JPH0830040A - Liquid developer and its production - Google Patents

Abstract

PURPOSE:To lessen the change in image density with lapse of time and generation of stains in a developing device and to enable development of brighter images by dispersing specific colored resin particles into a nonaq. dispersion medium. CONSTITUTION:This liquid developer is formed by dispersing the colored resin particles formed by including pigments and/or dyes (hereafter described as the pigments, etc.) in the nonaq. dispersion medium and microcapsulating these pigments or dyes by a resin insoluble in the nonaq. dispersion medium. In such a case the inclusions of the colored resin particles are pigments, etc., and pigment dispersant for dispersing the pigments, etc., are included therein at need. The pigments, etc., to be used are not particularly restricted and, for example, inorg. pigments, org. pigments and dyes known from heretofore, and various mixtures are usable. The pigment dispersants are required to be dispersible in the nonaq. dispersion medium or the monomer of the microcapsule wall material. Further, the number average particle size of the colored resin particles is preferably 0.05 to 1mum.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid developer for developing an electrostatic latent image in an electrophotographic process or the like and a method for producing the liquid developer.

[0002]

2. Description of the Related Art In an electrophotographic process, a method of developing an electrostatic latent image is roughly classified into a dry developing method and a wet developing method. The dry developing method is a method in which a colorant powder is sprinkled and adhered onto an electrostatic latent image, and has the advantage of being excellent in handleability and toner storage stability. However, in recent years, in applications such as video printers, high-quality images with high resolution have been demanded, and in order to obtain such high resolution, it is necessary to make the particle size of the developer finer. However, in the dry developing method, there are problems such as aggregation between toner particles, spread of charge amount distribution, and poor cleaning performance as the particle size is made smaller, and there is a limit to support high resolution. .

The wet development method uses a liquid developer in which a dye or a pigment as a colorant is dispersed in an insulating medium, and the particle size can be made smaller than that of the dry development method. It is possible to obtain resolution and gradation. Therefore, in recent years, research and development of such liquid developers have been actively pursued.

As such a liquid developer, for example,
JP-A-3-196154 and JP-A-3-2237
The liquid developer disclosed in Japanese Patent Publication No. 70 is known. In these liquid developers, a pigment is dispersed in a hydrocarbon-based non-aqueous dispersion medium containing a resin component.

Further, Japanese Patent Laid-Open No. 63-151868,
Japanese Unexamined Patent Publication No. 3-212565 and Japanese Unexamined Patent Publication No. 3-225.
Japanese Patent No. 353 discloses a liquid developer obtained by mixing and dispersing non-aqueous dispersion-polymerized particles and a pigment in a non-aqueous dispersion medium.

In these conventional liquid developers, the resin and the pigment are mixed in the non-aqueous dispersion medium, but since they are prepared and mixed separately, the mobility in the non-aqueous dispersion medium is increased. Etc. are different. Therefore, the degree of adhesion to the surface of the photoreceptor is different, the composition of the liquid developer changes over time,
There is a problem that the image density changes.

Further, in such a conventional liquid developer,
Since the resin component and the resin particles are simply adsorbed on the pigment, there is a problem that fog and toner residue due to the aggregation of the pigment are likely to occur and the inside of the device is easily soiled due to the adhesion of the pigment.

As a method for solving such a problem,
A liquid developer is known in which resin particles containing a pigment in the resin are prepared by mixing the pigment in a molten resin, and the resin particles are dispersed in a non-aqueous dispersion medium. Such a liquid developer is disclosed, for example, in JP-A-63-301966-6.
No. 9, JP-A-63-5351, and JP-A-2.
-883 publication. In these liquid developers, the pigment and the resin particles are integrated,
The pigment and the resin particles behave integrally, no change in composition over time due to a difference in mobility, and no change in image density occurs. Further, since the pigment is contained inside the resin, the occurrence of stains in the developing device is small.

However, the resin particles obtained by melt-kneading such a pigment have a large particle diameter of about 1 to 10 μm, and since they have a wide particle diameter distribution, they contain a large amount of coarse particles.

Therefore, there is a problem in that the colored particles tend to settle in the liquid developer and a high-resolution image cannot be obtained. An object of the present invention is to solve such a conventional problem, reduce a change in image density with time, and reduce stains in a developing device to develop a clearer image. It is an object of the present invention to provide a liquid developer and a method for producing the same.

