鎖に有するポリオキシアルキレンエーテルポリマー化合物は起泡性が少なく、近年問題視されているフッ素化合物の生体蓄積性についても低く安全性の高いものであり、特に好ましい。

Examples of the fluorosurfactant include a perfluoroalkyl sulfonic acid compound, a perfluoroalkyl carboxylic compound, a perfluoroalkyl phosphate compound, a perfluoroalkyl ethylene oxide adduct, and a perfluoroalkyl ether group in the side chain. And polyoxyalkylene ether polymer compounds. Among these, the polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain has a low foaming property, and the bioaccumulation property of a fluorine compound that has been regarded as a problem in recent years is low and highly safe. Particularly preferred.

  Examples of the perfluoroalkyl sulfonic acid compound include perfluoroalkyl sulfonic acid, perfluoroalkyl sulfonate, and the like. Examples of the perfluoroalkyl carboxylic compounds include perfluoroalkyl carboxylic acids and perfluoroalkyl carboxylic acid salts. Examples of the perfluoroalkyl phosphate compound include perfluoroalkyl phosphate esters, perfluoroalkyl phosphate salts, and the like. The polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain includes a polyoxyalkylene ether polymer having a perfluoroalkyl ether group in the side chain, and a polyoxyalkylene ether having a perfluoroalkyl ether group in the side chain. Examples thereof include a sulfate salt of a polymer and a salt of a polyoxyalkylene ether polymer having a perfluoroalkyl ether group in the side chain.

As counter ions of salts in these fluorosurfactants, Li, Na, K, NH ₄ , NH ₃ CH ₂ CH ₂ OH, NH ₂ (CH ₂ CH ₂ OH) ₂ , NH (CH ₂ CH ₂ OH) ₃ etc. are mentioned.

  As said fluorosurfactant, what was synthesize | combined suitably may be used and a commercial item may be used. As the fluorosurfactant, those represented by the following general formula (VII) are preferable.

ただし、前記一般式（ＶＩＩ）中、ｍは０〜１０の整数を表わす。ｎは１〜４０の整数を表わす。

However, in said general formula (VII), m represents the integer of 0-10. n represents an integer of 1 to 40.

  Examples of the commercially available products include Surflon S-111, S-112, S-113, S-121, S-131, S-132, S-141, and S-145 (all manufactured by Asahi Glass Co., Ltd.), Fullrad FC. -93, FC-95, FC-98, FC-129, FC-135, FC-170C, FC-430, FC-431 (all manufactured by Sumitomo 3M), MegaFuck F-470, F1405, F-474 (All manufactured by Dainippon Ink & Chemicals, Inc.), Zonyl TBS, FSP, FSA, FSN-100, FSN, FSO-100, FSO, FS-300, UR (all manufactured by DuPont), FT-110, FT- 250, FT-251, FT-400S, FT-150, FT-400SW (all manufactured by Neos Co., Ltd.), PF-151N (manufactured by Omninova), etc. I can get lost. Among these, Zonyl FS-300, FSN, FSN-100, and FSO (manufactured by DuPont) are particularly preferable from the viewpoints of reliability and color development improvement.

-Penetration agent-
The penetrant means an organic solvent that has a high effect of functionally promoting the penetration of ink into the paper (while the wetting agent is an organic solvent that has a wetting effect that prevents drying of the head). Specifically, polyol compounds and glycol ether compounds having 8 or more carbon atoms are applicable. That is, as the penetrant in the ink of this embodiment, a water-soluble organic solvent such as a polyol compound or a glycol ether compound is used. In particular, at least one of a polyol compound having 8 to 11 carbon atoms and a glycol ether compound is used. Preferably used.

  If the polyol compound has less than 8 carbon atoms, sufficient penetrability cannot be obtained, and the recording medium is soiled during double-sided printing, or ink spreading on the recording medium is insufficient, resulting in poor pixel filling. Therefore, character quality and image density may be reduced.

  Examples of the polyol compound having 8 or more carbon atoms include 2-ethyl-1,3-hexanediol (solubility: 4.2% (25 ° C.)), 2,2,4-trimethyl-1,3-pentanediol. (Solubility: 2.0% (25 ° C.)) is preferable.

  There is no restriction | limiting in particular in the addition amount of the said penetrant, Although it can select suitably according to the objective, 0.1-20 mass% is preferable, and 0.5-10 mass% is more preferable.

-Wetting agent-
The wetting agent is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include polyol compounds, nitrogen-containing heterocyclic compounds, amides, amines, sulfur-containing compounds, propylene carbonate, ethylene carbonate, At least one selected from urea compounds and saccharides is preferred.

  Examples of the polyol compound include polyhydric alcohols, polyhydric alcohol alkyl ethers, polyhydric alcohol aryl ethers, and the like. These may be used alone or in combination of two or more.

  Examples of the polyhydric alcohols include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4 butanediol, and 3-methyl-1. , 3-butanediol 1,3-propanediol, 1,5-pentanediol, 1,6 hexanediol, glycerol, 1,2,6-hexanetriol, 1,2,4-butanetriol, 1,2,3- Examples include butanetriol and petriol.

  Examples of the polyhydric alcohol alkyl ethers include ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, and propylene glycol monoethyl ether. It is done.

  Examples of the polyhydric alcohol aryl ethers include ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether.

  Examples of the nitrogen-containing heterocyclic compound include N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 2-pyrrolidone, 1,3-dimethylimidazolidinone, and ε-caprolactam. . Examples of the amides include formamide, N-methylformamide, formamide, N, N-dimethylformamide and the like. Examples of the amines include monoethanolamine, diethanolamine, triethanolamine, monoethylamine, diethylamine, and triethylamine. Examples of the sulfur-containing compounds include dimethyl sulfoxide, sulfolane, thiodiethanol, and the like. Examples of the urea compound include at least one selected from urea, thiourea, ethylene urea, and 1,3-dimethyl-2-imidazolidinone. In general, the amount of urea added to the ink is preferably 0.5 to 50% by mass, and more preferably 1 to 20% by mass.

Examples of the saccharide include monosaccharides, disaccharides, oligosaccharides (including trisaccharides and tetrasaccharides), polysaccharides, and derivatives thereof. Among these, glucose, mannose, fructose, ribose, xylose, arabinose, galactose, maltose, cellobiose, lactose, sucrose, trehalose, and maltotriose are preferable, and maltose, sorbitol, gluconolactone, and maltose are particularly preferable. The polysaccharide means a saccharide in a broad sense and can be used to include substances widely existing in nature such as α-cyclodextrin and cellulose. Examples of the saccharide derivatives include reducing sugars of the saccharides (for example, sugar alcohols (generally represented by HOCH ₂ (CHOH) _n CH ₂ OH (where n represents an integer of 2 to 5)), Examples include oxidized sugars (for example, aldonic acid, uronic acid, etc.), amino acids, thioic acids, etc. Among these, sugar alcohols are particularly preferable, and examples of the alcohol include maltitol, sorbit, and the like.

  Among these, glycerin, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1 from the viewpoint of obtaining excellent effects on solubility and prevention of poor jetting characteristics due to water evaporation , 3-butanediol, 2,3-butanediol, 1,4-butanediol, 3-methyl-1,3-butanediol 1,3-propanediol, 1,5-pentanediol, tetraethylene glycol, 1, 6-hexanediol, 2-methyl-2,4-pentanediol, polyethylene glycol, 1,2,4-butanetriol, 1,2,6-hexanetriol, thiodiglycol, 2-pyrrolidone, N-methyl-2 -Pyrrolidone, N-hydroxyethyl-2-pi Pyrrolidone is preferred.

  The content of the wetting agent in the ink is preferably 10 to 50% by mass, and more preferably 20 to 35% by mass. If the content is too small, the nozzle is likely to be dried and defective ejection of droplets may occur. If the content is too large, the ink viscosity is increased, and the proper viscosity range may be exceeded.

-Resin emulsion-
The ink of this embodiment can use any resin emulsion as a pigment fixing agent. The resin emulsion is obtained by dispersing resin fine particles in water as a continuous phase, and may contain a dispersant such as a surfactant as necessary. The content of resin fine particles as the dispersed phase component (content of resin fine particles in the resin emulsion) is generally preferably 10 to 70% by mass. Further, the particle diameter of the resin fine particles is preferably 10 to 1000 nm, more preferably 20 to 300 nm, particularly considering use in an ink jet recording apparatus.

  The resin fine particle component of the dispersed phase is not particularly limited and may be appropriately selected according to the purpose. For example, acrylic resin, vinyl acetate resin, styrene resin, butadiene resin, styrene-butadiene resin , Vinyl chloride resins, acrylic styrene resins, acrylic silicone resins, and the like. Among these, acrylic silicone resins are particularly preferable.

