JP3278326B2 - 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 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 50% by weight of particles having a weight average particle size of 20 μm or less are used.
In order to efficiently classify the powders contained above, the powders are carried in an air current and transported, and based on the Coanda effect, the difference in the inertial force, centrifugal force, etc. according to the particle size of each particle in those powders. The present invention relates to an airflow type classification device for classifying particles having a predetermined particle size and a method for producing a toner using the device.

[0002]

2. Description of the Related Art Various methods for classifying powders have been proposed. Among these, there are a classifier using a rotary wing and a classifier without a movable part. Among these, there are a fixed-wall centrifugal classifier and an inertial force classifier as classifiers without moving parts, but Lof is a classifier that uses inertial force.
fier. F. and K. Mally: Symp on
An elbow jet classifier described in Powder Techn D2 (1981) and commercialized by Nippon Steel Mining Co., Ltd., and Okuda. S. and Yasukun
i. J. Proc. linter. Symposium
on Powder Techn'81, 771 (19
81) has been proposed as an inertial force classifier capable of classifying in the fine powder region.

[0003] These air-flow classifiers are shown in Figs.
As shown in FIG. 7, powder is ejected from the supply nozzle 16 having an opening in the classification area of the classification chamber into the classification area at a high speed together with the airflow, and the powder is coarsely generated by the centrifugal force of the curved airflow flowing along the Coanda block 26 in the classification chamber. Separated into powder, medium powder and fine powder, and the edges 117 and 118 having thinner tips,
Classifying coarse, medium and fine powders.

However, in the conventional classifier 101, the finely pulverized raw material is introduced from the raw material supply nozzle 16, and the granular material flowing inside the pyramid has a tendency to flow straight and parallel to the tube wall with a propulsive force. The material supply nozzle 1
6, 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 powders, and the lower stream contains a lot of heavy coarse powders. Flows independently, so that different loci may be drawn depending on the introduction site into the classifying chamber, and coarse powder disturbs the locus of fine powder. In the classification of powder having a large amount of coarse particles, the precision tends to be remarkably reduced. Also, in general, the classification edge blocks 124 and 125 are fixed to the classifier body, adjust the tip positions of the classification edges 117 and 118, and adjust the flow rate of the air flow for classification in accordance with the classification points (ie, the classification points). (The size of the particle that is the boundary for classification) was set to a desired value. Further, the tip position of the classification edge corresponding to the specific gravity of the powder and the predetermined classification point is detected and moved, and the flow is controlled to a predetermined flow rate accordingly. As described above, simply adjusting only the tip positions of the classification edges 117 and 118 easily causes turbulence in the vicinity of the edge tip depending on the angle, and as a result, accurate classification may not be obtained. In some cases, particles of a size that should fit in another particle group may be mixed into a particle group that must be uniform in size. Also, even if it is desired to change the classification point, the position of the classification edge cannot be controlled along the airflow direction even if the tip position of the classification essi is changed and the flow rate is controlled to a predetermined flow rate accordingly. Not only it takes time to adjust the classification point to a predetermined value, but also there are problems to be improved such that the classification accuracy tends to decrease. In particular, such problems are likely to become apparent during classification for producing a toner for developing an electrostatic image used in a copying machine, a printer, and the like.

In general, since many different properties are required for a toner, to meet such demands, the properties of the toner as well as the raw materials used are often affected by the manufacturing method. In the classifying process for producing the toner, it is 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 used in a toner. A powder containing such a resin is used in a classifier. When introduced and classified, adhesion or fusion in the classification device is likely to occur.

In recent years, for example, as an energy-saving measure of a copying machine, a soft binder such as wax is used as a binder resin in order to fix the recording material by pressure. Speed up,
In order to 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.

Further, toner particles tend to be gradually miniaturized in order to improve the image quality in copying machines and printers. Generally, as the material becomes finer, the action of the interparticle force increases, but the same applies to resin particles and toner particles.