[0011]

The liquid developer of the present invention comprises:
A colored resin particle in which a pigment and / or a dye (hereinafter, simply referred to as “pigment or the like”) is encapsulated in a non-aqueous dispersion medium and microencapsulated with a resin insoluble in the dispersion medium. There is.

[Colored Resin Particles] The inclusion of the colored resin particles in the present invention is a pigment or the like, and if necessary, a pigment dispersant for dispersing the pigment or the like is included.

The pigment and the like, which are the inclusions of the colored resin particles, the pigment dispersant, and the microcapsule wall material will be described below. Pigments and the like The pigments and the like used in the present invention are not particularly limited and, for example, conventionally known inorganic pigments, organic pigments, dyes and mixtures thereof can be used.

The following can be mentioned as specific examples of the pigment.・ Magenta pigments: Azo lake type, monoazo type, quinacridone type, etc ... CI Pigment No. Red-57-1, Red-31, Red-
122 etc.-Cyan pigment: phthalocyanine-based etc .... CI Pigment N
o.Blue-60, Blue-15-6, Blue-15, Blue-15-2, Blue-1
5-3, Blue-15-4, etc.-Yellow pigment: Disazo type, benzimidazoline type, etc .... CI Pigment No.Yellow-12, -13, -14, -17, -5
5, -83, -154 etc. ・ Black pigments: carbon black, copper oxide, manganese dioxide, aniline black, activated carbon, magnetite, magnetic ferrite, non-magnetic ferrite, etc.

The following may be mentioned as specific examples of the dye. CI. Direct Black 19, 22, 154 CI. Direct Yellow 12, 16, 88 CI. Direct Red 9, 13, 17 CI. Direct Blue 78, 90 CI. Acid Black 8, 31, 52 CI. Acid Yellow 23, 25 CI. Acid Red 37, 52, 92, 94 CI. Acid Blue 9, 22 CI. Hood black 2

Pigment Dispersant As the pigment dispersant, it is necessary to disperse the pigment or the like in the non-aqueous dispersion medium or the monomer of the microcapsule wall material described later. Examples of such products include solsper 27000 (manufactured by ZENEKA) as a commercial product, and generally, acrylic resin, melamine resin, styrene-maleic acid copolymer, polyester resin, epoxy modified resin, butadiene modified resin, urethane. Resin etc. can be mentioned. From the freedom of design,
Acrylic resins are particularly preferred.

Microcapsule Wall Material The resin used as the microcapsule wall material for the colored resin particles in the present invention is a resin insoluble in the non-aqueous dispersion medium. As such a resin, a polyurethane resin and / or a polyurea resin is preferable.

[0018] The number average particle diameter of the colored resin particles in the particle size present invention of the colored resin particles is preferably from 0.05 to 1 [mu] m. In the present invention, the number average particle diameter of the colored resin particles is preferably as small as possible so long as it can be stably dispersed, but generally the number average particle diameter is 0.05 μm or more. If the number average particle size is too large, the colored resin particles tend to settle, the image becomes unclear, and the image density decreases. Further, if the particle size becomes large, it becomes impossible to obtain high resolution. The average particle size of the colored resin particles can be measured by using a particle size measuring device using light scattering or laser diffraction.

[Non-Aqueous Dispersion Medium] The non-aqueous dispersion medium in the liquid developer of the present invention is not particularly limited as long as it is generally used as a dispersion medium of the liquid developer, but usually the volume resistivity value Of 10 ¹⁰ Ω · cm or more is used. A dielectric constant of 3.5 or more is usually used. Examples of such a non-aqueous dispersion medium include aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, halogenated hydrocarbons, polysiloxanes, etc., and volatility, safety, toxicity, odor, etc. From this point of view, an isoparaffin petroleum solvent is suitable. Such isoparaffin petroleum solvents include Isopar M, Isopar G, Isopar H,
Isopar L, Isopar K (both manufactured by Esso),
Shell Sol 71 (manufactured by Shell Oil Co., Ltd.) and the like can be mentioned.

The liquid developer of the present invention is, for example, microencapsulated by encapsulating a pigment and the like by interfacially polymerizing the monomer A and the monomer B in the above non-aqueous dispersion medium. It can be obtained by producing colored resin particles.

Further, among monomers A and B, a monomer insoluble in the non-aqueous dispersion medium is dispersed and emulsified together with a pigment in the presence of a protective colloid, and the other monomer is added to this dispersion emulsion to perform interfacial polymerization. By doing so, microencapsulation can be achieved. Generally, since the monomer A is insoluble in the non-aqueous dispersion medium, the monomer A is dispersed and emulsified in the non-aqueous dispersion medium together with the pigment and the like, and the monomer B is dropped into the dispersion emulsion to carry out a polymerization reaction. , Forming microcapsule walls.

