JPH02105162A - Production of microcapsule toner - Google Patents

Abstract

PURPOSE:To improve a preservable property and durability together with fixability by adding resin particles electrified to a positive polarity into an aq. dispersion of suspension-granulated particles coated with a negative polarity dispersant to further coat the particles with the resin. CONSTITUTION:The resin compsn. which is electrified to the positive polarity is suspension-granulated in the aq. medium in the presence of the negative polarity dispersant to form the suspension-granulated particles coated with the negative polarity dispersant. The resin particles which are electrified to the positive polarity are charged into the aq. dispersion of the suspension- granulated particles to coat the suspension-granulated particles with the resin particles. The microcapsule toner which obviated the generation of the incomplete films, prevents the shell material from being broken even by the physical and mechanical forces form the outside and the does not generate the composite particles is, therefore, obtd. The good fixability is obtd. in this way on ordinary paper and the microcapsule toner which is excellent in both the durability and long-term preservability against repetitive copying is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a toner used in electrophotography, electrostatic printing, magnetic recording, etc., and particularly relates to a method for producing a microcapsule type toner.

[Prior Art 1] Toner that visualizes electrical or magnetic latent images is used in various processes for forming and recording images.

In recent years, electrophotographic application technology has become more versatile.

2. Description of the Related Art Many technological developments have been made regarding toners or developers for forming copied images in accordance with the purpose. Toner is a powder that forms images, but in order to form images accurately, toner particles must have many functions, such as charging properties, transportability, fixing properties, and storage stability. . Generally speaking, there is no single substance that satisfies all of these requirements, so toners are usually prepared as a mixture of various materials. In a general toner manufacturing method, a binder resin is used to fix the toner on the transfer material, various coloring agents are used to give the toner its color, a charged ft1l agent is used to impart charge to the particles, and JP-A-54 -4214
In so-called one-component development methods such as those disclosed in Japanese Patent Application Laid-Open No. 55-IH5111, various magnetic materials are used to impart transport properties to the toner itself.

When manufacturing toner, in addition to these materials, a mold release agent and a flow stoppering agent are dry-mixed as necessary, and then uniformly mixed while applying temperature using a general-purpose mixing device such as a roll mill or extruder. After kneading and cooling, it is pulverized using various types of pulverizing equipment such as speed mills and jet mills, and O
By performing classification using various wind classifiers such as 9 classifier and MS classifier, the particle size can be adjusted to the size required for toner. The toner particles obtained in this way are dry mixed with a fluidizing agent, a lubricant, etc. as necessary, and also a so-called 23 &
When used in a partial development method, it is mixed with various magnetic carriers and then used as a toner for image formation.

However, in a toner made of a mixture of various materials having various functions, each function cannot fully exert its function separately.

Even if materials have 41 functions that are sufficient if they are separated into individual materials, they may be mixed together, or due to the particle form of toner, or other properties that make a material with a certain function undesirable as toner particles. For example, even if there is a binder resin that has very good fixing properties, the resin has moisture adsorption properties. Even if there is a magnetic material with excellent magnetic properties, if the compatibility between the magnetic material and the binder resin is poor, the magnetic material will be degraded during pulverization after kneading. In some cases, the toner particles become loose and the charging characteristics become unstable, or when a GL material is added to the toner material in an attempt to prevent the offset phenomenon to the fixing roller, the toner particles become non-uniform and the charging characteristics also become non-uniform. Sometimes it happens. Furthermore, binding materials that have very good fixing properties also have general properties such as problems with storage stability and durability during repeated use.

As a means to solve such problems, toner particles in the form of so-called microcapsule toner, as seen in U.S. Pat. No. 4,0111,099, U.S. Pat. is considered. In other words, it is a so-called function-separated toner that fully exhibits the functions of various materials and has sufficient performance as toner particles6. Something like this can be mentioned. In other words, the particles are a mixture of a binder resin that has good fixing properties but poor storage stability and durability, and a magnetic material that has good magnetic properties but tends to inhibit the charging properties of the toner. It is used as a material to give toner fixing and transport properties. Then, an outer wall is formed that encloses the mixture particles, and this outer wall, the so-called shell material, has a charging function and a core material protection function, and since the core material is further protected by the harder outer wall, it is durable. It is a form that has excellent storage stability.