When an external force such as an impact force or a frictional force acts on such an agglomerate, particles easily fuse in the vicinity of the raw material introduction port and the high pressure air supply port in the raw material supply system shown in FIG.
In addition, it is easy to fuse in a classifier. In particular, fusing to the throat part of the raw material introduction port and the tip of the classification edge is likely to occur, and if such a phenomenon occurs, the classification accuracy is reduced, and the classification device is not operating in a stable state. Is difficult to obtain over 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.

[0011]

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 using the apparatus.

An object of the present invention is to use an air-flow type classification apparatus and a pneumatic classification apparatus capable of setting a correct classification point to enable more accurate classification and efficiently producing a powder having a fine particle size distribution. To provide a method for producing a toner.

Another object of the present invention is to provide a pneumatic classifier capable of performing stable classification with less occurrence of fusing or the like and less fluctuation of a classification point in the apparatus, and a toner using the apparatus. It is to provide a method of manufacturing the.

It is a further object of the present invention to provide an airflow classifier capable of greatly changing the classification point and a method for producing a toner using the classifier.

It is a further object of the present invention to provide an airflow classifier capable of changing the classification point in a single time and a method for producing a toner using the apparatus.

[0016]

SUMMARY OF THE INVENTION According to the present invention, a powder material supplied from a material supply nozzle at least in a classification region formed by a Coanda block and a plurality of classification edges is subjected to at least a coarse powder group by the Coanda effect. in air classifier for classifying a medium powder group and the fine powder group, the raw material supply nozzle provided on the upper surface of the air classifier, comprising a Coanda block to the side surface side of the raw material supply nozzle, The powder material is supplied to the rear end of the material supply nozzle.
And an outer wall of the powder raw material introduction pipe.
And a high-pressure air introduction section surrounding the powder material.
The present invention relates to an airflow classifier characterized by ejecting from only the tip of a material supply nozzle .

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 powder. In the method, the raw material supply nozzle installed on the upper surface of the airflow classifier is provided at the rear end with a powder raw material introduction pipe for supplying colored resin particles.
And introduction of high-pressure air surrounding the outer wall of the powder material introduction pipe.
And the high pressure air from the high pressure air introduction pipe
The colored resin particles from the powder material introduction pipe are
In the classification area formed by the Coanda block and the plurality of classification edges , which are supplied to the raw material supply nozzle and are installed on the side surface side of the raw material supply nozzle , only the tip of the raw material supply nozzle
Production of the toner and generating a toner colored resin particles to be ejected from at least the coarse powder group by the Coanda effect, and classified into a medium powder group and the fine powder group, the classified Chuko member group from About the method.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION In a pneumatic classification device of the present invention and a method of producing a toner using the device, a material supply preferably installed at an angle of θ = 45 ° or less with respect to a vertical direction. Equipped with a high-pressure air introduction unit and a powder material introduction tube at the rear end of the nozzle, and supply the material powder from a material supply port above the powder material introduction tube. The powder is radiated from the lower portion of the inlet from the inner center of the powder material inlet, is pressurized and dispersed by high-pressure air, and can be supplied from the material supply nozzle. When the shape of the classification area is changed, the classification point can be significantly changed, and the classification point can be adjusted with high accuracy without generating airflow turbulence near the front end of the classification edge.

[0019]

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.
A device of the type shown in (cross-sectional view) and FIGS. 2 and 3 is illustrated as one specific example.

1, 2 and 3, the side walls 22 and 23 form a part of the classifying chamber,
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. The installation positions of the classification edge blocks 24 and 25 can be slid up and down, and accordingly, the respective knife edge type classification edges 17 and 18 also slide up and down. The classification zones of the classification room 32 are divided into three by the classification essences 17 and 18.

