JPH08141509A - Air flow type classifying apparatus and preparation of toner - Google Patents

Abstract

PURPOSE: To provide an air flow type classifying apparatus which gives an accurate classifying point, makes more highly accurate classification possible and can produce efficiently a powder with a precise particle size distribution and a method for preparing a toner by using the air flow type classifying apparatus. CONSTITUTION: An air flow type classifying apparatus for classifying a powdery raw material fed from a raw material feeding nozzle into at least a coarse powder group, an intermediate powder group and a fine powder group based on a Coanda effect in a classifying region formed at least of a Coanda block and a plurality of classification edges 17 and 18, is provided and the air flow type classifying apparatus wherein the installed positions of classification edge blocks 24 and 25 providing classification edges 17 and 18 can be changed so as to change the shape of the classifying region, is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an airflow classifying device for classifying powder by utilizing the Coanda effect. In particular, the present invention, in order to efficiently classify powder containing 50% by number or more of particles having a particle size of 20 μm or less, carry the powder by carrying it in an air stream, and at the same time, use the Coanda effect and the particles of each particle in the powder. The present invention relates to an airflow type classifying device for classifying particles having a predetermined particle size based on a difference in inertial force, centrifugal force or the like according to a diameter.

Further, the present invention relates to a method for producing a toner by using an air flow classifier for classifying colored resin powder by utilizing the Coanda effect. In particular, in order to efficiently classify the colored resin powder containing 50% by number or more of particles having a particle size of 20 μm or less, the present invention carries the colored resin powder by carrying it in an air stream, and at the same time, the Coanda effect, The present invention relates to a method for producing a toner for developing an electrostatic charge image by classifying a colored resin particle group having a predetermined particle size based on a difference in inertial force, centrifugal force, etc. according to the particle size of each particle.

[0003]

2. Description of the Related Art For classifying powders, air-flow classifying apparatuses of various methods have been proposed. Among them, there are classifiers that use rotary blades and classifiers that have no moving parts. this house,
Fixed-wall centrifugal classifiers and inertial force classifiers are classifiers with no moving parts. Lo as a classifier that uses inertial force
ffier. F. and K. Maly: Symp o
n Powder Techn D2 (1981), an elbow jet classifier commercialized by Nippon Steel Mining Co., Ltd., and Okuda. S. and Yasuku
ni. J. Proc. Inter. Symposium
on Powder Techn '81, 771
The classifier exemplified in (1981) has been proposed as an inertial force classifier capable of classifying in a fine powder region.

These air flow type classifiers are shown in FIGS.
As shown in, the raw material supply nozzle 16 having an opening in the classifying chamber ejects the powder into the classifying chamber at high speed with an air stream,
A Coanda block 26 is provided in the classifying chamber, and an air flow intersecting with an air flow ejected from a raw material supply nozzle is introduced to the coarse powder group, medium powder group, and fine powder group by centrifugal force of a curved air stream flowing along the Coanda block 26. The coarse powder group, the medium powder group, and the fine powder group are classified by the classifying edge 117 and the classifying unit 118 which are separated into groups and whose tip is thin.

However, in the conventional classifying device 101,
Classification edge block 124 and classification edge block 12
5 is fixed, and by adjusting the tip positions of the classification edge 117 and the classification edge 118 and adjusting the flow rate of the airflow for classification accordingly, the classification point (that is, the size of the particle that becomes the boundary of classification) ) Is set to the 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 predetermined flow rate is controlled accordingly. In this way, if only the tip positions of the classification edges 117 and 118 are adjusted,
Depending on the angle, turbulence of the air flow is likely to occur near the tip of the edge, and as a result, accurate classification may not be obtained, and other particle groups should be of a uniform size. In some cases, particles of a size that should enter can be mixed. Even if you want to change the classification point, you cannot change the position of the classification edge along the direction of the air flow even if you change the tip position of the classification edge and control the flow rate accordingly. Not only does it take time to adjust the value to a predetermined value, but there is also a problem to be improved such as a decrease in classification accuracy. In particular, such a problem is likely to become apparent during classification for producing an electrostatic charge image developing toner used in a copying machine, a printer or the like.

Generally, toners are required to have many different properties. Toner properties are affected by the raw materials used for the toner, and often by the method of manufacturing the toner. In the classification step for producing a toner, it is required that the classified toner particle group has a sharp particle size distribution, and it is desired to efficiently and stably produce a high-quality toner at low cost.

Generally, 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, and a colored resin powder containing such a resin is classified. When introduced into a machine and classified, adhesion or fusion easily occurs in the classifier.

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

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 substance has a small size, the cohesiveness between the particles increases.