Many proposals have been made regarding materials and manufacturing methods for such microcapsule toners.For example, in terms of composition, any material can be used within a general range.

There are many methods for obtaining microcapsules, including spray drying, interfacial polymerization, coacervation, phase separation, and 1n-situ polymerization.

However, it is not necessarily possible to produce a microcapsule toner having the necessary performance as a toner by the above-described method using materials having various desirable functions.

In other words, in many cases, the formation of the outer wall is incomplete, that is, a defective film occurs, and even if a shell forms, it easily peels off due to physical or mechanical force, or when making microcapsule toner, particles This causes a problem in that the toner particles coalesce and the toner becomes undesirable. Furthermore, there are many cases where materials that are useful for functioning as a normal toner are not necessarily suitable for producing microcapsule toners.

Most microcapsule toners are intended to be so-called pressure fixable toners.

This pressure fixing method is different from conventional fixing methods that use heat chambers or heated rolls, and is a method in which toner particles are attached to the transfer material using mechanical pressure. advantageous in terms of Furthermore, when using microcapsule toner, a softer material can be used as the fixing material compared to conventional bare pressure fixing toner, so the fixing pressure can be lower than before, which has the advantage that the fixing device can also be made smaller. . However, if there is imperfection in the formation of the outer shell as described above, the core material is soft and is exposed to the outer surface of the toner, or the core material that has flowed out may damage the developing sleeve or latent image carrier, which is the toner carrier. A so-called fusion phenomenon may occur on the barrel photosensitive drum 1-, toner conveyance may deteriorate due to decreased fluidity, and uneven charging may cause fogging or decreased density. , toner durability and storage stability will be reduced, and if the same encapsulated particles coalesce, this mixture will be destroyed in the developing device and the destroyed portion will become a defective film. This may cause deterioration in toner applicability to the developing sleeve, reduction in charging performance, and non-uniformity. In addition, the presence of free shell material (free shell or free polymer) that is not covered by the core material reduces the fluidity of the toner, and causes density reduction and image unevenness due to unnecessary band ML heavy charge accumulation and uneven distribution. Sometimes.

In addition, materials with sufficient strength and charging ability or a combination of two or more materials may be used as the outer wall of the capsule toner.
It is not suitable for producing a satisfactory microcapsule toner, and may result in an incomplete microcapsule toner as described above.

In addition, in -component magnetic toner, since the magnetic material that serves as the toner carrier is contained inside the toner particles, the content, distribution, uneven distribution, etc. of the magnetic material particles in each toner particle when finely divided affect the toner performance. For example, if the content of magnetic particles contained in each toner particle is different, the development characteristics of each toner particle will be different, which tends to cause phenomena such as fog on the image, and it is difficult to continuously develop the image. Alternatively, the change in image density during copying becomes large, resulting in significant deterioration in image quality. In addition, the fixing performance becomes inconsistent, and the toner coating on the sleeve roller for development tends to become muddy.Furthermore, because some toner particles have a high resin content and some toner particles have a low resin content, the fixing performance becomes inconsistent. or the offset property becomes worse. In addition, if the magnetic particles are not uniformly dispersed in the toner particles, the concentration of the toner particles will decrease, and the toner will tend to adhere to the developer sleeve roller, photoreceptor, cleaner, etc., and the toner will be blocked. The phenomenon becomes more likely to occur.

[Problems to be Solved by the Invention] The objects of the present invention are to prevent the formation of incomplete films, to prevent the shell material from being destroyed by external physical and mechanical forces, and to prevent the formation of coalesced particles. It is an object of the present invention to provide a method for manufacturing microcapsule toner that does not require the following steps.

Still another object of the present invention is to, according to the intended use of the toner,
An object of the present invention is to provide a method for producing a microcapsule toner in which toner performance can be arbitrarily controlled.

[Means and effects for solving the problem] As a result of intensive research, the present inventor suspended and granulated a positively charged resin composition in an aqueous medium in the presence of a negatively polarized dispersant, thereby dissolving the negative electrode. After forming suspended granulated particles coated with a dispersant,
The method for producing a capsule toner as described above is characterized in that positively charged resin particles are introduced into an aqueous dispersion of the suspended granulated particles, and the suspended granulated particles are covered with the resin particles. The inventors have discovered that the object of the invention can be achieved, and have arrived at the present invention.

