JP2007246840A - Ink composition for inkjet recording, method for manufacturing planographic printing plate and planographic printing plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink composition for inkjet recording, a method for manufacturing planoographic printing plate and a planographic printing plate which exhibits high image quality and satisfactory plate wear without bleeding of a discharge image. <P>SOLUTION: The ink composition for inkjet recording comprises (A) a disperse medium, (B) a resin particles, (C) an electriccharge-controlling agent, (D) a polymerization initiator, and (E) a polymerizable compound. The planographic printing plate is obtained by the manufacturing method comprising a process for discharging the ink composition onto an ink acceptor, and a process for curing the ink composition by the irradiation of (b) discharged ink composition with heat or heat and light, so as to form a hydrophobic image of the ink composition onto the ink acceptor. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ink composition for inkjet recording, a method for producing a lithographic printing plate, and a lithographic printing plate.

  As an image recording method for forming an image on a recording medium based on an image data signal, there are an electrophotographic method, a sublimation type and a melt type thermal transfer method, an ink jet method and the like. In particular, the ink jet system is an inexpensive apparatus and ejects ink only to a required image portion to form an image directly on a recording medium. Therefore, the ink can be used efficiently and the running cost is low. Furthermore, there is little noise and it is excellent as an image recording method.

  Conventionally, in producing a lithographic printing plate, using a so-called PS plate having a configuration in which a lipophilic photosensitive resin layer is provided on a hydrophilic support, the photosensitive resin layer is exposed imagewise, A method of forming an image by improving or decreasing the solubility of the exposed portion in an alkaline developer and dissolving and removing the non-image portion was employed. However, in recent years, digitization techniques for electronically processing, storing, and outputting image information using a computer have become widespread, and a new image output method corresponding to the technique has been demanded. In particular, a method capable of producing a printing plate without undergoing treatment with a developing solution has been studied, and a method of directly producing a lithographic printing plate using an ink composition for inkjet recording has been studied. This is preferably a printing plate having a desired image (preferably a hydrophobic image) by ejecting the ink imagewise on the surface of the hydrophilic support by an ink jet method or the like and curing it (for example, (See Patent Documents 1 to 3.)

  As the ink jet method, a piezo method is generally used. Piezo inks include water-based inks, solvent-based inks, and radiation curable inks. Each ink can suppress the spread of ink droplets on a recording paper that has been treated to absorb the ink, but has a hydrophilic surface and a non-ink-absorbing support (aluminum) like a lithographic printing plate. , PET, etc.), the spread of the landed ink droplets becomes remarkable, and the image dots become large.

  Patent Document 4 contains a reactive diluent and a photopolymerization initiator as a curable component, and further, an oil-based ink containing a solvent and a dye is applied to a printing plate support by an inkjet method to form an image. A plate making method is disclosed, wherein an image portion is cured by light irradiation. However, in the above Patent Documents 1 to 4, liquid ink is used at room temperature in common, but there is a problem that the resolution is reduced due to ink bleeding.

  In order to improve the disadvantages of such liquid ink at room temperature, a hydrophobic material that is solid at room temperature is used as an ink composition by melting it with a heating head. A plate making method for forming an image line portion is disclosed (for example, see Patent Document 5). Since the molten ink is cooled and solidified when discharged onto the plate, there is an advantage that the problem of bleeding is avoided as compared with the case of using a water-based or oil-based liquid ink. In general, however, such heat-dissolvable hydrophobic materials do not have sufficient hardness after solidification at room temperature, and the resulting printing plate is inferior in printing durability. Therefore, the printing durability of inks that are solid at room temperature is improved. For this purpose, a technique further containing light and an electron beam polymerizable composition has been proposed (see, for example, Patent Document 6). According to this method, although the strength of the formed image portion is improved, the apparatus for electron beam polymerization used for curing becomes large and requires high energy, so that a simple ink jet method is applied to plate making. Will be reduced.

On the other hand, since the charged particles in the ink are condensed and ejected in the ink jet method, the dispersion medium contained in the ink droplets is small, so the spread of the ink droplets landed on the support having a hydrophilic surface such as a lithographic printing plate Is small and has high image quality. However, when used for lithographic printing, the oleophilic particles on which the ink image is formed must be dried or fused on a support having a hydrophilic surface by heat, but the adhesion is weak and the printing durability is insufficient. This is the current situation.
As described above, even if various ink-jet inks are used, a lithographic printing plate based on an ink-jet method that does not bleed in an ejected image and has high image quality and satisfies printing durability has not yet been achieved.
JP-A-7-304278 JP-A-8-324145 Japanese Patent Laid-Open No. 9-024599 Japanese Patent No. 2542500 JP-A-9-58144 Japanese Patent Laid-Open No. 9-29926

  Accordingly, it is an object of the present invention to provide an ink composition for inkjet recording, a lithographic printing plate production method, and a lithographic printing plate that are free from bleeding in the ejected image and satisfy the printing durability.

The present invention is as follows.
(1) An ink composition for inkjet recording, comprising at least (A) a dispersion medium, (B) resin particles, (C) a charge control agent, (D) a polymerization initiator, and (E) a polymerizable compound. object.
(2) The ink composition for ink jet recording according to (1), wherein the resin particles (B) are colored with a colorant.
(3) (a) a step of ejecting the ink composition for ink jet recording described in (1) or (2) onto an ink receptor, and (b) heat or heat on the ejected ink composition And a step of forming a hydrophobic image of the ink composition on the ink receptor by applying light to cure the ink composition.
(4) A lithographic printing plate produced by the method for producing a lithographic printing plate as described in (3) above.

  According to the present invention, it is possible to provide an ink composition for inkjet recording, a lithographic printing plate production method, and a lithographic printing plate that are free from bleeding in the ejected image and satisfy the printing durability.

The present invention will be further described below. First, each component of the composition of the present invention will be described.
(A) Dispersion medium As the dispersion medium used in the ink composition of the present invention, any solvent such as a non-aqueous system, a polar organic solvent system, or a mixed solvent system of a polar organic solvent and water can be used. Non-aqueous solvents include linear or branched aliphatic hydrocarbons, alicyclic hydrocarbons, or aromatic hydrocarbons, halogen substitution products of these hydrocarbons, silicone oils, and the like. For example, hexane, heptane, octane, isooctane, decane, isodecane, decalin, nonane, dodecane, isododecane, cyclohexane, cyclooctane, cyclodecane, toluene, xylene, mesitylene, Isopar C, Isopar E, Isopar G, Isopar H, Isopar L, Isopar M, Isopar P (Isoper: trade name of Exxon), Shellzol 70, Shellzol 71 (Shellsol: trade name of Shell Oil), Amsco OMS, Amsco 460 solvent (Amsco: Trade name of Spirits), KF -96L (trade name of Shin-Etsu Silicone) or the like can be used alone or in combination.

Examples of a polar organic solvent or a mixed system of an aqueous system and a polar organic solvent are alcohols, ketones, and water, and alcohols are monohydric alcohols having 1 to 8 carbon atoms, such as methanol, ethanol, propanol, and butanol. I can do it. Examples of the polyhydric alcohol having 1 to 8 carbon atoms include ethylene glycol, propylene glycol, glycerin, cellosolve and the like. Furthermore, examples of the polyhydric alcohol ester include ethylene glycol monoalkyl ether acetate, diethylene glycol monoalkyl ether acetate, and triethylene glycol monoalkyl ether acetate.
Of these, non-aqueous solvents are preferable. In particular, a dispersion medium containing isopar as an insulating solvent as a main component is preferable, and the content of the dispersion medium may be appropriately selected depending on the ink composition, but is generally in the range of 30 to 99% by mass. .

(B) Resin Particles The (B) resin particles used in the present invention are oleophilic resin particles having printing ink fillability, and are resin particles that can be charged with a charge adjusting agent described below. As the resin particles suitably used, particles produced by the polymerization granulation method or the wet dispersion method shown below are preferable. In particular, from the viewpoint of inkjet, a polymerization granulation method in which the particle diameter is uniform and the charge density of individual particles is uniform is preferable. Hereinafter, the resin particles obtained by the polymerization granulation method will be described.

The resin particles (specific particles) obtained by the polymerization granulation method in the present invention preferably have a volume average particle size of 0.2 to 5.0 μm, and (A) resin particles dispersible in the dispersion medium. Although it may be sufficient, it is preferable that it is a particle obtained by the following method.
That is, the specific particles in the present invention may include (a) at least one (b) monofunctional monomer in a non-aqueous solvent, (c) a dispersion stabilizing resin (hereinafter referred to as a dispersant). ) And polymerized and granulated by polymerization, and a volume average particle size of 0.2 to 5.0 μm is preferable.
Hereinafter, the specific method for polymerizing and granulating specific particles of the present invention will be described in detail.

[(A) Nonaqueous solvent]
Here, (a) the non-aqueous solvent is a linear or branched aliphatic hydrocarbon, alicyclic hydrocarbon, or aromatic hydrocarbon, and a halogen-substituted product of these hydrocarbons (halogenated hydrocarbon). Type). Specifically, octane, isooctane, decane, isodecane, decalin, nonane, dodecane, isododecane, cyclohexane, cyclooctane, cyclodecane, benzene, toluene, xylene, mesitylene, Isopar E, Isopar G, Isopar H, Isopar L (Isopar; Exxon product name), Shellsol 70, Shellzol 71 (Shellsol; Shell Oil product name), Amsco OMS, Amsco 460 solvent (Amsco; Spirits product name), methylene dichloride, chloroform, carbon tetrachloride , Dichloroethane, methyl chloroform and the like can be used alone or in combination.

In addition to the above hydrocarbon compounds and their halogen-substituted products, the following non-hydrocarbon compounds can also be mixed and used. Examples of compounds that can be mixed include alcohols (for example, methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, and fluorinated alcohol), ketones (for example, acetone, methyl ethyl ketone, cyclohexanone, and the like), and carboxylic acid esters (for example, acetic acid). Methyl, ethyl acetate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate, etc.), ethers (eg, diethyl ether, dipropyl ether, tetrahydrofuran, dioxane, etc.), halogenated hydrocarbons (eg, methylene dichloride, Chloroform, carbon tetrachloride, dichloroethane, methyl chloroform and the like).

In the present invention, since the step (A) of replacing the dispersion medium, which constitutes the ink composition, is omitted, the (a) non-dispersion which is the same as (A) the dispersion medium is usually performed at the granulation stage of the specific particles. It is preferable to use an aqueous solvent.
In the case of drawing an image using the electrostatic ink jet recording system, from the viewpoint of lowering the dielectric constant of the dispersion medium, the non-hydrocarbon compound used by mixing with the above hydrocarbon compounds and their halogen substitution products. A lower ratio is preferred. Therefore, when (B) specific particles are prepared using (a) a non-aqueous solvent similar to (A) the dispersion medium, the non-hydrocarbon compound is mixed with the hydrocarbon compounds and their halogen substitution products. When the dielectric constant is 5.0 or more, (B) a method of removing the non-hydrocarbon compound mixed when synthesizing the specific particles so as to be 5.0 or less under heating or reduced pressure, Alternatively, it is preferable to increase the ratio of the hydrocarbon compound and decrease the dielectric constant using a method of replacing the supernatant using a centrifugal separator.

The amount of these (a) nonaqueous solvents used is preferably in the range of 80 to 0.01% by mass with respect to the total mass of the mixed solution used in the synthesis, that is, solids in the mixed solution. The minutes are preferably in the range of 20 to 99.99%. Moreover, it is more preferable that it is the range of 70-0.1 mass%, and it is still more preferable that it is the range of 60-1 mass%.
(A) When content of a nonaqueous solvent is less than 0.01 mass%, in addition to (B) the particle size of specific particle not becoming a desired magnitude | size, monodispersibility will fall. On the other hand, when it is more than 80% by mass, the aggregation of the specific particles (B) occurs, and the monodispersibility and dispersibility are lowered.

[(B) Monofunctional monomer]
The (b) monofunctional monomer (hereinafter sometimes simply referred to as “(b) monomer”) in the present invention is (a) soluble in a non-aqueous solvent but polymerized. If it is a monofunctional monomer insolubilized by this, it will not specifically limit. Specific examples include monomers represented by the following general formula (I).

In the general formula (I), T ¹ is —COO—, —OCO—, —CH ₂ OCO—, —CH ₂ C.
OO—, —O—, —CONHCOO—, —CONHOCO—, —SO ₂ —, —CON (W ¹ ) —, —SO ₂ N (W ¹ ) —, or a phenylene group (hereinafter referred to as “-Ph”). -". The phenylene group represents 1,2-, 1,3- and 1,4-phenylene groups). Here, W ¹ is a hydrogen atom or an optionally substituted aliphatic group having 1 to 20 carbon atoms (for example, methyl group, ethyl group, propyl group, butyl group, 2-chloroethyl group, 2-bromoethyl group, 2 -Cyanoethyl group, 2-hydroxyethyl group, benzyl group, chlorobenzyl group, methylbenzyl group, methoxybenzyl group, phenethyl group, 3-phenylpropyl group, dimethylbenzyl group, fluorobenzyl group, 2-methoxyethyl group, 3- Methoxypropyl group and the like).

D ¹ represents a hydrogen atom, a halogen atom, or an optionally substituted aliphatic group having 1 to 20 carbon atoms. As this aliphatic group, for example, methyl group, ethyl group, propyl group, butyl group, 2-chloroethyl group, 2,2-dichloroethyl group, 2,2,2-trifluoroethyl group, 2-bromoethyl group, 2-glycidylethyl group, 2-hydroxyethyl group, 2-hydroxypropyl group, 2,3-dihydroxypropyl group, 2-hydroxy-3-chloropropyl group, 2-cyanoethyl group, 3-cyanopropyl group, 2-nitroethyl Group, 2-methoxyethyl group, 2-methanesulfonylethyl group, 2-ethoxyethyl group, N, N-dimethylaminoethyl group, N, N-diethylaminoethyl group, trimethoxysilylpropyl group, 3-bromopropyl group, 4-hydroxybutyl group, 2-furfurylethyl group, 2-thienylethyl group, 2-pyridylethyl group, 2-mol Linoethyl group, 2-carboxyethyl group, 3-carboxypropyl group, 4-carboxybutyl group, 2-phosphoethyl group, 3-sulfopropyl group, 4-sulfobutyl group, 2-carboxyamidoethyl group, 3-sulfoamidopropyl group 2-N-methylcarboxamidoethyl group, cyclopentyl group, chlorocyclohexyl group, dichlorohexyl group and the like.

d ¹ and d ² may be the same or different from each other, and are a hydrogen atom, a halogen atom, a cyano group, a hydrocarbon group having 1 to 20 carbon atoms, —COO—Z ¹ , or a hydrocarbon group having 1 to 20 carbon atoms. —COO-Z ¹ [wherein Z ¹ represents a hydrocarbon group having 1 to 22 carbon atoms].

Specific examples of (b) monofunctional monomers include vinyl esters or allyls of aliphatic carboxylic acids having 1 to 20 carbon atoms (such as acetic acid, propionic acid, butyric acid, monochloroacetic acid, and trifluoropropionic acid). Esters; alkyl esters or amides having 1 to 10 carbon atoms of unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid and maleic acid (as the alkyl group, for example, methyl Group, ethyl group, propyl group, butyl group, 2-chloroethyl group, 2-bromoethyl group, 2-fluoroethyl group, trifluoroethyl group, 2-hydroxyethyl group, 2-cyanoethyl group, 2-nitroethyl group, 2-methoxy Ethyl group, 2-methanesulfonylethyl group, 2-benzenesulfonylethyl group, 2- (N, N-dimethylamino) Til group, 2- (N, N-diethylamino) ethyl group, 2-carboxyethyl group, 2-phosphoethyl group, 4-carboxybutyl group, 3-sulfopropyl group, 4-sulfobutyl group, 3-chloropropyl group, 2- Hydroxy-3-chloropropyl group, 2-furfurylethyl group, 2-pyridinylethyl group, 2-thienylethyl group, trimethoxysilylpropyl group, 2-carboxyamidoethyl group, etc.); styrene derivatives (for example, styrene, vinyltoluene) , Α-methylstyrene, vinylnaphthalene, chlorostyrene, dichlorostyrene, bromostyrene, vinylbenzenecarboxylic acid, vinylbenzenesulfonic acid, chloromethylstyrene, hydroxymethylstyrene, methoxymethylstyrene, N, N-dimethylaminomethylstyrene, vinyl benzene Carboxamide, vinylbenzenesulfoamide, etc.); unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid and itaconic acid; cyclic anhydrides of maleic acid and itaconic acid; acrylonitrile; methacrylonitrile; Heterocyclic compounds containing a double bond group (specifically, for example, compounds described in “Polymer Data Handbook -Basic Edition” edited by the Society of Polymer Science, p. 175-184, Kaoru Baifu (1986), for example, N -Vinylpyridine, N-vinylimidazole, N-vinylpyrrolidone, vinylthiophene, vinyltetrahydrofuran, vinyloxazoline, vinylthiazole, N-vinylmorpholine and the like.
These monofunctional monomers may be used alone or in combination of two or more.

The amount of these (b) monofunctional monomers used is preferably 10% by mass or more, more preferably 15% by mass or more, based on the total solid content in the mixed solution used in the synthesis. Is more preferable, and it is still more preferable that it is 20 mass% or more. In addition, the upper limit of the amount (b) of the monofunctional monomer used is preferably 99% by mass or less from the viewpoint of monodispersity and dispersion stability of the obtained (B) specific particles, and is 95% by mass. The following is more preferable.
When the content of the (b) monofunctional monomer is less than 10% by mass, the (B) specific particles are difficult to precipitate from the (a) non-aqueous solvent, so that the synthesis becomes difficult. Moreover, monodispersity also falls.

[(C) Dispersion stabilizing resin (dispersant)]
The (c) dispersion stabilizing resin (dispersant) used when granulating (B) specific particles in the present invention will be described.
This (c) dispersant is obtained by polymerizing (b) a monofunctional monomer in (a) a non-aqueous solvent, and (a) a polymer insoluble in the non-aqueous solvent as a stable resin. Used to make dispersions.
In the present invention, (c) the dispersion stabilizing resin (dispersant) may be used in an amount of 1 to 50% by mass based on (B) the monofunctional monomer used for the synthesis of (B) specific particles. Preferably, it is 5-40 mass% more preferably.

  As the dispersant in the present invention, a random copolymer, comb-type copolymer, star-type copolymer, partially cross-linked copolymer, cross-linkable group-containing copolymer, which is soluble in the above-mentioned (A) dispersion medium. Conventional dispersion stabilizers such as coalescence can be used. Hereinafter, the crosslinkable group-containing copolymer preferably used in the present invention will be exemplified.

