JPH09290218A - Dispersion mixing and air flow type classifying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the size of a device and to simplify its operation by providing the inside of a raw material supplying pipe with a mixing area for mixing the upper flow and lower flow consisting of the air flow in the raw material supplying pipe and plural powder raw materials flowing together with the air flow and dispersing the powder raw materials in the air flow. SOLUTION: The classifying area is segmented to, for example, three sections by classifying edges 17, 18 disposed at a side wall 23 and a lower wall 25. The lower part of the side wall 22 is provided with the raw material supplying pipe 116 consisting of a supplying nozzle part 32 having an aperture opened to the classifying chamber and a tubular part 33. The raw material supplying pipe 116 consists of a pyramidal cylindrical part 32 which is the supplying nozzle part narrowed in the aperture to the classifying machine and a deformed cylindrical part 33 which is a uniform tubular part. This deformed cylindrical part 33 is formed as a curved pipe to mix and disperse the introduced powder in the mixing area where the direction of the pipe wall changes. As a result, the dispersed particle groups are introduced at a uniform dust concn. to the classifying area of the classifying machine 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dispersion / mixing and airflow type classifier, and more specifically, it disaggregates powder particles that are aggregated in an airflow to disperse them into primary particles, and also two types. The above fine powder is dispersed and mixed, and a mixing area for uniformly adhering another fine powder around one fine powder is provided. Two or more kinds of powder raw materials are dispersed and mixed, and continuously. The present invention relates to a dispersive mixing and airflow classifying device capable of efficiently performing classification.

[0002]

2. Description of the Related Art Conventionally, as a powder / granular mixing device,
A container rotary mixer, a fixed container mixer, a fluidized mixer, and the like are known. As shown in FIGS. 13 and 14, the container rotary type mixer is a device for mixing powder raw materials by rotating a cylindrical container or a V-shaped container. But,
Since these devices are batch-type, continuous processing is impossible, and when powder particles forming relatively hard agglomerates are mixed, crushing is not easy. Further, when a plurality of powdery or granular materials are mixed, there is a problem that a good final mixed state cannot be expected if there is a large difference in the physical properties of the raw materials.
In order to solve such a problem, a device such as a forced stirring blade or a baffle plate is attached to the inside of the mixer shown in FIGS. 13 and 14, but it has not been solved yet.

In a fixed container type mixer, a stirring screw as a stirring blade as shown in FIG. 15 rotates (rotates).
Meanwhile, a mixer having a structure in which a planetary motion (revolution) is performed in the container by the rotation of the supporting tool, and as shown in FIG.
There is a mixer having a structure in which the blades in the lower part of the mixing tank are rotated at high speed to fluidize the powder and granules in the mixing tank to perform mixing.

However, with a container-fixing type mixer having a shape as shown in FIG. 15, it is difficult to perform mixing such as crushing aggregates formed from fine particles. On the other hand, according to the mixer as shown in FIG. 16, it is possible to loosen the agglomerates to some extent by the blades rotating at a high speed, but long-term operation is indispensable for sufficient crushing. . Further, in this case, the powder particles may generate heat due to violent collision between the particles of the powder particles, and the powder particles may be deteriorated. or,
These devices put a certain amount into a certain volume,
It is difficult to obtain a uniform dispersion without mixing for a long time of several minutes to several hours. In that case, since the mixing time is long and the dust concentration in the container is high, there arises a problem that particles once dispersed re-aggregate. Such a phenomenon is more prominent as the particle size is smaller and the more highly charged powder is treated. Further, since the mixing device of this type is a batch type, continuous processing is impossible. Furthermore,
It is difficult to achieve uniform mixing in all areas of the mixing vessel.

Further, it is difficult to uniformly deposit another fine powder around one fine powder by the above-mentioned mixer. That is, in general, a toner used as a developer for electrophotography is subjected to a surface treatment for adhering and binding an inorganic or organic fine powder such as silica to the surface thereof for the purpose of improving fluidity. When the softening point of the resin fine powder used, such as toner, is low, when the raw material powder is dispersed and mixed, the toner is heated by the collision of the toner particles and melts, resulting in granulation and Inconvenience such as fusion occurs.

On the other hand, various kinds of airflow classifiers and airflow type classification methods have been conventionally proposed for classifying powder raw materials. Among these, there are a classifier using a rotary wing and a classifier without a movable part. Among them, a classifier without a movable part includes a fixed wall centrifugal classifier and an inertial force classifier. As a classifier utilizing inertial force, Loffier F. and K. Maly's "Symposiumon Powder Techn"
, and an elbow jet classifier commercialized as Nittetsu Mining Co., Ltd.
Okuda.S. And Yasu
kuni.J.) "Proc. Inter. Symp
osium on Powder Technology
y'81, 771 (1981) ”is proposed.