The present invention will be explained in more detail below. In the following description, "%" and "part" expressing quantitative ratios are based on weight unless otherwise specified.

As the positively charged resin that becomes the suspended granulated particles (hereinafter referred to as core particles) used in the present invention, there are, for example, resins made of the following polymerizable monomers.

That is, for example, styrene, 0-methylstyrene,
-Methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, p-ethylstyrene, 2
．． 4-dimethylstyrene, p-n-butylstyrene,
Styrene and its derivatives such as p-tert-butylstyrene, p-n-hegylstyrene, p-n-octylstyrene, p-n-7nylstyrene, p-n-tethylstyrene, p-n-dodecylstyrene; ethylene ,
Ethylenically unsaturated monoolefins such as propylene, butylene, isobutylene; vinyl chloride, vinylidene chloride,
Vinyl halides such as vinyl bromide and vinyl conjugate; Vinyl esters such as vinyl acetate, vinyl propionate and vinyl benzoate: methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, methacrylic acid Isobutyl, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, acrylic Acrylic acid esters such as n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, and phenyl acrylate: vinyl methyl ether,
Vinyl ethers such as vinyl ethyl ether and vinyl imbutyl ether; Vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, and methyl isopropenyl ketone; Vinyl naphthalenes; Acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylaterile, and acrylamide. .

During polymerization, polymerization is carried out in the presence of the following crosslinking agent,
It may also be a crosslinked polymer.

divinylbenzene, divinylnaphthalene, divinyl ether, divinyl sulfone, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate)
, 1.3-butylene gelicoldimethacrylate, 1.
8 hexane glycol dimethacrylate, neopentyl glycol dimethacrylate, dipropylene glycol dimethacrylate, polypropylene glycol dimethacrylate), 2.2'bis(4-methacryloxyjethoxyphenyl)propane, 2.2'bis(4- Acryloxyjetoxyphenyl)propane, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, tetramethylolmethanetetraacrylate, dibromneopentyl glycol dimethacrylate, general crosslinking agents can be used as appropriate, and these polymerizable monomers Dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, vinylpyridine, dimethylaminomethylstyrene, vinylimidazole, etc. can also be copolymerized with the polymer.

In addition, low softening point compounds can also be used for the core material particles of the present invention. For example, paraffin wax (manufactured by Kuchimoto Sekiyu Co., Ltd.),
Paraffin wax (manufactured by Nippon Seiro), micro wax (manufactured by Nippon Oil), microcrystalline wax (manufactured by Nippon Seiro), hard paraffin wax (manufactured by Nippon Seiro), Polywax 500 (Petrolite), Polywax 8
55 (Petrolite), PH-130 (manufactured by Hoechst), Mitsui Hiwax IIQP (manufactured by Mikata Petrochemical),
Mitsui High Wax 220P (Mikata Petrochemical), Mitsui High Wax 81110P (Mikata Petrochemical), Mitsui High Wax 210P (Mikata Petrochemical), Mitsui High Wax 320P (Mikata Petrochemical), Mitsui High Wax 410P (manufactured by Mikata Petrochemical), Mitsui Hiwax 42
0P (manufactured by Mikata Petrochemical), Mitsui Hiwax 4202
E (Mikata Petrochemical), Highlets T-100X
(Mikata Petrochemical), Highlets? -200X (Mikata Petrochemical), Hi-Sea 2T-300X (Mikata Petrochemical); Vetrogin 80 (Mikata Petrochemical), Vetrogin 100 (Mikata Petrochemical), Vetrogin 120 (Mikata Petrochemical) Chemical), Tac Ace A-100 (Mikata Petrochemical), Tac Ace F-100 (Mikata Petrochemical),
Tac Ace a-eo (manufactured by Mikata Petrochemical), modified wax JC-1141 (manufactured by Mikata Petrochemical), modified wax JC-2130 (manufactured by Mikata Petrochemical), modified wax J
C-4020 (Mikata Petrochemical), modified wax JC-
1142 (Mikata Petrochemical), modified wax JC-50
20 (Mikata Petrochemical): Beeswax, carnauba wax,
Examples include montan wax and the like. In addition, in order to charge the battery to a positive polarity, cationic surfactants such as dodecyltrimethylammonium salt, Duomin T
(manufactured by Lion Akzo Co., Ltd.), dimethylaminoethyl (meth)acrylate (co)polymer, and diethylaminoethyl (meth)acrylate (co)polymer can be mixed and added.

