JPH0938581A - Air current type classifier and preparation of toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable high precision classification by installing a raw material supply nozzle in an upper surface part of an air current type classifier and a Coanda block on the side of the side surface of the raw material supply nozzle in an apparatus for classifying a powder raw material supplied from the raw material supply nozzle into a coarse powder group, an intermediate powder group, and a fine powder group. SOLUTION: In classification, pressure in a classification output 32 is reduced. Particles in powder introduced into a classification chamber 32 through a raw material supply nozzle 16 are classified by a Coanda block 26. In this process, a raw material powder supplied from a raw material supply port 40 is discharged from a powder raw material introduction port 42 to be dispersed by being accelerated by high pressure air ejected from a high pressure air introduction part 41. The powder is introduced from the nozzle 16 into the classification chamber 32 to be dispersed corresponding to the size of the particles to form a particle flow. Accordingly, classification edges 17, 18 are moved along the flow line, and the edge end positions are fixed to be set up at specified classification points.

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
In order to efficiently classify the powders contained above, the powders are carried in an air stream and based on the Coanda effect, the inertial force according to the particle size of each particle in these powders, the centrifugal force, etc. 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 An air flow type classifying apparatus of various methods for classifying powder has been proposed. Among them, there are classifiers that use rotary blades and classifiers that have no moving parts. Among them, there are a fixed wall centrifugal classifier and an inertial force classifier as classifiers having no moving parts, but Lof as a classifier utilizing inertial force.
fier. F. and K. Maly: Symp on
An elbow jet classifier described in Powder Techn D2 (1981) and commercialized by Nippon Steel Mining Co., Ltd., Okuda. S. and Yasukun
i. J. Proc. inter. Symposium
on Powder Techn'81, 771 (19
The classifier exemplified in 81) is proposed as an inertial force classifier capable of classifying in the fine powder region.

These air flow type classifiers are shown in FIGS.
As shown in, the powder is jetted into the classifying area at high speed from the supply nozzle 16 having an opening in the classifying area of the classifying chamber, and is coarsened by the centrifugal force of the curved airflow flowing along the Coanda block 26 in the classifying chamber. Separated into powder, medium powder, and fine powder, and the thinned edges 117 and 118
Coarse powder, medium powder, and fine powder are classified.

However, in the conventional classifying device 101, the finely pulverized raw material is introduced from the raw material supply nozzle 16 and the powder or granular material flowing inside the pyramidal cylinder tends to flow straight in parallel with the tube wall with a propulsive force. The raw material supply nozzle 1
When the raw material is introduced from above in 6, the raw material is roughly divided into an upper flow and a lower flow, and the upper flow contains a large amount of light fine powder, and the lower flow contains a large amount of heavy coarse powder. Flow independently, so different trajectories are drawn depending on the site of introduction into the classification chamber, and coarse powder disturbs the fine powder trajectories, which limits the improvement of classification accuracy. The accuracy tended to be remarkably reduced in the classification of powders having many coarse particles. Further, generally, the classification edge blocks 124 and 125 are fixed to the main body of the classifier, and by adjusting the tip positions of the classification edges 117 and 118 and adjusting the flow rate of the airflow for classification accordingly, the classification points (ie, The size of the particles used as the boundary of 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 rate is controlled to a predetermined flow rate accordingly. As described above, if only the tip positions of the classification edges 117 and 118 are adjusted, the turbulence of the air flow easily occurs near the tip ends of the edges depending on the angle, and as a result, accurate classification may not be obtained. In this case, particles having a size that should be uniform may be mixed with particles having a size that should enter another particle group. Also, even if you want to change the classification point, it is not possible to control the position of the classification edge along the airflow direction even if the tip position of the classification essie is changed and the flow rate is controlled accordingly. There is a problem that not only it takes time to adjust the classification point to a predetermined value, but also the classification accuracy is apt to be reduced. In particular, in the classification for producing the toner for developing an electrostatic charge image used in a copying machine, a printer, etc., such a problem was likely to become apparent.

