JP3913005B2 - Toner particle manufacturing method and manufacturing system - Google Patents

Description

【０１７１】
【発明の効果】
本発明によれば、重合法によって得られたトナー粒子中に存在する揮発成分の除去のために、均一にしかも熱を長く受けることないよう、短時間で加熱処理を行うトナー粒子の製造方法が実現できる。
【図面の簡単な説明】
【図１】トナー粒子を熱気流中で粉粒状に分散させ、高速気流と並流に送りながら加熱処理する装置のシステムの一例を示す概略的図である。
【図２】注入媒体を投入しながら、減圧加熱処理を行うシステムの一例を示す概略的図である。
【図３】注入媒体を投入しながら、減圧加熱処理を行うシステムの他の一例を示す概略的図である。
【図４】注入媒体を投入しながら、減圧加熱処理を行うシステムの他の一例を示す概略的図である。
【符号の説明】
１ 吐出ブロアー
２ 熱風発生器
３ 気流分散部
４ 気流抜き出し口
５ ループ型気流加熱管
６ 原料供給装置
７ サイクロン
８ 取り出し口
９ バッグフィルター
１０ 排気ブロアー
１１ 減圧加熱処理容器（リボン翼）
１２ 駆動モーター
１３ 撹拌中心軸
１４ リボン翼
１５ 撹拌翼支持アーム
１６ 連結アーム
１７ 原料供給口
１８ バッグフィルター
１９ コンデンサー
２０ ジャケット
２１ 温水タンク
２２ 減圧ポンプ
２３ 仕切り板
２４ 濾布
２５ 逆洗用ノズル
２６ 注入媒体加熱器
２７ セパレーター
２８ 膨張タンク
２９ 分散盤
３０ 注入媒体噴口
３１ 注入媒体温度計
３２ 注入媒体温度制御器
３３ 減圧加熱処理装置（スクリュー翼）
３４ 駆動アーム
３５ スクリュー式撹拌部材
３６ 注入媒体流量計[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and a system for producing toner particles used in a method for developing a latent image and a toner jet recording method.
[0002]
[Prior art]
As described in U.S. Pat. No. 2,297,691, etc., a number of methods are known for electrophotography. Generally, a photoconductive material is used on a photoreceptor by various means. An electric latent image is formed on the toner image, and then the latent image is developed with toner. If necessary, the toner image is transferred to a transfer material such as paper, and then fixed by heating, pressure, or solvent vapor. Get things. Various methods have been proposed in the past as a method for developing with toner or a method for fixing a toner image, and a method suitable for each image forming process is employed.
[0003]
Conventionally, as a toner used for these purposes, generally, a colorant such as a dye and a pigment is melt-mixed in a thermoplastic resin and uniformly dispersed, and then a toner having a desired particle size is produced by a fine pulverizer and a classifier. I have done it.
[0004]
While this method of manufacture can produce fairly good toners, it has certain limitations, i.e., limited choice of toner materials. For example, the resin colorant dispersion must be sufficiently brittle and capable of being finely pulverized with economically possible production equipment. However, if the resin colorant dispersion is made brittle to satisfy these requirements, the particle size range of the particles formed when actually pulverized at high speed tends to be widened. It is included in the problem. Further, such a highly brittle material is likely to be further pulverized or powdered when used for development in a copying machine or the like. Also, with this method, it is difficult to completely disperse solid fine particles such as a colorant in the resin, and depending on the degree of dispersion, the increase in fog, the decrease in image density, and the color mixing / transparency may be difficult. Care must be taken to disperse as it will cause defects. Further, exposure of the colorant to the fracture surface may cause a change in development characteristics.
[0005]
On the other hand, in order to overcome the problems of the toner by the pulverization method, various toners by various polymerization methods such as the toner by the suspension polymerization method described in Japanese Patent Publication Nos. 36-10231, 43-10799, and 51-14895 are disclosed. And manufacturing methods thereof. For example, in the suspension polymerization method, a monomer composition is obtained by uniformly dissolving or dispersing a polymerizable monomer, a colorant, a polymerization initiator and, if necessary, a crosslinking agent, a charge control agent, and other additives. After that, the monomer composition is dispersed in a continuous phase containing a dispersion stabilizer, for example, an aqueous phase by using a suitable stirrer, and at the same time, a polymerization reaction is performed to obtain toner particles having a desired particle size. obtain.
[0006]
Since this method does not include a pulverization process, the toner does not need to be brittle, a soft material can be used, and the classification process can be omitted, thereby saving energy and saving time. Cost reduction effects such as shortening and improving process yield are significant.
[0007]
In recent years, there has been a demand for multifunctional toners such as high image quality, full color, and energy saving in recent copying machines and printers. For example, in order to cope with high-resolution, digital-sized toner particles with a higher image quality, improved transparency of OHP images with full color, and low-temperature fixing with energy saving, There is a demand for the inclusion of a low softening point substance and the formation of toner particles that are effective in improving the transfer efficiency to a transfer material. As means for realizing these demands, a toner by a polymerization method can be mentioned.
[0008]
On the other hand, as for the polymerization method, including the polymerization method toner, the reaction form of the polymerization reaction system increases as the polymerization proceeds, and it becomes difficult to move radicals and polymerizable monomers. Many body components tend to remain. In particular, in the case of a suspension polymerization method toner, the polymerizable monomer system contains components such as dyes, pigments (particularly carbon black), charge control agents, and magnetic substances that may inhibit the polymerization reaction. Since it exists in a large amount other than the body, unreacted polymerizable monomers are likely to remain.
[0009]
If these toner particles contain many components that act as a solvent for the binder resin as well as the polymerizable monomer, the fluidity of the toner is lowered and the image quality is deteriorated, and the blocking resistance is lowered. . In addition to the performance directly related to the toner, especially when an organic semiconductor is used as the photoreceptor, in addition to the phenomenon of toner fusion to the photoreceptor drum, there is a phenomenon of deterioration of the photoreceptor such as memory ghost and image blurring. This may cause problems. In addition to the matters related to the performance of the product, there is a problem in that the polymerizable monomer component volatilizes and generates a bad odor at the time of fixing.
[0010]
In order to improve the above, as described in JP-A-7-92736, the remaining amount of the polymerizable monomer present in the toner particles is reduced to 500 ppm or less, thereby further improving the image quality. Has been proposed.
[0011]
Furthermore, along with the downsizing and personalization of copiers and printers, the restrictions on the device have increased, the burden on the above-mentioned problems has increased, and the concern for the environment has increased, resulting from toner particles generated by fixing etc. Therefore, it is preferable to reduce the residual amount of polymerizable monomer present in the toner particles to 100 ppm or less.
[0012]
As a method for reducing the residual amount of polymerizable monomer in the toner particles to be further reduced, a known polymerizable monomer consumption promoting means used when the binder resin is produced by a polymerization method is used. can do. For example, as a method of removing the unreacted polymerizable monomer, a method of washing with a highly volatile organic solvent that does not dissolve the toner binder resin but dissolves the polymerizable monomer and / or the organic solvent component; A method of washing with acid or alkali; a solvent component that does not dissolve the foaming agent or polymer is placed in the polymer system, and the resulting toner is made porous to reduce the volatilization area of the internal polymerizable monomer and / or organic solvent component. The main synthetic monomer and / or organic solvent component is volatilized under dry conditions, but it is difficult to select a solvent such as elution of toner constituents due to a decrease in toner capsule properties and the residualness of the solvent. Therefore, the method of volatilizing the polymerizable monomer and / or the organic solvent component under dry conditions is most preferable.
[0013]
In general, toner particles after solid-liquid separation of a suspension in which a polymerization reaction has been completed have generally been freed of volatile components using an air dryer, a vacuum dryer or the like.
[0014]
When removing volatile matter with an air dryer alone, the toner particles are dispersed in a high-speed hot air stream and simultaneously dried while being sent in parallel flow. Although it is possible to supply, it is a very efficient dryer, but since the drying time is instantaneous, it is difficult to remove the unreacted polymerizable monomer.
[0015]
Japanese Patent Application Laid-Open No. 08-160662 proposes a method of vacuum drying toner particles. This drying method has an advantage of drying an object to be dried at a low temperature, but the inside of the apparatus is in a reduced pressure state. As a result, the gas phase stays and the ability to diffuse volatiles is significantly reduced. Therefore, after evaporating and removing moisture, it is very long to remove unreacted polymerizable monomer. It takes time.