The core material particles of the present invention can contain a magnetic substance, a pigment, a coloring agent such as carbon black, etc. For example, as the magnetic powder used with the above core material resin, fine powders such as various ferrites, hematites, magnetites, etc. is used. Especially 0. Preferably, these magnetic fine powders have a particle size in the range of O1 to O2. Although this is preferred, the surface may be hydrophobized using a titanium coupling agent, a silane coupling agent, a fatty acid, or the like.

In addition to the magnetic powder described above, carbon black, various dyes and pigments, hydrophobic colloidal silica, etc. may be added to or mixed with the core material particles of the present invention for the purpose of charge control, fluidity imparting, coloring, etc. can.

Examples of the negative dispersant used in the present invention include colloidal silica and bentonite.

In the present invention, positively charged resin particles used to coat the surface of core material particles (hereinafter referred to as wall material particles)
For the production of , emulsion polymerization method, emulsion polymerization method without using emulsifier,
Wall material particles can also be obtained by so-called soap-free emulsion polymerization.

Further, methods for positively charging the wall material particles in water include, for example, a method of introducing in advance a component that becomes positively polarized in an aqueous medium as a binder resin or a polymerizable monomer polymerization initiator, and a method of charging the wall material particles to positive polarity in water. Examples include a method of attaching or adsorbing a substance exhibiting positive polarity to the surface of the core particle after production by the above production method, or a method of using a combination of the above three, which are considered preferable in consideration of the production process. Any method can be used accordingly.

Further, as the binder resin of the wall material particles of the present invention, known resins can be used, and these resins are generally polymerizable monomers used in suspension polymerization, emulsion polymerization, soap-free polymerization, etc. For example, styrene, 0-methylstyrene, intestinal-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3 .4
-dichlorostyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-n-butylstyrene, p-jer
t-butylstyrene, p-n-hexylstyrene, p-
n-octylstyrene, p-n-7nylstyrene, p-
n-decylstyrene, p-n-dodecylstyrene, p-
Styrene and its derivatives such as chloromethylstyrene and -chloromethylstyrene; Ethylenically unsaturated monoolefins such as ethylene, propylene, butylene, and isobutylene; Vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide, and conjugated vinyl Vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate; Methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, methacrylate α-methylene aliphatic monocarboxylic acid esters such as m-2-ethylhexyl, stearyl methacrylate, phenyl methacrylate; methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, acrylic acid n
- Acrylic acid esters such as octyl, dodecyl acrylate, acrylic@2-ethylhexyl, stearyl acrylate, 2-chloroethyl acrylate, and phenyl acrylate; Vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, and vinyl isobutyl ether;
Vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, and methyl isopropenyl ketone; N-vinyl compounds such as N-vinyl pyrrole, N-vinyl carbazole, N-vinylindole, and N-vinyl pyrrolidone;
Vinylnaphthalenes include acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile, and acrylamide.

During polymerization, polymerization is carried out in the presence of the following crosslinking agent,
It may also be a crosslinked polymer.

divinylbenzene, divinylnaphthalene, divinyl ether, divinyl sulfone, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate)
, 1.3-butylene gelicoldimethacrylate, 1.
6-hexane glycol dimethacrylate, neopentyl glycol dimethacrylate, dipropylene glycol dimethacrylate, polypropylene glycol dimethacrylate, 2.2'bis(4-methacryloxyjethoxyphenyl)propane, 2.2'bis(4-acryloxyjetoxyphenyl) (toxyphenyl)propane, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, tetramethylolmethanetetraacrylate, dibromneopentyl glycol dimethacrylate, allyl phthalate, 1,2-propylene glycol,
General crosslinking agents such as 1,3-butanediol can be used as appropriate.

In addition, examples of monomer components that make the wall material particles have positive polarity in an aqueous medium include dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate,
Vinylpyridine, vinylimidazole, dimethylaminomethylstyrene, etc. can be mentioned, and these polymerizable monomers can also contain methyl groups, ethyl groups,
It may be quaternized with a benzyl group or the like.

