JPH08314195A - Production of electrostatic charge image developing toner - Google Patents

Abstract

PURPOSE: To provide a method for producing toners which efficiently produces the toners having a sharp grain size distribution by easily controlling their average particle sizes in production of the electrostatic charge image developing toners by a polymn. method. CONSTITUTION: This process for producing the electrostatic charge image developing toners from a polymerizable monomer compsn. by the polymn. method includes the toner particle granulating stage and polymerizing stage. The toner particle granulating stage is provided for incorporating the polymerizable monomer into a dispersion stabilizer and dispersing this stabilizer into a liquid dispersion medium substantially incompatible with the polymerizable monomer. An agitating device 2 having high shearing force is included in a granulating vessel 1. This agitating device 2 has agitating blades rotating at a high speed and an agitating chamber and is so constituted that the liquid fluid is ejected downward from this agitating chamber.

Description

Detailed Description of the Invention

[0001]

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

[0002]

BACKGROUND OF THE INVENTION Electrophotography is described in US Pat. No. 2,297,
A number of methods are known as described in Japanese Patent No. 691. Generally, a photoconductor made of a photoconductive substance is used, and an electric latent image is formed on the photoconductor by various means. Then, the latent image is developed with toner to form a visible image, and the toner image is transferred to a transfer material such as paper as necessary, and then the toner image is fixed on the transfer material by heat or pressure. To obtain a copy or a printed matter. 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 coloring agent comprising a dye or a pigment is melt-kneaded in a thermoplastic resin and uniformly dispersed, and then finely pulverized by a fine pulverizer, and the finely pulverized product is classified by a classifier to obtain a desired particle size. Manufactured to have.

While this method of manufacture can produce fairly good toners, it has certain limitations, namely the range of choice of toner materials. For example, the toner coarse powder must be sufficiently brittle and can be finely pulverized in an economically feasible manufacturing apparatus. However, if the toner coarse powder is made brittle in order to satisfy these requirements, when the toner coarse powder is actually finely pulverized at a high speed, the particle size range of the formed particles tends to be wide, and particularly the relatively large size. There is a problem that the fine particles are contained in the finely pulverized material in proportion.

Further, the toner obtained from such a material having high brittleness is likely to undergo further fine pulverization or pulverization in a developing device such as a copying machine. Further, in this method, it is difficult to completely 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, a color mixing property or Careful attention must be paid to the dispersion of the colorant, since it may cause poor transparency. In addition, the exposure of the colorant to the fracture surface of the crushed particles may cause fluctuations in the developing characteristics.

On the other hand, in order to overcome the problems of the toner due to the pulverization method, Japanese Patent Publication No. 36-10231, Japanese Patent Publication No. 43-10799 and Japanese Patent Publication No. 51-14895.
Various polymerization toners and methods for producing the same have been proposed, including suspension polymerization toners disclosed in Japanese Patent Laid-Open Publications and the like. For example,
In the suspension polymerization method toner, 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 obtain a monomer composition. Then, the monomer composition is a continuous phase containing a dispersion stabilizer,
For example, toner particles having a desired particle diameter are obtained by dispersing them in an aqueous phase using a suitable stirrer and simultaneously carrying out a polymerization reaction.

In this method, since the pulverizing step is not included at all, the toner does not need to be brittle, a soft material can be used as the resin, and the colorant is not exposed on the particle surface. However, there is an advantage that a toner having a uniform triboelectrification property 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 a high yield. Further, since a large amount of a low softening point substance can be included in the toner as a release agent, there is an advantage that the obtained toner has excellent offset resistance.

[0008]

However, due to the characteristics of the manufacturing method, the toner produced by the polymerization method is very difficult to obtain in order to obtain toner particles having a desired particle size and a sharp particle size distribution in the granulating step. Is important to. Conventionally, various stirring devices, emulsifying devices and the like have been used in this granulation step, but there is a problem that it is very difficult to obtain polymer particles having a fine, uniform and sharp particle size distribution. In addition, in this granulation step, the liquid may stay in the granulation container, and in such a case, the granulated droplets will coalesce, resulting in polymer particles having a broad particle size distribution. There is a problem that it will end up.

Therefore, an object of the present invention is to provide a method for producing a toner for producing an electrostatic charge image developing toner by a polymerization method, which makes it easy to control the average particle size and efficiently produces a toner having a sharp particle size distribution. To provide. or,
Another object of the present invention is to provide a method for producing a toner having excellent fixability.