A raw material supply port for introducing the raw material powder is provided at the rearmost end of the raw material supply nozzle 16, and a high pressure air supply unit 41 and a powder supply port are provided at the rear end of the raw material supply nozzle 16. A Coanda block having a material introduction pipe 42 and an opening in the classifying chamber 32 is provided on the right side of the side wall 22, and has a long elliptical arc drawn in an extending direction of a right tangent to the material supply nozzle 16. 26 are installed. The left block 27 of the classifying chamber 32 has a knife-edge type inlet edge 19 on the left 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 which open to the classifying chamber 32. is there. Further, the first and second gas introduction adjusting means 20 and 2 such as dampers are provided in the intake pipes 14 and 15.
1, a static pressure gauge 28 and a static pressure gauge 29 are provided.

Classification edges 17 and 18 and inlet edge 1
The position of 9 is adjusted according to the type of powder as the raw material to be classified and the desired particle size.

On the right side of the classifying chamber 32, the outlets 11, 1 opening into the classifying chamber corresponding to the respective dividing areas.
The outlets 11, 12 and 13 are connected to communication means such as pipes, and each of them may be provided with an opening / closing means such as a valve means.

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

The classification operation in the multi-segment classification area configured as described above is performed, for example, as follows. That is,
The pressure in the classifying chamber is reduced through at least one of the outlets 11, 12, and 13. The flow rate is preferably 50 to 300 m / h by the high-pressure air and the gas flow flowing through the raw material supply nozzle 16 having an opening in the classifying chamber. The powder is ejected into the classification chamber through the raw material supply nozzle 16 at a speed of seconds.

The particles in the powder introduced into the classifying chamber are bent by the action of the Coanda effect of the Coanda block 26 and the action of gas such as air flowing in at that time.
30b, 30c, etc., and move according to the particle size of each particle and the magnitude of the inertia force, and the large particles (coarse particles) are outside the airflow, that is, the first fraction outside the classification edge 18, the intermediate The particles are classified into a second fraction between the classification edges 18 and 17, the small particles are classified into a third fraction inside the classification edge 17, and the large classified particles are discharged from the outlet 11 and the classified intermediate particles are discharged. The particles are discharged from outlet 12,
The classified small particles are discharged from the discharge ports 13 respectively.

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.

[0029] In air classifier of the present invention, by supplying the raw material supply port or et material powder, supplied raw material powder is emitted from the inner center of the powder material inlet from the lower feed powder introducing port 40 Because it is accelerated on the high-pressure air ejected from the high-pressure air introduction part 41 and accelerated and dispersed well, it is instantaneously introduced from the raw material supply nozzle 16 into the classification room, is classified, and is discharged out of the classification machine system. The powder introduced into the classifier flies with propulsive force in a state in which the aggregated powder is dispersed to the primary particles without disturbing the trajectories of the individual particles from the raw material supply nozzle 16 by the inlet portion in the classification chamber. is important. The particle flow flowing from inside the material supply nozzle 16 is such that when the material is introduced from above, the powder flow is introduced into the classification chamber 32 having the Coanda block 26 at a position lateral to the opening of the material supply nozzle 16. The particle trajectory is dispersed according to the size of the particles without disturbing the flight trajectory of the particle, so that the classification edge is moved in the direction along the streamline, and then the edge tip position of the classification edge is fixed, It can be set to a predetermined classification point. This classification edge 17
, And 18, the classification edge blocks 24 and 2
By the simultaneous movement with 5, the direction of the edge can be made to follow the flow direction of the particle flow flying along the Coanda block 26.

Specifically, in FIG. 5, the tip of the classification edge 17 and the side surface of the Coanda block 26 are centered, for example, at a position O in the Coanda block 26 corresponding to the side surface of the tip opening 16a of the raw material supply nozzle 16. Distance L
₄ and the distance L ₁ between the side surface of the classification edge 17 and the side surface of the Coanda block 26, the classification edge block 24 is moved up and down along the positioning member 33 so that the classification edge 17 is moved up and down along the positioning member 34. It can be adjusted by moving and further turning the tip of the classification edge 17 around the shaft 17a.