When an external force such as an impact force or a frictional force acts on such an aggregate of particles, the particles are likely to be fused in the classifying device. In particular, fusion is likely to occur at the tip of the classification edge, and if such a phenomenon occurs, the classification accuracy will deteriorate and the classifier will not operate in a stable state at all times, so that high-quality classified powder will be stable for a long period of time. Hard to get.

In view of the above points, there is a demand for an airflow type classifying apparatus which can classify colored resin fine powders such as toners stably, efficiently and accurately.

[0012]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an air flow type classifier which solves the above problems.

It is an object of the present invention to provide an air flow type classifying device which enables accurate classification by setting an accurate classifying point and can efficiently produce a powder having a fine particle size distribution. .

Another object of the present invention is to provide an air flow type classifying apparatus which is less likely to cause fusion in the classifying area and which does not cause a change in the classifying point in the apparatus and which is capable of stable classification.

Further, it is an object of the present invention to provide an air flow type classifying device which can greatly change the classifying point.

Further, an object of the present invention is to provide an air flow type classification device which can change the classification point in a short time.

An object of the present invention is to provide a method of manufacturing a toner for developing an electrostatic charge image, which solves the above problems.

An object of the present invention is to provide a method for producing a toner, which enables accurate classification by setting an accurate classification point and efficiently produces a powder having a fine particle size distribution. is there.

Another object of the present invention is to provide a method for producing a toner in which fusion is less likely to occur and the classification point does not fluctuate in the apparatus, and stable classification is possible.

A further object of the present invention is to provide a method for producing a toner whose classification point can be greatly changed.

A further object of the present invention is to provide a method for producing a toner capable of changing the classification point in a short time.

[0022]

According to the present invention, at least a coarse powder is produced by a Coanda effect from a powder raw material supplied from a raw material supply nozzle in a classification area formed by at least a Coanda block and a plurality of classification edges. An air classifier for classifying a body group, a medium powder group and a fine powder group, and a classification edge block having the classification edge,
The present invention relates to an air flow type classification device, characterized in that its installation position can be changed so that the shape of a classification region can be changed.

Further, according to the present invention, the true density is 0.3 to 1.4.
The colored resin powder having g / cm ³ is supplied to the raw material supply nozzle, and the colored resin powder is conveyed by the airflow flowing in the raw material supply nozzle, and is fed to the classification chamber formed between the Coanda block and the side wall. The colored resin powder is introduced, and the colored resin powder is classified by the Coanda effect, separated into at least a coarse powder group, a medium powder group, and a fine powder group by a plurality of classification edges, and the separated medium powder group A method of manufacturing a toner from the above, wherein the installation positions of the classification edge blocks each of which has a classification edge and whose installation position can be changed are set to the following conditions L ₀ > 0, L ₁ > 0, L ₂ > 0, L ₃ > 0 L ₀ <L
₁ + L ₂ <nL ₃ [where L ₀ is the height diameter of the discharge port of the raw material supply nozzle (m
m), L ₁ represents the distance (mm) between the side surface of the first classification edge for fractionating into the medium powder group and the fine powder group, and the side surface of the Coanda block facing this, L ₂ Is the first
The distance (mm) between the side surface of the classification edge and the side surface of the second classification edge for fractionating into the coarse powder group and the medium powder group is shown.
L ₃ represents the distance (mm) between the side surface of the second classification edge and the side surface of the side wall facing the second classification edge, and n is a real number of 1 or more]. The present invention relates to a toner manufacturing method.

Further, according to the present invention, the true density is 1.4 g / cm ³
The colored resin powder exceeding the above is supplied to the raw material supply nozzle, and the colored resin powder is conveyed by the airflow flowing in the raw material supply nozzle,
The colored resin powder is supplied to the classifying chamber formed between the Coanda block and the side wall, and the colored resin powder is classified by the Coanda effect so that at least the coarse powder group, the medium powder group, and the fine powder group. A method of manufacturing a toner from a group of medium powders separated by a plurality of classification edges, wherein the classification edge blocks each having a classification edge whose position can be changed are installed under the following condition L _0. > 0, L ₁ > 0, L ₂ > 0, L ₃ > 0 L ₀ <L
₃ <L ₁ + L ₂ [where L ₀ is the height diameter of the discharge port of the raw material supply nozzle (m
m), L ₁ represents the distance (mm) between the side surface of the first classification edge for fractionating into the medium powder group and the fine powder group, and the side surface of the Coanda block facing this, L ₂ Is the first
The distance (mm) between the side surface of the classification edge and the side surface of the second classification edge for fractionating into the coarse powder group and the medium powder group is shown.
L ₃ indicates the distance (mm) between the side surface of the second classification edge and the side surface of the side wall facing the second classification edge].