[0010]

The above object can be achieved by the present invention described below. That is, the present invention is a method for producing a toner, in which a polymerizable monomer composition is produced by a polymerization method including a toner particle granulation step and a polymerization step, wherein the toner particle granulation step is performed in a granulation container. A step of granulating by dispersing a polymerizable monomer in a liquid dispersion medium containing a dispersion stabilizer and substantially incompatible with the polymerizable monomer composition, wherein the granulation is performed. A stirring device having a high shearing force is provided in the container, the stirring device is provided with a stirring blade and a stirring chamber that rotate at high speed, and the liquid fluid is jetted downward from the stirring chamber. A method for producing an electrostatic charge image developing toner characterized in that it is configured.

[0011]

As a result of intensive studies, the present inventors granulated the polymerizable monomer composition in the granulation container to obtain droplet particles having a sharp particle size distribution. It was found that the jetting direction from the nozzle, that is, the flow pattern of the liquid in the granulation container is very important. The method for producing the toner for developing an electrostatic image of the present invention is based on such knowledge.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be described in more detail with reference to preferred embodiments. A schematic sectional view of a preferable granulating apparatus used in the present invention is shown in FIGS. 1 and 2. In FIG. 1, 1 is a granulation container, 2 is a stirring device, 3 is a stirring shaft for driving the stirring device, and 7 is a jacket.
2 is an enlarged cross-sectional view of the stirring device in FIG. 1, 4 is a stirring blade, 5 is a screen, and 6 is a stirring chamber.

In such a granulating and stirring device, the dispersion liquid comprising the polymerizable monomer composition and the liquid dispersion medium enters the stirring chamber 6 from the upper part of the stirring device 2, and the stirring blade 4 and the screen rotating at high speed. After being agitated by the strong shearing force, impact and turbulent flow generated with No. 5, micron-order monomer composition particles are formed, they are jetted into the granulation container from the gap of the screen. In the stirrer having the above structure, the shape of the stirring blade, the mesh diameter of the screen, and the gap between the stirring blade and the screen can be changed, and the viscosity of the monomer composition and the final desired monomer composition It is possible to use a preferable one depending on the particle size and the like.

In the granulation step, in order to carry out the granulation at a certain temperature, the granulation container usually has a jacket structure, and hot water or steam, and if necessary, cold water is flown into the jacket so that the inside of the container is filled. It is preferable to perform temperature control. In such a granulation and agitation device, the fluid flow is jetted downward from the upper part. In this case, the polymerizable monomer composition is fed into the stirring chamber very efficiently, and the monomer composition particles having a sharp particle size distribution are obtained. When the discharge directions are opposite, that is,
In the method in which the fluid is ejected from the lower part of the container to the upper part, the fluid is ejected to the upper part of the container, so that the fluid is diffused to the upper part of the container and it is difficult to form a uniform fluid flow.

As a means for solving the problem, there is used a method in which a baffle plate or the like is attached so as to oppose the jetting direction and the flow is regulated. However, in such a method, since the monomer composition violently collides with the baffle plate, very fine particles may be generated at that time, or the generated particles may be re-aggregated, and the particle size of the obtained particles may be increased. There is a problem that the distribution becomes wide.

On the other hand, the present invention improves such a problem by making the flow direction of the fluid downward from the upper part of the container. Moreover, by advancing the flow direction from the upper side to the lower side, the adhesion of the monomer composition to the inside of the container can be reduced, which is also very preferable in terms of maintenance. Furthermore, in general, when granulating, the polymerizable monomer composition is charged into a granulation container charged with a liquid dispersion medium that is incompatible with the monomer composition, and the mixture is dispersed to granulate. In this case, it is important that the polymerizable monomer composition is sufficiently mixed in the dispersion medium at that time. However, as in the present invention, the direction of fluid flow should be downward from the upper part of the container. It can be thrown in very smoothly.

The particle size of the obtained particles can be controlled by
Usually, the amount of the dispersion stabilizer used and the number of rotations of the stirring blade are used. As a result of intensive studies, the peripheral speed of the stirring blade is preferably controlled at 15 to 30 m / sec at the tip of the blade in terms of sharpening the particle size distribution of the obtained particles. At a peripheral speed of less than 15 m / sec, it is difficult to reduce the droplet particle size, and at 30 m / sec or more, a large number of extremely fine particles unsuitable for use as a toner are generated, resulting in a particle size distribution. Becomes wide. Furthermore, it is more preferable to control the tip peripheral speed of the blade to 20 to 30 m / sec.

The diameter d of the stirring blade and the inner diameter D of the granulation container
The value of d / D, which is the ratio of, is a very important factor in achieving uniform agitation in the vessel. That is, when d / D is small, sufficient agitation cannot be obtained, and when d / D is too large, the collision force with the inner wall of the container becomes large and turbulent flow is generated, which is not preferable. Therefore, as a result of examination by the present inventors, when the stirring shaft of the stirring blades contributing to granulation as shown in FIG. 1 is one, d / D is in the range of 0.1 to 0.3. It has been found that the range of 0.2 to 0.3 is more preferable, and the range of 0.2 to 0.3 is more preferable.

