JPS6118966A - Method for producing image-forming particles - Google Patents

Abstract

PURPOSE:To enhance fluidity and to stabilize triboelectric characteristics by forming at least one covering layer composed of a colorant or magnetic particles or a conductive agent, and a binder resin on core particles specified in particle diameter distribution. CONSTITUTION:The image forming particles are obtained by adding to a hydrophilic org. liquid in an amt. of 0.1-10wt% a polymer dispersant soluble in said liquid, adding at least one kind of vinyl monomer soluble in said liquid but when polymerized, swellable but almost insoluble in it, in an amt. of <=20 times the amt. of said polymer dispersant, polymerizing it to produce polymer particles having an average particle diameter of 1-100mum, and a component in a particle diameter distribution of within + or -25% weighing >=95% of the total weight of the particles, using them as the core particles, and coating each of them with at least one layer composed of a colorant, magnetic particles, or a conductive agent, and the binder resin.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a method for producing image-forming particles used for developing electrostatic images in electrophotography, electrostatic recording, electrostatic printing, and the like.

Prior Art Conventionally, image-forming particles, especially toners for developing electrostatic images, are
It is produced by melt-kneading a soft polymer and a colorant, dispersing the colorant in the polymer, and finely pulverizing the colorant-dispersed polymer.The fine powder obtained by this production method is Since the diameter distribution is very wide and further classification is required to obtain a toner that can be put to practical use, the manufacturing process is ultimately complicated and the cost is high. Another disadvantage was that the product particles had an amorphous shape, resulting in poor fluidity.

On the other hand, a production method using a polymerization method has been proposed as a method for directly producing colored polymer fine particles without a pulverization process (
For example, Special Publication No. 36-10231, No. 47-5183
No. 0, No. 51-14895, JP-A-53-17735
N, No. 53-17736 and No. 53-17737
(see issue).

These methods are based on the so-called suspension method, in which a polymerizable composition containing a polymerizable monomer, a polymerizable fungicide, and a colorant is suspended in an aqueous dispersion medium and polymerized. Direct 1-
It is a warning of the creation of a man.

This method has the advantage that the particles of the toner produced are spherical and have excellent fluidity, but the production process is simple and the particle size is small. It is difficult to make the distribution uniform, and it is impossible to make a functional tonneau with a coating layer.

Purpose The purpose of the present invention is to obtain image forming particles (It + shall be.

(14) In the present invention, a polymer dispersant that dissolves in the hydrophilic organic liquid is added to the hydrophilic organic liquid in a range of 0.1 to 10% by weight,
In addition, although it dissolves in the hydrophilic organic liquid, the number of polymers formed is determined to be wetted by the hydrophilic organic liquid.
One or more vinyl monomers that do not dissolve in water are added and polymerized in an amount of 20 times or less of the polymer dispersant, and the average particle size is 1 to 100 μm and the particle size distribution is kept within ±25%. Polymer particles having a particle size of 95% or more by weight are obtained, and these are used as core particles. This is a method for producing image forming particles characterized by forming at least one coating layer.

Note that the average particle diameter of the obtained particles is 1 to 100 fI
It is preferable that particles having a particle diameter of 1 and within ±30% of the particle size distribution account for 95% or more by weight.

Examples of the hydrophilic organic liquid used in the present invention include methyl alcohol, ethyl alcohol, denatured ethyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, tert-butyl alcohol, s
ea -butyl alcohol, tert-amyl alcohol, 3-pentatol, octyl alcohol, benzyl alcohol, cyclohexanol, furfuryl alcohol, tetrahydrofurfuryl alcohol, alcohols such as ethylene glycol, glycerin, diethylene glycol, methyl cellosolve, cellosolve, butyl cellosolve , isopropyl cellosolve, butyl cellosolve, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethyl glycol 7-methyl ether, diethylene glycol monoethyl ether, and other ether alcohols.