  As said resin emulsion, what was synthesize | combined suitably may be used and a commercial item may be used. Examples of the commercially available resin emulsion include Microgel E-1002, E-5002 (styrene-acrylic resin emulsion, manufactured by Nippon Paint Co., Ltd.), and Boncoat 4001 (acrylic resin emulsion, manufactured by Dainippon Ink & Chemicals, Inc.). ), Boncoat 5454 (styrene-acrylic resin emulsion, manufactured by Dainippon Ink & Chemicals, Inc.), SAE-1014 (styrene-acrylic resin emulsion, manufactured by Nippon Zeon Co., Ltd.), Cybinol SK-200 (acrylic resin emulsion, Seiden Chemical Co., Ltd.), Primal AC-22, AC-61 (acrylic resin emulsion, manufactured by Rohm and Haas), Nanoacryl SBCX-2821, 3689 (acrylic silicone resin emulsion, Toyo Ink Co., Ltd.) Company Ltd.), # 3070 (methyl methacrylate polymer resin emulsion, manufactured by Mikuni Color Ltd.).

  The addition amount of the resin fine particle component in the resin emulsion in the ink is preferably 0.1 to 50% by mass, more preferably 0.5 to 20% by mass, and still more preferably 1 to 10% by mass. If the addition amount is less than 0.1% by mass, the effect of improving clogging resistance and ejection stability may not be sufficient, and if it exceeds 50% by mass, the storage stability of the ink may be reduced. There is.

-Other ingredients-
The other components are not particularly limited and can be appropriately selected as necessary. For example, pH adjusters, antiseptic / antifungal agents, rust preventives, antioxidants, ultraviolet absorbers, oxygen absorbers, And light stabilizers.

  The pH adjuster is not particularly limited as long as it can adjust the pH to 7 or more without adversely affecting the ink to be prepared, and any substance can be used according to the purpose. Examples of the pH adjusting agent include amines such as diethanolamine and triethanolamine, hydroxides of alkali metal elements such as lithium hydroxide, sodium hydroxide and potassium hydroxide; ammonium hydroxide and quaternary ammonium hydroxide. Quaternary phosphonium hydroxide, alkali metal carbonates such as lithium carbonate, sodium carbonate, potassium carbonate, and the like.

-Ink manufacturing method-
The ink of this embodiment contains water, a particulate colorant, and a surfactant, and further, if necessary, a penetrating agent, a wetting agent, a resin emulsion, and other components are dispersed or dissolved in an aqueous medium, and further necessary. According to the above, the mixture is mixed by stirring. The dispersion can be performed by, for example, a sand mill, a homogenizer, a ball mill, a paint shaker, an ultrasonic disperser, etc., and stirring and mixing are performed by a stirrer using a normal stirring blade, a magnetic stirrer, a high-speed disperser, or the like. be able to.

-Solid content of ink-
The solid content of the ink of the present embodiment is desirably 6% by mass or more. If it is lower than this concentration, the viscosity increase during drying tends to be gradual and the image tends to blur. The higher the value, the better. However, if the value is too high, nozzle clogging becomes severe, and the image is liable to be lost. Therefore, the content is preferably 15% by mass or less.

-Ink physical properties-
It has been found that the ink of this embodiment preferably has very high permeability, and the condition is that the surface tension is preferably 30 mN / m or less. If the surface tension is greater than 30 mN / m, a phenomenon in which the ink permeates slowly and the image blurs occurs, so that a high-quality image cannot be obtained. The lower the surface tension, the better the separation between the pigment and the solvent. Therefore, a lower surface tension is desirable. However, when the surface tension is less than 15 mN / m, the nozzle plate is too wet to form ink droplets (particle formation). ) Cannot be performed well, or bleeding on the medium of the present embodiment becomes remarkable, and stable ink ejection may not be obtained. It is preferably 15 to 30 mN / m, and preferably 15 to 25 mN / m. More preferably. The surface tension of the ink can be adjusted by the amount of penetrating agent (for example, ethylhexanediol, also referred to as EHD) and the amount of fluorine-based surfactant (for example, FS300 manufactured by DuPont). Here, the said surface tension can be measured at 25 degreeC using a platinum plate, for example using a surface tension measuring apparatus (Kyowa Interface Science Co., Ltd. product, CBVP-Z).

  The ink of this embodiment can also be printed on a conventional void-type inkjet medium. However, in this case, since the ink absorption speed is too high, the solvent penetrates before the dots spread out after the ink droplets have landed on the medium surface, and the dot diameter becomes small. As a result, a decrease in density and an increase in graininess are likely to occur. Therefore, in order to create a high-quality image, it is necessary to increase the resolution for printing, which may cause a decrease in printing speed and an increase in ink consumption. Furthermore, when an image is formed on a highly absorptive medium such as an ink jet medium, the ink is rapidly absorbed by the medium after landing, so that the image surface of the ink recorded matter tends to be extremely protruding, Even if a gloss treatment solution is applied, it is difficult to achieve gloss.

  As physical properties of the ink, for example, the viscosity, pH, and the like are preferably in the following ranges. The viscosity of the ink is preferably 3 cps or more and 30 cps or less at 25 ° C., more preferably 5 to 20 cps. If the viscosity exceeds 20 cps, it may be difficult to ensure ejection stability. As said pH, 7-10 are preferable, for example.

<Clear ink>
In the recording method of the present embodiment, an image is formed using a high solid content ink on a medium having a very high background gloss, so that the image gloss tends to be lower than the background gloss. This is because, in part, the ink has a high pigment concentration and the ink has a fast drying property, so that it does not take enough time for the image surface to level. In some cases, the color material layer formed on the surface of the medium is thin, and it is difficult to form a smooth layer. In order to remedy these drawbacks, clear ink containing a resin component in the image area is printed in the post-processing step, and image gloss and image reliability are reduced by improving the image gloss and abrasion resistance. It can be realized at cost.

  The clear ink used in the post-processing step of the recording method of the present embodiment contains a resin emulsion in which resin fine particles are dispersed in water, and may contain other components as necessary.

-Resin emulsion-
The resin emulsion used in the clear ink of this embodiment is obtained by dispersing resin fine particles in water as a continuous phase, and may contain a dispersant such as a surfactant as necessary.

  The resin fine particle component of the dispersed phase in the resin emulsion is not particularly limited and may be appropriately selected depending on the intended purpose. For example, acrylic resin, vinyl acetate resin, styrene resin, butadiene resin, styrene- Examples thereof include butadiene resins, vinyl chloride resins, acrylic styrene resins, acrylic silicone resins, and among these, acrylic silicone resins are particularly preferable.

  In the clear ink of this embodiment, the finished image gloss can be adjusted by using a specific urethane emulsion in combination with the resin emulsion. By measuring the image gloss of clear ink using acrylic emulsion and the image gloss of clear ink using urethane emulsion on the desired media in advance, and proportionally allocating the usage rate according to the background gloss It is possible to balance the background gloss and the image gloss.

  As said resin emulsion, what was synthesize | combined suitably may be used and a commercial item may be used. As the commercially available resin emulsion, those similar to the commercially available resin emulsion used for the ink can be used.

  Content of the resin fine particles in the clear ink [content of resin fine particles in the clear ink. (Solid content)] is preferably 10% by mass or more and 60% by mass or less, and more preferably 10 to 30% by mass. When the addition amount is less than 10% by mass, the image cannot be glossy. When the addition amount exceeds 60% by mass, the ejection stability of the ink jet head is extremely deteriorated or the film forming property is deteriorated. The gloss may not be improved sufficiently. On the other hand, when the solid content exceeds 30% by mass, depending on the emulsion, the inkjet nozzle may be easily clogged, which may cause a problem in reliability. In general, the content of the resin fine particles in the resin emulsion is preferably 10 to 70% by mass. Further, the particle diameter of the resin fine particles is preferably 10 to 1000 nm, more preferably 20 to 300 nm from the viewpoint of ejection stability, particularly considering use in an ink jet recording apparatus.

-Other ingredients-
The resin emulsion constituting the clear ink of this embodiment forms a film when dried, and redispersibility and re-dissolvability are extremely reduced. Therefore, when it is dried in the vicinity of the head, ejection stability may be lowered. Therefore, the clear ink of this embodiment preferably contains a wetting agent. From the viewpoint of ejection stability, the amount of the wetting agent is preferably 20% by mass or more. However, if the amount is too large, dispersion breakage of the emulsion occurs and precipitation is likely to occur. Is desirable. As the type of wetting agent, the same wetting agent as that of the ink can be used.

  In addition, unlike the conventional clear ink, the clear ink of this embodiment may not be able to exhibit sufficient image gloss when the drying (penetration) speed is too fast. For this reason, the drying speed can be optimized by the mixing ratio of the solid content and the wetting agent amount. In this case, the drying rate can be adjusted quickly by increasing the ratio of water, decreasing the solid content, or increasing the amount of surfactant in the clear ink. As a result of the examination, it is desirable that the drying speed is 2 seconds or more and 60 seconds or less. If it is 2 seconds or less, the image gloss is not improved, and if it is 60 seconds or more, a problem is likely to occur in handling. The drying speed is determined by printing clear ink in a rectangular shape on the medium with the desired amount of adhesion, and pressing a paper that changes color with water, such as water cat paper, after a certain period of time has elapsed. Can do.

  In addition, various additives that can be used in the ink, such as preservatives and pH adjusters, can be used as they are in the clear ink.