In general, toners are required to have many different properties, and in order to meet such requirements, the characteristics of the toners are often influenced by the manufacturing method as well as the raw materials used. In the classification process for producing toner, it is also desired to efficiently and stably produce high-quality toner at low cost.

Generally, as the binder resin used in the toner, a resin having a low melting point, a low softening point and a low glass transition point is used, and a powder containing such a resin is used in a classifier. When introduced and classified, adhesion or fusion is likely to occur in the classifier.

In recent years, for example, as a measure for energy saving of a copying machine, a soft resin such as wax is used as a binder resin for fixing to a recording material by pressure, or fixing is performed even in the case of heat fixing. Speed up,
Binder resins having a low glass transition point or a low softening point have come to be used for fixing at low temperature with low power consumption required for fixing.

Further, in order to improve the image quality in copying machines and printers, the toner particles tend to be gradually miniaturized. In general, as the substance becomes finer, the action of interparticle force increases, but the same applies to resin particles and toner particles, and when the size is small, the cohesiveness between particles increases.

When an external force such as an impact force or a frictional force acts on such an agglomerate, in the raw material supply system shown in FIG. 9, the particles are easily fused near the raw material introduction port and the high pressure air supply port,
Further, it is easy to fuse even in the classifying device. In particular, fusion is likely to occur at the throat portion of the raw material introduction port and the tip of the classification edge, and if such a phenomenon occurs, the classification accuracy will decrease, and the classification device will not operate in a stable state. Is difficult to obtain over the long term.

In view of the above points, there is a demand for an air flow type classifying apparatus which can classify resin fine powder such as toner in a stable, efficient and accurate manner.

[0011]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an airflow type classification apparatus which solves the above 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 device and a device therefor, which can perform more accurate classification by setting an accurate classification point and can efficiently generate 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 an air classifier capable of stable classification in which fusing and the like are less likely to occur and a classification point in the apparatus is less likely to change, and a toner utilizing the apparatus. It is to provide a method of manufacturing.

It is a further object of the present invention to provide an air flow type classification device which can change the classification point to a large extent and a method for producing toner using the device.

Another object of the present invention is to provide an airflow type classification device which can change the classification point in a single time and a method for producing a toner using the device.

[0016]

According to the present invention, a powder raw material supplied from a raw material supply nozzle is provided at least in a coarse powder group by a Coanda effect in a classification area formed by at least a Coanda block and a plurality of classification edges. In an airflow classifier for classifying into a medium powder group and a fine powder group, a raw material supply nozzle is provided on an upper surface of the airflow type classification apparatus, and a Coanda block is provided on a side surface side of the raw material supply nozzle, The present invention relates to a gas stream classifying device, which has a powder raw material introducing pipe for supplying a powder raw material to a rear end portion of a raw material supply nozzle and a high-pressure air introducing portion around the outer periphery of the powder raw material introducing pipe.

Further, according to the present invention, colored resin particles containing at least a binder resin and a colorant are 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 a powder raw material introducing pipe for supplying colored resin particles to the rear end, and high pressure air is introduced around the outer periphery of the powder raw material introducing pipe. And a colored resin particle is supplied to the raw material supply nozzle, and is supplied from the raw material supply nozzle in a classification area formed by a Coanda block and a plurality of classification edges installed on the side surface side of the raw material supply nozzle. A method for producing a toner, characterized in that colored resin particles according to the Coanda effect are classified into at least a coarse powder group, a medium powder group and a fine powder group, and a toner is produced from the classified medium powder group. On.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION In the gas stream classifying apparatus of the present invention and the method for manufacturing a toner using the apparatus, preferably, the raw material supply is installed at an angle of θ = 45 ° or less with respect to the vertical direction. The rear end of the nozzle is equipped with a high-pressure air inlet and a powder raw material introduction pipe, and the raw material powder is supplied from the raw material supply port above the powder raw material introduction pipe. It can be radiated from the lower part of the introduction port from the inner center of the powder raw material introduction port, and can be supplied by a raw material supply nozzle by being pressurized and dispersed on high pressure air. 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 causing turbulence of the air flow near the tip of the classification edge.