[Ratio of Colored Resin Particles to Non-Aqueous Dispersion Medium] In the liquid developer of the present invention, the ratio of the colored resin particles to the non-aqueous dispersion medium is not particularly limited, but a general liquid is used. The mixing ratio of the developer can be applied, and for example,
The concentration of the colored resin particles can be 1 to 45% by weight. If the concentration of the colored resin particles is too low, a clear image may not be obtained, and if the concentration of the colored resin particles is too high, interparticle agglomeration may easily occur. If the concentration is high during synthesis and storage, it can be appropriately diluted with a solvent before being supplied to the developing device.

[Charging of Colored Resin Particles] The colored resin particles in the liquid developer adhere to the surface of a photoconductor or the like by electrophoresing in a non-aqueous dispersion medium to develop an electrostatic latent image. Therefore, it is necessary to be charged in the non-aqueous dispersion medium. The charge for such charging can be imparted by introducing a polar group into the colored resin particles or adding a charge adjusting agent, as described later.

[Production Method of Liquid Developer] The liquid developer of the present invention can be produced, for example, by microencapsulating a pigment or the like by an interfacial polymerization method.

In the case of forming by microencapsulation interfacial polymerization method by interfacial polymerization method, for example, a compound having two or more active hydrogens is reacted with a compound having two or more functional groups capable of reacting with active hydrogens. It can be carried out. Hereinafter, these compounds will be described.

Compound having two or more active hydrogens (hereinafter referred to as "monomer A") As the active hydrogen, active hydrogens of primary amino group and hydroxyl group are preferable from the viewpoint of reactivity. Examples of compounds having two or more such active hydrogens include polyamine compounds and polyol compounds. Examples of the polyamine compound include hexamethylenediamine, m-xylylenediamine, iminobispropylamine, α, ω-bis-
Examples include (3-aminopropyl) -propylene glycol ether and 2-methylpentadiamine. As the polyol compound, ethylene glycol,
2-methyl-1,3-propanediol, 1,4-butanediol, 1,9-nonanediol, glycerol,
Examples include pentaerythritol. Monomer A
Is preferably insoluble in the non-aqueous dispersion medium.

Compound having two or more functional groups capable of reacting with active hydrogen (hereinafter referred to as "monomer B") As the functional group capable of reacting with active hydrogen, an isocyanate group is preferable from the viewpoint of reactivity. Examples of the compound having two or more functional groups capable of reacting with active hydrogen include a polyisocyanate compound. As the polyisocyanate compound, hexamethylene diisocyanate,
Toluene diisocyanate, isophorone diisocyanate, xylene diisocyanate, tetramethyl xylene diisocyanate, trimer of the above diisocyanate,
And an adduct of the above-mentioned diisocyanate with a polyhydric alcohol.

Mixing Ratio of Monomer A and Monomer B The equivalent ratio of Monomer B to Monomer A is 0.4 to 2
Is preferable, and more preferably 0.6 to 1.2.
Outside this range, the desired microcapsules may not be obtained.

Pigment Dispersant In the interfacial polymerization, the pigment dispersant as described above is preferably used in order to make the pigment and the like stably exist in the non-aqueous dispersion medium.

It is preferable to use a protective colloid for stabilizing the emulsion state of the protective colloid pigment and the like and the monomer A (monomer B in some cases) in a non-aqueous dispersion medium. As such a protective colloid, those having a hydrophobic portion and a hydrophilic portion in the molecule, which are generally used in interfacial polymerization, can be used.

Examples of the hydrophobic portion include a long chain hydrocarbon group and a polyorganosiloxane unit. Further, examples of the hydrophilic portion include a polyalkylene oxide unit. Examples of the protective colloid having such a hydrophobic portion and a hydrophilic portion include a block polymer having a polyorganosiloxane unit and a polyalkylene oxide unit, and an acrylic monomer having a polyalkylene oxide unit (trade name MA-50,1).
00, 150; a copolymer of an acrylic monomer having a long-chain hydrocarbon group (lauryl methacrylate, cetyl methacrylate, etc.), polyethylene glycol long-chain alkyl ether, sorbitan fatty acid ester and the like.

