JPH11167222A - Production of capsule toner for thermal pressure fixing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process capable of efficiently producing capsule toners for thermal pressure fixing of a narrow grain size distribution. SOLUTION: The production of the capsule toners for thermal pressure fixing having an atomization stage of agitating and dispersing a polymerizable compsn. contg. at least an ethylenic polymerizable monomer, hydrophilic resin and coloring agents into an aq. dispersion medium and atomizing this polymerizable compsn. in the aq. dispersion medium is executed in this process. In such a case, a high-speed agitating device which is an agitating device having a vessel having a circular section capable of housing the processing liquid to be subjected to agitating, a revolving shaft disposed at the center of this vessel and an agitating means mounted at this revolving shaft and has a driving source for driving this agitating means having a radius arriving near the inner peripheral surface of the vessel at a high speed above a peripheral speed of 20 m/second is used as the agitating device. The processing liquid to be subjected to the agitation is preferably so formulated as to contain 0.5 to 50 wt.% polymerizable compsn.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a capsule toner for heat and pressure fixing, which is used for developing an electrostatic latent image formed in electrophotography, electrostatic printing, electrostatic recording, and the like.

[0002]

2. Description of the Related Art Conventionally, various toners have been developed with the development of electrophotography, and not only conventional pulverized toners and the like but also, for example, JP-A-6-317925 and JP-A-7-175260. Development of a capsule toner for heat and pressure fixing comprising a core material and an outer shell provided so as to cover the surface of the core material as described in JP-A-9-15900 is also in progress.

However, after atomizing the polymerizable composition,
It is difficult to adjust a desired particle size of a capsule toner produced by polymerization. Therefore, in the capsule toner obtained by the conventional manufacturing method, there are some fine particles and coarse particles, and when printing by a copying machine or the like,
There are drawbacks such as the occurrence of disturbance in the image, and a classification step for adjusting the particle size distribution to an appropriate one is required. Also, unlike the pulverized toner, the capsule toner cannot reuse the fine particles and coarse particles removed in the classification step, and thus lacks productivity when the classification step is performed.

Therefore, there is a demand for a method for efficiently producing a capsule toner having a narrow particle size distribution without going through a classification step.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above prior art, and has as its object to provide a method capable of efficiently producing a capsule toner for heat and pressure fixing having a narrow particle size distribution. And

[0006]

The gist of the present invention is to provide (1)
A polymerizable composition containing at least an ethylenic polymerizable monomer, a hydrophilic resin and a colorant is stirred and dispersed in an aqueous dispersion medium, and the polymerizable composition is atomized in the aqueous dispersion medium. In the method for producing a capsule toner for heat and pressure fixing having a step of forming, a container having a circular cross section capable of containing a processing liquid to be stirred and a rotating shaft provided at the center of the container as a stirring device used for the stirring and dispersion. And a stirrer attached to the rotating shaft, wherein the stirrer has a radius reaching near the inner peripheral surface of the container, and the stirrer is moved at a peripheral speed of 20 m / sec or more at a high speed. (2) A method for producing a capsule toner for heat and pressure fixing, comprising using a high-speed stirring device provided with a driving source for driving, (2) the method according to (1), wherein the hydrophilic resin is an amorphous polyester or a hybrid resin. pressure Method for producing capsule toner for fixing, (3) Acid value of hydrophilic resin is 1 to 30 (KOHmg
(1) or (2), wherein the polymerizable composition is 0.5 to 50% by weight in the treatment liquid subjected to stirring. (1) The method for producing a capsule toner for heat and pressure fixing according to any one of (1) to (3), and (5) a hydrophilic resin in an amount of 2 to 5 based on 100 parts by weight of the ethylenic polymerizable monomer.
The present invention relates to the method for producing a capsule toner for thermal pressure fixing according to any one of the above (1) to (4), wherein 0 parts by weight are used.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The process for producing a capsule toner for heat and pressure fixing according to the present invention comprises the steps of: preparing a polymerizable composition containing at least an ethylenically polymerizable monomer, a hydrophilic resin and a colorant in an aqueous dispersion medium. In a method for producing a capsule toner for heat and pressure fixing, which has an atomization step of atomizing and dispersing the polymerizable composition in the aqueous dispersion medium by stirring and dispersing, the stirring is performed as a stirring device used for the stirring and dispersion. What is claimed is: 1. A stirring device comprising: a container having a circular cross section capable of storing a processing liquid; a rotating shaft provided at the center of the container; and a stirring device attached to the rotating shaft, wherein the stirring device has an inner peripheral surface A high-speed stirrer having a radius reaching the vicinity and having a driving source for driving the stirrer at a peripheral speed of 20 m / sec or more at a high speed is used.

