JP3437433B2 - Method for producing toner for developing electrostatic images - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a toner for developing an electrostatic image.

[0002]

BACKGROUND OF THE INVENTION Electrophotography is described in US Pat. No. 2,297,
Numerous methods are known, as described in US Pat. Generally, a photoconductor made of a photoconductive substance is used, an electrostatic charge image is formed on the photoconductor by various means, and then the electrostatic charge image is developed with a toner to form a toner image, After the toner image is transferred to a transfer material such as paper, if necessary, the toner image is fixed on the transfer material by heating, pressing, heating and pressing to obtain a copy or a printed matter. Further, various methods have been conventionally proposed as a method of developing with toner or a method of fixing a toner image.

Conventionally, toners used for these purposes are
Generally, a colorant comprising a dye or a pigment is melt-kneaded in a thermoplastic resin, and after being uniformly dispersed, finely pulverized by a fine pulverizer, and the finely pulverized product is classified by a classifier to obtain a desired particle size. Have been manufactured.

Although a very good toner can be produced by this production method, there is a limitation in the selection range of the toner material. For example, a resin composition in which a colorant is dispersed is sufficiently brittle,
It must be easily milled with a milling device. However, when the resin composition is fragile in order to satisfy these requirements, when the resin composition is actually finely pulverized at a high speed, the particle size range of the formed particles tends to be wide,
In particular, there is a problem that a large amount of fine particles are likely to be generated in a relatively large proportion. In addition, toners obtained from such brittle materials are susceptible to further milling in the copier or printer developer. Further, in the melt-kneading method, it is difficult to uniformly disperse solid fine particles such as a colorant in the resin, and depending on the degree of the dispersion, an increase in fog during image formation, a decrease in image density, color mixing or transparency. Will cause a defect. Therefore, great care must be taken in dispersing the colorant. In addition, the exposure of the colorant on the fracture surface of the crushed particles may cause fluctuations in the developing characteristics.

In order to overcome the problems of the toner by the melt-kneading-pulverizing method, Japanese Patent Publication No. 36-10231,
Suspension polymerization toners are proposed by JP-A-43-10799 and JP-A-51-14895, and various polymerization toners and manufacturing methods thereof are also proposed. For example, in a method for producing a toner by a suspension polymerization method, a polymerizable monomer, a colorant and a polymerization initiator, and if necessary, a crosslinking agent, a charge control agent, and other additives are uniformly dissolved or dispersed to perform polymerization. Of the polymerizable monomer composition, the polymerizable monomer composition is dispersed in an aqueous medium containing a dispersion stabilizer by using a suitable stirrer, and at the same time, a polymerization reaction is performed to obtain a desired particle size. To obtain toner particles having.

In this method, since the crushing step is not included, the toner particles do not need to be brittle, a soft material can be used as the resin, and the colorant is hardly exposed on the surface of the toner particles. However, there is an advantage that toner particles having uniform triboelectric charging properties can be obtained. Further, since the particle size distribution of the obtained toner is relatively sharp, the classification step can be omitted, or even if the classification is performed, the toner can be obtained in high yield. Further, since a large amount of the low softening point substance can be included in the toner particles, there is an advantage that the obtained toner has excellent offset resistance.

In the production of a toner by a polymerization method, a polymerization step for preparing a polymerizable monomer composition containing at least a polymerizable monomer and a colorant, and the polymerizable monomer composition is subjected to a high shear force by an aqueous medium. It is essential to control the temperature of the reaction system in the granulation step of producing the particles of the polymerizable monomer composition and the polymerization step of polymerizing the particles of the polymerizable monomer composition. is there. Conventionally, a method of using hot water as a heat source is generally used as a method of heating and maintaining a constant temperature. However, hot water heating has problems such as poor productivity, high cost for heating water, and large maintenance due to corrosion and scale accumulation in the jacket. The method of filling the jacket with steam at atmospheric pressure or higher, that is, saturated steam at 100 ° C. or higher has good temperature responsiveness, but the temperature difference between the jacket temperature and the object to be processed is large, so Since the fluctuation range is large and it is difficult to maintain the temperature constant, it is likely to cause deterioration of quality.

Further, since a deposit is likely to adhere to the inner wall of the container used in the polymerization step, glass lining or fluororesin is preferably used as the material of the container. Since heat transfer is poor in such a material as compared with a general metal material, poor temperature responsiveness becomes a problem especially when a temperature control method using hot water as a heat source is used.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a toner for developing an electrostatic image by a polymerization method, which is excellent in temperature responsiveness and which can easily keep a reaction system at a constant temperature. To do.

An object of the present invention is to provide a manufacturing method capable of shortening the manufacturing time as compared with the conventional method.

An object of the present invention is to provide a method for producing a toner having excellent fixability.