In the airflow type classifying apparatus of the present invention, the shape of the classifying area can be changed by changing the installation position of the classifying edge block having the classifying edge, and the classifying points can be easily and significantly changed accordingly. It can be changed.
By changing the installation position of the classification edge along with the change of the installation position of the classification edge block, the tip of the classification edge can be rotated and the position of the tip of the classification edge can be adjusted.
The classification point can be changed significantly, and the classification point can be accurately adjusted without causing turbulence of the air flow near the tip of the classification edge.

[0026]

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

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

1 and 2 and 3, the side walls 22 and 23 form part of a classification chamber, and a classification edge block 24.
Comprises a first classification edge 17 and a classification edge block 2
5 has a second classification edge 18. The classification edges 17 and 18 are rotatable around the first shaft 17a and the second shaft 18a, and the classification edge tip position can be changed by rotating the classification edge. The classification edge blocks 24 and 25 can be slid left and right, and the knife edge type classification edges 17 and 18 are slid left and right in the same direction or substantially the same direction.

Due to the classifying edges 17 and 18, the classifying zone of the classifying chamber 32 forms a first classifying region formed between the Coanda block for separating fine powder particles having a predetermined particle size or less and the first classifying edge. And a second classification area formed between a first classification edge and a second classification edge for separating a medium powder group having a predetermined particle size, and for separating a coarse powder group having a predetermined particle size or more. It is divided into three parts in the third classification area.

A raw material supply nozzle 16 having an opening in a classifying chamber 32 is provided below the side wall 22, and a Coanda block 26 having a long elliptical arc in the direction of extension of the bottom tangent line of the raw material supply nozzle is installed. The upper block 27 of the classification chamber 32 is provided with a knife-edge type air inlet edge 19 in the lower direction of the classification chamber 32, and further, the air inlet pipes 14 and 15 opening to the classification chamber 32 are provided above the classification chamber 32. . 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.

The bottom surface of the classification chamber 32 has discharge ports 11, 12 and 13 which open into the classification chambers corresponding to the respective classification areas. The discharge ports 11, 12 and 13 are provided with communication means such as pipes. They are connected and each may be provided with opening and closing means such as 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 narrowest portion of the pyramid cylinder portion is 20: 1 to 1: 1, preferably 10 :. Setting from 1 to 2: 1 gives good introduction rates. At the rear end portion of the raw material supply nozzle 16, a supply port for supplying powder to the nozzle and an injection air introduction pipe 31 for supplying air for conveying the powder are provided.

The classification operation in the multi-division classification area configured as described above is performed as follows, for example. Outlet 11,
The inside of the classification chamber is decompressed through at least one of 12 and 13, and the high-pressure air flow from the injection air introduction pipe 31 and the air flow flowing by the decompression in the raw material supply nozzle 16 having an opening in the classification chamber are preferable. Raw material supply nozzle 1 for powder at a flow velocity of 50 to 300 m / sec.
It spouts to the classification room through 6.

The particles in the powder introduced into the classifying chamber are curved by 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 moved, and depending on the size of each particle and the magnitude of the inertial force, the large particles (coarse particles) are the first fraction and the middle of the outside of the air flow (that is, the outside of the classification edge 18). Particles are classified into the second fraction between the classification edges 18 and 17, 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 classified. 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 the present embodiment, the classification point is the position where the powder jumps out 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 or the ejection speed of the powder from the raw material supply nozzle 16.

In the gas stream classifier of the present invention, when the powder is introduced into the classifying chamber 32, the particles are dispersed according to the size of the particles in the powder to form a particle flow. It is possible to move the classification edge in the direction and then fix the edge tip position of the classification edge to set it at a predetermined classification point. Simultaneous movement of the classification edges 17 and 18 with the classification edge blocks 24 and 25 allows the edges to be oriented in the flow direction of the particle flow flying along the Coanda block 26.

Specifically, in FIG. 4, the tip of the classification edge 17 and the wall surface of the Coanda block 26 are centered around, for example, the position O in the Coanda block 26 corresponding to the lower portion of the tip opening 16a of the raw material supply nozzle 16. Distance L ₄
Moves the classification edge block 24 left and right along the positioning member 33 to move the classification edge 17 left and right along the positioning member 34, and further moves the classification edge 1
It can be adjusted by rotating the tip of 7 around the shaft 17a. Similarly, the distance L ₅ between the tip of the classification edge 18 and the wall surface of the Coanda block 26 is set so that the classification edge 18 is moved right and left along the positioning member 36 by moving the classification edge block 25 left and right along the positioning member 35. To the shaft 18 and the tip of the classification edge 18
It can be adjusted by rotating around a.
With the change of the installation position of the classification edge block 24 and / or the classification edge block 25, the shape of the classification area of the classification chamber changes, and the classification point can be adjusted easily and largely.