(Crosslinkable group-containing copolymer)
The crosslinkable group-containing copolymer in the present invention is, as shown by the following general formula (VII), at least (a) a copolymer component (X component) that is soluble in a non-aqueous solvent, and at the end of the side chain. , A random copolymer containing a specific component obtained by polymerization granulation and a copolymer component (Y component) having a polymerizable double bond group that can be copolymerized. Therefore, this crosslinkable group-containing copolymer is a resin that is soluble in the dispersion medium (A).
Here, X component in general formula (VII) may be comprised from the single copolymerization component, and may be comprised from the 2 or more types of copolymerization component. The same applies to the Y component.

In the general formula (VII), R ¹ represents an alkyl group or alkenyl group having 10 to 32 carbon atoms, which may be linear or branched. Specifically, decyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, octadecyl group, eicosanyl group, docosanyl group, decenyl group, dodecenyl group, tridecenyl group, hexadecenyl group, octadecenyl group, eicosenyl group, A dococenyl group, a linoleyl group, etc. are mentioned.
b ¹ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms (methyl group, ethyl group, propyl group, butyl group), preferably a hydrogen atom or a methyl group.
X ¹ and X ² are each independently a single bond, —COO—, —CONH—, —CON (E ² ) — [wherein E ² is preferably an aliphatic group having 1 to 22 carbon atoms (aliphatic group). Represents an alkyl group, an alkenyl group, an aralkyl group, or the like. ], -OCO-, -CH
₂ represents OCO- or -O-. More preferably -COO -, - CONH- or -CON (E ²⁾ - represents a.

In the general formula (VII), d ¹ , d ² , e ¹ , and e ² each independently represent a hydrogen atom, a halogen atom, a cyano group, or an alkyl group. Specific examples of the alkyl group include specific examples of the aliphatic group having 1 to 20 carbon atoms which is represented by D ¹ in the general formula (I).

W represents a linking group containing a carbon atom and / or a hetero atom. Here, examples of the hetero atom include an oxygen atom, a sulfur atom, a nitrogen atom, and a silicon atom.
Examples of the linking group include those composed of any combination of a carbon-carbon bond (single bond or double bond), a carbon-heteroatom bond, a heteroatom-heteroatom bond atomic group, a heterocyclic group, and the like. Specific examples include the divalent groups listed below.

In the above divalent group examples, r ^{1 to} r ⁴ are each a hydrogen atom, a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom, etc.), a cyano group, a hydroxyl group, or an alkyl group (for example, Methyl group, ethyl group, propyl group, etc.).
r ^{5 to} r ⁷ each independently represents a hydrogen atom, an alkyl group (for example, a methyl group, an ethyl group, a propyl group, a butyl group, or the like).
r ^{8 to} r ⁹ are each independently a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms (for example, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, benzyl group, phenethyl group, A phenyl group, a tolyl group, etc.), or -Or ¹⁰ (r ¹⁰ represents the same content as the hydrocarbon group in r ⁸ ).

Heterocyclic groups that can constitute W include heteroatoms containing heteroatoms such as oxygen, sulfur, and nitrogen atoms (eg, thiophene ring, pyridine ring, pyran ring, imidazole ring, benzimidazole ring, furan ring, piperidine) Ring, pyrazine ring, pyrrole ring, piperazine ring, etc.)
Etc.

In addition, the connecting chain composed of [—X ¹ —W—X ² —] in the Y component of the general formula (VII) is
The total number of atoms is preferably 8 or more. As the number of atoms of the connecting main chain in this connecting chain, for example, when X ¹ represents —COO— or —CONH—, an oxo group (═O
Group) and hydrogen atoms are not included as the number of atoms, and carbon atoms, ether type oxygen atoms, and nitrogen atoms constituting the connecting main chain are included as the number of atoms. Therefore, -COO- and -CONH- are counted as 2 atoms.

Although the specific example [(Y-1)-(Y-12)] about the copolymerization component (Y component) which has a polymerizable double bond group is shown below, this invention is not limited to these. .
In the following formula, each symbol represents the following contents.

The crosslinkable group-containing copolymer in the present invention can be easily synthesized by a conventionally known synthesis method. That is, as a method for introducing a copolymer component (Y component) having a polymerizable double bond group into a resin, a “specific reactive group” (for example, —OH, —COOH, —SO ₃ ) is used in advance. H, —NH ₂ , —SH, —PO ₃ H ₂ , —NCO, —NCS, —COCl, —SO ₂ Cl, an epoxy group, etc.) are used as the X component in the general formula (VII). A method of introducing a polymerizable reactive group by a polymer reaction after reacting a reactive reagent containing a polymerizable double bond group after the polymerization reaction with the corresponding monomer is mentioned.
Specifically, P.I. Dryfuss & R.D. P. Quirk, Encycl. Polym. Sci, Eng. , 7.551 (1987), Yoshiki Nakajo, Yuya Yamashita “Dyes and Drugs”, 30.232 (1985), Akira Ueda, Susumu Nagai, “Chemical and Industrial”, 60.57 (1986), p. F. Rempp & E.M. Franta, Advances in Polymer Science, 58.1 (1984), Koichi Ito “Polymer Processing”, 35.262 (1986), V. A polymerizable double bond group can be introduced according to a method described in a review article such as Percec, Applied Polymer Science, 285.97 (1984) and literatures cited therein.

  In addition, as another method, a bifunctional monomer having different copolymerization reactivity in a radical polymerization reaction is used, and a polymerization reaction is performed together with a monomer corresponding to the X component. Examples thereof include a method described in JP-A No. 60-185962 for synthesizing a copolymer represented by the formula (VII).

  In the resin represented by the general formula (VII), the ratio of the X component and the Y component suppresses the gelation of the reaction mixture during the polymerization granulation reaction or the coarsening of the specific particles to be generated, and the specific ratio. From the viewpoint of dispersion stability and redispersibility of the particles, the polymerization ratio is 60/40 to 99/1, and preferably 85/15 to 98/2 mass ratio.

In addition, the crosslinkable group-containing copolymer used in the present invention may contain other repeating units as a copolymerization component together with each repeating unit represented by the general formula (VII). The other copolymer component may be any compound as long as it is composed of a monomer copolymerizable with a monomer corresponding to each repeating unit of the general formula (VII).
The other copolymerization component is used in a range not exceeding 20 parts by mass with respect to 100 parts by mass of all polymerization components. If it exceeds 20 parts by mass, the dispersibility of the specific particles in the present invention will deteriorate.

The mass average molecular weight (Mw) of the crosslinkable group-containing copolymer of the present invention is 5 × 10 ³ to 10 × 10 ⁶ , preferably 1 × from the viewpoints of storage stability, redispersibility, and dispersion stability. 10 ^{4 to} 2 × 10 ⁵ .

[Granulation method]
In order to produce (B) specific particles used in the present invention, generally, (c) a dispersant as described above and a monofunctional monomer (b) are combined in (a) a non-aqueous solvent. Heat polymerization may be performed in the presence of a polymerization initiator such as benzoyl peroxide, azobisisobutyronitrile, or butyl lithium.
Specifically, (i) (c) a dispersing agent, (b) a method of adding a polymerization initiator in a mixed solution of monomers, (ii) (c) in a solution in which the dispersing agent is dissolved (b) A method in which a monomer is dropped together with a polymerization initiator, or (iii) (c) in the mixed solution containing the total amount of the dispersing agent and (b) a part of the monomer, the remaining ( b) a method of adding a monomer, and further, (iv) (a) a method of adding (c) a dispersing agent, (b) a mixed solution of monomers together with a polymerization initiator in a non-aqueous solvent, etc. It can be manufactured using any method.

As for the quantity of a polymerization initiator, 0.1-20 mass% of the total amount of (b) monomer is preferable, More preferably, it is 0.5-10 mass%.
Moreover, superposition | polymerization temperature is about 40-180 degreeC, Preferably it is 50-120 degreeC. The reaction time is preferably 3 to 15 hours.

  When (a) the nonaqueous solvent used in the reaction is combined with a polar solvent such as the alcohols, ketones, ethers, esters, or the like, or (b) the monomer to be polymerized and granulated When unreacted substances remain, it is preferably removed by heating to a boiling point or higher of the solvent or monomer or by distilling off under reduced pressure.

  In addition, you may contain the coloring agent demonstrated below in (B) specific particle. As one of the methods for inclusion, there is a method of dyeing (B) specific particles with a preferable dye as described in JP-A-57-48738. Alternatively, as disclosed in JP-A-53-54029, other methods include (B) a method in which specific particles and a dye are chemically bonded, or Japanese Patent Publication No. 44-22955. As described in the above, there is a method of using a monomer containing a dye in advance to produce a dye-containing copolymer when it is produced by a polymerization granulation method.

The non-aqueous dispersed resin particles [(B) specific particles] produced as described above have a volume average particle size of 0.2 to 5.0 μm, are fine, and have a uniform particle size distribution. Moreover, from a viewpoint of dispersion stability, storage stability, and redispersibility, Preferably it is 0.3-4.0 micrometers, More preferably, it is 0.5-3.0 micrometers.
This volume average particle diameter is determined by CAPA-500 (trade name, manufactured by Horiba, Ltd.).

  In the present invention, (B) as a factor for controlling the particle size of the specific particles, (b) the type and concentration of the monofunctional monomer used, the type and concentration of the dispersant, the type of solvent and the concentration thereof The presence or absence of additives, the reaction temperature, and the like can be mentioned, and by appropriately adjusting these, (B) specific particles having a desired particle diameter can be obtained.

In addition, the mass average molecular weight of the (B) specific particles in the present invention is preferably 1 × 10 ³ to 1 × 10 ⁶ , more preferably 3 × 10 ^{3 to} 5 × 10 ⁵ , most preferably 5 ×. 10 ³ to 1 × 10 ⁵ .
The specific particle (B) in the present invention has an elastic modulus at room temperature (10 to 30 ° C. in the present invention) as a thermal property of 1.0 × 10 ⁷ or more, and a fixing temperature (in the present invention). Is preferably in the range of 5.0 × 10 ⁶ or less at 80 to 150 ° C., and in particular, the modulus of elasticity at room temperature is 1.0 × 10 ⁸ or more and 1 at the fixing temperature. More preferably, it is in the range of 0.0 × 10 ⁶ or less.

  In the ink composition of the present invention, the content of the (B) specific particles is preferably in the range of 90 to 1% by mass, and in the range of 80 to 20% by mass with respect to the total mass of the ink composition. Is more preferable, and it is still more preferable that it is the range of 70-3 mass%.

Next, resin particles (second specific particles) obtained by the wet dispersion method in the present invention will be described. The second specific particle can be, for example, a particle obtained by coating a colorant described below with a lipophilic substance (coating polymer).
Examples of lipophilic substances used in the present invention include rosins, rosin-modified phenol resins, alkyd resins, (meth) acrylic polymers, polyurethanes, polyesters, polyamides, polyethylenes, polybutadienes, polystyrenes, polyvinyl acetates, and polyvinyl alcohols. Examples include acetal-modified products and polycarbonate. Among these, from the viewpoint of ease of particle formation, the mass average molecular weight is in the range of 2,000 to 1,000,000 and the polydispersity (mass average molecular weight / number average molecular weight) is 1.0. Polymers in the range of ~ 5.0 are preferred. Further, from the viewpoint of ease of fixing, a polymer having any one of a softening point, a glass transition point, and a melting point within a range of 40 ° C. to 120 ° C. is preferable.
In the present invention, the polymer particularly preferably used as the coating agent is a polymer containing at least one of the structural units represented by the following general formulas (1) to (4).

In the formula, X ¹¹ represents an oxygen atom or —N (R ¹³ ) —. R ¹¹ represents a hydrogen atom or a methyl group, R ¹² represents a hydrocarbon group having 1 to 30 carbon atoms, and R ¹³ represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms. R ²¹ represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms. R ³¹ , R ³² and R ⁴¹ each represent a divalent hydrocarbon group having 1 to 20 carbon atoms. The hydrocarbon group of R ¹² , R ²¹ , R ³¹ , R ³² , and R ⁴¹ may contain an ether bond, an amino group, a hydroxy group, or a halogen substituent.

  The polymer containing the structural unit represented by the general formula (1) can be obtained by radical polymerization of a corresponding radical polymerizable monomer by a known method. Examples of the radical polymerizable monomer used include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, and (meth) acrylic. Octyl acid, 2-ethylhexyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, phenyl (meth) acrylate, benzyl (meth) acrylate, (meth) (Meth) acrylic acid esters such as 2-hydroxyethyl acrylate, N-methyl (meth) acrylamide, N-propyl (meth) acrylamide, N-phenyl (meth) acrylamide, N, N-dimethyl (meth) Examples include (meth) acrylamides such as acrylamide.

The polymer containing the structural unit represented by the general formula (2) can be obtained by radical polymerization of a corresponding radical polymerizable monomer by a known method. Examples of the radical polymerizable monomer used include ethylene, propylene, butadiene, styrene, and 4-methylstyrene.
The polymer containing the structural unit represented by the general formula (3) can be obtained by dehydrating condensation of a corresponding dicarboxylic acid or acid anhydride and a diol by a known method. Examples of the dicarboxylic acid used include succinic anhydride, adipic acid, sebacic acid, isophthalic acid, terephthalic acid, 1,4-phenylenediacetic acid, diglycolic acid and the like. Examples of the diol used include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 1,10-decanediol, and 2-butene- Examples include 1,4-diol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 1,4-benzenedimethanol, and diethylene glycol.

The polymer containing the structural unit represented by the general formula (4) is prepared by dehydrating condensation of a carboxylic acid having a corresponding hydroxy group by a known method or a known cyclic ester of a carboxylic acid having a corresponding hydroxy group. It is obtained by ring-opening polymerization by a method. Examples of the carboxylic acid having a hydroxy group or a cyclic ester thereof include 6-hydroxyhexanoic acid, 11-hydroxyundecanoic acid, hydroxybenzoic acid, and ε-caprolactone.
The polymer containing at least one of the structural units represented by the general formulas (1) to (4) may be a homopolymer of the structural units represented by the general formulas (1) to (4). It may be a copolymer (copolymer) with these constituent components. Moreover, these polymers may be used alone as a lipophilic substance, or may be used in combination of two or more.
Among these, it is preferable to use a copolymer of structural units represented by (1) and (2).

  In addition, the amount of the lipophilic substance contained in the ink composition is preferably in the range of 0.1 to 30% by mass, more preferably in the range of 1 to 20% by mass in terms of solid content.

(Components soluble in dispersion medium)
In the ink composition containing the second specific particles, in order to disperse each component in a fine particle state in a dispersion medium and produce a stable dispersion, it is preferable to contain a dispersant that is soluble in the dispersion medium.
Examples of such a dispersant include surfactants represented by sorbitan fatty acid esters such as sorbitan monooleate and polyethylene glycol fatty acid esters such as polyoxyethylene distearate. Further, for example, a copolymer of styrene and maleic acid, and an amine-modified product thereof, a copolymer of styrene and a (meth) acrylic compound, a (meth) acrylic polymer, a copolymer of polyethylene and a (meth) acrylic compound, rosin, BYK-160, 162, 164, 182 (polyurethane polymer manufactured by Big Chemie), EFKA-401, 402 (acrylic polymer manufactured by EFKA), Solsperse 17000, 24000 (polyester polymer manufactured by Geneca), and the like. In the present invention, from the viewpoint of long-term storage stability of the ink composition, the mass average molecular weight is in the range of 1,000 to 1,000,000 and the polydispersity (mass average molecular weight / number average molecular weight) is Polymers that are in the range of 1.0 to 7.0 are preferred. Furthermore, it is most preferable to use a graft polymer or a block polymer.

  The polymer used particularly preferably in the present invention comprises a polymer component composed of at least one of structural units represented by the following general formulas (5) and (6), and a structural unit represented by the following general formula (7). A graft polymer containing at least a polymer component contained as a graft chain.

In the formula, X ⁵¹ represents an oxygen atom or —N (R ⁵³ ) —. R ⁵¹ represents a hydrogen atom or a methyl group, R ⁵² represents a hydrocarbon group having 1 to 10 carbon atoms, and R ⁵³ represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. R ⁶¹ represents a hydrogen atom, a hydrocarbon group having 1 to 20 carbon atoms, a halogen atom, a hydroxyl group, or an alkoxy group having 1 to 20 carbon atoms. X ⁷¹ represents an oxygen atom or —N (R ⁷³ ) —. R ⁷¹ represents a hydrogen atom or a methyl group, R ⁷² represents a hydrocarbon group having 4 to 30 carbon atoms, and R ⁷³ represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms. The hydrocarbon group of R ⁵² , R ⁶¹ and R ⁷² may contain an ether bond, amino group, hydroxy group or halogen substituent.
The graft polymer is obtained by polymerizing a radical polymerizable monomer corresponding to the general formula (7), preferably in the presence of a chain transfer agent, introducing a polymerizable functional group at the terminal of the obtained polymer, It can be obtained by copolymerizing with a radically polymerizable monomer corresponding to 5) or (6).

Examples of the radical polymerizable monomer corresponding to the general formula (5) include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, and (meth) acrylic acid. Hexyl (meth) acrylate cyclohexyl, phenyl (meth) acrylate, benzyl (meth) acrylate, (meth) acrylic acid esters of 2-hydroxyethyl (meth) acrylate, and N-methyl (meth) acrylamide And (meth) acrylamides such as N-propyl (meth) acrylamide, N-phenyl (meth) acrylamide, and N, N-dimethyl (meth) acrylamide.
Examples of the radical polymerizable monomer corresponding to the general formula (6) include styrene, 4-methylstyrene, chlorostyrene, methoxystyrene, and the like.
Examples of the radical polymerizable monomer corresponding to the general formula (7) include hexyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, dodecyl (meth) acrylate, ( (Meth) stearyl acrylate, and the like.
Specific examples of these graft polymers include polymers represented by the following structural formulas.

  Among them, a polymer component containing at least one of the structural units represented by the general formulas (5) and (6) and a polymerization component containing at least the structural unit represented by the general formula (7) as a graft chain. The graft polymer containing these is preferable.

By adding a dispersant, clogging in the head and ink cartridge due to the presence of particle aggregates can be suppressed, and the image on the printed circuit board has high image quality due to stabilization of each component fine particle. That is obtained and preferred. However, it has been found that if the content of the dispersant is too large, the physical properties of the ink liquid are affected, and the printed dot image tends to diffuse.
Therefore, the mass ratio of (colorant + lipophilic substance) / soluble component is required to be 1 / 0.1 to 1/1 in the present invention, and preferably 1 / 0.2 to The range is 1 / 0.8.

  The method for producing an ink composition containing the second specific particles includes a step of sequentially melting and kneading a colorant and a lipophilic substance, a step of pulverizing the melt-kneaded material, and a pulverized colorant and a lipophilic substance. It includes a step of wet-dispersing the contained particles in a dispersion medium.