The method for producing a capsule toner for heat and pressure fixing according to the present invention having an atomizing step is generally carried out in situ.
It belongs to a production method called a polymerization method. Incidentally, the in situ polymerization method of the present invention is described in JP-A-6-31792.
No. 5, JP-A-7-175260, JP-A-9-175
This is the same as the polymerization method disclosed in detail in, for example, JP-A-15900.

That is, in the in-situ polymerization method, the outer shell of the capsule toner is formed when the polymerizable composition is atomized in an aqueous dispersion medium and the hydrophilic resin is a liquid of an ethylenic polymerizable monomer. It can be carried out by utilizing the property of being unevenly distributed on the surface of the droplet (that is, unevenly distributed on the outermost layer of the particle). That is, in the in situ polymerization method, the difference between the solubility index of the hydrophilic resin and the ethylenic polymerizable monomer causes the ethylenic polymerizable monomer serving as the core material in the liquid droplets of the mixed solution to be exposed to the outside. Separation of the hydrophilic resin serving as a shell occurs, and in this state, polymerization of the ethylenically polymerizable monomer proceeds to form a capsule structure.

The polymerizable composition contains at least an ethylenically polymerizable monomer, a hydrophilic resin and a coloring agent. For example, a hydrophilic resin is dissolved in an ethylenically polymerizable monomer. Thereafter, it can be prepared by further adding a colorant and stirring.

Examples of the ethylenic polymerizable monomer include styrene and styrene derivatives such as styrene and α-methylstyrene; ethylenically unsaturated monoolefins such as ethylene and propylene; diolefins such as butadiene; Halovinyls such as vinyl chloride;
Vinyl esters such as vinyl acetate and vinyl propionate; ethylenic monocarboxylic acids such as (meth) acrylic acid; alkyl (C1-18) esters of (meth) acrylic acid; (meth) acrylic acid 2 Esters of ethylenic monocarboxylic acids such as hydroxyethyl, glycidyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate; vinyl ethers such as vinyl methyl ether; vinylidene chloride and the like And N-vinyl compounds such as N-vinylpyrrole and N-vinylpyrrolidone. Of these, styrene, α-methylstyrene, propylene, methyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, methyl methacrylate, butyl methacrylate, and 2-hydroxyethyl methacrylate are preferred.

In the present invention, the ethylenic polymerizable monomer contains 50 to 90% by weight of styrene or a styrene derivative which forms the main skeleton of the resin, and has a heat resistance such as a softening point and a glass transition point of the resin. It is preferable to contain 10 to 50% by weight of an ethylenic monocarboxylic acid or an ester thereof for controlling the properties.

The polymerizable composition may contain a polymerization initiator used for polymerizing the ethylenically polymerizable monomer and, if necessary, a crosslinking agent.

The hydrophilic resin used in the present invention includes:
For example, amorphous polyesters, hybrid resins, polyamides, polyester polyamides, polyureas and the like can be mentioned. Among these, amorphous polyesters and hybrid resins are preferable from the viewpoint of fixability and storage stability.

The amorphous polyester used in the present invention includes, for example, those obtained by a production method described in JP-A-7-175260.

As described in JP-A-8-171231, the above-mentioned hybrid resin used in the present invention is obtained by mixing two polymerizable raw material monomer mixtures each having an independent reaction path, It is obtained by performing two polymerization reactions in the same reaction vessel.

In the present invention, the two polymerization reactions are:
The polymerization reaction is carried out mainly by independent reaction paths, and is preferably a reaction that produces a condensation polymerization resin and an addition polymerization resin. Typical examples of the polycondensation resin include polyester, polyester polyamide, and polyamide, and typical examples of the addition polymerization resin include a vinyl resin obtained by a radical polymerization reaction.

Specific examples of the hybrid resin used in the present invention include those described in JP-A-8-171231.