[0016]
Japanese Patent Application Laid-Open No. 10-207122 proposes a method of vacuum drying toner particles while injecting an air flow.
[0017]
However, as described in the publication, when an inert gas such as nitrogen or air is used as the gas to be injected, the effect of the carrier gas works and the volatile component does not stay as compared with the case where the gas is simply vacuum dried. However, the dry efficiency of the dry gas such as an inert gas is very small, so that the heat is deprived from the heated toner particles, and the dry efficiency is lowered.
[0018]
For this reason, the drying time is extended and the heat history applied to the toner is lengthened, so that the deformation of the particles and the fusion of the particles occur, and as a result, lumps are generated and the image characteristics are deteriorated.
[0019]
In addition, when the temperature of the airflow is not controlled by heating or the like, the airflow whose temperature has decreased due to adiabatic expansion enters the airflow path, and heat is further removed from the toner particles, further improving the drying efficiency. It will decline.
[0020]
Furthermore, in the gas, the resistance due to diffusion that hinders evaporation is a major factor that determines the drying speed (although it is less than in the case where no carrier gas is used). If it is increased, it is necessary to increase the capacity of the exhaust equipment (mainly the vacuum pump) accordingly, and the production cost becomes great. This is even more true when it comes to mass production.
[0021]
As described above, in this drying method, many problems remain in terms of efficiency, quality, and cost, and it has been a problem for many engineers to solve this problem.
[0022]
[Problems to be solved by the invention]
An object of the present invention is to provide a toner particle manufacturing method and a manufacturing system that solve the above-mentioned problems.
[0023]
Specifically, an object of the present invention is to provide a toner particle manufacturing method and a manufacturing system that uniformly remove volatile components present in toner particles obtained by a polymerization method in a short time.
[0024]
Another object of the present invention is to provide a toner particle manufacturing method and a manufacturing system capable of obtaining a high-quality image free from image defects caused by residual volatile components.
[0025]
It is a further object of the present invention to reduce the energy and cost required to remove the volatiles.
[0026]
[Means for Solving the Problems]
In the present invention, a polymerizable monomer composition containing at least a polymerizable monomer and a colorant is polymerized in an aqueous dispersion medium to produce colored polymer particles, and then washed, dehydrated, The obtained toner particles are supplied to a container that can be depressurized and heated, and are composed of saturated water vapor, superheated water vapor having a temperature lower than the glass transition temperature Tg of the toner particles, and high-humidity air of enthalpy 2500 kJ / kg (dry air) or more. The present invention relates to a method for producing toner particles, wherein a heat treatment under reduced pressure is performed while an injection medium selected from the above is put into the container.
[0027]
The present invention also provides a method of polymerizing a polymerizable monomer composition containing at least a polymerizable monomer and a colorant in an aqueous dispersion medium to produce colored polymer particles, followed by washing and dehydration. Then, the obtained toner particles are supplied to a container that can be depressurized and heated, and an injection medium selected from the group consisting of saturated steam, superheated steam, and high-humidity air of enthalpy 2500 kJ / kg (dry air) or more is supplied to the container. An apparatus for heat treatment under reduced pressure while charging, detecting the temperature A of the injection medium,
The temperature A is as follows:
30 ° C. <A <Glass transition temperature Tg of toner particles
In particular, the present invention relates to a toner particle manufacturing system that performs heat treatment under reduced pressure while controlling temperature.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
As a result of intensive studies, the inventors have supplied colored polymer particles to a container capable of reducing pressure and heating, and (i) saturated steam, (ii) superheated steam, (iii) enthalpy 2500 kJ / kg (dry air) It has been found that volatile components can be removed in a short time by performing heat treatment under reduced pressure while introducing an injection medium that is one of the above humid air.
[0029]
Furthermore, it has been found that the use of the heat treatment method according to the present invention can reduce power during processing, that is, reduce energy and cost.
[0030]
The present invention is advantageous in that water vapor has a relatively small resistance due to diffusion, which particularly hinders evaporation of volatile components present in the toner particles, and has a large amount of heat that can be held compared to dry gas, and is also heat efficient. By paying attention to these two points and using them, it is possible to remove the volatile matter from the toner particles in a very short time (specifically, until it becomes 100 ppm or less). .
[0031]
Further, since a condensable gas such as water vapor (or high-humidity air containing a large amount of water vapor) can be recovered as a liquid by the condensing device, an exhaust device for forming a reduced pressure state is provided. When the dry gas is used as the carrier gas, the entire amount needs to be exhausted, whereas when water vapor is used, only the amount that cannot be recovered by the condensing device may be exhausted.
[0032]
Therefore, the capacity of the exhaust device can be small, and the merit is great compared to the case of using dry gas in terms of energy and cost. In particular, the larger the scale of the heat treatment apparatus, the greater the merit.
[0033]
As described above, the air dryer used in the conventional method for producing polymerized toner is a very efficient dryer, but because the residence time is instantaneous, it is easy to remove moisture. However, there has been a problem that the unreacted polymerizable monomer as a trace component cannot be removed.
[0034]
In addition, when removing volatiles using vacuum drying, the gas phase stays and the power to diffuse volatiles is significantly reduced. In order to remove the body, problems such as a very long drying time have occurred.
[0035]
In addition, in the method of vacuum drying while injecting an air stream (Japanese Patent Laid-Open No. 10-207122), as described above, in the case of a gas having a small amount of heat such as an inert gas, the toner particles are preheated. When the above-mentioned gas is not temperature-controlled by heating or the like, it takes heat away, and if the temperature is not controlled by heating or the like, the airflow whose temperature has decreased due to adiabatic expansion enters the path to send the airflow as it is. As described in the example, as shown in the fact that there is a large difference between the heating temperature and the product temperature of the toner particles, the toner particles are further deprived of heat and the drying efficiency is further reduced. . For this reason, the drying time is extended and the heat history applied to the toner becomes longer, so that the deformation of the particles and the fusion of the particles occur, resulting in the occurrence of lumps and the deterioration of the image characteristics. It was happening.
[0036]
Furthermore, since the above-mentioned gas is a non-condensable gas, it is necessary to exhaust the supplied amount as it is, and the capacity of the exhaust equipment (mainly the decompression pump) for maintaining the reduced pressure becomes very large. There was a problem such as high costs.
[0037]
Hereinafter, the present invention will be described in more detail.
[0038]
The injection medium in the present invention is in a depressurized state in the course of being put into the container where the reduced pressure heat treatment is performed. Strictly speaking, when the injection medium is put into the reduced pressure heat treatment apparatus, the operation decompression degree (heat treatment container Saturated steam, superheated steam, or high-humidity air that has been depressurized to the degree of depressurization within), and the temperature of the injection medium described in the specification is also in this state.
[0039]
In order to prevent condensation, the degree of vacuum used in the present invention is preferably 40 kPa from the viewpoint of obtaining a large temperature difference ΔT between the temperature of the injected injection medium and the boiling point (= saturation temperature). In order to improve the drying efficiency as the degree of vacuum increases, it is more preferably 20 kPa or less, further 15 kPa or less, and particularly preferably 10 kPa or less.
[0040]
Further, “saturated steam” and “superheated steam” used in the present invention exist only in water vapor, and “saturated steam” is steam that is substantially maintained at a saturation temperature corresponding to the operating pressure reduction degree. "Is water vapor superheated above the saturation temperature. In addition, “high humidity air” is mainly occupied by water vapor, but contains air. Since mainly air is used, it is described as air here, but may be an inert gas such as nitrogen. Compared to the dry gas that contains almost no water vapor, which is generally used as a carrier gas, most or all of this is water vapor, so it retains a large amount of heat and has a high enthalpy. They are different in nature.
[0041]
In addition, “enthalpy” of high-humidity air used in the present invention is the total amount of heat of 1 kg of dry air per 1 kg of dry air and water vapor [kg] contained therein, and the unit is “kJ / kg”. (Dry air) ".
[0042]
Furthermore, the high-humidity air used in the present invention has a very large enthalpy because most of the high-humidity air is occupied by water vapor, unlike a gas that hardly contains water vapor.
