JP2597190B2 - Liquid developer for electrostatic photography - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a liquid developer for electrostatography comprising at least a resin dispersed in a carrier liquid having an electric resistance of not less than 10 ⁹ Ωcm and a dielectric constant of not more than 3.5. In particular, the present invention relates to a liquid developer having excellent redispersibility, storage stability, stability, image reproducibility, and fixability.

(Prior Art) A general liquid developer for electrophotography is a petroleum-based resin such as an organic or inorganic pigment or dye such as carbon black, nigrosine or phthalocyanine blue and a natural or synthetic resin such as alkyd resin, acrylic resin, rosin or synthetic rubber. Dispersed in a liquid with high insulation and low dielectric constant such as aliphatic hydrocarbons, and added with a polarity controlling agent such as a polymer containing metal soap, lecithin, linseed oil, higher fatty acid, and vinylpyrrolidone. .

In such a developer, the resin is dispersed in the form of particles having a diameter of several nm to several hundred nm as insoluble latex particles,
In the conventional liquid developer, the soluble dispersion stabilizing resin and the polarity controlling agent were easily diffused into the solution due to insufficient bonding between the soluble dispersion stabilizing resin and the polarity controlling agent and the insoluble latex particles. For this reason, there has been a defect that the soluble dispersion stabilizing resin is detached from the insoluble latex particles due to long-term storage or repeated use, and the particles settle, coagulate, accumulate or the polarity becomes unclear. Further, since the particles once aggregated and deposited are difficult to re-disperse, the particles remain adhered to various parts of the developing device, leading to failure of the developing device such as contamination of an image area and clogging of a liquid feeding pump.

In order to improve these drawbacks, means for chemically bonding the soluble dispersion stabilizing resin and the insoluble latex particles have been devised and disclosed in US Pat. No. 3,990,980. However, the dispersion stability of these liquid developers against spontaneous sedimentation of particles has been improved to some extent, but it is still insufficient, and when used in an actual developing device, the toner adhered to each part of the device becomes a coating film. In addition, it is difficult to re-disperse, and furthermore, it is not sufficient for re-dispersion stability which can be used practically, for example, it causes a failure of the apparatus, stains of a copied image, and the like. Further, in the method for producing resin particles described above, in order to produce monodisperse particles having a narrow particle size distribution, there are remarkable restrictions on the combination of a dispersion stabilizer to be used and a monomer to be insolubilized. As a result, particles having a large particle size distribution containing a large amount of coarse particles or polydisperse particles having two or more average particle diameters were obtained. In addition, it was difficult to obtain a desired average particle size with monodisperse particles having a narrow particle size distribution, and large particles of 1 μm or more or very fine particles of 0.1 μm or less were formed. Further, there is a problem that the dispersion stabilizer to be used must be produced through a complicated and time-consuming production process.

Furthermore, in order to improve the above-mentioned drawbacks, insoluble dispersed resin particles of a copolymer of a monomer to be insolubilized and a monomer containing a long-chain alkyl moiety or a monomer containing two or more polar components. The method of improving the degree of dispersion of the particles, redispersibility, storage stability is described in JP-A-60-179951 and JP-A-62-17975.
No. 151868 and the like.

(Problems to be Solved by the Invention) On the other hand, in recent years, a method of printing a large number of 5,000 or more sheets using a master plate for offset printing by an electrophotographic method has been attempted. It has become possible to print 10,000 sheets or more in plate size. Further, the operation time of the electrophotographic plate making system has been shortened, and improvement in speeding up the development-fixing process has been performed.

Dispersed resin particles produced according to the means disclosed in JP-A-60-179951 and JP-A-62-151868 are still fixed in terms of particle dispersibility and redispersibility when the development speed is increased. In the case where the time was shortened or in the case of a large plate size (for example, A-3 size or larger) master plate, the performance was not always satisfactory in terms of printing durability.

The present invention solves the problems of the conventional liquid developer as described above.

SUMMARY OF THE INVENTION An object of the present invention is to provide a liquid developer which has a fast development-fixing process and has excellent dispersion stability, re-dispersibility and fixability even in an electrophotographic plate making system using a large-size master plate. That is.

Another object of the present invention is to provide a liquid developer capable of producing an offset printing master having excellent printing ink oil sensitivity and printing durability by electrophotography.

Another object of the present invention is to provide a liquid developer suitable for various kinds of electrophotography and various kinds of transfer in addition to the above-mentioned applications.

Still another object of the present invention is to provide a liquid developer that can be used in any system where a liquid developer can be used, such as ink jet recording, cathode ray tube recording, and recording of various change processes such as pressure change or electrostatic change. That is.

(Means for Solving the Problems) An object of the present invention is to provide a liquid developer for electrostatography comprising at least a resin dispersed in a non-aqueous solvent having an electric resistance of 10 ⁹ Ωcm or more and a dielectric constant of 3.5 or less. In the above, the dispersed resin particles are soluble in the non-aqueous solvent in the presence of a resin that is soluble in the non-aqueous solvent and does not contain a graft group that polymerizes with a monomer, but is insolubilized by polymerization. Monofunctional monomer (A) and the following general formula (I)
Carboxyl group, sulfo group, hydroxyl group only at one end of the main chain of the polymer consisting of repeating units represented by
Formyl group, amino group, phosphono group, and (R ⁰ represents an —R ¹ group or an —OR ¹ group, and R ¹ represents a hydrocarbon group). An oligomer having a number average molecular weight of 10 ⁴ or less formed by bonding at least one polar group selected from the group consisting of (B) is a copolymer resin particle obtained by a polymerization reaction of a solution containing at least one kind of each of (B), and is achieved by a liquid developer for electrostatography.

General formula (I) In the general formula (I), V ⁰ represents -O-, -S-, -CO
O -, - OCO -, - CH 2 OCO- or represents a -CH ₂ COO-.

Y ⁰ represents a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms.

X ¹ and X ² may be the same or different from each other;
-, - S -, - CO -, - CO 2 -, - OCO -, - SO 2 -, (Y ¹ represents the same symbol as Y ⁰ above).