(Step of sequentially melting and kneading the colorant and the lipophilic substance)
In the present invention, first, a colorant and a lipophilic substance (polymer) are pulverized, mixed, heated and melted, and kneaded until uniform to prepare a polymer kneaded product uniformly coated with the colorant.
Other methods for uniformly coating the colorant with the polymer include a chemical method using an in-situ polymerization method, a method using a phase separation method (coacervation), and the like.
As an in-situ polymerization method, a colorant and a polymer system are dispersed and then suspension polymerization is performed. In the presence of a dispersant, a colorant is dispersed in an aqueous system to form a polar polymer, a vinyl polymer, or a polyfunctional crosslinking polymer. In addition, there are a polymerization method, a method in which a monomer in which a colorant is dispersed is bulk polymerized, and then suspension polymerization or emulsion polymerization is performed to sufficiently adsorb the colorant.
As the phase separation method (coacervation), after dispersing the colorant in the polymer solution, the solubility of the polymer is lowered by some method to precipitate the polymer from the solution system onto the colorant (in- Compared with the in situ polymerization method, a wide range of polymers can be selected. Add a non-solvent to the resin solution in which the colorant is dispersed to deposit the resin on the surface of the colorant, or finely disperse the colorant in the water-soluble polymer or water-soluble resin solution, and then adjust the pH to color them The method of depositing on the surface of the agent is widely used including rosin treatment. After dispersing the pigment in an acid solution of an acid-soluble nitrogen-containing acrylic resin, increasing the pH and insolubilizing the polymer on the surface of the colorant will prevent aggregation in paints and printing inks, improve fluidity, gloss, and coloring power. The effect is seen.

However, in-situ polymerization method or phase separation method (coacervation) makes it difficult to uniformly disperse the colorant particles in the polymer when the amount of the colorant is reduced with respect to the polymer. On the other hand, the heat-melt kneading method of the present method can uniformly disperse the colorant particles in the polymer regardless of the ratio of the polymer and the colorant particles. Specifically, after mixing the colorant and the polymer in advance, the mixture is kneaded with a kneader, three rolls, a Banbury mixer or the like while being heated. A water-containing paste (wet cake) of a colorant was kneaded with a polymer or a polymer and a solvent in advance, water was replaced with the polymer or polymer solution, and then the water and the solvent were dried under reduced pressure to obtain a colored mixture (flushing treatment) It is also possible to heat-knead and knead afterwards.
The heating temperature is selected depending on the polymer used, but is generally in the range of 50 ° C to 200 ° C. The kneading time is preferably in the range of 30 minutes to 6 hours from the viewpoint of uniform mixing of the colorant and the polymer.

(Process of crushing melt-kneaded material)
The colored admixture obtained in the above step is pulverized. At this time, from the viewpoint of obtaining a desired uniform fine powder detail, it is preferable to perform two-step pulverization after coarse pulverization and then fine pulverization. As the coarse pulverizer, a roll mill, a cutter mill, a hammer mill or the like is generally used, and the colored admixture is pulverized to about 0.5 to 1 mm by pulverization.
Examples of the fine pulverizer include a high-speed rotation type, a ball mill type, a medium agitation type, and an airflow pulverization type. High-speed rotation types include disc mill type, pin mill type, screw mill type, centrifugal classification mill type, etc., ball mill type includes rolling type, vibration type, and planetary type. There are two types: an airflow suction type, a nozzle suction type, a collision object collision type, and an airflow collision type. Specifically, a jet-O-mizer, a single truck jet mill (FS-4) manufactured by Seishin Co., Ltd., a jet mill manufactured by Fuji Sangyo Co., Ltd., a PJ-manufactured by Nippon Pneumatic Co., Ltd. There are M-type supersonic jet pulverizers, and any pulverizer can be used. The colored mixture is pulverized to about 5 to 300 μm by these pulverizers.

  The finely pulverized colored admixture is preferably further classified. The classification includes sieving classification, dry airflow classification, forced vortex-type dry airflow classification, and a specific example of forced vortex-type dry airflow classifier is a specic classifier (SPC-250) manufactured by Seishin Enterprise Co., Ltd. Yes, it is preferable to classify to 10 to 100 μm with these classifiers. When finely pulverized to this level, uniform particles can be obtained in a short time in the next wet dispersion step. On the other hand, if the pulverization is insufficient and coarse particles are present, the coarse particles remain indefinitely dispersed, resulting in a broad particle size distribution and a long dispersion time.

(Process of wet-dispersing particles containing pulverized colorant and lipophilic substance in a dispersion medium)
This dispersion step is a step of adding and dispersing the fine particles composed of the colorant and the lipophilic substance in the mixed liquid containing the dispersion medium and the dispersant. The above-mentioned dispersion medium and dispersant are used, and the addition amount is also within the preferred range of the present invention.
The disperser used in this dispersion step is not particularly limited, and a commercially available wet disperser can be used. For example, a ball mill, a sand mill, an attritor, etc., and a sealed type is generally used to prevent evaporation of the solvent. Sand mills have a vertical type and a horizontal type, and are dispersed by rotating a shaft on which a disk or a pin is attached at a peripheral speed of 3 to 15 m / s. By arranging several continuous sand mills in series and changing the diameter of the media according to the degree of dispersion, the ink composition can be efficiently produced. Further, when a large particle size is dispersed by a continuous sand mill, pre-dispersion is required. In this case, a disperser, a ball mill, a batch sand mill, or the like is used as a pre-dispersing machine.
Specific examples of the horizontal sand mill include dyno mill, dyno mill ECM (Switzerland, WAB), pearl mill, DCP (Germany, Dreis), agitator mill (Germany, Netsch), super mill (Belgium, Sasmeier), Cobol mill (Switzerland, Freema), spike mill (Inoue Seisakusho), and the like.

Various media such as zirconia, titania, alumina, glass, steel, silicon nitride can be used as media for ball mills and sand mills. In accordance with the viscosity of the dispersion, the degree of pre-dispersion, and the like, the material of the media is selected from the viewpoint of the specific gravity of the media, wear resistance and the like.
The media diameter is not particularly limited, but for example, media having a diameter of about 0.1 mm to 10 mm can be used. In general, the larger the media, the wider the particle size distribution, and the smaller the media, the smaller the particle size tends to be dispersed. Also, the media filling rate is not particularly limited, but a media filling rate of 50% to 90% is preferable. There is a close relationship between the filling rate of media and the dispersion performance, and it is generally known that the dispersion efficiency can be improved if the filling rate can be increased. In the case of a horizontal mill, the media locking phenomenon at the time of start-up does not occur at all as compared with the vertical mill, so that the filling rate is preferably 80 to 85% with respect to the vessel capacity.
Dispersion may be carried out at room temperature or by heating to room temperature to about 60 ° C. The volume average diameter of the colorant-containing polymer particles in the dispersion medium obtained in the dispersion step as described above is 0.2 to 5.0 μm. A more preferable volume average diameter is 0.5 to 5.0 μm.

(Coloring agent)
The ink composition of the present invention can form a visible image by adding a colorant. For example, when forming an image area of a lithographic printing plate, it is not always necessary to add it, but it is also preferable to use a colorant from the viewpoint of plate inspection of the obtained lithographic printing plate.
There is no restriction | limiting in particular in the coloring agent which can be used here, According to a use, well-known various color materials and (pigment, dye) can be selected suitably, and can be used. For example, when forming an image excellent in weather resistance, a pigment is preferable. As the dye, both water-soluble dyes and oil-soluble dyes can be used, but oil-soluble dyes are preferred.

[Pigment]
The pigment preferably used in the present invention will be described.
The pigment is not particularly limited, and all commercially available organic and inorganic pigments or pigments dispersed in an insoluble resin or the like as a dispersion medium, or the resin is grafted onto the pigment surface Can be used. Moreover, what dye | stained the resin particle with dye can be used.
Examples of these pigments include, for example, “Pigment Dictionary” (2000), edited by Seijiro Ito. Herbst, K.M. Hunger “Industrial Organic Pigments”, JP 2002-12607 A, JP 2002-188025 A, JP 2003-26978 A, and JP 2003-342503 A3.

  Specific examples of organic pigments and inorganic pigments that can be used in the present invention include C.I. I. Pigment Yellow 1 (Fast Yellow G etc.), C.I. I. A monoazo pigment such as C.I. Pigment Yellow 74; I. Pigment Yellow 12 (disaji yellow AAA, etc.), C.I. I. Disazo pigments such as C.I. Pigment Yellow 17; I. Non-benzidine type azo pigments such as CI Pigment Yellow 180; I. Azo lake pigments such as C.I. Pigment Yellow 100 (eg Tartrazine Yellow Lake); I. Condensed azo pigments such as CI Pigment Yellow 95 (Condensed Azo Yellow GR, etc.); I. Acidic dye lake pigments such as C.I. Pigment Yellow 115 (such as quinoline yellow lake); I. Basic dye lake pigments such as CI Pigment Yellow 18 (Thioflavin Lake, etc.), anthraquinone pigments such as Flavantron Yellow (Y-24), isoindolinone pigments such as Isoindolinone Yellow 3RLT (Y-110), and quinophthalone yellow Quinophthalone pigments such as (Y-138), isoindoline pigments such as isoindoline yellow (Y-139), C.I. I. Nitroso pigments such as C.I. Pigment Yellow 153 (nickel nitroso yellow, etc.); I. And metal complex salt azomethine pigments such as CI Pigment Yellow 117 (copper azomethine yellow, etc.).

  C. As a thing which exhibits red or magenta color, C.I. I. Monoazo pigments such as CI Pigment Red 3 (Toluidine Red, etc.); I. Disazo pigments such as C.I. Pigment Red 38 (Pyrazolone Red B, etc.); I. Pigment Red 53: 1 (Lake Red C, etc.) and C.I. I. Azo lake pigments such as C.I. Pigment Red 57: 1 (Brilliant Carmine 6B); I. Condensed azo pigments such as C.I. Pigment Red 144 (condensed azo red BR, etc.); I. Acidic dye lake pigments such as C.I. Pigment Red 174 (Phloxine B Lake, etc.); I. Basic dye lake pigments such as C.I. Pigment Red 81 (Rhodamine 6G ′ Lake, etc.); I. Anthraquinone pigments such as C.I. Pigment Red 177 (eg, dianthraquinonyl red); I. Thioindigo pigments such as C.I. Pigment Red 88 (Thioindigo Bordeaux, etc.); I. Perinone pigments such as C.I. Pigment Red 194 (perinone red, etc.); I. Perylene pigments such as C.I. Pigment Red 149 (perylene scarlet, etc.); I. Pigment violet 19 (unsubstituted quinacridone), C.I. I. Quinacridone pigments such as CI Pigment Red 122 (quinacridone magenta, etc.); I. Isoindolinone pigments such as CI Pigment Red 180 (isoindolinone red 2BLT, etc.); I. And alizarin lake pigments such as CI Pigment Red 83 (Mada Lake, etc.).

  As a pigment exhibiting blue or cyan, C.I. I. Disazo pigments such as C.I. Pigment Blue 25 (Dianisidine Blue, etc.); I. Phthalocyanine pigments such as C.I. Pigment Blue 15 (phthalocyanine blue, etc.); I. Acidic dye lake pigments such as C.I. Pigment Blue 24 (Peacock Blue Lake, etc.); I. Basic dye lake pigments such as C.I. Pigment Blue 1 (Viclotia Pure Blue BO Lake, etc.); I. Anthraquinone pigments such as C.I. Pigment Blue 60 (Indantron Blue, etc.); I. And alkali blue pigments such as CI Pigment Blue 18 (Alkali Blue V-5: 1).

As a pigment exhibiting green, C.I. I. Pigment green 7 (phthalocyanine green), C.I. I. Phthalocyanine pigments such as C.I. Pigment Green 36 (phthalocyanine green); I. And azo metal complex pigments such as CI Pigment Green 8 (Nitroso Green).
As a pigment exhibiting an orange color, C.I. I. An isoindoline pigment such as C.I. Pigment Orange 66 (isoindoline orange); I. And anthraquinone pigments such as CI Pigment Orange 51 (dichloropyrantron orange).

Examples of the black pigment include carbon black, titanium black, and aniline black.
Specific examples of the white pigment include basic lead carbonate (2PbCO ₃ Pb (OH) ₂ , so-called silver white), zinc oxide (ZnO, so-called zinc white), titanium oxide (TiO ₂ , so-called titanium white), Strontium titanate (SrTiO ₃ , so-called titanium strontium white) or the like can be used.

  Here, titanium oxide has a smaller specific gravity than other white pigments, a large refractive index, and is chemically and physically stable, so that it has a large hiding power and coloring power as a pigment. Excellent durability against other environments. Therefore, it is preferable to use titanium oxide as the white pigment. Of course, other white pigments (may be other than the listed white pigments) may be used as necessary.

For dispersing the pigment, for example, a dispersion device such as a ball mill, a sand mill, an attritor, a roll mill, a jet mill, a homogenizer, a paint shaker, a kneader, an agitator, a Henschel mixer, a colloid mill, an ultrasonic homogenizer, a pearl mill, or a wet jet mill is used. be able to.
It is also possible to add a dispersant when dispersing the pigment. Examples of the dispersant include a hydroxyl group-containing carboxylic acid ester, a salt of a long-chain polyaminoamide and a high molecular weight acid ester, a salt of a high molecular weight polycarboxylic acid, a high molecular weight unsaturated acid ester, a high molecular copolymer, a modified polyacrylate, an aliphatic Examples thereof include polyvalent carboxylic acids, naphthalene sulfonic acid formalin condensates, polyoxyethylene alkyl phosphate esters, and pigment derivatives. It is also preferable to use a commercially available polymer dispersant such as the Solsperse series from Zeneca.
Moreover, it is also possible to use a synergist according to various pigments as a dispersion aid. These dispersants and dispersion aids are preferably added in an amount of 1 to 50 parts by mass with respect to 100 parts by mass of the pigment.

The average particle size of the pigment is preferably 0.02 to 4 μm, more preferably 0.02 to 2 μm, and more preferably 0.02 to 1.0 μm.
Selection of pigments, dispersants, and dispersion media, dispersion conditions, and filtration conditions are set so that the average particle diameter of the pigment particles falls within the above preferred range. By controlling the particle size, clogging of the head nozzle can be suppressed, and ink storage stability, ink transparency, and curing sensitivity can be maintained.

〔dye〕
The dye used in the present invention is preferably oil-soluble. Specifically, it means that the solubility in water at 25 ° C. (the mass of the dye dissolved in 100 g of water) is 1 g or less, preferably 0.5 g or less, more preferably 0.1 g or less. Accordingly, so-called water-insoluble oil-soluble dyes are preferably used.

The dye used in the present invention preferably has an oil-solubilizing group introduced into the above-described dye mother core in order to dissolve the necessary amount in the ink composition.
As the oil-solubilizing group, long chain, branched alkyl group, long chain, branched alkoxy group, long chain, branched alkylthio group, long chain, branched alkylsulfonyl group, long chain, branched acyloxy group, long chain, branched alkoxycarbonyl group, Long chain, branched acyl group, long chain, branched acylamino group long chain, branched alkylsulfonylamino group, long chain, branched alkylaminosulfonyl group and these long chains, aryl groups containing branched substituents, aryloxy groups, aryloxycarbonyl Group, arylcarbonyloxy group, arylaminocarbonyl group, arylaminosulfonyl group, arylsulfonylamino group and the like.
In addition, for water-soluble dyes having carboxylic acid and sulfonic acid, long chain, branched alcohol, amine, phenol, aniline derivatives are used as oil-solubilizing alkoxycarbonyl groups, aryloxycarbonyl groups, alkylaminosulfonyl groups, A dye may be obtained by conversion to an arylaminosulfonyl group.

The oil-soluble dye preferably has a melting point of 200 ° C. or lower, more preferably has a melting point of 150 ° C. or lower, and still more preferably has a melting point of 100 ° C. or lower. By using an oil-soluble dye having a low melting point, the precipitation of dye crystals in the ink composition is suppressed, and the storage stability of the ink composition is improved.
Further, it is desirable that the oxidation potential is noble (high) in order to improve fading, particularly resistance to oxidizing substances such as ozone and curing characteristics. For this reason, as the oil-soluble dye used in the present invention, those having an oxidation potential of 1.0 V (vs SCE) or more are preferably used. The oxidation potential is preferably higher, the oxidation potential is more preferably 1.1 V (vs SCE) or more, and particularly preferably 1.15 V (vs SCE) or more.

As the yellow dye, a compound having a structure represented by the general formula (Y-I) described in JP-A No. 2004-250483 is preferable.
Particularly preferred dyes are dyes represented by the general formulas (Y-II) to (Y-IV) described in paragraph [0034] of JP-A No. 2004-250483. And the compounds described in paragraphs [0060] to [0071] of JP-A-250483. The oil-soluble dye of the general formula (Y-I) described in the publication may be used not only for yellow but also for inks of any color such as black ink and red ink.

The magenta dye is preferably a compound having a structure represented by the general formulas (3) and (4) described in JP-A No. 2002-114930. Specific examples include paragraphs of JP-A No. 2002-114930. Examples include the compounds described in [0054] to [0073].
Particularly preferred dyes are azo dyes represented by the general formulas (M-1) to (M-2) described in paragraph numbers [0084] to [0122] of JP-A No. 2002-121414, and specific examples Examples thereof include compounds described in paragraph numbers [0123] to [0132] of JP-A No. 2002-121414. The oil-soluble dyes represented by the general formulas (3), (4) and (M-1) to (M-2) described in the publication are used not only for magenta but also for any color ink such as black ink and red ink. May be.

Examples of cyan dyes include dyes represented by formulas (I) to (IV) described in JP-A No. 2001-181547, and paragraphs [0063] to [0078] of JP-A No. 2002-121414. The dyes represented by the general formulas (IV-1) to (IV-4) are listed as preferable examples, and specific examples include paragraph numbers [0052] to [0066] in JP-A No. 2001-181547. Examples thereof include the compounds described in paragraph Nos. [0079] to [0081] of Kai 2002-121414.
Particularly preferred dyes are phthalocyanine dyes represented by general formulas (CI) and (C-II) described in paragraphs [0133] to [0196] of JP-A No. 2002-121414, A phthalocyanine dye represented by formula (C-II) is preferred. Specific examples thereof include the compounds described in JP-A No. 2002-121414, paragraph numbers [0198] to [0201]. The oil-soluble dyes of the formulas (I) to (IV), (IV-1) to (IV-4), (CI) and (C-II) are not only cyan but also black ink or green ink. The ink may be used for any color ink.