[0043]
In the present invention, there are no particular limitations because there are various methods for increasing the enthalpy of high-humidity air.
[0044]
The “supply flow rate” of the injection medium used in the present invention is a flow rate fed into the apparatus per unit time and per kg of toner particles, and the unit is “m ^Three / Hr · kg (toner particles) ”.
[0045]
Next, the “moisture content” used in the present invention refers to the mass-based moisture content, that is, the ratio of the moisture mass to the total mass (the sum of the dry toner mass and the moisture mass), and is determined by a heat loss method at 105 ° C. It was.
[0046]
The temperature of the injection medium in the present invention is preferably less than the glass transition temperature Tg of the toner particles.
[0047]
When the steam introduced is brought into contact with an unheated part in the device, the temperature drops, and when it falls to the boiling point (= saturation temperature) corresponding to the degree of decompression during operation, condensation occurs, resulting in drying efficiency. May be reduced. In order to prevent this, it is preferable to take a large temperature difference ΔT between the temperature of the injected injection medium and the boiling point (= saturation temperature) (however, the apparatus / toner particles are sufficiently heated, which may cause a temperature drop). If the water vapor temperature is low, saturated water vapor corresponding to the degree of decompression may be used.) When the water vapor temperature is low, in order to obtain ΔT, a considerably high vacuum is required, and the exhaust equipment and the like are loaded. It is preferable that it is 30 degreeC or more. In addition, when the water vapor is higher than the glass transition temperature Tg of the toner particles, the toner particles are thermally deteriorated, resulting in problems such as fusing and damaging of the particles.
[0048]
The enthalpy of the high humidity air used in the present invention is 2500 kJ / kg (dry air) or higher, preferably 6500 kJ / kg (dry air) or higher, and the enthalpy is 2500 kJ / kg (dry air). If the water vapor is less than that, the amount of heat that can be held is small, so heat is taken away from the preheated toner particles, and the drying efficiency is lowered. As such high-humidity air having high enthalpy, it is preferable to use air having a moisture content of 50% or more because it becomes easy to obtain high-humidity air having high enthalpy. % Or more, and particularly preferably 80% or more.
[0049]
The flow rate of the injection medium in the present invention is 0.01 to 0.5 m. ^Three / Hr · kg (toner particles), preferably 0.04 to 0.27 m ^Three / Hr · kg (toner particles). Within this range, basically, the drying efficiency increases as the injection medium supply flow rate increases. The supply flow rate of the injection medium is 0.01m ^Three If it is smaller than / hr · kg (toner particles), even if the injection medium has a large amount of heat, the amount of heat to be supplied is generally reduced, and the drying efficiency is lowered. On the other hand, the injection medium supply flow rate is 0.5 m. ^Three When the amount is more than / hr · kg (toner particles), a large amount of water vapor flow is required, and thus the degree of vacuum is often lowered. Therefore, the saturation temperature and the vapor temperature ΔT corresponding to the operating pressure reduction degree are small. Therefore, there is a high possibility that condensation will occur.
[0050]
Further, the present invention is considered to be mainly present inside the toner particles in order to cope with the restrictions on the apparatus accompanying the downsizing and personalization of the above-described copying machine, printer, etc. and for the reduction of VOC. Although a trace amount of the polymerizable monomer composition is finally removed, if the toner particles contain a large amount of moisture, the moisture is present on the particle surface. Can not be reduced. Therefore, in order to further improve the volatile matter removal efficiency, it is preferable to remove the water contained in the toner particles in advance.
[0051]
Specifically, the water content of the toner particles supplied to the reduced pressure heat treatment is preferably 3.0% or less, more preferably 1.0% or less. In order to control the water content of the toner particles to 3.0% or less, in the present invention, it is preferable to perform preliminary heat treatment before performing the heat treatment under reduced pressure. As the preliminary heat treatment, for example, there is a method in which the heat treatment is preliminarily performed while being dispersed in a high-speed hot air stream and simultaneously sent in parallel flow. By using a heat treatment apparatus capable of continuously supplying toner particles into a high-speed hot air stream, the water content of the toner particles is reduced to 3.0% or less in advance, and the temperature is increased by the preliminary heat treatment. More preferably, the toner particles are subjected to a heat treatment under reduced pressure while maintaining the temperature.
[0052]
As a result, a process governed by the amount of heat given from the heat transfer surface in the reduced-pressure heating process is completed in advance both when removing moisture that requires a large amount of latent heat of evaporation and when raising the temperature of a material that requires a large amount of sensible heat. By reducing the difference between temperature and product temperature (with less heat transfer), not only can the processing time be shortened, but it is also loaded into a device typified by a vacuum heat treatment device with a heat transfer surface. Eliminate the disadvantage that the ratio of the heat transfer area to the sample becomes smaller as the scale becomes larger, that is, the drying time required for the small scale will take longer for the large scale. In addition, toner particles with less deterioration can be provided.
[0053]
In the present invention, the product temperature of the toner particles when starting the reduced pressure heat treatment is preferably 30 to 60 ° C.
[0054]
When the product temperature of the toner particles is less than 30 ° C., as described above, a large amount of heat energy is required to raise the temperature of the toner particles during the heat treatment under reduced pressure. Since the ratio of the heat transfer area with respect to is reduced, a longer processing time is required.
[0055]
Conversely, if the product temperature of the toner particles exceeds 60 ° C., the toner particles may aggregate and fuse with each other, causing problems in the product and causing fusion within the apparatus, which is very important for cleaning and the like. Takes a lot of effort.
[0056]
As an apparatus for performing heat treatment instantaneously while being sent in parallel flow in a high-speed hot air flow, used as a preliminary heat treatment device of the present invention, for example, has a loop type air flow heating tube 5 as shown in FIG. Although a heat processing apparatus is mentioned, it does not restrict | limit in particular.
[0057]
First, the air supplied from the discharge blower 1 is heated and compressed to a predetermined temperature in the hot air generator 2 and discharged from the airflow dispersion unit 3 at supersonic speed. The processed material supplied from the raw material supply device 6 is dispersed by the discharged air flow and processed instantaneously (0.5 to several tens of seconds) in the loop type air flow heating tube 5. The air flow outlet 4 is provided inside the loop type air flow heating tube 5 so as to classify particles in a coherent state and dispersed and close to single particles by the Coanda effect. The classified particles are separated from the air flow by the cyclone 7 and discharged from the take-out port 8. The air flow can be discharged out of the system from the exhaust blower 10 via the bag filter 9.
[0058]
Further, coarse particles in the particles discharged from the loop type airflow heating tube 5 are classified by a separate classifier and returned to the raw material supply device 6, and only particles in a certain particle size range are supplied to the cyclone 7 to obtain desired toner particles. By obtaining, classification and heat treatment can be performed continuously.
[0059]
In addition to the loop type described above, the pipe type of the airflow heat treatment apparatus is a straight pipe type, with an enlarged inner cylinder to increase the residence time, and by depositing particles on the bottom of the horizontal pipe by giving a vortex motion. Although various types of heat treatment tubes such as a type for preventing airflow can be used, an airflow heat treatment apparatus having a loop-type airflow heating tube 5 as shown in FIG. 1 is most preferable.
[0060]
In the present invention, it is preferable to use compressed air heated to 40 to 150 ° C., preferably 60 to 120 ° C., for the heat treatment with a hot air stream. When the heating temperature is lower than 40 ° C., the drying efficiency is lowered. When the heating temperature is higher than 150 ° C., the toner is fused, which is not preferable.
[0061]
Specific examples of such an apparatus include a flash jet dryer (manufactured by Seishin Enterprise) and a flash dryer (manufactured by Hosokawa Micron).
[0062]
In addition, there is no particular limitation on the method of performing the reduced pressure heat treatment while maintaining the temperature of the toner particles heated by the preliminary heat treatment, but for example, between the preliminary heat treatment step and the reduced pressure heat treatment step, A method of providing a hopper or the like having a heat retaining function can be used.
[0063]
Next, the reduced-pressure heat treatment apparatus used in the present invention can be used without particular limitation as long as it is an apparatus that can be reduced in pressure and heated and can be charged with the above-described injection medium, detects the temperature of the injection medium, It is more preferable that the vapor temperature A is systematized so that the temperature is controlled such that “30 ° C. <A <glass transition temperature Tg of toner particles”.