That is, each classification edge is rotatably supported by a shaft, and the distance between the first shaft supporting the first classification edge and the Coanda block can be changed. It is possible to change the distance between the second shaft supporting the second classification edge and the first shaft, and it is possible to change the distance between the second shaft and the side wall. is there.

Therefore, turbulence of the flow due to the tip of the classification edge can be prevented, and the flight speed of particles can be increased by adjusting the flow rate of the suction flow due to the reduced pressure through the discharge conduits 11a, 12a, 13a, and thus in the classification region. The dispersion of the powder is improved, good classification accuracy can be obtained even at high dust concentration, and not only can the decrease in product yield be prevented, but the same dust concentration can also improve classification accuracy and product yield. It will be possible.

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 amount and inflow velocity of the gas from 15.

Further, when the colored resin powder is classified for producing the toner, L ₀ , L ₁ , L ₂ shown in FIG.
It is preferable to adjust L ₃ , L ₄ , L ₅ and L ₆ as follows.

In FIG. 5, the distance L between the tip of the first classification edge 17 and the side surface of the Coanda block 26 is centered on, for example, the position O in the Coanda block 26 corresponding to the lower portion of the tip opening 16a of the raw material supply nozzle 16. ₄ and 1
The distance L ₁ between the side surface of the classification edge 17 and the side surface of the Coanda block 26 is set so that the first classification edge 17 is moved along the positioning member 34 by moving the first classification edge block 24 left and right along the positioning member 33. Move left and right,
Further, it can be adjusted by rotating the tip of the first classification edge 17 about the first shaft 17a.

[0044] Similarly, the distance L ₂ between the side surface and the side surface of the second classifying edge 18 of the distance L ₅ and first classifying edge 17 between the tip and the wall surface of the Coanda block 26 of the second classifying edge 18
Alternatively, the distance L ₃ between the side surface of the second classification edge 18 and the side surface of the side wall 23 can be adjusted by moving the second classification edge block 25 left and right along the positioning member 35 so that the second classification edge along the positioning member 36. Move 18 left and right,
Further, it can be adjusted by rotating the tip of the second classification edge 18 about the second shaft 18a. That is, as the installation position of the first classification edge block 24 and / or the second classification edge block 25 is changed, the shape of the classification area of the classification chamber changes, 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 flow rate of the suction flow due to the reduced pressure via the discharge conduits 11a, 12a and 13a can be adjusted to increase the flight speed of the particles and to increase By improving the dispersion of finely pulverized material in the classification area and obtaining good classification accuracy even at a higher dust concentration, it is possible not only to prevent the yield of the product from decreasing, but at the same dust concentration, a better classification accuracy and product It is possible to improve the yield.

The distance L6 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 shaft 19a, whereby the inlet tubes 14 and 15 are adjusted. Further adjustment of the classification point is possible by adjusting the inflow rate and the inflow rate of gas from the.

The above-mentioned set distance is appropriately determined according to the characteristics of the pulverized raw material, and the true density of the finely pulverized material is 0.3 to 1.
When 4 g / cm ³ , L ₀ <L ₁ + L ₂ <nL ₃ (n ≧ 1: real number) When 1.4 g / cm ³ or more, it is necessary to satisfy L ₀ <L ₃ <L ₁ + L ₂ Is. If you are satisfied with this,
It is possible to efficiently obtain a product (medium powder) having a sharp distribution. Specifically, L ₀ is ₂ to 10 mm, L ₁ is 10 to 150 mm, and L ₂ is 10 to 15
0 mm, L ₃ is 10 to 150 mm, L ₄ is 5 to 70 mm, L ₅ is 15 to 160 mm,
L ₆ is 10 to 100 mm, and n is 0.5 to 3
Is preferable in order to accurately classify powder containing 50% by number or more of particles having a particle size of 20 μm or less for a long period of time.

In general, the airflow type classifying apparatus of the present invention is used by being connected to each other by a communicating means such as a pipe and incorporated in an apparatus system. A preferred example of such a device system is shown in FIG. The integrated device system shown in FIG. 6 includes a three-division classifier 1 (classification device shown in FIGS. 1 and 2), a constant quantity feeder 2, a vibration feeder 3, a collection cyclone 4, a collection cyclone 5, and a collection cyclone 6. Are connected by a communication means.

In this apparatus system, the powder is sent 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 classification chamber of the three-division classifier 1 is usually [10
.About.50 cm] × [10-50 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 particle groups (coarse particles), intermediate particle groups, and small particle groups. After that, the large particle group passes through the discharge conduit 11a,
It is sent to the collection cyclone 6 and collected. The intermediate particle group is discharged to the outside of the system through the discharge conduit 12a and collected by the collecting cyclone 5. The small particle group is discharged to the outside of the system through the discharge conduit 13a and collected by the collecting cyclone 4. 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 type classifying apparatus of the present invention is particularly effective for classifying the toner or the colored resin powder for toner 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 fused substance is likely to be generated at the tip of the classification edge, and when the fused substance is generated, it shifts from an appropriate classification point. Moreover, even if the flow rate is adjusted by suction decompression, it is difficult to obtain the required particle size distribution of the powder, and the classification efficiency is drastically reduced. Furthermore, it is difficult to obtain a high-quality product because a fused material is mixed in the classified powder.