These organic liquids can be used alone or in a mixture of two or more. In addition, when organic liquids other than alcohols and ether alcohols are used in combination with the above-mentioned alcohols and ether alcohols, various SP values can be obtained under conditions that do not impart solubility to the polymer particles produced in the organic liquid. It is possible to adjust the average particle size and particle size distribution of the produced polymer particles by changing the . These a
Examples of organic liquids used include hydrocarbons such as hexane, octane, petroleum ether, cyclohexane, benzene, toluene, and xylene, halogenated hydrocarbons such as carbon tetrachloride, trichlorethylene, and tetrabromoethane, ethyl ether, and dimethyl. Glycol, trioxane, ethers such as tetrahydrofuran, acetals such as methylal, diethyl acetal, ketones such as acetone, methylethylkene, methylisobutylkene, cyclohexane, butyl formate, butyl acetate, ethyl propionate, cellosolve Esters such as acetate, formic acid,
Also included are acids such as acetic acid and propionic acid, sulfur and nitrogen-containing organic compounds such as nitropropene, nitrobenzene, dimethylamine, monoethanolamine, pyridine, dimethylsulfoxide, and dimethylformamide, and their fine ice.

5042-1 in the above solvent mainly composed of hydrophilic organic liquid.
NO2'', PO43-1C1-1Na+, K+, Mg2
The polymerization may be carried out in the presence of +, Ca2+, and other inorganic ions.

Furthermore, by changing the type and composition of the mixed solvent at the start of polymerization, during polymerization, and at the end of polymerization, the average particle size, particle size distribution, drying conditions, etc. of the produced polymer particles can be adjusted.

Suitable examples of dispersion stabilizers include acids such as acrylic acid, methacrylic acid, α-cyanoacrylic acid, α-cyanomethacrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic acid or maleic anhydride, or water. Acrylic monomers containing MW, such as β-hydroxyethyl acrylate, β-hydroxyethyl methacrylate, β-hydroxypropyl acrylate, β-hydroxypropyl methacrylate, γ-hydroxypropyl acrylate,
γ-hydroxypropyl methacrylate, 3-acrylic acid
Chloro-2-hydroxypropyl, methacrylic-derived 3-chloro-2-hydroxypropyl, diethylene glycol heptanoacrylate, diethylene glycol monomethacrylate, glycerin heptanoacrylate, glycerin monomethacrylate, N-medium Vinyl alcohol or ethers with vinyl alcohol, such as vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, etc., such as roll acrylamide and N-methylol methacrylamide, or esters of vinyl alcohol and compounds containing a carboxyl group, such as acetic acid. Vinyl, vinyl propionate, vinyl butyrate, etc.
Nitrogen atoms such as acrylamide, methacrylamide, diacene acrylamide or their methylol compounds, acid chlorides such as acrylic acid chloride and methacrylic acid chloride, vinylpyridine, vinylpyrrolidone, vinylimidazole, and ethyleneimine, or their heterocycles. Homopolymers or copolymers such as those having, polyoxyethylene, polyoxypropylene, polyoxyethylene alkylamine, polyoxypropylene algylamine, polyoxyethylene alkylamine, polyoxypropylene alkylamide, polyoxyethylene nonylphenyl ether, Polyoxyethylene groups such as polyoxyethylene lauryl phenyl ether, polyoxyethylene stearyl phenyl ester, and polyoxyprolene-nilphenyl ester, leruloses such as methyllerulose, hydroxyethyl cellulose, and hydroxypropyl cellulose, and the above-mentioned hydrophilic Copolymers such as those having a benzene nucleus or derivatives thereof such as styrene, styrene, α-methylstyrene, and vinyltoluene, or acrylic acid or methacrylic resistant derivatives such as acrylonitrile, allyl methacrylate, and acrylamide, and crosslinked 1 Any copolymer of the F monomer such as ethylene glycol dimethacrylate, dielene glycol dimethacrylate, allyl methacrylate, divinylbenzene, etc. can be used.

These polymer compound dispersants may be appropriately selected depending on the hydrophilic organic liquid used and the type of target polymer particles. High affinity and adsorption to the surface of polymer particles,
In addition, those having a hydrophilicity of 1 to 1 and an affinity for organic liquids of 1j1 and high solubility are selected. In addition, in order to increase the repulsion between particles sterically, those with a certain degree of molecular chain strength, preferably those with a molecular weight of 10,000 or more, are selected. However, if the molecular weight is too high, the liquid viscosity will increase significantly. Care must be taken because the process becomes difficult, resulting in poor operability and stirring performance, and variations in the probability of precipitation of the produced polymer on the particle surface.

