JPH1099784A - Air classifier and production of electrostatic charge image developing toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an accurate classifying point, to enable classification of high accuracy, to effectively form powder having minute particle distribution and to make it suitable for production of an electrostatic charge image developing toner. SOLUTION: An air classifier is constituted so that raw material powder is classified by Coanda effect in a classifying area 30 formed of plural classifying edges 17, 18 of a Coanda block 26. In this case, classifying edge blocks 24, 25 equipped with the classifying edges are those whose positions can be changed so that the shape of the classifying area may be changed. A raw material supply nozzle 16 is provided with a raw material powder introducing nozzle 42 for introducing raw material powder and a high pressure air supply nozzle 41 on the upstream side thereof, and between the raw material powder introducing nozzle 42 and the raw material supply nozzle 16, a conical dispersion nozzle 43 is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an airflow classifier for classifying powders utilizing the Coanda effect and a method for producing a toner using the classifier. In particular, the present invention relates to a method in which particles having a weight average
The present invention relates to an airflow classifier for efficiently classifying contained raw material powder. In particular, in order to efficiently classify the powder having a weight average particle diameter of 8 μm or less, the powder is carried in an air stream and the Coanda effect, the inertia force according to the particle diameter of each particle in the powder, The present invention relates to an airflow classifier for classifying particles having a predetermined particle size based on a difference in centrifugal force and the like, and a method for producing a toner for developing an electrostatic image.

[0002]

2. Description of the Related Art For classifying powders, various airflow classifiers and methods have been proposed. Among these, there are a classifier using a rotary wing and a classifier without a movable part. Among them, a classifier without a movable part includes a fixed wall centrifugal classifier and an inertial force classifier. As a classifier utilizing such an inertial force, Loffler. F. and K. Mal
y: Symposium on Powder Tec
hnology D-2 (1981), an elbow jet classifier commercialized by Nippon Steel Mining Co., Ltd., and Okuda. S. and Yasukuni.
J. : Proc. Inter. Symposium o
n Powder Technology '81, 7
71 (1981) has been proposed.

FIG. 8 is a sectional view of a conventional airflow classifier utilizing inertial force. The airflow classifier classifies the raw material powder supplied from the raw material supply port 40 from the raw material supply nozzle 116 through the raw material powder introduction nozzle 42 together with the high-speed airflow from the high-pressure air nozzle 41 by the multi-divider classifier 101. In addition to jetting into the region 32, an airflow that intersects with the jet flow at an angle is introduced from the inlet pipes 14 and 15 into the classification region 32,
Coarse powder, medium powder, and fine powder are separated by the centrifugal force of the curved airflow flowing along the Coanda block 126, and the coarse powder, medium powder, and fine powder are classified by the narrowed edges 117, 118.

The above-described multi-segment classifier 101 adjusts the positions of the tips of the classification edges 117 and 118 and adjusts the flow rate of the airflow for classification in accordance with the positions, so that the classification point (that is, the particle which is the boundary of the classification) is adjusted. Size) can be set. Further, it is also possible to detect and move the tip position of the classification edge according to the specific gravity of the powder and a predetermined classification point, and to control the flow rate to a predetermined value accordingly.

FIG. 9 is an enlarged view of the raw material powder introducing nozzle 42 in the airflow classifier of FIG. 8, and the raw material powder introduced from the rectangular cylindrical raw material powder introducing nozzle 42 is shown in FIG. Has a tendency to flow with a propulsion force straight and parallel along the tube wall of the raw material supply nozzle 116 also having a rectangular cylindrical shape, and is separated into an upper flow and a lower flow in the raw material supply nozzle 116 by gravity, Is likely to contain a lot of light fine powder, and it is easy to contain a lot of heavy coarse powder in the lower stream, and since each particle flows independently, it is possible to draw different trajectories depending on the introduction site into the classifier 101, The coarse powder tended to disturb the trajectory of the fine powder. As a result, accurate classification may not be obtained, and particles of a size that should fit in another particle group may be mixed into a particle group that should be uniform in size. Therefore, there is a problem to be improved such as a limit in improvement of classification accuracy. In particular, such a problem has been remarkable in classification for producing an electrostatic image toner used in a copying machine, a printer, and the like.

In general, a toner requires many different properties, and in order to obtain such required properties, the properties of the toner as well as the raw materials used are often influenced by the manufacturing method. In a classification process for producing a toner, it is required that the classified particles have a sharp particle size distribution. It is also desired to efficiently and stably produce high quality toner at low cost.