FIG. 10 is a sectional view of a classifier utilizing inertial force. As shown in FIG. 10, first, the powder raw material is jetted out into the classification area together with the air flow at a high speed from the opening of the raw material supply pipe 16 opening into the classifier. As shown in FIG. 10, since the Coanda block 26 is provided in the classification chamber,
When an airflow whose angle intersects with the jetted airflow is introduced, the inertial force at the time of jetting and the Coanda block 26
After the powder raw material is separated into coarse powder and fine powder by the centrifugal force of the curved air flow flowing along, coarse particles and fine powder are divided into two by coarse edges and fine edges 17 and 18 or coarse powder. And multi-division classification such as medium powder and fine powder is performed.

However, in the above classifier, the powder raw material is instantaneously introduced from the raw material supply pipe 16 into the classifier, classified, and discharged to the outside of the classifier system, so that accurate classification is performed. It is important that the powder raw material introduced into the classifier is sufficiently dispersed into individual particles by the vicinity of the raw material supply pipe 16 and the inlet of the classifier. In particular, dispersion in the pyramidal cylinder portion 16b of the raw material supply pipe 16 or the cylinder portion 16a before that is important. A side view of the tubular portion 16a while being introduced from the pyramidal tubular portion 16b into the classifier is shown in FIG. 11 (a), and a perspective view thereof is shown in FIG. 11 (b). FIG. 11B
As shown in FIG. 11, the cylindrical portion 16a has a rectangular parallelepiped shape, and the powder flowing in the cylindrical portion 16a tends to flow straight in parallel with the pipe wall (see FIG. 11 (a)). FIG.
As shown in (a), when the upper flow is A and the lower flow is B, the respective flows are substantially unhindered and are not mixed and flow in parallel along the pipe wall, It is jetted to the Coanda block 26. When the powder raw material is introduced from the upper part of the raw material supply pipe 16, the upper flow A contains a large amount of light fine powder and the lower flow B contains a large amount of heavy coarse powder.
Further, since each particle flows independently, the dispersibility tends to deteriorate.

The raw material supply pipe 1 opened to the classifier
The opening of No. 6 has a constant opening height from the surface of the Coanda block, but if the opening is too narrow, the raw material supply pipe 16 is blocked by the coarse particles in the introduced particles. On the other hand, if it is too wide, dispersion will worsen due to a decrease in flow velocity, particles will draw different trajectories depending on the site where they are introduced into the classifier, and coarse powder will disturb the trajectories of fine powder, resulting in poor classification accuracy. There is a limit to the improvement, and the classification accuracy tends to be remarkably lowered particularly in the classification of powder raw materials having a large number of coarse particles of 20 μm or more. This becomes remarkable especially when the height of the opening of the pyramidal cylinder portion 16b becomes high. Therefore, at present, in view of the balance between the clogging by coarse particles and the classification accuracy, the pyramidal cylinder portion 16b is formed.
The height of the opening of b is generally within the range of 3 to 10 mm. However, it is still not sufficient for the above reasons.

Further, the higher the dust concentration in the air stream, the more remarkable the above phenomenon. That is, if the powder raw material is sufficiently dispersed and sent to the classification chamber, ideal classification is performed, but if the dust concentration is high, insufficient dispersion is caused, and fine powder is generated due to a decrease in classification accuracy. There are problems that the yield (classification yield) of the product in the case of removal is reduced and the fine powder in the product is increased, so that the processing capacity is suppressed and the product must be used. In particular, such a problem has been remarkable when manufacturing a toner used in a copying machine or a printer.

Generally, many different properties are required for the toner, and in order to obtain a product satisfying all the required properties, the characteristics of the toner depend on the manufacturing method as well as the selection of the raw materials used. It is often decided. Therefore, for example, in the toner classification step, it is required that the toner particles obtained by classification have a sharp particle size distribution. Further, in the production of toner, it is desired to efficiently and stably produce high quality toner at low cost. Further, in recent years, in order to improve the image quality in copying machines and printers, the toner particles used are gradually becoming finer. On the other hand, in general, as the material becomes finer, the action of interparticle force increases. The same applies to resin particles and toner particles, and when it becomes a fine powder size, the cohesiveness of the particles becomes large, causing a difficult problem in manufacturing.