Phase Inversion Method In one of the preferred embodiments of the manufacturing method according to the present invention,
A pigment and the like and a monomer are dispersed by a phase inversion method and microencapsulated by an interfacial polymerization method. The interfacial polymerization by the phase inversion method can be performed by the following three steps.

First step: When a pigment dispersant is used, the pigment dispersant and the pigment are mixed to prepare a pigment dispersion paste. This pigment dispersion paste is added to the monomer A and dispersed to prepare a dispersion liquid.

Second step: The dispersion obtained in the first step is added to a non-aqueous dispersion medium in the presence of a protective colloid to disperse and emulsify it to prepare an emulsion. Third step: The monomer B is dropped into the emulsion obtained in the second step, and the monomer A and the monomer B are interfacially polymerized to obtain microcapsules.

As described above, in the preferred embodiment, the interfacial polymerization is carried out by the phase inversion method. However, the production method of the present invention is not limited to this, and the monomer A and the monomer B are directly dispersed in the non-aqueous dispersion medium. May be dispersed and emulsified in the presence of a protective colloid for interfacial polymerization.

[0036] Formulation ratio] pigments such as pigments or the like, the monomers A and B used, and the total weight of the pigment dispersing agent, it is preferable that the weight of the pigment is 5 to 25 wt%. If the proportion of the pigment or the like is too small, a clear image may not be obtained, and if the proportion is too large, the stability of the liquid developer may deteriorate.

Pigment dispersant The solid content of the pigment is preferably 5 to 30% by weight. If the proportion of the pigment dispersant is too small, the dispersion stability will be poor, and if it is too large, particles having the target particle size may not be obtained.

Based on the weights of the protective colloid monomer A, the pigment dispersant, and the pigment,
It is preferably 5 to 30% by weight. If it deviates from this range, it may not be possible to obtain particles having a desired particle size.

It is preferably 1 to 5 times, preferably 2 to 4 times the total weight of the monomers A and B used in the non-aqueous dispersion medium , the pigment dispersant and the pigment. If the amount of the non-aqueous dispersion medium is too small, the production becomes difficult, and if the amount of the non-aqueous dispersion medium is too large, it becomes economically disadvantageous.

[Charging of Colored Resin Particles] In the present invention, in order to charge the colored resin particles, a microcapsule wall material for the colored resin particles, a protective colloid used for interfacial polymerization, and a pigment dispersion in the colored resin particles are used. It is preferable that a polar group is introduced into any of the agents. Examples of such polar groups include carboxylic acid groups and metal salts thereof, sulfonic acid groups and metal salts thereof, anion groups such as metal chelate groups, and cationic groups such as amino groups and quaternary ammonium groups.

Of the polar groups to the pigment dispersant and protective colloid
Introduction Such a polar group can be introduced , for example, by copolymerizing the following reactive emulsifier and the like.

Reactive Emulsifier Having Anionic Group

[0043]

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Trade name: Antox-MS-60, manufactured by Nippon Emulsifier Co., Ltd.

[0045]

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Product name: ADEKA SOAP SE-10N, manufactured by Asahi Denka Co., Ltd.

[0047]

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Trade name: Aqualon HS-10, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.

[0049]

[Chemical 4]

Product name: Latemur S-180A, manufactured by Kao Corporation

[0051]

Embedded image

2-hydroxyethyl methacrylate with ε
-A compound obtained by ring-closing trimellitic anhydride with a compound having a hydroxyl group at the terminal with an average of 5 mol of caprolactone added, and reacting one of the carboxyl groups with a long-chain epoxy (Curular E). Compounds opened with ethyl methacrylate (for example, trade name: acrylic ester PA, manufactured by Mitsubishi Rayon Co., Ltd.)

Reactive emulsifier having a cationic group N, N-dimethylaminopropylacrylamide (trade name: DMAPAA, manufactured by Kojin Co., Ltd.) and a quaternized compound (trade name: DMAPAA-Q, manufactured by Kojin Co., Ltd.) ) A reactive emulsifier having an anionic group as described above or a reactive emulsifier having a cationic group, and an acrylic monomer having a polyethylene oxide moiety (trade name MA-
50, 100, 150; manufactured by Nippon Emulsifier Co., Ltd.) to prepare a pigment dispersant or a protective colloid.

As a copolymerization ratio, the reactive emulsifier having an anionic group or the reactive emulsifier having a cationic group is 5 to 25% by weight with respect to 40% by weight or more of an acrylic monomer having a polyethylene oxide moiety. The rest may be a (meth) acrylate, a polymerizable aromatic compound, a hydroxyl group-containing monomer or the like as shown below.