In general, a resin having a low melting point, a low softening point, and a low glass transition point is used as a binder resin for a toner. A powder containing such a resin is introduced into a classifier. Classification tends to cause adhesion or fusion in the classification device.

In recent years, for example, as a countermeasure for energy saving of a copying machine, a soft binder such as wax is used as a binder resin for fixing to a recording material by pressure, and a fixing speed even in the case of a heating type fixing is used. In order to speed up the fixing process and reduce the power consumption required for fixing and to fix at a low temperature, a binder resin having a low glass transition point or a low softening point has been used.

Furthermore, in recent years, in order to improve the image quality of a copying machine or a printer, toner particles have been gradually miniaturized. In general, as the material becomes finer, the action of the interparticle force increases, but the same applies to resin particles and toner particles.

As described above, as the toner particles become finer, the toner particles are more likely to aggregate, and when an external force such as an impact force or a frictional force is applied, the particles are more likely to be fused in the classification device. In particular, it is easy for fusion to occur at the tip of the classification edge and the wall surface of the material supply nozzle. If such a phenomenon occurs, the classification accuracy deteriorates and the classification device is not operating in a stable state at all times. For a long period of time.

In particular, in the case where a toner having a sharp particle size distribution is to be obtained from a toner raw material having a weight average diameter of 10 μm or less, the conventional apparatus causes a decrease in classification yield. Further, when trying to obtain a toner having a sharp particle size distribution from a toner raw material having a weight average diameter of 8 μm or less, it is remarkable that the classification yield is reduced particularly in a conventional apparatus.

In view of the above, there is a demand for an air flow classifier for stably and efficiently classifying fine powder, particularly resin fine powder such as toner, and a method for producing a toner for an electrostatically developed image.

In particular, there is a need for an apparatus and a method for more stably and efficiently classifying toner having a weight average particle diameter of 8 μm or less.

[0014]

SUMMARY OF THE INVENTION An object of the present invention is to provide an airflow classifier which has solved the above-mentioned problems and a method for producing a toner for developing an electrostatic image using the same.

An object of the present invention is to provide an air-flow classifier capable of classifying with higher accuracy by setting an accurate classification point and efficiently producing powder having a fine particle size distribution. is there.

Another object of the present invention is to provide an air flow classifier and a toner for developing an electrostatic image, which are less likely to cause fusing or the like and do not change the classifying point in the apparatus, and which can perform stable classification. It is to provide a manufacturing method.

It is a further object of the present invention to provide an airflow classifier having a large change in the classifying point and a method for producing a toner for developing an electrostatic image.

Still another object of the present invention is to provide an airflow classifier capable of changing the classification point in a short time and a method for producing a toner for developing an electrostatic image.

It is another object of the present invention to provide an airflow classifier capable of efficiently obtaining toner having a sharp particle size distribution from a toner raw material having a weight average particle diameter of 10 μm or less, and a method of manufacturing a toner for developing an electrostatic image. And

In particular, an object of the present invention is to provide an airflow classifier capable of efficiently obtaining a toner having a sharp particle size distribution from a toner raw material having a weight average particle size of 8 μm or less, and a method for producing a toner for developing an electrostatic image. I do.

[0021]

SUMMARY OF THE INVENTION The present invention relates to a raw material powder supplied from a raw material supply nozzle at least in a classification area of a multi-divided classifier formed by a Coanda block, a side wall block and a plurality of classification edges. Is classified into at least a coarse powder group and a fine powder group by the inertia force and the Coanda effect of the powder particles, wherein the classification edge block having the classification edge is classified by the multi-segment classifier. The position can be changed so that the shape of the region can be changed, and a material powder introduction nozzle and a high-pressure air supply nozzle for introducing material powder to the material supply nozzle are provided upstream of the material supply nozzle. And a conical dispersion nozzle for dispersing and smoothly transporting the raw material powder is provided between the raw material powder introduction nozzle and the raw material supply nozzle. On grade equipment.

Further, according to the present invention, a colored resin particle containing at least a binder resin and a colorant is classified by an airflow classifier utilizing the Coanda effect, and a toner for developing an electrostatic image is produced from the classified material. The present invention also relates to a method for producing a toner for developing an electrostatic image, wherein the raw material powder is classified by using the above-mentioned airflow classifier of the present invention.