[0031] Similarly, the side surface of the classifying edge 18 of the tip and the Coanda distance between the side wall of the block 26 L ₅ and classifying the distance between the side edges 17 and the side surface of the classifying edge 18 L ₂ or classifying edge 18 of the side surface and the side wall 23 distance L ₃ between, by moving the classifying edge blocks 25 up and down along the locating member 35 to move the classifying edge 18 up and down along the locating member 36, a further axis 18a of the tip of the classifying edge 18 It can be adjusted by turning around the center. That is, the Coanda block 26 and the classification edge 1 are provided on the side surface of the tip opening 16a of the raw material supply nozzle 16.
7 and 18 are installed, and classification edge block 2
With the change of the installation position of 4 or / and the classification edge block 25, the classification area of the classification room is expanded, and the classification point can be easily and significantly adjusted.

Therefore, the turbulence of the flow due to the tip of the classification edge can be prevented, and the flying speed of the particles is increased by adjusting the flow rate of the suction flow due to the reduced pressure through the discharge pipes 11a, 12a, and 13a, thereby increasing the flying speed of the particles. In addition to improving the dispersion of the powder raw material at a high concentration and obtaining a good classification accuracy even at a higher dust concentration, not only can a reduction in product yield be prevented, but also a better classification accuracy and a product yield at the same dust concentration Can be improved.

Further, the distance L ₆ between the tip of the inlet edge 19 and the wall surface of the Coanda block 26 can be adjusted by rotating the tip of the inlet edge 19 about the axis 19a. Further adjustment of the classification point is possible by adjusting the inflow rate and the inflow rate of the gas from 14 and 15.

The above-mentioned set distance is appropriately determined according to the characteristics of the powder raw material and the like.
When 1.4 g / cm ³ , L ₀ <L ₁ + L ₂ <nL ₃ (n ≧ 1: real number) When 1.4 g / cm ³ is exceeded, L ₀ <L ₃ <L ₁ + L ₂ must be satisfied. Is preferred. If this is satisfied, a product (medium powder) having a sharp distribution can be efficiently obtained.

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 a device system. A preferred example of such a device system is shown in FIG. The integrated device system shown in FIG. 6 connects a three-divider classifier 1 (the classifier shown in FIGS. 1 and 2), a fixed-quantity feeder 2, a vibration feeder 3, and collection cyclones 4, 5, and 6 by communication means. It is.

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. For introduction, 50-30
The powder is introduced into the classifier 1 at a flow rate of 0 m / sec.
The size of the classifying chamber of the classifier 1 is usually [10
~ 50cm] x [10-50cm], so the powder is 0.1
The particles can be classified into three or more kinds of particles in an instant of 1 to 0.01 seconds or less. Then, the particles are classified into large particles (coarse particles), intermediate particles, and small particles by the three-division classifier 1. afterwards,
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. 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 when classifying toner or colored resin powder for toner 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 toner composition using such a resin is subjected to a conventional classifier, a fused matter is easily generated at the particle flow pipe extending from the tip of the injection air introduction pipe to the raw material supply nozzle and at the tip of the classification edge. If a fused material is generated, it deviates from an appropriate classification point. Then,
Even if the flow rate is adjusted by suction pressure reduction, the required particle size distribution of the powder is hardly obtained, and the classification efficiency is drastically reduced. Furthermore, a fused product is mixed in the classified powder, and it is difficult to obtain a high quality product.

In the classification device of the present invention, the classification edges 17 and 18 move in the flow direction of the particle flow simultaneously with the classification edge blocks 24 and 25, and the classification edges 17 and 18 flow in the flow direction of the particle flow flying along the Coanda block 26. After following the direction, the discharge ducts 11a, 12
a, the dispersion speed of the particles in the classification region can be further improved by adjusting the flow rate of the suction flow through 13a, so that the classification yield is improved and the classification edge is improved. Has the effect of preventing or suppressing the fusion of the particles and performing highly accurate classification.