In particular, when a toner having a sharp particle size distribution with a weight average particle size of 10 μm or less is to be obtained, there is a problem in that the classification yield is lowered by the conventional classifying device and classifying method. Further, the weight average particle size is 8
When it is desired to obtain a toner having a sharp particle size distribution of μm or less or 6 μm or less, the classification yield is remarkably lowered by the conventional classifying device and classifying method.

From the above-mentioned points, it is necessary to continuously carry out microscopic dispersion and mixing of fine powder having a strong cohesive property and low melting point fine powder, especially fine resin powder such as toner for electrostatic charge development. Compared to the case where a conventional mechanical mixer is used, the device can be downsized, the operation can be simplified, the mixing process can be omitted, and further, highly accurate classification can be performed. Therefore, there is a demand for a dispersion mixing and classifying apparatus that can stably and efficiently obtain a powder having a sharp particle size distribution.

[0014]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a dispersive mixing and air stream classifying apparatus which solves the above-mentioned problems of the prior art in the dispersive mixing of powder and granules and the subsequent air stream classification. To do. Further, an object of the present invention is to uniformly disperse and mix two or more kinds of fine powders such as electrostatic charge developing toner and silica fine powder which is an external additive, and to make one surface of one fine powder the other. The fine powders of are adhered and bonded, or the agglomerated fine powders are dispersed to the primary particles,
A further object of the present invention is to provide a dispersion / mixing and air flow classifying apparatus which can efficiently classify powder raw materials following this and stably and efficiently obtain a fine classified product having a desired sharp particle size distribution. In particular, the object of the present invention is to uniformly disperse and mix two or more kinds of fine powders from a toner forming raw material having a weight average particle size of 10 μm or less, further 8 μm or less or 6 μm or less, and separate them on the surface of one fine powder. Provide a dispersion / mixing and airflow classifying device capable of adhering and binding the above fine powder and dispersing the agglomerated fine powder into primary particles and efficiently classifying toner particles having a sharp particle size distribution. To do.

[0015]

The above object is achieved by the present invention described below. That is, the present invention is provided with a raw material supply pipe having an opening opened in the classification area of a classifier, and two or more kinds of powder raw materials are mixed and dispersed by an air stream flowing in the raw material supply pipe. After that, the powder raw material is continuously ejected to the classification area in the classifier, and the powder raw material in the ejected air flow is in the classifier due to the inertia force of the powder raw material particles and the centrifugal force of the curved air flow due to the Coanda effect. In a dispersion-mixing and air-flow classifying apparatus in which at least coarse powder and fine powder are classified with, the air flow in the raw material supply pipe and an upper flow and a lower flow composed of two or more kinds of powder raw materials flowing with the air flow are mixed. The dispersion mixing and airflow classifying device is characterized in that at least one mixing area for dispersing the powder raw material in the airflow is provided in the raw material supply pipe.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to preferred embodiments of the present invention. First, according to the present invention, since the raw material supply pipe is provided with the mixing area, it is composed of two or more kinds of powders in the raw material supply pipe and the air flow flowing with the powders, as shown in FIG. 11 (a). By mixing such upper and lower flows and changing the flow path,
As a result of further improving the dispersion of the powder in the raw material supply pipe, it is possible to obtain good classification accuracy even with a higher dust concentration in the classification treatment that is subsequently performed, and to prevent a decrease in product yield. Also, with the same dust concentration, better classification accuracy and improved product yield are achieved. In particular, the weight average particle size is 1
When two or more kinds of fine powder of 0 μm or less are flown in the air flow, they are uniformly dispersed and mixed, and another fine powder adheres to the surface of one fine powder, or aggregated fine powder becomes primary particles. Since they are dispersed, it is possible to improve the classification accuracy and the product yield with the same dust concentration.

The dispersing and mixing and airflow type classifying apparatus of the present invention will be described below with reference to the drawings. The dispersion-mixing and air-flow classifying apparatus of the present invention is mainly composed of a part of an air-flow classifier for classifying two or more kinds of powder raw materials, and a raw material for introducing the powder raw materials into the classifier while dispersing and mixing them. It consists of a supply pipe. FIG. 1 shows a cross-sectional view of an example of the dispersion mixing and airflow type classifying device of the present invention. As shown in FIG. 1, the dispersion-mixing and airflow-type classification apparatus of the present invention has an airflow classifier 1 on the left side of the drawing and an opening opened in the classification area of the classifier, Raw material supply pipe 11 for ejecting powder raw material
6 In the example of FIG. 1, the classifier 1 divides the powder raw material into three fine powders, medium powders and coarse powders according to particle size. Hereinafter, it will be described in detail with reference to FIG.