[0019]

The present invention will be described in more detail below with reference to the accompanying drawings.

FIG. 1 shows an example of an airflow classifier according to the present invention.
An apparatus of the type shown in (cross-sectional view) and FIGS. 2 and 3 (perspective view) is illustrated as a specific example.

In FIGS. 1, 2 and 3, the side walls 22 and 23 form a part of the classification chamber, and the classification edge block 2
4 and 25 have classification edges 17 and 18.
The classification edges 17 and 18 are rotatable about the shafts 17a and 18a, and the classification edge tip position can be changed by rotating the classification edge. Each classifying edge block 24 and 25 can be slid up and down, and the knife edge type classifying edges 17 and 18 are slid up and down accordingly. The classification zones of the classification chamber 32 are divided into three by the classification essences 17 and 18.

Raw material supply port 40 for introducing raw material powder
At the rear end of the raw material supply nozzle 16, a high pressure air supply unit 41 and a powder raw material introduction pipe 42 at the rear end of the raw material supply nozzle 16, and a raw material supply having an opening in the classification chamber 32. The nozzle 16 is provided on the right side of the side wall 22, and a Coanda block 26 having a long elliptical arc drawn in the extending direction of the right tangent line of the raw material supply nozzle 16 is installed. Classification room 32
The left block 27 is provided with a knife edge type air inlet edge 19 in the leftward direction of the classification chamber 32, and further, on the left side of the classification chamber 32, air inlet pipes 14 and 15 which open to the classification chamber 32 are provided. Further, the inlet pipes 14 and 15 are provided with a first gas introduction adjusting means 20 and a second gas introduction adjusting means 21, such as a damper, a static pressure gauge 28 and a static pressure gauge 29.

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

Further, on the right side of the classification chamber 32, the discharge ports 11 and 1 opened in the classification chamber in correspondence with respective fractionation areas.
2 and 13, and the outlets 11, 12 and 13 are connected to a communicating means such as a pipe, 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 portion and a pyramidal cylinder portion, and the ratio of the inner diameter of the right-angled cylinder portion to the inner diameter of the narrowest part of the pyramidal cylinder portion 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.

The classification operation in the multi-division classification area configured as described above is performed, for example, as follows. That is,
The inside of the classification chamber is decompressed through at least one of the outlets 11, 12, and 13, and the high-pressure air in the raw material supply nozzle 16 having an opening in the classification chamber and the air flow flowing by the decompression preferably have a flow rate of 50 to 300 m / The powder is ejected into the classification chamber through the raw material supply nozzle 16 at a speed of 2 seconds.

The particles in the powder introduced into the classifying chamber are curved due to the action of the Coanda effect of the Coanda block 26 and the action of gas such as inflowing air at the curved line 30a,
30b, 30c, etc. are drawn and moved, and large particles (coarse particles) are moved outside the airflow, that is, outside the classification edge 18 according to the particle size of each particle and the magnitude of the inertial force. The particles are classified into the second fraction between the classification edges 18 and 17, the small particles are classified into the third fraction inside the classification edge 17, and the classified large particles are discharged from the discharge port 11 and the classified intermediate particles. The particles are discharged from the discharge port 12,
The classified small particles are discharged from the discharge port 13, respectively.

In the classification of the powder according to this embodiment, the classification point is the position where the powder jumps out into the classification chamber 32, and the classification edges 17 and 1 with respect to the lower end portion of the Coanda block 26.
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.