[0012]

The present invention provides a mixing step for preparing a polymerizable monomer composition containing at least a polymerizable monomer and a colorant, wherein the polymerizable monomer composition is subjected to high shearing force. , A granulation step of dispersing in an aqueous medium to granulate particles of the polymerizable monomer composition, and polymerizing the polymerizable monomer in the particles of the polymerizable monomer composition to produce toner particles a method for producing a toner having a polymerization step of, the polymerization step have a jacket, the inner wall is made in the container that is glass lining, while adjusting the degree of vacuum in the jacket, pressure in the jacket A method for producing an electrostatic charge image developing toner, characterized in that the temperature of the liquid temperature in the container is controlled by supplying steam, and the degree of vacuum in the jacket is adjusted to 10 to 90 kPa. .

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The method for producing a toner of the present invention has at least a mixing step, a granulating step and a polymerization step. In the mixing step, a polymerizable monomer, a colorant, a release agent and a polymerization initiator, and further a crosslinking agent, a charge control agent, if necessary,
Other additives are uniformly mixed or dispersed to prepare a polymerizable monomer composition. In the granulation step, the polymerizable monomer composition is dispersed in an aqueous medium phase containing a dispersion stabilizer by a stirring means having a high shearing force to obtain a polymerizable monomer composition having a desired particle size. To produce particles. Further, in the polymerization step, the polymerizable monomer in the particles of the polymerizable monomer composition is polymerized to produce toner particles. After the reaction is completed, the produced toner particles are collected by washing and filtration, and then dried.

In the polymerization step, the polymerization temperature of the reaction system is 40 ° C.
As described above, the polymerization is generally performed at a temperature of 50 to 90 ° C. Further, it is very important to control the temperature of the contents in the mixing process and the granulating process.

As a result of earnest studies, the present inventors have found that it is very preferable to use water vapor having an absolute pressure lower than atmospheric pressure as a heat source as a method for controlling the temperature of the reaction system.

Further, the container used in the manufacturing process of the polymerized toner is required to have an excellent temperature responsiveness and an inner wall member quality to which contents are unlikely to adhere.

As a heat source excellent in temperature responsiveness, high-pressure steam at atmospheric pressure or higher is generally used.
Saturated steam of 00 ° C. or higher is preferable, and when the temperature of the solution in the container is raised, it can be efficiently performed in a very short time. However, in the production process of suspension polymerization toner,
As described above, since the polymerization is usually carried out at a temperature of 50 to 90 ° C., the temperature difference between the temperature of the contents and the jacket becomes large, and when controlling the reaction system at a constant temperature, the fluctuation range becomes large. Prone and difficult to control. Although a heat source is supplied into the jacket, when the jacket is filled with high-pressure steam, the temperature in the jacket exceeds 100 ° C., so that there is a problem that the reactant adheres strongly to the inner wall surface of the container. Hot water heating is often used as a method of low temperature heating. In the case of heating with warm water, the problems of control accuracy of maintaining a constant temperature and adhesion in the container are solved to some extent. However, since the hot water heating uses sensible heat, the hot water temperature is likely to drop, and the heating amount is reduced, so that the rate of temperature rise is slowed and the productivity is reduced. In addition, since hot water requires a large amount of energy to control the temperature, the cost required for manufacturing the toner increases.

On the other hand, the toner manufacturing method of the present invention can solve such a problem.

The present invention is achieved by using steam having an absolute pressure lower than atmospheric pressure as a heat source. In the case of saturated steam, the lower the absolute pressure is, the larger the "latent heat amount" is. Therefore, filling the jacket with water vapor having a low absolute pressure is an efficient use of energy and is very efficient. . Further, as a heat source, in principle, only "latent heat" associated with a change in the state of water vapor is used, and there is almost no temperature drop, resulting in good thermal efficiency. Furthermore, by bringing the temperature of water vapor close to the control temperature of the contents,
The temperature of the contents can be kept more constant, and the quality stability is increased. The absolute pressure (that is, the degree of vacuum) of water vapor in the jacket used is preferably controlled to 10 to 90 kPa, more preferably 10 kPa to 80 kPa.

The high-pressure steam supplied into the jacket is preferably saturated steam, and the steam in the jacket is also preferably saturated steam. In the case of saturated steam, the temperature of the steam can be known if the vapor pressure is known. Therefore, it is preferable to use saturated steam when controlling the temperature.

The polymerization vessel used in the polymerization step is
It has a jacket structure. The inside of this jacket is decompressed, high-pressure steam is supplied to it, and steam having an absolute pressure lower than atmospheric pressure is produced. The steam is used as a heat source to indirectly heat the solution. When a heat source is directly supplied into the polymerization container, high-temperature heat is directly transferred to the contents, and the polymerization reaction tends to be nonuniform.

Further, it is preferable that the mixing vessel and the granulating vessel used in the mixing step and the granulating step also have a jacket structure, and the inside of the jacket is decompressed, and high-pressure steam is supplied thereto to obtain an absolute pressure. It is preferable to generate steam lower than atmospheric pressure and indirectly heat the solution by using the steam as a heat source.