[0064]
For example, a reduced-pressure heat treatment system having a schematic side view shown in FIGS. 2 to 4 is preferably used.
[0065]
Hereinafter, the reduced pressure heat treatment system of the embodiment shown in FIGS. 2 to 4 will be described in detail.
[0066]
In the reduced pressure heat treatment system shown in FIG. 2, the toner particles are supplied into the inverted conical reduced pressure heat treatment container 11 to perform the reduced pressure heat treatment. A stirring center shaft 13 that can be driven by a drive motor 12 extends in the container center longitudinal axis in the container, and a ribbon blade 14 having a single spiral structure around it, and a connection supported by a stirring blade support arm 15 outside thereof. The arm 16 has a structure attached along the wall surface.
[0067]
By rotating the ribbon blade 14, stirring and dispersion can be repeatedly applied while lifting the toner particles from below to above, so that the raw materials in the container can be efficiently stirred and mixed throughout. The connection arm 16 will be described later.
[0068]
Further, as shown in FIG. 2, a bag filter 18 and then a condenser 19 are connected to an upper portion of the container 11 to a raw material supply port 17 for supplying toner particles and an exhaust path for reducing the pressure in the container. Has been.
[0069]
Further, as shown in FIG. 2, a jacket 20 is attached around the above-described reduced-pressure heat treatment container so that the temperature in the container is appropriately controlled and heat treatment can be performed at a desired temperature. ing. For this reason, a gap is formed between the outer wall of the container and the inner wall of the jacket 20, and the jacket is made of a hot water tank 21 so that heated steam and cooling water can be passed through the gap. Hot water, steam, or cooling water supply can be supplied, and at the same time, discharge paths for hot water, steam, and cooling water are provided.
[0070]
Further, pressure reduction in the container is performed by exhausting water vapor in the container from the exhaust port through the bag filter 18 and the condenser 19 by the decompression pump 22. As shown in FIG. 2, the bag filter 18 is partitioned into two upper and lower chambers by a partition plate 23. A cylindrical filter cloth 24 is suspended below the partition plate, and an exhaust path connected to the condenser 19 is provided above the partition plate and backwashed to a position above the center of the filter cloth 24. A nozzle 25 is disposed. The backwash nozzle 25 is for intermittently jetting nitrogen, air, or the above injection medium (preferably heated nitrogen and air and the above injection medium) to wash the filter cloth 24 by back pressure.
[0071]
The supply source of the water vapor into the container is not particularly limited, but in general, it is often supplied from a boiler generator and passes through the injection medium flow meter 36 and heated by the injection medium heater 26. (If necessary, saturated water can be removed by the separator 27), and the pressure is reduced to near the operating pressure reduction level by the expansion tank 28. On the other hand, from the lower part of the apparatus, a disperser 29 for uniformly dispersing the injection medium is provided. And uniformly supplied into the apparatus. The other passes from the upper part of the apparatus to the inside of the stirring center shaft 13, then the stirring blade support arm 15, and then the connecting arm 16, and the inside of the inside is hollow and communicated, and a plurality of injection medium nozzle holes 30 provided in the connecting arm 16. The above-mentioned injection medium is sprayed from the wall toward the wall surface. Accordingly, it is possible to prevent toner particles from adhering to the wall surface, and it is possible to prevent the heat transfer efficiency from the wall surface from being lowered.
[0072]
The temperature of the injection medium expanded in the expansion tank 28 is detected by the injection medium thermometer 31 and controlled by the injection medium temperature controller 32.
[0073]
Further, the method of changing the injection medium to the reduced pressure state is not limited to the above-described method. For example, instead of installing the expansion tank, the pipe diameter may be increased.
[0074]
By spraying the injection medium uniformly from below, the toner particles are prevented from blocking at the lower part of the apparatus, and by spraying the injection medium from the connecting arm 16 toward the wall surface, the toner particles adhere to and stay on the wall surface. In addition to improving heat transfer efficiency by efficiently and constantly renewing particles near the wall surface, the toner particles in the container are blocked by heat generated by agitation due to wall surface adhesion and fusion. It is possible to simultaneously prevent the heat of stirring from accumulating and excessively raising the temperature (raising the temperature above the heating temperature).
[0075]
The injection medium supplied into the vacuum heat treatment container is vapor mixed with volatile components from the toner particles, passes through the bag filter 18, is condensed and recovered by the next condenser 19, and the vapor that could not be condensed is decompressed. It is discharged out of the system through the pump 22. In a state in which the water content of the toner particles is substantially removed, the volatile components generated from the toner particles are very small, so that most of the toner particles are controlled by the supplied injection medium. As a result, most of the condensable injection medium is recovered as water by the condenser 19, so that the capacity of the decompression pump 22 can be small as described above.
[0076]
Further, the reduced-pressure heat treatment apparatus 37 shown in FIG. 4 has only the ribbon blade having a single spiral structure without the connecting arm portion of FIG. As the connecting arm is removed, the diameter of the ribbon wing increases and the distance between the wall and the ribbon decreases. For this reason, the effect of lifting the toner particles near the wall surface from below to above is strong. About the structure of the other part of the heat processing system shown in FIG. 4, since supply of water vapor | steam is performed only from an apparatus bottom part, since the decompression heat processing system of FIG. Omitted.
[0077]
On the other hand, the reduced-pressure heat treatment apparatus 33 shown in FIG. 3 is provided with a screw-type stirring member 35 connected to the drive motor 12 disposed on the upper portion of the inverted conical container via the drive arm 34, and the stirring The member is configured to rotate along the inner peripheral surface of the container while rotating. For this reason, in the reduced-pressure heat treatment apparatus shown in FIG. 3, since the toner particles in the container are repeatedly stirred and dispersed while being lifted upward from below, the toner particles are efficiently stirred and mixed throughout the container. . About the structure of the other part of the heat processing system shown in FIG. 3, since supply of water vapor | steam is performed only from an apparatus bottom part, since the decompression heat processing system of FIG. 2 is common, description of this part is demonstrated. Omitted.
[0078]
As the reduced-pressure heat treatment apparatus to which the production method of the present invention can be applied, in addition to the apparatus of the embodiment used in FIGS. 2 and 3, specifically, a Nauter mixer (manufactured by Hosokawa Micron), a ribocorn mixer ( Okawara Seisakusho Co., Ltd.), PV mixer (Shinko Pantech Co., Ltd.), vacuum stirring and drying device Inox system (Paulec Co., Ltd.), SV mixer (Shinko Pantech Co., Ltd.) and the like.
[0079]
Next, the toner particles according to the present invention are preferably toner particles having a fine particle diameter in order to faithfully reproduce finer latent image dots from the demand for higher image quality. A toner particle having a weight average diameter measured by (manufactured by Coulter) of 4 to 10 μm and a number variation coefficient of less than 35% is particularly preferable.
[0080]
When the toner particles are less than 4 μm, a large amount of residual toner is generated on the photosensitive member or intermediate transfer member due to poor transfer efficiency, which is likely to cause uneven image unevenness due to fogging or transfer failure.
[0081]
Further, when the weight average particle diameter of the toner particles exceeds 10 μm, fusion to the member tends to occur, and when the number variation coefficient of the toner exceeds 35%, the tendency is further increased.
[0082]
As the method for producing the toner particles of the present invention, the suspension polymerization method or emulsion polymerization method described in JP-B-36-10231, JP-A-59-53856, and JP-A-59-61842. It is possible to produce toner particles using a method that directly produces toner using
[0083]
In the present invention, a so-called seed polymerization method in which a monomer is further adsorbed to the polymer particles once obtained and then polymerized using a polymerization initiator can be suitably used in the present invention.
[0084]
In the present invention, polymerizable monomers that can be used include styrene monomers such as styrene, o (m-, p-)-methylstyrene, m (p-)-ethylstyrene; (meth) acrylic Methyl methacrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, octyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, (meth) acrylic acid (Meth) acrylic ester monomers such as behenyl, 2-ethylhexyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate; butadiene; isoprene; cyclohexene; (meth) acrylonitrile A vinyl monomer such as acrylic amide. Moreover, it may be used in combination of two or more as required.