-Physical properties of clear ink-
The viscosity of the clear ink is desirably 5 mPa · s or more and 30 mPa · s or less. If it is less than 5 mPa · s, the absorption speed of the clear ink is too fast, and sufficient time for the clear layer to level cannot be secured. The clear ink should have a high viscosity, but if it exceeds 30 mPa · s, it becomes difficult to eject from the inkjet nozzle. The viscosity can be adjusted by changing the component ratio of the wetting agent or changing the solid content ratio, and the same adjustment method as that of the ink described later can be used.

  The clear ink of this embodiment needs to have a low surface tension. In the present embodiment, in order to form an image on a medium with low ink absorption, the surface tension is controlled using a fluorosurfactant for the purpose of increasing the wettability of the colored ink as much as possible. As a result, the surface energy of the image formed is low due to the influence of the surfactant. The clear ink used in the conventional ink jet recording method causes repelling on the image, and uniform gloss cannot be obtained. Therefore, the surface tension needs to be 30 mN / m or less. The lower the value, the better. However, if it is less than 15 mN / m, the wettability with the ink jet nozzle is not balanced and it becomes difficult to form particles. Therefore, it is preferably 15 mN / m or more. For adjusting the surface tension, the method for adjusting the surface tension of the ink and the additives can be used as they are.

  In addition, when the clear ink of the present embodiment is used, depending on the type of emulsion to be used, the gloss of the medium may be excessively high. There is such a case in the combination of the strong glossy paper and the clear ink of the prior art. In such a case, the clear ink is often printed on the background portion to eliminate the gloss difference between the image and the background. Is called. However, in this case, the desired background gloss and texture are different, and there are many cases that cause problems.

<Media>
As an index of whether or not it is suitable as a medium of the present embodiment, first of all, it can be determined from the ink absorption amount of the dynamic scanning absorption meter. That is, it is desirable that the amount of ink absorbed into the medium at a contact time of 500 ms measured with a dynamic scanning absorption meter is 1 ml / m ² or more and 10 ml / m ² or less. Media that satisfy this condition can be regarded as having the function of the present invention, and by combining with the above ink, so-called "cut" is good, there is no blurring, feathering, or bleeding in the periphery of characters and images. A recorded image having a high optical density (OD) can be obtained. If the amount of absorption is less than 1 ml / m ² , the drying property is insufficient, and thus spur marks or beading is likely to occur, making it difficult to form a high-speed inkjet image. Also, if the absorption amount is greater than 10 ml / m ² , clear ink will be absorbed during post-processing, making uniform post-processing difficult and causing bleeding, and reducing the gloss of the image area after drying. . In addition, matching with various post treatments used in commercial printing such as lamination and foil stamping becomes difficult. In this embodiment, the contact time in the measurement of the ink absorption amount is set to 500 ms in order to express the permeability in a saturated state where the absorption of the ink into the medium is almost completed.

  Such a medium of this embodiment also includes a pigment and a resin binder in the coating layer, and has a configuration mainly composed of these, but the transfer amount is reduced by making the resin binder blending amount rich. The amount of absorption can be adjusted in the direction of increasing the pigment blending amount. It is also possible to increase the amount of absorption by increasing the specific surface area of the pigment particles constituting the coating layer, for example, by reducing the particle diameter or using a kind of pigment having a large specific surface area.

  Here, the dynamic scanning absorptiometer (DSA, Papa-Pagi Kyodo Journal, Vol. 48, May 1994, pp. 88-92) It is a device that can measure accurately. The dynamic scanning absorption meter reads the liquid absorption speed directly from the movement of the meniscus in the capillary, makes the sample a disk, and then scans the liquid absorption head in a spiral shape, and the scanning speed according to a preset pattern. Is automatically changed by a method in which the number of necessary points is measured with one sample. A liquid supply head for a paper sample is connected to a capillary via a Teflon (registered trademark) tube, and the position of the meniscus in the capillary is automatically read by an optical sensor. Specifically, the amount of transferred ink was measured using a dynamic scanning absorption meter (K350 series D type, manufactured by Kyowa Seiko Co., Ltd.). The transfer amount at the contact time of 500 ms can be obtained by interpolation from the measured value of the transfer amount at the contact time adjacent to each contact time. The measurement can be performed at 23 ° C. and 50% RH.

-Support-
Cellulose pulp is used as the media support of the present embodiment. More specifically, chemical pulp, mechanical pulp, waste paper recovered pulp and the like as the support are mixed at an arbitrary ratio and used as necessary, and an internal sizing agent, a yield improver, a paper strength enhancer, etc. The raw material added with a long net former or a gap type twin wire former, or a hybrid former in which the latter half of the long net part is composed of twin wires is used.

Pulp used for the media support of the present embodiment is virgin chemical pulp (CP), for example, hardwood bleached kraft pulp, softwood bleached kraft pulp, hardwood unbleached kraft pulp, softwood unbleached kraft pulp, hardwood bleached sulfite pulp Virgin chemical pulp made by chemically treating wood and other fiber raw materials such as softwood bleached sulfite pulp, hardwood unbleached sulfite pulp, softwood unbleached sulfite pulp, and virgin mechanical pulp (MP), For example, virgin mechanical pulp produced mainly by mechanically treating wood such as ground pulp, chemi-ground pulp, chemi-mechanical pulp, semi-chemical pulp, and other fiber raw materials may be included.

  Waste paper pulp may also be used. As the raw material for waste paper pulp, the white paper, ruled white, cream white card, white, medium white, Imitation, fair-skinned, Kent, white art, special top-off, separate top-off, newspaper, magazine, etc. Specifically, printer paper such as non-coating computer paper, thermal paper, and pressure-sensitive paper as information-related paper; OA waste paper such as PPC paper; coating of art paper, coated paper, finely coated paper, matte paper, etc. Paper: High quality paper, color quality, notebook, notepaper, wrapping paper, fancy paper, medium quality paper, newsprint, reprint paper, super paper, imitation paper, pure white roll paper, uncoated paper such as milk carton, etc. Examples of used paper and paperboard include chemical pulp paper and high-yield pulp-containing paper. These may be used individually by 1 type and may use 2 or more types together.

The waste paper pulp is generally produced from a combination of the following four steps.
(1) For disaggregation, waste paper is treated with mechanical force and chemicals with a pulper to loosen it into a fibrous form, and the printing ink is peeled off from the fiber.
(2) Dust removal is to remove foreign matter (plastic etc.) and dust contained in waste paper with a screen, cleaner or the like.
(3) In the deinking, the printing ink peeled off from the fiber using a surfactant is removed from the system by a flotation method or a cleaning method.
(4) Bleaching increases the whiteness of the fiber using an oxidizing action or a reducing action.

  When mixing the used paper pulp, the mixing ratio of the used paper pulp in the total pulp is preferably 40% or less from the viewpoint of curling after recording.

  As a filler that can be used for the media support of the present embodiment, calcium carbonate is effective, but inorganic fillers such as kaolin, calcined clay, pyrophyllite, sericite, talc and the like, and satin white Organic pigments such as barium sulfate, calcium sulfate, zinc sulfide, plastic pigment, urea resin can be used in combination.

  The internal sizing agent used for the support in the medium of the present embodiment is not particularly limited, and is appropriately selected from known internal sizing agents used for inkjet recording paper and commercial printing paper. be able to. For example, rosin emulsion sizing agents and the like can be mentioned. Neutral rosin sizing agents used for neutral papermaking, alkenyl succinic anhydride (ASA), alkyl ketene dimers (AKD) to increase the paper surface pH. Petroleum resin-based sizing agents are desirable. Among these, a neutral rosin sizing agent or alkenyl succinic anhydride is particularly preferable. The amount of the internally added sizing agent is preferably 0.1 to 0.7 parts by mass with respect to 100 parts by mass of the absolutely dry pulp, but is not limited thereto.

  As the internal filler used for the support, for example, a conventionally known pigment is used as a white pigment. Examples of the white pigment include light calcium carbonate, heavy calcium carbonate, kaolin, clay, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc sulfide, zinc carbonate, satin white, aluminum silicate, diatomaceous earth, White inorganic pigments such as calcium silicate, magnesium silicate, synthetic silica, aluminum hydroxide, alumina, lithopone, zeolite, magnesium carbonate, magnesium hydroxide; styrene plastic pigment, acrylic plastic pigment, polyethylene, microcapsule, urea resin And organic pigments such as melamine resin. These may be used individually by 1 type and may use 2 or more types together.

-Coating layer-
The media coating layer of this embodiment contains a pigment and a resin binder (binder), and further contains a surfactant and other components as necessary. As the pigment, an inorganic pigment or a combination of an inorganic pigment and an organic pigment can be used.

  Examples of the inorganic pigment include kaolin, talc, heavy calcium carbonate, light calcium carbonate, calcium sulfite, amorphous silica, titanium white, magnesium carbonate, titanium dioxide, aluminum hydroxide, calcium hydroxide, magnesium hydroxide, Zinc hydroxide, clawlite, illite, clay and the like can be mentioned. Among these pigments, the thickness of the coating layer can be reduced by using a pigment having a refractive index as high as possible. However, it is preferable to use calcium carbonate or kaolin from the viewpoint of cost, and kaolin is particularly preferable because kaolin is excellent in glossiness and can be made close to a paper for offset printing. These pigments can be used in combination as long as the effects of the present invention are not impaired, and can also be used in combination with other pigments not listed.

