JPH11352721A - Production of electrostatic charge image developing toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the efficiency of treatment while preventing deterioration in quality due to drying and to realize a safe drying process by measuring the electric field strength and/or potential in a fluidized layer in a drying process and controlling the drying conditions according to the measurement. SOLUTION: An electric field strength meter 14 and/or potentiometer 15 is disposed in a fluidized layer drying machine 1 to measure the electric field strength and/or potential in the fluidized layer. Further, the obtd. measured values are inputted in a personal computer 16 for controlling to control the drying conditions according to the measured values. By measuring the electric field strength and/or potential, the time when the wet toner is excessively dried to decrease its water content which causes a hazard of dust explosion and oxidation of the toner can be indirectly judged. Thereby, at this time, an inert gas is introduced through an inlet 10 and mixed with a fluidizing gas so that the oxygen concn. of the fluidizing gas can be controlled to a degree not to cause dust explosion or oxidation of the toner.

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 image. More specifically, after forming a toner image on an electrostatic latent image carrier in advance, a toner used for a copying machine, a printer, a facsimile, etc., using an electrophotographic method of forming an image by transferring the toner image onto a material to be transferred, is used. The present invention relates to a method for producing a polymerized toner produced using a polymerization method.

[0002]

2. Description of the Related Art Electrophotography is disclosed in U.S. Pat.
A number of methods are known, such as described in the specification of US Pat. No. 691, but generally, an electric latent image is formed on a photoconductor by various means using a photoconductor made of a photoconductive substance. After the latent image is developed using toner to form a visible image, the toner image is transferred to a transfer material such as paper as necessary, and then the image is transferred by heat or pressure. This is to obtain a copy or printed matter by fixing the toner image on the transfer material. Various specific methods have been conventionally proposed as a method of developing using the toner among them or a method of fixing a toner image.

Conventionally, the toner used in the above-described electrophotographic method is usually prepared by melt-kneading a coloring agent composed of a dye or a pigment in a thermoplastic resin, uniformly dispersing these materials, and then finely pulverizing with a pulverizer. After pulverization, the obtained finely pulverized product is classified by a classifier, and is manufactured by a pulverization method for obtaining a toner having a desired particle size. Although the above-described pulverization method for producing a toner can produce a considerably excellent toner, there is a certain limitation, that is, the selection range of the toner material is limited. For example, the toner coarse powder before pulverization must be sufficiently brittle so that it can be easily pulverized by an economically feasible manufacturing apparatus. However, if the toner coarse powder is formed to be brittle to satisfy this requirement, the particle size range of the obtained fine particles tends to be widened when the toner coarse powder is actually finely pulverized at a high speed. This causes fine particles to be contained in the finely pulverized material. Further, there is a problem that a toner obtained from a material having high brittleness as described above is liable to be further pulverized or powdered in a developing device such as a copying machine.

In the method of producing a toner using the above-described pulverizing method, it is difficult to completely and uniformly disperse solid fine particles such as a colorant in a resin. In this case, it may cause an increase in fog, a decrease in image density, poor color mixing or transparency, and the like. Therefore, great care must be taken in dispersing the colorant. In addition, the colorant may be exposed on the fracture surface of the pulverized particles, which may cause fluctuations in the development characteristics.

On the other hand, in order to overcome these problems with the toner formed by the pulverizing method, Japanese Patent Publication No.
JP-A-10231, JP-B-43-10799 and JP-B-51-14895 have proposed various polymerization toners, including suspension polymerization toners, and methods for producing the same. For example, a polymerized toner obtained by using a suspension polymerization method uniformly dissolves a polymerizable monomer, a colorant and a polymerization initiator, and further, if necessary, a crosslinking agent, a charge control agent, and other additives. Or after dispersing into a monomer composition,
The monomer composition was dispersed in a granulated phase containing a dispersion stabilizer, for example, an aqueous phase using a suitable stirrer, and simultaneously subjected to a polymerization reaction and granulated, and then used as a dispersion stabilizer. An acid is added to remove the poorly water-soluble compounds, and these compounds are dissolved.Then, after filtration and washing, the wet colored polymer particles obtained by washing with water are dried to obtain a desired particle size. Obtained as toner particles.

In the method of producing a toner utilizing such a polymerization method, since no pulverizing step is involved, the toner is not required to be brittle as in the case of producing by a pulverizing method, and a soft material is used as a binder resin. Can be used. In addition, since the colorant is not exposed to the particle surface during the pulverizing step, there is an advantage that a toner having uniform triboelectricity can be obtained. Further, since the particle size distribution of the obtained toner particles is relatively sharp, the classification step can be omitted, and in the case of classification, there is an advantage that the toner can be obtained with a high yield. or,
Since a large amount of the low softening point substance that functions as a release agent can be included in the toner, there is also an advantage that the obtained toner has excellent offset resistance.

However, as described above, colored polymer particles obtained by the suspension polymerization method are characterized by the following characteristics:
Since it is produced in an aqueous medium, it needs to be separated from the suspension. In a usual separation method from a suspension, the dispersion stabilizer is removed by a predetermined method, and then sufficiently washed, and then solidified by an appropriate separation means such as filtration, decantation, or centrifugation. Because of the liquid separation, the colored polymer particles are obtained in a wet state. When such polymer particles are used in a toner, it is desirable to minimize the amount of water remaining in these particles from the viewpoint of image performance, and from the viewpoint of environmental health, it is desirable to use a solvent or a solvent in the particles. It is preferable that the residual unreacted monomer is also small. Therefore, the colored polymer particles in the wet state are sufficiently dried to obtain a polymerized toner.

Conventionally, drying of the wet colored polymer particles (hereinafter, also simply referred to as “wet colored polymer particles” or “wet toner”) is performed by a tray dryer, a spray dryer, or a vacuum dryer. And a fluidized-bed dryer.
When the wet colored polymer particles are dried, a relatively low temperature, in order to prevent fixation and aggregation of the colored polymer particles,
For example, it is common to carry out at a powder temperature of 60 ° C. or less. However, if drying is performed using a tray-type dryer or a vacuum dryer at such a temperature, it takes an extremely long time until the water content becomes equal to or less than a predetermined amount of water or the amount of unreacted residual monomer. Further, since a relatively high temperature is required in the spray dryer, in this case, adhesion and fixation of the colored polymer particles easily occur, which is not preferable.

On the other hand, in order to dry efficiently,
Japanese Patent Publication No. 57-779139 proposes a drying method using a fluidized bed dryer. According to this fluidized bed dryer, drying can be performed in a short time, but since the contact ratio with the introduced gas is high, the toner particles are easily oxidized by the introduced gas such as air, and the quality of the obtained toner is deteriorated. Is remarkable. In particular, if the drying is performed sufficiently until the water content becomes less than a predetermined water content and the amount of the unreacted residual monomer, the water content is larger than the amount of the unreacted residual monomer. Is relatively abundantly present on the surface, so that it may selectively evaporate first. Since the moisture also plays a role of covering the toner particle surface and suppressing oxidation, after the moisture is selectively evaporated from the surface of the toner particle, the drying proceeds further to reach a predetermined unreacted monomer amount. In the meantime, a situation occurs where the contact ratio between the surface of the toner particles and the introduced gas increases, and the oxidation of the toner proceeds rapidly. In order to prevent this, it is conceivable to stop the operation of the fluidized bed and terminate the drying in a state where moisture is present on the surface of the toner particles. turn into. Further, in this case, in the drying step, the water content of the toner particles during the operation of the fluidized bed can be continuously measured,
There is a need for a detection method capable of detecting the moment when the moisture content of the drying particles, which is constantly changing, reaches a predetermined moisture content.