In the gas stream classifier of the present invention, the raw material powder is supplied from the raw material supply port 40, and the supplied raw material powder is radiated from the lower part of the powder raw material introduction port 42 from the inner center of the powder raw material introduction port. Since the high-pressure air ejected from the high-pressure air introduction part 41 is accelerated and dispersed well, and is instantly introduced from the raw material supply nozzle 16 into the classification chamber, classified, and discharged outside the classifier system. The powder introduced into the classifier should be propelled by the propulsive force in a state where the aggregated particles are dispersed up to the primary particles without disturbing the trajectory of individual particles depending on the inlet portion in the classification chamber from the raw material supply nozzle 16. is important. The particle flow flowing from the raw material supply nozzle 16 is such that when the raw material is introduced from above, the powder flow is introduced into the classification chamber 32 having the Coanda block 26 on the side of the opening of the raw material supply nozzle 16, Since the particle trajectory is formed according to the size of the particles without disturbing the flight trajectory of, 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. When the classification edges 17 and 18 move, the edges can be oriented in the flow direction of the particle flow flying along the Coanda block 26 by the simultaneous movement of the classification edge blocks 24 and 25.

Specifically, in FIG. 5, the tip of the classification edge 17 and the side surface of the Coanda block 26 are centered around, for example, the 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 are moved up and down along the positioning member 33 by moving the classification edge block 24 up and down along the positioning member 34. It can be adjusted by moving and further rotating the tip of the classification edge 17 about the shaft 17a.

Similarly, the distance L ₅ between the tip of the classification edge 18 and the side wall of the Coanda block 26, the distance L ₂ between the side surface of the classification edge 17 and the side surface of the classification edge 18, or the side surface of the classification edge 18 and the side surface of the side wall 23. The distance L ₃ between and is moved up and down along the positioning member 35 by moving the classifying edge block 25 up and down along the positioning member 35, and the tip of the classifying edge 18 is further moved along the axis 18a. It can be adjusted by rotating it 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
4 or / and the location of the classification edge block 25 is changed, the classification area of the classification chamber is expanded, and the classification point can be easily and significantly adjusted.

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

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

The above set distance is appropriately determined according to the characteristics of the powder raw material, and the true density of the colored resin particles is 0.3 to
When 1.4g / cm ³ , L ₀ <L ₁ + L ₂ <nL ₃ (n ≧ 1: real number) When 1.4g / cm ³ is exceeded, L ₀ <L ₃ <L ₁ + L ₂ must be satisfied. Is preferred. When this is satisfied, a product (medium powder) having a sharp distribution can be efficiently obtained.

In general, the airflow classifier of the present invention is used by being connected to each other by a communication means such as a pipe and incorporated in an apparatus system. A preferred example of such a device system is shown in FIG. In the integrated device system shown in FIG. 6, the three-division classifier 1 (classification device shown in FIGS. 1 and 2), the constant quantity feeder 2, the vibration feeder 3, and the collecting cyclones 4, 5, 6 are connected by communication means. It will be.

In this apparatus system, the powder is fed to the quantitative feeder 2 by an appropriate means, and then introduced into the three-division classifier 1 by the raw material feed nozzle 16 through the vibrating feeder 3. Upon introduction, 50-30
The powder is introduced into the three-division classifier 1 at a flow rate of 0 m / sec.
The size of the classifying chamber of the three-division classifier 1 is usually [10
.About.50 cm] × [10 to 50 cm], so the powder has a density of 0.
The particles can be classified into three or more kinds of particle groups in an instant of 1 to 0.01 seconds or less. Then, the three-division classifier 1 classifies the particles into large particles (coarse particles), intermediate particles, and small particles. afterwards,
The large particles are sent to the collection cyclone 6 through the discharge conduit 11a and collected. Intermediate particles are discharged to the outside of the system through the discharge conduit 12a and collected by the collecting cyclone 5.
The small particles are discharged to the outside of the system via the discharge conduit 13a and collected. The collection cyclones 4, 5, and 6 can also function as suction decompression means for sucking and introducing the powder into the classification chamber through the raw material supply nozzle 16.