In the present invention, the acid value of the hydrophilic resin is set so that the hydrophilic resin serving as the outer shell can easily come out of the interface during in situ polymerization and improve the storage stability of the toner. It is preferably 1 (KOHmg / g) or more, preferably 5 (KOHmg / g) or more, and from the viewpoint of production stability, it is 30 (KOHmg / g) or less, preferably 15 (KOHmg / g) or less. desirable. The acid value of the hydrophilic resin is determined according to JIS K007.
It can be measured according to a method based on 0.

The softening point of the hydrophilic resin is 90 ° C. from the viewpoint of high-temperature offset property, storage stability and stress resistance.
The temperature is preferably 95 ° C. or higher, and is 140 ° C. or lower, preferably 130 ° C. or lower, in order to facilitate the melting and softening of the outer shell of the toner and to improve the low-temperature fixability. The softening point of the hydrophilic resin can be measured using a Koka type flow tester.

The glass transition point of the hydrophilic resin is 50 ° C. or higher, preferably 55 ° C., from the viewpoint of storage stability of the toner.
The temperature is desirably at least 80 ° C., preferably at most 75 ° C., from the viewpoint of toner fixability. The glass transition point of the hydrophilic resin can be measured using a differential scanning calorimeter.

From the viewpoint of storage stability, the amount of the hydrophilic resin used is preferably at least 0.5 part by weight, more preferably at least 5 parts by weight, based on 100 parts by weight of the ethylenically polymerizable monomer. Desirably, from the viewpoint of fixability, 50 parts by weight or less,
Preferably, it is not more than 20 parts by weight.

As the colorant used in the present invention, all of the dyes and pigments used as conventional colorants for toner can be used. For example, carbon black, phthalocyanine blue, permanent brown FG,
Brilliant First Scarlet, Pigment Green B, Rhodamine-B Base, Solvent Red 49,
Solvent Red 146, Solvent Blue 35, Quinacridone, Carmine 6B, Disazo Yellow, and the like. These can be used alone or in combination of two or more. The amount of the colorant used is preferably about 2 to 25 parts by weight based on 100 parts by weight of the ethylenically polymerizable monomer.

In the present invention, the polymerizable composition includes:
If necessary, an additive may be appropriately contained. Here, as additives, charge control agents, fluidity improvers, cleaning improvers, conductive fillers, extenders, reinforcing fillers such as fibrous substances, antioxidants, antioxidants, anti-offset agents, and the like. These may be used alone or in combination of two or more. In the present invention, the additive may be added together with the raw material monomer when the hydrophilic resin is produced, and may be contained in the hydrophilic resin.

Next, the polymerizable composition is stirred and dispersed in an aqueous dispersion medium, and the polymerizable composition is atomized in the aqueous dispersion medium. It is necessary to stabilize the volatile composition in an oil droplet state.

In the present invention, as the stirring device used for the stirring and dispersion, a container having a circular cross section capable of storing the processing liquid to be stirred as described above, a rotating shaft provided at the center of the container, A stirrer having a stirrer attached to the rotating shaft, wherein the stirrer has a radius reaching near an inner peripheral surface of the container, and drives the stirrer at a peripheral speed of 20 m / sec or more at a high speed. There is one major feature in using a high-speed stirring device having a driving source.

When the above-mentioned stirring device is used, the processing solution is pressed against the inner surface of the container by centrifugal force by the rotation of the processing solution accompanying the rotation of the stirrer of the high-speed stirring device, and the processing solution is formed into a hollow thin film. Since the dispersion is stirred and dispersed, the treatment liquid can be atomized. Here, the gap between the end of the stirrer and the inner peripheral surface of the container is not particularly limited as long as the processing liquid is formed in a hollow thin film shape as described above.
For example, it is about 2 to 20 mm, and the peripheral speed is 20 m /
Seconds or more, preferably 25 m / s or more.

Specific examples of the stirring device include those described in JP-A-9-75698, for example, "TK Filmix" (trade name, manufactured by Tokushu Kika Kogyo Co., Ltd.) Commercially available products such as

In the present invention, a mixed liquid comprising the polymerizable composition and the aqueous dispersion medium is supplied to the stirring device as a treatment liquid to be subjected to the stirring. In the present invention, since the polymerizable composition in the treatment liquid subjected to the stirring contains the hydrophilic resin, the affinity for the aqueous dispersion medium is high, and thus the stirring used in the present invention is performed. It is presumed that the stirring effect of the device can be effectively exerted, whereby a capsule toner having a very narrow particle size distribution can be obtained.