The granulating stirrer used in the method for producing a toner of the present invention is configured so that the axis of the stirring shaft of the stirrer can be tilted with respect to the central axis of the granulating container as shown in FIG. More preferable performance can be obtained. By inclining the stirring shaft, it becomes possible to reduce the entrainment of bubbles. When bubbles are mixed, even if the stirring blade applies energy to the object to be treated, the bubbles themselves contract to absorb the energy and reduce the ability to atomize the object to be treated. For this reason, it is preferable to use it by inclining it as shown in FIG.

Further, as shown in FIG. 3, the anchor wing 9
When used in combination with, the convection of heat in the container is improved, and more uniform droplet particles can be generated. Furthermore, by using it together with the anchor blade, it is possible to suppress the vortex flow in the container, and it is possible to achieve uniform diffusion. Also in the apparatus configuration of FIG. 3, it is preferable that the blade tip peripheral speed range and d / D range are the same as those of the apparatus shown in FIG.

An example of another granulating apparatus used in the present invention is shown in FIGS. 4 and 5. In FIG. 4, 1 is a granulation container, 8
Is a stirring device, 9 is an anchor blade, and in FIG.
Is a stirring blade, 11 is a stator, 12 is a stirring shaft, 1
3 is a stirring chamber. In such a granulation stirrer, a dispersion liquid comprising a polymerizable monomer composition and a liquid dispersion medium,
The mixture enters the stirring chamber 13 from the upper part of the stirring device 8 and is stirred by the strong shearing force, shock and turbulence generated between the stirring blade 10 rotating at high speed and the stator 11 to form a monomer composition particle of micron order. Then, it is jetted from the lower part of the stirring chamber into the granulation container.

In the stirrer having the above construction, the shape of the stirring blade, the shape of the stator, and the gap between the stirring blade and the stator can be changed, and the viscosity of the monomer composition and the final desired monomer composition can be changed. Depending on the particle size of the product and the like, a suitable form is used. The apparatus of FIG. 4 is provided with two agitators, but this may be one if necessary. Also, the anchor blade as shown in FIG. 4 may be used or not as needed. When the stirring shaft of the stirring device that contributes to the granulation is two as shown in FIG. 4, the preferable d / D range is 0.05 to 0.2, and more preferably 0.1 to 0.2. It is in the range of 0.2.

It is preferable that the apparatus used in the present invention is such that the rotating direction of the stirring blade can be rotated in both forward and reverse directions. This is very effective at the time of cleaning the inside of the agitator because the discharge directions are different by making the directions opposite. That is, the deposits and scale in the dead space in the stirring chamber can be easily removed by reversing the rotation.

As a result of further intensive studies on the above-mentioned apparatus preferably used in the manufacturing method of the present invention, FIG.
It was also found that the apparatus having the configuration shown in FIG. 3 can obtain particles with higher dispersion and a sharp particle size distribution. This is because in the apparatus of FIGS. 1 and 3, the high-speed jet flow is ejected through the slits formed in the screen, and the shearing force at that time is much stronger than that of the apparatus of FIG. Further, in the case of the production of a toner having a core / shell structure in which the shell portion is formed by polymerization and having both fixing property and blocking resistance,
It is necessary that the low softening point substance be present in the respective toner particles in the same proportion, and control of the particle size distribution during granulation is also important in this respect. In the production method of the present invention, since the particle size distribution of droplet particles of the polymerizable monomer composition at the time of granulation can be made sharp, such a problem can be solved.

Further, as the main component of the core part, a low softening point substance is preferable, and a compound having a main component maximum peak value measured in accordance with ASTM D3418-8, which is 40 to 90 ° C., is preferable. When the maximum peak is less than 40 ° C., the self-aggregating force of the low softening point substance becomes weak, and as a result, the high temperature offset property at the time of transferring the toner image becomes weak, which is not preferable. On the other hand, if the maximum peak exceeds 90 ° C., the fixing temperature of the toner becomes high, which is not preferable. Further, if the temperature of the maximum peak value is high, a substance having a low softening point is mainly precipitated during granulation, which hinders the suspension system, which is not preferable.

In the present invention, the temperature of the maximum peak value of the low melting point substance is measured by, for example, DS manufactured by Perkin Elmer Co.
C-7 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 / mi.
n. Was measured.

As the low-melting substance, specifically, paraffin wax, polyolefin wax, Fischer-Tropish wax, amide wax, higher fatty acid, ester wax and derivatives thereof or graft / block compounds thereof may be used. I can. The low softening point substance is preferably added to the toner in an amount of 5 to 30% by weight. If the amount added is less than 5% by weight, sufficient toner fixability cannot be obtained. If the amount added exceeds 30% by weight, toner particles are likely to coalesce with each other during granulation even in the production by the polymerization method, resulting in particle size distribution. It is not suitable for the present invention because a toner having a wide range is easily generated.