Furthermore, it is also effective for particle stabilization to allow some of the monomers of the above-mentioned polymer compound dispersant to coexist with the monomers constituting the desired polymer particles.

In addition, these polymer compound dispersants and a) metals such as cobalt, iron, nickel, aluminum, copper, tin, lead, magnesium, etc. or their alloys (especially preferably 1μ or less), iron oxide, copper oxide, Inorganic compound fine powder of oxides such as nickel oxide, zinc oxide, titanium oxide, silicon oxide, etc.
carbon black, nigrosine dye, aniline blue,
Pigments such as chrome yellow, fucrocyanine blue, rose bengal, dyes, higher alcohol sulfate ester salts, alkylbenzene sulfonates, α-olefin sulfonates, anionic surfactants such as phosphate esters, alkyl amine salts, amino acids Alcohol fatty acid derivatives, polyamine fatty acid derivatives, amine salt types such as imidacillin,
Alkyltrimethylammonium salts, sialgyldimethylammonium salts, alkyldimethylbenzylammonium salts, pyridium salts, alkylisoquinolinium salts,
Cationic surfactants of the quaternary ammonium salt type such as benzethonium chloride, nonionic surfactants such as fatty acid amide derivatives, polyhydric alcohol derivatives, etc., such as alanine type [e.g. alkylaminopropionic acid], glycine type [e.g. Even when an amino acid type or betaine type amphoteric surfactant such as [ethyl)glycine, di(octylaminoethyl)glycine] is used in combination, the stabilization of the produced polymer particles and the improvement of the particle size distribution can be further enhanced.

Generally, the amount of the polymer dispersant used varies depending on the type of polymerizable monomer for forming the desired polymer particles, but it is preferably 0.1% to 10% by weight, more preferably 1% by weight, based on the hydrophilic organic liquid. % to 5% by weight is preferred. When the concentration of the polymer dispersion stabilizer is low, relatively large diameter polymer particles are obtained, and when the concentration is high, small particles are obtained, but even if the concentration exceeds 10% by weight, It has little effect on reducing the diameter.

The generated polymer particles are stabilized by a polymer dispersion stabilizer distributed in a hydrophilic organic liquid and on the polymer particle surface in equilibrium, and the particle size distribution of the generated polymer is stabilized by polymer dispersion. There is a close relationship between the amount of monomer added and the amount of monomer added.
More preferably, polymer particles with a narrow particle size distribution can be obtained only when an amount of 10 times or less is used.

In the present invention, the vinyl monomer is one that is soluble in a hydrophilic organic liquid, such as styrene, 0-methylstyrene, 01-methylstyrene, p-methylstyrene, α-methylstyrene, p-ethyl Styrene, 2.4-
Dimethylstyrene, p-n-butylstyrene, p-te
rt-butylstyrene, p-n-hexylstyrene, p
-n-octylstyrene, p-0-nonylstyrene, p
-n-decylstyrene, p-n-dodecylstyrene, p
- Styrenes such as methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, acrylic acid n-octyl, dodecyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, methyl α-chloroacrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate , n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, etc. α-methylene aliphatic monocarboxylic acid esters, acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile, and acrylamide, vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide, and vinyl fluoride, etc. It means a mixture of A and D or each other, and a mixture of these and 1lff1 which contains 50% by weight or more and can be copolymerized with these.

Further, the polymer in the present invention may be polymerized in the presence of a so-called crosslinking agent having two or more polymerizable double bonds to form a crosslinked polymer.

Preferably used crosslinking agents include divinylbenzene,
Divinylnaphthalene and aromatic divinyl compounds that are derivatives thereof, their ethylene glycol dimethacrylate-1~, diethylene glycol methacrylate-1~, 1~
Liedylene glycol methacrylate! Diethylene 1/4H such as helimethylolpropane triacrylate, allyl methacrylate, tert-butylaminoethyl methacrylate, tetraethylene glycol dimethacrylate, 1,3-butanediol dimethacrylate
7]) All divinyl compounds such as levonic acid ester, N,N-divinylaniline, divinyl ether, divinyl sulfide, divinyl sulfone, and compounds having three or more vinyl groups can be used alone or in mixtures.