The aqueous dispersion medium used in the present invention includes:
For example, water and a mixed dispersion medium of water and an organic solvent such as methanol, ethanol, propanol, acetone, tetrahydrofuran, dioxane and the like can be mentioned, and it is particularly preferable to use water alone.

In the production method of the present invention, in order to prevent aggregation and coalescence of the polymerizable composition, it is preferable that a dispersion stabilizer is contained in the dispersion medium. Such dispersion stabilizers include, for example, gelatin, polyvinyl alcohol, polystyrene sulfonic acid, hydroxymethyl cellulose,
Hydroxyethyl cellulose, sodium carboxymethyl cellulose, sodium polyacrylate, sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, sodium oleate, sodium laurate, potassium stearate, colloidal silica, alumina, tricalcium phosphate, and the like. , Or a mixture of two or more.

The polymerizable composition contained in the treatment liquid subjected to stirring is desirably 0.5% by weight or more, preferably 20% by weight or more, from the viewpoint of the stability of the state of oil droplets. From the viewpoint of an appropriate particle size distribution, the content is desirably 50% by weight or less, preferably 40% by weight or less.

On the other hand, the amount of the aqueous dispersion medium contained in the treatment liquid subjected to stirring is desirably 50% by weight or more, preferably 60% by weight or more, from the viewpoint of the stability of the oil droplet state. From the viewpoint of a proper particle size distribution, the content is desirably 99.5% by weight or less, preferably 80% by weight or less.

In the atomization step using the stirring device, in addition to the batch method, the polymerizable composition and the aqueous dispersion medium are supplied from the bottom of the container at a constant ratio and the residence time in the container is constant. It is also possible to perform continuous processing by continuously discharging the water from the upper part of the container by supplying the water continuously using a pump or the like.

Next, the processing liquid stirred and dispersed by using the above-mentioned stirring device is disclosed in JP-A-6-317925 and JP-A-7-317925.
It is subjected to in-situ polymerization by the methods described in JP-A-175260, JP-A-9-15900 and the like.

After polymerizing the polymerizable composition, the dispersion stabilizer is destabilized using hydrochloric acid or the like, and the above-mentioned ethylenic polymerizable monomer is obtained by performing operations such as filtration, washing and drying. A hot-press fixing comprising a heat-fusible core material containing a thermoplastic resin obtained by polymerization and the coloring agent, and an outer shell made of a hydrophilic resin provided so as to cover the surface of the heat-fusible core material. Capsule toner can be obtained.

In the present invention, the capsule toner for heat and pressure fixing obtained as described above is used as a precursor particle, and further described in JP-A-6-317925, JP-A-7-175260 and JP-A-9-175. Seed polymerization described in JP-A-15900 may be performed.

The capsule toner for heat and pressure fixing obtained by the production method of the present invention has a very narrow particle size distribution and its average particle size is not particularly limited, but it is usually 3 to 30 μm. preferable. The average particle size of the toner can be adjusted by the concentration of the dispersant, stirring conditions (stirring speed, time), and the like.

Further, the thickness of the outer shell of the capsule toner for heat and pressure fixation is to improve blocking resistance.
It is preferably 0.01 μm or more, and more preferably 1 μm or less in order to improve the thermal fusibility. The outer shell of the toner can be adjusted by the amount of the hydrophilic resin added and the average particle size of the toner.

The softening point of the capsule toner for heat and pressure fixing is 70 ° C. or higher, preferably 8 from the viewpoint of storage stability.
0 ° C. or higher is desirable.
The temperature is desirably 60 ° C or lower, preferably 150 ° C or lower. The softening point of the heat and pressure fixing capsule toner is as follows:
It can be measured using a Koka flow tester.

