JP3295794B2 - Airflow classifier and toner manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic classification for classifying toner or colored resin powder for toner formed from a binder resin used for image formation by electrophotography by utilizing the Coanda effect. The present invention relates to an apparatus and a method for manufacturing a toner using the apparatus. In particular, in order to efficiently classify a powder containing 50% by number or more of particles having a weight average particle diameter of 10 μm or less, the present invention carries a powder having strong cohesiveness in an air stream and utilizes the Coanda effect. Therefore, an air-flow type classification device and a device for efficiently classifying particles having a predetermined particle size based on a difference in inertial force, centrifugal force, and the like according to the particle size of each particle in the powder are used. To manufacture a toner for developing an electrostatic image.

[0002]

2. Description of the Related Art Various methods for classifying powder have been proposed for airflow classification. Among these, there are a classifier using a rotary wing and a classifier without a movable part. this house,
There are fixed-wall centrifugal classifiers and inertia classifiers as classifiers without moving parts, but classifiers that use inertial force are L
offier. F. and K. Maly: Sympo
n Powder Technology D2 (1981), an elbow jet classifier commercialized by Nippon Steel Mining Co., Ltd., and Okuda. S. and Yasuku
ni. J. Proc. Inter. Symposium
on Powder Techn '81, 771
(1981) has been proposed as an inertia classifier capable of classifying in the fine powder region.

As shown in FIG. 5, these air flow classifiers have a supply nozzle 1 having an opening in a classifying area of a classifier room.
The powder is spouted into the classification area together with airflow at high speed from 16,
In the classifying chamber, coarse powder, medium powder, and fine powder are separated by the centrifugal force of the curved airflow flowing along the Coanda block 126, and coarse powder, medium powder, Classifying fine powder.

In the conventional classifier 101, the finely pulverized raw material is introduced from the raw material supply nozzle 116, and the granular material flowing inside the pyramid 116 has a tendency to flow straight and parallel to the tube wall with a propulsive force. However, the raw material supply nozzle 1
In 16 when the raw material is introduced from the upper part, it is roughly divided into an upper stream and a lower stream, the upper stream contains a lot of light fine powder, and the lower stream contains a lot of heavy coarse powder,
Since each particle flows independently, it can draw different trajectories depending on the introduction site into the classifier,
Since the coarse powder disturbs the trajectory of the fine powder, there is a limit in improving the classification accuracy, and the classification of a powder having a large number of coarse particles of 20 μm or more tends to significantly lower the accuracy.

In recent years, toner particles have tended to be gradually miniaturized in order to improve image quality in copying machines and printers. On the other hand, in recent years, for example, as an energy saving measure of a copying machine, in order to fix a recording material by pressure, a soft binder such as wax is used as a binder resin, or even when heat fixing is performed. In order to increase the fixing speed, reduce the power consumption required for fixing, and perform fixing at a low temperature, binder resins having a low glass transition point or a low softening point have been used. In general, as the material becomes finer, the function of the interparticle force increases, but the same applies to resin particles and toner. Also,
Similarly, a soft resin such as wax increases the cohesion between particles.

If such a toner particle having a strong cohesive force is classified by a conventional classifier 101, sufficient dispersion cannot be obtained in the raw material supply nozzle 116, and as a result, accurate classification may not be obtained. In some cases, particles of a size that should fit in another particle group are mixed in a group of particles that should be uniform in size. In particular, there are cases where particles that should originally enter the fine powder group or the medium powder group are mixed into the coarse powder group due to insufficient dispersion of the particles.

Further, when an external force such as an impact force or a frictional force acts on such a low softening point agglomerate, particles are liable to generate a fused material in the classification device. In particular, fusion in the raw material supply nozzle 116 is likely to occur, and when such a phenomenon occurs,
Since the classification accuracy is deteriorated and the classification device is not operated in a stable state at all times, it is difficult to obtain a high-quality classified product for a long period of time.

In view of the above, there is a need for an airflow classifier capable of stably, efficiently and accurately classifying resin fine powder such as toner.

[0009]

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.

[0010] An object of the present invention is to use an airflow type classification device and a device capable of efficiently producing a powder having a fine particle size distribution by enabling accurate classification by setting an accurate classification point. To provide a method for producing a toner for developing an electrostatic image.