The polymerization initiator for the monomers used is, for example, 2
, 2'-7zobisisobutyroni-1helyl, azo polymerization initiators such as 2,2-azobis(2,4-dimethylvaleronitrile), lauryl peroxide, benzoyl peroxide, tert-butylperoct A peroxide polymerization initiator such as A-1, a common compound initiator such as potassium persulfate, or a combination thereof with sodium thiosulfate, an amine, etc. are used.

Polymerization initiator concentration is 0 per 100 parts by weight of vinyl monomer.
．． 1 to 10 parts by weight is preferred.

Usually, as for polymerization conditions, the concentration and blending ratio of the polymer dispersant and vinyl monomer in the hydrophilic organic liquid are determined in accordance with the target, average particle diameter, and target particle diameter distribution of the copolymer particles.

If the average particle size is to be made small, the concentration of the polymeric dispersant is set high, and if the average particle size is to be made large, the concentration of the polymeric dispersant is set to be low.

On the other hand, if the particle size distribution is to be very sharp, the vinyl monomer concentration is set low, and if a relatively wide distribution is acceptable, the vinyl monomer concentration is set high, but in general, polymer dispersion If the stabilizer is used in an amount exceeding 20 times the amount used, it is difficult to obtain particles having a particle diameter within ±25% of the average particle diameter with a weight distribution of 95% or more.

After completely dissolving the polymer dispersion stabilizer in the hydrophilic organic liquid, one or more vinyl monomers, a polymerization initiator,
If necessary, inorganic fine powders, surfactants, dyes, and pigments are added, and polymerization is carried out by heating with usual stirring (50 to 300 rpm), preferably in an inert gas stream.

A polymerization time of 5 to 40 hours is required to carry out polymerization in a high polymerization rate range, but it is possible to stop the polymerization when the desired particle size and particle size distribution is achieved, or to add a polymerization initiator sequentially. You can increase the speed.

In addition, vinyl monomers can be added periodically during polymerization or as appropriate after completion of polymerization to adjust the physical and chemical properties of the copolymer, increase the average particle size, and adjust the particle size distribution to suit the purpose. can.

For example, by periodically adding vinyl monomers with different types and blending ratios during polymerization, it is possible to synthesize polymer particles with different physical properties from the center of the polymer particles outward. . Furthermore, if a dye, pigment, etc. are present at the interface, the polymer particles can be colored and the colorant can be immobilized.

In addition, the vinyl monomer is polymerized again under appropriate conditions using the polymer particles that have completed polymerization as cores,
Particle growth can be avoided by precipitating the newly synthesized polymer on the surface of the core polymer. The vinyl monomer used in this case may be the same as the core particle, or if a different type of vinyl monomer is selected, it is possible to synthesize spherical polymer particles coated with a different type of polymer compound. It is possible.

After the polymerization is completed, the polymer slurry is recovered and washed by operations such as sedimentation, centrifugation, and decantation, and then completely spherical polymer particles with a uniform particle size distribution are made into powder by filtration, spray drying, etc. Obtainable.

As a technique for forming a coating layer on the surface of the above-mentioned core particles,
Examples include (1) fluidized bed coating, (2) spray dryer coating, and (3) liquid phase coating such as suspension dispersion.

The coating liquid is a mixed suspension consisting of a colorant, magnetic powder, or conductive agent, a binder (including a latex solution), and water or a solvent. A solvent is selected that does not dissolve the above-mentioned core particles (it is better to use a solvent that slightly dissolves the surface of the core), and water is used when forming a latex solution. Examples of latex solutions include polystyrene, polyethylene, acrylic resins, and copolymers thereof.

Examples of the coloring agent used in this invention include the following Mj-rich dyes.

Black pigment carbon black, Allege 1 non-black, lamp black, aniline black.

Yellow pigment yellow lead, zinc yellow, cadmium yellow, yellow iron oxide, mineral fas 1 to yellow, nickel titanium yellow, nabels yellow, naphthol yellow 81 Hansa Yellow G, Hansa Yellow 10G1 Benzidine Yellow G1 Benzidine Yellow GR, Quinoline Yellow Rake, Permanent Screw 1 to Yellow NCG.

Tarl ~ Razinregi.