According to the present invention, by disposing a cone-shaped dispersion nozzle between the raw material powder introduction nozzle and the raw material supply nozzle, the dispersion of the raw material powder is improved, and the turbulence in the apparatus is reduced. Since it is possible to reduce the impact force and frictional force between the device wall and the raw material powder, fusion inside the classifier is less likely to occur, and the classifier is always stable. Operates, and a high-quality classified product can be obtained for a long period of time.

[0024]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a method for producing a toner for developing an electrostatic charge image according to the present invention.

One example of the airflow classifier of the present invention is shown in FIGS. 1 is a sectional view, FIG. 2 is an assembled perspective view showing the structure of the multi-segmentation classifier 1, and FIG. 3 is an enlarged sectional view of a raw material powder introduction nozzle, a high-speed air supply nozzle, and a dispersion nozzle.

1 to 3, the side walls 22 and 23 form a part of the classification chamber 32, and the classification edge blocks 24 and 25 have the classification edges 17 and 18. The classification edges 17 and 18 are rotatable about the shafts 17a and 18a, and the classification edges can be rotated to change the positions of the classification edge tips. Each classification edge block 2
4 and 25 can slide the installation position right and left, and accordingly, the respective knife-shaped classification edges 17 and 18 also slide right and left. By the classification edges 17 and 18, the classification zone of the classification chamber 32 is divided into three.

A raw material supply port 40 for introducing a raw material powder is provided at the rearmost end of the raw material powder introduction nozzle 42, and a high-pressure air supply nozzle 41 is provided inside the powder introduction nozzle 42.
And a dispersion nozzle 43 between the powder introduction nozzle 42 and the raw material supply nozzle 16.

The raw material supply nozzle 16 having an opening in the classifying chamber 32 is provided on the right side of the side wall 22. The raw material supply nozzle 16 draws an elliptical arc in an extending direction of a right tangent to the raw material supply nozzle 16. A block 26 is provided. The left block 27 of the classifying chamber 32 has a knife-edge-type inlet edge 19 on the right side, which can be rotated about a shaft 19a to change the tip position of the inlet edge. Can be. Further, on the left side of the classifying chamber 32, there are provided air inlet pipes 14 and 15 which open to the classifying chamber 32.

As shown in FIG. 4, first and second gas introduction adjusting means 20, 21 such as dampers, and static pressure gauges 28, 2
9 are provided.

Classification edges 17, 18 and inlet edge 19
Is adjusted according to the type and desired particle size of the powder as the raw material to be classified.

On the upper surface of the classifying chamber 32, the outlets 11 and 1 opening into the classifying chamber correspond to the respective classification areas.
The outlets 11, 12 and 13 are connected to communication means such as pipes, and may be provided with opening and closing means such as valve means.

The cone-shaped dispersion nozzle 43 provided between the raw material powder introduction nozzle 42 and the raw material supply nozzle 16 has a conical portion or a multi-portion connected to the raw material powder introduction nozzle 42 as shown in FIG. It comprises a pyramid-shaped part and a pyramid-shaped part connected to the raw material supply nozzle 16. The maximum inclination angle of the cone-shaped dispersion nozzle 43 is preferably 45 degrees or less with respect to the vertical direction, and when set to 30 degrees or less, the raw material powder can be transported with good dispersion, and a product can be obtained with high accuracy. In addition, the generation of fused material on the apparatus wall can be reduced.

The material supply nozzle 16 comprises a right-angled cylinder and a pyramid-shaped cylinder. The ratio of the inner diameter of the right-angled cylinder to the innermost diameter of the narrowest part of the pyramid-shaped cylinder is 20: 1 to 1: 1, preferably 10: 1.
If the ratio is set to 2: 1 from, a good introduction speed can be obtained.

A run-in pipe 44 as shown in FIG. 5 may be provided between the dispersion nozzle 43 and the raw material supply nozzle 16, so that the flow rate of the raw material powder is adjusted and a product can be obtained more accurately.

The shape and the installation method may be determined according to the properties of the powder to be treated, and are not limited to the above-described shape and the installation method. For example, the configuration may be as shown in FIGS. FIG. 6 is a cross-sectional view of an airflow classifier, and FIG. 7 is an enlarged cross-sectional view of a raw material powder introduction nozzle, a high-speed air supply nozzle, and a dispersion nozzle.