R ² and R ³ may be the same or different from each other, may be substituted, or (X ³ and X ⁴ may be the same or different from each other, and have the same symbols as X ¹ and X ² above, and R ⁴ is the number of carbon atoms which may be substituted. It indicates 1 to 18 hydrocarbon group, Y ² is representative of the Y ⁰ indicating the same symbol and] hydrocarbon group having 1 to 18 carbon atoms.

a ¹ and a ² may be the same or different from each other, and represent a hydrogen atom, a halogen atom, a cyano group, a hydrocarbon group, —COO—R ⁵
Or —COO—R ⁵ via a hydrocarbon (R ⁵ represents a hydrogen atom or a hydrocarbon group which may be substituted).

m, n and p may be the same or different;
Represents an integer of 4. However, m + n is 1 or more.

 Hereinafter, the liquid developer of the present invention will be described in detail.

As the carrier liquid having an electrical resistance of 10 ⁹ Ωcm or more and an inductivity of 3.5 or less used in the present invention, preferably a linear or branched aliphatic hydrocarbon, alicyclic hydrocarbon, or aromatic hydrocarbon, and a halogen thereof. Substitutes can be used. For example, octane, isooctane, decane, isodecane, decalin, nonane, dodecane, isododecane, cyclohexane, cyclooctane, cyclodecane, benzene, toluene, xylene, mesitylene, isoper E, isoper G, isoper H, isoper L (Isoper; Exxon; (Product name), Shellsol 70, Cielsol 71
(Shelsol; trade name of Shell Oil Company), Amsco
OMS, Amsco 460 solvent (Amsco; trade name of Spirits) or the like is used alone or in combination.

Non-aqueous dispersion resin particles, which are the most important components in the present invention (hereinafter sometimes referred to as latex particles)
Is produced by polymerizing a monomer (A) and an oligomer (B) in a non-aqueous solvent in the presence of a dispersion stabilizing resin (a so-called polymerization granulation method).

Here, as the non-aqueous solvent, basically, any solvent that is miscible with the carrier liquid of the liquid developer for electrostatography can be used.

That is, the solvent used for producing the dispersed resin particles may be any solvent that is miscible with the carrier liquid, and is preferably a linear or branched aliphatic hydrocarbon, alicyclic hydrocarbon, or aromatic hydrocarbon. Hydrogen and halogen-substituted products thereof are exemplified. For example, hexane, octane, isooctane, decane, isodecane, decalin, nonane, dodecane, isododecane, isoper E, isoper G, isoper H, isoper L, Cielsol 70, Cielsol 71, Amsco OMS, Amsco 460 solvent alone or a mixture thereof Used.

Solvents that can be used in combination with these organic solvents include alcohols (eg, methyl alcohol,
Ethyl alcohol, propyl alcohol, butyl alcohol, fluorinated alcohol, etc., ketones (eg, acetone, methyl ethyl ketone, cyclohexanone, etc.), carboxylic esters (eg, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl propionate, propionate) Ethyl ether, etc.), ethers (eg, diethyl ether, dipropyl ether, tetrahydrofuran, dioxane, etc.), halogenated hydrocarbons (eg, methylene dichloride, chloroform, carbon tetrachloride, dichloroethane,
Methyl chloroform, etc.).

The non-aqueous solvent used by mixing these, after polymerization granulation,
It is desirable to evaporate under heating or under reduced pressure.However, as a latex particle dispersion, even if brought into the liquid developer, there is a problem if the liquid resistance of the developer can satisfy the condition of 10 ⁹ Ωcm or more. No.

Usually, it is preferable to use the same solvent as the carrier liquid at the stage of producing the resin dispersion. As described above, linear or branched aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, halogenated Hydrocarbons and the like.

In a non-aqueous solvent, a dispersion stabilizing resin required to make the solvent-insoluble copolymer formed by copolymerizing the monomer (A) and the oligomer (B) into a stable resin dispersion, It is a resin that does not contain a graft group that polymerizes with a monomer, and a conventionally known dispersion stabilizing resin can be used.

That is, various synthetic resins or natural resins soluble in a non-aqueous solvent are used alone or in combination of two or more. For example, an alkyl chain or alkenyl chain having 6 to 32 carbon atoms [these aliphatic groups may contain a substituent such as a halogen atom, a hydroxy group, an amino group, an alkoxy group, or an oxygen atom, a sulfur atom, Esters of acrylic acid, methacrylic acid, or crotonic acid having a heteroatom such as a nitrogen atom through which a carbon-carbon bond of the main chain may be present]; higher fatty acid vinyls having 6 to 22 carbon atoms; alkyl vinyl ethers Or a polymer such as an olefin such as butadiene, isoprene, and diisobutylene, or a copolymer of a combination of two or more. Further, as described above, a monomer that forms a polymer soluble in a non-aqueous solvent and one of the following various monomers in a proportion within a range in which the obtained copolymer is soluble in a non-aqueous solvent A copolymer obtained by polymerizing the above can also be used.

Examples of the monomers include vinyl acetate; allyl acetate; methyl, ethyl, or propyl esters of unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, and itaconic acid; styrene derivatives (eg, styrene Unsaturated vinylic acid such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid or anhydride thereof; hydroxyethyl methacrylate, hydroxyethyl acrylate, diethylaminoethyl methacrylate, N -Vinylpyrrolidone, acrylamide, acrylonitrile, 2-chloroethyl methacrylate, 2,2,2-
Examples thereof include monomers containing various polar groups such as a hydroxy group, an amino group, an amide group, a cyano group, a sulfonic acid group, a carbonyl group, a halogen atom, and a hetero ring, such as trifluoroethyl methacrylate.

Alternatively, in addition to the above synthetic resin, alkyd resin,
Natural resins such as alkyd resins, linseed oil, and modified polyurethane resins modified with various fatty acids can also be used.

The monomer (A) in the present invention may be any monofunctional monomer which is soluble in a non-aqueous solvent but insolubilized by polymerization. Specifically, for example, a monomer represented by the general formula (II) can be mentioned.

General formula (II) Wherein (II), T is _{-COO -, - OCO-, CH 2} OCO -, - CH
₂ COO-, -O-, Represents Here, Z ¹ represents a hydrogen atom or an optionally substituted aliphatic group having 1 to 18 carbon atoms (for example, a methyl group, an ethyl group, a propyl group, a butyl group, a 2-chloroethyl group, a 2-chloroethyl group).
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 A 3-methoxypropyl group).