Orange pigment red yellow lead, molybdenum orange, permanent orange GTR, pyrazolone orange, palkan orange, indanthrene brilliant 1 to orange RK, benzidine orange G1 indanthrene brilliant orange GK.

Red pigment red pigment, cadmium red, for buttons, mercury cadmium sulfide, permanent red 4R.

Lysol Red, Pyrazolone Red, Watching Red Calcium Salt, Lake Red D, Brilliant Cardin 6B, Eosin 1 Norki, Rhodamine Lake B1 Alizarin Lake, Brilliant Carmine 3B0 Purple Pigment Manganese Purple, Fast Violet 1-B1 Methyl Violet Lake.

Blue pigments navy blue, Kobal 1 to blue, alkali blue lake, Victoria blue lake, phthalocyanine blue, metal-free phthalocyanine blue, phthalocyanine blue partially chlorinated product, first sky blue, indanthremble-B
O2 Green pigment chrome green, chromium oxide, pigment green B1
Malachite Green Lake, Fanal Yellow Green.

white pigment Zinc white, titanium oxide, antimony white, zinc sulfide.

Extender pigments Palite powder, barium carbonate, clay, silica, white carbon, tarri, alumina white 1, various dyes 1 (basic, acidic dispersion, direct dyes 1'31, etc.) Nigrosine, medilene blue, rose bengal, Quinoline Yellow, Tal], Raman Blue, etc.

The magnetic powder used in this invention may be any acidic, neutral, or basic magnetic material, but when present during monomer polymerization, Il+-1 is 6 or more, preferably ρ1-1 is 8.
~10 magnetic materials are good.

Furthermore, it is a substance that is strongly magnetized in the direction of a magnetic field, is preferably black in color, is well dispersed in resin, is chemically stable, and can be easily obtained in the form of fine particles with a particle size of 1 μ or less. is desirable, so magnetite (triiron tetroxide) is most preferred. Typical magnetic or magnetizable materials include metals such as cobalt, iron, and nickel;
aluminum,] baltic, copper, iron, lead, magnesium,
Alloys and mixtures of metals such as nickel, tin, zinc, antimony, beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, vanadium; aluminum oxide, iron oxide, copper oxide,
Metal compounds including metal oxides such as nickel oxide, zinc oxide, titanium oxide and magnesium oxide; refractory nitrides such as nitride 1 hvanadium and chromium nitride; carbides such as tungsten carbide A3 and silicon carbide. ; Ferrite and mixtures thereof can be used.

These ferromagnetic materials preferably have an average particle size of about 0.1 to 1 μm, and the amount contained in the toner is about 100% of the resin component.
The amount is preferably about 50 to 300 parts by weight based on the market weight, particularly preferably 8 parts by weight based on 100 parts by weight of the resin component.
It is 0 to 200 parts by weight.

Examples of the conductive agent include, in addition to carbon black, inorganic materials such as copper iodide and ruthenium oxide, various metal powders, and conductive polymer substances such as polyacetylene, polypyrrole, and polythenylene.

Furthermore, in the developer of this invention, it has been confirmed that the transfer efficiency is better when the magnetic toner is triboelectrically charged to the opposite polarity to the polarity applied to the transfer recording paper in the electrostatic transfer process. , monoazo dyes, zinc hexadecylsuccine-1-, alkyl esters or alkylamides of naphthoic acid, nitrofumic acid, N,N--tetramethyldiaminebenzophenone, N,N--tetramethylbenzidine, triazine It is preferable to add a strongly polar substance, which is called a charge suppressor in this field, such as a metal complex of salicylic acid or the like.

As properties improving agents such as fluidity of the toner, it is also possible to add and mix, for example, silica, hard resin fine powder, zinc oxide, higher fatty acids, higher fatty acid metal salts, silicone oil, fluorine oil, and the like.

Each of the above materials is appropriately selected and mixed.There are various mixing methods such as a universal mixer, a homogenizer, etc. as a wet mixing method, but ball mill dispersion is currently the most stable and good method. You can get something.

The mixing ratio of the solvent, binder, colorant, etc. is selected depending on the application and is generally within the following range.