In the present invention, it is more preferable to use a dye as the colorant.
These colorants are preferably added in an amount of 1 to 20% by mass in terms of solid content in the ink composition, and more preferably 2 to 10% by mass.

(C) Charge adjusting agent The ink composition of the present invention preferably controls conductivity from the viewpoint of electrostatic discharge. By controlling the conductivity of the ink, it is possible to prevent interference between adjacent channels and discharge while maintaining a high ejection frequency. When the conductivity is adjusted, the above-described conductive salts for ink, known conductive agents or charge control agents (for example, “Recent development and practical use of electrophotographic development systems and toner materials” 139 to 148 are used. Pp. 497-505 (Corona, 1988), Yuji Harasaki “Electrophotography” 16 (No. 2), 44 (1977), UK Patent No. 893429, U.S. Pat. No. 9,340,38, U.S. Pat. Nos. 3,940,402, 4,606,989, JP-A-60-179751, JP-A-60-185963, JP-A-2-13965, etc.) Can be done.

Specifically, metal salts of organic carboxylic acids such as zirconium naphthenate and zirconium octenoate, ammonium salts of organic carboxylic acids such as tetramethylammonium stearate, sodium dodecylbenzenesulfonate, magnesium dioctylsulfosuccinate In the side chain of a metal salt of an organic sulfonic acid such as a salt, an ammonium salt of an organic sulfonic acid such as a toluene butyl tetrabutylammonium salt, or a polymer containing a carboxylic acid group obtained by modifying a copolymer of styrene and maleic anhydride with an amine. A polymer having a carboxylic acid group, a polymer having a carboxylic acid anion group in a side chain such as a copolymer of stearyl methacrylate and a tetramethylammonium salt of methacrylic acid, a nitrogen atom in a side chain of a copolymer of styrene and vinylpyridine, etc. A polymer having a meta Butyl acrylic acid and N- (2-methacryloyloxyethyl) -N, N, polymers having an ammonium group in the side chain of the copolymer of N- trimethylammonium tosylate salt. The charge imparted to the particles may be positively charged or negatively charged.
Also, a metal soap described in JP-A-11-109681 can be suitably used as a charge adjusting agent.

Furthermore, the charge control agents listed below can also be used.
(1) It contains an alcohol amine formed by bonding a hydroxy group to a carbon atom of an amine molecule.
(2) An amine-containing resin and / or a carboxyl group- or hydroxyl group-containing substance is contained.
(3) General formula R ₁ N + H ₂ · R ₂ COO— (wherein R ₁ represents an alkyl group having 1 to 18 carbon atoms, and R ₂ represents a hydrogen atom or an alkyl group having 1 to 18 carbon atoms) Provided that at least one of R ₁ and R ₂ is an alkyl group having 8 to 18 carbon atoms).
(4) Including polyaminopolybutenyl succinimide.
(5) Contains at least one of the following (C1) to (C6).
(C1) a salt of a triarylmethane compound having an amino group and an acidic compound soluble in a dispersion medium,
(C2) a salt of a dye having an amino group and an acidic compound soluble in the dispersion medium,
(C3) a salt of a dye having an amino group and a fatty acid having 5 or more carbon atoms,
(C4) a nitrogen-containing heterocyclic compound having an amino group,
(C5) a salt of a basic nitrogen atom-containing compound and a polymer carboxylic acid soluble in a dispersion medium,
(C6) A combination of a nitrogen-containing heterocyclic compound having an amino group and an ether compound having a polyoxyethylene group.
(6) Contains a titanium compound having a specific structure.
(7) An ionic or zwitterionic charge control compound soluble in a nonpolar liquid and a β-diketone metal salt are contained.
(8) A mixture containing the following component (A) and component (B) and having a mass ratio of the following component (B): component (A) from 10: 3 to 40: 3.
(A) (i) a chromium salt of C14-18 alkylsalicylic acid; (ii) calcium didecylsulfosuccinate; and (iii) a copolymer of lauryl methacrylate, stearyl methacrylate and 2-methyl-5-vinylpyridine, the copolymer being 20 Each having a vinylpyridine content of ˜30% by weight and an average molecular weight of 15,000 to 250,000, wherein at least 50% of the basic nitrogen groups are salts of sulfosuccinic acid didecyl ester; A salt mixture composed of 10 parts by weight;
(B) a salt-free copolymer of (i) lauryl methacrylate and (ii) a monomer selected from the group consisting of 2- or 4-vinylpyridine, styrene and N, N-dimethylaminoethyl methacrylate, A copolymer having a molecular weight of 15,000 to 100,000 and a weight ratio of said monomer B (i) to B (ii) of 4: 1 to 50: 1.
(9) Including the following copolymer particles.
Copolymer particles: thermoplastic resin core substantially insoluble in the dispersion medium, chemically fixed to the core, soluble in the dispersion medium, and having a pKa of less than 4.5 A copolymer steric stabilizer having a chemically bonded moiety containing an organic acid, wherein the organic acid is chemically a metal soap compound derived from an organic acid having a pKa of greater than 4.5 Combined.
(10) A charge generator composition obtained by mixing a charge generator, a solvent, and a polar monomer species and causing a polymerization reaction is included.
(11) Contains a hydroxybenzoate compound.
(12) (A) a thermoplastic resin-like core insoluble or substantially insoluble in the dispersion medium, (B) chemically fixed to the core, soluble in the dispersion medium, and coordinated A copolymer steric stabilizer having a covalent compound moiety as a cohesive compound, and (C) at least one metal soap compound derived from a metal that forms a coordination bond with the coordination compound moiety. Contains copolymer particles.
(13) While containing a metal salt, the charged particles have an ion exchange site that forms a complex with the metal salt.
(14) It contains a steric stabilizer and a charge generation component, and the charge generation component contains a coordination association in which a monovalent alkali metal cation or an ammonium cation is bonded.
(15) Including an alkyl phosphate having a specific structure.
(16) It contains a phosphate ester of glycerin having a specific structure.
(17) An organic compound containing any one of 2 to 4 valent metals is contained.
(18) An amino group-containing organopolysiloxane having a viscosity at 25 ° C. of 30 centipoise or less is contained.
(19) Includes a charge director and cyclodextrin or a derivative thereof.
(20) An isocyanurate compound having a tertiary amino group at a molecular end and a polymer chain excellent in affinity with the coating polymer is included.
(21) A metal salt of octylic acid and / or a metal salt of naphthenic acid and a phosphate ester-based surfactant.
(22) An organometallic compound containing aluminum is included.

  The content of the charge adjusting agent with respect to the entire ink composition is preferably in the range of 0.0001 to 10% by mass. More preferably, it is 0.001-5 mass%.

(D) Polymerization initiator As the polymerization initiator (D) in the present invention, known compounds can be used as a thermal polymerization initiator and a photopolymerization initiator. For example, a radical polymerization initiator and a cationic polymerization initiator are mentioned. (D) The polymerization initiator is not particularly limited as long as it can be dissolved in (A) a dispersion medium, but (B) a process for heat-sealing resin particles to a lithographic printing plate is required, and the heat can be used. Preferred thermal polymerization initiators are preferred. (D) The addition amount of a polymerization initiator is 0.01-20 mass% with respect to the following (E) polymeric compound, More preferably, it is 0.5-10 mass%. Hereinafter, preferred (D) polymerization initiators are exemplified.

  Examples of the polymerization initiator that can be used in the present invention include a photoinitiator for photocationic polymerization, a photoinitiator for radical photopolymerization, a photodecolorant for dyes, a photochromic agent, or light used for a microresist ( 400-200 nm ultraviolet rays, far ultraviolet rays, particularly preferably g-line, h-line, i-line, KrF excimer laser beam), ArF excimer laser beam, electron beam, X-ray, molecular beam, ion beam, etc. The generated compound can be appropriately selected and used.

  As such a photopolymerization initiator, for example, an onium salt such as a diazonium salt, an ammonium salt, a phosphonium salt, an iodonium salt, a sulfonium salt, a selenonium salt, an arsonium salt, which generates an acid upon decomposition by irradiation with active energy, Organic halogen compounds, organic metal / organic halides, photoacid generators having an o-nitrobenzyl-type protecting group, compounds that generate sulfonic acids by photolysis, such as iminosulfonates, disulfone compounds, diazoketo A sulfone and a diazo disulfone compound can be mentioned.

  Further, oxazole derivatives and s-triazine derivatives described in JP-A No. 2002-122994, paragraph numbers [0029] to [0030] are also preferably used. Furthermore, onium salt compounds and sulfonate compounds exemplified in JP-A No. 2002-122994, paragraph numbers [0037] to [0063] can also be suitably used as the component (D-1) in the present invention.

  Furthermore, there is a photopolymerization initiator that generates a chemical change through the action of light or interaction with the electronically excited state of a sensitizing dye to generate at least one of a radical, an acid, and a base.

  For example, (a) aromatic ketones, (b) aromatic onium salt compounds, (c) organic peroxides, (d) hexaarylbiimidazole compounds, (e) ketoxime ester compounds, (f) borate compounds, (G) Azinium compounds, (h) metallocene compounds, (i) active ester compounds, (j) compounds having a carbon halogen bond, and the like.

[Sensitizing dye]
In the present invention, a sensitizing dye may be added for the purpose of improving the sensitivity of the photopolymerization initiator. Examples of preferred sensitizing dyes include those belonging to the following compounds and having an absorption wavelength in the 350 nm to 450 nm region.
Polynuclear aromatics (eg, pyrene, perylene, triphenylene), xanthenes (eg, fluorescein, eosin, erythrosine, rhodamine B, rose bengal), cyanines (eg, thiacarbocyanine, oxacarbocyanine), merocyanines ( For example, merocyanine, carbomerocyanine), thiazines (eg, thionine, methylene blue, toluidine blue), acridines (eg, acridine orange, chloroflavin, acriflavine), anthraquinones (eg, anthraquinone), squalium (eg, squalium) ), Coumarins (eg 7-diethylamino-4-methylcoumarin).

[Co-sensitizer]
Further, a known compound having an effect of further improving sensitivity or suppressing polymerization inhibition by oxygen may be added as a co-sensitizer.

  Examples of such co-sensitizers include amines such as MR Sander et al., “Journal of Polymer Society”, Vol. 10, page 3173 (1972), Japanese Examined Patent Publication No. 44-20189, Japanese Patent Laid-Open No. 51-82102. Publication, JP 52-134692, JP 59-138205, JP 60-84305, JP 62-18537, JP 64-33104, Research Disclosure 33825 Specifically, triethanolamine, p-dimethylaminobenzoic acid ethyl ester, p-formyldimethylaniline, p-methylthiodimethylaniline and the like can be mentioned.

  Other examples include thiols and sulfides, for example, thiol compounds described in JP-A-53-702, JP-B-55-500806, JP-A-5-142772, and JP-A-56-75643. Specific examples include disulfide compounds, and specific examples include 2-mercaptobenzothiazole, 2-mercaptobenzoxazole, 2-mercaptobenzimidazole, 2-mercapto-4 (3H) -quinazoline, β-mercaptonaphthalene, and the like.

  Other examples include amino acid compounds (eg, N-phenylglycine), organometallic compounds described in Japanese Patent Publication No. 48-42965 (eg, tributyltin acetate), and hydrogen described in Japanese Patent Publication No. 55-34414. Donors, sulfur compounds described in JP-A-6-308727 (eg, trithiane), phosphorus compounds described in JP-A-6-250387 (diethylphosphite, etc.), Si-- described in Japanese Patent Application No. 6-191605 H, Ge-H compound, etc. are mentioned.

(E) Polymerizable compound The (E) polymerizable compound used in the present invention is not particularly limited, and examples thereof include the following cationic polymerizable compounds and radical polymerizable compounds. In particular, (A) a material that can be dissolved in a dispersion medium and that is within the ink physical property range suitable for the ink jet ejection characteristics, can improve the printing durability without deteriorating the head clogging and dot bleeding, and has a low viscosity. Functional monomers are more preferred.
(E) The addition amount of the polymerizable compound is 0.1 to 20% by mass, more preferably 0.5 to 10% by mass with respect to the total amount of the ink composition. When the content is 0.1% by mass or more, the printing durability is improved, and when the content is 20% by mass or less, aggregation and settling of the dispersion stability of the resin particles is prevented and redispersion is facilitated.

  Examples of the cationic polymerizable compound include JP-A-6-9714, JP-A-2001-31892, JP-A-2001-40068, JP-A-2001-55507, JP-A-2001-310938, JP-A-2001-310937, and JP-A-2001-220526. Examples thereof include epoxy compounds, vinyl ether compounds, oxetane compounds and the like.

Examples of the epoxy compound include aromatic epoxides, alicyclic epoxides, and aromatic epoxides.
Aromatic epoxides include di- or polyglycidyl ethers produced by the reaction of polyphenols having at least one aromatic nucleus or their alkylene oxide adducts and epichlorohydrin, such as bisphenol A or its alkylene oxides. Examples thereof include di- or polyglycidyl ethers of adducts, di- or polyglycidyl ethers of hydrogenated bisphenol A or alkylene oxide adducts thereof, and novolak type epoxy resins. Here, examples of the alkylene oxide include ethylene oxide and propylene oxide.

  As the alicyclic epoxide, cyclohexene oxide obtained by epoxidizing a compound having at least one cycloalkane ring such as cyclohexene or cyclopentene ring with a suitable oxidizing agent such as hydrogen peroxide or peracid. Or a cyclopentene oxide containing compound is mentioned preferably.

  Examples of the aliphatic epoxide include dihydric polyglycidyl ethers of aliphatic polyhydric alcohols or alkylene oxide adducts thereof. Typical examples include diglycidyl ether of ethylene glycol, diglycidyl ether of propylene glycol or diglycidyl ether of alkylene glycol such as diglycidyl ether of 1,6-hexanediol, di- or tri- or di- or tri-glycol or adducts thereof. Polyglycidyl ether of polyhydric alcohol such as glycidyl ether, diglycidyl ether of polyethylene glycol or alkylene oxide adduct thereof, diglycidyl ether of polyalkylene glycol represented by diglycidyl ether of polypropylene glycol or alkylene oxide adduct thereof, etc. Can be mentioned. Here, examples of the alkylene oxide include ethylene oxide and propylene oxide.

The epoxy compound may be monofunctional or polyfunctional.
Examples of monofunctional epoxy compounds that can be used in the present invention include, for example, phenyl glycidyl ether, p-tert-butylphenyl glycidyl ether, butyl glycidyl ether, 2-ethylhexyl glycidyl ether, allyl glycidyl ether, 1,2-butylene oxide, 1,3-butadiene monooxide, 1,2-epoxydodecane, epichlorohydrin, 1,2-epoxydecane, styrene oxide, cyclohexene oxide, 3-methacryloyloxymethylcyclohexene oxide, 3-acryloyloxymethylcyclohexene oxide, 3 -Vinylcyclohexene oxide etc. are mentioned.

  Examples of polyfunctional epoxy compounds include, for example, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol S diglycidyl ether, brominated bisphenol A diglycidyl ether, brominated bisphenol F diglycidyl ether, and brominated bisphenol. S diglycidyl ether, epoxy novolac resin, hydrogenated bisphenol A diglycidyl ether, hydrogenated bisphenol F diglycidyl ether, hydrogenated bisphenol S diglycidyl ether, 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxy 2- (3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy) cyclohexane-meta-dioxane, bis (3,4-epoxycyclo) Xylmethyl) adipate, vinylcyclohexene oxide, 4-vinylepoxycyclohexane, bis (3,4-epoxy-6-methylcyclohexylmethyl) adipate, 3,4-epoxy-6-methylcyclohexyl-3 ′, 4′-epoxy-6 '-Methylcyclohexanecarboxylate, methylenebis (3,4-epoxycyclohexane), dicyclopentadiene diepoxide, ethylene glycol di (3,4-epoxycyclohexylmethyl) ether, ethylenebis (3,4-epoxycyclohexanecarboxylate) , Epoxyhexahydrophthalate dioctyl, epoxyhexahydrophthalate di-2-ethylhexyl, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether Glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ethers, 1,1,3-tetradecadiene dioxide, limonene dioxide, 1,2,7,8- Examples include diepoxyoctane and 1,2,5,6-diepoxycyclooctane.

  Among these epoxy compounds, aromatic epoxides and alicyclic epoxides are preferable from the viewpoint of excellent curing speed, and alicyclic epoxides are particularly preferable.

  Examples of the vinyl ether compound include ethylene glycol divinyl ether, diethylene glycol divinyl ether, triethylene glycol divinyl ether, propylene glycol divinyl ether, dipropylene glycol divinyl ether, butanediol divinyl ether, hexanediol divinyl ether, cyclohexanedimethanol divinyl ether, Di- or trivinyl ether compounds such as methylolpropane trivinyl ether, ethyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, octadecyl vinyl ether, cyclohexyl vinyl ether, hydroxybutyl vinyl ether, 2-ethylhexyl vinyl ether, cyclohexane dimethanol monovinyl ether, n-propyl Pills vinyl ether, isopropyl vinyl ether, isopropenyl ether -O- propylene carbonate, dodecyl vinyl ether, diethylene glycol monovinyl ether, and octadecyl vinyl ether.

The vinyl ether compound may be monofunctional or polyfunctional.
Specifically, examples of monofunctional vinyl ethers include, for example, methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, n-butyl vinyl ether, t-butyl vinyl ether, 2-ethylhexyl vinyl ether, n-nonyl vinyl ether, lauryl vinyl ether, cyclohexyl vinyl ether, Cyclohexylmethyl vinyl ether, 4-methylcyclohexyl methyl vinyl ether, benzyl vinyl ether, dicyclopentenyl vinyl ether, 2-dicyclopentenoxyethyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, butoxyethyl vinyl ether, methoxyethoxyethyl vinyl ether, ethoxyethoxyethyl vinyl ether , Methoxypolyethyleneglycol Vinyl ether, tetrahydrofurfuryl vinyl ether, 2-hydroxyethyl vinyl ether, 2-hydroxypropyl vinyl ether, 4-hydroxybutyl vinyl ether, 4-hydroxymethylcyclohexyl methyl vinyl ether, diethylene glycol monovinyl ether, polyethylene glycol vinyl ether, chloroethyl vinyl ether, chlorobutyl vinyl ether, Examples thereof include chloroethoxyethyl vinyl ether, phenylethyl vinyl ether, phenoxypolyethylene glycol vinyl ether and the like.