As a specific method for encapsulating the low softening point substance, the polarity of the material in the aqueous medium is set to be smaller for the low softening point substance than for the main monomer, and a small amount of resin having a large polarity or By adding a monomer, a toner having a so-called core / shell structure in which a low softening point substance is coated with an outer shell resin can be obtained. Toner particle size distribution control and particle size control are performed by changing the type and amount of the poorly water-soluble inorganic salt or dispersant that acts as a protective colloid, and mechanical device conditions such as the peripheral speed of the rotor and the number of passes. The toner of the present invention having a predetermined particle size distribution can be obtained by controlling the stirring conditions such as the shape of a stirring blade, the shape of a container, or the solid content concentration in an aqueous solution.

A specific method for measuring the tomographic plane of the toner in the present invention is obtained by sufficiently dispersing the toner in an epoxy resin which is curable at room temperature and then curing it in an atmosphere at a temperature of 40 ° C. for 2 days. A cured product of ruthenium tetraoxide,
After dying with osmium tetroxide as needed, a microtome equipped with diamond teeth was used to cut out flaky samples and observe the tomographic morphology of the toner using a transmission electron microscope (TEM). . 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.

Examples of the polymerizable monomer used in the present invention include styrene-based monomers such as styrene, o (m-, p-)-methylstyrene, m (p-)-ethylstyrene; (meth) acryl. Methyl acid, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, octyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, (meth) acrylic acid (Meth) acrylate monomers such as behenyl, 2-ethylhexyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate; butadiene, isoprene, cyclohexene, (meth) acrylonitrile An ene-based monomer such as acrylic acid amide is preferably used.

These may be used alone or generally in the publication Polymer Handbook Second Edition III-P 139-192 (Joh.
nWiley & Sons) Theoretical glass transition temperature (T
g) is used by appropriately mixing the monomers so that it shows 40 to 80 ° C. When the theoretical glass transition temperature is lower than 40 ° C., problems occur in storage stability of the toner and durability stability of the developer. On the other hand, when the theoretical glass transition temperature 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.

The molecular weight of the outer shell resin of the toner having a core / shell structure is measured by GPC (gel permeation chromatography). As a specific method for measuring GPC, the toner is previously extracted by using a Soxhlet extractor with a toluene solvent for 20 hours, and then the toluene is distilled off with a rotary evaporator. Further, the low softening point substance is dissolved. Sample obtained by adding an organic solvent that does not dissolve the shell resin, for example, chloroform, and thoroughly washing, and then filtering the solution soluble in THF (tetrahydrofuran) with a solvent-resistant membrane filter having a pore size of 0.3 μm. Using 150C manufactured by Waters,
The column configuration is Showa Denko A-801, 802, 803,
804, 805, 806, and 807 can be connected, and the molecular weight distribution can be measured using a calibration curve of standard polystyrene resin. The number average molecular weight (Mn) of the obtained resin component is 5,000.
~ 1,000,000, weight average molecular weight (Mw)
And the number average molecular weight (Mn) ratio (Mw / Mn) is 2 to 1
Outer shell resins exhibiting 00 are preferred for the present invention.

In the present invention, when a toner having a core / shell structure is produced, 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,
Epoxy resin is 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 it contains a polar resin having an unsaturated group, a cross-linking reaction occurs with the monomer forming the outer shell resin layer, and in particular, it has an extremely high molecular weight as a full-color toner, which is not suitable for mixing four-color toner. It is not preferable because it is disadvantageous.

Further, in the present invention, an outermost shell resin layer may be further provided on the surface of the toner. The glass transition temperature of the outermost shell resin layer is designed to be equal to or higher than the glass transition temperature of the outer shell resin layer in order to further improve the blocking resistance, and further, it is crosslinked so as not to impair the fixing property. Is preferred. Further, it is preferable that the outermost shell resin layer contains a polar resin and a charge control agent in order to improve chargeability.

The method for providing the outermost shell layer is not particularly limited, but the following method may be mentioned, for example. In the latter half of the polymerization reaction or after the completion of the polymerization, if necessary, a monomer in which a polar resin, a charge control agent, a cross-linking agent, etc. are dissolved or dispersed is added to the reaction system and adsorbed on the polymer particles, and a polymerization initiator is added. How to carry out polymerization. If necessary, polar resin, charge control agent, emulsion-polymerized particles or soap-free polymerized particles composed of a monomer containing a cross-linking agent, etc. are added to the reaction system to cause aggregation on the surface of the polymerized particles, and further as necessary. Method of fixing by heat. A method of mechanically adhering emulsion-polymerized particles or soap-free polymerized particles composed of a monomer containing a polar resin, a charge control agent, a cross-linking agent, etc., to the surface of the toner particles in a dry manner, if necessary.