[0085]
In the present invention, in order to encapsulate the low softening point substance by the outer shell resin obtained by polymerizing the polymerizable monomer as described above, in addition to the outer shell resin, a polar resin is further added as a polymerizable monomer. It is particularly preferable to add it to the body composition. As the polar resin used in the present invention, a copolymer of styrene and (meth) acrylic acid, a maleic acid copolymer, a saturated or unsaturated polyester resin, and an epoxy resin are preferably used. The polar resin is particularly preferably one containing no unsaturated group capable of reacting with the outer shell resin or the monomer. In the case of containing a polar resin having an unsaturated group, a crosslinking reaction occurs with the monomer forming the outer shell resin layer, resulting in an extremely high molecular weight as a full color toner, black toner, magenta toner, cyan toner and yellow toner. In the case of a full color toner using four color toners, it is not preferable because it is disadvantageous in terms of color mixing.
[0086]
The low softening point substance used in the present invention is preferably a compound having a main maximum peak value measured in accordance with ASTM D3418-8 of 40 to 90 ° C. When the maximum peak is less than 40 ° C., the self-aggregation force of the low softening point substance becomes weak, and as a result, the high temperature offset resistance becomes weak, which is not preferable for a full color toner. On the other hand, when the maximum peak exceeds 90 ° C., the fixing temperature becomes high, and it becomes difficult to appropriately smooth the surface of the fixed image, which is not preferable from the viewpoint of mixing properties. Furthermore, when toner is obtained by direct polymerization, granulation and polymerization are carried out in an aqueous system, so if the temperature at the maximum peak value is high, a low softening point substance mainly precipitates during granulation and inhibits the suspension system. Therefore, it is not preferable. Specifically, paraffin wax, polyolefin wax, Fischer tropish wax, amide wax, higher fatty acid, ester wax and derivatives thereof or graft / block compounds thereof can be used.
[0087]
As the colorant used in the present invention, a black colorant that is toned in black using carbon black, a magnetic material, and the following yellow / magenta / cyan colorant is used.
[0088]
As the yellow colorant, compounds typified 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, 17, 62, 74, 83, 93, 94, 95, 109, 110, 111, 128, 129, 147, 168 are preferably used.
[0089]
As the magenta colorant, condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds are used. Specifically, C.I. I. Pigment Red 2, 3, 5, 6, 7, 23, 48: 2, 48: 3, 48: 4, 57: 1, 81: 1, 122, 144, 146, 166, 169, 177, 184, 185, 202, 206, 220, 221, and 254 are preferably used.
[0090]
As the cyan colorant, copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds, basic dye lake compounds can be used. Specifically, C.I. I. Pigment Blue 1, 7, 15, 15: 1, 15: 2, 15: 3, 15: 4, 60, 62, 66 can be preferably used.
[0091]
These colorants can be used alone or in combination and further in the form of a solid solution. The colorant of 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 mass with respect to 100 parts by mass of the resin.
[0092]
When a magnetic material is used as the black colorant, 40 to 150 parts by mass are added to 100 parts by mass of the resin, unlike other colorants.
[0093]
As the charge control agent used in the present invention, known ones can be used. However, a charge control agent that is colorless, has a high toner charging speed, and can stably maintain a constant charge amount is preferable. Further, when the direct polymerization method is used in the present invention, a charge control agent having no polymerization inhibition and no solubilized product in an aqueous system is particularly preferable. As specific compounds, salicylic acid, naphthoic acid, dicarboxylic acid metal compounds, sulfonic acid, polymer compounds having carboxylic acid in the side chain, boron compounds, urea compounds, silicon compounds, and calixarenes are used as negative compounds. In addition, as a positive system, a quaternary ammonium salt, a polymer compound having the side chain of the quaternary ammonium salt, a guanidine compound, and an imidazole compound are preferably used. The charge control agent is preferably 0.5 to 10 parts by mass with respect to 100 parts by mass of the resin. However, in the present invention, it is not essential to add a charge control agent. When a two-component development method is used, frictional charging with a carrier is used, and even when a non-magnetic one-component blade coating development method is used, the blade It is not always necessary to include a charge control agent in the toner by actively utilizing frictional charging with the member or the sleeve member.
[0094]
Examples of the polymerization initiator that can be used in the polymerized toner according to the present invention include 2,2′-azobis- (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1,1 ′. -Azo or diazo polymerization initiators such as azobis- (cyclohexane-1-carbonitrile), 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, azobisisobutyronitrile; benzoyl peroxide Peroxide-based polymerization initiators such as methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, 2,4-dichlorobenzoyl peroxide, lauroyl peroxide are used. The addition amount of the polymerization initiator varies depending on the target degree of polymerization, but generally 0.5 to 20% by mass is added to the monomer. The kind of the polymerization initiator varies slightly depending on the polymerization method, but is used alone or in combination with reference to the 10-hour half-life temperature.
[0095]
In order to control the degree of polymerization, a known crosslinking agent, chain transfer agent, polymerization inhibitor and the like can be further added and used.
[0096]
In the polymerized toner according to the present invention, particularly when using suspension polymerization using a dispersant, the dispersant used is an inorganic compound such as tricalcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, calcium carbonate. , Magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate, bentonite, silica, and alumina. As organic compounds, polyvinyl alcohol, gelatin, methylcellulose, methylhydroxypropylcellulose, ethylcellulose, sodium salt of carboxymethylcellulose, polyacrylic acid and salts thereof, and starch can be used by dispersing in an aqueous phase. These stabilizers are preferably used in an amount of 0.2 to 20 parts by mass with respect to 100 parts by mass of the polymerizable monomer.
[0097]
Among these stabilizers, when an inorganic compound is used, a commercially available one may be used as it is, but in order to obtain fine particles, the inorganic compound may be produced in a dispersion medium. For example, in the case of tricalcium phosphate, a sodium phosphate aqueous solution and a calcium chloride aqueous solution may be mixed under high stirring.
[0098]
Moreover, you may use 0.001-0.1 mass part surfactant for fine dispersion of these stabilizers. This is to promote the intended action of the above dispersion stabilizer, and specific examples thereof include sodium dodecylbenzene sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, lauric acid. Examples include sodium, potassium stearate, and calcium oleate.
[0099]
In the toner manufacturing method of the present invention, the toner can be specifically manufactured by the following manufacturing method.
[0100]
That is, a release agent composed of a low softening point substance, a colorant, a charge control agent, a polymerization initiator and other additives are added to the polymerizable monomer, and the mixture is uniformly dissolved or dispersed by a homogenizer, an ultrasonic disperser or the like. The monomer system is dispersed in an aqueous phase containing a dispersion stabilizer by a usual stirrer or CLEARMIX, homomixer, homogenizer or the like. Preferably, granulation is performed by adjusting the stirring speed and time so that the monomer droplets have a desired toner particle size. Thereafter, stirring may be performed to such an extent that the particle state is maintained and the sedimentation of the particles is prevented by the action of the dispersion stabilizer. The polymerization is preferably carried out at a polymerization temperature of 40 ° C. or higher, generally 50 to 90 ° C. In addition, the temperature may be raised in the latter half of the polymerization reaction, and in order to remove unreacted polymerizable monomers and by-products that cause odor during toner fixing, the latter half of the reaction, or the completion of the reaction. A part of the aqueous medium may be distilled off later. After completion of the reaction, the produced toner particles are recovered by washing and filtration and dried by the drying method of the present invention. In the suspension polymerization method, it is usually preferable to use 300 to 3000 parts by mass of water as a dispersion medium with respect to 100 parts by mass of the monomer system.
[0101]
In the present invention, it is preferable that the Tg of the toner particles thus obtained is adjusted to be 40 to 75 ° C. When the temperature is lower than 40 ° C., there is a problem in terms of storage stability of the toner and durability of the developer. On the other hand, when the temperature exceeds 75 ° C., the fixing point is increased. Insufficient color mixing results in poor color reproducibility, and further reduces the transparency of the OHP image, which is undesirable from the standpoint of high image quality.
[0102]
Below, the measuring method of each physical-property value used by this invention is described.