[0011]

SUMMARY OF THE INVENTION According to the present invention, a raw material powder supplied from a raw material supply nozzle is at least separated by a Coanda effect in a classification region formed by at least a side wall, a Coanda block and a plurality of classification edges. coarse powder group, in air classifier for classifying a medium powder group and the fine powder group, classifying edge blocks comprising the classification edges may change its position to be able to change the shape of the classifying area a air classifier, said the raw material supply nozzle
Equipped on the upper surface of the airflow classifier ,
Oite, (i) the distal end to supply a raw material powder raw material
Powder material introduction nozzle connected to the rear end of the supply nozzle
When, it is located in the axial core portion of the (ii) raw material powder introducing nozzle
And the tip is the tip of the material powder introduction nozzle.
And a high-pressure air supply nozzle located at
Coanda block to the side surface side of the front end portion of the raw material supply nozzle
And a means for generating a rectifying action in the raw material powder introduction nozzle.

Further, the present invention relates to a method for producing a toner, comprising the step of classifying a toner containing a binder resin or a colored resin powder for a toner, which is used for image formation by electrophotography. The present invention relates to a method for producing a toner, wherein the classification is performed using

That is, in the conventional air-flow classifier, when the raw material powder is supplied from the raw material supply port provided above the raw material supply nozzle, the raw material is roughly separated from the upper flow by gravity classification in the raw material supply nozzle. Divided into the lower stream, the upper stream contains a lot of light fine powder, and the lower stream tends to contain a lot of heavy coarse powder.Each particle flows independently, so it differs depending on the introduction site into the classifier. Because of the draw of the trajectory and the coarse powder disturbing the trajectory of the fine powder, there is a limit to the improvement of the classification accuracy. Although efficient and stable operation was impossible because of the
A raw material powder introduction nozzle and a high-pressure air supply nozzle are provided on the upper surface of the airflow type classification device, and the position of the classification edge block having the classification edge can be changed so that the shape of the classification region can be changed. As a result, the occurrence of these upper flows and lower flows is suppressed. For this reason, in the introduction part into a classifier more than the conventional airflow classifier,
It has become possible to reduce the disturbance of the particle trajectory and dramatically improve the classification accuracy.

[0014] In the present invention, by providing the means for causing rectification action in the raw material powder introducing nozzle, it becomes possible to reduce the turbulence in the nozzle, the raw material powder
The impact force and frictional force between the body introduction nozzle wall and the raw material powder can be reduced, and the fusion inside the classifier is less likely to occur. Classified products can be obtained for a long period of time.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in more detail with reference to the accompanying drawings.

FIG. 1 shows an example of an airflow classifier according to the present invention.
Apparatuses of the type shown in FIG. 2 (cross-sectional view), FIG. 2 (classification area three-dimensional view), and FIG.

1, 2 and 3, the side walls 22 and 23 form a part of the classifying chamber, and the classifying edge block 2
4 and 25 have classification edges 17 and 18.
The classification edges 17 and 18 are rotatable about the axes 17a and 18a, and the classification edges can be rotated to change the classification edge tip positions. Each of the classifying edge blocks 24 and 25 can be slid right and left, and accordingly, the respective knife-edge classifying 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.

Raw material supply port 40 for introducing raw material powder
At the rear end of the material supply nozzle 16, a high pressure air supply nozzle 41 and a material powder introduction nozzle 42 at the rear end of the material supply nozzle 16, and an opening in the classifying chamber 32. The nozzle 16 is provided on the right side of the side wall 22, and the Coanda block 26 is provided so as to draw a long elliptical arc in the extending direction of the lower tangent of the raw material supply nozzle 16.
The left block 27 of the classifying chamber 32 has a knife-edge type inlet edge 19 on the right side of the classifying chamber 32, and further, on the left side of the classifying chamber 32, there are provided inlet pipes 14 and 15 opening to the classifying chamber 32. It is. Also, as shown in FIG.
4 and 15 are provided with a first gas introduction adjusting means 20, a second gas introduction adjusting means 21, such as a damper, and a static pressure gauge 28 and a static pressure gauge 29.

Classification edges 17, 18 and inlet edge 19
Is adjusted according to the type and desired particle size of the toner 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 corresponding to the respective dividing areas.
2 and 13, and communication means such as a pipe is connected to the discharge ports 11, 12 and 13, and each of them may be provided with an opening / closing means such as a valve means.

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

Further, on the inner wall of the raw material powder introduction nozzle 42,
A secondary air introduction path 43 is provided for causing a rectifying action and ejecting secondary air in a curtain shape to reduce toner fusion in the nozzle.

The classification operation in the multi-division classification region configured as described above is performed, for example, as follows. That is, the pressure in the classification chamber is reduced through at least one of the outlets 11, 12, and 13, and the air flow flowing by the reduced pressure and the high-pressure air supply nozzle 41 in the raw material supply nozzle 16 having an opening in the classification chamber. Due to the ejector effect of the compressed air, the powder is jetted into the classifying chamber through the raw material supply nozzle 16 at a flow rate of preferably 10 to 350 m / sec, and dispersed.