The colorant used in the present invention is carbon black as a black colorant, a magnetic material, and the following yellow / magenta / cyan colorants, which are toned black. As the yellow colorant, compounds represented by condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds and allylamide compounds are used. Specifically, C.I.
I. Pigment Yellow 12, 13, 14, 15, 1
7, 62, 74, 83, 93, 94, 95, 109, 1
10,111,128,129,147,168 etc. are used suitably.

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. Pigmentlet 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 used suitably.

As the cyan colorant used in the present invention, 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 are preferably used. These colorants may be used alone or in combination, and may be used in the state of 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, weather resistance, 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 4 per 100 parts by weight of the resin.
It is used by adding 0 to 150 parts by weight.

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. Further, a charge control agent which has no polymerization inhibitory property and has no solubilized product in an aqueous system is particularly preferable. Specific compounds include salicylic acid, naphthoic acid, metal compounds of dicarboxylic acid, sulfonic acid, polymer compounds having a carboxylic acid as a side chain, boron compounds, urea compounds, silicon compounds, currys arenes, etc. As a positive system, a quaternary ammonium salt, a high molecular compound having a side chain of the quaternary ammonium salt, a guanidine compound, an imidazole compound or the like can be preferably used.

The amount of the charge control agent used is preferably 0.5 to 10 parts by weight with respect to 100 parts by weight of the resin. However, in the present invention, the addition of the charge control agent is not essential, and in the case of using the two-component developing method, triboelectric charging with the carrier is utilized and even in the case of using the non-magnetic one-component blade coating developing method. By positively utilizing frictional charging with blade members and sleeve members,
It is not always necessary to include a charge control agent in the toner.

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 above-mentioned polymerization initiator added varies depending on the intended degree of polymerization, but is generally 0.5 with respect to the monomer.
It is used by adding up to 20% by weight. The type of initiator is
Although it varies slightly depending on the polymerization method, they are used alone or in combination with reference to the 10-hour half-life temperature. Further, in order to control the degree of polymerization, it is possible to further add and use a known crosslinking agent, chain transfer agent, polymerization inhibitor or the like.

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, or the like. Examples thereof include calcium carbonate, magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate, bentonite, silica, alumina, magnetic materials and ferrite.
As the organic compound, for example, polyvinyl alcohol, gelatin, methyl cellulose, methyl hydroxypropyl cellulose, ethyl cellulose, sodium salt of carboxymethyl cellulose, starch and the like are used after being dispersed or dissolved in the 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, the inorganic compound may be formed under high speed stirring in a dispersion medium. I can. 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, in order to make these dispersants finer, 0.001 to 0.1 part by weight of a surfactant may be used together. Specifically, commercially available nonionic, anionic and cationic surfactants can be used, and examples thereof include sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium laurate, and stearin. Potassium acid and calcium oleate are preferably used.

A specific method for producing a toner according to the present invention is carried out by adding a releasing agent consisting of a low-softening substance, a colorant, a charge control agent, a polymerization initiator and other additives to a monomer, homogenizer and ultrasonic wave. The monomer composition uniformly dissolved or dispersed by a disperser or the like is dispersed in a granulation container containing a dispersion stabilizer and having a stirrer as shown in FIGS. 1 to 5.

When the droplets of the monomer composition have the desired toner particle size, granulation is stopped. After that, by the action of the dispersion stabilizer, stirring may be performed to such an extent that the particle state is maintained and the particles are prevented from settling. 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, a part of the aqueous medium is distilled off in the latter half of the reaction or after the completion of the reaction. You may. After the reaction is completed, the produced toner particles are collected by washing and filtration and dried. In the suspension polymerization method, it is usually preferable to use 300 to 3,000 parts by weight of water as a dispersion medium with respect to 100 parts by weight of the monomer system.

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. As the external additive, for example, the following ones are used.

Metal oxides (aluminum oxide, titanium oxide, strontium titanate, cerium oxide, magnesium oxide, chromium oxide, tin oxide, zinc oxide, etc.), nitrides (silicon nitride, etc.), carbides (silicon carbide, etc.), metals Salts (calcium sulfate, barium sulfate, calcium carbonate, etc.), fatty acid metal salts (zinc stearate, calcium stearate, etc.), carbon black, silica, etc. These external additives are 0.01 to 100 parts by weight of the toner particles.
10 parts by weight is used, preferably 0.05 to 5 parts by weight. These external additives may be used alone, or
You may use together two or more. It is more preferable that each is subjected to a hydrophobic treatment.