Further, in recent years, as the particle size of desired toner particles has become finer, the minimum ignition energy has been reduced,
There is a concern that the generation of static electricity may affect the drying process. In particular, in the case of toner particles having a weight average particle diameter of 10 μm or less, the minimum ignition energy is extremely reduced as compared with particles having a weight average particle diameter exceeding 10 μm. Also, when wet particles having a weight average particle size of 10 μm or less are dried using a fluidized bed dryer, a large amount of static electricity is generated due to friction between the toner particles or friction between the toner particles and the can body of the dryer. Has been confirmed. As a countermeasure to this, grounding is taken reliably, but even if grounding is used, if powder adheres to the inside of the dryer, electric charges will accumulate on the surface of the adhered powder and the suspended dust cloud. I do. And since it is very difficult to remove the electric charge, the electric charge is accumulated sequentially, and if a discharge occurs in which the accumulated energy is released into the fluidized bed, a serious explosion such as dust explosion occurs. There is also a danger of developing into an accident. On the other hand, it is conceivable to change the type of the fluidized gas constituting the fluidized bed to an inert gas or the like which does not cause dust explosion, instead of air which is usually used, but it is not economical. Therefore,
There is a need for a method for economically, efficiently and safely drying toner particles having a small particle diameter.

[0011]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a polymerized toner which solves the above-mentioned problems of the prior art.
In particular, it is an object of the present invention to provide a method for producing a polymerized toner for producing a toner by a polymerization method such as suspension polymerization using an aqueous dispersion. Specifically, an object of the present invention is to provide a toner for developing an electrostatic image by a polymerization method, in a drying step of wet colored polymer particles, to achieve processing efficiency while preventing quality deterioration due to drying, Another object of the present invention is to provide a method of manufacturing a toner for developing an electrostatic image, which can safely perform a drying step. Another object of the present invention is to provide a toner for developing an electrostatic charge image that can minimize the amount of water and the amount of unreacted residual monomer in the toner obtained after drying is completed, and that does not impair the image characteristics of the toner. It is to provide a manufacturing method. Still another object of the present invention is to provide a method for producing a toner for developing an electrostatic image which can efficiently produce a toner for developing an electrostatic image by a suspension polymerization method having good image characteristics.

[0012]

The above object is achieved by the present invention which is described below.
Achieved by Ming. That is, the present invention provides an aqueous dispersion medium
Moisture containing water obtained by the polymerization method using
The fluidized bed is formed by suspending the moist colored polymer particles with a gas.
Producing a polymerized toner having a drying step of drying while forming
A method for producing a toner for developing an electrostatic image, Drying above
In the process, the electric field strength and / or potential in the fluidized bed is measured.
The drying conditions are controlled by this.
This is a method for producing a toner for developing electrostatic images.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail with reference to preferred embodiments. The present inventors have conducted intensive studies to solve the above-mentioned problems of the prior art, and as a result, when drying the wet colored polymer particles obtained by the polymerization method using a fluidized bed drier, If an electric field strength meter and / or an electrometer is installed in the fluidized bed, and the electric field strength and / or the potential is measured, and the drying conditions are controlled based on the measured values, the amount of water and the unreacted The present invention has been found to be able to efficiently and safely obtain an electrostatic image developing toner having excellent image characteristics which can reduce the amount of residual monomer and does not cause deterioration of quality due to oxidation of the toner. Reached. That is, according to the study of the present inventors, if the electric field strength and / or the electric potential of the fluidized bed in the fluidized bed dryer is measured, the moisture content of the wet colored polymer particles during the fluidized bed operation, particularly, on the particle surface, Can be obtained indirectly but continuously,
If the drying conditions are appropriately controlled according to these measured values,
It has been found that the above objective is achieved. Hereinafter, this will be described.

When the wet colored polymer particles are dried using a fluidized bed drier, first, friction occurs between the colored polymer particles or between the colored polymer particles and the main body of the dryer to generate static electricity. However, while the water content of the particles is high, particularly when the water content is 5% or more, a small discharge is generated in the atmosphere at any time due to the moisture contained in these particles, and the electricity is removed. Therefore, in this case, the colored polymer particles themselves are not charged. However, as drying proceeds, the water content of the colored polymer particles decreases. Specifically, when the water content becomes less than 5%, discharge as in the above case does not occur,
The colored polymer particles are rapidly charged. Therefore, if the charged state of the colored polymer particles is measured as an electric field intensity and / or potential by an electric field intensity meter or an electrometer installed in the fluidized bed, the water content of the colored polymer particles in the fluidized bed is indirectly measured. You can know. Furthermore, the point at which the oxidation of the particles is rapidly accelerated is detected by the water content of the colored polymer particles measured indirectly, for example, by reducing the oxygen concentration introduced into the fluidized bed at this point. By doing so, it is possible to efficiently suppress oxidation leading to deterioration of toner quality, and it is possible to efficiently obtain a polymerized toner having excellent image characteristics. At the same time, the danger of an accident such as a dust explosion can be reliably avoided.

The method for producing the toner for developing an electrostatic image of the present invention is directed to a wet colored polymer particle obtained by a polymerization method, in particular, a wet state containing water obtained by a suspension polymerization method using an aqueous dispersion medium. In a method for producing a toner for developing an electrostatic charge image having a drying step of drying a colored polymer particle by floating it with a gas to form a fluidized layer, the electric field strength and / or the electric potential in the fluidized layer are measured. It is characterized in that drying conditions are controlled. Hereinafter, the drying step will be described in detail.

In the method for producing a toner for developing an electrostatic image of the present invention, the wet colored polymer particles introduced into the fluidized bed in the drying step should have a water content as low as possible in order to improve the efficiency of the drying step. Is preferred, but in particular,
From the viewpoint of fluidity, it is preferable to introduce those having a water content of 40% or less. More preferably, the water content is preferably 30% or less. Here, the moisture content refers to the moisture content based on the moisture content, that is, the ratio of the weight of water to the total weight (in this case, the sum of the weight of anhydrous toner and the weight of water). The wet colored polymer particles having a water content of 40% or 30% as described above can be easily obtained from the suspension by ordinary solid-liquid separation means (for example, filtration). The moisture content may be adjusted to, for example, about 30% before the drying and introduction into the dryer. The configuration of the fluidized bed dryer that can be suitably used in the present invention will be described later.

Conventionally, various methods have been proposed as a method for drying wet toner particles. However, according to fluidized bed drying in which toner particles are dried while floating in an air stream and fluidized. It has been confirmed that drying can be performed efficiently in a short time, but in this case, toner particles may adhere in the fluidized bed dryer. Here, it has been found that in order to obtain a higher quality image, it is effective to make toner particles finer. However, in this case, the adhesion of the toner in the fluidized bed dryer becomes more remarkable. In particular, the weight average particle diameter of the toner particles is 10 μm.
When it is less than m, the tendency becomes more remarkable. As a countermeasure against this, a method of forcibly removing the toner adhering to the inside of the dryer, for example, a method of mechanically scraping off or blowing off with air can be considered. However, this can temporarily remove the adhered toner,
Since the powder particles are constantly flowing, toner adhesion and forced peeling are repeated. In such a state, frictional charging occurs between the toner particles or between the toner particles and the main body of the dryer. According to the measurement by the present inventors, even when the dryer body is securely grounded, for example, the electric field strength in the fluidized bed is 5 kV / cm or more, and the potential is 5 kV near the inner wall surface of the fluidized bed dryer. Some cases have been observed. If the dryer is operated in such a state, there is a risk that a serious accident such as a dust explosion may occur when a discharge occurs in which the energy accumulated by the charging is released into the fluidized bed. The present inventors have found that it is important to manage the oxygen concentration of the flowing gas constituting the fluidized bed in the dryer in an optimal state in order to solve this problem and reliably prevent the occurrence of an accident. Was.