Solvent: 50-200 Weight: 10-50 n Colorant, etc.: 1-5 Q n The thickness of the coating layer formed using the coating liquid is 0.1
The thickness is about 5 μm, and if necessary, it has a multilayer structure of two or more layers.

Next, examples will be described.

Example 1 Methanol 3 dried with molecular sieve 5A was placed in a 500 cc Mitsuro flask equipped with a stirring blade and a cooling tube.
Add 20g of polyacrylic acid (average molecular weight 250,000) 4
．． 8 was added little by little while stirring until it was completely dissolved. In addition, methyltrioctylammonium chloride 1
．． 00. Added hydrophobic colloidal silica i,og,
Methyl methacrylate 480.2.2'-Azobisisobutylene Onitrile 0.29 was added, and the inside of the flask was purged with dry argon gas while stirring, and left for 1 hour with a small amount of gas flowing.

The mixture was stirred at 1100 rpm in a constant temperature water bath at 60°C±0.1°C, and polymerization was started at 4T. 20 minutes after heating, the inside of the flask started to become cloudy, and then a solution of 2.2" tert-butanol containing 5% by weight of azohisisobutyronitrile was added.
．． The polymerization was completed after 8 hours, and the mixture was cooled.

Analysis by gas chromatography showed a polymerization rate of 99.5%. The resulting dispersion was stable, had no deposits on the flask, stirring blades, etc., passed through a 37 μm mesh, and left no residue.

The obtained dispersion was cooled and centrifuged at 200 rpm.
When centrifuged at 100 mL, the polymer particles were completely settled and the upper liquid was clear. Remove the supernatant and add 20 methanol
00 was added and the mixture was stirred and washed for 1 hour. Repeat the steps of centrifugation and washing with methanol, and finally wash with water.
Filtration was performed using a μm microfilter. The filtrate was clear, and it was confirmed that there were no particles smaller than 171.

The filtered product was air-dried for one day and one night, and then dried under reduced pressure at 50° C. for 24 hours to obtain white powdery polymer particles at a yield of 97%.

When observed using an optical microscope, the particles had a perfectly spherical shape and were highly transparent.

Observation with a scanning microscope shows that the average particle size is 5.2 μm, and the weight (or volume) is in the range from 3.9 μm to 6.5 μm.
A distribution of 98% was obtained.

2) Coating liquid! llll Created polystyrene latex solution (solid content 30%) 2
While stirring 00 parts, an aqueous dispersion of Fe 304 (uniformly dispersed 485 parts of RE30/300 parts of water by high-shear stirring) was added to prepare a stable and uniform aqueous dispersion containing magnetic powder.

3) Coating layer formation: Fluidized bed spray production particles ll as a coating device
/5pnay GranulatorMode13t
Using rea-1 (manufactured by Fuji Sangyo), 200 parts by weight of the above-mentioned nuclear particles were placed in it, air was blown out from the bottom,
Keeps the nuclear particles in a fluidized bed state. After that, while stirring the coating liquid, the inlet temperature is 1
Spray drying was carried out at a temperature of 40-160°C and an outlet temperature of 50-70°C.

In this way, spherical image-forming particles containing magnetic powder, having a coating layer with a thickness of 1 to 2 μm, and having an average particle size of 9 μm (particle size distribution within ±30%) were produced.

4) Image formation: Using the image forming particles thus produced as a developer, an electronic copying machine r R1copy FT-4700J is used.
(■ manufactured by Ricoh), a clear image was obtained.

Example 2 1) Production of core particles: 330 g of tert-butanol dried with a Molex cola sieve in a 500 cc three-sided flask equipped with a stirring blade and a cooling tube 5 g of ethylene glycol (100,000 molecules) Styrene-maleic anhydride copolymer 6.75g tricalcium phosphate 1.5g were added and stirred to dissolve.

66 g of styrene and 0.8 g of lauroyl peroxide were added to this, and the mixture was stirred and homogenized. The inside of the flask was purged with dry argon gas and allowed to stand for 1 hour with a small amount of gas flowing. 6
Polymerization was started in a constant temperature water bath at 10.1° C. while stirring at 150 rpm. After 20 minutes had passed after heating, the inside of the flask started to become cloudy and polymerization was continued for 15 hours. Even after 15 hours, a cloudy dispersion was formed, and the polymerization rate had reached 97%.