In FIG. 1, the side walls 22, 23, 24 and the lower wall 25 have the respective shapes shown in the figure, and the side wall 23 and the lower wall 25 respectively have a knife edge type classification. Edges 17 and 18 are provided, and the classification areas 17 and 18 divide the classification area into three. A raw material supply pipe 116 including a supply nozzle portion 32 having an opening opening to the classification chamber and a tubular portion 33 is provided below the side wall 22. Below the supply nozzle portion 32, a Coanda block 26 having a shape of an elliptical arc bent downward with respect to the extension direction of the bottom tangent line is provided. The upper wall 27 of the classification chamber is provided with a knife-edge type air intake edge 19 in the lower direction of the classification chamber, and furthermore, air intake pipes 14 and 15 opening to the classification chamber are provided at the upper part of the classification chamber. Further, the intake pipes 14 and 15 are provided with first and second gas introduction adjusting means 20 and 21 such as dampers, and static pressure gauges 28 and 29. In addition, classification edge 1
The positions of 7 and 18 and the air intake edge 19 differ depending on the type of powder raw material to be subjected to the dispersion treatment or the desired particle size. Further, on the bottom of the classification chamber, discharge ports 11, 12 and 13 opened in the classification chamber corresponding to respective fractionation areas.
Is provided. The discharge ports 11, 12 and 13 may be provided with opening / closing means such as valve means.

Next, the raw material supply pipe 116 will be described in more detail with reference to the drawings. As shown in FIG. 1, the dispersion / mixing and airflow type classifier of the present invention is provided with a raw material supply pipe 116 having an opening in the classification area of the above-described airflow classifier, and the raw material supply pipe 116 is As shown in FIG. 1, a pyramidal cylinder portion 32 (hereinafter simply referred to as a pyramid cylinder portion or a cylinder portion) which is a supply nozzle portion having a narrow opening to the classifier and a deformation which is a uniform tubular portion. And a tubular portion 33 (hereinafter, simply referred to as a deformed tubular portion). In the present invention, the ratio of the inner diameter of the deforming tubular portion 33 to the inner diameter of the narrowest part of the pyramidal tubular portion 32 is 20: 1 to 1: 1, preferably 1
Set to 0: 1 to 2: 1. With this configuration, the once diverged flow can be converged to improve the flow velocity, and the propulsive force can be maintained and introduced into the classifier body. As a result, the mixed and dispersed powder raw material can be easily introduced into the classifier. Ejection velocity is obtained.

The apparatus of the present invention comprises the above-mentioned raw material supply pipe 11
In FIG. 6, there is at least a mixing area that allows the air flow flowing in the raw material supply pipe and the upper and lower flows of the powder raw material to be mixed to disperse the powder raw material in these streams. It is characterized in that it is provided at one place. In the present invention, it is preferable that at least one mixing region is provided in the deforming cylindrical portion 33 of the raw material supply pipe 116. Hereinafter, the mixing region provided in the raw material supply pipe 116, which characterizes the present invention, will be described. FIG. 3 (a) is a side view showing an example of the deformed cylinder portion 33 of the raw material supply pipe 116 of the apparatus of the present invention, and a perspective view thereof is shown in FIG. 3 (b). In this example, the shape of the tube of the deformable tubular portion 33 is a curved tube as shown in FIG. 3, and has a zigzag shape in the vertical direction. As a result, the flow path of the powder flows along the tube wall as shown by the arrow in FIG. 3 (a), and flows while the direction is changed in the mixing zone.

First, the powder introduced into the deformable cylinder portion 33 is
As shown in FIG. 3 (a), the fine powder of the upper flow A and the coarse powder of the lower flow B intersect with each other in the mixing zone x where the air flow advances straight in the direction along the pipe wall and the direction of the pipe wall changes. Mixed and
Distributed. Then, the mixed powder is mixed in the mixing area y again.
Then, the powder particles that have been mixed and similarly agglomerated in the mixing zone z are further dispersed by the particles colliding with each other or colliding with the tube wall. As a result, the raw material supply pipes 116 mix. As a result, the dispersed particle group is introduced into the classification area of the classifier 1 with a uniform dust concentration. The angle θ of the raw material supply pipe 116 with respect to the introduction direction into the classification area of the deformable cylinder portion 33 is set to 5 to 60 °, and particularly 15 to
The effect becomes remarkable at 45 °. This angle θ may be arbitrarily set within this range with respect to the powder and the flow of gas flowing together with the powder. In the present invention, the number of the mixing zones having the above-mentioned effects may be at least one, but preferably two or more to improve the dispersibility. However, if the number of mixing regions is too large, the flow of powder is hindered, and conversely pressure loss increases, which is not preferable.
In the present invention, a high powder dispersibility is obtained particularly when the mixing area is 2 to 5 places.