[0103]
1. Measuring method of toner particle Tg
In this invention, it measured with the following method using the differential thermal analysis measuring device (DSC measuring device) and DSC-7 (made by Perkin-Elmer). First, a measurement sample is accurately weighed in an amount of 5 to 20 mg, preferably about 10 mg. And this is put into an aluminum pan, and an empty aluminum pan is used as a reference, and the temperature rising rate is 10 ° C./min. Measure at room temperature and humidity. As a result, in this temperature rising process, before the endothermic peak of the main peak in the temperature range of 40 to 100 ° C. and after it has come out, the intersection point of the midpoint of the baseline and the differential heat curve is represented in the present invention. The glass transition temperature Tg.
[0104]
2. Method for measuring moisture content
The water content of the toner of the present invention was measured by a heat loss method at 105 ° C. using a MA40 electronic moisture meter (manufactured by Sartorius).
[0105]
3. Measurement of residual amount of polymerizable monomer and organic solvent remaining in toner particles
The remaining amount of the polymerizable monomer and the organic solvent remaining in the toner particles was determined by using a solution of 0.3 g of toner dissolved in 10 g of acetone and applying an ultrasonic shaker for 30 minutes, and then leaving it for one day. Next, the product was filtered through a 0.5 μm filter, and each was measured by an absolute calibration curve method under the following conditions by gas chromatography.
[0106]
G. C. conditions
Measuring device: HEWLETT PACKARD HP6890 series
Capillary column: (25 m × 0.2 mm, HP-INNOWAX, film thickness: 0.4 μm)
Detector: FID He flow rate 25 ml / min
Injection temperature: 200 ° C
Detector temperature: 200 ° C
Column temperature: Temperature raised at a rate of 50 ° C to 10 ° C / min for 15 minutes
Implanted sample volume: 2 μl
4). Measuring method of toner particle size distribution
The particle size distribution can be measured by various methods. In the present invention, the particle size distribution was performed using a Coulter counter.
As a measuring device, Coulter Counter TA-II type or Coulter Multisizer II (manufactured by Coulter Inc.) is used. As the electrolyte, first grade sodium chloride is used to prepare an approximately 1% NaCl aqueous solution. For example, ISOTON-II (manufactured by Coulter Scientific Japan) can be used. As a measuring method, 0.1 to 5 ml of a surfactant, preferably alkylbenzenesulfonate is added as a dispersant to 100 to 150 ml of the electrolytic aqueous solution, and 2 to 20 mg of a measurement sample is further added. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and the volume and number of toners are measured by using the measuring apparatus with a 100 μm aperture as the aperture. Distribution was calculated. Then, the weight-based weight average particle diameter (D4) obtained from the volume distribution according to the present invention (the median value of each channel is a representative value for each channel) was obtained. The particle size distribution of the toner particles can be measured by various methods. In the present invention, the particle size distribution was performed using a Coulter counter.
[0107]
【Example】
Hereinafter, the present invention will be specifically described by way of examples.
[0108]
<Example 1>
0.1 mol / liter-Na in 710 parts by mass of ion-exchanged water _Three PO _Four After 450 parts by mass of the aqueous solution was added and heated to 60 ° C., the mixture was stirred at 3,500 revolutions / minute using CLEARMIX (M Technique Co., Ltd.). To this, 1.0 mol / liter-CaCl ₂ Add 68 parts by mass of aqueous solution and add Ca. _Three (PO _Four ) ₂ An aqueous medium containing was obtained.
[0109]
On the other hand, the dispersoid system is
・ 165 parts by mass of styrene monomer
・ 35 parts by mass of n-butyl acrylate
・ C. I. Pigment Blue 15: 3 10 parts by mass
・ 20 parts by weight of saturated polyester
・ 3 parts by weight of metal salicylic acid compound
・ Ester wax 25 parts by mass
Among the above prescriptions, C.I. I. Pigment Blue 15: 3, a salicylic acid metal compound and 100 parts by mass of a styrene monomer were dispersed for 3 hours using an attritor (manufactured by Mitsui Miike Chemical Co., Ltd.) to obtain a colorant dispersion. Next, the rest of the above formulation was added to the colorant dispersion, heated to 60 ° C., and dissolved and mixed for 30 minutes. In this, 10 parts by mass of 2,2′-azobis (2,4-dimethylvaleronitrile) as a polymerization initiator was dissolved to prepare a polymerizable monomer composition.
[0110]
The polymerizable monomer composition was put into the aqueous dispersion medium and granulated for 15 minutes while maintaining the rotation speed. Then, the stirrer was changed from the high-speed stirrer to the propeller stirring blade, the internal temperature was raised to 80 ° C., and the polymerization was continued at 50 rpm for 10 hours. Next, distillation was performed for 4 hours under the conditions of an internal temperature of 80 ° C. and an internal pressure of 47.3 kPa. After completion of distillation, the slurry is cooled, diluted hydrochloric acid is added, and Ca _Three (PO _Four ) ₂ Then, filtration, washing with water and crushing were performed to obtain wet colored polymer particles (toner particles) having a water content of 15% and a weight average diameter of 7.8 μm.
[0111]
At this time, the amount of the polymerizable monomer remaining in the toner particles was 850 ppm.
[0112]
The wet colored polymer particles thus obtained were preliminarily heated in an air flow heat treatment section having a pipe diameter of 0.1016 m in the same manner as in FIG. The volatile matter was removed using the reduced-pressure heat treatment system according to the second aspect.
[0113]
As preliminary heat treatment, air flow heat treatment is as follows: hot air temperature: 80 ° C., supply air volume: 480 m ^Three / Hr, toner supply amount: 70 kg / hr. The water content after the treatment was 0.22%, and the amount of the unreacted polymerizable monomer was 840 ppm. At this time, the glass transition temperature Tg of the toner particles was measured and found to be 62 ° C.
[0114]
The heat treatment conditions under reduced pressure are as follows: heating temperature: 45 ° C., degree of pressure reduction during processing: 3 kPa, charge amount 30 kg, temperature 45 ° C., enthalpy about 14000 kJ / kg (dry air), moisture content about 90% The supply flow rate is 0.13m ^Three / Hr · kg (toner particles) was added.
[0115]
The toner particle product temperature at the start of the reduced pressure heat treatment was 22 ° C.
[0116]
Under the above conditions, heat treatment under reduced pressure was performed for 3 hours.
[0117]
At the end of the treatment, the water content was 0.20% and the amount of unreacted polymerizable monomer was 45 ppm. Further, the yield of the toner particles after discharge was 90% based on the time when the reduced pressure heat treatment was introduced.
[0118]
The specific surface area by the BET method is 200 m with respect to 100 parts by mass of the obtained toner particles. ² A developer was prepared by externally adding 1.5 parts by mass of hydrophobic silica having a / g content.
[0119]
Using this developer, an image printing test was conducted in a 23 ° C./65% RH environment using a Canon color printer Color Laser Shot-2030 remodeled machine. There was no change in the image density after endurance, and a high-quality image with no voids was obtained. Further, problems such as toner fusion and memory ghost did not occur on the photoconductor which is an organic semiconductor. Further, double-sided images were formed, but no occurrence of offset was observed on the front and back surfaces of the transfer material. Further, when an image was formed on an OHP sheet, an image with good transparency was obtained.
[0120]
Further, when a similar image printing test was performed in an environment of 30 ° C./80% RH, similarly good results were obtained.
[0121]
<Example 2>
Until the preliminary heat treatment, the toner particles obtained in the same manner as in Example 1 were treated with a reduced-pressure heat treatment system having the same mode as in FIG.
[0122]
The heat treatment conditions under reduced pressure are as follows: heating temperature: 45 ° C., decompression degree during processing: 3 kPa, charge amount 30 kg, temperature 45 ° C., enthalpy approximately 2500 kJ / kg (dry air), moisture content 60% The supply flow rate is 0.13m ^Three / Hr · kg (toner particles) was added.
[0123]
The toner particle product temperature at the start of the reduced pressure heat treatment was 22 ° C., and the reduced pressure heat treatment was performed for 3 hours under the above conditions.
[0124]
At the end of drying, the amount of unreacted polymerizable monomer was 95 ppm. Further, the yield of toner particles after discharge was 89%.
[0125]
Further, the obtained toner particles were externally added with the same hydrophobic silica as used in Example 1 to obtain a developer, and the same image formation evaluation as in Example 1 was performed. In the image printing under an 80% RH environment, solid white spots caused by transfer defects slightly occurred from about 9,500 sheets.