Z is a hydrogen atom or an optionally substituted aliphatic group having 1 to 6 carbon atoms (e.g., methyl, ethyl, propyl, butyl, 2-chloroethyl, 2,2-dichloroethyl, 2,2 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-morpholinoethyl group, 2-carboxyethyl group, 3-carboxypropyl group, 4-carboxybutyl group, 2-phosphoethyl Group, 3-sulfopropyl group, 4-sulfobutyl group, 2
-Carboxyamidoethyl group, 3-sulfamidopropyl group, 2-N-methylcarboxamidoethyl group, cyclopentyl group, chlorocyclohexyl group, dichlorohexyl group, etc.).

b ¹ and b ^2, which may be the same or different, each represent the same contents as a ¹ or a ² in the general formula (I).

Specific monomers (A) include, for example, those having 1 to 1 carbon atoms.
6 vinyl esters or allyl esters of aliphatic carboxylic acids (acetic acid, propionic acid, butyric acid, monochloroacetic acid, trifluoropropionic acid, etc.); unsaturated acids such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, and maleic acid Alkyl esters or amides of a carboxylic acid having 1 to 4 carbon atoms which may be substituted (for example, methyl group, ethyl group, propyl group, butyl group, 2-chloroethyl group, 2-bromoethyl group, 2-fluoroethyl group as the alkyl group) Group, trifluoroethyl group, 2-hydroxyethyl group, 2
-Cyanoethyl group, 2-nitroethyl group, 2-methoxyethyl group, 2-methanesulfonylethyl group, 2-benzenesulfonylethyl group, 2- (N, N-dimethylamino)
Ethyl 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-methyl) Styrene, vinylnaphthalene, chlorostyrene, dichlorostyrene, bromostyrene, vinylbenzenecarboxylic acid, vinylbenzenesulfonic acid, chloromethylstyrene, hydroxymethylstyrene, methoxymethylstyrene, N, N-dimethylaminomethylstyrene, vinylbenzenecarboxamide, Unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, and itaconic acid;
Maleic acid, cyclic anhydride of itaconic acid; acrylonitrile; methacrylonitrile; a heterocyclic compound containing a polymerizable double bond group (specifically, for example, "Polymer Data Handbook-Basic Edition" edited by the Society of Polymer Science, Japan, p175-184, compounds described in Baifukan (1986), for example, N-vinylpyridine, N-vinylimidazole, N-vinylpyrrolidone, vinylthiophene, vinyltetrahydrofuran, vinyloxazoline, vinylthiazole, N-vinylmorpholine and the like ) And the like.

 Two or more monomers (A) may be used in combination.

The oligomer (B) is an oligomer having a number average molecular weight of 10 ⁴ or less, which is formed by bonding the above-mentioned specific polar group to only one end of the main chain of a polymer comprising a repeating unit represented by the general formula (I). It is.

In the general formula (I), the hydrocarbon groups contained in a ¹ , a ² , Y ⁰ , Y ¹ and Y ² each have the indicated carbon number (as an unsubstituted hydrocarbon group). May be substituted.

In the general formula (I), V ₀ is -O-, -S-, -COO
-, - OCO -, - CH 2 OCO- or represents a -CH ₂ COO-.

Y ⁰ preferably represents a hydrogen atom or an optionally substituted aliphatic group having 1 to 18 carbon atoms. Preferred aliphatic groups include alkyl groups having 1 to 18 carbon atoms which may be substituted (for example, methyl group, ethyl group, propyl group, butyl group, heptyl group, hexyl group, octyl group, decyl group, dodecyl group, Hexadecyl group, octadecyl group, 2-chloroethyl group, 2-bromoethyl group, 2-cyanoethyl group, 2
-Methoxycarbonylethyl group, 2-methoxyethyl group, 3-bromopropyl group and the like, and an optionally substituted alkenyl group having 4 to 18 carbon atoms (for example, a 2-methyl-1-propenyl group, a 2-butenyl group, 2-pentenyl group, 3-
A methyl-2-pentenyl group, a 1-pentenyl group, a 1-hexenyl group, a 2-hexenyl group, a 4-methyl-2-hexenyl group, etc., an optionally substituted aralkyl group having 7 to 12 carbon atoms (eg, benzyl Group, phenethyl group, 3-phenylpropyl group, naphthylmethyl group, 2-naphthylethyl group, chlorobenzyl group, bromobenzyl group, methylbenzyl group, ethylbenzyl group, methoxybenzyl group, dimethylbenzyl group, dimethoxybenzyl group, etc.) And an optionally substituted alicyclic group having 5 to 8 carbon atoms (for example, a cyclohexyl group, a 2-cyclohexylethyl group, a 2-cyclopentylethyl group, etc.).

X ¹ and X ² may be the same or different from each other;
-, - S -, - CO -, - COO -, - OCO -, - SO 2 -, (Y ¹ represent the same symbol and the Y ⁰⁾ represent. More preferably, -O-, -CO-, -COO-, -OCO- or Represents

R ² and R ³ may be the same or different from each other, may be substituted, or Having 1 to 18 carbon atoms (an aliphatic group such as an alkyl group, an alkenyl group, an aralkyl group or an alicyclic group). Is shown. Preferred specific examples of these aliphatic groups include the same contents as the above-mentioned preferable aliphatic groups for Y ⁰ . However, X ³ and X ⁴ may be the same or different.
X ¹ represents the same symbol as X ² , R ⁴ represents an optionally substituted alkylene group having 1 to 18 carbon atoms, alkenylene group or aralkyl group, and Y ² represents the same symbol as Y ⁰ described above. .

Further specific examples of R ² and R ³ include: [R ⁶ and R ^{7 each} represent a hydrogen atom, an alkyl group having 1 to 12 carbon atoms (preferably 1 to 6 carbon atoms), a halogen atom, or the like], CH
= CH, (X ³ , X ⁴ , Y ² , R ⁴ , and p have the same meaning as the above symbols).

a ¹ and a ² may be the same or different from each other, and are preferably a hydrogen atom, a halogen atom (for example, a chlorine atom,
Bromine atom), cyano group, alkyl group having 1 to 3 carbon atoms (eg, methyl group, ethyl group, propyl group, etc.), -CO
O-R ⁵ or -CH ₂ COOR ⁵ (R ⁵ is a hydrogen atom or a carbon atoms 1 to 1
8 represents an alkyl group, an alkenyl group, an aralkyl group, an alicyclic group or an aryl group, which may be substituted, and specifically represents the same contents as those described for Y ⁰ above) Express.

m, n and p may be the same or different;
Represents an integer of 4. However, m + n ≧ 1.

Specific examples of the repeating unit represented by the general formula (I) as described above are further described below. However, the content of the present invention is not limited to these.