Another problem in the production process of the suspension polymerization toner is the adhesion of the polymerizable monomer composition in the container. In particular, it becomes a big problem in the polymerization container. The scale of the polymer adheres strongly to the inner wall of the polymerization container, and if the adherence becomes violent, the temperature control is affected, and if the adhered material peels off, it becomes an impurity in the product, causing quality problems. In particular, in the case of temperature control using high-pressure steam, since the temperature of the jacket is high, deposits are likely to be generated on the inner wall of the container. Therefore, as a countermeasure against this adhesion, a glass lining, a coating with a fluororesin, or a lining is generally often used for the inner wall of the container. However, in this case, although the adhesion inside the container is eliminated, the heat transfer from the tank jacket is lower than that of the iron-based material, so that there is a problem that the temperature rising rate during temperature increase or the temperature decrease rate during temperature decrease becomes slow. It is easy to occur. In the case of heating with warm water, a particularly significant problem occurs.

However, when steam of which absolute pressure is lower than atmospheric pressure is used in the method of the present invention, thermal efficiency is better than that of hot water, and therefore such a problem is also solved. That is, it is possible to achieve a method for producing a suspension-polymerized toner that reduces adhesion in a polymerization container, has excellent temperature responsiveness, and easily keeps a reaction system at a constant temperature.

Normally, the temperature of each container is controlled by detecting the temperature of the contents in the container with a temperature sensor and controlling the degree of vacuum in the jacket based on the information.

The apparatus used in the mixing step of the method of the present invention is not particularly limited, but a vertical cylindrical (jacket specification) container equipped with a stirrer is usually used. It suffices that the inside of the tank can be uniformly stirred, and normally, paddle blades, anchor blades, screw blades and the like are preferably used, and they are appropriately selected and used depending on the physical properties of the contents. Further, as the container, an iron-based container, an inner wall portion coated with glass lining or a fluororesin, or the like can be used. In the mixing step, at least a releasing agent, a colorant and a polymerization initiator in the polymerizable monomer, further a crosslinking agent, a charge control agent, if necessary,
Other additives are mixed or dispersed uniformly.

An apparatus equipped with a stirrer having a high shearing force is preferably used in the granulating step of the method of the present invention.
As a stirrer having a high shearing force, T.I. K. Homo Mixer (Special Kika Kogyo Co., Ltd.), Clearmix (M
Technique Co., Ltd.) is preferably used. These devices are composed of a rotating blade (rotor) and a fixed blade (stator) that rotate at high speed, and atomize them by the action of a strong shearing force generated in a minute gap between them. The container used in the granulation step may be an iron-based container, or a container having an inner wall portion coated with glass lining or a fluororesin, or the like.

Usually, when granulating with such an apparatus,
The polymerizable monomer composition is placed in a granulation container in which a liquid dispersion medium that is incompatible with the monomer composition is charged and dispersed to perform granulation. The particle size of the obtained particles is usually controlled by the amount of the dispersion stabilizer used and the rotation speed of the stirring blade.

Further, in the polymerization step of the method of the present invention, the particles produced in the granulation step are polymerized to solidify.
By changing the stirring conditions of the apparatus used in the granulation step, it may also serve as the granulation apparatus and the polymerization apparatus, but generally, as a separate apparatus, the contents are transferred from the granulation apparatus to the polymerization apparatus, The polymerization reaction is completed in a polymerization container to obtain solid particles.
The apparatus used in this polymerization step is not particularly limited, but a vertical cylinder type (jacket specification) container equipped with a stirrer is usually used. The stirrer may be any type as long as it can uniformly stir the inside of the container, and normally, paddle blades, anchor blades, screw blades and the like are preferably used. In that case, an appropriate stirring state is required without applying an excessive shearing force that destroys the generated particles and preventing the particles from coalescing. This is controlled by the shape of the stirring blade, the rotation speed of the stirring blade, and the like. The container used in the polymerization step, those of iron, Although such materials as coated inner wall portion by glass lining or a fluorine resin is <br/>, in the present invention, in view of the container attachment, the inner wall portion A glass-lined container is used . After the completion of the reaction step, a vacuum distillation step for removing the residual monomer is carried out if necessary. It is preferable that this is also used as the reaction vessel for efficiency.

FIG. 2 is a schematic explanatory view showing a specific example of the apparatus used in the polymerization step.

In FIG. 2, 1 is a polymerization vessel, 2 is a vacuum generator, 3 is a stirrer, 4 is a tank jacket, 5, 6 and 8 are control valves, 7 is a temperature detection device, 9 is a high pressure steam supply device, Reference numeral 10 is a computer, and 11 is a cooling means.

In this apparatus, the inside of the tank jacket 4 is decompressed by the vacuum generator 2, and high-pressure steam is supplied thereto via the control valve 5. By controlling the absolute pressure of water vapor in the jacket, the liquid temperature in the container can be efficiently controlled to a predetermined temperature.

At the time of cooling, cooling water is introduced through the control valve 6 to perform vacuum evaporation cooling. Regarding cooling, evaporative cooling under vacuum is more efficient than using only cooling water, and the amount of cooling water used can be small.