  The kaolin includes delaminated kaolin, calcined kaolin, engineered kaolin by surface modification, etc. In consideration of gloss expression, the particle size distribution is such that the ratio of the particle size is 2 μm or less is 80% by mass or more. It is preferable that the kaolin which has occupies 50 mass% or more of the whole kaolin. The amount of kaolin added is preferably 50 parts by mass or more with respect to 100 parts by mass of the total pigment in the coating layer. When the addition amount is less than 50 parts by mass, a sufficient effect on glossiness may not be obtained. The upper limit of the addition amount is not particularly limited, but is preferably 90 parts by mass or less from the viewpoint of coating suitability in consideration of the fluidity of kaolin, particularly the thickening under high shear force.

  Further, these high refractive index pigments and low refractive index silica or organic pigments may be used in combination. Examples of the organic pigment include water-soluble dispersions such as styrene-acrylic copolymer particles, styrene-butadiene copolymer particles, polystyrene particles, and polyethylene particles. Two or more of these organic pigments may be mixed. The addition amount of the organic pigment is preferably 2 to 20 parts by mass with respect to 100 parts by mass of the total pigment in the coating layer. Since the organic pigment is excellent in gloss expression and its specific gravity is smaller than that of an inorganic pigment, it is possible to obtain a coating layer that is bulky, high gloss, and has good surface coverage. If the addition amount is less than 2 parts by mass, the above effect is not obtained. If the addition amount exceeds 20 parts by mass, the fluidity of the coating liquid is deteriorated, leading to a decrease in coating operability, and economical in terms of cost. Not right. The organic pigment includes a solid type, a hollow type, a donut type, and the like in terms of its form, but the average particle size is 0.2 in view of the balance of gloss development, surface coverage, and fluidity of the coating liquid. A hollow mold having a porosity of 40% or more is more preferable.

  The resin binder of the colorant pigment coating layer used in the medium of the present embodiment has a strong adhesive force with the pigment and the base paper constituting the coating layer, and is an aqueous resin or emulsion that does not cause blocking. It is not particularly limited.

Such aqueous binders include, for example, starches such as polyvinyl alcohol, oxidized starch, esterified starch, enzyme-modified starch, and cationized starch, and fiber derivatives such as casein, soy protein, carboxymethylcellulose, and hydroxyethylcellulose. Styrene-acrylic resin, isobutylene-maleic anhydride resin, acrylic emulsion, vinyl acetate emulsion, vinylidene chloride emulsion, polyester emulsion, SBR (Styrene Butadiene Rubber) latax, acrylonitrile butadiene latex and the like. Among these, it is preferable to use starch or styrene-butadiene latex from the viewpoint of cost. Here, the SBR latex is a synthetic rubber latex having a styrene-butadiene copolymer as a discontinuous phase, which is produced by an emulsion polymerization method with styrene and butadiene monomers as main components and adding other monomers as necessary. is there. This SBR latex is a resin binder generally used for paper coating in cast coated paper, and when added to the coating layer, the surface of the media becomes hydrophobic and the wettability of the inkjet ink deteriorates. Since it is not compatible with a cationic agent used as a fixing agent for inkjet ink, it is not usually used for inkjet paper, but it is extremely preferable for improving offset printing suitability. As the other monomer, vinyl monomers such as acrylic acid, methacrylic acid, acrylic acid or alkyl esters of methacrylic acid, acrylonitrile, maleic acid, fumaric acid, vinyl acetate are often used. Further, it may contain a crosslinking agent such as methylolated melamine, methylolated urea, methylolated hydroxypropylene urea, isocyanate, etc., or a copolymer containing units such as N-methylolacrylamide and having a self-crosslinking property. Also good. These may be used individually by 1 type and may use 2 or more types together. The styrene monomer content in the styrene-butadiene copolymer constituting the SBR latex is preferably 20 to 80% by mass, and the butadiene monomer content is preferably 80 to 20% by mass.
The use ratio of the added amount of the resin binder in the coating layer used in the medium of the present embodiment is preferably 50 to 70% by mass, more preferably 55 to 60% by mass of the total coating layer solid content. If the amount is too small, the adhesive strength becomes insufficient, and there is a concern that the strength of the ink receiving layer is lowered, the internal bond strength is lowered, and the occurrence of powder falling.

  Other components can be added to the coating layer of the media of the present embodiment as necessary, as long as the object and effect of the present invention are not impaired. In addition to various auxiliary agents blended in ordinary coated paper pigments, such as dispersants, thickeners, water retention agents, antifoaming agents, water-proofing agents, etc. as other components, pH adjusters, preservatives, oxidation agents Additives such as inhibitors and cationic organic compounds may be used.

  The surfactant used in the coating layer is not particularly limited and may be appropriately selected depending on the purpose. Examples of the surfactant include anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants. Any of them can be used, and among these, a nonionic surfactant is particularly preferable. By adding the surfactant, the water resistance of the image is improved, the image density is increased, and bleeding is improved.

  Examples of the nonionic surfactant include higher alcohol ethylene oxide adducts, alkylphenol ethylene oxide adducts, fatty acid ethylene oxide adducts, polyhydric alcohol fatty acid ester ethylene oxide adducts, higher aliphatic amine ethylene oxide adducts, and fatty acids. Amide ethylene oxide adduct, fat ethylene oxide adduct, polypropylene glycol ethylene oxide adduct, fatty acid ester of glycerol, fatty acid ester of pentaerythritol, fatty acid ester of sorbitol and sorbitan, fatty acid ester of sucrose, alkyl ether of polyhydric alcohol And fatty acid amides of alkanolamines. These may be used individually by 1 type and may use 2 or more types together.

  There is no restriction | limiting in particular as said polyhydric alcohol, According to the objective, it can select suitably, For example, glycerol, a trimethylol propane, a pentaerythritol, sorbitol, sucrose etc. are mentioned. As the ethylene oxide adduct, those obtained by substituting a part of ethylene oxide with an alkylene oxide such as propylene oxide or butylene oxide are also effective as long as water solubility can be maintained. The substitution rate is preferably 50% or less. 4-15 are preferable and, as for HLB (hydrophilic new oil ratio) of the said nonionic surfactant, 7-13 are more preferable. The addition amount of the surfactant is preferably 0 to 10 parts by mass, and more preferably 0.1 to 1.0 part by mass with respect to 100 parts by mass of the cationic organic compound.

  Other components can be further added to the coating layer as necessary, as long as the objects and effects of the present invention are not impaired. Examples of the other components include additives such as alumina powder, pH adjuster, preservative, and antioxidant.

  Further, in the case of the media of this embodiment, the cationic organic compound does not necessarily need to be blended, and conversely, if it is added too much, the paper surface pH is often lowered, but it is selectively used depending on the purpose. be able to.

  Examples of the cationic organic compound include dimethylamine / epichlorohydrin polycondensate, dimethylamine / ammonia / epichlorohydrin condensate, poly (trimethylaminoethyl methacrylate / methyl sulfate), diallylamine hydrochloride / acrylamide copolymer, (Diallylamine hydrochloride / sulfur dioxide), polyallylamine hydrochloride, poly (allylamine hydrochloride / diallylamine hydrochloride), acrylamide / diallylamine copolymer, polyvinylamine copolymer, dicyandiamide, dicyandiamide / ammonium chloride / urea / formaldehyde condensate , Polyalkylene polyamine dicyandiamide ammonium salt condensate, dimethyl diallyl ammonium chloride, polydiallyl methylamine hydrochloride, poly (diallyldi Tylammonium chloride), poly (diallyldimethylammonium chloride / sulfur dioxide), poly (diallyldimethylammonium chloride / diallylamine hydrochloride derivative), acrylamide / diallyldimethylammonium chloride copolymer, acrylate / acrylamide / diallylamine Examples thereof include hydrochloride copolymer, polyethyleneimine, ethyleneimine derivatives such as acrylicamine polymer, and polyethyleneimine alkylene oxide modified products. These may be used individually by 1 type and may use 2 or more types together.

  Although it does not prescribe | regulate especially as a method of providing a coating layer by the application | coating to the support body of the medium of this embodiment, the method of apply | coating directly, the method of transferring what was once applied on the other base material to a medium, spray etc. Spraying methods can be used. Examples of the direct coating method include a roll coater method, an air knife coater method, a gate roll coater method, a size press method, a shim sizer method, a rod metering size press coater, etc., a film transfer method, a blade coater method by a fountain or roll application, etc. Can be mentioned. A casting method can also be used to produce a highly glossy surface.

  Among these, from the viewpoint of cost, a method of impregnating or adhering with a conventional size press, a gate roll size press, a film transfer size press or the like installed in a paper machine and finishing on-machine is preferable.

There is no restriction | limiting in particular in the adhesion amount of the said coating layer liquid, Although it can select suitably according to the objective, 0.5-25 g / m < ² > is preferable at solid content. If it is less than 0.5 g / m ² , the ink color material component cannot be sufficiently separated, so that the color material penetrates into the paper, resulting in a decrease in density and character bleeding. After the impregnation or coating, drying may be performed as necessary. In this case, the drying temperature is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably about 100 to 250 ° C. .