(Meth) acrylate; methyl acrylate, methyl methacrylate, ethyl acrylate,
Ethyl methacrylate, n-butyl acrylate, n
-Butyl methacrylate, isobutyl acrylate,
2-Ethylhexyl acrylate, lauryl methacrylate, phenyl acrylate, etc.-Polymerizable aromatic compound; Styrene, α-methylstyrene, vinyl ketone, t-butylstyrene, rosechlorostyrene, vinylnaphthalene, etc.-Hydroxyl group-containing monomer; 2-hydroxy Ethyl acrylate, 2-hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate, hydroxybutyl methacrylate, allyl alcohol, methallyl alcohol, etc.

Introduction of Polar Group into Capsule Wall Material When introducing an anionic group into the capsule wall material, for example, 2,5-dihydroxy-1,4-benzenediacetic acid can be added. . When a cationic group is introduced into the capsule wall material, for example, it is provided by adding diamine (trade name: EDR-148, manufactured by Mitsuishi Texaco Ltd.) in an amount of about 1.2 to 1.4 times the equivalent amount of the isocyanate. can do.

Addition of Charge Control Agent During or after the interfacial polymerization, the following charge control agents may be added to impart a charge to the colored resin particles. The addition amount is preferably 0.05 to 5% by weight of the colored resin particles.

Charge control agent for giving a positive charge Dioctyl sodium sulfosuccinate, zirconium octoate, copper oleate, metal naphthenate, ethylenediaminetetraacetic acid metal complex salt, quaternary ammonium compound and the like.

Charge control agents that give a negative charge: lecithin, barium peteronate, alkylsuccinimide, oil black BY, etc.

[0060]

The liquid developer of the present invention is a developer in which the coloring resin particles in which a pigment or the like is encapsulated and microencapsulated are dispersed in a non-aqueous dispersion medium. In the present invention, since the pigment and the like are microencapsulated, the pigment and the resin particles are integrated, and they move integrally in the non-aqueous dispersion medium and adhere to the surface of the photoreceptor or the like. Therefore, the composition does not change with time, and it is possible to prevent a decrease in image density with time and the occurrence of blurring of characters and the like.

Further, since the colored resin particles are formed by microencapsulation, the particle diameter can be made smaller than that of the conventional colored resin particles integrated by melt kneading or the like. Therefore, the sedimentation of the colored particles in the non-aqueous dispersion medium is suppressed, and the occurrence of defective image quality is eliminated.

In the production method of the present invention, colored resin particles containing a pigment and the like are produced by interfacial polymerization in a non-aqueous dispersion medium used for a liquid developer. According to the present invention, such a manufactured product can be used as it is or diluted with a non-aqueous dispersion medium to be used as a liquid developer. Therefore, it is not necessary to disperse the separately manufactured colored resin particles in the non-aqueous dispersion medium as in the conventional case, and the liquid developer can be manufactured by a simpler process.

The liquid developer of the present invention is useful in a wide variety of fields such as wet copying machines and electrophotographic plate making.

[0064]

EXAMPLES Polymers in which pigments are dispersed in colored resin particles (hereinafter referred to as "pigment dispersants") were prepared as in Synthesis Examples 1 to 3 below.

<Synthesis Example 1 (pigment dispersant)> Polyethylene glycol (Kishida Chemical Co .; PEG) was placed in a reaction vessel equipped with a stirring and heating device, a cooling pipe, a nitrogen introducing pipe and a temperature control.
-200) 300 g was charged, the temperature was raised to 80 ° C. with stirring while introducing nitrogen, and polyethylene glycol (15) monomethacrylate (manufactured by Nippon Emulsifier Co .; MA-
150) 60 g and a reactive emulsifier (manufactured by Nippon Emulsifier Co .; A
ntox-MS-60) (40 g) and dimethyl 2,2'-azobis (2-methylpropionate) (Wako Pure Chemical Industries, Ltd .; V-601) (2 g) were added dropwise over a period of 2 hours, and then 5 hours. The reaction was continued. GP of the obtained polymer
The number average molecular weight by C was 41,000.