In the classifying device of the present invention, the classifying edge blocks 24 and 25 are moved when the classifying edges 17 and 18 are moved.
By moving the particles simultaneously along the direction of the classification edge in the flow direction of the particle flow flying along the Coanda block 26, and then as the suction pressure reducing means, the discharge conduits 11a, 12a, 1
By adjusting the flow rate of the suction flow through 3a, the flying speed of the particles can be increased and the dispersion of the powder in the classification region can be further improved, so that the classification yield is improved and the fusion to the tip of the classification edge is improved. Adhesion is prevented or suppressed, and highly accurate classification is possible.

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 μm.
It is more preferable when classifying powder having a particle diameter of m or less, and particularly preferable when classifying powder having a weight average particle diameter of 8 μm or less.

The toner particles constituting the toner contain at least a non-magnetic colorant or / and a magnetic material and a binder resin, and the binder resin has a glass transition point of 45 to 80 ° C. (more preferably 50). To 75 ° C.) is preferable from the viewpoint of heat fixing property and blocking resistance. Preferred binder resins include styrene-acrylic copolymers, styrene-methacrylic copolymers, polyester resins or mixtures thereof.

When the colorant is a non-magnetic colorant such as carbon black and phthalocyanine, the colorant is 0.5 to 20 parts by weight (preferably 1 part by weight) per 100 parts by weight of the binder resin.
(About 15 parts by weight) is preferable.

When the coloring agent is a magnetic substance such as magnetite or magnetic ferrite, the magnetic substance is preferably added in an amount of 20 to 200 parts by weight (preferably 30 to 150 parts by weight) per 100 parts by weight of the binder resin.

The colored resin particles to be toner particles may be prepared by a melt kneading-pulverization method, or a suspension polymerization method or an emulsion polymerization method.

In the classifying device of the present invention, a stepping motor is used as the moving means for moving the direction of the classification edge and the edge tip position, and a potentiometer 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 means of and to automate the flow rate adjustment, because the desired classification point can be obtained more accurately in a short time.

Next, a specific example in which the product (toner) is obtained by actually classifying the colored resin powder for toner production will be described.

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, glass transition point about 55 ° C.) 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 to 1 mm or less with a hammer mill to obtain a coarsely crushed material. The coarsely pulverized product was finely pulverized by a collision type air flow pulverizer to obtain a colored resin powder having a weight average particle diameter of 7.0 μm. The true density of the colored resin powder was 1.73 g / cm ³ .

In the classification system shown in FIG. 6, the obtained colored resin powder is fed through the feeder 2 to the vibration feeder 3
1 and FIG. 5 for classifying into three types of a coarse powder group, a medium powder group and a fine powder group by utilizing the Coanda effect at a rate of 35.0 kg / h through the raw material supply pipe 16. It was introduced into the multi-division classifier 1.

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 injection nozzle 31 attached to the raw material supply pipe 16 Utilizing air compression from.

In order to change the shape of the classification area, the respective set distances shown in FIG. 5 are set to L ₀ = 6 mm (height diameter of the raw material supply nozzle discharge port 16a) L ₁ = 32 mm (side surface of the classification edge 17 and the Coanda Distance from side surface of block 26) L ₂ = 33 mm (side surface of classification edge 17 and classification edge 1)
8 of the distance between the side) L ₃ = 39mm (the distance between the classification distance between side surfaces and the side wall 23 of the edge 18) L ₄ = 14mm (side surface of the tip and the Coanda block 26 of the classifying edge 17) L ₅ = 33mm (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 fox of Coanda block 26) And classified.

The introduced colored resin powder was classified in an instant of 0.1 seconds or less. The classified medium powder group has a weight average particle size of 6.85 μm (contains 24% by number of particles having a particle size of 4.0 μm or less and 1.0 volume% of particles having a particle size of 10.08 μm or more). It is possible to obtain a medium powder group having a sharp distribution with a classification yield (ratio of the finally obtained medium powder to the total amount of the pulverized raw materials charged) of 89%. Had excellent performance for toner. This classified coarse powder group was recirculated to the crushing step.

The true density of the colored resin powder was measured using the following measuring device. As the measuring device, Micromeritics Accupic 1330 (manufactured by Shimadzu Corporation) is used.
The true density was determined by weighing 5 g of toner finely pulverized powder.

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.