The airflow classifier of the present invention is particularly effective for classifying toners or colored resin powders for toners used in the image forming method by electrophotography. In particular, it is effective when classifying a toner composition composed of a binder resin having a low melting point, a low softening point, and a low glass transition point.

When a toner composition using such a resin is subjected to a conventional classifier, a fusion product is apt to be generated on the particle flow pipe from the injection air introduction pipe tip to the raw material supply nozzle and the classification edge tip, When a fused substance is generated, it deviates from an appropriate classification point. Then,
Even if the flow rate is adjusted by suction and decompression, it is difficult to obtain the required particle size distribution of the powder, and the classification efficiency is drastically reduced. Further, it is difficult to obtain a high-quality product because a fusion product is mixed in the classified powder.

In the classification apparatus of the present invention, the classification edges 17 and 18 are moved in the flow direction of the particle stream simultaneously with the classification edge blocks 24 and 25 to move the classification edges in the flow direction of the particle flow flying along the Coanda block 26. After passing the direction, the discharge passage pipes 11a, 12 are used as suction pressure reducing means.
By controlling the flow rate of the suction flow through a and 13a, the flight speed of particles can be increased and the dispersion of powder in the classification area can be further improved, so that the classification yield is improved and the particles at the tip of the classification edge are improved. It is possible to prevent or suppress the fusion of, and to perform highly accurate classification.

In the classifying apparatus of the present invention, the smaller the particle size of the powder, the more remarkable the effect, and particularly the weight average particle size of 10
It is possible to obtain a classified product having a sharp particle size distribution when classifying a powder having a particle size of less than or equal to μm. Furthermore, a classified product having a sharp particle size distribution can be obtained from a powder having a weight average diameter of 6 μm or less. It is possible.

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

Example 1 Styrene-butyl acrylate divinylbenzene copolymer 100 parts by weight (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

Henschel mixer (FM-7)
After thoroughly mixing with a No. 5 type, manufactured by Mitsui Miike Kakoki Co., Ltd., the mixture was kneaded with a twin-screw kneader (PCM-30 type, manufactured by Ikegai Tekko KK) 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 coarsely pulverized product was finely pulverized by a collision type air flow pulverizer to obtain a pulverized raw material having a weight average diameter of 6.7 μm, and a true density was 1.73 g / cm ³ .

35.0 kg of the obtained pulverized raw material is passed through the feeder 2 and the vibration feeder 3 and the raw material supply pipe 16 (powder raw material introducing pipe 42, high pressure air introducing portion 41 and deforming cylindrical portion 43). A multi-division classifier 1 shown in FIG. 1 was used to classify into three types of coarse powder, medium powder and fine powder by utilizing the Coanda effect at a ratio of / h.

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

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

The introduced finely pulverized raw material was instantly classified for 0.1 second 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).
Contains 1.0% by volume of particles having a particle size of 10.08 μm or more
It is possible to obtain a medium powder having a sharp distribution of (containing) in a classification yield (ratio of the finally obtained medium powder to the total amount of the pulverized raw materials charged) of 88%, which is excellent for toner. Had good performance. The classified coarse powder was recycled to the crushing step.

The true density of the toner finely pulverized powder was measured by the following measuring device in the present invention. That is, as a measuring device, Micrometrics Accupic 1330
(Manufactured by Shimadzu Corporation) was used to weigh 5 g of toner finely pulverized powder to determine the true density.

The particle size distribution of the toner can be measured by various methods, but in the present invention, it was measured using the following measuring device.

That is, as a measuring device, Coulter Counter TA-11 type or Coulter Multisizer 1 is used.
1 (manufactured by Coulter). As the electrolytic solution, an approximately 1% aqueous NaCl solution is prepared using first-grade sodium chloride. For example, ISOTONR-11 (manufactured by Coulter Scientific Japan) can be used.