In the following, a represents H or CH ₃ ; R represents a C _1-18 alkyl group; R ′ represents a hydrogen atom or a C _1-18 alkyl group; k ₁ , k ₂
Represents an integer of 1 to 12; l ₁ and l _{2 each} represent an integer of 1 to 100.

The oligomer (B) used in the present invention may contain another repeating unit as a copolymer component together with the repeating unit represented by the general formula (I).

As the other copolymer component, any compound may be used as long as it is a monomer copolymerizable with the monomer corresponding to the repeating unit of the general formula (I). For example, unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, crotonic acid, maleic acid, vinyl acetic acid, and 4-pentenoic acid, and esters or amides of these unsaturated carboxylic acids;
22 fatty acid vinyl esters or allyl esters; vinyl ethers; styrene and styrene derivatives;
Heterocyclic compounds containing an unsaturated bond are exemplified. Specifically, for example, the compounds exemplified for the above-mentioned monomer (A) and the like can be mentioned, but it should not be construed that the invention is limited thereto.

In the total of the repeating units of the oligomer (B), the repeating unit represented by the general formula (I) accounts for 40% by weight of the whole.
Is preferably contained, more preferably 60
~ 100% by weight.

When the content of the component represented by the general formula (I) is less than 40% by weight, the mechanical strength of the image area formed by the dispersed resin particles is not sufficiently maintained. The effect of improving the performance cannot be seen.

A polar group which is bonded to only one end of a polymer main chain having a number average molecular weight of 1 × 10 ⁴ or less containing at least one kind of the repeating unit represented by the general formula (I); In the formula, R ⁰ represents a —R ¹ group or —OR ¹ group, and R ¹ preferably represents a hydrocarbon group having 1 to 18 carbon atoms. More preferably, the hydrocarbon group of R ¹ is an aliphatic group having 1 to 8 carbon atoms which may be substituted (for example, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a butenyl group,
Pentenyl group, hexenyl group, 2-chloroethyl group, 2
A cyanoethyl group, a cyclopentyl group, a cyclohexyl group, a benzyl group, a phenethyl group, a chlorobenzyl group, a bromobenzyl group, or the like; Group, bromophenyl group, methoxyphenyl group, cyanophenyl group, etc.).

Further, in a polar group of the present invention, the amino group, -NH _2, -NHR ⁸
Or Represents R ⁸ and R ⁹ represent a hydrocarbon group having 1 to 18 carbon atoms, and preferably represent a hydrocarbon group having 1 to 8 carbon atoms,
Specifically, the same meaning as the hydrocarbon group of the above-described R ^1.

Still more preferably, as the hydrocarbon group for R ¹ , R ⁸ and R ⁹ , an alkyl group having 1 to 4 carbon atoms which may be substituted, a benzyl group which may be substituted, or a phenyl group which may be substituted. No.

Here, the polar group has a chemical structure in which the polar group is directly bonded to one end of the polymer main chain of the oligomer (B) or is bonded via an arbitrary linking group. Examples of the group connecting the component (I) and the polar group include a carbon-carbon bond (single bond or double bond) and a carbon-hetero atom bond (hetero atoms include, for example, an oxygen atom, a sulfur atom, a nitrogen atom, and a silicon atom). Atoms), and any combination of heteroatom-heteroatom bond atomic groups.

Among the oligomers (B) of the present invention, preferred are those represented by the formula (IIIa) or (IIIb).

Formula (IIIa) Formula (IIIb) In the formulas (IIIa) and (IIIb), a ¹ , a ² , R ² , R ³ , X ¹ ,
X ² , V ⁰ , Y ⁰ , m and n represent the same contents as the symbols of the formula (I).

Q represents the above-mentioned polar group bonded to one end of the formula (I).

W is a simple bond or [R ¹⁰ and R ¹¹ represent a hydrogen atom, a halogen atom (eg, a fluorine atom, a chlorine atom, a bromine atom, etc.), a cyano group, a hydroxy group, an alkyl group (eg, a methyl group, an ethyl group, a propyl group)] , CH = CH, -O-, -S-, -COO -, - SO ₂ -, -NHCOO-, -NHCONH-, [R ¹² and R ¹³ each independently represent a hydrogen atom, a hydrocarbon group or the like having the same content as the above-mentioned Y ⁰ ] or a single linking group selected from an atomic group or an arbitrary combination thereof. Represents a linking group.

When the upper limit of the number average molecular weight of the oligomer (B) exceeds 1 × 10 ⁴ , the printing durability decreases. On the other hand, if the molecular weight is too small, soiling tends to occur, so it is preferably 1 × 10 ³ or more.

Further, in the polymer main chain of the oligomer (B), a phosphono group, a carboxyl group, a sulfo group, a hydroxyl group, a formyl group, an amino group, Those which do not contain a copolymer component containing a polar group are preferred.

The oligomer (B) of the present invention comprising a specific polar group bonded only to one end of the polymer main chain can be prepared by a method in which various reagents are reacted with the ends of a living polymer obtained by conventionally known anionic or cationic polymerization ( Ion polymerization method), radical polymerization using a polymerization initiator and / or chain transfer agent containing a specific polar group in the molecule (radical polymerization method), or ionic polymerization or radical as described above It can be easily produced by a synthesis method such as a method of converting a polymer having a terminal reactive group obtained by a polymerization method into a specific polar group of the present invention by a polymer reaction.

Specifically, P. Dreyfuss, RPQuirk, Encycl.Polym.Sc
Review of i.Eng., 7 , 551 (1987), Yoshiki Chujo, Yuya Yamashita, "Dyes and Chemicals", 30 , 232 (1985), Akira Ueda, Susumu Nagai, "Science and Industry", 60 , 57 (1986) And the method described in the literature cited therein.

Examples of the polymerization initiator containing a specific polar group in the above-mentioned molecule include 4,4′-azobis (4-cyanovaleric acid), 4,4′-azobis (4-cyanovaleric chloride), , 2'-azobis (2-cyanopropanol),
2,2'-azobis (2-cyanopentanol), 2,2'-
Azobis [2-methyl-N- (2-hydroxyethyl)
-Propioamide], 2,2'-azobis {2-methyl-
N- [1,1-bis (hydroxymethyl) ethyl] propioamide}, 2,2'-azobis {2-methyl-N- [1,1
-Bis (hydroxymethyl) -2-hydroxyethyl]
Propioamide｝, 2,2'-azobis [2- (5-methyl-2-imidazolin-2-yl) propane], 2,2 '
-Azobis [2- (4,5,6,7-tetrahydro-1H-1,3-
Diazepin-2-yl) propane], 2,2'-azobis [2- (3,4,5,6-tetrahydropyrimidin-2-yl) propane], 2,2'-azobis [2- (5-hydroxy -3,4,5,6-tetrapyrimidin-2-yl) propane], 2,2'-azobis {2- [1- (2-hydroxyethyl) -2-imidazolin-2-yl] propane} 2,
2'-azobis [N- (2-hydroxyethyl) -2-
Methyl-propionamidine], 2,2'-azobis [N
-(4-aminophenyl) -2-methylpropionamidine].