In the classifier of the present invention, the effect is more remarkable as the particle diameter of the powder is smaller.
It is possible to obtain a classified product having a sharp particle size distribution when classifying powder having a particle size of μm or less, and further to obtain a classified product having a sharp particle size distribution from a powder having a weight average diameter of 6 μm or less. It is possible.

Further, in the classification device of the present invention, a stepping motor or the like is used as a moving means for moving the classification edge direction and the edge tip position, and a potentiometer or the like is used as a detection means for detecting the edge tip position. It is more preferable to control the position of the leading edge of the classification edge by the controlling device and to further automate the flow rate control, because a desired classification point can be obtained more quickly and more accurately.

Example 1 100 parts by weight of styrene-butyl acrylate divinylbenzene copolymer (monomer weight ratio 80.0 / 19.0 / 1.0, weight average molecular weight Mw 350,000) Magnetic iron oxide (average) 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 Model 5 (Mitsui Miike Kakoki Co., Ltd.), and then kneaded with a twin-screw kneader (PCM-30, 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 with a collision type air current pulverizer to obtain a pulverized raw material having a weight average diameter of 6.7 μm, and a true density of 1.73 g / cm ³ .

35.0 kg of the obtained pulverized raw material via the feeder 2 via the vibration feeder 3 and the raw material supply pipe 16 (the powder raw material introduction pipe 42, the high-pressure air introduction section 41 and the deformed cylindrical section 43). In order to classify into three types of coarse powder, medium powder and fine powder utilizing the Coanda effect at a ratio of / h, the powder was introduced into a multi-segment classifier 1 shown in FIG.

At the time of introduction, the suction force derived from the pressure reduction in the system by the suction pressure reduction of the collection cyclones 4, 5, 6 communicating with the discharge ports 11, 12, 13 and the raw material supply nozzle 16
Compressed air from the high-pressure air introduction unit 41 attached to the device was used.

In order to change the shape of the classification area, each set distance is set to L ₀ = 6 mm (the height diameter of the material supply nozzle discharge port 16a) L ₁ = 34 mm (the side of the classification edge 17 and the Coanda block 26). L ₂ = 33 mm (the side of the classification edge 17 and the classification edge 1)
L ₃ = 37 mm (distance between the side surface of the classification edge 18 and the side surface of the side wall 23) L ₄ = 16 mm (distance between the tip of the classification edge 17 and the side surface of the Coanda block 26) L ₅ = 34 mm (Distance between the tip of the classification edge 18 and the side surface of the Coanda block 26) L ₆ = 25 mm (distance between the tip of the inlet edge 19 and the side surface of the Coanda block 26) R = 14 mm (radius of the arc of the Coanda block 26) Classification.

The introduced finely pulverized raw material was classified instantaneously in 0.1 seconds or less. The classified medium powder has a weight average particle size of 6.95 μm (22% by number of particles having a particle size of 4.0 μm or less).
1.0% by volume containing particles having a particle size of 10.08 μm or more
Medium powder having a sharp distribution of (contained) can be obtained with a classification yield (the ratio of the finally obtained medium powder to the total amount of the input pulverized raw materials) of 88%, which is excellent for toner. Had performance. The classified coarse powder was circulated again to the pulverizing step.

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

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-11 or Coulter Multisizer 1
1 (manufactured by Coulter). As an electrolyte, about 1% NaCl aqueous solution is adjusted using primary sodium chloride. For example, ISOTONR-11 (manufactured by Coulter Scientific Japan) can be used.