After the completion of the polymerization step, toner particles are obtained through a dispersant removing step, a solid-liquid separation step, and a drying step.

In the method for producing a toner of the present invention, the toner has a so-called core / shell structure in which the core portion is coated with an outer shell resin, and the fixing property and blocking resistance are such that the shell portion is formed by polymerization. It is particularly preferably used when producing a toner excellent in both.

As the main component of the core part, a low softening point substance is preferable, and a compound having a DSC endothermic maximum peak measured in accordance with ASTM D3418-8 in the range of 40 to 90 ° C. is preferable. When the maximum peak is less than 40 ° C., the self-cohesive force of the low softening point substance is weakened, and as a result, the high temperature offset resistance is weakened, which is not preferable. On the other hand, when the maximum peak exceeds 90 ° C., the fixing temperature becomes high, which is not preferable. Furthermore, when the temperature of the maximum peak value is high, a low softening point substance is precipitated during granulation, which hinders the suspension system, which is not preferable.

For measuring the temperature of the maximum endothermic peak value of the DSC of the present invention, for example, DSC-7 manufactured by Perkin Elmer Co. is used. The melting point of indium and zinc is used to correct the temperature of the device detection unit, and the heat of fusion of indium is used to correct the amount of heat. An aluminum pan was used as a sample and an empty pan was set as a control, and the temperature rising rate was 10 ° C./min. Measure with.

Specifically, paraffin wax, polyolefin wax, Fischer-Tropsch wax,
Amide wax, higher fatty acid, ester wax and their derivatives or their graft / block compounds can be used.

Further, the low softening point substance is added to the toner particles in an amount of 5 to 5.
It is preferable to add 30% by weight. If the amount added is less than 5% by weight, sufficient fixability cannot be obtained. If the amount added exceeds 30% by weight, toner particles are likely to coalesce during granulation even in the production by a polymerization method. The particle size distribution tends to be broad.

As a specific method of encapsulating the low softening point substance, a low softening point substance having a polarity smaller than that of the main monomer in the aqueous medium is used. In addition, a toner having a core / shell structure can be obtained by adding a resin or a monomer having a large polarity in the mixing step. The toner particle size distribution and particle size can be determined by changing the type and amount of the sparingly water-soluble inorganic salt or dispersant that acts as a protective colloid, and mechanical device conditions such as rotor speed, number of passes, stirring blade shape, etc. It can be controlled by changing the stirring conditions, the container shape, or the solid content concentration in the aqueous solution.

As a specific method for measuring the tomographic plane of the toner in the present invention, after the toner is sufficiently dispersed in a room temperature curable epoxy resin, the toner is cured in an atmosphere at a temperature of 40 ° C. for 2 days to obtain a cured product. After ruthenium tetraoxide and, if necessary, osmium tetraoxide are used together for dyeing, a flaky sample is cut out using a microtome equipped with diamond teeth and the toner morphology is measured using a transmission electron microscope (TEM). did. In the present invention, it is preferable to use the ruthenium tetroxide dyeing method in order to make a contrast between materials by utilizing a slight difference in crystallinity between the low softening point substance used and the resin constituting the outer shell.

The polymerizable monomer used in the present invention includes styrene, o- (m-, p-) methylstyrene, m
Styrenic monomers such as (p-)-ethylstyrene;
Methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, octyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, ( (Meth) acrylate monomers such as behenyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate; butadiene, isoprene, cyclohexene, An ene-based monomer such as (meth) acrylonitrile or (meth) acrylic acid amide is preferably used. These may be used alone or generally in the Polymer Handbook, Second Edition, Second Edition, III-P139-1.
92 (manufactured by John Wiley & Sons) has a theoretical glass transition temperature (Tg) of 40 to 80 ° C. The monomers are appropriately mixed and used. When the theoretical glass transition temperature is lower than 40 ° C., problems occur in the storage stability of the toner and the durability stability of the developer. On the other hand, when it exceeds 80 ° C., the fixing point rises. In this case, the color mixing of the toners of the respective colors is insufficient, the color reproducibility is poor, and the transparency of the OHP image is significantly reduced, which is not preferable in terms of high image quality.

In the present invention, when toner particles having a core / shell structure are manufactured, a polar resin may be added in addition to the outer shell resin in order to encapsulate the low softening point substance in the outer shell resin. Particularly preferred. As the polar resin used in the present invention, a copolymer of styrene and (meth) acrylic acid, a maleic acid copolymer, a saturated polyester resin, and an epoxy resin are preferably used. It is particularly preferable that the polar resin does not contain an unsaturated group capable of reacting with the shell resin or the monomer in the molecule. If a polar resin having an unsaturated group is used, a cross-linking reaction occurs with the monomer forming the outer shell resin layer, and as a full-color toner, in particular, it becomes extremely high in molecular weight and multicolor toner mixing occurs. Is disadvantageous and not preferable.

The number average molecular weight (Mn) of the polar resin used in the present invention is preferably in the range of 1,000 to 500,000.