<Synthesis Example 2 (pigment dispersant)> 300 g of ethylene glycol was charged into a reaction vessel, and polyethylene glycol monomethacrylate (manufactured by Nippon Emulsifier Co., Ltd .; MA-1).
50) 60 g and a reactive emulsifier (2-hydroxyethyl methacrylate with an average of 5 mol of ε-caprolactone added to the compound having a hydroxyl group at the terminal to open the trimellitic anhydride ring, and one of the carboxyl groups has a long-chain epoxy (cardurar E)) 40 g, dimethyl 2,2'-azobis (2-methylpropionate)
(Wako Pure Chemical Industries, Ltd .; V-601) A polymerization reaction was performed in the same manner as in Synthesis Example 1 except that 1 g of a mixed solution was added dropwise. The number average molecular weight of the obtained polymer was 39,000.

<Synthesis Example 3 (pigment dispersant)> 300 g of diethylene glycol was charged into a reaction vessel, and 60 g of polyethylene glycol (50) monomethacrylate (manufactured by Nippon Emulsifier Co., Ltd .; MA-50) and N, N-dimethylaminopropylmethacrylamide were prepared. (Manufactured by Kojinsha; DMAPMA) 4
A polymerization reaction was carried out in the same manner as in Synthesis Example 1 except that a mixed solution of 0 g and 1 g of dimethyl 2,2′-azobis (2-methylpropionate) (manufactured by Wako Pure Chemical Industries, Ltd .; V-601) was added dropwise. . The number average molecular weight of the obtained polymer was 38,0.
It was 00.

Protective colloids used for microencapsulation by the interfacial polymerization method were prepared as in Synthesis Examples 4 to 6 below. <Synthesis example 4 (protective colloid)> Polydimethylsiloxane having a molecular weight of 5000 and having an OH group at one end in a reaction vessel equipped with a stirring and heating device, a thermometer and a cooling tube (manufactured by Chisso Corporation;
FM-0421) 476.5 g, isophorone diisocyanate 23.5 g, and dibutyltin laurate 0.06 g were mixed and the reaction was continued while maintaining the temperature at 75 ° C. 8
When the isocyanate equivalent weight was measured after the lapse of time, the disappearance of the theoretical amount of isocyanate groups was confirmed. After lowering the temperature to room temperature, a molecular weight of 2,000 with an amino group at one end
Polyethylene glycol (manufactured by Mitsui Texaco Ltd .; Jeffamine M2070) (191.5 g) was added, the mixture was stirred at room temperature for 2 hours, and the reaction was further continued at 40 ° C. for 2 hours. IR
The amount of isocyanate detected in was very small. GPC
The number average molecular weight was 7160 and the weight average molecular weight was 9240.

<Synthesis Example 5 (Protective colloid)> 230 g of methyl ethyl ketone was placed in a reaction vessel equipped with a stirring and heating device, a thermometer, a nitrogen introducing tube and a cooling tube, and the temperature was raised to 80 ° C. while stirring in a nitrogen stream. Further, cetyl methacrylate (NFA; CMA) 65 g, polyethylene glycol (15) monomethacrylate (Nippon Emulsifier; MA-150) 15 g, methyl methacrylate 10
g, 10 g of acrylic acid, and a mixed solution of 1 g of 2,2'-azobis (cyanovaleric acid) (ACVA) were added dropwise for 2 hours, and then the reaction was continued for 5 hours. After the reaction, the solvent was removed using an evaporator. The non-volatile component of the obtained resin is 90%,
The number average molecular weight measured by GPC is 12,000.
Met.

<Synthesis example 6 (protective colloid)> 65 g of lauryl methacrylate, polyethylene glycol (10)
Monomethacrylate (manufactured by Nippon Emulsifier Co., Ltd .; MA-100)
15 g, methyl methacrylate 10 g, N, N-dimethylaminopropyl methacrylamide (manufactured by Kojin Co .; DMA
PMA) 10 g, dimethyl 2,2'-azobis (2-methylpropionate) (manufactured by Wako Pure Chemical Industries, Ltd .; V-60
1) The same polymerization reaction as in Synthesis Example 5 was performed except that 1 g of the mixed solution was dropped. The nonvolatile content of the obtained resin is 92%.
And the number average molecular weight measured by GPC is 11,0.
It was 00. Using the pigment dispersant and protective colloid obtained as described above, liquid developers of Examples 1 to 8 and Comparative Examples 1 to 6 shown below were prepared.