In the conventional airflow classifier, when the raw material powder is supplied from the raw material supply port provided above the raw material supply nozzle, the upper flow and the lower flow are roughly performed in the raw material supply nozzle by gravity classification. The upper stream contains a lot of light fine powder, while the lower stream tends to contain a lot of heavy coarse powder, and each particle flows independently. Due to the trajectory drawing and coarse powder disturbing the trajectory of fine powder, there is a limit to the improvement of classification accuracy, and in recent years, due to the improvement of image quality and energy saving, with the toner raw material of high cohesion and low softening point However, in the present invention, the raw material powder introduction nozzle 42
By providing a cone-shaped dispersion nozzle 43 between the feed nozzle 16 and the raw material supply nozzle 16, the generation of these upper flows and lower flows is suppressed. In addition, since the position of the classification edge block having the classification edge can be changed so that the shape of the classification area can be changed, the disturbance of the particle trajectory at the introduction site into the classification device is smaller than that of the conventional classification device. And the classification accuracy can be dramatically improved.

As means for introducing the raw material powder into the classifying chamber 32 together with the airflow, a method of applying a pressure of 0.1 to 3 kg / cm ² and feeding the same, a blower located downstream of the classifying chamber is enlarged, and the classifying area is increased. A method of naturally aspirating the outside air and the raw material powder by increasing the negative pressure of the raw material, or installing an injection feeder at the raw material powder input port, thereby sucking the raw material powder and the outside air and connecting the supply pipe. And then send it to the classification room. In the present invention, it is preferable in terms of the apparatus and operation to employ a method in which the negative pressure in the classifying chamber is increased and the outside air and the raw material powder are naturally sucked and a method using an injection feeder are employed.

The multi-segment classifier 1 configured as described above
Is performed, for example, as follows. That is,
The pressure inside the classifying chamber 32 is reduced through at least one of the discharge ports 11, 12, and 13, and the airflow flowing through the raw material supply nozzle 16 having an opening in the classifying chamber and the high-pressure air supply nozzle 41 is jetted from the high-pressure air supply nozzle 41. Preferably, the flow velocity is 10 m / sec to 350 m due to the ejector effect of compressed air.
The powder is jetted into the classifying chamber 32 through the raw material supply nozzle 16 at a speed of / sec and dispersed.

The particles in the powder introduced into the classification chamber 32
The curved line 3 is formed by the Coanda effect by the action of the Coanda block 26 and the action of gas such as air flowing in at that time.
0a to 30c, and the large particles (coarse particles) are located outside the airflow, that is, the first fraction below the classification edge 18 and the intermediate particles, depending on the particle size and the magnitude of the inertial force, respectively. (Particles within the standard particle size) are divided into a second fraction between the classification edges 17 and 18, small particles (particles smaller than the standard particle size) are divided into a third fraction above the classification edge 17, and large particles are From the outlet 11, the intermediate particles are discharged from the outlet 12, and the small particles are discharged from the outlet 13.

In the classification of the powder according to the present embodiment, the classification points are the classification edges 17 and 1 with respect to the lower end of the Coanda block 26 where the powder jumps into the classification chamber 32.
8 is mainly determined by the edge tip position. Further, the classification point is affected by the flow rate of the classification airflow, the ejection speed of the powder from the raw material supply nozzle 16, and the like.

Normally, the air-flow type classification device of the present invention is used by connecting mutual devices by a communication means such as a pipe, and is incorporated in the device system. A preferred example of such a device system is shown in FIG. The integrated device system shown in FIG.
A three-divider / classifier 1 (shown in FIGS. 1 and 2; details are as described above), a quantitative feeder 2, a vibration feeder 3, a collecting cyclone 4, a collecting cyclone 5, and a collecting cyclone. 6 are connected by communication means.

In this apparatus system, the powder is fed into the fixed quantity feeder 2 by an appropriate means, and then introduced into the three-division classifier 1 through the vibrating feeder 3 by the raw material supply nozzle 16. At the time of introduction, the powder is introduced into the three-stage classifier 1 at a flow rate of 10 m / sec to 350 m / sec. Since the size of the classifying chamber of the three-segment classifier 1 is usually [10 to 50 cm] × [10 to 50 cm], the powder is instantaneously divided into three or more types of particles in 0.1 to 0.01 seconds or less. Can be classified. Then, by the three-division classifier 1, large particles (coarse particles), intermediate particles (particles having a specified particle diameter),
The particles are classified into small particles (particles having a specified particle size or less). Thereafter, the large particles are sent to the collection cyclone 6 via the discharge conduit 1la and collected. The intermediate particles are in the discharge conduit 12
The liquid is discharged out of the system via a, collected by the collection cyclone 5, and collected as a product. The small particles are discharged out of the system via the discharge conduit 13a and collected by the collection cyclone 4. The collection cyclones 4, 5, and 6 can also function as suction pressure reducing means for sucking and introducing the powder into the classification chamber via the raw material supply nozzle 16.