Examples of polyfunctional vinyl ethers include ethylene glycol divinyl ether, diethylene glycol divinyl ether, polyethylene glycol divinyl ether, propylene glycol divinyl ether, butylene glycol divinyl ether, hexanediol divinyl ether, bisphenol A alkylene oxide divinyl ether, and bisphenol F. Divinyl ethers such as alkylene oxide divinyl ether; trimethylolethane trivinyl ether, trimethylolpropane trivinyl ether, ditrimethylolpropane tetravinyl ether, glycerin trivinyl ether, pentaerythritol tetravinyl ether, dipentaerythritol pentavinyl ether, dipentaerythritol Hexavinyl ether, ethylene oxide-added trimethylolpropane trivinyl ether, propylene oxide-added trimethylolpropane trivinyl ether, ethylene oxide-added ditrimethylolpropane tetravinyl ether, propylene oxide-added ditrimethylolpropane tetravinyl ether, ethylene oxide-added pentaerythritol tetravinyl ether, propylene oxide addition Examples thereof include polyfunctional vinyl ethers such as pentaerythritol tetravinyl ether, ethylene oxide-added dipentaerythritol hexavinyl ether, and propylene oxide-added dipentaerythritol hexavinyl ether.

  As the vinyl ether compound, a di- or trivinyl ether compound is preferable from the viewpoints of curability, adhesion to a recording medium, surface hardness of the formed image, and the like, and a divinyl ether compound is particularly preferable.

The oxetane compound in the present invention refers to a compound having an oxetane ring, and a known oxetane compound can be arbitrarily selected and used as described in JP-A Nos. 2001-220526, 2001-310937, and 2003-341217. .
The compound having an oxetane ring that can be used in the ink composition of the present invention is preferably a compound having 1 to 4 oxetane rings in the structure. By using such a compound, it becomes easy to maintain the viscosity of the ink composition within a good handling range, and obtain high adhesion between the cured ink composition and the recording medium. Can do.

The compound having such an oxetane ring is described in detail in the above-mentioned JP-A No. 2003-341217, paragraph numbers [0021] to [0084], and the compounds described therein can be suitably used in the present invention.
Among the oxetane compounds used in the present invention, it is preferable to use a compound having one oxetane ring from the viewpoint of the viscosity and tackiness of the ink composition.

  In the ink composition of the present invention, these cationic polymerizable compounds may be used alone or in combination of two or more, but from the viewpoint of effectively suppressing shrinkage during ink curing. Is preferably a combination of at least one compound selected from an oxetane compound and an epoxy compound and a vinyl ether compound.

  Examples of the radically polymerizable compound include compounds having an ethylenically unsaturated bond capable of addition polymerization as described below.

  Examples of the compound having an ethylenically unsaturated bond capable of addition polymerization include unsaturated carboxylic acids (for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.) and aliphatic polyhydric alcohol compounds. And amides of the unsaturated carboxylic acid and the aliphatic polyvalent amine compound.

Specific examples of monomers of esters of aliphatic polyhydric alcohol compounds and unsaturated carboxylic acids include acrylic acid esters such as ethylene glycol diacrylate, triethylene glycol diacrylate, 1,3-butanediol diacrylate, and tetramethylene glycol. Diacrylate, propylene glycol diacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, trimethylolpropane tri (acryloyloxypropyl) ether, trimethylolethane triacrylate, hexanediol diacrylate, 1,4-cyclohexanediol di Acrylate, Tetraethylene glycol diacrylate, Pentaerythritol diacrylate, Pentaerythritol triacrylate , Pentaerythritol tetraacrylate, dipentaerythritol diacrylate, dipentaerythritol hexaacrylate, sorbitol triacrylate, sorbitol tetraacrylate, sorbitol pentaacrylate, sorbitol hexaacrylate, tri (acryloyloxyethyl) isocyanurate, polyester acrylate oligomer.

  Methacrylic acid esters include tetramethylene glycol dimethacrylate, triethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, ethylene glycol dimethacrylate, 1,3-butanediol dimethacrylate, Hexanediol dimethacrylate, pentaerythritol dimethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, dipentaerythritol dimethacrylate, dipentaerythritol hexamethacrylate, sorbitol trimethacrylate, sorbitol tetramethacrylate, bis [p- (3-methacryloxy 2-hydroxypro ) Phenyl] dimethyl methane, bis - [p- (acryloxyethoxy) phenyl] dimethylmethane. Itaconic acid esters include ethylene glycol diitaconate, propylene glycol diitaconate, 1,3-butanediol diitaconate, 1,4-butanediol diitaconate, tetramethylene glycol diitaconate, pentaerythritol diitaconate Sorbitol tetritaconate, etc.

  Examples of crotonic acid esters include ethylene glycol dicrotonate, tetramethylene glycol dicrotonate, pentaerythritol dicrotonate, and sorbitol tetradicrotonate. Examples of isocrotonic acid esters include ethylene glycol diisocrotonate, pentaerythritol diisocrotonate, and sorbitol tetraisocrotonate. Examples of maleic acid esters include ethylene glycol dimaleate, triethylene glycol dimaleate, pentaerythritol dimaleate, and sorbitol tetramaleate. Furthermore, the mixture of the above-mentioned ester monomer can also be mention | raise | lifted. Specific examples of amide monomers of aliphatic polyvalent amine compounds and unsaturated carboxylic acids include methylene bis-acrylamide, methylene bis-methacrylamide, 1,6-hexamethylene bis-acrylamide, 1,6-hexa. Examples include methylene bis-methacrylamide, diethylenetriamine trisacrylamide, xylylene bisacrylamide, and xylylene bismethacrylamide.

As another example, a vinyl compound containing a hydroxyl group represented by the following general formula (A) is added to a polyisocyanate compound having two or more isocyanate groups per molecule described in JP-B-48-41708. Examples thereof include vinyl urethane compounds containing two or more polymerizable vinyl groups in one molecule to which a monomer is added. CH ₂ = C (R) COOCH ₂ CH (R ′) OH (A) (where R and R ′ represent H or CH ₃ )
Further, as described in JP-A-51-37193, urethane acrylates, JP-A-48-64183, JP-B-49-43191, JP-B-52-30490, etc. Polyfunctional acrylates and methacrylates such as polyester acrylates and epoxy acrylates obtained by reacting an epoxy resin with (meth) acrylic acid can be used. Furthermore, Journal of Japan Adhesion Association vol.20, No. 7, pages 300 to 308 (1984) as photocurable monomers and oligomers can also be used. In the present invention, these monomers may be used in a chemical form such as a prepolymer, that is, a dimer, a trimer and an oligomer, or a mixture thereof and a copolymer thereof.

[Other ingredients]
The various additives used as necessary are described below.
[Ultraviolet absorber]
In the present invention, an ultraviolet absorber can be used from the viewpoint of improving the weather resistance of the obtained image and preventing discoloration.
Examples of the ultraviolet absorber are described in JP-A-58-185679, JP-A-61-190537, JP-A-2-782, JP-A-5-97075, JP-A-9-34057, and the like. Benzotriazole compounds, benzophenone compounds described in JP-A No. 46-2784, JP-A No. 5-194843, US Pat. No. 3,214,463, etc., JP-B Nos. 48-30492 and 56-21141 Cinnamic acid compounds described in JP-A-10-88106, JP-A-4-298503, JP-A-8-53427, JP-A-8-239368, JP-A-10-182621, JP The triazine compounds described in JP-A-8-501291, Research Disclosure No. Examples thereof include compounds described in No. 24239, compounds that emit ultraviolet light by absorbing ultraviolet rays typified by stilbene and benzoxazole compounds, so-called fluorescent brighteners, and the like.
Although the addition amount is appropriately selected according to the purpose, it is generally about 0.5 to 15% by mass in terms of solid content.

[Sensitizer]
If necessary, a sensitizer may be added to the ink composition of the present invention for the purpose of improving the acid generation efficiency of the photoacid generator and increasing the photosensitive wavelength. Any sensitizer may be used as long as the photoacid generator is sensitized by an electron transfer mechanism or an energy transfer mechanism. Preferably, aromatic polycondensed compounds such as anthracene, 9,10-dialkoxyanthracene, pyrene and perylene, aromatic ketone compounds such as acetophenone, benzophenone, thioxanthone and Michlerketone, and heterocyclic compounds such as phenothiazine and N-aryloxazolidinone Is mentioned. The addition amount is appropriately selected according to the purpose, but is generally 0.01 to 1 mol%, preferably 0.1 to 0.5 mol%, based on the photoacid generator.

〔Antioxidant〕
An antioxidant can be added to improve the stability of the ink composition. Examples of the antioxidant include European published patents, 223739, 309401, 309402, 310551, 310552, 359416, and 3435443. JP, 54-85535, 62-262417, 63-113536, 63-163351, JP-A-2-262654, JP-A-2-71262, Examples thereof include those described in Kaihei 3-121449, JP-A-5-61166, JP-A-5-119449, US Pat. No. 4,814,262, US Pat. No. 4,980,275, and the like.
The addition amount is appropriately selected according to the purpose, but is generally about 0.1 to 8% by mass in terms of solid content.

[Anti-fading agent]
In the ink composition of the present invention, various organic and metal complex anti-fading agents can be used. Examples of the organic anti-fading agent include hydroquinones, alkoxyphenols, dialkoxyphenols, phenols, anilines, amines, indanes, chromans, alkoxyanilines, and heterocycles. Examples of the metal complex anti-fading agent include nickel complexes and zinc complexes. No. 17643, VII, I to J, No. 15162, ibid. No. 18716, page 650, left column, ibid. No. 36544, page 527, ibid. No. 307105, page 872, ibid. The compounds described in the patent cited in No. 15162 and the compounds included in the general formulas and compound examples of representative compounds described in JP-A-62-215272, pages 127 to 137 can be used. .
The addition amount is appropriately selected according to the purpose, but is generally about 0.1 to 8% by mass in terms of solid content.

[Conductive salts]
Conductive salts such as potassium thiocyanate, lithium nitrate, ammonium thiocyanate, and dimethylamine hydrochloride can be added to the ink composition of the present invention for the purpose of controlling ejection properties.

〔solvent〕
In order to improve the adhesion to the support, it is also effective to add a very small amount of an organic solvent to the ink composition of the present invention.
Examples of the solvent include ketone solvents such as acetone, methyl ethyl ketone, and diethyl ketone, alcohol solvents such as methanol, ethanol, 2-propanol, 1-propanol, 1-butanol, and tert-butanol, and chlorine such as chloroform and methylene chloride. Solvents, aromatic solvents such as benzene and toluene, ester solvents such as ethyl acetate, butyl acetate and isopropyl acetate, ether solvents such as diethyl ether, tetrahydrofuran and dioxane, glycols such as ethylene glycol monomethyl ether and ethylene glycol dimethyl ether And ether solvents.
In this case, it is effective to add the solvent within a range that does not cause the problem of solvent resistance and VOC, and the amount is preferably 0.1 to 5% by mass, more preferably 0.1 to 3% by mass with respect to the whole ink composition. % Range.

[Surfactant]
A surfactant may be added to the ink composition of the present invention.
Examples of the surfactant include those described in JP-A Nos. 62-173463 and 62-183457. For example, anionic surfactants such as dialkylsulfosuccinates, alkylnaphthalenesulfonates, fatty acid salts, polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, acetylene glycols, polyoxyethylene / polyoxypropylene blocks Nonionic surfactants such as copolymers, and cationic surfactants such as alkylamine salts and quaternary ammonium salts. An organic fluoro compound may be used in place of the surfactant. The organic fluoro compound is preferably hydrophobic. Examples of the organic fluoro compounds include fluorine surfactants, oily fluorine compounds (eg, fluorine oil) and solid fluorine compound resins (eg, tetrafluoroethylene resin). No. (columns 8 to 17) and those described in JP-A Nos. 62-135826.

In addition, for example, a leveling additive, a matting agent, waxes for adjusting film physical properties, a tackifier that does not inhibit polymerization, and the like can be contained as necessary.
As a tackifier, specifically, a high molecular weight adhesive polymer (for example, (meth) acrylic acid and an alkyl group having 1 to 20 carbon atoms) described in JP-A-2001-49200, 5-6p. An ester with an alcohol having, an ester of (meth) acrylic acid and an alicyclic alcohol having 3 to 14 carbon atoms, a copolymer comprising an ester of (meth) acrylic acid and an aromatic alcohol having 6 to 14 carbon atoms) Or a low molecular weight tackifying resin having a polymerizable unsaturated bond.

[Preferred physical properties of ink composition]
The ink composition of the present invention preferably has an ink viscosity of 20 mPa · s or less, more preferably 10 mPa · s or less at the temperature at the time of ejection in consideration of ejection properties. It is preferable to adjust and determine the composition ratio.

  The surface tension of the ink composition of the present invention is preferably 20 to 30 mN / m, more preferably 23 to 28 mN / m. From the viewpoint of bleeding and penetration, 20 mN / m or more is preferable, and the wettability is preferably 30 mN / m or less.

  The conductivity of the ink composition of the present invention is preferably 5 to 1000 nS / m, and preferably 10 to 600 nS / m.

[Inkjet recording apparatus]
The inkjet recording method is preferably an electrostatic method rather than a piezo method.
The ink jet recording method using an electrostatic field concentrates charged particles (color material particles) of an ink composition to an ejection position by electrostatic force by applying a voltage between a control electrode and a back electrode on the back of a recording medium, This is a method of flying from a discharge position to a recording medium. For example, when the charged particles are positive, the voltage applied between the control electrode and the back electrode is such that the control electrode is a positive electrode and the back electrode is a negative electrode.

  As a method of flying ink, for example, there is a method of flying ink from a needle-like tip such as an injection needle, and recording can be performed using the ink composition of the present invention. However, it is difficult to replenish charged particles after the charged particles are concentrated and discharged, and it is difficult to perform stable long-term recording. When the ink is circulated in order to forcibly supply charged particles, the ink overflows from the tip of the injection needle, so the meniscus shape at the tip of the injection needle, which is the discharge position, is not stable, and stable recording is performed. It is difficult to do and is suitable for short-term recording.

  On the other hand, a method of circulating the ink composition without overflowing the ink composition from the ejection opening is preferably used. For example, ink is circulated in an ink chamber having an ejection opening, and a voltage is applied to a control electrode formed at the periphery of the ejection opening, so that it exists in the ejection opening and the leading end faces the recording medium side. In the method in which the concentrated ink droplets fly from the tip of the ink guide, the replenishment of charged particles by the circulation of the ink and the meniscus stability at the ejection position can be compatible, so that stable recording can be performed for a long time. it can. Further, in this method, since the portion where the ink is in contact with the outside air is very small with only the discharge opening, the evaporation of the solvent is suppressed and the ink physical properties are stabilized, so that it can be suitably used in the present invention.

  A configuration example of an ink jet recording apparatus suitable for applying the ink composition of the present invention is shown below. FIG. 1 is an overall configuration diagram schematically showing an example of an ink jet printing apparatus used in the present invention, and an outline of an apparatus that performs single-sided four-color printing on a recording medium P will be described.

  An ink jet recording apparatus 1 shown in FIG. 1 supplies ink to an ejection head 2 composed of ejection heads 2C, 2M, 2Y and 2K for four colors for forming a full-color image, and further the ink from the ejection head 2 A head driver 4 for driving the ejection head 2 by an output from an external device such as a computer (not shown) or a RIP, and a position control means 5. Further, the ink jet recording apparatus 1 includes a transport belt 7 stretched around three rollers 6A, 6B, and 6C, a transport belt position detection unit 8 including an optical sensor that can detect the position of the transport belt 7 in the width direction, An electrostatic attraction unit 9 for holding the recording medium P on the conveyance belt, a static elimination unit 10 and a mechanical unit 11 for peeling the recording medium P from the conveyance belt 7 after completion of image formation are provided. Upstream and downstream of the conveyance belt 7, the feed roller 12 and the guide 13 that supply the recording medium P from the stocker (not shown) to the conveyance belt 7, the ink is fixed to the recording medium P after peeling, and the paper discharge stocker (not shown). An image fixing unit 14 and a guide 15 are arranged to be conveyed. Further, the inkjet printing apparatus 1 has a recording medium P position detecting means 16 at a position facing the ejection head 2 with the conveying belt 7 interposed therebetween, and further recovers the solvent vapor generated from the ink composition. A solvent recovery unit comprising a discharge fan 17 and a solvent vapor adsorbent 18 is disposed, and the vapor inside the apparatus is discharged outside the apparatus through the recovery unit.

  A known roller can be used as the feed roller 12, and the feed roller 12 is arranged so as to increase the feed ability to the recording medium P. The recording medium P supplied by the feed roller is transported to the transport belt 7 through the guide 13. The back surface (preferably metal back surface) of the conveyor belt 7 is installed via a roller 6A. The transported recording medium P is electrostatically attracted onto the transport belt by the electrostatic attracting means 9.

  In FIG. 1, electrostatic adsorption is performed by a scorotron charger connected to a negative high voltage power source. The recording medium P is electrostatically adsorbed without floating on the transport belt 7 by the electrostatic attraction means 9 and the surface of the recording medium is uniformly charged. Here, the electrostatic attraction means is used as the charging means for the recording medium P, but it may be provided separately. The charged recording medium P is transported to the ejection head portion by the transport belt 7, and electrostatic ink jet image formation is performed by superimposing the recording signal voltage with the charging potential as a bias.

  The recording medium P on which the image is formed is neutralized by the neutralizing unit 10, peeled off by the conveying unit 7 by the mechanical unit 11, and conveyed to the fixing unit. The peeled recording medium P is sent to the image fixing means 14 and fixed. The fixed recording medium P is discharged through a guide 15 to a discharge stocker (not shown). Further, the apparatus has a recovery means for solvent vapor generated from the ink composition. The recovery means is composed of the solvent vapor absorbing material 18, and a gas containing solvent vapor in the apparatus is introduced into the adsorbent by the exhaust fan 17, and after the vapor is adsorbed and recovered, it is exhausted outside the apparatus. The apparatus is not limited to the above example, and the number, shape, relative arrangement, charging polarity, and the like of constituent devices such as rollers and chargers can be arbitrarily selected. In the above system, four-color drawing is described. However, a multicolor system may be combined with light color ink or special color ink.

An ink jet recording apparatus used in the above ink jet printing method includes an ejection head 2 and an ink circulation system 3. The ink circulation system 3 further includes an ink tank, an ink circulation device, an ink concentration control device, an ink temperature management device, and the like. In addition, the ink tank may include a stirring device.
As the ejection head 2, a single channel head, a multi-channel head, or a full line head can be used, and main scanning is performed by the rotation of the transport belt 7.

  An ink jet head suitably used in the present invention is an ink jet method in which charged particles in an ink flow path are electrophoresed to increase the ink concentration in the vicinity of an opening and discharge is performed. Ink droplets are ejected by electrostatic attraction caused by the counter electrode disposed on the back surface of the medium. Therefore, if the recording medium or the counter electrode does not face the head, or if no voltage is applied to the recording medium or the counter electrode even at the position facing the head, the voltage is accidentally applied to the ejection electrode. Even when applied or when vibration is applied, ink droplets are not ejected and the interior of the apparatus is not soiled.