As the colorant used in the present invention, carbon black, a magnetic substance, or a yellow / magenta / cyan colorant shown below, which is toned black, is used.

As the yellow colorant, condensed azo compounds, isoindolinone compounds, anthraquinone compounds,
Compounds represented by azo metal complexes, methine compounds and allylamide compounds are used. Specifically, C.I. I. Pigment Yellow 12, 13, 14, 15, 17, 6
2, 74, 83, 93, 94, 95, 109, 110,
111, 128, 129, 147, 168 and the like are used.

As the magenta colorant, a condensed azo compound, a diketopyrrolopyrrole compound, an anthraquinone, a quinacridone compound, a basic dye lake compound, a naphthol compound, a benzimidazolone compound, a thioindigo compound and a perylene compound are used. Specifically, C.I.
I. Pigment Red 2, 3, 5, 6, 7, 23, 4
8: 2, 48: 3, 48: 4, 57: 1, 81: 1, 1
44, 146, 166, 169, 177, 184, 18
5,202,206,220,221,254 etc. are especially preferable.

As the cyan colorant, a copper phthalocyanine compound and its derivative, an anthraquinone compound, a basic dye lake compound and the like can be used. Specifically, C.I. I.
Pigment Blue 1, 7, 15, 15: 1, 15: 2,
15: 3, 15: 4, 60, 62, 66 and the like can be used particularly preferably.

These colorants can be used alone or in a mixture, and can be used in the form of a solid solution. In the case of a color toner, the colorant used in the present invention is selected from the viewpoints of hue angle, saturation, brightness, environmental stability, OHP transparency, and dispersibility in the toner. The colorant is added in an amount of 1 to 20 parts by weight based on 100 parts by weight of the resin. When a magnetic substance is used as the black colorant, unlike other colorants, it is used by adding 40 to 150 parts by weight to 100 parts by weight of the resin.

The charge control agent used in the present invention includes
Although known compounds can be used, in the case of color toner, a charge control agent which is colorless and has a high charging speed of the toner and which can stably maintain a constant charge amount is particularly preferable. Furthermore,
A charge control agent having no polymerization inhibitory property and insoluble in an aqueous system is particularly preferable. Specific compounds include metal compounds such as salicylic acid, naphthoic acid and dicarboxylic acid as negative compounds, polymer type compounds having sulfonic acid and carboxylic acid in the side chain, boron compounds, urea compounds, silicon compounds, currys arenes and the like. Available, quaternary ammonium salt as positive system,
A polymeric compound having the quaternary ammonium salt in the side chain,
Guanidine compounds and imidazole compounds are preferably used. The charge control agent was 0.
5 to 10 parts by weight is preferable. However, the addition of a charge control agent in the present invention is not essential, in the case of using the two-component developing method, utilizing the triboelectric charging with the carrier, even in the case of using the non-magnetic one-component blade coating developing method. It is not always necessary to include the charge control agent in the toner by utilizing the triboelectric charging with the member or the sleeve member.

As the polymerization initiator used in the present invention, for example, 2,2'-azobis- (2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile,
1,1'-azobis (cyclohexane-1-carbonitrile), 2,2'-azobis-4-methoxy-2,4-
Azo-based polymerization initiators such as dimethyl valeronitrile and azobisisobutyronitrile; benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, 2,4-
Peroxide type polymerization initiators such as dichlorobenzoyl peroxide and lauroyl peroxide are used. The amount of the polymerization initiator added varies depending on the desired degree of polymerization, but it is generally used in an amount of 0.5 to 20% by weight based on the monomer. Although the kind of the initiator varies slightly depending on the polymerization method, it may be used alone or in combination with reference to the 10-hour half-life temperature.

In order to control the degree of polymerization, known cross-linking agents, chain transfer agents, polymerization inhibitors and the like may be further added and used.

When suspension polymerization is used in the toner production method of the present invention, the dispersant used is, for example, an inorganic oxide such as tricalcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, calcium carbonate. , Magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate, bentonite, silica, alumina, magnetic material, ferrite and the like.
As the organic compound, polyvinyl alcohol, gelatin, methyl cellulose, methyl hydroxypropyl cellulose, ethyl cellulose, sodium salt of carboxymethyl cellulose, starch and the like are used by dispersing in an aqueous phase. It is preferable to use 0.2 to 10.0 parts by weight of these dispersants with respect to 100 parts by weight of the polymerizable monomer.

As these dispersants, commercially available ones may be used as they are, but in order to obtain dispersed particles having a fine and uniform particle size, an inorganic compound can be formed in a dispersion medium under high speed stirring. . For example, in the case of tricalcium phosphate, a dispersant suitable for the suspension polymerization method can be obtained by mixing an aqueous sodium phosphate solution and an aqueous calcium chloride solution under high speed stirring. Further, 0.001 to 0.1 part by weight of a surfactant may be used in combination for making the dispersant fine. Specifically, commercially available nonionic, anionic, and cationic surfactants can be used. For example, sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate,
Sodium oleate, sodium laurate, potassium stearate, calcium oleate and the like are preferably used.