According to the study of the present inventors, particularly when the electric field strength and the potential in the fluidized bed show high values, the oxygen concentration of the flowing gas in the dryer is preferably reduced to 12%.
% Or less, more preferably 8% or less, it was found that the toner can be dried stably and safely. That is, as described above, as the drying state of the toner particles progresses, the particles easily become charged due to friction, and the above-described accident may occur. Therefore, the electric field strength and potential in the fluidized bed are measured, whereby the dry state (water content) of the toner particles during the drying process is indirectly known, and the composition of the fluidized gas constituting the fluidized bed according to the dry state is determined. Even if a discharge occurs in which the energy stored by charging is released into the fluidized bed, a dust explosion occurs because the oxygen concentration of the gas constituting the fluidized bed is reduced. It does not cause the risk of accident occurrence.

The present inventors have studied various means for reducing the oxygen concentration of the flowing gas in the dryer as described above. As a result, it is effective to use an inert gas as the main component of the introduced gas. It turned out to be. Examples of the inert gas include helium, argon, and nitrogen gas. In particular, the use of nitrogen gas is effective from the viewpoint of cost, and furthermore, the inert gas is effectively used. To this end, it has been found useful to use the gas constituting the fluidized bed in a circulating manner. With this configuration, the inert gas used for reducing the oxygen concentration of the flowing gas such as air constituting the fluidized bed can be efficiently used, so that the cost of the introduced gas can be reduced to a minimum.

Hereinafter, a method for drying the wet colored polymer particles (wet toner) in the method for producing a toner for developing an electrostatic image of the present invention will be specifically described. First, for example, the electric field strength and / or the electric potential in the fluidized bed when the water content of the toner particles is 5% are measured in advance. Then, when the wet toner particles are dried using a fluidized bed dryer, the electric field strength and / or the potential in the fluidized bed are continuously measured, and the measured value indicates that the water content of the toner particles obtained above is When the electric field strength and / or the electric potential becomes higher than 5%, an inert gas such as nitrogen gas is introduced to reduce the oxygen concentration of the flowing gas to, for example, 12% or less. Constitute. That is, according to the above configuration, the moisture content of the toner particles in the fluidized bed during drying can be indirectly known from the electric field strength and / or the potential value in the fluidized bed. At the time when the water content at which charging progresses rapidly reaches 5%, the oxygen concentration of the gas constituting the fluidized bed can be reduced to 12% or less. As a result, even if a discharge occurs in the fluidized bed, there is no danger of dust explosion. Furthermore,
When drying progresses and the water content of the toner particles decreases,
Although the water covering the toner particle surface is selectively evaporated and the toner particles are easily oxidized, in the present invention, since the oxygen concentration of the gas constituting the fluidized bed is reduced in this case, Oxidation of the toner is effectively suppressed. As a result, quality deterioration due to oxidation of the toner particles, which has conventionally occurred in the drying step, is effectively suppressed.

In the method for producing a toner for developing an electrostatic image of the present invention, as described above, the danger of dust explosion is reliably avoided in the step of drying the wet toner particles.
It is suitable for producing a toner which easily generates a dust explosion having a minimum ignition energy of 50 mJ or less, and further has a minimum ignition energy of 30 mJ or less, more preferably 10 mJ or less.
This is a more effective means in the case of mJ or less. That is, the smaller the minimum ignition energy of the toner particles, the easier it is to cause a dust explosion, but using the toner manufacturing method of the present invention,
As described above, in the drying step, the fluidized bed is reliably prevented from being in a state in which dust explosion is likely to occur, so that dust explosion does not occur. Further, since the minimum ignition energy of the toner particles becomes smaller as the particle size of the toner particles becomes smaller, the method for producing a toner for developing an electrostatic image of the present invention has a weight average particle diameter of 10 μm or less, and further 8 μm. This is particularly effective when producing the following toner.

Next, a specific drying apparatus flow used in the drying step of the method for producing a toner for developing an electrostatic image of the present invention will be described in detail. FIG. 1 shows an example of an apparatus flow for carrying out the toner manufacturing method of the present invention.
In FIG. 1, 1 is a fluidized bed dryer body, 2 is a bag filter, 3 is a raw material inlet, 4 is a powder outlet, 5 is a blow blower, 7 is a condenser, 8 is a heat exchanger, and 9 is an inlet. Air damper, 10 is an inert gas inlet, 11 is an exhaust damper, 1
2 is an eye plate, 13 is an inlet, 14 is an electric field strength meter, 15 is an electrometer, 16 is a personal computer used for controlling drying conditions,
17 is an oxygen concentration meter.

In the present invention, as shown in this flow chart (FIG. 1), it is preferable to circulate and use the gas constituting the fluidized bed as a closed system. First, the flow of the airflow will be described with reference to FIG. The gas such as air taken in from the inlet 13 is adjusted to a predetermined temperature by a heat source such as steam in the heat exchanger 8. The temperature-controlled gas flows into the fluidized-bed dryer main body at a flow rate from the opening of the perforated plate 12 of the fluidized-bed dryer main body 1 through the blowing blower 5, and is injected through the inlet 3. The wet colored polymer particles (raw materials) are loaded and fluidized. At this time, moisture and the like from the wet raw material evaporate efficiently in the temperature-controlled air stream, and the raw material is dried. The gas moistened by the contact with the wet raw material passes through the bag filter 2 to remove particles, and is exhausted from the dryer main body 1 by opening the exhaust damper 11. The exhausted gas is sent to a condenser 7 via an exhaust blower 6, and after the moisture, solvent and unreacted monomer components are removed by the condenser 7, the gas is sent to a heat exchanger 8, It is recycled again.

In the present invention, as shown in FIG. 1, an electric field strength meter 14 and / or an electrometer 15 are disposed in the fluidized bed dryer having the above-described structure, so that the electric field strength in the fluidized bed can be reduced. And / or the potential can be measured, and the obtained measured value is input to the control personal computer 16 so that the drying conditions can be controlled in accordance with the measured value. In the dryer shown in FIG. 1, when the measured value of the electric field strength and / or the potential in the fluidized bed becomes a specific value, the inert gas is contained in the temperature-controlled gas exiting the heat exchanger 8. The gas is introduced so as to have an appropriate concentration, and is configured so that the oxygen concentration of the gas constituting the fluidized bed can be reduced. That is, with the above configuration, by measuring the electric field strength and / or potential in the fluidized bed, drying proceeds, the water content of the wet toner decreases, and the risk of dust explosion and oxidation of the toner occur. Since it is possible to indirectly know when the fear has come out, at that time, an inert gas is introduced from the inlet 10 and mixed into the flowing gas, so that the oxygen concentration of the flowing gas can be reduced by a dust explosion or a toner explosion. It can be controlled to the extent that oxidation does not occur. In the dryer shown in FIG. 1, whether or not the oxygen concentration of the flowing gas has reached a desired value due to the incorporation of the inert gas is checked by the oximeter 17. The value is also input to the personal computer so that the inert gas is surely introduced until the flowing gas reaches a preset oxygen concentration. As a result, the oxygen concentration of the flowing gas can be easily and accurately changed according to the dry state of the wet toner, so that safe and economical drying without deterioration of toner quality is realized. .