Although FIG. 3 described above is an example of the case where three mixing areas are provided, FIG. 4 shows an example when the number of mixing areas is two. FIG. 4A shows a side view and FIG. 4B shows a perspective view thereof. In the figure, the mixed area is x
3 and y, as in the case of FIG. 3, the upper flow A and the lower flow B intersect with each other, and the aggregated particles are mixed by the collision of particles with each other or the collision with the pipe wall. Is
Distributed. The powder raw material having good dispersibility obtained in this way is continuously ejected into the classification area of the classifier 1 through the opening of the raw material supply pipe 116, and is classified.
Therefore, good classification accuracy can be obtained even at a higher dust concentration, and it is possible to prevent a decrease in product yield.

Next, another example of the deformed cylinder portion 33 of the raw material supply pipe 116 is shown in FIG. 5, a side view of which is shown in FIG.
The perspective views are shown in FIG. The shape of the deformed cylindrical portion 33 of the raw material supply pipe in FIG. 5 is a smoothly bent curved pipe, and the agglomerated powder particles introduced into the raw material supply pipe are along the pipe wall as indicated by arrows. Flow and are mixed in two mixing zones of mixing zones x and y, and the particles collide with each other or collide with the wall surface and are well dispersed. As described above, it is preferable to use a curved tube in which the shape of the deformable tubular portion 33 is smoothly bent, because the flow velocity can be suppressed from being reduced and the particles can have a propulsive force.

FIG. 6 shows a deformed cylindrical portion 33 of the raw material supply pipe 116.
The case where the number of mixing zones provided in 1 is 1 is shown. A side view thereof is shown in FIG. 6 (a), and a perspective view thereof is shown in FIG. 6 (b).
In the present invention, if the raw material supply pipe is provided with one mixing region for dispersing the powder raw material, the dispersibility is considerably improved. The dispersibility is further improved by setting the number of points to 5.

FIG. 7 shows an example in which the deforming cylinder portion 33 of the raw material supply pipe 116 is V-shaped. A side view thereof is shown in FIG. 7 (a), and a perspective view thereof is shown in FIG. 7 (b). In this example, as shown in FIG. 7 (a), the mixing region is represented by x,
There are three locations represented by y and z. Further, in this example, since the deforming cylinder portion 33 has a V-shape, it is possible to suppress the reduction of the flow velocity and to give propulsive force to the particles, as compared with the case of the zigzag curved pipe shown in FIG. It is preferable in terms.

In each of the above-mentioned examples, an air flow flowing in the raw material supply pipe and an upper flow and a lower flow made of the powder raw material are mixed to form a mixing region for dispersing the powder raw material.
Although it is formed by forming the deformed cylindrical portion 33 of the raw material supply pipe into a curved pipe, as shown in FIGS. 8 and 9, a flow path control plate is provided in the deformed cylindrical portion 33 of the raw material supply pipe. 40
By providing, a mixing zone for dispersing the powder raw material may be provided. In the example shown in FIG. 8, the raw material supply pipe 1
A portion of the 16 deformed cylindrical portions 33 is formed of a straight pipe as in the conventional case (see FIG. 10), and a flow path control plate 40 is alternately provided on the upper inner wall and the lower inner wall to form a mixing region. . FIG. 8A is a side view thereof, and FIG.
Shows a perspective view.

As shown in FIG. 8A, the flow of the powder and the gas flowing with the powder is changed by colliding with the flow path control plate 40, and at that time, the upper flow A and the lower flow B are changed. The powder and granules divided into are mixed and dispersed in the mixing zones x, y and z. In the present invention, as shown in FIG.
The length of the flow path control plate 40 is L ₁ , and the height of the deformable tubular portion 33 is L _2.
In this case, it is preferable to provide the flow path control plate 40 such that L ₁ and L ₂ satisfy the following formula. With this configuration, the air flow containing the raw material powder is forcibly changed to the zigzag shape in the flow path, so that the raw material powder is mixed and dispersed. Further, the powder is crushed and sufficiently dispersed by the effect of collision with the flow path control plate 40.