The method for producing a toner according to the present invention is characterized in that in the mixing step, a releasing agent comprising a low-softening substance in a monomer,
A colorant, a charge control agent, a polymerization initiator and other additives were added and uniformly dissolved or dispersed, and the monomer composition was dispersed with a dispersion stabilizer in an aqueous medium in the subsequent granulation step. Disperse by high shear in granulator. When the particles of the monomer composition have the desired toner particle size, the granulation is stopped. Thereafter, in the polymerization step, stirring may be performed to the extent that the particle state is maintained and the particles are prevented from settling due to the action of the dispersion stabilizer. The polymerization temperature is set to 40 ° C. or higher, generally 50 to 90 ° C. to carry out the polymerization. Further, the temperature may be raised in the latter half of the polymerization reaction, and further, in order to remove unreacted polymerizable monomers, by-products and the like, the distillation reaction is performed in the latter half of the polymerization reaction or after completion of the reaction, and a partial water system is used. The medium may be distilled off. After the completion of the polymerization reaction, the produced toner particles are collected by washing and filtration and dried. In the suspension polymerization method, usually monomer system 1
It is preferable to use 300 to 3000 parts by weight of water as a dispersion medium with respect to 00 parts by weight.

The external additive used for the purpose of imparting various toner characteristics is preferably a particle diameter of 1/10 or less of the weight average diameter of the toner particles from the viewpoint of durability when added to the toner. . The particle size of the additive means the average particle size thereof obtained by observing the surface of the toner particles with an electron microscope. Examples of the external additive include metal oxides (aluminum oxide, titanium oxide, strontium titanate, cerium oxide, magnesium oxide, chromium oxide,
Tin oxide, zinc oxide, etc.), nitride (silicon nitride, etc.),
Carbides (silicon carbide, etc.), metal salts (calcium sulfate,
Barium sulfate, calcium carbonate, etc.), fatty acid metal salts (zinc stearate, calcium stearate, etc.),
Carbon black, silica, etc. are used.

These external additives are used in an amount of 0.01 to 10 parts by weight, preferably 0.05 to 5 parts by weight, based on 100 parts by weight of the toner particles. These external additives are
They may be used alone or in combination. Those subjected to a hydrophobic treatment are more preferable.

The average particle size and particle size distribution of the toner can be measured by various methods such as Coulter Counter TA-II type or Coulter Multisizer (manufactured by Coulter Co.). In the present invention, Coulter Counter TA-
An interface (made by Nikkaki) and a PC98 that outputs a number distribution and a volume distribution using a type II (made by Coulter)
01 Connect a personal computer (made by NEC),
As the electrolytic solution, a 1% NaCl aqueous solution is prepared using first grade sodium chloride. For example, ISOTON R-II (manufactured by Coulter Scientific Japan) can be used. As the measuring method, the electrolytic aqueous solution 100 to 150 is used.
0.1 to 5 ml of a surfactant, preferably an alkylbenzene sulfonate, is added as a dispersant to ml, and 2 to 20 mg of a measurement sample is further added. The electrolytic solution in which the sample was suspended was subjected to a dispersion treatment for about 1 to 3 minutes with an ultrasonic disperser, and the volume and number of toner particles of 2 μm or more were measured using a 100 μm aperture as an aperture with the Coulter Counter TA-II type. The volume distribution and number distribution were calculated. Then, a volume-based weight-average particle diameter (D4: the median value of each channel is used as a representative value of the channels) was determined from the volume distribution.

[0059]

EXAMPLES The present invention will be described in more detail with reference to specific production methods, examples and comparative examples, but the present invention is not limited thereto.

The inner wall portion was made of stainless steel (SUS304), and 15.0 parts by weight of ion-exchanged water and 0.1M-Na ₃ PO _{4 were} added to a granulation container having a jacket portion for temperature adjustment.
After adding 14.4 parts by weight of the aqueous solution and heating to 60 ° C.,
Using Claremix (M Technique Co., Ltd.), 5
It was stirred at 000 rpm. 1.0M-CaCl
2.18 parts by weight of ₂ aqueous solution was gradually added to Ca ₃ (P
An aqueous medium containing O ₄ ) ₂ was obtained. While adjusting the degree of vacuum in the jacket of this granulation container to about 25 kPa, high-pressure saturated steam was supplied into the jacket to control the jacket so that it was filled with saturated steam, and the liquid temperature was 60 ° C.
Controlled.

On the other hand,     Styrene (monomer) 5.28 parts by weight     n-Butyl acrylate 1.12 parts by weight     C. I. Pigment Blue 15: 3 (colorant) 0.5 part by weight     Metal salicylate compound (charge control agent) 0.08 parts by weight     Saturated polyester (polar resin) 0.3 parts by weight     (Acid value 10 mg kOH / g, peak molecular weight; 7500 Mn; 6000)     Ester wax (melting point 70 ° C) (release agent) 1.0 part by weight

The above materials were placed in a mixing vessel (with a stirrer) having an inner wall portion coated with a fluororesin and having a jacket portion for temperature control, heated to 60 ° C., and uniformly dissolved.
Dispersed. 0.3 parts by weight of the polymerization initiator 2,2′-azobis (2,4-dimethylvaleronitrile) was dissolved in this to prepare a polymerizable monomer composition. While adjusting the vacuum degree in the jacket of this mixing container to about 25 kPa,
High-pressure saturated steam was supplied into the jacket, and the jacket was filled with saturated steam to control the liquid temperature to 60 ° C.