As mentioned above, it is very important to accurately control the oxygen concentration in the flowing gas into which the wet particles to be dried are introduced. Therefore, it is preferable that the oxygen concentration meter 17 is installed in the circulation line, and that the installation site is located just before the blow blower 5 immediately before the gas is introduced into the dryer 1. In this way, the oxygen concentration in the flowing gas can be controlled accurately. That is, the measured values of the electric field intensity and / or the electric potential measured by the electric field intensity meter 14 and / or the electrometer 15 in which the measuring terminal is installed in the fluidized bed dryer are input to the personal computer 16, while the inside of the dryer 1 is Since the oxygen concentration of the gas introduced into the air is measured by the oximeter 17 and the measured value is also input to the personal computer 16,
The time when the oxygen concentration is reduced is detected in accordance with the measured value of the electric field strength. At that time, the mixing of the inert gas is started from the gas inlet 10 and the value of the oxygen concentration in the gas measured by the oxygen concentration meter 17 If the inert gas is controlled to be continuously introduced from the gas inlet 10 until the gas concentration becomes 12% or less, preferably 8% or less, a gas having a desired oxygen concentration can be reliably introduced into the dryer.

Further, in the drying step, the control of the flow velocity of the fluidized bed in the fluidized bed dryer is determined by the balance between the gas blowing amount and the gas discharging amount. This is performed by controlling the degree of opening and closing of the damper 11. The fluidized state of the wet-colored polymer particles introduced into the fluidized-bed dryer depends on the properties (specific gravity, specific gravity,
(The amount of water, particle diameter, etc.), it is preferable to appropriately select the drying conditions according to the properties of these raw material powders. For example, the temperature at which the gas is blown into the fluidized-bed dryer 1 is preferably 70 ° C. or lower, more preferably 60 ° C. or lower. That is, if the temperature of the gas blown into the fluidized bed dryer is too high, the aggregation and deformation of the particles,
It is not preferable because fusion occurs.

The powder raw material that has been dried as described above is discharged from the discharge port 4 to the outside of the system. As described above, in the present invention, it is preferable to perform the drying step in a closed system, but in actual operation, it is difficult to operate in a completely closed state. Therefore, when the operation is performed in a state where the oxygen concentration is reduced, the operation is performed while appropriately replenishing a necessary amount of the inert gas. If necessary, a part of the gas is discharged from the outlet of the exhaust blower 6. Operate while discharging. Further, in the condenser 7, it is necessary to sufficiently coagulate and remove water and unreacted residual monomers contained in the gas. For this purpose, it is preferable to provide the aggregator 7 with a sufficient cooling function so that the temperature of the gas in the aggregator 7 can be controlled to 30 ° C. or less.

In the present invention, the fluidized bed dryer preferably used is not limited to the configuration shown in FIG. 1, and a general apparatus for drying the powder particles in a fluidized state may be used. Can also. As described above, in the present invention, since it is possible to dry at a low oxygen concentration by using an inert gas as needed, even if the surface charge of the powder during drying is increased, Since it can be dried at the oxygen concentration below the lower limit of explosion, there is no danger of dust explosion and it can be operated safely. Furthermore, since the drying can be performed with the probability of oxygen being suppressed, even if the toner particles are easily oxidized, the oxidation of the toner particle surface can be effectively prevented, and the charging stability and environmental resistance stability can be improved. A toner having excellent properties such as properties is obtained. In particular, a toner having excellent charge stability under high temperature and high humidity can be obtained.

In the method for producing a polymerized toner of the present invention,
The wet colored polymer particles subjected to the drying step performed using the dryer as described above, a polymerizable monomer composition containing at least a polymerizable monomer and a colorant, a poorly water-soluble compound It is obtained by polymerizing in a contained aqueous dispersion. As the polymerizable monomer used at this time, for example, styrene, o (m-, p-)-methylstyrene, m
Styrene 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, behenyl (meth) acrylate, 2-ethylhexyl (meth) acrylate (Meth) acrylate monomers such as dimethylaminoethyl (meth) acrylate and diethylaminoethyl (meth) acrylate; ene monomers such as butadiene, isoprene, cyclohexene, (meth) acrylonitrile and acrylamide Body.

The polymerizable monomers as described above are used alone,
Or, in general, the publication Polymer Handbook No. 2
Edition III-P139-192 (John Wiley & S
ons Co., Ltd.) has a theoretical glass transition temperature (Tg) of 4
The monomers are appropriately selected from the above monomers so as to show a temperature of 0 to 80 ° C, and used by mixing. That is, when a polymerizable monomer having a theoretical glass transition temperature of less than 40 ° C. is used, the resulting polymerized toner may cause problems in terms of storage stability and durability stability of the developer. is there. On the other hand, when a polymerizable monomer having a theoretical glass transition temperature (Tg) of more than 80 ° C. is used, the fixing point is increased. In particular, in the case of a full-color toner, the suppression of color mixing of each color toner is insufficient. As a result, the color reproducibility is poor, and the transparency of the OHP image is remarkably reduced. Therefore, it is not preferable from the viewpoint of obtaining a toner having excellent characteristics capable of forming a high quality image.

In the present invention, the molecular weight of the binder resin constituting the polymerized toner is measured by GPC (gel permeation chromatography). As a specific GPC measurement method, a polymerized toner was previously extracted with a toluene solvent using a Soxhlet extractor for 20 hours, and then toluene was distilled off with a rotary evaporator.
(Tetrahydrofuran). This THF solution is filtered through a solvent-resistant membrane filter having a pore diameter of 0.3 μm to prepare a measurement sample. The measuring apparatus used was 150C manufactured by Waters, and the column configuration was A-801, 802, 803, 804, 80 manufactured by Showa Denko KK
What connected 5,806,807 was used. to this,
About 100 ml of the sample obtained above is injected and measured. In measuring the molecular weight distribution of the sample, the molecular weight distribution of the sample was calculated from the relationship with the calibration curve created from the standard polystyrene resin sample. In the present invention, the number average molecular weight (Mn) obtained as described above is 5,000.
It is preferable to use a binder resin having a weight average molecular weight (Mw) and a number average molecular weight (Mn) in a range of 2 to 100 (Mw / Mn).

When the polymerized toner has a core / shell structure, the main component of the core is preferably a substance having a low softening point, and the main component maximum peak value measured according to ASTM D3418-8 is preferably used. , 40-90 ° C. If the maximum peak is less than 40 ° C., the self-cohesive force of the low softening point substance becomes weak, and as a result, the hot offset resistance becomes weak, which is not preferable. On the other hand, if the maximum peak exceeds 90 ° C., the fixing temperature increases, which is not preferable. Further, if the temperature of the maximum peak value is high, a substance having a low softening point is deposited mainly during granulation, which hinders the suspension system, which is not preferable. For the measurement of the temperature of the maximum peak value in the present invention, for example, DSC-7 manufactured by Perkin Elmer Co., Ltd. is used. The temperature correction of the device detection unit uses the melting points of indium and zinc, and the heat quantity correction uses the heat of fusion of indium. An aluminum pan was used as a sample, an empty pan was set as a control, and the measurement was performed at a heating rate of 10 ° C./min.