As a measuring method, the electrolytic solution 100 to
To 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 electrolytic solution in which the sample is suspended is dispersed by an ultrasonic disperser for about 1 to 3 minutes,
The volume and the number of toner particles were measured by using the 100 μ-aperture as the aperture with the above-mentioned measuring device to calculate the volume distribution and the number distribution. Then, the weight-based weight average diameter determined from the volume distribution according to the present invention was determined.

Examples 2 to 4 Table 1 obtained by crushing the same coarsely pulverized product for toner production as in Example 1 with a collision type air flow pulverizer
The pulverized raw material shown in Table 1 was used to perform classification with the same apparatus system except that the set distance in the classification area shown in Table 1 was used. Table 2
As shown in Table 3 and Table 3, it was possible to efficiently obtain a medium powder having a sharp distribution, and it had excellent performance as a toner.

[0053]

[Table 1]

[0054]

[Table 2]

[0055]

[Table 3]

Examples 5-6 Unsaturated polyester resin 100 parts by weight Copper phthalocyanine pigment 4.5 parts by weight (CI Pigment Blue 15) Charge control agent 4.0 parts by weight

Henschel mixer (FM-7
After thoroughly mixing with a No. 5 type, manufactured by Mitsui Miike Kakoki Co., Ltd., the mixture was kneaded with a twin-screw kneader (PCM-30 type, 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 coarsely pulverized product was finely pulverized by a collision type air flow 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 pulverized raw material, classification was carried out in the same apparatus system as in Example 1 except that the classification conditions shown in Table 4 were used.

Further, the above-mentioned coarsely pulverized product was finely pulverized by a collision type air flow pulverizer to obtain a pulverized raw material (Example 6) having a weight average particle diameter of 5.5 μm, which was 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, the coarsely pulverized product for toner production was finely pulverized by a collision type air flow pulverizer to obtain a pulverized raw material having a weight average particle diameter of 6.9 μm ( Comparative Example 1) and a pulverized raw material (Comparative Example 2) having a weight average particle diameter of 5.5 μm were obtained.

Further, the toner raw material 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 carried out according to the flow chart of FIG. 10, and the multi-division classifiers shown in FIGS. 7, 8 and 9 were used.

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

[0068]

[Table 7]

[0069]

[Table 8]

[0070]

[Table 9]

[0071]

[Table 10]

[0072]

According to the airflow classifier of the present invention, fusion at the tip of the classifying edge can be satisfactorily prevented, and turbulent flow of the classifying airflow at the tip of the classifying edge can be satisfactorily 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 device is operating in conjunction. In particular, it is effective when classifying a toner having a weight average particle diameter of 10 μm or less.

[Brief description of drawings]

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

FIG. 2 is a perspective view of an airflow classification device of the present invention.

FIG. 3 is a perspective view of an airflow type classification device of the present invention.

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

5 is a diagram showing a main part of FIG.

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

FIG. 7 is a schematic cross-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]

 1, 101 Airflow classifier 2 Quantitative feeder 3 Vibration feeder 4, 5, 6 Collection cyclone 11, 12, 13 Discharge port 11a, 12a, 13a Discharge conduit 14, 15 Intake pipe 16 Raw material supply nozzle 17, 18, 117 , 118 Classification edge 19 Inlet edge 20 First gas introduction adjusting means 21 Second gas introduction adjusting means 22, 23 Side walls 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 Raw material supply port 41 High pressure air introduction part 42 Powder raw material introduction pipe

Claims (11)