The heat and pressure fixing capsule toner is used alone as a developer when it contains a magnetic fine powder, and is used as a non-magnetic monocomponent when it does not contain a magnetic fine powder. It can be used as a two-component developer as a system developer or as a mixture with a carrier. The carrier is not particularly limited, but includes iron powder,
Ferrite, glass beads or the like, or those obtained by coating them with a resin, or a resin carrier obtained by kneading magnetite fine powder or ferrite fine powder into a resin is used. The amount of the capsule toner used when mixing the capsule toner and the carrier is 0.5 to 2 parts by weight per 100 parts by weight of the carrier.
It is desirably about 0 parts by weight. Further, the average particle diameter of the carrier is preferably about 15 to 500 μm.

The capsule toner for heat and pressure fixing gives a good fixing strength to an image formed by fixing to a recording material such as paper by using both heat and pressure. As the heat and pressure fixing method, if both heat and pressure are used, a known heat roller fixing method, for example, as described in JP-A-2-190870, an unfixed toner image on a recording material is heated. By a heating means composed of a heat-resistant sheet and heat-fused through the heat-resistant sheet, a fixing method for fixing, for example, as described in JP-A-2-162356, a fixed and supported heating element, By a pressure member that is in opposing pressure contact with the heating body, and that makes the recording material adhere to the heating body via the film,
A method such as a method in which a visible image of the toner is heated and pressed and fixed on a recording material may be used. All of these methods are suitable for fixing the capsule toner obtained by the production method of the present invention to a recording material.

[0043]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the present invention.

The softening point, glass transition point and acid value of the resins described in the examples were measured by the following methods.

[Softening point of resin] Using a Koka type flow tester (manufactured by Shimadzu Corporation, trade name: CFT-500), while heating 1 g of the sample at a heating rate of 6 ° C / min, the plunger was used. To give a load of 1.9 MPa and a diameter of 1 m
m, a nozzle having a length of 1 mm is extruded, whereby a plunger descent amount (flow value) -temperature curve of the flow tester is drawn. When the height of the S-shaped curve is h, h /
The temperature corresponding to 2 (the temperature at which half of the resin flows out) is defined as the softening point.

[Glass transition point of resin] Differential scanning calorimeter (trade name: DSC210, manufactured by Seiko Instruments Inc.)
The temperature was raised to 200 ° C. using the
The sample cooled to 0 ° C at 0 ° C / min is heated at a rate of 10 ° C.
The temperature at the intersection of the extension of the base line below the glass transition point and the tangent line indicating the maximum slope from the rising portion of the peak to the peak of the peak when measured at / min is defined as the glass transition point.

[Acid value of resin] It is measured by a method according to JIS K0070.

Resin Production Example 1 Polyoxypropylene (2.2) -2,2-bis (4-
(Hydroxyphenyl) propane 311.6 g, polyoxyethylene (2.2) -2,2-bis (4-hydroxyphenyl) propane 78.3 g, terephthalic acid 366.
3 g and 3.8 g of trimellitic anhydride were placed in a glass two-liter four-necked flask, fitted with a thermometer, a stainless steel stir bar, a falling condenser, and a nitrogen inlet tube. Under the airflow 2
The reaction was performed at 20 ° C.

The degree of polymerization is tracked by the softening point measured according to the method according to ASTM E28-67,
The reaction was terminated when the softening point reached 115 ° C. The obtained resin is referred to as resin A. Resin A has a softening point of 113.
1 ° C., glass transition point 68.8 ° C., acid value 10.2 (K
OH mg / g).

Resin Production Example 2 Styrene 490 was used as a raw material monomer of the vinyl resin.
g, 2-ethylhexyl acrylate 73 g, acrylic acid 25 g as a bi-reactive compound, and ditertiary butyl peroxide 22 g as a polymerization initiator were placed in a dropping funnel. As raw material monomers for polyester, 1425 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane and polyoxyethylene (2.2) -2,2-bis (4-hydroxyphenyl) propane 273 g, 790 g of terephthalic acid and 5 g of dibutyltin oxide as an esterification catalyst were placed in a glass 5-liter four-necked flask equipped with a thermometer, a stainless steel stirrer, a falling condenser, and a nitrogen inlet tube. In a nitrogen atmosphere, while stirring at a temperature of 160 ° C., the raw material monomer of the vinyl resin, the amphoteric compound and the polymerization initiator were dropped from the dropping funnel over 1 hour. After aging the addition polymerization reaction for 2 hours while maintaining the temperature at 160 ° C., the temperature was raised to 230 ° C. to cause the polycondensation reaction.