The contents of the mixing container (polymerizable monomer composition) were put into a granulation container having the prepared aqueous medium,
At 60 ° C. under N ₂ atmosphere, the inside of the granulating vessel was stirred at 5000 rpm (the peripheral speed of the tip of the blade: 24.9 m).
/ S, d / D: 0.27), and the polymerizable monomer composition was granulated. Then, when the particles of about 7 μm became the main particles (granulation time: 6 minutes), the granulation was stopped.

The polymerizable monomer composition which has been granulated is transferred to a polymerization container having a glass lined inner wall and a jacket for temperature control. While adjusting the vacuum degree in the jacket of the polymerization container to about 25 kPa,
Supplying high-pressure saturated steam into the jacket, controlling the jacket to be filled with saturated steam, controlling the liquid temperature to 60 ° C., stirring under a N ₂ atmosphere with paddle stirring blades, The polymerization reaction was carried out for 5 hours. After that, while adjusting the degree of vacuum in the jacket of the polymerization vessel to about 60 kPa, high-pressure saturated steam was supplied into the jacket to control the jacket to be filled with saturated steam, and the liquid temperature was 80 ° C. Control under N ₂ atmosphere,
While stirring with a paddle stirring blade, the polymerization reaction was continued for another 3 hours.

After completion of the polymerization reaction, residual monomers were distilled off under reduced pressure, and after cooling, hydrochloric acid was added to dissolve calcium phosphate, followed by filtration, washing with water and drying to obtain colored suspended particles. When the particle size distribution of the colored suspended particles was measured with a Coulter Multisizer, the weight average diameter was 6.7 μm and 4 μm.
The following particles were 17.0% by number and particles of 10.1 μm or more were 3.0% by volume, and the particle size distribution was very sharp. Observation of the toner layer surface confirmed a core / shell structure.

BE was added to 100 parts by weight of the obtained particles.
Hydrophobic silica having a specific surface area according to the T method of 200 m ² / g was externally added to obtain a suspension-polymerized toner. Acrylic-coated ferrite carrier 9 was added to 5 parts by weight of this toner.
A developer was prepared by mixing 5 parts by weight. Using this developer, a full-color copying machine CLC500 modified by Canon was used to evaluate the continuous printing of 5,000 sheets. As a result, no offset occurred, no fog occurred, the image density was stable, and good images were obtained. Was given.

In addition, in the polymerization step, the amount of deposits in the polymerization vessel, the temperature rising time when the temperature was raised from 60 ° C. to 80 ° C., and the temperature stability were evaluated, and the evaluation results are shown in Table 1. .

The evaluation criteria are as follows. [Adhesion in Polymerization Container] A: 10 g or less B: 11 to 20 g C: 21 to 50 g D: 51 g or more [heating time] This is the time (minutes) required when the temperature was raised from 60 ° C to 80 ° C. [Temperature stability] This is the fluctuation range of the temperature during the polymerization reaction while maintaining the temperature constant in the polymerization step.

(Comparative Examples 1 and 2) As a means for heating and keeping the temperature constant, instead of using steam below atmospheric pressure, high-pressure saturated steam or hot water with an absolute pressure of 200 kPa was used, but in Example 1 A developer was prepared in the same manner as in. The hot water temperature when hot water was used was set to be 5 ° C higher than the control temperature of the contents.

In addition, in the polymerization process, the amount of the deposits in the polymerization tank, the temperature rising time when the temperature was raised from 60 ° C. to 80 ° C., and the temperature stability were evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0071]

[Table 1]

When steam having an absolute pressure lower than the atmospheric pressure is used as a means for keeping the heating and the temperature constant, the adhesion in the container does not occur, the temperature responsiveness is excellent, and the heating time is short. The cost in can also be suppressed. On the other hand, high-pressure steam has a lot of adhesion in the tank and lacks temperature stability. Further, when hot water is used, it is excellent in adhesion in the tank, but the temperature rising time is slow and the temperature responsiveness is poor. Further, a large amount of capital investment is required for the hot water tank and the like, and the loss of heat is also large, so that the manufacturing cost is inferior to the case of using steam having an absolute pressure lower than atmospheric pressure.

Example 2 A developer was prepared in the same manner as in Example 1 except that the materials for producing toner particles and the aqueous medium of Example 1 were used in an amount of 8 times each.

Comparative Example 3 A developer was prepared in the same manner as in Example 2 except that hot water was used instead of steam below atmospheric pressure as a means for keeping heating and temperature constant. The temperature of the hot water is 5 ° C below the control temperature of the contents.
It was set to a high temperature.