The airflow classifier of the present invention is particularly effective for classifying toner or toner colored resin powder used in an image forming method by electrophotography. It is particularly effective when classifying a toner composition comprising a binder resin having a low melting point, a low softening point, and a low glass transition point.

When the raw material powder is classified using the airflow classifier and the method for producing a toner for developing an electrostatic image, a toner having a sharp particle size distribution can be obtained from a toner raw material having a weight average particle diameter of 10 μm or less. And classification can be performed more efficiently than in the past. In particular, a toner having a sharp particle size distribution can be obtained from a toner raw material having a weight average particle size of 8 μm or less.

[0045]

EXAMPLE Next, actually using a pulverized product for toner production,
A specific example in which a product (toner) is obtained by performing fine pulverization and classification will be described.

Example 1 100 parts by weight of styrene-butyl acrylate-divinylbenzene copolymer (weight ratio of monomer polymerization: 80.0 / 19.0 / 1.0, weight average molecular weight Mw: 350,000) Magnetic iron oxide ( (Average particle size 0.18 μm) 100 parts by weight ・ Nigrosine 2 parts by weight ・ Low molecular weight ethylene-propylene copolymer 4 parts by weight

After the above-mentioned ingredients were mixed well with a Henschel mixer (Model FM-75, manufactured by Mitsui Miike Kakoki Co., Ltd.), a twin-screw kneader (PCM-75) set at a temperature of 150 ° C.
(Type 30; Ikegai Iron Works Co., Ltd.). The obtained kneaded material was cooled and coarsely pulverized with a hammer mill to 1 mm or less to obtain a coarsely crushed material for toner production. The coarsely pulverized product was finely pulverized by a collision type air current pulverizer to obtain a raw material powder having a weight average particle size of 6.8 μm.

The obtained raw material powder was weighed at 35.0 kg /
In order to classify into coarse powder, medium powder and fine powder using the Coanda effect at the ratio of h, the airflow classification shown in FIG. 1 is performed via the feeder 2 and the vibration feeder 3 (see FIG. 4). Introduced into the device.

At the time of introduction, the outlets 11, 12, 13
A suction force derived from the pressure reduction in the system by the suction pressure reduction of the collecting cyclones 4, 5 and 6 communicating with the sampler and the compressed air from the high pressure air nozzle 41 attached to the raw material powder introduction nozzle 42 were used. The inclination angle of the dispersion nozzle 43 is 8 °.
And

The introduced raw material powder was classified instantaneously in 0.1 seconds or less. The classified medium powder has a weight average particle size of 6.
It has a sharp distribution of 8 μm (containing 23% by number of particles having a particle diameter of 4.0 μm or less and 1.2% by volume of particles having a particle diameter of 10.08 μm or more), and has excellent performance as a toner. Had.

The particle size distribution of the toner can be measured by various methods. In the present invention, the measurement was performed using the following measuring apparatus.

That is, as a measuring device, Coulter Counter TA-II type or Coulter Multisizer I
I (manufactured by Coulter) was used. As an electrolytic solution, an approximately 1% NaCl aqueous solution is prepared using primary sodium chloride. For example, ISOTON R-II (manufactured by Coulter Scientific Japan) can be used. As a measuring method, 0.1 to 5 ml of a surfactant, preferably an alkylbenzenesulfonate, is added as a dispersant to 100 to 150 ml of the electrolytic aqueous solution, and a measurement sample is added to 2 to 20 ml.
Add mg. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment for about 1 to 3 minutes by an ultrasonic disperser, and the volume and the number of the toner are measured by using the measuring device using an aperture of 100 μm as a weight. The reference coarse powder amount (20.2 μm or more) and the number-based fine powder number (6.35 μm or less) determined from the number distribution were determined.

The true density of the finely pulverized toner was measured using the following measuring apparatus in the present invention. That is, as a measuring device, Micrometrics Acupic 1330 is used.
(Shimadzu Corporation), 5 mg of finely pulverized toner powder was measured to determine the true density.

At this time, the ratio of the finally obtained medium powder to the total amount of the input raw material powder (that is, the classification yield)
Was 91%. The classified coarse powder was circulated again to the pulverizing step. At this time, no fused material was generated on the wall surfaces of the dispersion nozzle and the raw material supply nozzle.