[Claims] 1. A powder raw material supplied from a raw material supply nozzle in at least a classification area formed by a Coanda block and a plurality of classification edges, at least a coarse powder group, a medium powder group, and a fine powder due to the Coanda effect. In an airflow classifying device for classifying into groups, a raw material supply nozzle is provided on the upper surface of the airflow type classification device, and a Coanda block is provided on the side surface side of the raw material supply nozzle.
An air flow classifying device, comprising: a powder raw material introducing pipe for supplying a powder raw material to a rear end portion of the raw material supply nozzle; and a high pressure air introducing portion around an outer periphery of the powder raw material introducing pipe. 2. The raw material supply nozzle has four nozzles in the 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. The coarse powder discharge port for discharging the classified coarse powder group is installed below the fine powder discharge port for discharging the classified fine powder group. Airflow type classifier described in. 4. A powder raw material introduction pipe is installed at the center of the high pressure air supply port at the rear end of the raw material supply nozzle, and high pressure air is supplied between the outer wall of the powder raw material introduction pipe and the inner wall of the high pressure air supply port. The airflow classifier according to any one of claims 1 to 3, which has a mouth. 5. The airflow classification device according to claim 1, wherein the installation position of the classification edge is movable, and the installation position of the classification edge is changeable. 6. The airflow classification device according to claim 1, wherein the classification edge block is provided with a classification edge so that a tip of the classification edge can rotate. 7. The airflow classifying device according to claim 1, wherein the classifying edge block can move its installation position in a vertical direction or a substantially vertical direction. 8. The airflow classification device according to claim 1, wherein the classification edge can move its installation position in a vertical direction or a substantially vertical direction. 9. A method for classifying colored resin particles containing at least a binder resin and a colorant with an airflow classifier utilizing a Coanda effect, and producing a toner for developing an electrostatic charge image from the classified particles. The raw material supply nozzle installed on the upper surface of the airflow classifier is provided with a powder raw material introducing pipe for supplying colored resin particles to the rear end and a high pressure air introducing unit around the outer periphery of the powder raw material introducing pipe. In the classifying region formed by the Coanda block and the plurality of classification edges installed on the side surface side of the raw material supply nozzle, the colored resin particles are supplied to the raw material supply nozzle,
The colored resin particles supplied from 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 a toner is generated from the classified medium powder group. Toner manufacturing method. 10. A classification edge block having the classification edge is changed in its installation position so that the shape of the classification area can be changed, and the set distances of L ₀ > 0, L ₁ > 0, L _{2 are set.} > 0, L ₃ > 0 (In the formula, L ₀ indicates the height diameter of the raw material supply nozzle discharge port, L ₁ indicates the side of the classification edge for dividing into the medium powder group and the fine powder group, and Indicates the distance from the side surface of the facing Coanda block, and L ₂ is the side surface of the classification edge that separates into the medium powder group and the fine powder group, and the classification edge that separates into the coarse powder group and the medium powder group. It represents the distance between the side surface of, L ₃ is set and the side of the classifying edge demarcating coarse powder group and the medium powder group and the bisection. indicating the distance between the side surfaces of the side walls facing to) and, coloring when the true density of the resin particles is _{^{0.3~1.4g / cm 3 L 0 <L}} 1 + L 2 <nL 3 (n ≧ 1: real number) Contact classification under a Method for producing a toner according to Nau claim 9. 11. A classification edge block having the classification edge is changed in its installation position so that the shape of the classification area can be changed, and the set distances of the classification edge blocks are L ₀ > 0, L ₁ > 0, L, respectively. ₂ > 0, L ₃ > 0 (where L ₀ is the height diameter of the material supply nozzle discharge port, L ₁ is the side surface of the classification edge that divides into the medium powder group and the fine powder group, and Indicates the distance from the side surface of the Coanda block facing L, and L ₂ is the side surface of the classification edge that divides into the medium powder group and the fine powder group, and the classification that separates into the coarse powder group and the medium powder group. It represents the distance between the side edges, L ₃ is set and the side of the classifying edge demarcating coarse powder group and the medium powder group and the binary, indicates the distance between the side surfaces of the side walls facing thereto.) and, The classification is performed under the condition of L ₀ <L ₃ <L ₁ + L ₂ when the true density of the colored resin particles exceeds 1.4 g / cm ^3. Manufacturing method of the above toner.