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-II type ( Interface (made by Nikkaki) and PC9801 which outputs number distribution and volume distribution using Coulter
A personal computer (manufactured by NEC) is connected, and a 1% NaCl aqueous solution is prepared using an electrolyte solution of primary sodium chloride. For example, ISOTON R-II (manufactured by Coulter Scientific Japan Co.) can be used.

The measuring method is as follows:
A surfactant, preferably 0.1 to 5 mL of alkylbenzene sulfonate is added as a dispersant to ~ 150 mL, and 2 to 20 mg of a measurement sample is further added. The electrolyte solution in which the sample is suspended is subjected to a dispersion treatment for about 1 to 3 minutes by an ultrasonic disperser, and the Coulter counter TA-II type is used to form an aperture of 100 μm with an aperture of 2 μm.
The volume distribution and the number distribution of the toner having a size of m or more were measured to calculate the volume distribution and the number distribution. Then, the volume-based weight average particle diameter (D4: the median value of each channel is used as a representative value of the channels) and the weight variation coefficient (S4) obtained from the volume distribution according to the present invention, and the number obtained from the number distribution. The standard length average particle diameter (D1) and the length variation coefficient (S1) were determined. The image density is a numerical value obtained by measuring (5 mm square, 5 mm circle, solid black) with a Macbeth densitometer (manufactured by Macbeth Co.).

[0053]

EXAMPLES The present invention will be described in more detail with reference to specific examples and comparative examples. Example 1 To 2.28 kg of ion-exchanged water, 14.4 kg of 0.1 M Na ₃ PO ₄ aqueous solution was added, and after heating to 60 ° C., FIG.
It stirred at 5,000 rpm using the apparatus shown in FIG.
2.18 kg of 1.0 M-CaCl ₂ aqueous solution was gradually added to this to obtain an aqueous medium containing Ca ₃ (PO ₄ ) ₂ . Monomer Styrene 5.28 kg n-Butyl acrylate 1.12 kg Colorant C.I. I. Pigment Blue 15: 3 0.5 kg-Charge control agent metal salicylate compound 0.08 kg-Polar resin saturated polyester 0.3 kg (acid value 10, peak molecular weight: 7,500) -Release agent ester wax (melting point 70 ° C) ) 1.0 kg The above formulation was heated to 60 ° C and uniformly dissolved or dispersed using a dissolution tank (with a stirrer). 0.3 kg of 2,2'-azobis (2,4-dimethylvaleronitrile) as a polymerization initiator was dissolved in this to prepare a polymerizable monomer composition.

The above polymerizable monomer composition was put into the above aqueous medium, and the stirring device in the above granulation container was operated at 5,000 rpm (the peripheral speed of the tip of the blade: 60 ° C., N ₂ atmosphere).
The polymerizable monomer composition was granulated by stirring at 24.9 m / s and d / D: 0.27). The rotation direction of the stirring device was adjusted so that the flow direction of the fluid at this time was from the upper side to the lower side. Immediately after putting the polymerizable monomer composition into the granulation container, visually observing the inside of the granulation container from the upper inspection port, it was confirmed that the polymerizable monomer composition was smoothly mixed into the aqueous medium. I was able to do it.

Seven minutes after charging the polymerizable monomer composition, the stirring device was stopped and the composition was transferred to a polymerization tank equipped with a paddle stirring blade. In the polymerization tank, the reaction was carried out at 60 ° C. under N ₂ atmosphere for 10 hours while stirring with a paddle stirring blade. After completion of the polymerization reaction,
The residual monomer was 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 above-mentioned colored suspended particles was measured with a Coulter Multisizer, the weight average diameter was 6.5 μm.
m, 4μm or less particles are 25.0%, 10.1μm
The above particles were 5.0% by volume, and the particle size distribution was very sharp. Further, when the toner layer surface was observed, a core / shell structure was confirmed.

BE was added to 100 parts by weight of the obtained particles.
Hydrophobic silica having a specific surface area of 200 m ² / g by the T method was externally added to obtain a suspension polymerization toner 1. 95 parts by weight of an acrylic-coated ferrite carrier was mixed with 5 parts by weight of this toner to obtain a developer. Using this developer, continuous 5,000 sheets of images were evaluated by a modified full-color copying machine CLC500 manufactured by Canon, and no fog occurred, and the image density was stable, and good images were obtained.

Example 2 To 2.28 kg of ion-exchanged water, 14.4 kg of a 0.1 M Na ₃ PO ₄ aqueous solution was added, and the mixture was heated to 60 ° C.
It stirred at 5,000 rpm using the apparatus shown in FIG.
The stirring shaft of the stirring device in this granulation container was inclined by 10 ° with respect to the central axis of the granulation container. Also, the anchor wing is 50
Rotated at rpm. 2.18 kg of 1.0 M-CaCl ₂ aqueous solution was gradually added to this to obtain an aqueous medium containing Ca ₃ (PO ₄ ) ₂ .