As the low softening point substance used in the present invention, specifically, for example, paraffin wax, polyolefin wax, Fischer-Tropsch wax,
Examples include amide waxes, higher fatty acids, ester waxes, derivatives thereof, and graft / block compounds thereof. Also, the low softening point substance is added to the toner in an amount of 5 to 3%.
It is preferable to add 0% by weight. If the addition is less than 5% by weight, it takes a burden to remove the residual monomers described above. If the addition exceeds 30% by weight, coalescence of the toner particles occurs during granulation even in the production by the polymerization method. It was easy to produce a product having a wide particle size distribution, and was not suitable for the present invention.

As a specific method for encapsulating a low softening point substance, for example, the polarity of the material in an aqueous medium is set to be smaller for the low softening point substance than for the main monomer, and a small amount of By adding a resin or monomer having high polarity, 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. Control of the particle size distribution and particle size of the toner are carried out by changing the type and amount of the hardly water-soluble inorganic salt or dispersant that acts as a protective colloid and mechanical device conditions, for example, the peripheral speed of the rotor, the number of passes, By controlling the stirring conditions such as the shape of the stirring blade, the shape of the container, or the solid content concentration in the aqueous solution, toner particles having a predetermined particle size distribution and particle size can be obtained.

In the present invention, in order to confirm whether the toner particles have a core / shell structure, a method for measuring the tomographic plane of the toner particles includes dispersing the toner particles in an epoxy resin curable at room temperature. After curing, the cured product was cured in an atmosphere at a temperature of 40 ° C. for 2 days, and the obtained cured product was dyed using ruthenium tetroxide and, if necessary, osmium tetroxide in combination. A flaky sample was cut out using the above method, and the tomographic morphology of the toner was measured using a transmission electron microscope (TEM). In the present invention, it is preferable to use a ruthenium tetroxide staining method in order to give a contrast between materials by utilizing a slight difference in crystallinity between the low softening point substance used and the binder resin constituting the outer shell. .

In the present invention, when a toner having a core / shell structure is produced, a polar resin is further added in addition to the outer shell resin in order to include a low softening point substance in the outer shell resin. Is particularly preferred. Examples of the polar resin used in the present invention include a copolymer of styrene and (meth) acrylic acid, a maleic acid copolymer, a saturated polyester resin, and an epoxy resin. The polar resin used in the present invention is particularly preferably one containing no unsaturated group capable of reacting with the outer shell resin or monomer in the molecule. When a polar resin having an unsaturated group is included, a cross-linking reaction occurs between the monomer and the monomer forming the outer shell resin. It is disadvantageous and not preferred.

In the present invention, the surface of the toner is
Further, an outermost shell resin layer may be provided. The glass transition temperature of the outermost resin layer is designed to be equal to or higher than the glass transition temperature of the outer resin layer for further improvement of blocking resistance.
Further, it is preferable that the crosslinking is carried out so as not to impair the fixability. It is preferable that the outermost resin layer contains a polar resin and a charge control agent for improving the chargeability.

The method for providing the outermost shell resin layer is not particularly limited, and examples thereof include the following method. (1) In the second half or after the end of the polymerization reaction, if necessary, a monomer in which a polar resin, a charge control agent, a cross-linking agent, and the like are dissolved and dispersed is added to the reaction system, and the resultant is adsorbed on the polymerized toner particles, and the polymerization initiator is added. A method in which polymerization is performed by addition. (2) If necessary, emulsion polymerization particles or soap-free polymerization particles comprising a monomer containing a polar resin, a charge control agent, a cross-linking agent, etc., are added to the reaction system and aggregated on the surface of the polymerization toner particles, if necessary. By heat or the like. (3) A method in which emulsion polymerized particles or soap-free polymerized particles comprising a monomer containing a polar resin, a charge control agent, a cross-linking agent, and the like are dry-mechanically fixed to the toner particle surface as required.

The coloring agents used in the present invention include the following. Examples of the black colorant include carbon black, a magnetic substance, and a colorant adjusted to black using a yellow / magenta / cyan colorant shown below. As a yellow colorant, for example, a condensed azo compound, an isoindolinone compound, an anthraquinone compound,
Examples include compounds represented by azo metal complexes, methine compounds, and allylamide compounds. Specifically, for example,
C. I. Pigment Yellow 12, 13, 14, 15,
17, 62, 74, 83, 93, 94, 95, 109,
110, 111, 128, 129, 147, 168 and the like.

Examples of the magenta colorant include condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds and perylene compounds. In particular,
For example, C.I. I. Pigment Red 2, 3, 5, 6,
7, 23, 48: 2, 48: 3, 48: 4, 57: 1,
81: 1, 144, 146, 166, 169, 177,
184, 185, 202, 206, 220, 221, 2
54 and the like.

Examples of the cyan colorant include copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds, and basic dye lake compounds. Specifically, for example, C.I. I. Pigment Blue 1, 7, 15,
15: 1, 15: 2, 15: 3, 15: 4, 60, 6
2, 66 and the like. These colorants can be used alone or as a mixture, or in the form of a solid solution.

When the colorant as described above used in the present invention is used for producing a color toner, the hue angle, saturation,
It is appropriately selected and used in view of lightness, weather resistance, OHP transparency, and dispersibility in toner. The colorant may be added in an amount of about 1 to 20 parts by weight based on 100 parts by weight of the binder resin. When a magnetic material is used as the black colorant, it is preferable to add 40 to 150 parts by weight to 100 parts by weight of the resin, unlike the case of other colorants.

As the charge control agent that can be used in the present invention, conventionally known charge control agents can be used. In the case of a color toner, in particular, the toner is colorless and the charge speed of the toner is increased. It is preferable to use a charge control agent capable of stably maintaining a constant charge amount. Further, it is particularly preferable to use a charge control agent which does not inhibit polymerization and does not generate a solubilized substance in an aqueous medium.
Specific compounds having the above-mentioned properties include:
For example, negative charge control agents include salicylic acid, naphthoic acid, a metal compound of dicarboxylic acid, sulfonic acid,
Examples thereof include a high molecular compound having a carboxylic acid in a side chain, a boron compound, a urea compound, a silicon compound, and carricks arene. Examples of the positive charge control agent include a quaternary ammonium salt, a polymer compound having the quaternary ammonium salt in a side chain, a guanidine compound, an imidazole compound, and the like.

The amount of the charge control agent as described above is preferably in the range of 0.5 to 10 parts by weight based on 100 parts by weight of the binder resin. However, in the method for producing a polymerized toner of the present invention, the addition of a charge control agent as described above is not essential. This is because, when the polymerized toner obtained by the present invention is used in the two-component developing method, the toner is charged by utilizing frictional charging with the carrier, and when the polymerized toner is used in the non-magnetic one-component blade coating developing method. Does not necessarily include a charge control agent in the toner because the toner is positively charged by frictionally charging the toner with the blade member or the sleeve member.

In the method for producing a polymerized toner of the present invention, the polymerizable monomer composition is polymerized in an aqueous dispersion containing a poorly water-soluble compound to produce colored polymer particles (granulation). At the time of granulation, the following polymerization initiators can be used. 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-dimethylvalero Azo or diazo polymerization initiators such as nitrile and azobisisobutyronitrile;
It is preferable to use a peroxide polymerization initiator such as benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, 2,4-dichlorobenzoyl peroxide and lauroyl peroxide. The amount of the polymerization initiator to be added varies depending on the desired degree of polymerization, but is generally 0.5 to 20% by weight based on the polymerizable monomer.
It is used after being added to some extent. Although the kind of the polymerization initiator also slightly varies depending on the polymerization method, it is used alone or in combination with reference to the 10-hour half-life temperature. In the present invention, in order to control the degree of polymerization, a conventionally known crosslinking agent, chain transfer agent, polymerization inhibitor and the like can be further added and used.