[0126]
<Example 3>
Until the preliminary heat treatment, the toner particles obtained in the same manner as in Example 1 were treated with a reduced-pressure heat treatment system having the same mode as in FIG.
[0127]
The heat treatment conditions under reduced pressure are as follows: heating temperature: 45 ° C., degree of pressure reduction during processing: 3 kPa, charge amount of 30 kg, superheated steam at a temperature of 45 ° C. and a steam pressure of 3 kPa, and a steam supply flow rate of 0.13 m. ^Three / Hr · kg (toner particles) was added.
[0128]
The toner particle product temperature at the start of the reduced pressure heat treatment was 22 ° C., and the reduced pressure heat treatment was performed for 3 hours under the above conditions.
[0129]
At the end of drying, the amount of unreacted polymerizable monomer was 25 ppm. Further, the yield of toner particles after discharge was 90%.
[0130]
Further, the obtained toner particles were externally added with the same hydrophobic silica as used in Example 1 to obtain a developer, and the same image formation evaluation as in Example 1 was performed. As well as, good results were obtained.
[0131]
<Example 4>
Until the preliminary heat treatment, the toner particles obtained in the same manner as in Example 1 were used for 3 hours under the same conditions as in Example 3 using a vacuum heat treatment apparatus having a working capacity of 100 liters in the same manner as in FIG. Processed.
[0132]
The toner particle product temperature at the start of the reduced pressure heat treatment was 22 ° C.
[0133]
At the end of drying, the amount of unreacted polymerizable monomer was 40 ppm. Further, the yield of toner particles after discharge was 70%.
[0134]
Further, the obtained toner particles were externally added with the same hydrophobic silica as used in Example 1 to obtain a developer, and the same image formation evaluation as in Example 1 was performed. As well as, good results were obtained.
[0135]
<Example 5>
Until the preliminary heat treatment, the toner particles obtained in the same manner as in Example 1 were used for 3 hours under the same conditions as in Example 3 using a vacuum heat treatment apparatus having a working capacity of 100 liters in the same manner as in FIG. Processed.
[0136]
The toner particle product temperature at the start of the reduced pressure heat treatment was 22 ° C.
[0137]
At the end of drying, the amount of unreacted polymerizable monomer was 25 ppm. Further, the yield of toner particles after discharge was 83%.
[0138]
Further, the obtained toner particles were externally added with the same hydrophobic silica as used in Example 1 to obtain a developer, and the same image formation evaluation as in Example 1 was performed. As well as, good results were obtained.
[0139]
<Example 6>
A heat treatment under reduced pressure was performed under the same apparatus and heat treatment conditions as in Example 3 except that a pulverized product having a water content of the toner particles after the preliminary heat treatment of 2.8% was used.
[0140]
The toner particle product temperature at the start of the reduced pressure heat treatment was 20 ° C., and the amount of unreacted polymerizable monomer was 50 ppm at the end of drying. Further, the yield of toner particles after discharge was 88%.
[0141]
Further, the obtained toner particles were externally added with the same hydrophobic silica as used in Example 1 to obtain a developer, and the same image formation evaluation as in Example 1 was performed. As with, good image output results were obtained.
[0142]
<Example 7>
Until the crushing step, the toner particles obtained in the same manner as in Example 1 are treated as a preliminary heat treatment under the same heat treatment system and conditions as in Example 3, and the moisture content remains 0.22%. Toner particles in which the amount of the unreacted polymerizable monomer is 840 ppm, the glass transition temperature Tg of the toner particles is 62 ° C., and the particle temperature immediately after the treatment is 40 ° C. are maintained in the same manner as in Example 3. The treatment was performed for 3 hours using the reduced pressure heat treatment apparatus and conditions.
[0143]
At the end of the heat treatment, the amount of unreacted polymerizable monomer was less than the measurement limit of 20 ppm. Further, the yield of toner particles after discharge was 91%.
[0144]
Further, the obtained toner particles were externally added with the same hydrophobic silica as used in Example 1 to obtain a developer, and the same image formation evaluation as in Example 1 was performed. Good results similar to those obtained were obtained.
[0145]
<Example 8>
Until the preliminary heat treatment, the toner particles obtained in the same manner as in Example 1 were treated with a reduced-pressure heat treatment system having the same mode as in FIG.
[0146]
The heat treatment conditions under reduced pressure are as follows: heating temperature: 45 ° C., degree of decompression during processing: 3 kPa, charge amount 30 kg, superheated steam with a temperature of 45 ° C. and a vapor pressure of 3 kPa, and a supply flow rate of 0.029 m. ^Three / Hr · kg (toner particles) was added.
[0147]
The toner particle product temperature at the start of the reduced pressure heat treatment was 22 ° C., and the reduced pressure heat treatment was performed for 3 hours under the above conditions.
[0148]
At the end of drying, the amount of unreacted polymerizable monomer was 75 ppm. The toner particle yield after discharge was 93%.
[0149]
Further, the obtained toner particles were externally added with the same hydrophobic silica used in Example 1 to obtain a developer, and the same image formation evaluation as in Example 1 was performed. The same image output result as in 1 was obtained.
[0150]
<Comparative Example 1>
Using toner particles having a water content of 0.22% after the preliminary heat treatment in Example 1 and a residual polymerizable monomer amount of 840 ppm, 100 parts of the toner particles were used in Example 1. When 1.5 parts of the hydrophobic silica used was mixed to obtain a developer, and the same image formation evaluation as in Example 1 was performed, a solid portion white spot due to transfer failure occurred from about 500 sheets, and 700 The image density decreased from about the number of sheets. Further, image defects due to toner fusion to the photoreceptor occurred at about 1,000 sheets under an environment of 30 ° C./80% RH.
[0151]
<Comparative example 2>
Implemented except that 30 ° C, 80% RH air was heated to 45 ° C under reduced pressure, low humidity air with an enthalpy of about 100 kJ / kg (dry air) and water content of about 5% was put into the vacuum heat treatment equipment Using the same toner particles as in Example 1, the same heat treatment conditions as in Example 3 were used under the same heat treatment conditions using the same preliminary heat treatment apparatus and reduced pressure heat treatment apparatus.
[0152]
The toner particle product temperature at the start of the reduced pressure heat treatment was 22 ° C.
[0153]
At the end of the heat treatment under reduced pressure, the amount of unreacted polymerizable monomer was 250 ppm. Further, the yield of toner particles after discharge was 90%. Further, in order to maintain the same degree of decompression as in Example 3, a vacuum pump having a larger capacity than the vacuum pump used in Example 3 was necessary.
[0154]
The obtained toner particles were externally added with the same hydrophobic silica as used in Example 1 to obtain a developer. Further, when the same image formation evaluation as in Example 1 was performed, 2500 sheets were obtained. The solid white spots due to poor transfer occurred from about 3,000, and the image density decreased from about 3,000 sheets.
[0155]
<Comparative Example 3>
Preliminary heat treatment apparatus similar to that of Example 3 using toner particles (Tg: 62 ° C.) similar to that of Example 1 except that superheated steam having a temperature of 70 ° C. and a vapor pressure of 3 kPa is introduced into the reduced pressure heat treatment apparatus. -It processed on the same heat processing conditions using the pressure reduction heat processing apparatus.
[0156]
The toner particle product temperature at the start of the reduced pressure heat treatment was 22 ° C.
[0157]
When the toner particles were discharged after completion of drying, a lot of hard aggregation of the toner particles was observed. In addition, fusion of toner particles was observed on the inner wall surface of the apparatus. For this reason, the yield of toner particles after discharge was 80%, and the evaluation performed in Example 1 as toner particles could not be performed.
[0158]
<Example 9>
Supply flow rate of superheated steam 0.50m ^Three / Hr · kg (toner particles), the same toner particles as in Example 1 except that the degree of vacuum during processing was changed to 5 kPa, and the vapor pressure of superheated steam to be supplied was changed to 5 kPa. It processed on the same heat processing conditions using the same preliminary heat processing apparatus and pressure reduction heat processing apparatus.
[0159]
The toner particle product temperature at the start of the reduced pressure heat treatment was 22 ° C.
[0160]
At the end of the treatment, the water content was 0.3%, and the amount of unreacted polymerizable monomer was 90 ppm. The yield of toner particles after discharge was 85%.