As in Example 1, centrifugation, methanol washing and stirring were repeated twice, and finally the product was washed with water and filtered through a 1 μm microfilter. The filtrate was clear and free of fine particles of 1 μm or less. .

130- The filtered product was air-dried overnight and then dried under reduced pressure at 50°C for 24 hours to obtain polystyrene beads with a yield of 96%.

According to observation using an optical microscope, all particles were perfectly spherical and had good transparency. Furthermore, according to a scanning electron microscope, the average particle diameter ranged from 12.3 μm to 19.2 μm to 15.4 μm.
The distribution contained 95% of particles up to μm in terms of volume.

2) Production of coating liquid: While stirring 200 parts of a commercially available polystyrene-PMMA copolymer latex solution (solid content 30%), a black carbon aqueous dispersion (6 parts of carbon/100 parts of water) was uniformly mixed by high shear stirring. A stable and uniform aqueous dispersion containing black carbon was prepared. While continuing this stirring, 40 parts of the core particles and water were added at appropriate times to adjust the pH.
>8, a uniform dispersion liquid was prepared in which particle aggregation and coalescence did not occur.

3) Formation of coating layer: While stirring this uniform aqueous dispersion, use a spray dryer (one nozzle type) to maintain an inlet temperature of 140 to 160°C.
, spray-dried at an outlet temperature of 50-10°C.

In this way, it has a coating layer with a thickness of 1 to 2 degrees Celsius containing black carbon, and has a spherical average particle size of 14 μ (particle size distribution ± 30%).
image-forming particles of (within) were produced.

4) Image formation: Using these image forming particles as a developer,
When images were formed using a Pro 1-type device based on a recording method called the LIST method described in No. 4995, clear images were obtained.

Example 3 1) Production of nuclear particles: Methanol 3 dried with molecular sieve 5A was placed in a 500 cc three-bottle flask equipped with a stirring blade and a chiller.
20o and 6.4L of polyvinylpyrrolidone (average molecular weight 40,000) was added little by little with stirring until completely dissolved.Additionally, 28.8g of styrene and 3.2L of Sn-butyl methacrylate (n-BMΔ) were added with stirring. 1, 2, 2-
-Azobisisobutyronitrile (AIBN) 0.2 (+
was added and completely dissolved. While stirring, purge the inside of the flask with dry argon gas, and while stirring,
It was left for 1 hour.

Polymerization was started while stirring at a stirring speed of 200 rpm in a constant temperature water bath at 60°C±0.1°C. The liquid began to become cloudy 15 minutes after hll, and remained a stable cloudy dispersion even after 20 hours of polymerization. It was confirmed by gas chromatography using ethylbenzene as an internal standard that the polymerization rate had reached 98%.

The obtained dispersion was cooled and centrifuged for 20 minutes in a centrifuge.
When centrifuged at 00 rpm, the polymer particles were completely settled and the upper liquid was clear. The supernatant liquid was removed, and 200 g of methanol was added to wash the solution with stirring for 1 hour. The operations of centrifugation and washing with methanol were repeated, and finally washing with water and filtration with a 1f1m microfilter.

The filtrate should be clear and free of any particles smaller than 1μ.
It was approved.

The filtered product was air-dried for one day and night, and then dried under reduced pressure at 50° C. for 24 hours to obtain white powder styrene-n-butyl methacrylate copolymer particles with a yield of 95%.

When observed under an optical microscope, the particles were completely pearl-shaped and highly transparent.

When observed using a scanning electron microscope, the average particle size was 4.8μ.
m from 3.6 μm to 6. (IHn particles had a distribution of 98% in terms of weight (or volume). 2) Production of coating liquid, 3) Formation of coating layer, and 4) Image formation were the same as in Example 1. Ta.

Example 4 1) Production of nuclear particles: 320 g of methanol dried with molecular sieve 5A in a 500 cc Mitsuro flask equipped with a stirring blade and a cooling tube.
and polyacrylic acid (molecular weight 250,000) 4.8 (l)
was added little by little with stirring until completely dissolved. In addition, 1.0 methyltrioctylammonium chloride
g, and 1.0 g of hydrophobic colloidal silica were added. Styrene 33°6g, n-butyl methacrylate 7.2 (1
12ethylhexyl acrylate-1-7.2 (1,2,2
=- Add 0.20 of azobisisobutyronitrile, and while stirring, purge the inside of the flask with dry argon gas,
It was left for 1 hour with a small amount of flow.