Further, FIG. 9 shows an example in which the shape of the deformable cylindrical portion 33 provided with the flow path control plate 40 is different from the above example. 9 (a) is a side view thereof, and FIG. 9 (b) is a perspective view thereof. As in the example shown in FIG. 8, as shown in FIG. 9 (a), the flow path is changed by the flow path control plate 40, and the particles are mixed in the mixing regions x, y, z of the upper inner wall and the lower part. The upper flow A and the lower flow B are mixed in five mixing regions of α and β on the inner wall, the coarse powder and the fine powder are mixed, the dust concentration becomes uniform, and the mixture is ejected to the classification region. At this time, the number and height of the flow path control plates 40 are appropriately determined according to the properties of the powder used. Further, the set position and the set number may be provided at an arbitrary position on the inner wall surface, and are not particularly limited. However, also in this case, the dispersibility becomes better when the number of mixing regions is two or more than one.
Further, the effect is more remarkable as the particle diameter of the powder raw material is finer, and particularly when the weight average particle diameter is 8 μm or less or 6 μm or less.

As described above, in the dispersion mixing and air flow type classifying apparatus of the present invention, the upper flow and the lower flow of the air current and the powder raw material flowing together with the air flow are mixed in the raw material supply pipe to produce the powder. It suffices to provide at least one mixing zone for dispersing the body raw material so as to improve the dispersibility of the powder raw material introduced into the classifier. Therefore, the raw material supply pipe 11
The shape of the deformed cylindrical portion 33 of No. 6 and the shape and installation method of the flow path control plate 40 provided on the inner wall thereof may be determined according to the property of the powder to be treated, and are not limited. As an example of dispersing and mixing two kinds of powder raw materials using the dispersion mixing and airflow classifying device of the present invention, uniformly adhering another fine powder around one fine powder, and classifying this For example, there is a case where the surface of the toner raw material is subjected to a surface treatment of adhering and mixing an inorganic substance such as silica or an organic fine powder for continuous classification. At this time, the weight average particle diameter of the toner raw material powder is 10 μm. It is effective in the following cases, and is particularly effective in the case of 6 μm or less.

Means for charging the powder raw material into the raw material supply pipe 116 together with the air flow is 0.09 to 0.59 MPa.
Pressure, the air is blown in the downstream of the classification area and the negative pressure in the classification area is increased to naturally suck the outside air and powder, or the raw material is injected into the inlet. There is a method in which a feeder is mounted so that outside air and powder are sucked by the feeder, and at the same time, the powder is sent to the classification area through the raw material supply pipe 116. In the present invention, among the above-mentioned three charging means, from the viewpoint of the apparatus surface and the operating conditions, in particular, the method and the method of increasing the negative pressure in the classification area to naturally suck the outside air and the powder are used. A method using a zection feeder is preferable.

Further, the present invention is more effective in classifying the toner for electrostatic charge development, which is required to have a sharp particle size distribution such as containing 50% by number or more of particles having a particle size of 20 μm or less and a highly accurate classification accuracy. In addition to the two-division classification, more preferable effects can be obtained by the multi-division classification. Furthermore, after dispersing and mixing a toner having a weight average particle size of 8 μm or less,
In the subsequent continuous classification process,
Further effects can be obtained.

Next, the classification treatment which is carried out subsequently after the dispersion and mixing to obtain the powder raw material having the good dispersibility in the raw material supply pipe 116 as described above will be described.
For example, the classification operation in the three-division classification area is performed as follows. First, the inside of the classification area is decompressed through at least one of the outlets 11, 12 and 13 of the classifier shown in FIG. 1, and the powder having good dispersibility is obtained by the flowing air flow in the raw material supply pipe 116 caused by this decompression. The body raw material is supplied to the classification area in the classifier at a flow rate of 50 to 300 m / sec through the pyramidal cylinder portion 32 of the raw material supply pipe 116 having an opening opening to the classification area. In the present invention, as described above, by changing the shape of the deforming cylinder portion 33 of the raw material supply pipe 116 and the state inside the pipe, the upper flow and the lower flow are mixed and flow with the air flow and the air flow. By changing the flow path of the raw material powder, the cohesiveness of the powder and granules is reduced and the dispersibility is improved. As a result, the final classification efficiency is improved.

The powder raw material supplied into the classifier as described above is in the classifying zone in the classifier and is the Coanda block 26.
The Coanda effect due to the action of and the action of gas such as air that flows in at that time move along the curved line 30,
Each is classified according to the size of the particle size. That is, large particles (coarse particles) are in the fraction outside the classification edge 18, which is the outside of the air flow, and intermediate particles (particles with a standard particle size) are small in the fraction between the classification edges 17 and 18. The particles (particles with a size smaller than the standard particle size) are divided into fractions inside the classification edge 17, respectively. The large particles are discharged through the discharge port 11, the intermediate particles are discharged through the discharge port 12, and the small particles are discharged through the discharge port 13.