[Examples 2] to [Example 4] The same coarsely crushed material for toner production as in Example 1 was pulverized by a collision type air current pulverizer to obtain raw material powders shown in Table 1. The obtained raw material powder was introduced into the same apparatus system as in Example 1 except that the shape of the raw material supply port and the maximum inclination angle of the dispersion nozzle were changed as shown in Table 1, and classification was performed. Medium powder of a toner having a sharp distribution could be efficiently obtained, and the toner had excellent performance. The classified coarse powder was circulated again to the pulverizing step. At this time, no fused matter was generated on the wall surfaces of the dispersion nozzle and the raw material supply nozzle.

Example 5 100 parts by weight of unsaturated polyester resin 4.5 parts by weight of copper phthalocyanine pigment (CI Pigment Blue 15) 4.0 parts by weight of charge control agent

After the above-mentioned ingredients were mixed well with a Henschel mixer (Model FM-75, manufactured by Mitsui Miike Kakoki Co., Ltd.), a twin-screw kneader (PCM-75) was set at a temperature of 100 ° C.
(Type 30; Ikegai Iron Works Co., Ltd.). The obtained kneaded material was cooled and coarsely pulverized with a hammer mill to 1 mm or less to obtain a coarsely crushed material for toner production. The obtained pulverized raw material is finely pulverized by a collision type air current pulverizer, and has a weight average particle size of 6.1 μm.
Was obtained, and the true density was 1.08 g / cm ³ .

The resulting raw material powder was weighed at 27.0 kg /
In order to classify into coarse powder, medium powder and fine powder using the Coanda effect at the ratio of h, the airflow classification shown in FIG. 1 is performed via the feeder 2 and the vibration feeder 3 (see FIG. 4). Introduced into the device.

At the time of introduction, the outlets 11, 12, 13
A suction force derived from the pressure reduction in the system by the suction pressure reduction of the collecting cyclones 4, 5 and 6 communicating with the sampler and the compressed air from the high pressure air nozzle 41 attached to the raw material powder introduction nozzle 42 were used. Further, the inclination angle of the dispersion nozzle 43 is 10
°.

The introduced raw material powder was classified instantaneously in 0.1 seconds or less. The classified medium powder has a weight average particle size of 5.
It has a sharp distribution of 9 μm (containing 26% by number of particles having a particle diameter of 4.0 μm or less and 0.5% by volume of particles having a particle diameter of 10.08 μm or more), and has excellent performance for toner. Had.

At this time, the ratio of the finally obtained medium powder to the total amount of the input raw material powder (that is, the classification yield)
Was 78%. The classified coarse powder was circulated again to the pulverizing step. At this time, no fused material was generated on the wall surfaces of the dispersion nozzle and the raw material supply nozzle.

Example 6 to Example 7 The same crushed material for toner production as in Example 5 was pulverized by a collision type air current pulverizer to obtain raw material powders shown in Table 1. The obtained raw material powder was introduced into the same apparatus system as in Example 5 except that the shape of the raw material supply port and the maximum inclination angle of the dispersion nozzle were changed as shown in Table 1, and classification was performed. Medium powder of a toner having a sharp distribution could be efficiently obtained, and the toner had excellent performance. The classified coarse powder was circulated again to the pulverizing step. At this time, no fused matter was generated on the wall surfaces of the dispersion nozzle and the raw material supply nozzle.

Comparative Example 1 The same raw material powder as in Example 1 was classified at a rate of 30.0 kg / h into three types of coarse powder, medium powder and fine powder by utilizing the Coanda effect. 8 through a feeder 2 and a vibration feeder 3 (see FIG. 10).
Was introduced into the airflow type classification device shown in (1).

At the time of introduction, the outlets 11, 12, 13
A suction force derived from the pressure reduction in the system by the suction pressure reduction of the collecting cyclones 4, 5 and 6 communicating with the sampler and the compressed air from the high pressure air nozzle 41 attached to the raw material powder introduction nozzle 42 were used.

As a result, the weight average particle size was 6.8 μm (29% by number of particles having a particle size of 4.0 μm or less were contained, and the particle size was 10.3 μm.
(Containing 2.4% by volume of particles having a particle size of 08 μm or more) was obtained with a classification yield of 75%. The classified coarse powder was circulated again to the pulverizing step.