As the polymerization initiator used when polymerizing the wall material particles and/or core material particles of the present invention, for example, 1.1'-
Azobis (cyclohexane-1-carbonitrile),
2.2'-Azobisisobutyronitrile, 2.2'
-azobis(2,4-dimethylvaleronitrile),
2.2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), dimethyl 2.2'-azobisisobutyrate, benzoyl peroxide, lauroyl peroxide.

2.2'-azobis(2-amidinopropane) 2k11
acid salt, 2.2'-azobis[2-(2-imidacillin-
2-yl)propane] dihydrochloride, 2,2'-azobis(
2-Methyl-N-El, 1-bis(hydroxymethyl)
-2-hydroxyethyl]propionamide), 2
．． 2'-azobis(2-methyleth[1,1'-bis(
hydroxymethyl)ethyl]propionamide),
Examples include 2.2'-azobis[2-methylto(2-hydroxyethyl)propionamide], 2.2'-azobis(isobutyramide) 2-elongate, and the like.

Two or more types of these polymerization initiators can be used in combination. The amount of the polymerization initiator used in the monomer composition is preferably 0.1 to 10.0 parts.

The wall material particles used in the present invention are used in an amount of 0.1 to 50 parts per 100 parts of the core material particles, more preferably 1 part
This is the case where ~30 parts are used. If the wall material particles are less than 0.1 part, the core material particles will not be encapsulated substantially, and if the wall material particles are 50 parts or more, the core material particles will significantly agglomerate with each other during encapsulation. It cannot be used practically as a toner.

In the present invention, the particle size ratio between the wall material particles and the core material particles may be between 1/1000 and 1/1, and more preferably between 11500 and 1/2, assuming that the particle size of the core particles is 1. This is the case between. If the particle size ratio of the wall material particles and the core material particles is smaller than 1/1000, that is, if the wall material particles are too small, a capsule wall may be formed on the surface of the core material particles, but microcapsules may be As a toner, the durability and storage stability are significantly inferior, and if the wall material particles are larger than 1/1, that is, the wall material particles are too large, even if the wall material particles can adhere to the surface of the core material particles, they will not be dense and strong capsules. It will not form a wall, which will also be significantly less durable.

The average particle diameter of the core material particles of the present invention may be in the range of 1 to 30 #L, and more preferably in the range of 5 to 20 #L.

When covering the core material particles of the present invention with wall material particles (hereinafter referred to as encapsulation), the pH of the aqueous medium must be controlled to promote dissociation of the negative polarity dispersant that coats the surface of the core material particles. is preferable, in which case the pH is 4 to 1
More preferably, the pH is adjusted to between 5 and 9. In this case, a buffer may be used to stabilize the pH.

In addition, during encapsulation, the temperature of the aqueous medium is 5℃ ~
It is sufficient that the temperature is between 98°C, and it is preferable that this temperature is set to be the same as or lower than the heat distortion temperature, glass transition temperature, melting point, etc. of the core material particles used for encapsulation.For example, if the core material particles are polymerized. When the resin composition is composed of a polymerized monomer, it is preferable to perform the encapsulation at a temperature of 90°C to 40°C, and when the resin composition is composed of a low softening point compound,
Preferably, the encapsulation is carried out at 0°C to 30°C.

[Example] Hereinafter, the present invention will be explained in more detail with reference to Examples.

Core material particles (1) After mixing and melting the components of the above recipe using an MKM mixer (manufactured by Koen Seisakusho), they were put into an attritor (manufactured by Mikata Miike Seisakusho) heated to 100°C, and mixed at 20 rpm for 1
Time dispersion was performed to obtain a molten mixture.

On the other hand, add 20 liters of water to a 20-ton horse mackerel mixer (special mechanical type).
40 g of silica (Aeroseal@300, manufactured by Nippon Aeroseal Co., Ltd.) was added as a dispersant and heated to 95° C. using a heating jacket to form a dispersion medium. 2 kg of the molten mixture obtained above was put into this dispersion medium, and the peripheral speed was 20 cm/2.
Granulation was performed by stirring for sec. After the granulation was completed, it was poured into cold water.

The mixture was classified using a wet classifier, further filtered, and redispersed in water to obtain a slurry containing 1O60% solid content.

This is the core material particle (1) of the present invention. When the surface of the core material particle was observed using an electron microscope, it was confirmed that the silica used for granulation remained. The average particle size was 10.4 #L.