  An ejection head preferably used in the ink jet apparatus is shown in FIGS. FIG. 2 is a perspective view showing the configuration of the ink jet head of the ink jet recording apparatus of the present invention (for the sake of clarity, the edge of the guard electrode at each discharge portion is not drawn). FIG. 3 is a side cross-sectional view showing the distribution state of charged particles when the number of ejection units of the ink jet head shown in FIG. 2 is large (corresponding to arrow XX in FIG. 2).

As shown in FIGS. 2 and 3, the inkjet head 70 includes an electrically insulating substrate 74 that constitutes the upper wall of the ink flow path 72 where the ink flow Q in one direction is formed, and the ink to the recording medium P. And a plurality of discharge portions 76 that discharge toward the surface. Each of the ejection portions 76 is provided with an ink guide portion 78 that guides the ink droplet G flying from the ink flow path 72 toward the recording medium P, and the substrate 74 has an opening through which the ink guide portion 78 is inserted. 75 is formed, and the ink meniscus 42 is formed between the ink guide portion 78 and the inner wall surface of the opening 75. The gap d between the ink guide portion 78 and the recording medium P is preferably about 200 μm to 1000 μm. The ink guide portion 78 is fixed to the support rod portion 40 on the lower end side.

  The substrate 74 includes an insulating layer 44 that electrically isolates two discharge electrodes at a predetermined interval, a first discharge electrode 46 formed above the insulating layer 44, and an insulation that covers the first discharge electrode 46. It has a layer 48, a guard electrode 50 formed on the insulating layer 48, and an insulating layer 52 that covers the guard electrode 50. The substrate 74 includes a second ejection electrode 56 formed below the insulating layer 44 and an insulating layer 58 that covers the second ejection electrode 56. The guard electrode 50 is provided in order to prevent an electric field from being affected by the voltage applied to the first ejection electrode 46 and the second ejection electrode 56 in the adjacent ejection section.

Further, the ink jet head 70 constitutes the bottom surface of the ink flow path 72, and the ink flow is generated by the induced voltage that is constantly generated by the pulsed discharge voltage applied to the first discharge electrode 46 and the second discharge electrode 56. A floating conductive plate 62 that moves positively charged ink particles (charged particles) R in the path 72 upward (that is, toward the recording medium side) is provided in an electrically floating state. In addition, a coating film 64 that is electrically insulating is formed on the surface of the floating conductive plate 62 to prevent the physical properties and components of the ink from becoming unstable due to charge injection into the ink. The electric resistance of the insulating coating film is preferably 10 ¹² Ω · cm or more, and more preferably 10 ¹³ Ω · cm or more. In addition, the insulating coating film is desirably resistant to corrosion with respect to ink, and this prevents the floating conductive plate 62 from being corroded by ink. Further, the floating conductive plate 62 is covered with the insulating member 66 from below, and the floating conductive plate 62 is completely electrically insulated by such a configuration.
There is one or more floating conductive plates 62 per unit (for example, when there are four heads C, M, Y, and K, the number of floating conductive plates is at least one each, and C and M The floating conductive plate is not shared between the head units.

  As shown in FIG. 3, in order to cause ink to fly from the inkjet head 70 and record on the recording medium P, the ink in the ink flow path 72 is circulated to generate an ink flow Q, and the guard electrode A predetermined voltage (for example, +100 V) is applied to 50. Furthermore, a flying electric field that attracts the positive charged particles R in the ink droplet G that has been guided by the ink guide portion 78 and flew from the opening 75 to the recording medium P is generated by the first ejection electrode 46 and the second ejection electrode. A positive voltage is applied to the first ejection electrode 46, the second ejection electrode 56, and the recording medium P so as to be formed between the recording medium P and the recording medium P (1 kV when the gap d is 500 μm). A potential difference of about ~ 3.0 kV is taken as a guide).

In this state, when a pulse voltage is applied to the first ejection electrode 46 and the second ejection electrode 56 in accordance with the image signal, the ink droplet G having an increased charged particle concentration is ejected from the opening 75 (for example, initial charged particles). When the concentration is 3 to 15%, the charged particle concentration of the ink droplet G is 30% or more).
At that time, the ink droplet G is applied to the first ejection electrode 46 and the second ejection electrode 56 so that the ink droplet G is ejected only when the pulse voltage is applied to both the first ejection electrode 46 and the second ejection electrode 56. Adjust the voltage value.

As described above, when a pulsed positive voltage is applied, the ink droplet G is guided from the opening 75 to the ink guide portion 78 and flies to adhere to the recording medium P, and the floating conductive plate 62 has the first electric potential.
A positive induced voltage is generated by the positive voltage applied to the ejection electrode 46 and the second ejection electrode 56. Even if the voltage applied to the first ejection electrode 46 and the second ejection electrode 56 is pulsed, this induced voltage is a substantially steady voltage. Therefore, the charged particles R that are positively charged in the ink flow path 72 are subjected to the upward movement force by the electric field formed between the floating conductive plate 62 and the guard electrode 50 and the recording medium P. The concentration of charged particles R increases near the substrate 74. As shown in FIG. 3, when the number of ejection units (that is, channels for ejecting ink droplets) to be used is large, the number of charged particles necessary for ejection increases, but the first ejection electrode 46 and the second ejection electrode to be used are used. Since the number of 56 increases, the induced voltage induced in the floating conductive plate 62 increases, and the number of charged particles R moving to the recording medium also increases.
In the above, an example in which the colored particles are positively charged has been described. However, the colored particles may be negatively charged. In that case, all the above-mentioned charging polarities are reversed.

  In the present invention, it is preferable to fix the ink by an appropriate heating means after discharging the ink onto the recording medium. As the heating means to be used, a contact-type heating device such as a heat roller, a heat block, or a belt heating, and a non-contact type heating device such as a dryer, an infrared lamp, a visible light lamp, an ultraviolet lamp, or a hot air oven may be used. it can. These heating devices are preferably continuous with and integrated with the ink jet recording apparatus. The temperature of the recording medium at the time of fixing is preferably in the range of 40 ° C. to 200 ° C. for ease of fixing. The fixing time is preferably in the range of 1 microsecond to 20 seconds.

[Replenishment of ink composition]
In the ink jet recording method using an electrostatic field, charged particles in the ink composition are concentrated and discharged. Accordingly, when the ink composition is discharged for a long time, the charged particles in the ink composition are reduced, and the electrical conductivity of the ink composition is lowered. Further, the ratio between the electric conductivity of the charged particles and the electric conductivity of the ink composition changes. Further, when discharging, charged particles having a larger diameter tend to be discharged preferentially than charged particles having a smaller diameter, so that the average diameter of the charged particles is reduced. Further, since the solid content in the ink composition changes, the viscosity also changes.

  Due to these changes in physical property values, as a result, ejection failure occurs, the optical density of recorded images decreases, and ink bleeding occurs. For this reason, by reducing the amount of charged particles by replenishing the ink composition having a higher concentration (higher solid content concentration) than the ink composition initially charged in the ink tank, the electrical conductivity of the ink composition The ratio between the electric conductivity of the charged particles and the electric conductivity of the ink composition can be kept within a certain range. Further, the average particle diameter and viscosity can be maintained. Further, by maintaining the physical property value of the ink composition within a certain range, the ink discharge is stably and uniformly performed for a long time. The replenishment at this time is preferably performed mechanically or manually, for example, by detecting a physical property value such as the electrical conductivity or optical density of the ink liquid used and calculating the shortage. Further, the amount of the ink composition to be used may be calculated based on the image data, and may be formed mechanically or manually.

  The lithographic printing plate of the present invention comprises a step of discharging the ink composition onto an ink receptor, and applying heat or heat and light to the discharged ink composition to soften and cure the ink composition. Thus, a hydrophobic image of the ink composition is formed on the ink receiver.

The ink receptor of the present invention is obtained by providing an ink receiving layer on a support.
[Support]
The support (support for lithographic printing plate) used in the present invention will be described.
In this invention, it is preferable that surface roughness Ra of a support body is 0.1-10 micrometers.
Note that Ra is an arithmetic average roughness based on JIS B0601-1994. If the surface roughness is small, the adhesion to the polymerized and cured image is low, and the printing durability is low. On the other hand, if the surface roughness is too large, a portion having a low film thickness is generated, so that the printing durability is lowered. The support used in the present invention is not particularly limited as long as it is a dimensionally stable plate having necessary strength and durability. For example, paper, plastic (for example, polyethylene, polypropylene, polystyrene) Etc.) laminated paper, metal plate (eg, aluminum, zinc, copper, etc.), plastic film (eg, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate) Polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.), paper laminated with metal, or vapor-deposited paper, or plastic film.

  Among them, in the present invention, a polyester film or an aluminum plate is preferable, and among them, an aluminum plate that has good dimensional stability and is relatively inexpensive is particularly preferable. A suitable aluminum plate is a pure aluminum plate or an alloy plate containing aluminum as a main component and containing a trace amount of foreign elements, and may be a plastic film on which aluminum is laminated or vapor-deposited. Examples of foreign elements contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, and titanium. The content of foreign elements in the alloy is at most 10% by mass. In the present invention, a surface-treated aluminum support is preferred. Hereinafter, a preferable aluminum support will be described.

[Aluminum support]
Particularly suitable aluminum in the present invention is pure aluminum, but completely pure aluminum is difficult to produce in the refining technique, and may contain slightly different elements.
Thus, the composition of the aluminum plate applied to the present invention is not specified, and an aluminum plate made of a publicly known material can be appropriately used. The thickness of the aluminum plate used in the present invention is about 0.1 mm to 0.6 mm, preferably 0.15 mm to 0.4 mm, and particularly preferably 0.15 mm to 0.3 mm.

Such an aluminum plate may be subjected to a surface treatment such as a roughening treatment or an anodizing treatment as necessary. Hereinafter, such a surface treatment will be briefly described.
Prior to roughening the aluminum plate, a degreasing treatment with, for example, a surfactant, an organic solvent, or an alkaline aqueous solution for removing rolling oil on the surface is performed as desired. The surface roughening treatment of the aluminum plate is performed by various methods. For example, a method of mechanically roughening, a method of electrochemically dissolving and roughening a surface, and a method of selectively dissolving a surface chemically. This is done by the method of As the mechanical method, a known method such as a ball polishing method, a brush polishing method, a blast polishing method, or a buff polishing method can be used. Further, as an electrochemical surface roughening method, there is a method of performing alternating current or direct current in hydrochloric acid or nitric acid electrolyte. Further, as disclosed in JP-A-54-63902, a method in which both are combined can also be used.

<Details of surface treatment for producing aluminum grain shape>
The lithographic printing plate support of the present invention is preferably one in which the above-mentioned surface grain shape is formed on the surface of the aluminum plate by subjecting the aluminum plate described later to surface treatment. The lithographic printing plate support of the present invention is obtained by subjecting an aluminum plate to a surface roughening treatment and an anodizing treatment, but the production process of this support is not particularly limited, and the surface roughening treatment and the anodizing treatment are performed. Various processes other than the above may be included. As a typical method for forming the above-mentioned surface grain shape, an aluminum plate is successively subjected to a mechanical surface roughening treatment, an alkali etching treatment, an acid desmutting treatment, and an electrochemical surface roughening treatment using an electrolytic solution. Method, mechanical roughening treatment on aluminum plate, alkali etching treatment, desmutting treatment with acid and electrochemical roughening treatment using different electrolytes multiple times, alkali etching treatment on aluminum plate with acid A method of sequentially performing desmutting treatment and electrochemical surface roughening treatment using an electrolytic solution, a method of subjecting an aluminum plate to alkali etching treatment, desmutting treatment with acid, and electrochemical surface roughening treatment using different electrolytic solutions multiple times However, the present invention is not limited to these. In these methods, after the electrochemical roughening treatment, an alkali etching treatment and an acid desmutting treatment may be further performed. As described above, the support for a lithographic printing plate of the present invention obtained by these methods has a structure in which irregularities of two or more different periods are superimposed on the surface, and is a planographic printing plate. Excellent stain resistance and printing durability. Hereinafter, each step of the surface treatment will be described in detail.

<Mechanical roughening>
The mechanical roughening treatment is effective as a roughening treatment means because it can form an uneven surface with an average wavelength of 5 to 100 μm at a lower cost than the electrochemical roughening treatment. is there. Examples of the mechanical surface-roughening treatment method include, for example, a wire brush grain method in which the aluminum surface is scratched with a metal wire, a ball grain method in which the aluminum surface is grained with a polishing ball and an abrasive, JP-A-6-135175, and Japanese Patent Publication A brush grain method in which the surface is grained with a nylon brush and an abrasive described in Japanese Patent No. 50-40047 can be used. A transfer method in which the uneven surface is pressed against the aluminum plate can also be used. That is, in addition to the methods described in JP-A-55-74898, JP-A-60-36195, and JP-A-60-20396, transfer is performed several times. The method described in Japanese Patent Application No. -55871 and Japanese Patent Application No. 4-204235 (Japanese Patent Laid-Open No. 6-024168) characterized in that the surface is elastic is also applicable.

  In addition, by using electric discharge machining, shot blasting, laser, plasma etching, etc., a method of repeatedly transferring using a transfer roll etched with fine irregularities, and an uneven surface coated with fine particles on an aluminum plate It is also possible to use a method in which an uneven pattern corresponding to the average diameter of the fine particles is repeatedly transferred to the aluminum plate a plurality of times by contacting the surface and applying a pressure a plurality of times from above. As a method for imparting fine irregularities to the transfer roll, known methods described in JP-A-3-8635, JP-A-3-66404, JP-A-63-65017, etc. may be used. it can. Further, a fine groove may be cut in two directions using a die, a cutting tool, a laser, or the like on the roll surface, and a square unevenness may be formed on the surface. The roll surface may be subjected to a known etching process or the like so that the formed square irregularities are rounded. Further, in order to increase the surface hardness, quenching, hard chrome plating, or the like may be performed. In addition, as the mechanical surface roughening treatment, methods described in JP-A Nos. 61-162351 and 63-104889 can be used. In the present invention, the above-described methods can be used in combination in consideration of productivity and the like. These mechanical surface roughening treatments are preferably performed before the electrochemical surface roughening treatment.

<Electrochemical roughening treatment>
In the electrochemical surface roughening treatment, an electrolytic solution used for the electrochemical surface roughening treatment using a normal alternating current can be used. Among these, a characteristic uneven structure can be formed on the surface by using an electrolytic solution mainly composed of hydrochloric acid or nitric acid. As the electrolytic surface roughening treatment in the present invention, it is preferable to perform the first and second electrolytic treatments with an alternating waveform current in an acidic solution before and after the cathodic electrolytic treatment. By cathodic electrolysis, hydrogen gas is generated on the surface of the aluminum plate and smut is generated, so that the surface state is made uniform, and uniform electrolytic surface roughening is possible during subsequent electrolysis with alternating waveform current. . This electrolytic surface roughening treatment can be performed according to, for example, an electrochemical grain method (electrolytic grain method) described in Japanese Patent Publication No. 48-28123 and British Patent No. 896,563. This electrolytic grain method uses a sinusoidal alternating current, but it may be performed using a special waveform as described in JP-A-52-58602. Further, the waveform described in JP-A-3-79799 can also be used. JP-A-55-158298, JP-A-56-28898, JP-A-52-58602, JP-A-52-152302, JP-A-54-85802, JP-A-60-190392, JP-A-58-120531, JP-A-63-176187, JP-A-1-5889, JP-A-1-280590, JP-A-1-118489, JP-A-1-148592, and JP-A-1-17896. JP-A-1-188315, JP-A-1-1549797, JP-A-2-235794, JP-A-3-260100, JP-A-3-253600, JP-A-4-72079, JP-A-4-72098, The methods described in JP-A-3-267400 and JP-A-1-141094 can also be applied. In addition to the above, it is also possible to perform electrolysis using an alternating current having a special frequency that has been proposed as a method of manufacturing an electrolytic capacitor. For example, it is described in US Pat. Nos. 4,276,129 and 4,676,879.

  Various electrolyzers and power sources have been proposed. U.S. Pat. No. 4,023,637, JP-A-56-123400, JP-A-57-59770, JP-A-53-12738, JP-A-53. -32821, JP-A 53-32822, JP-A 53-32823, JP-A 55-122896, JP-A 55-13284, JP-A 62-127500, JP-A-1-52100 JP-A-1-52098, JP-A-60-67700, JP-A-1-230800, JP-A-3-257199 and the like can be used. Also, JP-A-52-58602, JP-A-52-152302, JP-A-53-12738, JP-A-53-12739, JP-A-53-32821, JP-A-53-32822, JP 53-32833, JP 53-32824, JP 53-32825, JP 54-85802, JP 55-122896, JP 55-13284, JP 48-28123, JP-B-51-7081, JP-A-52-13338, JP-A-52-133840, JP-A-52-133844, JP-A-52-133845, JP-A-53- Nos. 149135 and 54-146234 can be used.

  As an acidic solution which is an electrolytic solution, in addition to nitric acid and hydrochloric acid, U.S. Pat. Nos. 4,671,859, 4,661,219, 4,618,405, 4,600, 482, 4,566,960, 4,566,958, 4,566,959, 4,416,972, 4,374,710, The electrolyte solution described in each specification of 4,336,113 and 4,184,932 can also be used.

(Nitric acid electrolysis)
Pits having an average opening diameter of 0.5 to 5 μm can be formed by electrochemical surface roughening using an electrolytic solution mainly composed of nitric acid. However, when the amount of electricity is relatively large, the electrolytic reaction is concentrated, and honeycomb pits exceeding 5 μm are also generated. To obtain such a grain, the total amount of electricity furnished to anode reaction on the aluminum plate up until the electrolysis reaction is completed is preferably from ^{1~1000C / dm 2, 50~300C / dm} 2 It is more preferable that The current density at this time is preferably ²⁰ to 100 A / dm ² . Further, when a high concentration or high temperature nitric acid electrolytic solution is used, a small wave structure having an average opening diameter of 0.2 μm or less can be formed.

(Hydrochloric acid electrolysis)
Since hydrochloric acid itself has a strong ability to dissolve aluminum, it is possible to form fine irregularities on the surface with only slight electrolysis. These fine irregularities have an average opening diameter of 0.01 to 0.2 μm and are uniformly generated on the entire surface of the aluminum plate. Such grained total amount of electricity furnished to anode reaction on the aluminum plate up until the electrolysis reaction is completed in order to obtain the, is preferably from 1~100C / dm ^2, in 20~70C / dm ² More preferably. The current density at this time is preferably ²⁰ to 50 A / dm ² .