In this comparative example, the classification yield was inferior to that in Example 1, and a fusion product was generated on the wall surface of the raw material supply nozzle, and a fusion product was also generated near the raw material powder introduction nozzle.

Comparative Example 2 The same raw material powder as in Example 4 was classified using the same apparatus system as in Comparative Example 1.
As a result, a medium powder of the toner having a sharp distribution was obtained. The classified coarse powder was circulated again to the pulverizing step.

In this comparative example, the classification yield was inferior to that in Example 4. Further, a fusion product was generated on the wall surface of the raw material supply nozzle, and a fusion product was also generated near the raw material powder introduction nozzle.

Comparative Example 3 The same raw material powder as in Example 5 was classified using the same apparatus system as in Comparative Example 1.
As a result, a medium powder of the toner having a sharp distribution was obtained. The classified coarse powder was circulated again to the pulverizing step.

In this comparative example, the classification yield was inferior to that in Example 5, and a fusion product was generated on the wall surface of the raw material supply nozzle, and a fusion product was also generated near the raw material powder introduction nozzle.

[0071]

[Table 1]

[0072]

[Table 2]

[0073]

According to the airflow classifier of the present invention and the method for producing a toner for developing an electrostatic charge image using the device, turbulence in the device can be reduced, and the wall of the device and the raw material powder can be reduced. Advantages that can reduce the impact force and frictional force during the process, prevent fusion in the classification device, prevent device-like abrasion due to toner components, enable continuous and stable production, and enable high-precision classification. There is. Further, compared to the conventional apparatus, an electrostatic image developing toner having a stable and high image density, excellent durability and excellent predetermined particle size without image defects such as fogging and cleaning failure can be obtained at low cost. Can be In particular, it is possible to efficiently obtain a toner having a sharp particle size distribution from a toner raw material having a weight average particle diameter of 10 μm or less.
It is possible to efficiently obtain a toner having a sharp particle size distribution from a toner raw material having a weight average particle size of 8 μm or less.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of an airflow classifier according to one embodiment of the present invention.

FIG. 2 shows a multi-segment classifier 1 in the airflow classifier of FIG.
FIG. 3 is an exploded perspective view showing the configuration of FIG.

FIG. 3 is an enlarged cross-sectional view of a high-pressure air supply nozzle, a raw material powder introduction nozzle, and a dispersion nozzle in the airflow classifier of FIG.

FIG. 4 is a configuration diagram of a classification system using the airflow type classification device of FIG. 1;

FIG. 5 is a schematic sectional view of an airflow classifier according to another embodiment of the present invention.

FIG. 6 is a schematic sectional view of an airflow classifier according to another embodiment of the present invention.

FIG. 7 is an enlarged sectional view of a high-pressure air supply nozzle, a raw material powder introduction nozzle, and a dispersion nozzle in the airflow type classification device of FIG.

FIG. 8 is a cross-sectional view of a conventional airflow classifier.

FIG. 9 is an enlarged sectional view of a high-pressure air supply nozzle and a raw material powder introduction nozzle in a conventional airflow classifier.

FIG. 10 is a configuration diagram of a conventional classification system using the airflow classifier of FIG. 8;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1,101 Multi-segmentation classifier 2 Quantitative feeder 3 Vibration feeder 4,5,6 Collection cyclone 11,12,13 Outlet 1la, 12a, 13a Discharge conduit 14,15 Intake pipe 16,116 Raw material supply nozzle 17,18 , 117, 118 Classification edge 17a, 18a Classification edge axis 19 Inlet edge 19a Inlet edge axis 20 First gas introduction adjusting means 21 Second gas introduction adjusting means 22, 23 Side wall 24, 25, 124, 125 Classification edge Blocks 26, 126 Coanda blocks 27, 127 Left block 28, 29 Static pressure gauge 30 Classification area 30a Scattering trajectory of coarse powder particles 30b Scattering trajectory of medium powder particles 30c Scattering trajectory of fine powder particles 32 Classification chamber 41 High-pressure air supply nozzle 42 Raw material Powder introduction nozzle 43 Dispersion nozzle 44 Approach tube

Claims (18)