In the present invention, the polymerizable monomer composition constituted as described above is polymerized in an aqueous dispersion containing a poorly water-soluble compound to form colored polymer particles (polymerized toner). (Granulation). In the present invention, examples of the poorly water-soluble compound used as a dispersant at the time of polymerization include the following. For example, inorganic poorly water-soluble compounds include tricalcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, calcium carbonate, magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, and calcium metasilicate. , Calcium sulfate, barium sulfate, bentonite, silica, alumina, magnetic material, ferrite and the like. Examples of the poorly water-soluble organic compound include polyvinyl alcohol, gelatin, methyl cellulose, methyl hydroxypropyl cellulose, ethyl cellulose, sodium salt of carboxymethyl cellulose, starch and the like. In the present invention, these poorly water-soluble compounds are used after being dispersed or partially dissolved in an aqueous medium. The amount of the hardly water-soluble compound used as a dispersant is 0.2 to 100 parts by weight of the polymerizable monomer.
It is preferred to use 10.0 parts by weight.

As these dispersants, commercially available ones may be used as they are. However, in order to obtain finely dispersed particles having a uniform particle size, a poorly water-soluble compound is produced under high-speed stirring in an aqueous dispersion. It is preferable to use them. For example, when using tricalcium phosphate as a poorly water-soluble compound, a preferable dispersant that can be used in the polymerization method is obtained by mixing an aqueous sodium phosphate solution and an aqueous calcium chloride solution under high-speed stirring. Can be. In order to further refine these dispersants, polymerizable monomers 1
A surfactant of about 0.001 to 0.1 part by weight may be used in combination with 00 parts by weight. As the surfactant used at this time, various commercially available nonionic, anionic and cationic surfactants can be used. Specifically, for example, sodium dodecyl sulfate,
Examples include sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium laurate, potassium stearate, calcium oleate, and the like.

That is, a releasing agent, a colorant, a charge control agent, a polymerization initiator and other additives comprising a low softening point substance are added to the polymerizable monomer, and the mixture is uniformly mixed with a homogenizer, an ultrasonic disperser or the like. The dissolved or dispersed monomer system is dispersed in an aqueous phase containing a poorly water-soluble compound by a homomixer or the like while monitoring the particle size with an inline particle size distribution analyzer. The granulation of the droplets of the monomer composition is stopped when the desired toner particle size is obtained. Thereafter, stirring may be performed to such an extent that the state of particles is maintained and sedimentation of particles is prevented by the action of the poorly water-soluble compound. or,
The polymerization is preferably performed at a polymerization temperature of 40 ° C or higher, generally 50 to 90 ° C. Further, the temperature may be raised in the latter half of the polymerization reaction, and further, in order to remove unreacted polymerizable monomers and by-products, in the latter half of the reaction or after completion of the reaction, a part of the aqueous medium is distilled off. Is also good. After completion of the reaction, the produced colored polymer particles are collected by washing and filtration. 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.

In the method for producing a polymerized toner of the present invention,
After the wet colored polymer particles are dried to obtain toner particles, it is preferable that inorganic fine powder or the like is added and mixed into the toner as needed. As the external additive to be added and mixed at this time, it is preferable to use an external additive having a particle diameter of 1/10 or less of the weight average particle diameter of the toner particles from the viewpoint of durability when added to the toner. The particle size of the additive means an average particle size determined by observing the surface of the toner particles with an electron microscope. Examples of the external additives that can be used in the present invention include the following.

Specifically, for example, metal oxides (such as aluminum oxide, titanium oxide, strontium titanate, cerium oxide, magnesium oxide, chromium oxide, tin oxide and zinc oxide), nitrides (such as silicon nitride), and 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 and the like. These external additives are used in an amount of 0.01 to 10 parts by weight, preferably about 0.05 to 5 parts by weight, based on 100 parts by weight of the toner particles. These external additives may be used alone or in combination.
Further, it is more preferable that each of these external additives is subjected to a hydrophobic treatment.

The particle size distribution of the toner can be measured by various methods. In the present invention, the number distribution and the volume distribution are measured by the following methods using the following measuring apparatus. That is, as a measuring device, Coulter counter T
A-II type or Coulter Multisizer II (manufactured by Coulter) connected to an interface (manufactured by Nikkaki) for outputting the number distribution and volume distribution and a PC9801 personal computer (manufactured by NEC) Used. As an electrolytic solution, an approximately 1% NaCl aqueous solution is prepared using primary sodium chloride and used. As the electrolytic solution, for example, ISOTON-II (manufactured by Coulter Scientific Japan) can be used. As a measuring method, first, the electrolytic solution aqueous solution 100
0.1 to 5 ml of a surfactant, preferably an alkylbenzenesulfonate, is added as a dispersant in ~ 150 ml;
After adding 2 to 20 mg of the measurement sample therein, the electrolyte in which the sample is suspended is subjected to a dispersion treatment for about 1 to 3 minutes by an ultrasonic disperser to prepare a measurement sample. Next, a volume distribution and a number distribution were calculated by measuring the volume and the number of the toner by using the measuring apparatus described above and using a 100 μm aperture as the aperture. Further, a weight-average weight-average particle diameter (the median value of each channel is set as a representative value for each channel) was determined from the volume distribution.

In the present invention, the image density is (5 mm square,
Macbeth densitometer (made by Macbeth)
Was measured.

The electric field strength in the present invention is a value indicating the strength of the potential gradient existing in the fluidized bed. In the present invention,
The electric field strength is measured by an electric field detection system, Static Eye (model KSV800A) manufactured by Kasuga Electric Co., Ltd. as an electric field strength meter.
P). The electric potential was measured using ES-BOY of Nippon Kayaku Co., Ltd. as an electrometer.

[0054]

EXAMPLES The present invention will be described more specifically with reference to examples and comparative examples below, but the present invention is not limited to only these examples. In Examples and Comparative Examples, “%” means “% by weight” unless otherwise specified.

Example 1 First, deionized water 1,14
To 0 g, 7,200 g of a 0.1 M Na ₃ PO ₄ aqueous solution was added, and the solution was heated to 60 ° C., and then stirred at 9,000 rpm using a TK homomixer (manufactured by Tokushu Kika Kogyo). did. And in this high-speed stirred solution,
1,090 g of a 1.0 M CaCl ₂ aqueous solution was gradually added to obtain an aqueous dispersion in which Ca ₃ (PO ₄ ) ₂ , a poorly water-soluble compound, was uniformly dispersed.