Examples of the chain transfer agent having a specific polar group in the molecule include a mercapto compound, a disulfide compound, an iodine-substituted compound and the like, and preferably a mercapto compound. For example, thioglycolic acid, 2-mercaptopropionic acid, thiomalic acid, 2-
Mercaptoethanesulfonic acid, 2-mercaptoethanol, 2-mercaptoethylamine, thiosalicylic acid, α
-Thioglycerin, 2-phosphonoethyl mercaptan,
Hydroxythiophenol and derivatives of these mercapto compounds are exemplified.

These polymerization initiators and / or chain transfer agents are used at a ratio of 0.5 to 20% by weight based on the total amount of the monomer corresponding to the repeating unit represented by the general formula (I) and other polymerizable monomers. And preferably 1 to 10% by weight.

Preferred examples of the oligomer (B) used in the present invention are represented by the general formula (IIIa) or (IIIb), and the sites represented by QW- in these formulas are more specifically exemplified below. However, the scope of the present invention is not limited to this.

In the following, k ₁ represents an integer of 1 or 2, k ₂ represents an integer of ₂ to 16, and k ₃ represents an integer of 1 or 3.

(B) -1: HOOCCH _{2 k1} S- (B) -3: HOOC (CH _{2 k2} OOC (CH _{2 k1} S− (B) -4: HOOC (CH _{2 k2} NHCO (CH _{2 k1} S− (B) -8: H ₂ N (CH ₂ k ₂ S- (B) -12: HO ₃ S (CH ₂ ) ₂ S- (B) -29: HOOC (CH ₂ ) ₂ NH (CH _{2 k1} S− (B) -30: HOOC (CH _{2 k2} CONH (CH _{2 k2} S−) The dispersion resin of the present invention comprises a monomer (A) And at least one of the oligomers (B). Importantly, if the resin synthesized from these monomers is insoluble in the non-aqueous solvent, a desired dispersed resin can be obtained. Specifically, the oligomer (B) represented by the general formula (I) is preferably used in an amount of 0.05 to 10% by weight, more preferably 0.1 to 5% by weight, based on the insoluble monomer (A). More preferably, the molecular weight of the dispersing resin of the present invention is from 10 ³ to 10 ⁶ , preferably from 0.3 to 3% by weight.
10 ^{4 to} 5 × 10 ⁵ .

In order to produce the dispersion resin used in the present invention as described above, generally, the dispersion stabilizing resin and the monomer (A) as described above are used.
And the oligomer (B) may be heated and polymerized in a non-aqueous solvent in the presence of a polymerization initiator such as benzoyl peroxide, azobissobutyronitrile, and butyllithium. Specifically, a method of adding a polymerization initiator to a mixed solution of the dispersion stabilizing resin, the monomer (A) and the oligomer (B), and a method of dissolving the monomer (A) in a solution in which the dispersion stabilizing resin is dissolved. And a method of dropping the oligomer (B) together with the polymerization initiator,
Alternatively, a method of optionally adding the remaining monomer mixture together with the polymerization initiator to a mixed solution containing the whole amount of the dispersion stabilizing resin and a part of the mixture of the monomer (A) and the oligomer (B), And a method of optionally adding a mixed solution of a dispersion stabilizing resin and a monomer (A) and an oligomer (B) together with a polymerization initiator in a non-aqueous solvent, and the like. be able to.

The total amount of the monomer (A) and the oligomer (B) is about 5 to 80 parts by weight, preferably 10 to 50 parts by weight, based on 100 parts by weight of the non-aqueous solvent.

The soluble resin as the dispersion stabilizing resin is used in an amount of 1 to 100 parts by weight, preferably 5 to 50 parts by weight, based on 100 parts by weight of the total amount of the monomer (A) and the oligomer (B) used above. .

The amount of the weight initiator is suitably from 0.1 to 5% by weight of the total amount of the monomer (A) and the oligomer (B).

The polymerization temperature is about 50 to 180 ° C., preferably 60 to 180 ° C.
~ 120 ° C. The reaction time is preferably 1 to 15 hours.

In the non-aqueous solvent used for the reaction, the alcohols described above,
When polar solvents such as ketones, ethers and esters are used in combination, or when the unreacted product of the monomer (A) to be polymerized and granulated remains, the boiling point of the solvent or monomer is increased. It is preferable to remove by heating or distilling off under reduced pressure.

As described above, the non-aqueous dispersion resin produced according to the present invention exhibits very stable dispersibility at the same time as being present as fine particles having uniform particle size distribution, and can be used repeatedly for a long time especially in a developing device. However, even if the dispersibility is good and the developing speed is improved, re-dispersion is easy, and it is not recognized at all that any contamination occurs on each part of the apparatus.

Further, when fixed by heating or the like, a strong film was formed, and excellent fixability was exhibited.

Further, the liquid developer of the present invention has a rapid development-fixing process and is excellent in dispersion stability, re-dispersibility and fixability even when a large-size master plate is used.

When the resin particles of the present invention are used as a liquid developer, the details of the reason why the redispersion and the fixability of the toner image are significantly improved as described above are unknown, but in the polymerization granulation method of the resin particles of the present invention, Even after polymerization granulation without using the oligomer (B), the above effect was not observed even if the oligomer (B) was added by post-addition. This is considered that the oligomer (B) used in the resin particles of the present invention has modified the surface of the resin particles.

That is, because the polar group specified and bonded only to one end of the polymer main chain is polymerized and granulated in a non-aqueous solvent, it is bonded to the resin particles by an anchor effect, and the polymer main chain is It is presumed that one of the main factors is that the part modifies the surface of the resin particles and improves the affinity with the dispersion medium.

If desired, a colorant may be used in the liquid developer of the present invention. The colorant is not particularly specified, and various conventionally known pigments or dyes can be used.