The particles in the powder introduced into the classifying chamber move in a curved line due to the action of the Coanda effect of the Coanda block 26 and the action of the gas such as air flowing in at that time. Depending on the diameter and the magnitude of the inertial force, the larger particles (coarse particles) are outside the airflow, i.e. the first fraction outside the classification edge 18, the middle particles are the second fraction between the classification edges 18 and 17, Classification edge 1 for small particles
7, the classified large particles are discharged from the outlet 11, the classified intermediate particles are discharged from the outlet 12, and the classified small particles are discharged from the outlet 13. Is discharged.

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 portion of the Coanda block 26 where the powder jumps out into the classification chamber 32.
8 is mainly determined by the edge tip position. further,
The classification point is the suction flow rate of the classification air flow or the raw material supply nozzle 1
6 is affected by the ejection speed of the powder.

Normally, the airflow 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 apparatus system shown in FIG. 4 includes a three-division classifier 1 (classifiers shown in FIGS. 1, 2 and 3), a quantitative feeder 2, a vibration feeder 3, a collecting cyclone 4, a collecting cyclone 5, and a collecting cyclone 5. The collecting cyclones 6 are connected by communication means.

In this apparatus system, the powder is fed into the quantitative 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. For introduction, 10-3
The powder is introduced into the three-division classifier 1 at a flow rate of 50 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 instantly divided into three or more types of particles in 0.1 to 0.01 seconds or less. Can be classified. Then, the particles are classified into large particles (coarse particles), intermediate particles, and small particles by the three-division classification device 1. Thereafter, the large particles are sent to the collection cyclone 6 through the discharge conduit 11a and collected. The intermediate particles are discharged out of the system via the discharge conduit 12a and collected by the collection cyclone 5. 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 electrophotographic image forming method.

[0029]

EXAMPLE Next, using a crushed material 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 (monomer polymerization weight ratio: 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

The above materials were mixed with a Henschel mixer (FM-7).
The mixture was well mixed with a No. 5 model (manufactured by Mitsui Miike Kakoki Co., Ltd.) and then kneaded with a twin-screw kneader (PCM-30, manufactured by Ikegai Iron Works Co., Ltd.) set at a temperature of 150 ° C. 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 crushed material was finely pulverized by a collision type air current pulverizer to obtain a pulverized raw material having a weight average particle size of 6.7 μm.

Using the Coanda effect at a rate of 35.0 kg / h through the feeder 2 and the vibrating feeder 3 and the raw material supply nozzle 16, the obtained crushed raw material is used to feed the coarse powder, the medium powder, Figures 1-4 for classifying into three types of fine powder
Was introduced into the multi-segmentation classifier 1 shown in FIG.

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 collection cyclones 4, 5, and 6 communicating with the sampler, and the compressed air from the high-pressure air supply nozzle 41 attached to the raw material powder introduction nozzle 42 were used. Further, compressed air was inserted from the secondary air introduction passage for rectification of the inner wall of the raw material powder introduction nozzle.
The introduced finely pulverized raw material was classified instantaneously in 0.1 seconds or less. The classified medium powder has a weight average particle diameter of 6.9 μm (22% by number of particles having a particle diameter of 4.00 μm or less, and a particle diameter of 1%).
A medium powder having a particle size of 0.08 μm or more (containing 1.0% by volume) is obtained at a classification yield (the ratio of the medium powder finally obtained to the total amount of the input pulverized raw materials) of 93%. And had excellent performance for toner. At this time, no fusion was observed between the inner wall of the raw material powder introduction nozzle and the raw material supply nozzle.

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 measurement method, 0.1 to 5 ml of a surfactant, preferably an alkylbenzene sulfonate, is added as a dispersant to 100 to 150 ml of the aqueous electrolyte solution, and 2 to 20 mg of a measurement sample is further added.
Add. The electrolyte in which the sample was suspended
The dispersion treatment was performed for 3 minutes, and the volume distribution and the number distribution were calculated by measuring the volume and the number of the toner by using the above-mentioned measuring device using an aperture of 100 μm as the aperture.
Then, a weight-based weight average particle diameter determined from the volume distribution according to the present invention was determined.

(Examples 2 to 4) The same crushed material for toner production as in Example 1 was obtained by pulverizing with a collision type air current pulverizer.
The classification was performed using the same apparatus system as in Example 1 under the conditions shown in Table 1 except that the position of the front end of the classification edge and the set position of the classification edge block were changed using the pulverized raw materials shown in FIG.