As a measuring device, a Coulter counter T
A-II type or Coulter Multisizer II (manufactured by Coulter) was used. As the electrolytic solution, about 1% NaCl aqueous solution was prepared using first-grade sodium chloride. For example, I
SOTON R-II (manufactured by Coulter Scientific Japan) can be used. As a measuring method, 0.1 to 5 ml of a surface active agent (preferably alkylbenzene sulfonate) as a dispersant was added to 100 to 150 ml of the electrolytic solution, and 2 to 20 mg of a measurement sample was further added. The electrolytic solution in which the sample is suspended is about 1 to 3 with an ultrasonic disperser.
Dispersion treatment is performed for a minute, and the measurement device uses a 100 μm aperture as an aperture to measure the toner volume,
The number was measured and the volume distribution and number distribution were calculated. Then, the weight-based weight average particle diameter obtained from the toner volume distribution was obtained.

Examples 2 to 4 Table 1 was prepared using the pulverization raw materials shown in Table 1 obtained by pulverizing the same coarsely pulverized product for toner production as in Example 1 with a collision type air flow pulverizer.
Classification was performed using the same equipment system except that the set distance in the classification area shown in was used.

As shown in Tables 2 and 3, it was possible to efficiently obtain a medium powder group having a sharp distribution, and the obtained medium powder group had excellent performance as a toner. .

[0070]

[Table 1]

[0071]

[Table 2]

[0072]

[Table 3]

Examples 5 and 6 Unsaturated polyester resin (glass transition point: about 55 ° C.)
100 parts by weight Copper phthalocyanine pigment 4.5 parts by weight (CI Pi
gment Blue 15) -Charge control agent 4.0 parts by weight

A Henschel mixer (Example 1)
Same as above) and then set the temperature to 100 ° C. 2
The kneading was performed using a shaft kneader (the same as in Example 1). The obtained kneaded material was cooled and coarsely pulverized to 1 mm or less with a hammer mill to obtain a coarsely crushed material. The coarsely pulverized product was finely pulverized by a collision type air flow pulverizer to obtain a colored resin powder (Example 5) having a weight average particle diameter of 6.6 μm. The true density of the obtained colored resin powder is 1.08.
It was g / cm ³ .

Using this colored resin powder, classification was carried out in the same apparatus system as in Example 1 except that the classification conditions shown in Table 4 were used.

The above-mentioned coarsely pulverized product was finely pulverized by a collision type air flow pulverizer to obtain a colored resin powder (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, it is possible to efficiently obtain a medium powder group having a sharp distribution, and the obtained medium powder group has excellent performance for toner. Was there.

[0078]

[Table 4]

[0079]

[Table 5]

[0080]

[Table 6]

Comparative Examples 1 to 3 Using the same toner raw material as in Example 1, the coarsely pulverized material was finely pulverized by a collision type air flow pulverizer, and the weight of the pulverized raw material (Comparative Example 1) and the weight average particle diameter of 6.9 μm were compared. A ground material (Comparative Example 2) having an average particle size of 5.5 μm was obtained.

The toner raw material was changed to that of Example 5 to obtain a pulverized raw material (Comparative Example 3) having a weight average particle diameter of 6.5 μm.

The classification was carried out according to the flow chart of FIG. 9, and the multi-division classifiers used were those shown in FIGS. 7 and 8.

The classification conditions are as shown in Table 7,
The particle size distribution and the like of the medium powder group obtained by classification were as shown in Tables 8 to 10.

[0085]

[Table 7]

[0086]

[Table 8]

[0087]

[Table 9]

[0088]

[Table 10]

[0089]

As described above, according to the airflow type classification apparatus of the present invention, fusion at the tip of the classification edge can be prevented satisfactorily, and turbulence of the classification airflow at the tip of the classification edge can be improved. It is possible to obtain an accurate classification point according to the specific gravity of various powders and classification airflow conditions, and it is possible to improve the classification yield without shifting the classification point even during continuous operation of the device.

Further, L of the airflow classifier used in the present invention
By adjusting ₀ , L ₁ , L ₂ , L ₃ , L ₄ , L ₅ and L ₅ , fusion at the tip of the classification edge can be satisfactorily prevented,
In addition, turbulent flow of the classification airflow at the tip of the classification edge can be satisfactorily prevented, and accurate classification points can be obtained according to the specific gravity of various powders and the classification airflow conditions. The classification yield can be improved without deviation. In particular,
This is effective when classifying colored resin powder for toner having a weight average particle diameter of 10 μm or less.

[Brief description of drawings]

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

FIG. 2 is a three-dimensional view of an airflow classifier according to the present invention.

FIG. 3 is a three-dimensional view of an airflow classifier according to the present invention.

FIG. 4 is a diagram showing a main part of FIG.

5 is a diagram showing a main part of FIG.