On the other hand, the following formulation was heated to 60 ° C., and 9000 r using a TK homomixer (manufactured by Tokushu Kika Kogyo).
By stirring at pm, these components were uniformly dissolved and dispersed. Further, 150 g of a polymerization initiator 2,2′-azobis (2,4-dimethylvaleronitrile) was added to and dissolved in this solution to prepare a polymerizable monomer composition. (Monomer) Styrene 2,640 g n-butyl acrylate 560 g (colorant) I. Pigment Blue 15: 3 250 g (charge control agent) salicylic acid metal compound 40 g (polar resin) saturated polyester (acid value 10, peak molecular weight: 7,500) 150 g (mold release agent) ester wax (melting point 70 ° C.) 500 g

Next, the above-mentioned polymerizable monomer composition was put into the previously prepared aqueous dispersion containing the poorly water-soluble compound, and the mixture was subjected to TK homomixer at 60 ° C. under N ₂ atmosphere. The polymerizable monomer composition was polymerized and granulated while stirring at 9,000 rpm. Thereafter, the mixture was heated to 80 ° C. while stirring with a paddle stirring blade, and reacted for 10 hours. After the completion of the polymerization reaction, the remaining monomer was distilled off under reduced pressure. After cooling, hydrochloric acid was added to the reaction vessel to dissolve the calcium phosphate, followed by filtration, washing and dehydration to obtain wet colored particles A. The moisture content of the obtained wet colored particles A is 30%, and
The residual unreacted styrene monomer content is 50
It was 0 ppm.

Next, the wet colored particles A obtained above
Was put into the fluidized bed dryer 1 in which the electric field strength meter 14 of the type shown in FIG. 1 was installed, and was dried. The components of the introduced gas were 95% nitrogen gas and 5% oxygen, and the drying temperature was 80 ° C. The introduced gas is exhausted from the exhaust port 11 and exhaust gas blower 6
And cooled to 20 ° C. in the condenser 7 to condense and remove water and unreacted monomers. Thereafter, the gas from which water and the like had been removed was heated to 50 ° C. through the heat exchanger 8 through the circulation line, and was introduced again into the fluidized-bed dryer 1 through the intake blower 6.

The electric field intensity is 1 k until one hour after the start of drying.
V / cm. After 1 hour, the powder in the fluidized bed was taken out, and the water content and the styrene content were measured. As a result, the water content was 5.3% and the styrene content was 490 ppm.
The water content was measured by Karl Fischer titration,
The amount of styrene was measured by gas chromatography. The electric field intensity started to increase gradually from one hour after the start of drying, and showed 3 kV / cm two hours later. The powder in the fluidized bed after 2 hours was taken out, and the water content and the styrene content were measured. The water content was 1.2%,
The styrene content was 300 ppm. Furthermore, when the drying was continued as it was, after 3 hours, the electric field intensity was 5 kV /
cm. Take out the powder in the fluidized bed after 3 hours,
When the water content and the styrene content were measured, the water content was 0.1% and the styrene content was 20 ppm. Thus, it was confirmed that the electric field intensity and the water content were correlated (see Table 1 and FIG. 2).

The particle size distribution of the dry toner obtained above was measured with a Coulter counter, and it was found that the weight average particle size was 6.5 μm and the coefficient of variation was 30%. When the minimum ignition energy of the dried toner was measured by a Hartmann explosion tester, it was 1 mJ, and it was confirmed that the powder was very easily ignited.

Next, 5 parts of hydrophobic silica having a specific surface area of 200 m ² / g by the BET method is externally added to 100 parts by weight of the dry toner, and the dry toner of the present embodiment containing the dry toner is added. Polymerized toner 1 was obtained. Further, 95 parts by weight of an acryl-coated ferrite carrier was mixed with 5 parts by weight of the toner to obtain a two-component developer. Next, using this developer, a Canon full-color copying machine CLC5
When a continuous remodeling machine was used to evaluate 5,000 continuous images, no fog was found, the image density was stable, and good images were obtained. In addition, the charge stability was excellent, and the charge amount was not reduced even in a high temperature and high humidity environment, and a stable and good image was obtained.

Example 2 The same colored polymer particles A as used in Example 1 were applied to a field intensity meter 14 of the type shown in FIG.
Was discharged into the fluidized-bed dryer 1 in which the exhaust gas was discharged from the exhaust blower 6 to the atmosphere without circulation. As the fluidized gas, air (oxygen concentration: 21%) was allowed to flow in naturally from the inlet 13 and used, and the temperature of the gas introduced into the fluidized-bed dryer 1 was set to 50 ° C. As a result, the electric field intensity was 1 kV / cm until one hour after the start of drying. One hour later, the powder in the fluidized bed was taken out, and the water content and the styrene content were measured. The water content was 5.1% and the styrene content was 4%.
It was 70 ppm. As in Example 1, the water content was measured by Karl Fischer titration, and the styrene content was measured by gas chromatography.

Since the electric field strength gradually started from one hour after the start of drying, after 15 minutes, the introduced gas was switched to a gas of 93% nitrogen gas and 7% oxygen, and the introduced gas was blown. The drying was continued at 50 ° C. in the same manner. 2 hours after the start of drying, the electric field intensity was 3.2 kV / cm.
showed that. The powder in the fluidized bed after 2 hours was taken out, and the water content and the styrene content were measured.
3%, styrene content was 280 ppm. When drying was continued as it was, after 3 hours, the electric field intensity was 5.1 k.
V / cm. The powder in the fluidized bed after 3 hours was taken out, and the water content and the styrene content were measured. As a result, the water content was 0.12% and the styrene content was 25 ppm. Thus, it was confirmed that the measured value of the electric field intensity and the water content were correlated (see Table 1 and FIG. 2). When the particle size distribution of the obtained dry toner was measured by a Coulter counter, the weight average particle size was 6.5 μm, and the coefficient of variation was 30%. When the minimum ignition energy of the dried toner was measured by a Hartmann explosion tester, it was 1 mJ, and it was confirmed that the powder was very easily ignited.

Next, 5 parts of 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 above-mentioned dry toner, and this embodiment containing the above-mentioned dry toner was added. Of Polymerized Toner 2 was obtained. Further, the toner 5
A two-component developer was prepared by mixing 95 parts by weight of an acrylic-coated ferrite carrier with respect to parts by weight. Next, using this developer, a full-color copier CLC manufactured by Canon
Evaluation of image output on 5,000 continuous sheets was performed using a 500-model remodeling machine. As a result, there was no fog, the image density was stable, and a good image was obtained. In addition, the charge stability was excellent, and the charge amount was not reduced even in a high temperature and high humidity environment, and a stable and good image was obtained.

Example 3 The same colored polymer particles A as used in Example 1 were put into a fluidized bed dryer 1 equipped with an electrometer 15 of the type shown in FIG. 1 and dried. Drying conditions were the same as in Example 1. One hour after the start of drying, the potential was less than 1 kV. After 1 hour, the powder in the fluidized bed was taken out, and the water content and the styrene content were measured. The water content was 5.4% and the styrene content was 490 ppm.
Met. The water content was measured by Karl Fischer titration, and the styrene content was measured by gas chromatography.

From one hour after the start of drying, the potential gradually started to increase and showed 3 kV two hours later.
After 2 hours, the powder in the fluidized bed was taken out, and the water content and the styrene content were measured. As a result, the water content was 1.2% and the styrene content was 310 ppm. When the drying was continued as it was, the potential reached 7 kV after 3 hours. The powder in the fluidized bed after 3 hours was taken out, and the water content and the styrene content were measured. As a result, the water content was 0.1% and the styrene content was 20 ppm. Thus, the measured value of the potential,
It was confirmed that there was a correlation with the water content of the toner at that time (see Table 1 and FIG. 2). When the particle size distribution of the obtained dry toner was measured by a Coulter counter, the weight average particle size was 6.5 μm, and the coefficient of variation was 30%. When the minimum ignition energy of the dried toner was measured by a Hartmann explosion tester, it was 1 mJ, and it was confirmed that the powder was very easily ignited.