Core material particles (2) The above resin composition and magnetic material are mixed, melt-kneaded using two rolls, and then coarsely pulverized, and then the coarsely pulverized product 1.0
kg'ItTK homomixer (manufactured by Tokushu Kika Kogyo) was placed in a 201 autoclave together with 15 Jl of water and 20 g of silica (Aerosil Cloud 300, manufactured by Nippon Aerosil Co., Ltd.) as an anionic dispersant. While stirring, the temperature inside the autoclave was heated to 170° C., and this temperature was maintained for 20 minutes. Next, the contents were cooled, and when the internal temperature reached 90°C, the contents were poured into ice water to form suspended granulated particles. ')Ta.

The mixture was further classified using a wet classifier, further filtered, and dispersed in water to obtain a slurry containing 15.0% solids. This was used as core material particle (2). When the surface of the core material particle was observed using an electron microscope, it was confirmed that the silica used for granulation remained. The volume average particle diameter measured by Coulter counter was 12.7 pm.

Core material particles (3) Using an attritor, the above polymerizable monomer mixture was
A monomer composition was prepared by mixing at °C.

Anionic fine powder colloidal silica (Aerosil 3)
00, manufactured by Nippon Aerosil Co., Ltd.) 10g was added to ion exchange water 1000cm2 as a liquid dispersion medium, and the mixture was heated at 200 rpm.
Volume 29. While stirring for 10 minutes at ■. The monomer composition prepared above was put into a stainless steel container, and the monomer composition was stirred at 60°C under N2 atmosphere for 30 minutes at 10.00 Orpm using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.). The body composition was granulated. After that, while stirring with a paddle stirrer,
The monomer composition was polymerized at 80° C. for 10 hours.

The mixture was further classified using a wet classifier, filtered, and redispersed in water to obtain a slurry containing 5.0% solids. These are referred to as core material particles (3).

When the surface of the core material particles was observed using an electron microscope, it was confirmed that the silica used for granulation remained. In addition, the volume average particle diameter measured by Coulter counter is 10.9
It was μmaro.

Wall material particles (1) The above polymerizable monomers were mixed to form a monomer composition of 2.0k.
g was prepared.

Add 50g of dodecyltrimethylammonium chloride as a surfactant to 15.0g of ion-exchanged water. Added to OJl and dissolved.

The monomer composition prepared above was charged into a stainless steel container with a capacity of 20 mm, and stirred at room temperature under an N2 atmosphere to obtain an emulsion. 212! While dropping 1.01 parts of ion-exchanged water in which 11.5 parts of acid Tl was dissolved, the temperature was raised to 50°C.

Thereafter, the reaction was carried out for 8 hours with stirring to polymerize the monomer composition. When the obtained fine particles were observed using an electron microscope, the average particle size was 0.1 liter.

This is referred to as wall material particles (1) of the present invention.

Wall material particles (2) Pour 131 liters of ion-exchanged water into a container with a capacity of 201, and add 2.0 parts of 2.2'-azobis[2-(2-imidacylin-2-yl)propane] dihydrochloride under acidic conditions with hydrochloric acid. was added and dissolved. Next, the mixture was heated to 60° C. under a N2 atmosphere, and 2.0 kg of the above polymerizable monomer mixture was added dropwise while stirring. Once the 0 dropwise addition was completed, stirring was continued for an additional 4 hours.

Next, the mixture was heated to 80° C. and stirred for 2 hours to complete the polymerization reaction. When the obtained fine particles were observed using an electron microscope, the average particle size was 0. It was n intestine.

This is referred to as wall material particles (2) of the present invention.

Wall material particles (3) Methyl methacrylate 90 parts L Dimethylamine ethyl methacrylate 10 parts Volume 20 fL
Put 131 liters of ion-exchanged water in a container, and add 131 ml of ion-exchanged water under acidic hydrochloric acid.
,2'-azobis(2-amidinopropane) dihydrochloride
1.0 part was added and dissolved. Then, under N2 atmosphere,
The mixture was heated to 0.degree. C. and added dropwise to the polymerizable monomer mixture 2 while stirring. When the addition was completed, stirring was continued for another 6 hours to complete the polymerization. When the obtained fine particles were observed using an electron microscope, the average particle size was 0.
．． It was 1 p■.