In the case of coloring the dispersion resin itself, for example, as one of the coloring methods, there is a method of physically dispersing the dispersion resin in a dispersion resin using a pigment or a dye. I have. For example, magnetic iron oxide powder, powdered lead iodide, carbon black, nigrosine, alkali blue, Hansa Yellow, quinaclodon red, phthalocyanine blue and the like can be mentioned.

As another method of coloring, there is a method of dyeing a dispersion resin with a preferable dye as described in JP-A-57-48738. Alternatively, as another method, there is a method in which a dispersing resin and a dye are chemically bonded as disclosed in JP-A-53-54029.
As described in JP-A-44-22955 and the like, there is a method of producing a dye-containing copolymer by using a monomer containing a dye in advance when producing by a polymerization granulation method.

Various additives may be added to the liquid developer of the present invention, if desired, for the purpose of enhancing charging characteristics or improving image characteristics. For example, Yuji Harazaki, "Electrophotography", Vol.
And those specifically described on page 44 are used.

For example, di-2-ethylhexylsulfosuccinic acid metal salt, naphthenic acid metal salt, higher fatty acid metal salt, lecithin,
Examples include poly (vinylpyrrolidone) and a copolymer containing a semi-maleic acid amide component.

The amounts of the main components of the liquid developer of the present invention will be described below.

The amount of the toner particles containing a resin and a coloring agent used as a main component is preferably 0.5 parts by weight to 50 parts by weight based on 1,000 parts by weight of the carrier liquid. When the amount is less than 0.5 part by weight, the image density is insufficient, and when the amount is more than 50 parts by weight, fogging to a non-image portion is liable to occur. Further, the carrier liquid soluble resin for stabilizing the dispersion is also used as desired, and about 0.5 to 100 parts by weight can be added to 1000 parts by weight of the carrier liquid.
The charge control agent as described above is used for 1,000 parts by weight of the carrier liquid.
0.001 to 1.0 part by weight is preferred. If desired, various additives may be added. The upper limit of the total amount of these additives is regulated by the electric resistance of the developer. That is, if the electrical resistance of the liquid developer in a state where the toner particles are removed becomes lower than 10 ⁹ Ωcm, it becomes difficult to obtain a high-quality continuous tone image.
It is necessary to control the amount of each additive within this limit.

(Examples) Examples of the present invention will be described below, but the contents of the present invention are not limited thereto.

Oligomer Production Example 1: Production of Oligomer B-1 2,3-diacetoxypropyl methacrylate was added to 100
g, a mixed solution of 5 g of 3-mercaptopropionic acid, 150 g of toluene and 50 g of methanol were heated to a temperature of 70 ° C. while stirring under a nitrogen stream. 1.5 g of 2,2'-azobis (isobutyronitrile (abbreviation: AIBN) was added and reacted for 4 hours. 0.4 g of AIBN was further added and reacted for 4 hours.After cooling, the reaction solution was added to methanol / water [(4 / 1) Volume ratio]
The precipitate was reprecipitated in 2 l of the mixed solution, the methanol solution was separated by decantation, and the viscous substance was dried to obtain 75 g of a colorless viscous substance.

The number average molecular weight of the polymer was 3,300.

Oligomer Production Examples 2 to 13: Oligomer B-2 to B-13
The production of each oligomer B-2 to B was carried out in the same manner as in Production Example 1, except that the mercapto compound shown in Table 1 below was used in place of 5 g of 3-mercaptopropionic acid in Production Example 1.
-13 was produced. The number average molecular weight of the obtained oligomer is
It was 2,500-5,000.

Oligomer Production Examples 14 to 33: Oligomer B-14 to B-33
The production of each oligomer B- was carried out in the same manner as in Production Example 1 except that monomers corresponding to Table 2 were used instead of 2,3-diacetoxypropyl methacrylate in Production Example 1.
14-B-33 were produced. The number average molecular weight of the obtained oligomer was 2,500 to 3,000.

Production Example 34 of Oligomer: Production of Oligomer B-34 A mixed solution of 100 g of 2- (n-octylcarbonyloxy) ethyl crotonate, 150 g of toluene and 50 g of ethanol was heated to a temperature of 75 ° C. while stirring under a nitrogen stream. 2,
8 g of 2'-azobis (cyanovaleric acid) (abbreviation: ACV) was added and reacted for 5 hours, and 2 g of ACV was further added and reacted for 4 hours. After cooling the obtained reaction solution, methanol / water [(4 /
1) Volume ratio] The mixture was reprecipitated in a mixed aqueous solution, and an aqueous methanol solution was separated by decantation. yield
With 70 g, the number average molecular weight of the polymer was 2,600.

Oligomer Production Examples 35 to 43: Production of Oligomers B-35 to B43 In Production Example 34, except that the azobis compound of Table 3 below was used in place of the polymer initiator ACV, the same operation as in Production Example 34 was performed. Each oligomer B-35 to B-43 was prepared. The number average molecular weight of the obtained oligomer was 2,000 to 4,000.

Production Example 1 of Latex Particle 1: D-1 20 g of poly (octadecyl methacrylate), 100 g of vinyl acetate, 1.0 g of oligomer B-16 and 38 g of Isopar H
0 g of the mixed solution was heated to 70 ° C. while stirring under a nitrogen stream. 2,2'-azobis (isovaleronitrile) (abbreviation)
(AIVN) was added and reacted for 2 hours.
3 g was added and reacted for 2 hours. Twenty minutes after the addition of the initiator, cloudiness occurred and the reaction temperature rose to 88 ° C. The temperature was raised to 100 ° C. and the mixture was stirred for 2 hours to distill off unreacted vinyl acetate. After cooling, the mixture was passed through a 200-mesh nylon cloth, and the resulting white dispersion was a latex having a degree of polymerization of 88% and an average particle size of 0.24 μm.

Latex Particle Production Examples 2 to 30: 2 to D-30 In Latex Particle Production Example 1, except that the dispersion stabilizing resin and oligomer were replaced with the respective compounds shown in Table 4 below,
Each latex particle was produced under the same conditions as in Production Example 1.
The conversion of each latex particle was 80-85%.

Production Example 31 of Latex Particles: A mixture of 20 g of D-31 poly (octadecyl methacrylate), 100 g of vinyl acetate, 5 g of crotonic acid, 1.5 g of oligomer B-3 and 468 g of Isopar E was stirred at a temperature of 70 while stirring under a nitrogen stream. Warmed to ° C. After adding 1.3 g of AIVN and reacting for 6 hours, the temperature was raised to 100 ° C., and the mixture was stirred for 1 hour, and the remaining vinyl acetate was distilled off. After cooling, the mixture was passed through a 200-mesh nylon cloth, and the resulting white dispersion was a latex having a polymerization rate of 85% and an average particle size of 0.23 μm.