When the above-mentioned dispersion mixing and classification method is carried out by the apparatus of the present invention, it is usually used as an integrated apparatus system in which mutual devices are connected by a communicating means such as a pipe. A preferred example of such an integrated device system is shown in FIG. In FIG. 2, reference numeral 1 is a three-division classifier which constitutes the same dispersing and mixing and airflow type classifying apparatus of the present invention as shown in FIG. 1, and the details are as described above. Reference numeral 116 denotes a raw material supply pipe, and as described above, it is formed of the pyramidal cylinder portion 32 having the opening portion that opens to the classifier 1 and the deforming cylinder portion 33. The deforming cylinder portion 33 is shown in FIG. It consists of a zigzag bent tube as in the example shown in. Reference numeral 2 is a powder material quantitative supply device, 3 is a vibrating feeder, and the collecting cyclones 4, 5 and 6 are connected to the classifier 1 by a communicating means.

In the above-mentioned apparatus system, the powder raw material is fed to the constant amount feeder 2 by an appropriate means, and then introduced into the three-division classifier 1 through the vibrating feeder 3 by the raw material feed pipe 116. At the time of introduction, the powder raw material should be introduced into the three-division classifier 1 at a flow rate of 50 to 300 m / sec so that the particles are dispersed and mixed, and the particles are disentangled and a propulsive force is exerted to achieve efficient classification. Is preferred. When the powder raw material is introduced at such a flow rate, the size of the classification area of the three-division classifier 1 is usually [10 to 50 cm].
X [10 to 50 cm], the powder raw material was
It is possible to classify into 3 or more types of particle groups at an instant of 1 second or less, or 0.01 seconds or less. In the example shown in FIG. 2, a three-division classifier 1
Depending on the size, large particles (coarse particles), intermediate particles (particles with a specified particle size), small particles (particles with a particle size less than the specified size)
Is divided into After that, the large particles are discharged to the outside of the system through the discharge conduit 11 ′, sent to the collecting cyclone 6 and collected. The intermediate particles are discharged to the outside of the system through the discharge conduit 12 ', and are collected as much as the product 51 by the collection cyclone 5. The small particles are discharged to the outside of the system via the discharge conduit 13 'and collected by the collection cyclone 4 as fine powder 41 having a non-regulated particle diameter. The collection cyclones 4, 5 and 6 also serve as suction decompression means when suctioning and introducing the powder raw material into the classification area through the raw material introduction pipe.

In the above apparatus system, the powder raw material is introduced into the raw material supply pipe 116 via the powder raw material quantitative feeder 2 and the vibration feeder 3, and the diffuser in the raw material supply pipe 116 following the throat portion. The particles are expanded, and the particles are dispersed upstream and downstream while giving a propulsive force to the particles,
Further, the upper and lower streams are mixed to make it possible to continuously perform microscopic dispersion mixing of fine powder having a strong cohesive property, fine powder having a low melting point, etc. in a short time, and the conventional method as shown in FIGS. Compared with the mechanical mixer of (1), the apparatus can be downsized, the operation can be simplified, and the mixing process can be omitted, so that the equipment investment can be reduced and the production can be performed at low cost.

In an apparatus system in which the dispersion / mixing and air flow type classifying apparatus of the present invention as described above is used, two kinds of fine powders of electrostatic charge developing toner and silica fine powder are charged as powder raw materials and weighted. When a toner raw material containing 50% by number or more of particles having an average particle diameter of 20 μm or less was classified,
We were able to classify more efficiently than before. Further, when the obtained classified product was observed with an electron microscope, it was confirmed that silica was uniformly attached to the surface of the toner particles.

In particular, it is possible to obtain a toner having a sharp particle size distribution and confirmed to have silica uniformly attached to the surface of the toner particles, from a toner raw material having a weight average particle diameter of 10 μm or less. there were. Further, even from a toner raw material having a weight average particle diameter of 6 μm or less, a toner having a sharp particle size distribution and having silica uniformly adhered to the particle surface could be obtained.