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

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

FIG. 8 is a three-dimensional view of a conventional airflow classifier.

FIG. 9 is an explanatory 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 Inlet pipe 16 Raw material supply nozzle 17 1st classification edge 18 2nd classification edge 19 Air-intake edge 20 1st gas introduction adjustment means 21 2nd gas introduction adjustment means 22, 23 Side wall 24 1st classification edge block 25 2nd 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

Front page continuation (72) Inventor Yoko Goka 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Masayoshi Kato 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (36)

[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. An airflow classifying device for classifying into groups, wherein the classifying edge block having the classifying edge can change its installation position so that the shape of the classifying area can be changed. 2. The airflow classification device according to claim 1, wherein the installation position of the classification edge is movable along with a change in the installation position of the classification edge block. 3. 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. 4. The airflow classification device according to claim 1, wherein the classification edge block can move its installation position in a horizontal direction or a substantially horizontal direction. 5. The airflow classification device according to claim 1, wherein the classification edge can move its installation position in a horizontal direction or a substantially horizontal direction. 6. The airflow type classification device according to claim 1, wherein the classification area is formed by a Coanda block and a classification edge. 7. The airflow type classification apparatus according to claim 1, further comprising a classification area formed between the classification edge and another classification edge. 8. The airflow classification device according to claim 1, wherein a classification region is further formed between the classification edge and the side wall. 9. The airflow type classification according to claim 1, wherein each of the plurality of classification edges is provided in the classification edge block, and the classification edge is movable along with the movement of the classification edge block. apparatus. 10. Two classification edges are provided, and a classification area for classifying a fine powder group having a predetermined particle size or less is formed between the Coanda block and the first classification edge.
A classification area for classifying a medium powder group having a predetermined particle size is formed between the classifying edge and the second classifying edge, and a coarse powder group having a predetermined particle size or more is formed between the second classifying edge and the side wall. The airflow classification device according to claim 1, wherein a classification region for classification is formed. 11. 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. 12. A plurality of classification edge blocks are provided, and each classification edge block is provided with a classification edge so that a tip of the classification edge can rotate. Airflow type classifier. 13. The Coanda block is installed in contact with the raw material supply nozzle, and the powder discharged from the raw material supply nozzle is provided between the Coanda block and the side wall except for a particle group having a predetermined particle size and a particle size other than the predetermined particle size. A classification chamber for classifying particles by the Coanda effect is provided in the particle group.
2. An airflow classifier according to any one of 2. 14. The airflow according to claim 1, wherein the installation position of the classification edge is regulated by a positioning member so as to be movable in the same direction or substantially the same direction as the moving direction of the classification edge block. Type classifier. 15. Each classifying edge is rotatably supported by a shaft, and the distance between the first shaft supporting the first classifying edge and the Coanda block can be changed. It is possible to change the distance between the second shaft supporting the second classification edge and the first shaft, and it is possible to change the distance between the second shaft and the side wall. The airflow classification device according to any one of claims 1 to 14. 16. A colored resin powder having a true density of 0.3 to 1.4 g / cm ³ is supplied to a raw material supply nozzle, and the colored resin powder is conveyed by an air stream flowing in the raw material supply nozzle to form a Coanda block. The colored resin powder is introduced into a classifying chamber formed between the side wall and the side wall, and the colored resin powder is classified by the Coanda effect, so that at least the coarse powder group, the intermediate powder group, and the fine powder group are separated into a plurality of powders. A method for producing a toner from a group of intermediate powders separated by a classifying edge, wherein the classifying edge blocks each having a classifying edge and whose position can be changed are installed under the following condition L ₀ > 0. , L ₁ > 0, L ₂ > 0, L ₃ > 0 L ₀ <L
₁ + L ₂ <nL ₃ [where L ₀ is the height diameter of the discharge port of the raw material supply nozzle (m
m) indicates, L ₁ represents the distance between the side surface of the first classifying edge for demarcating medium powder group and the fine powder group and the binary, with the side surface of the Coanda block that faces to (mm), L ₂ is the distance (m between the side surface of the first classification edge and the side surface of the second classification edge for fractionating into the coarse powder group and the medium powder group).
m), L ₃ represents the distance (mm) between the side surface of the second classification edge and the side surface of the side wall facing the second classification edge, and n is a real number of 1 or more] A method for producing a toner, comprising: 17. The fine powder group is separated into a classification area formed between the first classification edge and the Coanda block,