As a result, as shown in Table 1, medium powders having a sharp distribution could be efficiently obtained in each case, and excellent performance was obtained for toner. Also, in any of the examples, no fusion of the raw material powder introduction nozzle and the inner wall of the raw material supply nozzle was observed.

[0038]

[Table 1]

(Examples 5 to 6) 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

The above materials were mixed with a Henschel mixer (Example 1).
) And then kneaded with a twin-screw kneader (same as in Example 1) set at a temperature of 100 ° C. 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 crushed material was finely pulverized by a collision type air current pulverizer to obtain a pulverized raw material (Example 5) having a weight average particle size of 6.4 μm.

The obtained pulverized raw material is supplied through the feeder 2 via the vibrating feeder 3 and the raw material supply nozzle 16 to the pulverized raw material.
In order to classify into three types of coarse powder, medium powder and fine powder using the Coanda effect at a rate of 6.0 kg / h, FIGS.
It was introduced into the multi-divider classifier 1 shown in FIG.

At the time of introduction, the outlets 11, 12, 13
A suction force derived from the inside of the system by the suction and decompression of the collection cyclones 4, 5, and 6 communicating with the nozzle and the compressed air from the high-pressure air supply nozzle 41 attached to the introduction nozzle 42 were used. Further, compressed air was inserted from the secondary air introduction passage for rectification of the inner wall of the raw material powder introduction nozzle. The classified medium powder has a weight average diameter of 5.6 μm (containing 38% by number of particles having a particle diameter of 4.00 μm or less and 0.1% by volume of particles having a particle diameter of 10.08 μm or more). The powder could be obtained at a classification yield of 76% (the ratio of the finally obtained medium powder to the total amount of the pulverized raw materials charged), and had excellent performance for toner. At this time, no fusion of the raw material powder introduction nozzle and the inner wall of the raw material supply nozzle was observed.

The ground material was classified under the same conditions and under the same system as in Example 5 except that the position of the front end of the classification edge and the set position of the classification edge block were changed (Example 6). As a result, the classified medium powder had a weight average diameter of 5.9 μm (35% by number of particles having a particle diameter of 4.00 μm or less and 0.1% by volume of particles having a particle diameter of 10.08 μm or more). Was obtained at a classification yield (ratio of the finally obtained medium powder to the total amount of the pulverized raw materials charged) of 74%, and had excellent performance for toner. .

(Comparative Example 1) Using the same toner pulverizing raw material as in Examples 1 and 2, the pulverized raw material was fed to the feeder 2, vibrating feeder 3 and raw material supply nozzle 116 at 31.0 kg / kg.
In order to classify into three types of coarse powder, medium powder and fine powder using the Coanda effect at the ratio of h, the powder was introduced into a multi-segment classifier 101 shown in FIGS.

At the time of introduction, the outlets 11, 12, 13
And the compressed air from the injection nozzle 31 attached to the material accelerating nozzle 34 was used.

The classified medium powder has a weight average diameter of 6.8 μm.
m (containing 25% by number of particles having a particle size of 4.00 μm or less,
Classification yield of a medium powder having a broad distribution of particles having a particle size of 10.08 μm or more (containing 3% by volume) (the ratio of the medium powder finally obtained to the total amount of the input pulverized raw materials) 70% was obtained. However, when the operation time exceeded 5 hours, the classification accuracy deteriorated, and the operation was stopped. When the inner wall of the material supply nozzle was observed, fusion occurred near the injection nozzle, and the particles were uniformly dispersed in the nozzle. Turned out not to be.

(Comparative Example 2) The same toner pulverizing raw material as in Examples 3 and 4 was used, and the pulverized raw material was supplied through the feeder 2, the vibration feeder 3 and the raw material supply nozzle 116 to 26.0 kg / kg.
In order to classify into three types of coarse powder, medium powder and fine powder using the Coanda effect at the ratio of h, the powder was introduced into a multi-segment classifier 101 shown in FIGS.

At the time of introduction, the outlets 11, 12, 13
And the compressed air from the injection nozzle 31 attached to the material accelerating nozzle 34 was used.

The classified medium powder has a weight average diameter of 5.6 μm.
m (containing 40% by number of particles having a particle size of 4.00 μm or less,
Classification yield of a medium powder having a broad distribution of particles having a particle size of 10.08 μm or more (containing 3% by volume) (the ratio of the medium powder finally obtained to the total amount of the input pulverized raw materials) 68%. However, when the operation time exceeded 4 hours, the classification accuracy deteriorated, and the operation was stopped. When the inner wall of the material supply nozzle was observed, fusion occurred near the injection nozzle, and the particles were uniformly dispersed in the nozzle. Turned out not to be.