The degree of polymerization was monitored by a softening point measured according to a method according to ASTM E28-67, and the reaction was terminated when the softening point reached 110 ° C. The obtained resin is referred to as resin B. Resin B has a softening point of 110.0
° C, the glass transition point is 65.2 ° C, and the acid value is 11.0 (KO
Hmg / g).

Example 1 74 parts by weight of styrene, 2-ethylhexyl acrylate 2
To 6 parts by weight and 0.2 parts by weight of divinylbenzene, 10 parts by weight of resin A was added and dissolved. After dissolving the resin A, 20 parts by weight of the grafted carbon black “504P” (trade name, manufactured by Ryoyu Kogyo Co., Ltd.) is added, and the mixture is stirred for 1 hour using a magnetic stirrer. By adding 2 parts by weight of azobisisobutyronitrile, 240 g of a polymerizable composition was obtained. Then, 240 g of the polymerizable composition was added to 560 g of an aqueous colloid solution of 5% by weight of tricalcium phosphate prepared in advance, and T.P. K. Using Fillmix (trade name, manufactured by Tokushu Kika Kogyo Co., Ltd.), a brush-shaped stirrer with a gap of 3 mm from the inner surface of the container was used at 15 ° C.
Was stirred at a peripheral speed of 25 m / sec for 30 seconds to obtain 800 g of finely divided material. Next, tricalcium phosphate 5 previously prepared in a 2 liter glass separable flask was used.
80 g of an aqueous colloidal solution of 80% by weight
0 g was added, and the flask was covered with a four-neck glass lid, fitted with a reflux condenser, a thermometer, a nitrogen introducing pipe, and a stainless steel stirrer, and was set on an electric heating mantle heater. While stirring the mixture under a nitrogen atmosphere, the temperature was raised to 70 ° C. and the polymerization reaction was performed for 10 hours. After cooling, a 10% by weight aqueous hydrochloric acid solution was added, filtered, washed with water, and air-dried at 45 ° C.
By drying under reduced pressure at 2.6 kPa for 12 hours,
A capsule toner having an outer shell made of amorphous polyester was obtained. The particle size distribution of the capsule toner was measured using a Coulter counter (trade name, manufactured by Coulter Co., Ltd.) using an aperture having a diameter of 100 μm. The weight-median particle size (D) was 5.5 μm, and the variation in the particle size distribution was measured. Coefficient is 26
%, The content of fine particles having a particle size of D / 2 or less is 1
% By weight, the content of coarse particles having a particle diameter of 2D or more was 0.5% by weight.

Next, the unclassified capsule toner 10
0 parts by weight of hydrophobic silica "Aerosil silica R-97"
2 "(manufactured by Nippon Aerosil Co., Ltd., trade name) was subjected to a printing test using a commercially available copying machine, and the obtained image was free from fog and scattering, and had gradation characteristics. And a very sharp image was obtained.

Example 2 In Example 1, the T.V. K. A capsule toner having an outer shell made of an amorphous polyester was prepared in the same manner as in Example 1 except that the peripheral speed of Fillmix (trade name, manufactured by Tokushu Kika Kogyo Co., Ltd.) was changed to 20 m / sec. Obtained. When the particle size distribution of the capsule toner was measured using a Coulter counter (trade name, manufactured by Coulter Co., Ltd.), the weight median particle size (D) was 8.7 μm, and the variation coefficient of the particle size distribution was 24.
%, The content of fine particles having a particle size of D / 2 or less was 1.5% by weight, and the content of coarse particles having a particle size of 2D or more was 0.1% by weight.

Example 3 An encapsulated toner having an outer shell of a hybrid resin was obtained in the same manner as in Example 1 except that resin B was used instead of resin A. The particle size distribution of the capsule toner was measured using a Coulter Counter (Coulter Co., Ltd.,
As a result, the median particle diameter (D) was 5.8 μm, the coefficient of variation of the particle size distribution was 24%, and the
The content of fine particles having a particle size of not more than / 2 was 1.2% by weight, and the content of coarse particles having a particle size of 2D or more was 0.3% by weight.