Example 1 20 g of phthalocyanine blue (manufactured by Dainichiseika Co., Ltd .; cyanine blue 4938), 80 g of polyethylene glycol (molecular weight 200), and a commercially available resin (E
NEKA; solspers 17000) 5 g and glass beads (Toshiba Ballotini; GB503M) 125 g
Was put in a sand grinder, 2000 rpm, 3
Time dispersion was performed. 70 g of the obtained pigment paste and 30 g of the protective colloid obtained in Synthesis Example 4 were mixed with Polytron 40
Mix at 00 rpm and keep stirring, Isopar M2
00 g was gradually added dropwise to emulsify. After transferring this to a reactor, 0.05 g of dibutyl tin urate was added thereto, and a 15% Isopar M solution of toluene diisocyanate (manufactured by Mitsubishi Kasei Co., Ltd .; TDI80) was allowed to stand at room temperature for 1 hour so as to be equivalent to the above polyethylene glycol. Was dropped. Two hours after the completion of the dropping, the temperature was raised to 45 ° C. and polymerization was performed for another two hours. 20 g of this and 5.4 g of zirconium octoate were put into 500 g of Isopar M and stirred to obtain a developer.

The particle size of the obtained particles was measured by a particle size measuring device SALAD2000A manufactured by Shimadzu Corporation and found to be 0.58 micron. When the particles were observed with a transmission electron microscope, the pigment had an encapsulated structure and was present in the particles. It was confirmed that this liquid developer was positively charged.

Examples 2 to 8 Developers having the formulations shown in Table 1 were prepared in the same manner as in Example 1. However, in Examples 7 and 8, the amount of isocyanate added was 0.7 equivalent to the polyamine.

[0074]

[Table 1]

Examples 2 to 8 prepared as described above
In the above, an acidic group or a basic group is introduced as a polar group into any of the pigment dispersant, the protective colloid, and the capsule wall material, and thereby the surface of the colored resin particles is charged positively or negatively. Table 2 collectively shows the types and locations of introduction of polar groups and the chargeability of resin particles.

[0076]

[Table 2]

Comparative Example 1 (Developer by Dispersing Pigment) 5 g of a phthalocyanine pigment (manufactured by Dainippon Seika Ltd .; cyanine blue 4938), 50 g of the protective colloid of Synthesis Example 5 and 200 g of Isopar M were mixed at 2000 rpm for 3 hours in an SG mill. It was a concentrated toner. 20 g of this was added to 700 g of Isopar M and diluted to obtain a negatively chargeable developer. The particles thus obtained had a particle diameter of 0.23 micron, and when the structure of the particles was observed with a transmission electron microscope, some pigments and resins were found to be scattered.

Comparative Example 2 (Developer by Pigment Dispersion ) 5 g of an azo pigment (manufactured by Dainippon Seika Ltd .; red 10), 50 g of the protective colloid of Synthesis Example 6 and 200 g of Isopar M were used.
A concentrated toner was obtained by mixing with an SG mill at 000 rpm for 3 hours. 20 g of this was added to 700 g of Isopar M and diluted to obtain a positively charged developer. The particles thus obtained had a particle size of 0.25 micron, and when the structure of the particles was observed with a transmission electron microscope, some pigments and resins were found to be scattered.

Comparative Example 3 (by mixing protective colloid and pigment
Developer) Except for the pigment, the protective colloid was prepared as in Synthetic Example 5 protective colloid 2
Negatively charged particles were synthesized in the same manner as in Example 1 except that the amount was changed to 0 g. The particle size of the obtained particles was 0.53 micron. 100 g of these particles, 5 g of cyanine blue 4938, 50 g of the protective colloid of Synthesis Example 5 and 200 g of Isopar M were mixed with an SG mill at 2000 rpm for 3 hours to give a concentrated toner. 20 g of this was added to 700 g of Isopar M and diluted to obtain a negatively chargeable developer. Observation with a transmission electron microscope revealed that some of the pigments and resin particles were scattered.

Comparative Example 4 (by mixing protective colloid and pigment
Developer) Except for the pigment, a protective colloid is prepared as in Synthetic Example 6 protective colloid 2
Positively charged particles were synthesized in the same manner as in Example 1 except that the amount was changed to 0 g. The particle size of the obtained particles was 0.49 micron. 100 g of the particles, 5 g of phthalocyanine blue, 50 g of the protective colloid of Synthesis Example 6 and 200 g of Isopar M were mixed at 2000 rpm for 3 hours in an SG mill to give a concentrated toner. 20 g of this was added to 700 g of Isopar M and diluted to obtain a positively charged developer. Observation with a transmission electron microscope revealed that some of the pigments and resin particles were scattered.