Production Example 32 of Latex Particles: D-32 Poly (dodecyl methacrylate) 20 g, Vinyl acetate 100
g, a mixed solution of 6.0 g of 4-pentenoic acid, 1.0 g of oligomer B-13 and 380 g of Isopar G were heated to a temperature of 75 ° C. while stirring under a nitrogen stream. 0.7 g of AIBN was added and reacted for 4 hours, and 0.5 g of AIBN was further added and reacted for 2 hours. After cooling, the mixture was passed through a nylon cloth of 200 mesh, and the obtained white dispersion was a latex having an average particle size of 0.24 μm.

Production Example 33 of latex particles: D-33 Dodecyl methacrylate / 2-hydroxyethyl methacrylate (copolymerization ratio: 8/2 molar ratio) copolymer 18 g, vinyl acetate 85 g, N-vinylpyrrolidone 15 g, oligomer B-39
Was heated to a temperature of 75 ° C. while stirring under a nitrogen stream while stirring. 1.7 g of AIBN added 4
After reacting for 0.5 hour, 0.5 g of AIBN was added and reacted for 2 hours. After cooling, the mixture was passed through a 200-mesh nylon cloth, and the obtained white dispersion was a latex having an average particle size of 0.20 μm.

Production Example 34 of Latex Particles: D-34 A mixed solution of 20 g of poly (octadecyl methacrylate), 100 g of isopropyl methacrylate, 1.0 g of oligomer B-15 and 470 g of n-decane was heated to a temperature of 70 ° C. while stirring under a nitrogen stream. did. 1.0 g of AIVN was added and reacted for 2 hours. Blue turbidity starts several minutes after the initiator is charged, and the reaction temperature is 90 ° C
Up. After cooling, coarse particles were removed through a 200-mesh nylon cloth, and the resulting white dispersion had an average particle size of 0.
It was a 45 μm latex.

Production Example 35 of Latex Particles: D-35 25 g of poly (tridecyl methacrylate), 100 of styrene
g, a mixed solution of 0.6 g of oligomer B-19 and 380 g of Isopar H were heated to a temperature of 60 ° C. while stirring under a nitrogen stream. Add 0.6 g of AIVN and react for 4 hours.
0.3 g was added and reacted for 3 hours. After cooling, it was passed through a 200-mesh nylon cloth, and the obtained white dispersion had an average particle size of 0.28 μm.
m latex.

Production Example 36 of Latex Particles (Comparative Example A) In Production Example 1 of latex particles, oligomer B-
Except for Example 1, the procedure was the same as in Production Example 1. The resulting white dispersion was a latex having a conversion of 85% and an average particle size of 0.25 μm.

Production Example 37 of Latex Particles (Comparative Example B) A mixed solution of 18 g of poly (octadecyl methacrylate), 100 g of vinyl acetate, 1.0 g of octadecyl methacrylate, and 385 g of Isopar H was prepared. The resulting white dispersion had a conversion of 85% and an average particle size of 0.22.
μm latex. (Latex equivalent to JP-A-60-179951) Production Example 38 of Latex Particles (Comparative Example C) 18 g of poly (octadecyl methacrylate), 100 g of vinyl acetate, 1 g of monomer (I) having the following chemical structure, and Isopar H Was used as a mixed solution of 385 g, and the other operations were the same as in Production Example 1. The resulting white dispersion had a conversion of 86% and an average particle size of 0.24.
μm latex. (Latex equivalent to JP-A-62-151868) Monomer [I] Example 1 dodecyl methacrylate / acrylic acid (copolymerization ratio: 95 /
5 weight ratio) copolymer 10g, nigrosine 10g and shell sol 7
30 g of 1 was put together with glass beads in a paint shaker (Tokyo Seiki Co., Ltd.) and dispersed for 4 hours to obtain a fine dispersion of nigrosine.

The resin dispersion D-1 of Production Example 1 of latex particles was added to 30
g, 2.5 g of the above nigrosine dispersion, 15 g of FOC-1400 (manufactured by Nissan Chemical Industries, Ltd .: tetradecyl alcohol), 0.08 [octadecene-half-maleic acid octadecylamide copolymer] 0.08
The liquid developer for electrostatography was prepared by diluting g into 1 of the shell sol 71.

(Comparative Developers A to C) Three kinds of liquid developers A, B, and C for comparison were prepared by replacing the resin dispersion in the above Production Example with the following resin particles.

Comparative Liquid Developer A: Latex Particle Production Example 36 Resin Dispersion Comparative Liquid Developer B: Latex Particle Production Example 37 Resin Dispersion Comparative Liquid Developer C: Latex Particle Production Example 38 Resin Dispersion The liquid developer is used as a developer for the fully automatic plate making machine ELP404V (manufactured by Fuji Photo Film Co., Ltd.), and the ELP Master II type electrophotographic photosensitive material (manufactured by Fuji Photo Film Co., Ltd.) is exposed and developed. Processed. Plate making speed is 7
Performed at plate / min. In addition, 200 ELP Master II types
After the zero-sheet processing, the presence or absence of toner contamination on the developing device was observed. The blackening rate (image area) of the copied image was determined using a 30% original.

 The results are shown in Table-5.

When the respective developers were subjected to plate making under the plate making conditions described above, only the case of the present invention was a developer which did not cause staining of the developing device and had a clear image on the 2000th plate making plate.

On the other hand, a master plate for offset printing (ELP master) obtained by making a plate from each developer is printed by a conventional method, and the number of printed sheets until the occurrence of missing characters or solid blurring in the printed image is compared. The present invention, Comparative Example A
The master plate obtained by using the developer of Comparative Example C did not generate even with 10,000 sheets or more, and the master plate using Comparative Example B generated with 8000 sheets.

As described above, only the developer using the resin particles of the present invention as a developer did not cause any stain on the developing device, and also significantly improved the number of printed master plates.

That is, in the case of Comparative Example A, there was no problem with the number of printed sheets, but the developing device was significantly stained and could not withstand continuous use.