[0039]

As described above, according to the present invention, for example, it is possible to efficiently obtain toner particles having a sharp particle size distribution from a toner raw material having a weight average particle diameter of 10 μm or less. It is possible to efficiently obtain toner particles having a sharp particle size distribution from a toner raw material having a weight average particle diameter of 8 μm or less, or 6 μm or less, and it is possible to improve the quality of the obtained toner and to perform stable production. Further, according to the present invention, for example, when two kinds of electrostatic charge developing toner and silica fine powder are used as powder raw materials, the two kinds of fine powder are uniformly dispersed and mixed, and the fine powder is converted into primary particles. As a result of being able to disperse and silica uniformly adhering to the surface of the toner, followed by high-precision classification, a toner having a sharp particle size distribution can be obtained. In particular, a toner containing 50 number% or more of particles having a weight average particle diameter of 20 μm or less can be efficiently dispersed and mixed, and then classified by a classification treatment. Further, according to the present invention, the apparatus can be downsized as compared with the case of using the conventional mechanical mixer, and the mixing step can be omitted only by forming the raw material supply pipe to the airflow classifier into a specific configuration. It is possible to simplify the operation,
For example, it is possible to reduce the capital investment in toner manufacturing and to manufacture toner at low cost.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of a dispersion / mixing and airflow type classification device of the present invention.

2 is a diagram showing an integrated device system using the device shown in FIG. 1. FIG.

FIG. 3 is a side cross-sectional view and a perspective view showing an example of a deformed cylinder portion of a raw material supply pipe.

FIG. 4 is a side cross-sectional view and a perspective view showing another example of the modified cylinder portion of the raw material supply pipe.

5A and 5B are a side sectional view and a perspective view showing another example of the deformed cylinder portion of the raw material supply pipe.

FIG. 6 is a side cross-sectional view and a perspective view showing another example of the deformed cylinder portion of the raw material supply pipe.

7A and 7B are a side sectional view and a perspective view showing another example of the modified cylinder portion of the raw material supply pipe.

8A and 8B are a side sectional view and a perspective view showing another example of the deformed cylinder portion of the raw material supply pipe.

9A and 9B are a side sectional view and a perspective view showing another example of the deformed cylinder portion of the raw material supply pipe.

FIG. 10 is a cross-sectional view showing an airflow classifier having a conventional raw material supply pipe.

FIG. 11 is a side sectional view and a perspective view showing a straight tubular portion of a conventional raw material supply pipe.

FIG. 12 is a view showing an integrated device system having a conventional raw material supply pipe.

FIG. 13 is a cross-sectional view showing a conventional mixer.

FIG. 14 is a sectional view showing a conventional mixer.

FIG. 15 is a cross-sectional view showing a conventional mixer.

FIG. 16 is a cross-sectional view showing a conventional mixer.

[Explanation of symbols]

 1: 3 division classifier 2: Fixed amount feeder 3: Vibratory feeder 4, 5, 6: Collection cyclone 11, 12, 13: Discharge port 11 ', 12', 13 ': Discharge conduit 14, 15: Inlet port 16, 116: Raw material supply pipe 16a: Cylindrical part 16b: Pyramidal cylinder part 17, 18: Classification edge 19: Inlet edge 20: First gas introduction adjusting means 21: Second gas introduction adjusting means 22, 23, 24: Side wall 25: Lower wall 26: Coanda block 27: Upper wall 28, 29: Static pressure gauge 30: Solid particle scattering direction 31: Injection feeder 32: Pyramidal cylinder of raw material supply pipe 33: Deformation cylindrical portion of raw material supply pipe 40: Flow control plate

Claims (4)

[Claims] 1. A raw material supply pipe having an opening opened in a classification area of a classifier is provided, and two or more kinds of powder raw materials are mixed and dispersed by an air stream flowing in the raw material supply pipe. After that, the powder raw material is continuously ejected to the classification area in the classifier, and the powder raw material in the jet stream is generated in the classifier by the inertia force of the powder raw material particles and the centrifugal force of the curved air flow due to the Coanda effect. In a dispersion-mixing and air-flow classifying device in which at least coarse powder and fine powder are classified, an air flow in a raw material supply pipe and an upper flow and a lower flow composed of two or more kinds of powder raw materials flowing with the air flow are mixed. A dispersion / mixing and airflow type classification device, characterized in that at least one mixing area for dispersing the powder raw material in the airflow is provided in the raw material supply pipe. 2. The dispersive mixing and airflow classifying apparatus according to claim 1, wherein the raw material supply pipe is composed of a deforming cylinder portion and a pipe portion, and at least one mixing zone is provided in the deforming cylinder portion. 3. The dispersive mixing and airflow type classifying device according to claim 2, wherein the deformable cylinder portion is formed of a curved pipe. 4. The dispersive mixing and airflow classifying device according to claim 2, wherein the deformable cylinder is a straight pipe, and a plurality of flow path control plates are provided on the upper inner wall and the lower inner wall.