A polymerizable monomer composition prepared in the same manner as in Example 1 was placed in this water-based dispersion medium preparation container, and the temperature was adjusted to 60 ° C.
In an N ₂ atmosphere, the stirring device in the granulation vessel was set to 5,000 rpm (vane tip peripheral speed: 24.9 m / s,
The mixture was stirred at d / D: 0.27) to granulate the polymerizable monomer composition. The rotation direction of the stirring device was adjusted so that the flow direction of the fluid at this time was from the upper side to the lower side. Immediately after putting the polymerizable monomer composition into the granulation container, visually observing the inside of the granulation container from the upper inspection port, it was confirmed that the polymerizable monomer composition was smoothly mixed into the aqueous medium. I was able to do it.

Five minutes after charging the polymerizable monomer composition, the stirring device was stopped and the composition was transferred to a polymerization tank equipped with a paddle stirring blade. In the polymerization tank, the reaction was carried out at 60 ° C. under N ₂ atmosphere for 10 hours while stirring with a paddle stirring blade. After completion of the polymerization reaction,
The residual monomer was distilled off under reduced pressure, and after cooling, hydrochloric acid was added,
After dissolving the calcium phosphate, filtration, washing with water and drying were performed to obtain colored suspended particles.

When the particle size distribution of the above colored suspended particles was measured with a Coulter Multisizer, the weight average particle size was 6.4 μm.
m, particles of 4 μm or less are 20.0% by number, 10.1 μm
The above particles were 3.0% by volume, and the particle size distribution was sharper than that of Example 1. Further, when the toner layer surface was observed, a core / shell structure was confirmed. The specific surface area by the BET method is 20 with respect to 100 parts by weight of the obtained particles.
Hydrophobic silica of 0 m ² / g was externally added to obtain a suspension polymerization toner 2. 95 parts by weight of an acrylic-coated ferrite carrier was mixed with 5 parts by weight of this toner to obtain a developer. Using this developer, continuous 5,000 sheets of images were evaluated by a modified full-color copying machine CLC500 manufactured by Canon, and no fog occurred, and the image density was stable, and good images were obtained.

Example 3 To 1.14 kg of ion-exchanged water, 7.2 kg of a 0.1 M Na ₃ PO ₄ aqueous solution was added, and after heating to 60 ° C., the apparatus (two stirring shafts) shown in FIG. 4 was used. It was used and stirred at 9,500 rpm. Also, the anchor blade was rotated at 50 rpm. 1.09 kg of 1.0 M-CaCl ₂ aqueous solution was gradually added to this to obtain an aqueous medium containing Ca ₃ (PO ₄ ) ₂ .

Monomer Styrene 2.64 kg n-Butyl acrylate 0.56 kg Colorant C.I. I. Pigment Blue 15: 3 0.25 kg-Charge control agent salicylate metal compound 0.04 kg-Polar resin saturated polyester 0.15 kg (acid value 10, peak molecular weight: 7,500) -Release agent ester wax (melting point 70 ° C) 0 0.5 kg The above formulation was heated to 60 ° C. and uniformly dissolved or dispersed using a dissolution tank (with a stirrer). As a polymerization start, 0.15 kg of 2,2'-azobis (2,4-dimethylvaleronitrile) was dissolved therein to prepare a polymerizable monomer composition.

The above polymerizable monomer composition was charged into the above aqueous medium, and the stirring device in the above granulation vessel was operated at 9,500 rpm (the peripheral speed of the tip of the blade: 60 ° C., N ₂ atmosphere).
The polymerizable monomer composition was granulated by stirring at 24 m / s and d / D: 0.14). The flow direction of the fluid at this time is
The rotation direction of the stirrer was adjusted so that it went from the upper side to the lower side. Immediately after putting the polymerizable monomer composition into the granulation container, visually observing the inside of the granulation container from the upper inspection port, it was confirmed that the polymerizable monomer composition was smoothly mixed into the aqueous medium. I was able to do it.

After 10 minutes from the introduction of the polymerizable monomer composition, the stirring device was stopped and the composition was transferred to a polymerization tank equipped with a paddle stirring blade. In the polymerization tank, the reaction was carried out at 60 ° C. under N ₂ atmosphere for 10 hours while stirring with a paddle stirring blade. After completion of the polymerization reaction,
The residual monomer was 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.