In such an electrochemical surface roughening treatment with an electrolyte mainly composed of hydrochloric acid, a large crater-like swell is simultaneously formed by increasing the total amount of electricity involved in the anode reaction to 400 to 1000 C / dm ^2. In this case, fine irregularities having an average opening diameter of 0.01 to 0.4 μm are formed on the entire surface by superimposing on a crater-like undulation having an average opening diameter of 10 to 30 μm.

<Alkaline etching treatment>
The alkali etching treatment is a treatment for dissolving the surface layer by bringing the aluminum plate into contact with an alkali solution.

  Alkaline etching performed before the electrolytic surface roughening treatment removes rolling oil, dirt, natural oxide film, etc. on the surface of the aluminum plate (rolled aluminum) if mechanical surface roughening treatment is not performed. If the surface of the unevenness generated by the mechanical surface roughening treatment is dissolved, the surface with sharp undulations is smoothed. It is done for the purpose of changing.

If you do not mechanical surface-roughening treatment before the alkali etching treatment, the etching amount is preferably from 0.1 to 10 g / m ^2, and more preferably 1 to 5 g / m ^2. If the etching amount is less than 0.1 g / m ² , rolling oil, dirt, natural oxide film, etc. may remain on the surface, so uniform pits cannot be generated in the subsequent electrolytic surface roughening treatment, resulting in unevenness. May occur. On the other hand, when the etching amount is 1 to 10 g / m ² , the surface rolling oil, dirt, natural oxide film, and the like are sufficiently removed. An etching amount exceeding the above range is economically disadvantageous.

When performing mechanical surface-roughening treatment before the alkali etching treatment, the etching amount is preferably from 3 to 20 g / m ^2, and more preferably 5 to 15 g / m ^2. If the etching amount is less than 3 g / m ² , the unevenness formed by mechanical surface roughening or the like may not be smoothed, and uniform pit formation may not be possible in subsequent electrolytic treatment. In addition, the stain may deteriorate during printing. On the other hand, when the etching amount exceeds 20 g / m ² , the concavo-convex structure may disappear.

The alkali etching treatment performed immediately after the electrolytic surface roughening treatment is performed for the purpose of dissolving the smut generated in the acidic electrolytic solution and dissolving the edge portion of the pit formed by the electrolytic surface roughening treatment. . Since the pits formed by the electrolytic surface roughening treatment are different depending on the type of the electrolytic solution, the optimum etching amount is also different, but the etching amount of the alkali etching treatment performed after the electrolytic surface roughening treatment is 0.1 to 5 g / m. ² is preferred. When a nitric acid electrolyte is used, the etching amount needs to be set larger than when a hydrochloric acid electrolyte is used. When the electrolytic surface roughening treatment is performed a plurality of times, an alkali etching treatment can be performed as necessary after each treatment.

  Examples of the alkali used in the alkaline solution include caustic alkali and alkali metal salts. Specifically, examples of caustic alkali include caustic soda and caustic potash. Examples of alkali metal salts include alkali metal silicates such as sodium silicate, sodium silicate, potassium metasilicate, and potassium silicate; alkali metal carbonates such as sodium carbonate and potassium carbonate; sodium aluminate and alumina. Alkali metal aluminates such as potassium acid; alkali metal aldones such as sodium gluconate and potassium gluconate; dibasic sodium phosphate, dibasic potassium phosphate, tribasic sodium phosphate, tertiary potassium phosphate, etc. An alkali metal hydrogen phosphate is mentioned. Among these, a caustic alkali solution and a solution containing both a caustic alkali and an alkali metal aluminate are preferable from the viewpoint of high etching rate and low cost. In particular, an aqueous solution of caustic soda is preferable.

<Desmut treatment>
After the electrolytic surface roughening treatment or the alkali etching treatment, pickling (desmut treatment) is performed to remove dirt (smut) remaining on the surface. Examples of the acid used include nitric acid, sulfuric acid, phosphoric acid, chromic acid, hydrofluoric acid, and borohydrofluoric acid. The desmut treatment is performed, for example, by bringing the aluminum plate into contact with an acidic solution having a concentration of 0.5 to 30% by mass (containing 0.01 to 5% by mass of aluminum ions) such as hydrochloric acid, nitric acid, and sulfuric acid. . Examples of the method of bringing the aluminum plate into contact with the acidic solution include, for example, a method of passing the aluminum plate through a bath containing the acidic solution, a method of immersing the aluminum plate in a bath containing the acidic solution, and an acidic solution containing aluminum. The method of spraying on the surface of a board is mentioned. In the desmutting treatment, the acidic solution is mainly composed of an aqueous solution mainly composed of nitric acid or an aqueous solution mainly composed of hydrochloric acid discharged in the above-described electrolytic surface-roughening treatment, or sulfuric acid discharged in an anodic oxidation process described later. It is possible to use a waste solution of an aqueous solution. The liquid temperature in the desmut treatment is preferably 25 to 90 ° C. The processing time is preferably 1 to 180 seconds. Aluminum and aluminum alloy components may be dissolved in the acidic solution used for the desmut treatment.

<Anodizing treatment>
The aluminum plate roughened as described above is subjected to an alkali etching treatment and neutralization treatment as necessary, and then subjected to an anodizing treatment if desired in order to enhance the water retention and wear resistance of the surface. As the electrolyte used for the anodizing treatment of the aluminum plate, various electrolytes that form a porous oxide film can be used. In general, sulfuric acid, phosphoric acid, oxalic acid, chromic acid, or a mixed acid thereof is used. The concentration of these electrolytes is appropriately determined depending on the type of electrolyte.

The treatment conditions for anodization vary depending on the electrolyte used, and thus cannot be specified in general. In general, however, the electrolyte concentration is 1 to 80% by mass solution, the liquid temperature is 5 to 70 ° C., and the current density is 5 to 60 A / dm ^2. A voltage of 1 to 100 V and an electrolysis time of 10 seconds to 5 minutes are suitable. If the amount of the anodic oxide film is less than 2.0 g / m ² , the non-image portion of the planographic printing plate is likely to be scratched, and so-called “scratch stain” in which ink adheres to the scratch portion during printing tends to occur.

<Hydrophilic surface and hydrophilization>
As the hydrophilic surface, an anodic oxide film may be used, but it is preferable to further perform a hydrophilic treatment thereon. The hydrophilic surface here means a surface having a contact angle with water of less than 10 °, and a surface with a surface of less than 5 ° is particularly preferable. Moreover, it is preferable that the hydrophilic compound is adsorbed on the anodized film when the hydrophilic treatment is performed.
Examples of the hydrophilization treatment include treatment with potassium fluorozirconate described in US Pat. No. 2,946,638 and phosphomolybdate described in US Pat. No. 3,201,247. Treatment, alkyl titanate treatment described in British Patent 1,108,559, polyacrylic acid treatment described in German Patent 1,091,433, German Patent 1,134, No. 093 and British Patent No. 1,230,447, polyvinylphosphonic acid treatment, Japanese Patent Publication No. 44-6409, phosphonic acid treatment, US Pat. No. 3,307,951 Phytic acid treatment described in the specification of JP, No. 58-16893 and JP-A No. 58-18291 Treatment with a salt of the molecular compound and a divalent metal include immersion treatment in such polyvalent sulfonic acid compound Tamol.

  Further, phosphates described in JP-A No. 62-019494, water-soluble epoxy compounds described in JP-A No. 62-033692, and JP-A No. 62-097892 Phosphate-modified starch, diamine compounds described in JP-A-63-056498, amino acid inorganic or organic acids described in JP-A-63-130391, JP-A-63-145092 Organic phosphonic acids containing carboxy group or hydroxy group, compounds having amino group and phosphonic acid group described in JP-A-63-165183, and JP-A-2-316290 Specific carboxylic acid derivatives, phosphate esters described in JP-A-3-215095, JP-A-3-261592 Compounds having one amino group and one oxygen acid group of phosphorus described in the publication, phosphoric esters described in JP-A-3-215095, and JP-A-5-246171 Aliphatic or aromatic phosphonic acids such as phenylphosphonic acid, compounds containing S atoms such as thiosalicylic acid described in JP-A-1-307745, and phosphorus described in JP-A-4-282737 Examples of the treatment include undercoating using a compound having a group of oxygen acids. Further, coloring with an acid dye described in JP-A-60-64352 can also be performed.

  Moreover, it is preferable to perform the hydrophilic treatment by a method of immersing in an aqueous solution of an alkali metal silicate such as sodium silicate or potassium silicate.

As the Si adhesion amount, 1.0 to 20.0 mg / m ² is desirably adhered. 2.0 to 17.0 mg / m ² is more desirable. When it is 1.0 mg / m ² or more, the stain resistance is good, and when it is 20.0 mg / m ² or less, the printing durability and burning printing durability are good.

<Washing treatment>
It is preferable to perform water washing after the completion of the above-described processes. For washing, pure water, well water, tap water, or the like can be used. A nip device may be used to prevent the processing liquid from being brought into the next process.

<Ink receiving layer>
Next, in the present invention, an ink receiving layer can be provided on the support.
In order to suppress ink bleeding, the ink receiving layer used in the present invention is one or more compounds selected from the group consisting of an organic fluorine compound having a perfluoroalkyl group and a compound having a dimethylsiloxane skeleton (hereinafter appropriately specified). A layer containing a water repellent compound is preferable. When an ink receiving layer containing a specific water-repellent compound is provided, using it together with a hydrophilic resin gives the ink receiving layer removability with dampening water, etc., and as a result effectively suppresses the occurrence of stains in non-image areas. This is preferable because it is possible.

Hereinafter, the specific water repellent compound will be described.
<Organic fluorine compound having perfluoroalkyl group>
A preferred fluorine-based compound that can be used in the present invention is a compound represented by the general formula R _F -Rpol.
In the above general formula, R _F represents a linear or branched perfluoroalkyl group having 3 or more carbon atoms, and Rpol represents a carboxylic acid or a salt thereof, a sulfonic acid or a salt thereof, phosphoric acid or a salt thereof, a phosphonic acid or a salt thereof. A polar group such as a salt, an amino group or a salt thereof, a quaternary ammonium salt, a polyethyleneoxy skeleton, a polypropyleneoxy skeleton, a sulfonamide group, an ether group or a betaine structure is represented. Among these, those having a sulfoxyl group or a salt structure thereof are preferable because they are less likely to interact with silicate and have good removability.
In addition, it is particularly preferable that R _F has a C _n F _{2n + 1} C _m H _2m COO— skeleton from the viewpoint of suppressing ink bleeding, and has two or more C _n F _{2n + 1} C _m H _2m COO— skeletons in one molecule. More preferred. Here, n is an integer of 2 or more, and m is an integer of 1 or more.
Specific examples [(F-1) to (F-19)] of fluorine-based compounds preferably used in the present invention are listed below, but the present invention is not limited thereto.

Moreover, you may use a high molecular fluorine-type compound as a fluorine-type compound which concerns on this invention. In particular, those having a surfactant action and water-soluble are preferred.
Specific examples of the polymeric fluorosurfactant include a copolymer of an acrylate having a fluoroaliphatic group or a methacrylate having a fluoroaliphatic group and a poly (oxyalkylene) acrylate or poly (oxyalkylene) methacrylate. It is done. In the copolymer, the monomer unit of acrylate or methacrylate having a fluoroaliphatic group is preferably 7 to 60% by mass based on the mass of the copolymer, and the molecular weight of the copolymer is 3000 to 100,000. Is appropriate.

  The fluoroaliphatic group may be linear or branched and preferably contains 40% by mass or more of fluorine. Specific examples of the acrylate or methacrylate having the fluoroaliphatic group include N-butylperfluorooctanesulfonamidoethyl acrylate, N-propylperfluorooctanesulfonamidoethyl acrylate, and methylperfluorooctanesulfonamidoethyl acrylate. The molecular weight of the polyoxyalkylene group in the poly (oxyalkylene) acrylate or methacrylate is preferably 200 to 3000. Examples of the oxyalkylene group include oxyethylene, oxypropylene, and oxybutylene groups, preferably oxyethylene and oxypropylene groups. For example, acrylate or methacrylate having 8 to 15 moles of oxyethylene group added is used. Moreover, foamability can be suppressed by adding a dimethylsiloxane group etc. to the terminal of this polyoxyalkylene group as needed.

The fluorosurfactants as described above can be generally obtained on the market, and commercially available products can also be used in the present invention. Two or more fluorosurfactants can be used in combination.
As products sold, Asahi Glass Co., Ltd., Surflon S-111, S-112, S-113, S-121, S-131, S-141, S-145, S-381, S-382 , Dainippon Ink & Chemicals, Inc. MegaFuck F-110, F120, F-142D, F-150, F-171, F177, F781, Sumitomo 3M Fluorad FC-93, FC-95, FC -98, FC-129, FC135, FX-161, FC170C, FC-171, FC176, Bayer Japan K.K. FT-248, FT-448, FT-548, FT-624, FT-718, FT-738 Etc. (above, trade name).

<Polydimethylsiloxane compound>
Other specific water-repellent compounds that can be used in the present invention include compounds having a dimethylsiloxane skeleton, and specifically include the following compounds.
Examples of the polydimethylsiloxane compound include silicon surfactants. In particular, water-soluble ones are preferable for removal. Examples thereof include dimethylsiloxane methyl (polyoxyethylene) copolymer, dimethylsiloxane methyl (polyoxypropylene) copolymer, and dimethylsiloxane methyl (orioxyethylene / polyoxypropylene) copolymer.

<Hydrophilic resin>
One or more compounds selected from these organic fluorine compounds and compounds having a dimethylsiloxane skeleton and a hydrophilic resin can be blended to form an ink receiving layer.
By using in combination with a hydrophilic resin, it is possible to further improve resistance to smearing and suppression of ink bleeding. In this case, the organic fluorine compound is preferably 50 mg / m ² or less, and the hydrophilic resin is preferably 100 mg / m ² or less. By using a hydrophilic resin in combination, the ink repellency becomes more effective.
The hydrophilic resin that can be used in the present invention is not particularly limited as long as it is a water-soluble resin, but in particular, a water-soluble cellulose (for example, carboxymethyl cellulose) having a carboxylic acid or a salt thereof, an acrylic or methacrylic polymer or a copolymer thereof, a sulfone. Acrylic, methacrylic, vinyl, styrenic hydrophilic resins having acid groups or salts thereof, hydrophilic resins containing amide groups such as polyacrylamide or polyvinylpyrrolidone, hydrophilic resins having amino groups, hydrophilic properties having phosphoric acid or salts thereof Resins such as phosphate-modified starch described in JP-A-62-097892 are also exemplified.

It is also preferable to contain a compound having an onium group. The compounds having an onium group are described in detail in JP-A Nos. 2000-10292 and 2000-108538. In addition, a compound selected from the group of polymer compounds having a structural unit represented by poly (p-vinylbenzoic acid) in the molecule can also be used. Specific examples of these polymer compounds include a copolymer of p-vinylbenzoic acid and vinylbenzyltriethylammonium salt, a copolymer of p-vinylbenzoic acid and vinylbenzyltrimethylammonium chloride, and the like. .
A copolymer having a repeating unit containing at least one ethylenically unsaturated bond and a repeating unit containing at least one functional group that interacts with the support surface described in JP-A-2005-125749 is also preferable.
Among these, a polymer having a sulfonate skeleton is particularly preferable in terms of suppressing ink bleeding and making it difficult to stain.

  As a preferable embodiment of the composition for forming an ink receiving layer containing the above compound, one or more compounds selected from the group consisting of a compound having a perfluoroalkyl group and a compound having a dimethylsiloxane skeleton are used. And the aspect which contains 1-50 mass% and contains 99-50 mass% of hydrophilic resin used together if desired is mentioned.

  This ink receiving layer can be provided by the following method. That is, a method in which a solution obtained by dissolving the above organic polymer compound in water or an organic solvent such as methanol, ethanol, methyl ethyl ketone, 1-methoxy-2-propanol or a mixed solvent thereof is applied onto a support and dried. And adsorbing the compound by immersing the support in water or an organic solvent such as methanol, ethanol, methyl ethyl ketone, 1-methoxy-2-propanol, or a mixed solvent thereof, in which the organic polymer compound is dissolved. And then cleaning and drying with water or the like to provide an ink receiving layer. In the former method, a solution having a concentration of 0.005 to 10% by mass of the organic polymer compound can be applied by various methods. In the latter method, the concentration of the solution is 0.01 to 20% by mass, preferably 0.05 to 5% by mass, the immersion temperature is 20 to 90 ° C., preferably 25 to 50 ° C., and the immersion time is 0.1 second to 20 minutes, preferably 2 seconds to 1 minute. The former method is preferable because it suppresses adsorption to the substrate and is less likely to get dirty during printing.

Hereinafter, although an example and a comparative example explain the present invention in detail, the present invention is not limited to these.
(Production of support)
<Aluminum plate>
Si: 0.06 mass%, Fe: 0.30 mass%, Cu: 0.005 mass%, Mn: 0.001 mass%, Mg: 0.001 mass%, Zn: 0.001 mass%, Ti: Containing 0.03% by mass, the balance is prepared using Al and an inevitable impurity aluminum alloy, and after performing the molten metal treatment and filtration, an ingot having a thickness of 500 mm and a width of 1200 mm is obtained by a DC casting method. Created. After the surface was shaved with a chamfering machine with an average thickness of 10 mm, it was kept soaked at 550 ° C. for about 5 hours, and when the temperature dropped to 400 ° C., rolling with a thickness of 2.7 mm using a hot rolling mill A board was used. Furthermore, after performing heat processing using a continuous annealing machine at 500 degreeC, it finished by cold rolling to 0.24 mm in thickness, and obtained the aluminum plate of JIS1050 material. After making this aluminum plate width 1030mm, it used for the surface treatment shown below.

<Surface treatment>
The surface treatment was performed by continuously performing the following various treatments (a) to (j). In addition, after each process and water washing, the liquid was drained with the nip roller.
(A) Mechanical roughening treatment Using an apparatus as shown in FIG. 4, a suspension of a polishing agent (pumice) having a specific gravity of 1.12 and water is supplied as a polishing slurry to the surface of the aluminum plate. However, a mechanical surface roughening treatment was performed with a rotating roller-like nylon brush. In FIG. 1, 101 is an aluminum plate, 102 and 104 are roller brushes, 103 is a polishing slurry, and 105, 106, 107 and 108 are support rollers. The average particle size of the abrasive was 40 μm, and the maximum particle size was 100 μm. The material of the nylon brush was 6 · 10 nylon, the hair length was 50 mm, and the hair diameter was 0.3 mm. The nylon brush was planted so as to be dense by making a hole in a stainless steel tube having a diameter of 300 mm. Three rotating brushes were used. The distance between the two support rollers (φ200 mm) at the bottom of the brush was 300 mm. The brush roller was pressed until the load of the drive motor for rotating the brush became 7 kW plus with respect to the load before the brush roller was pressed against the aluminum plate. The rotating direction of the brush was the same as the moving direction of the aluminum plate. The rotation speed of the brush was 200 rpm.