  The coating layer can be dried using, for example, a hot air drying furnace, a hot drum, or the like. Furthermore, in order to smooth the surface or increase the strength of the surface, surface finishing may be performed with a calendar device (super calendar, soft calendar, gloss calendar, etc.).

The basis weight of the media according to the present embodiment is preferably 100 to 300 g / m ² . If it is less than 100 g / m ² , there is no stiffness and the quality is inferior. If it exceeds 300 g / m ² , the stiffness becomes too large, so that the recording medium cannot be bent at the curved portion in the middle of the conveying path, and a conveyance defect such as clogging of the recording medium is likely to occur.

  Unlike the conventional ink-jet media, the media of this embodiment has a lower ink absorbability, and the final gloss treatment is easier to perform uniformly. In other words, if the ink absorptivity is high, clear ink or the like is absorbed, making uniform film formation difficult and making it difficult to obtain gloss. It is sufficient to increase the amount of clear ink attached, but problems such as increased costs, distortion of the paper, and uneven gloss due to uneven drying occur.

As such a medium having low ink absorptivity and in which an ink component hardly penetrates into paper, cast coated paper is preferably used. The cast-coated paper is classified according to the production method, unlike the above-mentioned classification based on the coating amount. Generally, the coating liquid is wound around a heated mirror roll (cast drum) in a state of being dried. By transferring, smoothness like a mirror surface is imparted to the paper surface. The coating amount of cast coated paper is usually about ²⁰ to 30 g / m ^{2 in} terms of solid amount. Specific products of cast coated paper include Mirror Coat Platinum (Oji Paper), Esprit Coat C (Nippon Paper Industries), and the like.

According to the present embodiment, even if other coated paper for printing is used, a satisfactory image can be formed as long as the ink absorption amount condition is satisfied. As such coated paper for printing, so-called art paper (A0, A1) and coated paper (A2, B2), which are conventionally classified according to the coating amount according to the classification of varieties of the Ministry of Economy, Trade and Industry and the Japan Paper Association. These are coated papers used for commercial printing and publishing printing such as lightweight coated paper (A3, B3) and fine coated paper, and are used for offset printing, gravure printing, and the like. Here, the art paper are those coating weight of the single-sided 20 g / ^{m 2} or more in terms of solid content, a single-sided ^10g / ^{m 2 ~20g} / m 2 in solid weight coating amount as coated paper, lightweight the coated paper, coating weight is one-sided 6g / m ² ~10g / m ² approximately by solid weight, the finely coated paper is intended coating amount of the single-sided 6 g / m ² or less in terms of solid weight .

  Art paper includes OK Kanfuji N, OK Kanfuji-R40N, SA Kanfuji N, Satin Kanfuji N, Satin Kanfuji-R40N, Ultra Satin Kanfuji N, Ultra OK Kanfuji N, Kanto One Side (Oji Paper), NPi Special Art, NPi Super Art, NPi Super Dal, NPi Dal Art (Nippon Paper), Utrillo Super Art, Utrillo Super Dal, Utrillo Premium (Daiou Paper), Fine Art A, Tohishi Art, Super Matte Art A, Luxury Dal Art A (Mitsubishi Paper), Thunderbird Examples include Super Art N, Thunderbird Super Art MN, Thunderbird Special Art, Thunderbird Dull Art N (Chuetsu Pulp).

  As A2 coated paper, OK top coat + (plus), OK top coat S, OK Casablanca, OK Casablanca V, OK Trinity, OK Trinity NaVi, New Age, New Age W, OK Top Coat Mat N, OK Royal Coat, OK Top Coat Dull, Z Coat, OK Bulk Princess, OK Bulk King, OK Bulk King Satin, OK Top Coat +, OK Non Wrinkle, OK Court V, OK Court N Green 100, OK Matt Court Green 100, New Age Green 100 , Z Coat Green 100 (Oji Paper), Aurora Coat, Shiraoi Mat, Imperial Mat, Silver Diamond, Recycle Coat 100, Cycle Mat 100 (Nippon Paper Industries), Mu Coat, Mu White, Mu Mat, White Mu Mat (North) Papermaking), Thunderbird coat N, Regina thunderbird coat 100, Thunderbird mat coat N, Regina thunderbird mat 100 (Chuetsu Pulp Industry), Pearl coat, White pearl coat N, New V mat, White new V mat, Pearl coat REW, White pearl Examples thereof include coat NREW, new V mat REW, white new V mat REW (Mitsubishi Paper), and the like.

  As A3 coated (lightweight coated) paper, OK Coat L, Royal Coat L, OK Coat LR, OK White L, OK Royal Coat LR, OK Coat L Green 100, OK Matt Coat L Green 100 (Oji Paper), Easter DX , Recycle Coat L100, Aurora L, Recycle Mat L100, <SSS> Energy White (Nippon Paper), Utrillo Coat L, Mathis Coat (Dao Paper), High Alpha, Alpha Matt, (N) Kinmari L, Kinmari HiL (Hokuetsu) Papermaking), N pearl coat L, N pearl coat LREW, swing mat REW (Mitsubishi Paper), Super Emine, Emine, Chaton (Chuetsu Pulp Industries), and the like.

  Examples of the B2 coat (medium coat) paper include OK medium coat, (F) MCOP, OK Astro Ross, OK Astro Dal, OK Astro Mat (Oji Paper), King O (Nippon Paper Industries), and the like.

  Finely coated paper includes OK Royal Light S Green 100, OK Everlight Coat, OK Everlight R, OK Evergreen, Clean Hit MG, OK Fine Coating Super Eco G, Eco Green Dal, OK Fine Coating Matte Eco G100, OK Starlight Coat, OK Soft Royal, OK Bright, Clean Hit G, Yamayuri Bright, Yamayuri Bright G, OK Aqua Light Coat, OK Royal Light S Green 100, OK Bright (Rough / Shiny), Snow Mat, Snow Mat DX, OK Bulk Princess, OK Bulk Lily (Oji Paper), Pyrenees DX, Pegasus Hyper 8, Aurora S, Andes DX, Super Andes DX, Space DX, Seine DX, Special Gravure DX, Pegasus, Silver Pegasus, Pegasus Harmony, Greenland X100, Super Greenland DX100, <SSS> Energy Soft, <SSS> Energy Light, EE Henry (Nippon Paper Industries), Canto Excel, Excel Super B, Excel Super C, Canto Excel Bar, Utrillo Excel, Heine Excel, Dante Excel ( Daio Paper), Cosmo Ace (Daiso Showa Paperboard), Semi Upper L, High Beta, High Gamma, Shiromari L, Hamming, White Hamming, Semi Upper HiL, Shiromari HiL (Hokuetsu Paper), Ruby Light HREW, Pearl Soft, Ruby Light H (Mitsubishi Paper), Chaton, Aliso, Smash (Chuetsu Pulp Industries), Star Cherry, Cherry Super (Maruzumi Paper) and the like.

  In addition, as a special coated paper, if it already satisfies the conditions of this patent, it can be used as a medium of this patent. For example, some coated paper for electrophotography and coated paper for gravure printing can be mentioned. Specific examples include POD gloss coat (Oji Paper), Space DX (Nippon Paper Industries), and Ace (Nippon Paper Industries). These have an appropriate pore volume of the coating layer and can be used as the media of this patent.

-Media properties-
The 60 ° glossiness defined in JIS-ZS-8741 of the media is 50% or more, preferably 70% or more. When the 60 ° glossiness is less than 50%, the glossiness of the recorded matter is insufficient, which is not preferable.

<Recording method>
The recording method of the present embodiment includes at least an image forming step of flying the ink on the medium to form an image and a post-processing step of applying the clear ink to the medium on which the image has been formed by the image forming step. The recording method of the present embodiment can be preferably implemented by a recording apparatus described later. The size of the droplets of ink to be ejected is preferably 1 to 40 pl, the speed of ejection and ejection is preferably 5 to 20 m / s, and the driving frequency is 1 kHz or more. The resolution is preferably 300 dpi or more.

  In the recording method of the present embodiment, the total amount of ink (also referred to as the amount of adhesion) is used to prevent the color material from penetrating into the ink and efficiently distribute it near the surface of the medium, and at the same time to ensure the drying property of the ink. Need to be restricted. The total amount of ink is an important parameter when forming an image, and indicates the amount of ink per unit area when forming a solid image with the highest density. In the present invention, by defining the total amount of ink, it is possible to form a uniform image with less beading and bleeding even on media having poor ink absorbability. Conversely, exceeding this upper limit, if a large amount of ink is used as in the conventional ink jet recording method, the ink colorant pigment penetrates together with the ink solvent, or the penetration of the solvent component of the ink is not in time, Since the image formation is greatly hindered, a high quality image cannot be obtained.

Specifically, when the ink of the present embodiment is used, the maximum ink adhesion amount (ink total amount regulation value) at the time of image creation may be 15 g / m ² , and by performing image formation with an ink adhesion amount less than that, A very high quality image without beading or bleeding can be obtained. It was also found that it is desirably 12 g / m ² or less.