[Claims] 1. A raw material powder supplied from a raw material supply nozzle at least in a classification area of a multi-segment classifier formed by a Coanda block, a side wall block, and a plurality of classification edges. In an airflow classifier for classifying at least a coarse powder group and a fine powder group by an effect, the classification edge block having the classification edge is positioned so that the shape of the classification area of the multi-segment classification machine can be changed. Upstream of the material supply nozzle, a material powder introduction nozzle and a high-pressure air supply nozzle for introducing the material powder into the material supply nozzle, and the material powder introduction nozzle And a conical dispersion nozzle for dispersing and transporting the raw material powder between the raw material supply nozzle and the raw material supply nozzle. 2. The airflow classifier according to claim 1, wherein a maximum inclination angle of the cone-shaped dispersion nozzle is 45 degrees or less with respect to a central axis of the cone. 3. The airflow classifier according to claim 1, wherein the maximum inclination angle of the cone-shaped dispersion nozzle is 30 degrees or less with respect to the central axis of the cone. 4. The airflow classifier according to claim 1, wherein an upstream side of the cone-shaped dispersion nozzle has a conical shape. 5. The airflow classification device according to claim 1, wherein the raw material powder introduction nozzle has a cone shape. 6. The raw material supply nozzle, the raw material powder supply nozzle and the high-pressure air supply nozzle are arranged at 45 ° with respect to the vertical direction.
The airflow classification device according to any one of claims 1 to 5, wherein the airflow classification device is installed at an angle of less than or equal to °. 7. A coarse powder discharge port for discharging a classified coarse powder group is provided below a fine powder discharge port for discharging a classified fine powder group. An airflow classifier according to any one of claims 1 to 6. 8. An upstream end of the cone-shaped dispersion nozzle,
The airflow classification device according to any one of claims 1 to 7, wherein the high-pressure air supply nozzle is provided. 9. The high-pressure air supply nozzle is installed substantially at the center of the upstream end of the cone-shaped dispersion nozzle, and between the outer wall of the high-pressure air supply nozzle and the inner wall of the raw material powder introduction nozzle. The airflow classifier according to any one of claims 1 to 8, further comprising an inlet for introducing the raw material powder. 10. A method for producing a toner for developing an electrostatic image from the classified material by classifying colored resin particles containing at least a binder resin and a colorant with an airflow classifier utilizing the Coanda effect. At least in the classifying area of the multi-segment classifier formed by the Coanda block, the side wall block and the plurality of classifying edges, the raw material powder supplied from the raw material supply nozzle is subjected to at least coarse powder by the inertia force of the powder particles and the Coanda effect. An airflow classifier for classifying into a body group and a fine powder group, wherein a classifying edge block having the classifying edge has its position changed so that the shape of a classifying area of the multi-divided classifier can be changed. An upstream side of the raw material supply nozzle is provided with a raw material powder introduction nozzle and a high pressure air supply nozzle for introducing a raw material powder into the raw material supply nozzle, In addition, the raw material powder is classified using an airflow classifier provided with a conical dispersion nozzle for dispersing and transporting the raw material powder between the raw material powder introduction nozzle and the raw material supply nozzle. A method for producing an electrostatic image developing toner. 11. The electrostatic charge image developing toner according to claim 10, wherein a maximum inclination angle of the cone-shaped dispersion nozzle is 45 degrees or less with respect to a center axis of the cone. Production method. 12. The electrostatic image developing toner according to claim 10, wherein a maximum inclination angle of the cone-shaped dispersion nozzle is 30 degrees or less with respect to a center axis of the cone. Production method. 13. An upstream side of the cone-shaped dispersion nozzle,
The method for producing a toner for developing an electrostatic image according to claim 10, wherein the toner has a conical shape. 14. The method for producing a toner for developing an electrostatic image according to claim 10, wherein the raw material powder introducing nozzle has a cone shape. 15. The material supply nozzle according to claim 10, wherein the material powder supply nozzle and the high-pressure air supply nozzle are installed at an angle of 45 ° or less with respect to a vertical direction. A method for producing a toner for developing an electrostatic image according to any one of claims 1 to 3. 16. A coarse powder discharge port for discharging a classified coarse powder group is provided below a fine powder discharge port for discharging a classified fine powder group. A method for producing the electrostatic image developing toner according to claim 10. 17. The electrostatic image developing toner according to claim 10, wherein the high-pressure air supply nozzle is provided at an upstream end of the cone-shaped dispersion nozzle. Manufacturing method. 18. The high-pressure air supply nozzle is installed substantially at the center of the upstream end of the cone-shaped dispersion nozzle, and between the outer wall of the high-pressure air supply nozzle and the inner wall of the raw material powder introduction nozzle. The method for producing a toner for developing an electrostatic image according to any one of claims 10 to 17, further comprising an inlet for introducing a raw material powder.