The medium powder group is divided into classification regions formed between the first classification edge and the second classification edge, and the coarse powder group is classified into the classification region formed between the second classification edge and the side wall. The method for producing a toner according to claim 16, wherein the toner is separated into areas. 18. The first classification edge is rotatably supported by a first shaft, and the second classification edge is rotatably supported by a second shaft, the first shaft and the Coanda. 18. The method for producing a toner according to claim 16, wherein the particle size of the fine powder group is changed by changing the distance between the block and the block. 19. The method for producing a toner according to claim 16, wherein the particle diameter of the medium powder group is changed by changing the distance between the first axis and the second axis. 20. The method for producing a toner according to claim 16, wherein the particle size of the coarse powder group is changed by changing the distance between the second axis and the side wall. 21. L ₀ is 2 to 10 mm and L ₁ is 1.
0 to 150 mm, L ₂ is 10 to 150 mm, L ₃ is 10 to 150 mm, L ₄ is ₅ to 70 m
m, L ₅ is 15 to 160 mm, and L ₆ is 10
The method for producing a toner according to any one of claims 16 to 20, wherein the toner has a thickness of -100 mm and n is 0.5-3. 22. The colored resin powder is colored resin particles containing a non-magnetic coloring agent and a binder resin.
22. The method for producing a toner according to any one of 21 to 21. 23. The method for producing a toner according to claim 22, wherein the colorant is contained in an amount of 0.5 to 20 parts by weight per 100 parts by weight of the binder resin. 24. The binder resin has a glass transition point of 45 to 80.
The method for producing a toner according to claim 22, which has a temperature of 0 ° C. 25. The binder resin according to claim 22, wherein the binder resin is formed of a material selected from the group consisting of a styrene-acrylic copolymer, a styrene-methacrylic copolymer, a polyester resin and a mixture thereof. The method for producing a toner according to claim 1. 26. The coloring resin powder contains 50% by number or more of particles having a particle diameter of 20 μm or less.
5. The method for producing a toner according to any one of 1. 27. A colored resin powder having a true density of more than 1.4 g / cm ³ is supplied to a raw material supply nozzle, and the colored resin powder is conveyed by an air stream flowing in the raw material supply nozzle, and a coanda block and a side wall are formed. The colored resin powder is supplied to the classifying chamber formed between them, and the colored resin powder is classified by the Coanda effect, and separated into at least a coarse powder group, a medium powder group and a fine powder group by a plurality of classification edges. And a method for producing toner from the separated medium powder group, in which the installation positions of the classification edge blocks each of which has a classification edge and whose position can be changed are set to the following conditions L ₀ > 0, L ₁ >. 0, L ₂ > 0, L ₃ > 0 L ₀ <L
₃ <L ₁ + L ₂ [where L ₀ is the height diameter of the discharge port of the raw material supply nozzle (m
m) indicates, L ₁ represents the distance between the side surface of the first classifying edge for demarcating medium powder group and the fine powder group and the binary, with the side surface of the Coanda block that faces to (mm), L ₂ is the distance (m between the side surface of the first classification edge and the side surface of the second classification edge for fractionating into the coarse powder group and the medium powder group).
m), and L ₃ represents a distance (mm) between the side surface of the second classification edge and the side surface of the side wall facing the second classification edge]. 28. The fine powder group is separated into a classification area formed between the first classification edge and the Coanda block,
The medium powder group is divided into classification regions formed between the first classification edge and the second classification edge, and the coarse powder group is classified into the classification region formed between the second classification edge and the side wall. 28. The method for producing a toner according to claim 27, wherein the toner is separated into areas. 29. The first classifying edge is rotatably supported by a first shaft, and the second classifying edge is rotatably supported by a second shaft, the first shaft and the Coanda. 29. The method for producing a toner according to claim 27, wherein the particle size of the fine powder group is changed by changing the distance between the block and the block. 30. The method for producing a toner according to claim 27, wherein the particle diameter of the medium powder group is changed by changing the distance between the first axis and the second axis. 31. L ₀ is 2 to 10 mm and L ₁ is 1.
0 to 150 mm, L ₂ is 10 to 150 mm, L ₃ is 10 to 150 mm, L ₄ is ₅ to 70 m
m, L ₅ is 15 to 160 mm, and L ₆
Is 10 to 100 mm, and the method for producing a toner according to claim 27. 32. The colored resin powder is magnetic resin particles containing a magnetic material and a binder resin.
5. The method for producing a toner according to any one of 1. 33. The method for producing a toner according to claim 32, wherein the magnetic substance is contained in an amount of 20 to 200 parts by weight per 100 parts by weight of the binder resin. 34. The binder resin has a glass transition point of 45 to 80.
The method for producing a toner according to claim 32 or 33, which has a temperature of 0 ° C. 35. The binder resin according to claim 32, wherein the binder resin is formed of a material selected from the group consisting of a styrene-acrylic copolymer, a styrene-methacrylic copolymer, a polyester resin, and a mixture thereof. The method for producing a toner according to claim 1. 36. The colored resin powder contains 50 number% or more of particles having a particle diameter of 20 μm or less.
5. The method for producing a toner according to any one of 1.