When hot water is used as a means for heating and keeping the temperature constant, if the production amount is increased, a larger hot water tank is required, the investment amount is increased, and the heat loss is increased. Therefore, the production cost is increased. Greatly increased. On the other hand, when water vapor whose absolute pressure is lower than atmospheric pressure is used,
Even if the production amount increases, the increase in production cost can be suppressed.

[0076]

INDUSTRIAL APPLICABILITY As described above, the production method of the present invention is superior in production cost to the production of a toner for developing an electrostatic image by the polymerization method as compared with the conventional methods, and the inner wall portion of the container in each production process is excellent. It is possible to reduce the adhesion of the contents to the.

[Brief description of drawings]

FIG. 1 is a flowchart of a toner manufacturing method of the present invention.

FIG. 2 is a schematic explanatory view showing a specific example of an apparatus used in a polymerization step.

[Explanation of symbols]

1 Polymerization container 2 Vacuum generator 3 stirrer 4 tank jacket 5,6 control valve 7 Temperature detector 8 control valves 9 High-pressure steam supply device 10 computers 11 Cooling means 12,21 Vacuum generator 13,22 Tank jacket 14,15,23,24 Control valve 16,25 Temperature detector 17,26 Control valve 18,27 High pressure steam supply means 19,28 Computer 20,29 Cooling means

   ─────────────────────────────────────────────────── ─── Continued front page       (56) References JP-A-61-85426 (JP, A)                 JP-A-9-328503 (JP, A)                 JP-A-9-258479 (JP, A)                 JP-A-8-281096 (JP, A)                 JP-A-6-159947 (JP, A)                 JP-A-8-314195 (JP, A)                 JP-A-8-305074 (JP, A)                 JP-A-7-238103 (JP, A)                 JP-A-3-43402 (JP, A)                 JP-A-1-315336 (JP, A)                 JP-A 1-277254 (JP, A)                 JP-A-5-15774 (JP, A)                 Actual Kaihei 4-87736 (JP, U)                 Actual Kaihei 4-122640 (JP, U)                 Chemistry Handbook Basic Edition Revised 4th Edition, Maruzen               Ltd., September 30, 1993, II-12               Page 3, Table 8.30

Claims (13)

(57) [Claims] 1. A mixing step for preparing a polymerizable monomer composition containing at least a polymerizable monomer and a colorant, wherein the polymerizable monomer composition is dispersed in an aqueous medium by high shearing force. A toner having a granulation step of granulating particles of a polymerizable monomer composition and a polymerization step of polymerizing a polymerizable monomer in particles of the polymerizable monomer composition to produce toner particles a manufacturing method, the polymerization step have a jacket, inner wall Gurasurainin
Conducted in a container that is grayed, while adjusting the degree of vacuum in the jacket, by supplying the high-pressure steam into the jacket, the liquid temperature in the vessel are temperature controlled, and the vacuum in the jacket The method for producing an electrostatic charge image developing toner, wherein the degree is adjusted to 10 to 90 kPa. 2. The liquid temperature in the container is controlled by performing the mixing step in a container having a jacket, and by supplying high-pressure steam into the jacket while adjusting the degree of vacuum in the jacket. The method for producing a toner for developing an electrostatic charge image according to claim 1. 3. The granulating step is performed in a container having a jacket, and the liquid temperature in the container is controlled by supplying high-pressure steam into the jacket while adjusting the degree of vacuum in the jacket. The method for producing a toner for developing an electrostatic charge image according to claim 1, which is characterized in that. 4. The method for producing a toner for developing an electrostatic charge image according to claim 1, wherein the polymerizable monomer composition contains a styrene-based monomer. . 5. The method for producing a toner for developing an electrostatic charge image according to claim 1, wherein the polymerizable monomer composition contains a polar resin. 6. The method for producing a toner for developing an electrostatic charge image according to claim 1, wherein the polymerizable monomer composition contains a polymerization initiator. 7. The degree of vacuum in the jacket is 10 to 80.
7. The method for producing a toner for developing an electrostatic image according to claim 1, wherein the toner has a kPa. 8. The toner particles, core / claims 1 to 7 method of manufacturing a toner according to any one of characterized in that it has a shell structure. 9. The method for producing a toner for developing an electrostatic charge image according to claim 8 , wherein the main component of the core part is a low softening point substance. 10. A high-pressure steam supplied within the jacket, claims 1 to 9, characterized in that the saturated steam
5. The method for producing a toner for developing an electrostatic charge image according to any one of 1. 11. The temperature of water vapor in the jacket is 45.
Method for producing a toner according to any one of claims 1 to 10, characterized in that it is to 90 ° C.. 12. within the jacket, a manufacturing method of the toner according to any one of claims 1 to 11, characterized in that it is filled with saturated steam. 13. The polymerization process The production method of the toner for electrostatic image development according to any one of claims 1 to 12, characterized in that is carried out at a liquid temperature of 50 to 90 ° C..