(Comparative Example 3) Using the same toner pulverizing raw material as in Examples 5 to 6, this pulverized raw material was fed to the feeder 2, vibrating feeder 3 and raw material supply nozzle 116 at 26.0 kg / kg.
In order to classify into three types of coarse powder, medium powder and fine powder using the Coanda effect at the ratio of h, the powder was introduced into a multi-segment classifier 101 shown in FIGS.

At the time of introduction, the outlets 11, 12, 13
And the compressed air from the injection nozzle 31 attached to the material accelerating nozzle 34 was used.

The classified medium powder has a weight average diameter of 5.8 μm.
m (containing 40% by number of particles having a particle size of 4.00 μm or less,
Classification yield of a medium powder having a broad distribution of particles having a particle size of 10.08 μm or more (containing 3% by volume) (the ratio of the medium powder finally obtained to the total amount of the input pulverized raw materials) 67%. However, when the classification time deteriorated when the operation time exceeded 6 hours, the operation was stopped. When the inner wall of the material supply nozzle was observed, fusion occurred near the injection nozzle, and the particles were uniformly dispersed in the nozzle. Turned out not to be.

[0053]

As described above, according to the air-flow classifier and the method for producing the toner of the present invention, in recent years, the cohesive force has been increased and the melting point has been lowered, so that the fusing occurs on the inner wall of the device. Even with easy toner particles, rectifying means is provided in the device, so that turbulence in the device can be reduced, so that impact force and frictional force between the wall surface and the raw material powder can be reduced, Fusing in the classifier is suppressed. As a result, highly accurate classification can be performed in a constantly stable state.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of an airflow type classification device of the present invention.

FIG. 2 is a three-dimensional view of a classification unit of the airflow classification device of the present invention.

FIG. 3 is an enlarged view of the vicinity of a high-pressure air supply nozzle of the present invention.

FIG. 4 is an explanatory diagram showing an example of a classification process according to the present invention.

FIG. 5 is a schematic sectional view of a conventional airflow classifier.

FIG. 6 is an explanatory diagram showing an example of a conventional classification process.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1,101 Air flow classifier 2 Quantitative feeder 3 Vibration feeder 4,5,6 Collection cyclone 11,12,13 Outlet 11a, 12a, 13a Discharge conduit 14,15 Intake pipe 16,116 Raw material supply nozzle 17,18 , 117, 118 Classification edge 19 Inlet edge 20 First gas introduction adjustment means 21 Second gas introduction adjustment means 22, 23 Side wall 24, 25, 124, 125 Classification edge block 26 Coanda block 27 Left block 28, 29 Static pressure gauge 30 Classification area 31 Injection nozzle 32 Classification chamber 40 Raw material supply port 41 High pressure air supply nozzle 42 Raw material powder introduction nozzle 43 Secondary air introduction path 127 Upper block

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B07B 7/086

Claims (5)

(57) [Claims] In a classification area formed by at least a side wall, a Coanda block and a plurality of classification edges, a raw powder supplied from a raw material supply nozzle is subjected to at least a coarse powder group, a medium powder group, in air classifier for classifying the fine powder group, classifying edge blocks comprising the classification edges are air classifier of changing its position to be able to change the shape of the classifying area, the raw material supply A nozzle is provided on the top of the airflow classifier
In the raw material supply nozzle, (i) the raw material powder is supplied and the tip thereof is
Powder material introduction nozzle connected to the rear end of the supply nozzle
When, it is located in the axial core portion of the (ii) raw material powder introducing nozzle
And the tip is the tip of the material powder introduction nozzle.
And a high-pressure air supply nozzle is provided which is located, Coanda block to the side surface side of the front end portion of the raw material supply nozzle
And a means for causing a rectification action in the raw material powder introduction nozzle is provided. 2. The airflow classifier according to claim 1, wherein secondary air is inserted along the inner wall of the raw material powder introduction nozzle to rectify the inside of the raw material powder introduction nozzle. 3. The raw material supply nozzle, the raw material powder introduction nozzle, and the high pressure air supply nozzle have θ = 45 with respect to the vertical direction.
The airflow classification device according to claim 1 or 2, wherein the airflow classification device is installed at an angle of less than or equal to °. 4. A coarse powder discharge port for discharging the classified coarse powder group is provided below a fine powder discharge port for discharging the classified fine powder group. An airflow classification device according to any one of the above. 5. A method for producing a toner comprising a step of classifying toner or toner colored resin powder containing a binder resin used in the image formation by an electrophotographic method, according to any one of claims 1 to 4 A method for producing a toner, characterized in that the classification is carried out by using an air-flow classifier.