Comparative Example 5 (Developer by kneading → emulsification) Sorbitan tristearate was used as a protective colloid, and the pigment dispersant used in Synthesis Example 1 was used.
Emulsified in the same manner as. The operation of interfacial polymerization in the latter step was not performed. The particles obtained had a particle size of 5.7 microns. 20 g of these particles were added to 700 g of Isopar M and diluted to obtain a negatively chargeable developer. When observed with a transmission electron microscope, the pigment was almost present in the particles.

Comparative Example 6 (Developer by kneading → emulsification) Sorbitan tristearate was used as a protective colloid, and the pigment dispersant used in Synthesis Example 3 was used.
Emulsified in the same manner as. The operation of interfacial polymerization in the latter step was not performed. The particle size of the obtained particles was 6.3 microns. 20 g of these particles were added to 700 g of Isopar M and diluted to obtain a positively charged developing solution. When observed with a transmission electron microscope, the pigment was almost present in the particles.

<Evaluation Example 1 (Developer for wet copier)> The negatively chargeable liquid developers of Examples 2, 3, 5 and Comparative Examples 1, 3, 5 are commercially available copy machines (manufactured by Ricoh Co .; CT5085). Then, a printing test was conducted. Table 3 shows the results.

[0084]

[Table 3]

<Evaluation example 2 (developer for electrophotographic plate making)> A scanning exposure type plate making machine "1440EZ platesetter" (made by US Print Aware Co., Ltd.) using a semiconductor laser having a wavelength of 780 nm as a light source was used for the electrophotographic printing original plate. Examples 4, 6,
Images were formed by the operations of charging, exposure, liquid development and fixing using the positively chargeable liquid developers of Nos. 7 and 8 and Comparative Examples 2, 4 and 6. After that, using an alkaline developer (Printer for 1440EZ) manufactured by US Print Aware,
After removing the photosensitive layer on the non-image portion where the toner is not adhered, the protective layer was further protected with a gum solution to prepare a planographic printing plate in which the image of the toner remained as an image area.

Each of the obtained printing plates was used as a small offset printing machine Hamada Star 7000CD manufactured by Hamada Printing Machinery Co., Ltd.
Mounted on X and printed on wood free paper using a commercial ink.
The results are shown in Table 4.

[0087]

[Table 4]

As is clear from the results of Tables 3 and 4,
The liquid developers of the examples according to the present invention are less likely to cause toner sedimentation and can develop clear images. It can also be seen that dirt in the developing device is less likely to occur.

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Claims (9)

[Claims] 1. A liquid developer comprising a non-aqueous dispersion medium, in which pigment and / or dye are encapsulated, and colored resin particles microencapsulated by a resin insoluble in the dispersion medium are dispersed. 2. The resin insoluble in the dispersion medium is a polyurethane resin and / or a polyurea resin.
The liquid developer according to item 1. 3. The number average particle diameter of the colored resin particles is 0.
The liquid developer according to claim 1, which has a thickness of 05 to 1 μm. 4. The liquid developer according to claim 1, wherein the pigment and / or dye is contained in a state of being dispersed or dissolved by a pigment dispersant. 5. Interfacial polymerization of a compound having two or more active hydrogens and a compound having two or more functional groups capable of reacting with the active hydrogens in the presence of a pigment and / or a dye in a non-aqueous dispersion medium. A method for producing a liquid developer, characterized in that microcapsulated colored resin particles are produced by encapsulating the pigment and / or the dye. 6. A step of dispersing or dissolving a pigment and / or dye to be encapsulated in microcapsules and a pigment dispersant in a compound insoluble in the non-aqueous dispersion medium among the compounds for interfacial polymerization. In the presence of a protective colloid, a step of adding the non-aqueous dispersion medium to the dispersion liquid or the solution to perform dispersion emulsification, and a step of adding the other compound for interfacial polymerization to the dispersion emulsion to perform interfacial polymerization. The method for manufacturing a liquid developer according to claim 5, further comprising: 7. The compound having two or more active hydrogens is a compound having two or more amino groups and / or hydroxyl groups, and the compound having two or more reactive groups capable of reacting with the active hydrogens is an isocyanate group. The method for producing a liquid developer according to claim 5, wherein the compound has two or more compounds. 8. The method for producing a liquid developer according to claim 6, wherein a protective colloid in which a polar group for imparting an electric charge to the colored resin particles is introduced is used as the protective colloid. 9. The pigment dispersant in which a polar group for imparting an electric charge is introduced into colored resin particles is used as the pigment dispersant encapsulated in the microcapsules. A method for producing the liquid developer described.