  This is different from the conventional combination of dye ink and ink-jet media. In the case of the pigment ink and media of this embodiment, the color material is present in the form of being deposited on the surface of the media and is necessary to cover the surface of the media. If there is a sufficient amount of color material, not only the color material beyond that is wasted, but even with the highly penetrating ink of this embodiment, the excess ink solvent interferes with adjacent dots, leading to beading and bleeding. This is because it will generate.

  In particular, even if the ink of this embodiment is used, if the total amount restriction value of the ink is set high as in the case of the conventional ink jet recording, a large amount of ink is used in the solid portion and the shadow portion, and the color material of the medium The separation ability is exceeded, the image is blurred, and the drying property is greatly reduced.

  Furthermore, by reducing the total amount of ink required for printing, the capacity of the ink cartridge can be reduced compared to the conventional ink jet printer, and the apparatus can be made compact. Further, if the cartridge size is the same as the conventional one, the replacement frequency of the ink cartridge can be reduced, and printing at a lower cost is possible.

  Basically, the smaller the total amount of ink, the more effective the pigment separation ability of the media coating layer is. However, if the amount is too small, there is a side effect that the image dot diameter after printing becomes too small. It is desirable to set (regulate) the total amount of ink within this range according to the image.

  In the present embodiment, the total amount of ink was measured using a mass method. Specifically, a 5cm x 20cm rectangular solid image is printed at the highest density on Superfine exclusive paper (manufactured by Epson), which is dedicated for inkjet printing, and the mass is measured immediately after printing, and the mass before printing is subtracted. Was multiplied by 100 to obtain the total amount of ink.

A conventional ink jet method can be used as it is as a clear ink application method in the post-processing step in the recording method of the present embodiment. Depending on the purpose, as a clear ink application method in the post-processing step, a method of applying clear ink using a bar coater, an offset printer, a screen printer, a roll coater, or the like may be used. The adhesion amount of the clear ink in the post-treatment step is 0.3 g / m ² or more and 5 g / m ² or less, preferably 1.0 g / m ² or more and 4 g / m ² or less in terms of dry weight. If it is less than 0.3 g / m ² , the image gloss may not be improved. If it is more than 5 g / m ^2, gloss unevenness due to poor drying or uneven absorption may occur, which is not preferable.

<Ink cartridge>
The ink cartridge of the present embodiment contains the ink of the present invention in a container, and further includes other members and the like appropriately selected as necessary. The container is not particularly limited, and its shape, structure, size, material and the like can be appropriately selected according to the purpose. For example, at least an ink bag formed of an aluminum laminate film, a resin film, or the like Preferred examples include those possessed.

  Next, the ink cartridge will be described with reference to FIGS. Here, FIG. 1 is a view showing an example of the ink cartridge of the present embodiment, and FIG. 2 is a view including a case (exterior) of the ink cartridge of FIG.

  As shown in FIG. 1, the ink cartridge (200) is filled into the ink bag (241) from the ink inlet (242) and exhausted, and then the ink inlet (242) is closed by fusion. In use, the needle of the apparatus main body is pierced into the ink discharge port (243) made of a rubber member and supplied to the apparatus.

<Inkjet recording apparatus>
The ink jet recording apparatus of this embodiment includes at least ink flying means, and further includes other means appropriately selected as necessary, for example, stimulus generation means, control means, and the like.

-Ink flying means-
The ink flying means is means for applying a stimulus to the ink of the present embodiment and causing the ink to fly to record an image on the medium of the present embodiment. The ink flying means is not particularly limited, and examples thereof include various nozzles for ejecting ink.

In the present embodiment, it is preferable that at least a part of the liquid chamber portion, the fluid resistance portion, the vibration plate, and the nozzle member of the ink jet head are formed of a material containing at least one of silicon and nickel. The nozzle diameter of the inkjet nozzle is preferably 30 μm or less, and preferably 1 to 20 μm.

  The stimulus can be generated by, for example, the stimulus generating means, and the stimulus is not particularly limited and can be appropriately selected according to the purpose, and includes heat, pressure, vibration, light, and the like. . These may be used individually by 1 type and may use 2 or more types together. Among these, heat and pressure are preferable.

  The mode of ink flying in the ink jet recording method is not particularly limited, and varies depending on the type of the stimulus. For example, when the stimulus is “heat”, a recording signal is output to the ink in the recording head. A method of applying corresponding thermal energy using, for example, a thermal head, generating bubbles in the ink by the thermal energy, and discharging and ejecting the ink as droplets from the nozzle holes of the recording head by the pressure of the bubbles , Etc. When the stimulus is “pressure”, for example, by applying a voltage to a piezoelectric element bonded to a position called a pressure chamber in an ink flow path in the recording head, the piezoelectric element is bent, and the volume of the pressure chamber is reduced. And a method of reducing and ejecting the ink as droplets from the nozzle holes of the recording head.

  One aspect of carrying out the ink jet recording method of the present embodiment by the ink jet recording apparatus of the present embodiment will be described with reference to the drawings. The ink jet recording apparatus shown in FIG. 3 has an apparatus main body (101), a paper feed tray (102) for loading paper mounted on the apparatus main body (101), and an image mounted on the apparatus main body (101). A paper discharge tray (103) for stocking the formed paper and an ink cartridge loading section (104) for loading the ink cartridge are provided. On the upper surface of the ink cartridge loading section (104), an operation section (105) such as operation keys and a display is arranged. The ink cartridge loading section (104) has an openable / closable front cover (115) for attaching and detaching the ink cartridge (200).

  As shown in FIGS. 4 and 5, a guide rod (131), which is a guide member horizontally mounted on left and right side plates (not shown), and a stay (132) are provided in the apparatus main body (101). 133) is slidably held in the main scanning direction, and is moved and scanned in the direction of the arrow in FIG. 5 by a main scanning motor (not shown).

  Hereinafter, an inkjet head to which the present embodiment is applied will be described. FIG. 6 is an enlarged view of elements of an ink jet head according to an embodiment of the present invention, and FIG. 7 is an enlarged cross-sectional view of the main part in the direction between channels of the head.

  This ink-jet head includes a frame (10) formed with an engraving serving as an ink supply port (not shown) and a common liquid chamber (1b), an engraving and a nozzle serving as a fluid resistance portion (2a) and a pressurized liquid chamber (2b). A flow path plate (20) having a communication port (2c) communicating with (3a), a nozzle plate forming a nozzle (3a), a convex portion (6a), a diaphragm portion (6b), and an ink inflow port (6c). ), A laminated piezoelectric element (50) bonded to the diaphragm (60) via an adhesive layer (70), and a base (50) to which the laminated piezoelectric element (50) is fixed. 40).

  The base (40) is made of a barium titanate ceramic, and the laminated piezoelectric elements (50) are arranged in two rows and joined.

<Ink record>
The ink recorded matter recorded by the inkjet recording method of this embodiment is the ink recorded matter of this embodiment. The ink recorded matter of this embodiment has high image quality, no bleeding, excellent stability over time, and can be suitably used for various purposes as a material on which various prints or images are recorded.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

-Ink adjustment-
Production Example 1: Cyan dispersion (copper phthalocyanine pigment-containing polymer fine particle dispersion)
After sufficiently replacing the inside of the 1 L flask equipped with a mechanical stirrer, thermometer, nitrogen gas introduction tube, reflux tube, and dropping funnel with nitrogen gas, 11.2 g of styrene, 2.8 g of acrylic acid, 12.0 g of lauryl methacrylate Then, 4.0 g of polyethylene glycol methacrylate, 4.0 g of styrene macromer (manufactured by Toa Gosei Co., Ltd., trade name: AS-6) and 0.4 g of mercaptoethanol were charged and heated to 65 ° C. Next, 100.8 g of styrene, 25.2 g of acrylic acid, 108.0 g of lauryl methacrylate, 36.0 g of polyethylene glycol methacrylate, 60.0 g of hydroxyethyl methacrylate, styrene macromer (trade name: AS-6, manufactured by Toagosei Co., Ltd.) A mixed solution of 36.0 g, mercaptoethanol 3.6 g, azobisdimethylvaleronitrile 2.4 g, and methyl ethyl ketone 18 g was dropped into the flask over 2.5 hours.

  After completion of dropping, a mixed solution of 0.8 g of azobisdimethylvaleronitrile and 18 g of methyl ethyl ketone was dropped into the flask over 0.5 hours. After aging at 65 ° C. for 1 hour, 0.8 g of azobisdimethylvaleronitrile was added, and further aging was performed for 1 hour. After completion of the reaction, 364 g of methyl ethyl ketone was added to the flask to obtain 800 g of a polymer solution having a concentration of 50% by mass. Next, when a part of the polymer solution was dried and measured by gel permeation chromatography (standard: polystyrene, solvent: tetrahydrofuran), the weight average molecular weight (Mw) was 15000.

  Next, 28 g of the obtained polymer solution, 26 g of copper phthalocyanine pigment, 13.6 g of 1 mol / L potassium hydroxide aqueous solution, 20 g of methyl ethyl ketone, and 30 g of ion-exchanged water were sufficiently stirred. Thereafter, the mixture was kneaded 20 times using a three-roll mill (manufactured by Noritake Company, trade name: NR-84A). The obtained paste was put into 200 g of ion-exchanged water and sufficiently stirred, and then methyl ethyl ketone and water were distilled off using an evaporator to obtain 160 g of a blue polymer fine particle dispersion having a solid content of 20.0% by mass. . About the obtained polymer microparticles | fine-particles, the average particle diameter (D50%) measured with the particle size distribution analyzer (Microtrac UPA, Nikkiso Co., Ltd.) was 93 nm.