Further, in the case of Comparative Examples B and C, if the plate making speed is as fast as 5 sheets / min (conventionally, plate making speed of 2 to 3 sheets / min), the developing device (especially on the back electrode plate) And the quality of the copied image on the plate is affected (reduction of Dmax, blurring of thin lines, etc.) after about 2,000 sheets. The number of printed master plates was satisfactory in Comparative Example C, but decreased in Comparative Example B.

These results show that the resin particles of the present invention are clearly superior.

Example 2 100 g of the white dispersion obtained in Production Example 2 of latex particles
And 1.5 g of Sumicaron Black were heated to a temperature of 100 ° C. and heated and stirred for 4 hours. By cooling to room temperature and passing through a 200 mesh nylon cloth to remove the remaining dye,
A black resin dispersion having an average particle size of 0.24 μm was obtained.

32 g of the above black resin dispersion, FOC-1600 (Nissan Chemical Co., Ltd.)
The liquid developer was prepared by diluting 20 g of hexadecyl alcohol) and 0.05 g of zirconium naphthenate into one of the shell sols 71.

When this was developed by the same apparatus as in Example 1, 2000
Even after sheet development, no toner adhesion stains occurred on the apparatus.

Further, the image quality of the obtained master plate for offset printing was clear, and the image quality of the printed matter after printing 10,000 sheets was also very clear.

Example 3 100 g of the white dispersion obtained in Production Example 32 of latex particles
And a mixture of 3 g of Victoria Blue B at a temperature of 70 ° C. to 80 ° C.
And stirred for 6 hours. After cooling to room temperature, it was passed through a 200-mesh nylon cloth to remove the remaining dye, and the average particle size was 0.2.
A 25 μm blue resin dispersion was obtained.

32 g of the above blue resin dispersion, zirconium naphthenate 0.0
A liquid developer was prepared by diluting 5 g to 1 of Isopar H.

This was developed with the same apparatus as in Example 1, and
Even after the development of 00 sheets, no toner adhesion stains were observed on the apparatus. The image quality of the obtained master plate for offset printing was clear, and the image quality of the printed matter after printing 10,000 sheets was also clear.

Example 4 White resin dispersion 32 obtained in Production Example 3 of latex particles
g, 2.5 g of the nigrosine dispersion obtained in Example 1, FOC-1800
A liquid developer was prepared by diluting 15 g of octadecyl alcohol (manufactured by Nissan Chemical Co., Ltd.) and 0.02 g of half-docosanilamide of a copolymer of diisobutylene and maleic anhydride into 1 of Isopar G.

When this was developed by the same apparatus as in Example 1, 2000
Even after sheet development, no toner adhesion stains were observed on the apparatus. Further, the image quality of the obtained master plate for offset printing and the image quality of the printed matter after 10,000 sheets were printed were clear.

After the developer was allowed to stand for three months, the same treatment as above was performed, but it was not different from that before the lapse of time.

Example 5 10 g of poly (decyl methacrylate) and 3 parts of Isopar H
0 g and 8 g of alkali blue were put together with glass beads in a paint shaker and dispersed for 2 hours to obtain a fine dispersion of alkali blue.

30 g of the white resin dispersion D-23 obtained in Production Example 23 of latex particles, 4.2 g of the above-mentioned alkali blue dispersion, and 0.06 g of a half-docosanyl amidated copolymer of diisobutylene and maleic anhydride were added to Isopar G. By diluting to 1, a liquid developer was prepared.

When this was developed by the same apparatus as in Example 1, 2000
Even after sheet development, no toner adhesion stains were observed on the apparatus. In addition, the image quality of the obtained master plate for offset printing and the image quality of printed matter after 10,000 sheets were printed were very clear.

Examples 6 to 27 In Example 5, the D-
Except for using each latex of Table 6 below in place of 23,
A liquid developer was prepared in the same manner as in Example 5.

When this was developed by the same apparatus as in Example 1, 2000
Even after sheet development, no toner adhesion stains occurred on the apparatus.

Further, the image quality of the obtained master plate for offset printing was clear, and the image quality of the printed matter after printing 10,000 sheets was also very clear.

After the developer was allowed to stand for three months, the same treatment as above was performed, but it was not different from that before the lapse of time.

(Effect of the Invention) According to the present invention, a developer having excellent dispersion stability, redispersibility, and fixability was obtained. In particular, even when used under very high plate-making speed, the developing device was not stained, and both the image quality of the obtained master plate for offset printing and the image quality of printed matter after 10,000 sheets were printed were very clear. .

Claims (1)

(57) [Claims] 1. An electrophotographic liquid developer comprising at least a resin dispersed in a non-aqueous solvent having an electric resistance of not less than 10 ⁹ Ωcm and a dielectric constant of not more than 3.5. In the presence of a resin which is soluble and does not contain a graft group which polymerizes with the monomer, the monofunctional monomer (A) which is soluble in the non-aqueous solvent but is insolubilized by polymerization and A carboxyl group, a sulfo group, a hydroxyl group, a formyl group, an amino group, a phosphono group, and a carboxyl group, a sulfo group, a hydroxyl group, and a (R ⁰ represents an —R ¹ group or —OR ¹ group, and R ¹ represents a hydrocarbon group), and an oligomer having a number average molecular weight of 10 ⁴ or less formed by bonding at least one polar group selected from the group consisting of A liquid developer for electrophotography, which is a copolymer resin particle obtained by polymerizing a solution containing at least one component (B). General formula (I) In the general formula (I), V ⁰ represents -O-, -S-, -COO
-, - OCO -, - CH 2 OCO- or represents a -CH ₂ COO-. Y ⁰ represents a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms. X ¹ and X ² may be the same or different from each other, -O-,
-S -, - CO -, - CO 2 -, - OCO -, - SO 2 -, (Y ¹ represents the same symbol as Y ⁰ above). R ² and R ³ may be the same or different from each other, may be substituted, or (X ³ and X ⁴ may be the same or different from each other, and have the same symbols as X ¹ and X ² above, and R ⁴ is the number of carbon atoms which may be substituted. It indicates 1 to 18 hydrocarbon group, Y ² is representative of the Y ⁰ indicating the same symbol and] hydrocarbon group having 1 to 18 carbon atoms. a ¹ and a ² may be the same or different from each other, and represent a hydrogen atom,
Represents a halogen atom, a cyano group, a hydrocarbon group, -COO-R ⁵ through -COO-R ⁵ or hydrocarbon (R ⁵ represents a hydrogen atom or an optionally substituted hydrocarbon group). m, n and p may be the same or different;
Represents an integer. However, m + n is 1 or more.