[0161]
The obtained toner was externally added with the same hydrophobic silica as used in Example 1 to obtain a developer, and image formation evaluation was performed in the same manner as in Example 1. As a result, the environment was 30 ° C./80% RH. In the image printing below, there were some solid white spots due to poor transfer on about 9,000 sheets.
[0162]
<Example 10>
Supply flow of superheated steam is 0.01m ^Three / Hr · kg (toner particles), except that the same toner particles as in Example 1 and the same heat treatment conditions as in Example 3 using the same preliminary heat treatment apparatus and reduced pressure heat treatment apparatus as in Example 3. Processed.
[0163]
The toner particle product temperature at the start of the reduced pressure heat treatment was 22 ° C.
[0164]
At the end of the reduced pressure heat treatment, the amount of unreacted polymerizable monomer was 100 ppm. The yield of toner particles after discharge was 94%.
[0165]
The obtained toner was externally added with the same hydrophobic silica as used in Example 1 to obtain a developer, and the developer was further evaluated for image formation in the same manner as in Example 1. In image printing under an 80% RH environment, solid white spots due to poor transfer occurred slightly on about 8,000 sheets.
[0166]
<Example 11>
Preliminary heating similar to that in Example 3 except that the degree of vacuum during processing is 4.2 kPa, and saturated water vapor having a temperature of about 30 ° C. is charged into the vacuum heating apparatus. It processed on the same heat processing conditions using the processing apparatus and the pressure reduction heat processing apparatus. The toner particle product temperature at the start of the reduced pressure heat treatment was 22 ° C.
[0167]
At the end of the treatment, the water content was 0.5%, and the amount of polymerizable monomer was 95 ppm. Further, the yield of toner particles after discharge was 88%.
[0168]
The obtained toner was externally added with the same hydrophobic silica as used in Example 1 to obtain a developer, and image formation evaluation was performed in the same manner as in Example 1. As a result, 30 ° C./80% RH was obtained. In image printing under the environment, solid white spots due to poor transfer occurred slightly on about 8,500 sheets.
[0169]
Table 1 shows the reduced pressure heat treatment conditions and results performed in the examples and comparative examples. In the image output test, solid areas were blanked out, the image density was lowered, or the toner was fused to the photoconductor, and the number of copies when any of these problems occurred was evaluated according to the following criteria. .
When there is no problem even with 10,000 sheets ... A
8000 to 10000 sheets ・ ・ ・ B
From 4000 to 8000 ... C
When 2000 to 4000 sheets ・ ・ ・ D
When there are less than 2000 sheets ... E
It was.
[0170]
[Table 1]

[0171]
【The invention's effect】
According to the present invention, there is provided a method for producing toner particles in which heat treatment is performed in a short time so as not to receive heat for a long time in order to remove volatile components present in the toner particles obtained by the polymerization method. realizable.
[Brief description of the drawings]
FIG. 1 is a schematic diagram illustrating an example of a system of an apparatus that disperses toner particles in a granular form in a hot air stream and performs heat treatment while sending the toner particles in parallel with a high-speed air stream.
FIG. 2 is a schematic diagram showing an example of a system that performs a heat treatment under reduced pressure while introducing an injection medium.
FIG. 3 is a schematic diagram showing another example of a system that performs a heat treatment under reduced pressure while introducing an injection medium.
FIG. 4 is a schematic diagram showing another example of a system that performs reduced-pressure heat treatment while introducing an injection medium.
[Explanation of symbols]
1 Discharge blower
2 Hot air generator
3 Airflow dispersion part
4 Air outlet
5 Loop-type airflow heating tube
6 Raw material supply equipment
7 Cyclone
8 Outlet
9 Bag filter
10 Exhaust blower
11 Vacuum heat treatment container (ribbon blade)
12 Drive motor
13 Stirring central axis
14 Ribbon wing
15 Stirring blade support arm
16 Connecting arm
17 Raw material supply port
18 Bag filter
19 Condenser
20 jacket
21 Hot water tank
22 Pressure reducing pump
23 Partition plate
24 Filter cloth
25 Nozzle for backwashing
26 Injection medium heater
27 Separator
28 Expansion tank
29 Dispersion board
30 Injection medium nozzle
31 Injection medium thermometer
32 Injection medium temperature controller
33 Reduced pressure heat treatment equipment (screw blade)
34 Drive arm
35 Screw type stirring member
36 Injection medium flow meter

Claims (20)

A toner obtained by polymerizing a polymerizable monomer composition containing at least a polymerizable monomer and a colorant in an aqueous dispersion medium to form colored polymer particles, followed by washing and dehydration. The particles are supplied to a container that can be depressurized and heated, and an injection selected from the group consisting of saturated water vapor, superheated water vapor having a temperature lower than the glass transition temperature Tg of toner particles, and high-humidity air having an enthalpy of 2500 kJ / kg (dry air) or more. A method for producing toner particles, comprising subjecting a medium to heat treatment under reduced pressure while being charged into the container. The method for producing toner particles according to claim 1, wherein the high-humidity air has a moisture content of 50% or more. The method for producing toner particles according to claim 1, wherein the high-humidity air has a moisture content of 60% or more. 2. The method for producing toner particles according to claim 1, wherein the enthalpy of the high humidity air is 6500 kJ / kg (dry air) or more. 2. The method for producing toner particles according to claim 1, wherein high-humidity air has a moisture content of 50% or more and an enthalpy of 6500 kJ / kg (dry air) or more. 2. The method for producing toner particles according to claim 1, wherein the high humidity air has a water content of 60% or more and an enthalpy of 6500 kJ / kg (dry air) or more. 2. The method for producing toner particles according to claim 1, wherein the high humidity air has a moisture content of 80% or more and an enthalpy of 6500 kJ / kg (dry air) or more. The method for producing toner particles according to claim 1, wherein the supply flow rate of the injection medium is 0.01 to 0.5 m ³ / hr · kg (toner particles). The method for producing toner particles according to claim 1, wherein the supply flow rate of the injection medium is 0.04 to 0.27 m ³ / hr · kg (toner particles). The method for producing toner particles according to claim 1, wherein the heat treatment under reduced pressure is a step of removing volatile components in the toner particles. 10. The heat treatment under reduced pressure is a step of removing volatile components in the toner particles, and the treatment is performed until the unreacted polymerizable monomer is 100 ppm or less. Toner particle manufacturing method. The method for producing toner particles according to claim 10 or 11, wherein the volatile component contains at least an unreacted polymerizable monomer. 12. The method for producing toner particles according to claim 10, wherein the volatile component contains at least a decomposition product of the polymerization initiator. 14. The method for producing toner particles according to claim 1, wherein the water content of the toner particles supplied to the heat treatment under reduced pressure is 3.0% or less. The method for producing toner particles according to any one of claims 1 to 13, wherein the water content of the toner particles supplied to the reduced-pressure heat treatment is 1.0% or less. 16. The method for producing toner particles according to claim 1, wherein the aqueous dispersion medium is removed by performing a preliminary heat treatment before the reduced-pressure heat treatment. Preliminary heat treatment is a method in which wet colored polymer particles are dispersed in a high-speed hot air stream and simultaneously heated while being sent in parallel flow. The method for producing toner particles according to claim 16, wherein the toner particles can be supplied and processed. The preliminary heat treatment is characterized in that after the aqueous dispersion medium is removed or simultaneously with the removal, the temperature of the colored polymer particles is raised to 30 to 60 ° C. and the reduced pressure heat treatment is performed while maintaining the temperature. The method for producing toner particles according to 16. A polymerizable monomer composition containing at least a polymerizable monomer and a colorant is polymerized in an aqueous dispersion medium to form colored polymer particles, and then washed, dehydrated, and obtained color Supply polymer particles to a container that can be depressurized and heated, and heat treatment under reduced pressure while introducing either saturated steam, superheated steam, or high humidity air of enthalpy 2500 kJ / kg (dry air) or higher into the container. Detecting the temperature A of the injection medium,
The temperature A is as follows: 30 ° C. <A <Glass transition temperature Tg of toner particles
A toner particle manufacturing system, wherein the heat treatment is performed under reduced pressure so as to satisfy The system for producing toner particles according to claim 19, wherein a condenser is provided in the middle of a path for discharging volatile components generated by the reduced-pressure heat treatment, and the vapor component is collected as water.

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