Production Example 2: Magenta dispersion (dimethylquinacridone pigment-containing polymer fine particle dispersion)
A red-purple polymer fine particle dispersion was prepared in the same manner as in Production Example 1 except that the copper phthalocyanine pigment was changed to Pigment Pigment Red 122 in Production Example 1. About the obtained polymer microparticles | fine-particles, the average particle diameter (D50%) measured with the particle size distribution analyzer (Microtrac UPA, Nikkiso Co., Ltd.) was 127 nm.

Production Example 3: Yellow dispersion (monoazo yellow pigment-containing polymer fine particle dispersion)
A yellow polymer fine particle dispersion was prepared in the same manner as in Production Example 1 except that the copper phthalocyanine pigment was changed to Pigment Pigment Yellow 74 in Production Example 1. About the obtained polymer microparticles | fine-particles, the average particle diameter (D50%) measured with the particle size distribution analyzer (Microtrac UPA, Nikkiso Co., Ltd.) was 76 nm.

Production Example 4: Black dispersion (carbon black polymer fine particle dispersion)
A black polymer fine particle dispersion was prepared in the same manner as in Production Example 1 except that the copper phthalocyanine pigment was changed to carbon black (Degussa, FW100) in Production Example 1. About the obtained polymer microparticles | fine-particles, the average particle diameter (D50%) measured with the particle size distribution analyzer (Microtrac UPA, Nikkiso Co., Ltd.) was 104 nm.

  Next, an ink composition was produced using the polymer fine particle dispersion obtained in Production Examples 1 to 4 above.

Production Example 5: Cyan ink 1
Copper phthalocyanine pigment-containing polymer fine particle dispersion 20.0% by mass of production example 1, 3-methyl-1,3-butanediol 23.0% by mass, glycerin 8.0% by mass, 2-ethyl-1,3-hexane Diol 2.0% by mass, FS-300 (manufactured by DuPont) 2.5% by mass, Proxel LV (manufactured by Avecia) 0.2% by mass, 2-amino-2-ethyl-1,3-propanediol An appropriate amount of 5% by mass and ion-exchanged water was added to make 100% by mass, and then filtration was performed with a membrane filter having an average pore diameter of 0.8 μm. Thereafter, the solid content was adjusted to 12% by mass using ion-exchanged water. The ink composition was prepared as described above. The obtained ink composition had a viscosity at 25 ° C. of 9 mPa · s and a surface tension of 25 mN / m. The measurement of the viscosity was performed at 25 ° C. using a viscosity measuring device (manufactured by Toki Sangyo Co., Ltd., R500 rotational viscometer). The surface tension was measured at 25 ° C. using a surface tension measuring apparatus (CBVP-Z, manufactured by Kyowa Interface Science Co., Ltd.) and a platinum plate. (The viscosity measurement method and surface tension measurement method of ink and clear ink are the same in the following.)
Production Example 6: Magenta ink 1
Dimethylquinacridone pigment-containing polymer fine particle dispersion 20.0% by mass of Production Example 2, 3-
Methyl-1,3-butanediol 22.5% by mass, glycerin 9.0% by mass, 2-ethyl-1,3-hexanediol 2.0% by mass, FS-300 (manufactured by DuPont) 2.5% by mass , Proxel LV (manufactured by Avecia) 0.2% by mass, 2-amino-2-ethyl-1,3-
Propanediol 0.5% by mass and ion exchange water were added in an appropriate amount to 100% by mass, and then filtered with a membrane filter having an average pore size of 0.8 μm. Thereafter, the solid content was adjusted to 12% by mass using ion-exchanged water. The ink composition was prepared as described above. The obtained ink composition had a viscosity at 25 ° C. of 9 mPa · s and a surface tension of 25 mN / m.
Production Example 7: Yellow ink 1
Monoazo yellow pigment-containing polymer fine particle dispersion of Production Example 3 20.0% by mass, 3-methyl-1,3-butanediol 24.5% by mass, glycerin 8.0% by mass, 2-ethyl-1,3-hexane Diol 2.0% by mass, FS-300 (manufactured by DuPont) 2.5% by mass, Proxel LV (manufactured by Avecia) 0.2% by mass, 2-amino-2-ethyl-1,3-propanediol An appropriate amount of 5% by mass and ion-exchanged water was added to make 100% by mass, and then filtration was performed with a membrane filter having an average pore diameter of 0.8 μm. Thereafter, the solid content was adjusted to 12% by mass using ion-exchanged water. The ink composition was prepared as described above. The obtained ink composition had a viscosity at 25 ° C. of 9 mPa · s and a surface tension of 25 mN / m.
Production Example 8: Black ink 1
Carbon black dispersion 20.0% by mass of Production Example 4, 2-methyl-1,3-butanediol 22.5% by mass, glycerin 7.5% by mass, 2-pyrrolidone 2.0% by mass, 2-ethyl- 1,3-hexanediol 2.0 mass%, R- (OCH ₂ CH ₂ ) _n OH (wherein R is an alkyl group having 12 carbon atoms, n = 9) 2.0 mass%, Proxel LV ( (Avecia) 0.2 mass%, 2-amino-2-ethyl-1,3-propanediol 0.5 mass%, and an appropriate amount of ion-exchanged water are added to make 100 mass%. Filtration was performed with an 8 μm membrane filter. Thereafter, the solid content was adjusted to 12% by mass using ion-exchanged water. The ink composition was prepared as described above. The obtained ink composition had a viscosity at 25 ° C. of 9 mPa · s and a surface tension of 25 mN / m.

-Adjustment of clear ink 1-
The components shown below were mixed, sufficiently stirred and dissolved, and then filtered under pressure using a fluoropore filter (trade name: manufactured by Sumitomo Electric Co., Ltd.) having a pore size of 0.45 μm to prepare Clear Ink Set 1. .

Julimer ET315 (alkyl acrylate copolymer emulsion, Nippon Pure Chemical Industries, Ltd.)
(Adjusted to a solid content of 33% by mass) 60.0% by mass
Glycerin 10.0% by mass
3-Methyl-1,3-butanediol 25.0% by mass
2-ethyl-1,3-hexanediol 2.0% by mass
FS-300 (manufactured by DuPont) 2.3 mass%
Proxel LV (Avecia) 0.2% by mass
2-Amino-2-ethyl-1,3-propanediol 0.5% by mass
-Adjustment of clear ink 2-
The components shown below were mixed, sufficiently stirred and dissolved, and then subjected to pressure filtration using a fluoropore filter (trade name: manufactured by Sumitomo Electric Co., Ltd.) having a pore size of 0.45 μm to prepare a clear ink set 2. .
Boncoat CG-5010 (acrylic-urethane resin emulsion, manufactured by Dainippon Ink & Chemicals, Inc.)
(Adjusted to a solid content of 33% by mass) 60.0% by mass
Glycerin 10.0% by mass
3-Methyl-1,3-butanediol 25.0% by mass
2-ethyl-1,3-hexanediol 2.0% by mass
FS-300 (manufactured by DuPont) 2.3 mass%
Proxel LV (Avecia) 0.2% by mass
2-Amino-2-ethyl-1,3-propanediol 0.5% by mass
-Adjustment of clear ink 3-
The components shown below were mixed, sufficiently stirred and dissolved, and then filtered under pressure using a fluoropore filter having a pore size of 0.45 μm (trade name: manufactured by Sumitomo Electric Co., Ltd.) to prepare Clear Ink 3. The viscosity was adjusted to 6 mPa · s.
Julimer ET315 (alkyl acrylate copolymer emulsion, Nippon Pure Chemical Industries, Ltd.)
(Adjusted to a solid content of 33% by mass) 18.2% by mass
3-Methyl-1,3-butanediol 35.0% by mass
2-ethyl-1,3-hexanediol 2.0% by mass
FS-300 (manufactured by DuPont) 2.3 mass%
Proxel LV (Avecia) 0.2% by mass
2-amino-2-ethyl-1,3-propanediol 0.5% by mass,
-Adjustment of clear ink 4-
The components shown below were mixed, sufficiently stirred and dissolved, and then filtered under pressure using a fluoropore filter (trade name: manufactured by Sumitomo Electric Co., Ltd.) having a pore size of 0.45 μm to prepare clear ink 4. The viscosity was adjusted to 28 mPa · s.

Julimer ET315 (alkyl acrylate copolymer emulsion, Nippon Pure Chemical Industries, Ltd.)
(Adjusted to a solid content of 33% by mass) 60.0% by mass
Glycerin 35.0% by mass
2-ethyl-1,3-hexanediol 2.0% by mass
FS-300 (manufactured by DuPont) 2.3 mass%
Proxel LV (Avecia) 0.2% by mass
2-Amino-2-ethyl-1,3-propanediol 0.5% by mass
-Adjustment of clear ink 1/2-
Clear ink 1/2 was prepared by mixing clear ink 1 and clear ink 2 at a mass ratio of 1: 1.