The particle size distribution of the above-mentioned colored suspended particles was measured with a Coulter Multisizer, and the weight average diameter was 7.0 μm.
m, particles of 4 μm or less are 30.0% by number, 10.1 μm
The above particles were 7.0% by volume, and the particle size distribution was sharp. Further, when the toner layer surface was observed, a core / shell structure was confirmed.

BE was added to 100 parts by weight of the obtained particles.
Hydrophobic silica having a specific surface area of 200 m ² / g by the T method was externally added to obtain a suspension polymerization toner 3. 95 parts by weight of an acrylic-coated ferrite carrier was mixed with 5 parts by weight of this toner to obtain a developer. Using this developer, continuous 5,000 sheets of images were evaluated by a modified full-color copying machine CLC500 manufactured by Canon, and no fog occurred, and the image density was stable, and good images were obtained.

Comparative Example 1 Using the aqueous dispersion medium and the polymerizable monomer composition prepared in the same manner as in Example 3, the apparatus shown in FIG. 4 was used to stir the fluid so that the flow of the fluid was from bottom to top. Rotation speed is set to 9,500 rpm (blade tip peripheral speed: 24 m / s, d /
The polymerizable monomer composition was granulated by stirring at D: 0.14). Immediately after putting the polymerizable monomer composition into the granulation container, the inside of the granulation container was visually inspected from the upper inspection port, and it was found that the polymerizable monomer composition was for a while (about several tens of seconds). It was found to be retained in the upper part of the inside.

After 10 minutes from the introduction of the polymerizable monomer composition, the stirring device was stopped and the composition was transferred to a polymerization tank equipped with a paddle stirring blade. In the polymerization tank, the reaction was carried out at 60 ° C. under N ₂ atmosphere for 10 hours while stirring with a paddle stirring blade. After completion of the polymerization reaction,
The residual monomer was 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 above-mentioned colored suspended particles was measured with a Coulter Multisizer, the weight average diameter was 8.0 μm.
The number of particles having a particle size of m, 4 μm or less was 50% by number, the particle having a particle size of 10.1 μm or more was 15.0% by volume, and the particle size distribution was broader in both the coarse powder side and the fine powder side than in the examples. Hydrophobic silica having a specific surface area of 200 m ² / g by the BET method was externally added to 100 parts by weight of the obtained particles to obtain a suspension polymerization toner 4. 5 parts by weight of this toner was mixed with 95 parts by weight of an acrylic-coated ferrite carrier to prepare a developer. 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, fogging occurred after every 1,000 sheets of durability, and the image quality was also poor. Met.

[0071]

As described above, according to the production method of the present invention, the particle size distribution of the polymerizable monomer composition at the time of granulation can be made sharp, and a classification step is finally required. Moreover, even if the particles are classified, a high-yield toner having a sharp particle size distribution can be obtained.

[0072]

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a specific example of a granulating apparatus used in the manufacturing method of the present invention.

FIG. 2 is an enlarged cross-sectional view of the stirring device in FIG.

FIG. 3 is a schematic sectional view of a specific example of another granulating apparatus used in the manufacturing method of the present invention.

FIG. 4 is a schematic cross-sectional view of a specific example of another granulating apparatus used in the manufacturing method of the present invention.

5 is an enlarged cross-sectional view of the stirring device in FIG.

[Explanation of symbols]

 1: Granulation container 2: Stirring device 3: Stirring shaft 4: Stirring blade 5: Screen 6: Stirring chamber 7: Jacket 8: Stirring device 9: Anchor blade 10: Stirring blade 11: Stator 12: Stirring shaft 13: Stirring chamber

Claims (5)

[Claims] 1. A method for producing a toner, wherein a polymerizable monomer composition is produced by a polymerization method including a toner particle granulation step and a polymerization step, wherein the toner particle granulation step is performed in a granulation container, A step of granulating by dispersing in a liquid dispersion medium that contains a polymerizable monomer composition and a dispersion stabilizer and is substantially incompatible with the polymerizable monomer composition, In the grain container, a stirring device having high shearing force is provided,
The method for producing a toner for developing an electrostatic charge image, wherein the stirring device includes a stirring blade that rotates at high speed and a stirring chamber, and the liquid fluid is configured to jet downward from the stirring chamber. . 2. The method for producing a toner for developing an electrostatic charge image according to claim 1, wherein the axis of the stirring shaft of the stirring device is tiltable with respect to the central axis of the granulation container. 3. The method for producing a toner for developing an electrostatic charge image according to claim 1, wherein the rotating direction of the stirring blade can be rotated in both forward and reverse directions. 4. The method for producing a toner for developing an electrostatic charge image according to claim 1, wherein the toner has a core / shell structure. 5. The main component of the core portion has a melting point of 40 to 90.
The method for producing a toner for developing an electrostatic charge image according to claim 4, which is a substance having a low softening point of ° C.