(B) Alkali etching treatment The aluminum plate obtained above is subjected to an etching treatment by spraying using an aqueous solution having a caustic soda concentration of 2.6 mass%, an aluminum ion concentration of 6.5 mass%, and a temperature of 70 ° C. / M ^{2 was} dissolved. Then, water washing by spraying was performed.
(C) Desmutting treatment The desmutting treatment was performed by spraying with a 1% by mass aqueous solution of nitric acid at a temperature of 30 ° C. (containing 0.5% by mass of aluminum ions), and then washed with water by spraying. The nitric acid aqueous solution used for the desmut treatment was a waste liquid from a process of performing an electrochemical surface roughening treatment using alternating current in a nitric acid aqueous solution.

(D) Electrochemical roughening treatment An electrochemical roughening treatment was carried out continuously using an alternating voltage of 60 Hz. The electrolytic solution at this time was a 10.5 g / L aqueous solution of nitric acid (containing 5 g / L of aluminum ions and 0.007% by mass of ammonium ions) at a liquid temperature of 50 ° C. The AC power source waveform is electrochemical roughening treatment using a trapezoidal rectangular wave alternating current with a time ratio TP of 0.8 msec until the current value reaches a peak from zero, a duty ratio of 1: 1, and a trapezoidal rectangular wave alternating current. Went. Ferrite was used for the auxiliary anode. The current density was 30 A / dm ² at the peak current value, and the amount of electricity was 220 C / dm ² in terms of the total amount of electricity when the aluminum plate was the anode. 5% of the current flowing from the power source was shunted to the auxiliary anode. Then, water washing by spraying was performed.

(E) Alkali etching treatment The aluminum plate was sodium hydroxide concentration of 26 wt%, performed at 32 ° C. to etching treatment by spraying with an aluminum ion concentration of 6.5 wt% aqueous solution, the aluminum plate 0.25 g / ^{m 2} was dissolved, Removes the smut component mainly composed of aluminum hydroxide generated when electrochemical surface roughening treatment was performed using alternating current in the previous stage, and also melted the edge part of the generated pit to smooth the edge part. did. Then, water washing by spraying was performed.

(F) Desmut treatment Desmut treatment was performed by spraying with a 15% by weight aqueous solution of nitric acid at a temperature of 30 ° C. (containing 4.5% by weight of aluminum ions), and then washed with water by spraying. The nitric acid aqueous solution used for the desmut treatment was a waste liquid from a process of performing an electrochemical surface roughening treatment using alternating current in a nitric acid aqueous solution.

(G) Electrochemical surface roughening treatment An electrochemical surface roughening treatment was performed continuously using an alternating voltage of 60 Hz. The electrolytic solution at this time was a hydrochloric acid 7.5 g / L aqueous solution (containing 5 g / L of aluminum ions) at a temperature of 35 ° C. The AC power supply waveform has a time TP of 0.8 m until the current value reaches a peak from zero.
Using a trapezoidal rectangular wave alternating current with a sec, duty ratio of 1: 1, an electrochemical surface roughening treatment was performed using a carbon electrode as a counter electrode. Ferrite was used for the auxiliary anode. The current density was 25 A / dm ² at the peak current value, and the amount of electricity was 50 C / dm ² in terms of the total amount of electricity when the aluminum plate was the anode. Then, water washing by spraying was performed.

(H) Alkali etching treatment An aluminum plate was sprayed using an aqueous solution having a caustic soda concentration of 26% by mass and an aluminum ion concentration of 6.5% by mass at 32 ° C., and the aluminum plate was dissolved at 0.10 g / m ² . Removes the smut component mainly composed of aluminum hydroxide that was generated when electrochemical roughening treatment was performed using the alternating current of the previous stage, and also melted the edge part of the generated pit to smooth the edge part. did. Then, water washing by spraying was performed.

(I) Desmutting treatment A desmutting treatment by spraying was performed with a 25% by weight aqueous solution of sulfuric acid at a temperature of 60 ° C. (containing 0.5% by weight of aluminum ions), followed by washing with water by spraying.

(J) Anodizing treatment Anodizing treatment was performed using an anodizing apparatus having the structure shown in FIG. 5 to obtain a lithographic printing plate support used in the following Examples and Comparative Examples. Reference numeral 410 denotes an anodizing apparatus, 412 denotes a power supply tank, 414 denotes an electrolytic treatment tank, 416 denotes an aluminum plate, 418 and 426 denote electrolytes of the first electrolysis part and the second electrolysis part, 420 denotes a power supply electrode, 422 428 is a roller, 424 is a nip roller, 430 is an electrolytic electrode, 432 is a tank wall, and 434 is a DC power source. Sulfuric acid was used as the electrolytic solution supplied to the first and second electrolysis units. All electrolytes had a sulfuric acid concentration of 170 g / L (containing 0.5 mass% of aluminum ions) and a temperature of 38 ° C. Then, water washing by spraying was performed. The final oxide film amount was 2.7 g / m ² .

(K) Alkali metal silicate treatment The aluminum support obtained by anodizing treatment is immersed in a treatment tank of a 1% by mass aqueous solution of sodium silicate No. 3 at a temperature of 30 ° C. for 10 seconds. Acid salt treatment (silicate treatment) was performed. Thereafter, washing with water using well water was performed to obtain a support subjected to a surface silicate hydrophilization treatment. On the aluminum support after the alkali metal silicate treatment obtained as described above, an undercoat layer coating composition was applied and dried at 80 ° C. for 15 seconds to form a coating film. The coating amount of the coating film after drying was 6 mg / m ² .
The center line average roughness of the support thus obtained is 0.55 μm, the average wavelength of the large wave is 65 μm, the average opening diameter of the medium wave is 1.4 μm, the average opening diameter of the small wave is 0.14 μm, and the average opening of the small wave is The ratio of depth to aperture was 0.46.

[Create ink receiving layer]
<Coating solution composition>
・ The following polymer resin F-19 0.12 g
・ Methanol 100g
・ Water 1g
The above coating solution was applied on the support at a film thickness of 30 mg / m ² with a bar coater, and then dried in an oven at 80 ° C. for 1 minute.

Comparative Example 1
<Synthesis of dispersant>
A mixed solution of 96 g of octadecyl methacrylate, 4 g of 4- (2-methacryloyloxyethyloxycarbonyl) butyric acid, and 250 g of toluene was heated to a temperature of 80 ° C. under a nitrogen stream. As an initiator, 1.5 g of 2,2′-azobisisobutyronitrile (abbreviation AIBN) was added and reacted for 4 hours. I. B. N. Was added and heated to a temperature of 80 ° C. and reacted for 4 hours.
After the reaction mixture was cooled to room temperature, 6 g of allyl alcohol was added with stirring, followed by 10 g of dicyclohexylcarbodiimide (abbreviated DCC), 0.1 g of 4- (N, N-diethylamino) pyridine and chloride. A mixed solution of 30 g of methylene was added dropwise over 1 hour. The reaction was further continued for 3 hours to complete the reaction. Next, 10 g of 80% formic acid was added to the reaction mixture and the mixture was stirred for 1 hour. Insoluble matters were filtered off, and the filtrate was reprecipitated in 2.5 liters of methanol. After the precipitate was collected by filtration, it was dissolved again in 200 g of toluene, the insoluble matter was filtered off, and the filtrate was reprecipitated in 1 liter of methanol. The precipitate was collected by filtration and dried.
The yield of the obtained crosslinkable group-containing copolymer (C-VII) having the following structure was 85%, and the mass average molecular weight was 4.6 × 10 ⁴ . The structure was identified by NMR and IR.

<Preparation of polymerized particles>
While stirring a mixed solution of 20 g of the dispersant, (b) 40 g of methyl methacrylate as a monomer, 60 g of methyl acrylate, and (a) 200 g of Isopar G as a nonaqueous solvent, the temperature Warmed to 70 ° C. As a polymerization initiator, A.I. I. V. N. Was added and reacted for 3 hours. In addition, initiator A.I. I. B. N. 1.0 g was added, and the mixture was heated to 80 ° C. and reacted for 4 hours. Subsequently, the temperature was raised to 100 ° C. and stirred for 1 hour to distill off unreacted monomers. After cooling, it was passed through a 200-mesh nylon cloth. The resulting white dispersion had a polymerization rate of 99.2%, a volume average particle size of 1.18 μm, and Mw of 5.5 × 10 ⁴ particles. The particle size was measured with CAPA-500 (manufactured by Horiba, Ltd.).
The dispersion obtained as described above is diluted with Isopar G so that the dispersion has a particle concentration of 20% by mass, and 5 g of Victoria Pure Blue is added thereto at 50 ° C. The reaction was performed for 4 hours. After completion of the reaction, 4 μm filter filtration was performed to obtain a blue colored dispersion.

<Create ink>
Isopar-G was further added to the colored dispersion to obtain an ink composition having an octadecene-half-maleic acid octadecylamide copolymer of 0.3% by mass and a particle concentration of 7% by mass as a charge control agent.
The ink composition has a viscosity of 1.5 mPa · sec (E-type viscometer, measured at a temperature of 20 ° C.), a surface tension of 23 mN / m (an automatic surface tension meter manufactured by Kyowa Interface Science Co., Ltd., measured at a temperature of 20 ° C.), The relative dielectric constant was 2.30 (measured with an LCR meter, AG-4411 manufactured by Ando Electric Co., Ltd.), and the specific conductivity of the entire ink was 1200 pS / cm, indicating a clear positive charge. The specific conductivity of the ink was measured using the above LCR meter and the liquid electrode (LP-05 type manufactured by Kawaguchi Electric Manufacturing Co., Ltd.) under the conditions of an applied voltage of 5 V and a frequency of 1 kHz.
Next, the ink composition is used as an ink jet recording apparatus, and a 100 dpi, 64 channel electrostatic ink jet head having the head structure shown in FIG. 1 is used. On the lithographic printing plate support obtained above, the ink is recorded at a drawing resolution of 600 dpi. A dot image composed of oily resin particles was formed. A clear dot with no dot diameter of 20 μm was obtained. In addition, stable dot formation was possible without image deterioration even after continuous discharge for 1 hour.
Next, the lithographic printing plate on which this dot image was formed was contact-heated on a hot plate LS35C (HAKKO Co.) at a temperature of 120 ° C. at which the dot image was completely melted for 16 seconds to fix the image portion.
The obtained lithographic printing plate is applied to a printing machine (Lilithon: manufactured by Komori Co., Ltd.), printing ink (Varius ink: manufactured by Dainippon Ink Co., Ltd.), and dampening water (IF-102: Fuji Photo Film Co., Ltd.). ))).
As a result, it was found that the dot image disappeared after 500 sheets and the printing durability was low. Table 1 below also shows the evaluation result of the discharge image, the evaluation result of the discharge stability, and the evaluation result of the printability. The evaluation criteria are as follows.

[Evaluation of ejected image]
About the dot diameter ○: The dot diameter of 30 μm or less Δ: The dot diameter of 31 to 40 μm diameter ×: The dot diameter of 41 μm or more [Evaluation of ejection stability]
○: Continuous discharge of 1 hour or more is possible. Δ: Continuous discharge of 10 minutes to 1 hour is possible. X: Continuous discharge of less than 10 minutes [Printability evaluation]
○: More than 10,000 printing plates △: 2000 to 10,000 printing cycles ×: 2000 printing cycles or less

Comparative Example 2
Components of the following composition were mixed and stirred to obtain a blue thermosetting ink.
SR506 10.0g
(Manufactured by SARTOMER; isonorbornyl acrylate which is a polymerizable compound)
NPGPODA Actilane 421 10.0g
(Manufactured by AKZO Novell; propoxy-modified neopentyl glycol diacrylate which is a polymerizable compound)
V-601 (dimethyl 2,2-azobis (isobutylate) 1.5 g
(Wako Pure Chemical Industries; polymerization initiator)
Victoria Pure Blue BOH 0.4g

Next, this ink was discharged using a shear mode piezo head (CA3 manufactured by Toshiba Tec Corporation: minimum droplet amount 6 pL, number of nozzles 318, nozzle density 150 nozzles / 25.4 mm). Specifically, a head scanning type drawing apparatus in which one head is mounted on a movable carriage was used. Ink is introduced into an ink tank having a pressure reducing function, the pressure in the ink is reduced to -40 kPa, and the dissolved gas in the ink is deaerated. The tube was introduced into the head. By controlling the height of the hydrostatic pressure tank with respect to the head, the internal pressure of the head is adjusted to −6.6 kPa, and the meniscus shape at the nozzle portion of the head is controlled. The head was circulated with a water circulation temperature controller (SCINICS CH-201) so that the ink temperature in the head was 45 ° C. The head drive voltage was 24 V, and ejection was performed in an 8-value multidrop mode or binary mode. The dot formation frequencies are 4.8 kHz and 12 kHz, respectively. The drawing pitch is an 8-value multi-drop mode with a head scanning direction of 600 dpi (head scanning speed 203 mm / s) × recording medium conveyance direction 600 dpi, and a binary mode with a head scanning direction of 1200 dpi (head scanning speed 254 mm / s) × recording medium conveyance direction. That is, bidirectional interlaced printing of the head was performed while sequentially moving the recording medium.
In the initial stage of ejection, an image with a dot diameter of 50 μm and no bleeding was obtained, but ink was clogged in 5 minutes.
Next, printing was carried out after fixing under the same fixing conditions as in Comparative Example 1. As a result, printing durability of 10,000 sheets or more was possible.

Comparative Example 3
When the thermosetting ink of Comparative Example 2 was used and the ink jet apparatus of Comparative Example 1 was used for ejection, no ink was ejected.

Example 1
0.1% by mass of SR506 (manufactured by SARTOMER; polymerizable compound), 0.1% by mass of NPGPODA Actilane 421 (manufactured by AKZO Novell; polymerizable compound) with respect to the total mass of the ink components of Comparative Example 1, V- 601 (dimethyl 2,2-azobis (isobutyrate) was added to 0.02% by mass, and the charge adjusting agent octadecene-semimaleic acid was adjusted so that the specific conductivity of the whole ink was 1200 pS / cm. An ink was prepared by adjusting the amount of octadecylamide copolymer added.
As a result of evaluation in the same manner as in Comparative Example 1, the dot diameter was 20 μm, and stable dot formation was possible without image deterioration even when ejected continuously for 1 hour. On the other hand, the printing durability was improved to 2000 sheets.

Example 2
SR506 (manufactured by SARTOMER; polymerizable compound) is 1.0% by mass, NPGPODA Actilane 421 (manufactured by AKZO Novell; polymerizable compound) is 1.0% by mass, and V- 601 (dimethyl 2,2-azobis (isobutyrate) was added so as to be 0.2% by mass, and the charge adjusting agent octadecene-hemimaleic acid was adjusted so that the specific conductivity of the whole ink was 1200 pS / cm. An ink was prepared by adjusting the amount of octadecylamide copolymer added.
As a result of evaluation in the same manner as in Comparative Example 1, the dot diameter was 27 μm, and stable dot formation was possible without image deterioration even when ejected continuously for 1 hour. On the other hand, the printing durability was improved to 10,000 sheets.

Example 3
10% by mass of SR506 (manufactured by SARTOMER; polymerizable compound) and NPGPODA Actilane 421 (AKZO Novel) with respect to the total mass of the ink components of Comparative Example 1.
Company: Polymerizable compound) was added in an amount of 10% by mass and V-601 (dimethyl 2,2-azobis (isobutylate) in an amount of 1.0% by mass. The specific conductivity of the entire ink was 1200 pS / cm. Thus, an ink was prepared by adjusting the amount of addition of the charge adjusting agent octadecene-half-maleic acid octadecylamide copolymer.
As a result of evaluation in the same manner as in Comparative Example 1, the dot diameter was 30 μm, and stable dot formation was possible without image deterioration even when ejected continuously for 1 hour. On the other hand, the printing durability was improved to 20000 sheets.

It is a whole lineblock diagram showing typically an example of an ink jet printer used for the present invention. It is a perspective view which shows the structure of the inkjet head of the inkjet recording device of this invention (In order to make it intelligible, the edge of the guard electrode in each discharge part is not drawn). FIG. 3 is a side sectional view showing a distribution state of charged particles when the number of ejection units of the inkjet head shown in FIG. 2 is large (corresponding to an arrow XX in FIG. 2). It is a side view which shows the concept of the process of the brush lining used for the mechanical roughening process in preparation of the support body for lithographic printing plates of this invention. It is the schematic of the anodizing apparatus used for the anodizing process in preparation of the support body for lithographic printing plates of this invention.

Explanation of symbols

G Injected ink droplet P Recording medium Q Ink flow R Charged particle 1 Inkjet recording apparatus 2 Discharge head 3 Ink circulation system 4 Head driver 5 Position control means 6A to 6C Conveying belt stretching roller 7 Conveying belt 8 Conveying belt position detecting means 9 Electrostatic adsorption means 10 Static elimination means 11 Mechanical means 12 Feed roller 13 Guide 14 Image fixing means 15 Guide 16 Recording medium position detection means 17 Discharge fan 18 Solvent vapor adsorbent 38 Ink guide 40 Support bar portion 42 Ink meniscus 44 Insulating layer 46 First ejection electrode 48 Insulating layer 50 Guard electrode 52 Insulating layer 56 Second ejection electrode 62 Floating conductive plate 64 Coating film 66 Insulating member 70 Inkjet head 72 Ink flow path 74 Substrate 75, 75A, 75B Opening 76, 76A, 76B Ejection part 78 Ink guide part 101 Aluminum 102, 104 Roller brush 103 Abrasive slurry liquid 105, 106, 107, 108 Support roller 410 Anodizing device 412 Power supply tank 414 Electrolytic treatment tank 416 Aluminum plate 418, 426 Electrolytic solution 420 Power supply electrode 422, 428 Roller 424 Nip roller 430 Electrolysis Electrode 432 Tank wall 434 DC power supply

Claims (4)

  An ink composition for inkjet recording, comprising at least (A) a dispersion medium, (B) resin particles, (C) a charge control agent, (D) a polymerization initiator, and (E) a polymerizable compound.   The ink composition for ink jet recording according to claim 1, wherein the resin particles (B) are colored with a colorant. (A) a step of ejecting the ink composition for ink jet recording according to claim 1 or 2 onto an ink receptor; and (b) applying heat or heat and light to the ejected ink composition. Forming a hydrophobic image of the ink composition on the ink receptor by curing the ink composition.   A lithographic printing plate produced by the method for producing a lithographic printing plate according to claim 3.

Images