-Media production-
Production of Support 1-LBKP 80 parts by mass-NBKP 20 parts by mass-Light calcium carbonate (trade name: TP-121, manufactured by Okutama Kogyo Co., Ltd.) 10 parts by mass-Aluminum sulfate 1.0 part by mass-Amphoteric starch (trade name) : Cato 3210, manufactured by Nippon NSC Co., Ltd.) 1.0 part by mass-Neutral rosin sizing agent 0.3 part by mass (trade name: NeuSize M-10, manufactured by Harima Chemicals Co., Ltd.)
Yield improver (trade name: NR-11LS, manufactured by Hymo Co., Ltd.) 0.02 parts by weight A 0.3% by weight slurry of the above composition was made with a long paper machine and machine calendered to a basis weight of 79 g / m ² support 1 was produced. In addition, in the size press process of the papermaking process, the oxidized starch aqueous solution was applied so that the solid content was 1.0 g / m ² per side.
Media production example (Recording paper 1)
The prepared support 1 has 70 parts by mass of kaolin having a particle size of 2 μm or less as a pigment of 97% by mass, 30 parts by mass of heavy calcium carbonate having an average particle size of 1.1 μm, and a glass transition temperature (Tg) as an adhesive. Add 5 parts by weight of styrene / butadiene copolymer emulsion at -5 ° C., 1 part by weight of phosphate esterified starch, 0.5 part by weight of calcium stearate as an auxiliary agent, and add water to add a solid content concentration of 60%. The working fluid was adjusted.

This coating solution is coated on both sides of the above base paper using a blade coater so that the coating layer thickness per side is 10 μm, dried with hot air, and then subjected to supercalender treatment at a linear pressure of 20 kg / cm. Gloss coated paper (Recording paper 1) was obtained.
Examples 1-7, Comparative Examples 1-7
Using ink set 1 consisting of cyan ink 1, magenta ink 1, yellow ink 1 and black ink 1 manufactured in Manufacturing Examples 5 to 8 and the media shown in Table 1, it has 300 dpi and a nozzle resolution of 384 nozzles. Printing was performed at an image resolution of 600 dpi using a drop-on-demand printer prototype. The large droplet size was 20 pl, the medium droplet size was 10 pl, and the small droplet size was 2 pl. The total amount of secondary colors was regulated to 140%, and the amount of adhesion was regulated. At the time of printing, solid images and characters were printed at a total ink amount of 300 dots by 12 g / m ² . The obtained image was evaluated for image gloss. Furthermore, the clear ink shown in Table 1 was applied to the media after the image formation with the adhesion amount shown in Table 1. As the coating device, an inkjet recording device (GX5000) in which an ink cartridge was filled with clear ink was used, and clear ink was applied to the entire medium using graphics of MS word solid image in glossy paper-clean mode. Further, the image gloss after the gloss treatment was evaluated.

<Evaluation items and measurement methods>
-Absorption-
About each recording medium, the absorption amount of the ink of an Example and a comparative example was measured at 25 degreeC50% RH using the dynamic scanning absorption meter (K350 series D type, Kyowa Seiko Co., Ltd. make). The amount of absorption at a contact time of 500 ms was determined by interpolation from the measured value of the amount of absorption at the contact time adjacent to each contact time. In measuring the amount of absorption, cyan ink of each ink set was used.

-Glossiness-
Using a micro-gloss gloss meter (BYK-Gardner), the 60 ° gloss of the green solid part was measured. The difference between before and after the clear ink treatment was evaluated.
In addition, when the clear ink treatment does not cause uneven glossiness, ○, when gloss unevenness occurs, or when defects such as repellency occur, visually acceptable items are Δ, unacceptable items X.

-Image abrasion resistance-
For the cyan solid image portion of each image print, after printing for 24 h, a clock meter (CM-1 type) was used, and a white cotton cloth (JISL0803 cotton No. 3) was used as a friction element on a double-sided adhesive foam tape (# 4016 manufactured by 3M Corporation). 1.6), the density of the color material adhered to the cotton cloth after reciprocating five times was measured using a spectrocolorimetric densitometer (Model-938 manufactured by X-Rite Co., Ltd.).

(Evaluation criteria)
◯: The concentration is 0.05 or less and is at a level where there is no practical problem. ×: The concentration is larger than 0.05 and there is a problem in practical use. Or the improvement effect is not recognized.

-Comprehensive evaluation-
Among each item, those where the image abrasion resistance was not improved were marked with ×, and those where the improvement effect was recognized were marked with ○.

Among those improved in image abrasion resistance, those where defects were found due to background abrasion resistance, uneven gloss, etc. were marked with Δ.

The details of each medium in Table 1 are as follows.
* Mirror coat platinum: Cast paper manufactured by Oji Paper Co. * POD gloss: Coated paper for electrophotography manufactured by Oji Paper Co., Ltd. * Chrispia: Photo paper for ink jet manufactured by Seiko Epson Co. Also, details of each clear ink in Table 1 are as follows. It is as follows.
* Gloss Enhancer: Clear ink for inkjet manufactured by Seiko Epson * Gloss Optimizer: Clear ink for inkjet manufactured by Hewlett-Packard

  The recording method of the present invention can provide a printed matter having a texture close to that of a general silver salt photograph at high speed, and can be suitably used for an ink recorded matter, an ink jet recording apparatus, and an ink jet recording method. Further, the obtained printed matter is excellent in image abrasion resistance, and there is no problem in handling immediately after printing.

  The recording method of the present invention can be applied to various types of recording that require an ink jet recording method, and is particularly suitable for, for example, an ink jet recording printer, a facsimile apparatus, a copying apparatus, a printer / fax / copier multifunction machine, and a printing machine. Can be applied to.

It is the schematic which shows an example of the ink cartridge of this invention. FIG. 2 is a schematic view including a case (exterior) of the ink cartridge of FIG. 1. FIG. 4 is a perspective explanatory view showing a state where an ink cartridge loading unit cover of the ink jet recording apparatus is opened. It is a schematic block diagram explaining the whole structure of an inkjet recording device. It is a schematic enlarged view which shows an example of the inkjet head of this invention. It is an element enlarged view showing an example of an ink jet head of the present invention. It is a principal part expanded sectional view which shows an example of the inkjet head of this invention.

(Fig. 1 and Fig. 2)
200 Ink cartridge 241 Ink bag 242 Ink inlet 243 Ink outlet 244 Cartridge exterior (FIGS. 3, 4, and 5)
101 apparatus main body 102 paper feed tray 103 paper discharge tray 104 ink cartridge loading unit 105 operation unit 111 upper cover 112 front surface 115 front cover 131 guide rod 132 stay 133 carriage 134 recording head 135 sub tank 141 paper placement unit 142 paper 143 paper supply roller 144 Separation pad 145 Guide 151 Conveying belt 152 Counter roller 153 Conveying guide 155 Pressure roller 156 Charging roller 157 Conveying roller 158 Densation roller 161 Guide member 171 Separating claw 172 Discharging roller 173 Discharging roller 181 Double-sided paper feeding unit 182 Manual feeding Paper part 200 Ink cartridge (FIGS. 6 and 7)
1b Common liquid chamber 2a Liquid resistance portion 2b Pressurizing liquid chamber 2c Communication port 2d Partition wall 3a Nozzle 5f Drive portion 5g Support portion 6a Protruding portion 6b Diaphragm 6c Ink inlet 10 Frame 20 Channel plate 30 Nozzle plate 40 Base 50 Multilayer piezoelectric element 60 Diaphragm 70 Adhesive layer

Claims (9)

A particulate colorant and an interface on a medium having a coating layer containing at least one inorganic pigment and a styrene-butadiene copolymer on at least one surface of a support mainly composed of cellulose pulp. An image forming step of forming an image by flying an ink having a solid content of 6% by mass or more containing an activator and water;
A post-processing step of applying a clear ink having a solid content of 10% by mass or more containing fine resin particles and water to a medium after image formation,
A recording method, wherein the amount of ink absorbed into the medium at a contact time of 500 ms by a scanning liquid absorptiometer is 1 ml / m ² or more and 10 ml / m ² or less. The recording method according to claim 1, wherein the adhesion amount of the clear ink is 0.3 g / m ² or more and 5 g / m ² or less by dry weight. The inkjet recording method according to claim 1, comprising two types of clear ink, wherein the application is performed while changing the usage rate of the clear ink in accordance with the background gloss of the medium in the post-processing step. The recording method according to any one of claims 1 to 3, wherein the 60 ° glossiness defined in JIS-ZS-8741 of the media is 50% or more. The recording method according to claim 1, wherein the surfactant is a fluorine-based surfactant. The clear ink used in the recording method according to claim 1, wherein the clear ink contains 20% by mass or more of a wetting agent and has a viscosity at 25 ° C. of 5 mPa · s to 30 mPa · s. The clear ink used in the recording method according to claim 1, wherein the clear ink contains a surfactant and has a surface tension at 25 ° C. of 15 to 30 mN / m. ink. An ink used in the recording method according to claim 1. A medium used in the recording method according to claim 1.

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