The measuring method is as follows.
In 150 ml, 0.1 to 5 ml of a surfactant, preferably an alkylbenzene sulfonate, is added as a dispersant, and 2 to 20 mg of a measurement sample is further added. The electrolyte in which the sample is suspended is subjected to dispersion treatment for about 1 to 3 minutes with an ultrasonic disperser,
Using the measuring device, the volume and number of the toner were measured using a 100 μ aperture as the aperture, and the volume distribution and the number distribution were calculated. Then, a weight-based weight average 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 pulverized with a collision type air current pulverizer to obtain Table 1.
The classification was performed using the same apparatus system except that the set distance of the classification region shown in Table 1 was used using the pulverized raw materials shown in Table 1. Table 2
As shown in Table 3 and Table 3, medium powder having a sharp distribution can be efficiently obtained, and excellent performance was obtained for toner.

[0053]

[Table 1]

[0054]

[Table 2]

[0055]

[Table 3]

(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 (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 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 with a collision type air current pulverizer to obtain a pulverized raw material having a weight average diameter of 6.5 μm and a true density of 1.08 g / cm ³ .

Using this milled raw material, classification was performed using the same apparatus system as in Example 1 except that the classification conditions shown in Table 4 were used.

Further, the above coarsely crushed material was finely pulverized with a collision type air current pulverizer to obtain a pulverized raw material (Example 6) having a weight average particle size of 5.5 μm, and classified under the classification conditions shown in Table 4.

As shown in Tables 5 and 6, medium powder having a sharp distribution can be efficiently obtained.
It had excellent performance for toner.

[0061]

[Table 4]

[0062]

[Table 5]

[0063]

[Table 6]

(Comparative Examples 1 to 3) Using the same toner raw material as in Example 1, a coarsely crushed product for toner production was finely pulverized by an impinging air current pulverizer to obtain a pulverized raw material having a weight average particle size of 6.9 μm. A pulverized raw material (Comparative Example 2) having a weight average particle size of 5.5 μm and Comparative Example 1) was obtained.

Further, the raw material of the toner was changed to that of Example 5 to obtain a pulverized raw material having a weight average particle diameter of 6.0 μm (Comparative Example 3).

The classification was performed according to the flowchart of FIG. 10, and the multi-division classification apparatus used was that of FIGS. 7, 8 and 9.

The classification conditions are as shown in Table 7.
Tables 8 to 1 show the particle size distribution and the like of the intermediate powder obtained by the classification.
0.

[0068]

[Table 7]

[0069]

[Table 8]

[0070]

[Table 9]

[0071]

[Table 10]

[0072]

According to the airflow classifier of the present invention, the fusion at the tip of the classification edge can be prevented well, and the turbulence of the classification airflow at the tip of the classification edge can be well prevented.
Accurate classification points can be obtained according to the specific gravity of various powders and classification airflow conditions, and the classification yield can be improved without shifting the classification points even when the apparatus is operated in conjunction. It is particularly effective when classifying toner having a weight average particle size of 10 μm or less.

[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 perspective view of an airflow classifier of the present invention.

FIG. 3 is an explanatory view of a powder material introduction port, a high-pressure air introduction section, and a powder material introduction pipe.

FIG. 4 is a sectional view taken along the line AA ′ in FIG. 1;

FIG. 5 is a diagram showing a main part of FIG. 1;

FIG. 6 is an explanatory diagram showing an example of a classification process using the present invention.

FIG. 7 is a schematic sectional view of a conventional airflow classifier.

FIG. 8 is a perspective view of a conventional airflow classifier.

FIG. 9 is a perspective view of a conventional raw material supply unit.