Polymerization was started in a constant temperature water bath at 60±0.1° C. while stirring at 1100 rpm. 20 minutes after heating, the inside of the flask started to become cloudy. Thereafter, a methanol solution containing 5% of 2-1-azobisisobutyroni-1-lyl was dissolved in 4. O
g at 2 hour intervals, and after 8 hours polymerization was completed and cold IJ was added.
It was. Analysis by gas chromatography shows 99.
The polymerization rate was 5%. The obtained dispersion was stable and had no deposits on the flask, stirring blades, etc.
It passed through all the meshes and there was no residue.

As in Example 3, centrifugation -1, methanol washing and stirring -2
After repeated washing with water and filtration with a 1 μm microfilter, the filtrate was clear.
It was confirmed that there were no fine particles smaller than 1 liter.

The filtered product was dried overnight and then dried under reduced pressure at 50°C for 24 hours to obtain a polymer powder of styrene/n-butyl methacrylate/2-ethylhexyl acrylate ternary copolymer with a yield of 97%. .

When observed using an optical microscope, the particles completely rejected the shape of a true sphere and were highly transparent.

When observed using a scanning electron microscope, the average particle size was 8.0μ.
Particles having a particle diameter of 6.0 μm to 10.0 μm were obtained with a distribution of 98% in terms of volume.

2) Production of coating liquid, 3) Formation of coating layer, and 4) Formation of image were the same as in Example 2.

Effects According to the present invention, while having the characteristics of conventional image forming particles such as electrostatic charge developing particles 1 to 1 toner, they have excellent fluidity due to their nearly spherical shape, stable charge characteristics, and excellent functionality. You can get something with improved properties.

Patent Applicant Ri Co., Ltd.] - Agent Patent Attorney Hidetake Komatsu Agent Patent Attorney Hiroshi Asahi Proceedings (written on his own initiative) August 30, 1980 Commissioner of the Japan Patent Office Manabu Shiga 1, Indication of Case Patent Application Showa 5959-139l17,
Relationship with invention title case Patent application Person name
(674) Rico Co., Ltd.-4, Agent
107 (phone number 586-8854) 5. Date of amendment order
(Voluntary) 6. In the specification to be amended (m), column 7 for claims and detailed explanation of the invention, the contents of the amendment are as shown in the attached sheet (attached sheet) (1) Patents from line 4 on page 1 of the description The scope of claims is amended as follows.

"2. Claims A polymeric dispersant that is soluble in the hydrophilic organic liquid is added to the hydrophilic organic liquid in an amount of 0.1 to 10% by weight; However, the resulting polymer is either swollen or barely soluble in the hydrophilic organic liquid.
The seed or two or more types of vinyl monomers are added to the polymer dispersant for a period of less than 100% to polymerize, and the average particle size is 1 to 100.
μm and particle size distribution ±2! ) Polymer particles whose weight ratio is 0.5% or more are particles with a particle size within 1%.
q1 Use this as a core particle, and 2) at least a coloring agent or magnetic particles or a conductive agent and a binder 1y,
1. A method for producing image-forming particles, which comprises forming at least one coating layer consisting of: ” (2) “2” on page 4, line 5, page 13, line 6, and page 17, line 10
Correct "0" to "50 (rjJ).

(3) WJ the "10 times amount" on page 13, line 7, as "20 times amount".

Claims (1)

[Claims] A polymeric dispersant that is soluble in the hydrophilic organic liquid is added to the hydrophilic organic liquid in an amount of 0.1 to 10% by weight. , the resulting polymer is swollen in the hydrophilic organic liquid, or polymerized by adding one or more vinyl monomers that are hardly soluble in an amount of 20 times or less relative to the polymer dispersant, Polymer particles having an average particle size of 1 to 100 μm and a particle size suppressed within ±25% of the particle size distribution account for 95% or more by weight are obtained, and these are used as core particles, and then A method for producing image-forming particles, which comprises forming at least one coating layer comprising at least a colorant, magnetic particles, a conductive agent, and a binder.