This is referred to as wall material particles (3) of the present invention.

Example 1 20 fL of slurry containing 1.0 kg of core material particles (1)
The p)I of the aqueous phase was adjusted so that the 0-order silica dissociated and acted as an anion.

A fine particle dispersion containing 150 g of wall material particles (3) was added to the suspension dispersion of the core material particles (1) with stirring. After continuing stirring for 1 hour, it was heated to 50°C and kept at that temperature for 2 hours.

After cooling to room temperature, it was separated from the oven and dried. When the surface of the particles was observed using an electron microscope, it was confirmed that the particles were covered with wall material particles.

This is referred to as the microcapsule toner (1) of the present invention.

Example 2 Example 1 except that a slurry containing 1.0 kg of core material particles (2) and a resin solution containing 200 g of wall material particles (1) were used.
The same operation as above was carried out to obtain the microcapsule toner (2) of the present invention.

Furthermore, when the surface of the particles was observed using an electron microscope,
It was confirmed that it was covered with wall material particles.

Example 3 Example 1 except that a slurry containing 1.0 kg of core material particles (1) and a resin solution containing 200 g of wall material particles (2) were used.
The same operation as above was carried out to obtain a microcapsule toner (3) with a completely finished tjl.

In addition, when the surface of the particle was observed using an electron microscope, it was found that
It was confirmed that it was covered with wall material particles.

Comparative Example 1 Core material particles (1) 1.0 kg and wall material particles (3) 15
0 g was taken out in a dry state and used to perform the high-speed air impact method (Material Technology, (4), 187 (1985)
) was used to perform encapsulation processing. This is referred to as comparative toner (1) of the present invention.

The microcapsule toner (1) of the present invention shown in Example 1
) and Comparative Toner (1) were mixed with hydrophobic silica fine powder, and then an image evaluation test was conducted on 1000 consecutive sheets using an FC-9 (manufactured by Canon) copying machine.

When the obtained images were observed, the microcapsule toner (1) of the present invention had a high image density and was clear with little fog, but compared to that, the image density of the comparative toner (1) was low from the beginning. As the durability test progressed, the fog decreased significantly and was clearly inferior.

In addition, when the microcapsule toner (1) of the present invention and the comparative toner (1) were left in an environment at a constant 45°C and a blocking test was conducted, it was found that the microcapsule toner (1)
No change was observed with the comparison toner (1).
), the fluidity decreased significantly.

Furthermore, when we investigated the relationship between fixing temperature and fixing performance using an experimental machine with an improved fixing device of FC Knee 5 and variable fixing temperature, we found that the microcapsule toner (1) of the present invention
showed sufficient fixing properties even at 100°C.

Comparative Example 2 A comparative toner (2) was obtained in the same manner as Comparative Example 1 except that core material particles (2) and wall material particles (1) were used.

Microcapsule toner (2) of the present invention shown in Example 2
) and Comparative Toner (2) were mixed with hydrophobic silica fine powder, and then an image evaluation test was conducted on 1000 consecutive sheets using an FC-5 (manufactured by Canon) copying machine.

Observation of the obtained images revealed that the microcapsule toner (2) of the present invention had a high image density and was clear with little fog, but compared to that, the images of the comparative toner (2) deteriorated as the durability test progressed. The image density was significantly reduced and clearly inferior.

Further, when the photoreceptor drum and sleeve were observed, fused substances were observed only in the case of comparative toner (2).

[Effects of the Invention] As described above, the microcapsule toner produced by the production method of the present invention has good fixing properties even on plain paper, and has good fixing properties, durability against repeated copying, and good long-term storage stability. It is possible to obtain a microcapsule toner that is compatible with both of the following, and furthermore, an incomplete film does not occur, the shell material is not destroyed by external physical or mechanical force, and coalesced particles are generated. It is possible to provide a method for producing a microcapsule toner that does not require the use of microcapsules.

Claims (1)

[Claims] A positively charged resin composition is suspended and granulated in an aqueous medium in the presence of a negatively polarized dispersant to form suspended granulated particles coated with the negatively polarized dispersant. A method for producing a capsule toner, which comprises adding positively charged resin particles to an aqueous dispersion of suspended granulated particles to coat the suspended granulated particles.