FIG. 10 is a 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 Inlet pipe 16 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 Upper block 28, 29 Static pressure gauge 30a, 30b , 30c Solid particle scattering direction 31 Injection air introduction pipe 32 Classification chamber 33, 34, 35, 36 Positioning member 40 Powder material introduction port 41 High-pressure air introduction section 42 Powder material introduction pipe 43 Deformation cylinder

──────────────────────────────────────────────────続 き Continuation of front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B07B 1/00-15/00

Claims (9)

(57) [Claims] 1. A powder material supplied from a material supply nozzle at least in a classification region formed by a Coanda block and a plurality of classification edges by a Coanda effect to obtain at least a coarse powder group, a medium powder group, and a fine powder. in air classifier for classifying into groups, the raw material supply nozzle provided on the upper surface of the air classifier, comprising a Coanda block to the side surface side of the raw material supply nozzle, the rear end portion of the raw material supply nozzle To supply the powder raw material to
Surrounding the powder material introduction pipe and the outer wall of the powder material introduction pipe
A high-pressure air introduction unit, and the powder material is ejected only from the tip of the material supply nozzle.
Air classifier, characterized in that that. 2. The raw material supply nozzle has a length of 4 with respect to a vertical direction.
The airflow classification device according to claim 1, wherein the airflow classification device is installed at an angle of 5 ° or less. 3. 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. 2. An airflow classifier according to item 1. 4. A classification edge blow having the classification edge.
Position of the classifier so that the shape of the classification area can be changed.
The airflow type according to any one of claims 1 to 3, wherein
Classifier. 5. The air classifier according to any one of claims 1 to 4 installation position of the classifying edge is movable. 6. As the tip of the classifying edge is rotatable, classifying edge is air classifier according to any one of claims 1 to 5 is attached et <br/> is in the classification edge blocks . 7. A method for producing a toner for electrostatic image development from a classified powder by classifying colored resin particles containing at least a binder resin and a colorant by an airflow classifier utilizing the Coanda effect. The raw material supply nozzle installed on the upper part of the airflow classifier has a powder material for supplying colored resin particles at the rear end.
High pressure air surrounding the introduction pipe and the outer wall of the powder material introduction pipe
-With the introduction section, the high pressure air introduction pipe
Resin particles from the powder material introduction tube using high pressure air
In the classification area formed by the Coanda block and a plurality of classification edges installed on the side of the raw material supply nozzle,
Colored resin particles ejected only from the tip of the raw material supply nozzle are classified into at least a coarse powder group, a medium powder group, and a fine powder group by the Coanda effect, and toner is generated from the classified medium powder group. A method for producing a toner, comprising: 8. The classifying edge block having the classifying edge is changed in its installation position so that the shape of the classifying area can be changed, and each set distance is set to L0> 0, L1> 0, L2> 0, L3> 0 (where L0 represents the inner diameter of the raw material supply nozzle discharge port, and L1 represents the side of the classification edge that separates the medium powder group and the fine powder group from the side of the Coanda block that faces the classification edge. L2 indicates the distance between the side of the classification edge that separates the medium powder group and the fine powder group and the side of the classification edge that separates the coarse powder group and the medium powder group; L3 Indicates the distance between the side surface of the classification edge that separates into the coarse powder group and the medium powder group and the side surface of the side wall facing the classification edge.) The true density of the colored resin particles is 0.3 to At 1.4 g / cm3, classify under the condition that L0 <L1 + L2 <nL3 (n ≧ 1: real number). Method for producing a toner according to Nau claim 7. 9. The classifying edge block having the classifying edge is changed in its installation position so that the shape of the classifying area can be changed, and each set distance is set to L0> 0, L1> 0, L2> 0. , L3> 0 (where L0 represents the inner diameter of the material supply nozzle discharge port, and L1 represents the side surface of the classification edge that separates the medium powder group and the fine powder group, and the side surface of the Coanda block facing this. L2 indicates the distance between the side of the classification edge to be divided into the medium powder group and the fine powder group, and the side of the classification edge to be divided into the coarse powder group and the medium powder group, L3 indicates the distance between the side surface of the classification edge that separates the coarse powder group and the medium powder group and the side surface of the side wall facing the classification edge.) The true density of the colored resin particles is 1.4 g. classification to claim 7 for under conditions where L0 <L3 <L1 + L2 when exceeding / cm3 Manufacturing method of the mounting of the toner.