Comparative Example 1 K. Instead of Fillmix (trade name, manufactured by Tokushu Kika Kogyo Co., Ltd.), T.I. K. Using a homomixer (trade name, manufactured by Tokushu Kika Kogyo Co., Ltd.), 120
A capsule toner having an outer shell of amorphous polyester was obtained in the same manner as in Example 1, except that stirring was performed at 00 rpm for 4 minutes. When the particle size distribution of the capsule toner was measured using a Coulter counter (trade name, manufactured by Coulter Co., Ltd.), the weight median particle size (D) was 5.4 μm.
m, the coefficient of variation of the particle size distribution is 47%, the content of fine particles having a particle size of D / 2 or less is 4.6% by weight, and the content of coarse particles having a particle size of 2D or more is 3.3% by weight. Met.

Next, the unclassified capsule toner 10
0 parts by weight of hydrophobic silica "Aerosil silica R-97"
2 "(manufactured by Nippon Aerosil Co., Ltd., trade name), 0.4 parts by weight were externally added, and a printing test was performed using a commercially available copying machine. As a result, the obtained image had a large content of fine particles in the toner. As a result, the image lacked gradation because of a large amount of fog and a large content of coarse particles.

Comparative Example 2 A toner was obtained in the same manner as in Example 1 except that the resin A was not used. The particle size distribution of this toner was measured using a Coulter counter (trade name, manufactured by Coulter Co., Ltd.). The weight median particle size (D) was 5.7 μm, the variation coefficient of the particle size distribution was 36%, and D / 2. The content of the fine particles having the following particle diameters is 2.6% by weight,
The content of coarse particles having a particle diameter of D or more was 2.1% by weight.

As can be seen from the above results, Examples 1 to
In the case of No. 3, a capsule toner having a very narrow particle size distribution is obtained, whereas the capsule toner obtained in Comparative Example 1 in which the stirring and dispersion in the atomization step is performed using a conventional stirring device is a capsule toner having a very wide particle size distribution. It can be seen that the toner is a toner. Furthermore, from the printing tests in Example 1 and Comparative Example 1, when the capsule toner obtained in Comparative Example 1 was used, fog caused by fine particles and scattering caused by coarse particles were large, and gradation was poor. In contrast to the case where a chipped image is obtained, when the capsule toner obtained in Example 1 is used, it is found that a very sharp image is obtained without fogging or scattering. Further, the toner obtained in Comparative Example 2 did not use a hydrophilic resin.
Even if a stirring device similar to that described above is used, a toner having a narrow particle size distribution cannot be obtained, indicating that a hydrophilic resin is required to obtain a capsule toner having a narrow particle size distribution.

[0060]

According to the present invention, a capsule toner for heat and pressure fixing having a narrow particle size distribution can be efficiently produced.

Claims (5)

[Claims] 1. A polymerizable composition containing at least an ethylenic polymerizable monomer, a hydrophilic resin and a colorant is stirred and dispersed in an aqueous dispersion medium, and the polymerizable composition is dispersed in the aqueous dispersion medium. In the method for producing a capsule toner for heat and pressure fixing having an atomization step of atomizing with a container, as a stirring device used for the stirring and dispersion, a container having a circular cross section capable of holding a processing liquid to be stirred, and a center of the container A stirrer having a rotating shaft provided on the rotating shaft and a stirrer attached to the rotating shaft, wherein the stirrer has a radius reaching near the inner peripheral surface of the container, and the stirrer has a peripheral speed of 20 m. A method for producing a capsule toner for heat and pressure fixing, comprising using a high-speed stirring device provided with a driving source that drives at a high speed at a speed of not less than / sec. 2. The method according to claim 1, wherein the hydrophilic resin is an amorphous polyester or a hybrid resin. 3. An acid value of the hydrophilic resin is 1 to 30 (KOHm
g / g). 4. The method for producing a capsule toner for heat and pressure fixing according to claim 1, wherein the polymerizable composition is contained in the treatment liquid subjected to stirring in an amount of 0.5 to 50% by weight. 5. The method according to claim 1, wherein the hydrophilic resin is used in an amount of 2 to 50 parts by weight based on 100 parts by weight of the ethylenic polymerizable monomer.
5. The method for producing a capsule toner for heat and pressure fixing according to any one of claims 4 to 4.