Next, 5 parts of 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 above dry toner, and this embodiment containing the above dry toner was added. Of Polymerized Toner 3 was obtained. Further, the toner 5
A two-component developer was prepared by mixing 95 parts by weight of an acrylic-coated ferrite carrier with respect to parts by weight. Next, using this developer, a full-color copier CLC manufactured by Canon
Evaluation of image output on 5,000 continuous sheets was performed using a 500-model remodeling machine. As a result, there was no fog, the image density was stable, and a good image was obtained. In addition, the charge stability was excellent, and the charge amount was not reduced even in a high temperature and high humidity environment, and a stable and good image was obtained.

Example 4 The same colored polymer particles A as used in Example 1 were introduced into a fluidized bed dryer 1 equipped with an electrometer 15 of the type shown in FIG. The exhaust was released to the atmosphere without circulation. As a flowing gas,
Air (oxygen concentration: 21%) was allowed to flow naturally through the inlet 13 and used, and the temperature of the gas introduced into the fluidized-bed dryer 1 was set to 50 ° C. As a result, the potential was less than 1 kV until one hour after the start of drying. One hour later, the powder in the fluidized bed was taken out, and the water content and the styrene content were measured. The water content was 5.2% and the styrene content was 475 ppm.
Met. As in Example 1, the water content was measured by Karl Fischer titration, and the styrene content was measured by gas chromatography.

Since the potential gradually started to increase from one hour after the start of drying, the introduced gas was switched to a gas having a ratio of 93% of nitrogen gas and 7% of oxygen after 15 minutes, and the introduced gas was blown. The drying was continued at a temperature of 50 ° C. Start drying 2
After time, the potential showed 3.2 kV. The powder in the fluidized bed after 2 hours was taken out, and the water content and the styrene content were measured. The water content was 1.3% and the styrene content was 280 p.
pm. When the drying was continued as it was, the potential reached 7.1 kV after 3 hours. The powder in the fluidized bed after 3 hours was taken out, and the water content and the styrene content were measured. As a result, the water content was 0.12% and the styrene content was 25 ppm. As described above, it was confirmed that the measured value of the potential was correlated with the water content of the toner at that time (see Table 1 and FIG. 2). When the particle size distribution of the obtained dry toner was measured by a Coulter counter, the weight average particle size was 6.5 μm, and the coefficient of variation was 30%. When the minimum ignition energy of the dried toner was measured by a Hartmann explosion tester, it was 1 mJ, and it was confirmed that the powder was very easily ignited.

Next, 5 parts of 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 above-mentioned dry toner, and this embodiment containing the above-mentioned dry toner was added. Of Polymerized Toner 4 was obtained. Further, the toner 5
A two-component developer was prepared by mixing 95 parts by weight of an acrylic-coated ferrite carrier with respect to parts by weight. Next, using this developer, a full-color copier CLC manufactured by Canon
Evaluation of image output on 5,000 continuous sheets was performed using a 500-model remodeling machine. As a result, there was no fog, the image density was stable, and a good image was obtained. In addition, the charge stability was excellent, and the charge amount was not reduced even in a high temperature and high humidity environment, and a stable and good image was obtained.

Comparative Example 1 The same colored polymer particles A as used in Example 1 were used in the same flow as that shown in FIG. 1 except that neither the electric field strength meter 14 nor the electrometer 15 was installed. Drying was performed using a layer dryer. The gas naturally flows in air (oxygen concentration 21%) from the inlet 13, the blow-in temperature of the introduced gas is 50 ° C., and the gas is discharged to the atmosphere without circulating the exhaust gas from the exhaust blower 6. After drying for 5 hours, the dried toner was taken out. When the water content and the styrene content of the resulting dry toner were measured, the water content was 0.1% and the styrene content was 50 ppm. In addition, when the same experiment was repeatedly performed,
Due to the natural inflow of air, variations were observed in the water content and the styrene content depending on the environment, particularly humidity, during the experiment. The particle size distribution and minimum ignition energy of the dry toner were the same values as in Example 1. After drying was completed, the surface potential of the powder adhering to the inside of the dryer was measured.
The surface potential was 8 kV, which was dangerous (see Table 1).

Next, 5 parts of 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 dry toner, and the comparative example containing the dry toner was added. Of Polymerized Toner 5 was obtained. Further, the toner 5
A two-component developer was prepared by mixing 95 parts by weight of an acrylic-coated ferrite carrier with respect to parts by weight. Next, using this developer, a full-color copier CLC manufactured by Canon
When the image output evaluation of 5,000 continuous sheets was performed with a 500 remodeling machine, fog gradually occurred, and the image density also decreased.
The image quality was lower than in Example 1. Regarding the charge stability, the charge amount was reduced especially in a high-temperature and high-humidity environment, and the image quality was deteriorated.

[0073]

[Table 1] Table 1: Dry state of Examples and Comparative Examples

[0074]

As described above, according to the present invention, the toner can be stably and safely dried, and the removal of water and unreacted monomers remaining in the toner product can be efficiently performed. Can do well. Further, since oxidation of the dried particles is effectively prevented, a toner having excellent charge stability can be obtained, and a high-quality copied image can be achieved.
In particular, charge stability under high temperature and high humidity can be achieved.

[Brief description of the drawings]

FIG. 1 is a schematic flow chart of a fluidized bed drying apparatus for explaining a method for producing a toner of the present invention.

FIG. 2 shows measured values of electric field strength or electric potential in the embodiment,
FIG. 4 is a diagram illustrating a correlation with a water content of toner particles.

[Explanation of symbols]

 1: Fluidized bed dryer body 2: Bag filter 3: Raw material input port 4: Outlet port 5: Blow blower 6: Exhaust blower 7: Aggregator 8: Heat exchanger 9: Inlet damper 10: Inert gas inlet 11: Exhaust damper 12: Plate 13: Inlet 14: Electric field intensity meter 15: Electrometer 16: Personal computer 17: Oxygen concentration meter

Claims (7)

[Claims] 1. A polymerized toner having a drying step of drying a water-containing wet colored polymer particle containing water obtained by a polymerization method using an aqueous dispersion medium while forming a fluidized layer by floating with a gas. The method for producing a toner for developing an electrostatic charge image according to claim 1, wherein in the drying step, the electric field strength and / or the potential in the fluidized bed is measured to thereby control the drying conditions. Production method. 2. The method according to claim 1, wherein the moisture content of the toner particles in the fluidized bed is indirectly determined from the measured values of the electric field strength and / or the potential in the fluidized bed, and the drying conditions in the fluidized bed are controlled according to the moisture content. Item 3. The method for producing a toner for developing an electrostatic image according to Item 1. 3. The oxygen concentration in the gas introduced into the fluidized bed is set to 1 according to the measured value of the electric field strength and / or the potential in the fluidized bed.
The method for producing an electrostatic image developing toner according to claim 1, wherein the toner is controlled to 2% or less. 4. The oxygen concentration in the gas introduced into the fluidized bed is adjusted to 8 according to the measured electric field strength and / or potential in the fluidized bed.
The method for producing a toner for developing an electrostatic image according to claim 1, wherein the toner is controlled to be equal to or less than%. 5. The method for producing a toner for developing an electrostatic charge image according to claim 1, wherein a main component of the gas is an inert gas. 6. The method according to claim 5, wherein the inert gas is a nitrogen gas. 7. The weight average particle size of the polymerized toner is 10 μm.
The method for producing a toner for developing an electrostatic charge image according to claim 1, wherein: