JP3347551B2 - Airflow classifier and method for producing toner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic classifier for classifying powders utilizing the Coanda effect. In particular, in order to efficiently classify a powder containing 50% by number or more of particles having a particle size of 20 μm or less, the present invention conveys the powder in an air stream, and carries out the Coanda effect and the particle size of each particle in the powder. The present invention relates to an airflow classifier for classifying particles having a predetermined particle size based on differences in inertial force, centrifugal force, and the like according to the diameter.

[0002] Further, the present invention relates to a method for producing a toner using an airflow classifier for classifying a colored resin powder utilizing the Coanda effect. Particularly, 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 in an air stream and carries the Coanda effect, The present invention relates to a method for producing a toner for developing an electrostatic image by classifying a group of colored resin particles having a predetermined particle size based on a difference in inertial force, centrifugal force or the like according to the particle size of each particle.

[0003]

2. Description of the Related Art Various methods for classifying powder have been proposed for airflow classifiers. 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. Lof is a classifier that uses inertial force.
fier. F. and K. Mally: Symp on
Powder technology classifiers exemplified by Powder Techn D2 (1981) and commercialized by Nippon Steel Mining Co., Ltd., and Okuda. S. and Yasukun
i. J. Proc. Inter. Symposium
on Powder Techn '81, 771 (1
981) has been proposed as an inertial force classifier capable of classifying in the fine powder region.

These air-flow classifiers are shown in FIGS.
As shown in the figure, the raw material supply nozzle 16 having an opening in the classification area of the classification chamber injects the powder raw material into the classification area together with the airflow at high speed, and has a Coanda block 26 in the classification chamber. A classifying edge having a thinned tip is separated into a coarse powder group, a medium powder group, and a fine powder group by centrifugal force of a curved airflow flowing along the Coanda block 26 by introducing an airflow intersecting with the jetting airflow. The coarse powder group, the medium powder group, and the fine powder group are separated by 117 and the classification edge 118.

However, when the raw material powder is introduced into the raw material supply nozzle 16 from the raw material supply port 40 by the conventional classifier 101 as shown in FIG. Having a tendency to flow along the inner wall surface of the inner passage. At this time, when the powder raw material is introduced from above in the raw material supply nozzle 16, the powder raw material is classified by gravity, and a large amount of light fine powder is contained in the flow above the passage,
A large amount of heavy coarse powder is likely to be contained in the flow below the passage.
As shown in FIG. 13, coarse particles in the lower flow disturb the trajectory of the fine particles in the upper flow, which limits the improvement in classification accuracy. Further, in the classification of a powder having a large number of coarse particles having a particle size of 20 μm or more, the accuracy tends to decrease.

In particular, as one of the steps for manufacturing a toner used in an image forming apparatus such as a copying machine and a printer,
When the raw material powder is classified, it is required that the classified particles have a sharp particle size distribution, and it is important that the cost is low, the efficiency is high, and the classification accuracy is good.

In view of the above, there is a demand for a method for producing a toner by classifying a colored resin powder such as a toner stably, efficiently and accurately.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an airflow classifier and a method for producing a toner which have solved the above-mentioned problems.

An object of the present invention is to provide an airflow classifier capable of efficiently classifying powder having a highly precise particle size distribution and a method for producing a toner using the same.

An object of the present invention is to provide an air-flow classifier capable of performing stable classification without causing fusing in a classification region and causing a change in a classification point in the apparatus.

It is a further object of the present invention to provide an airflow classifier capable of greatly changing the classification point.

A further object of the present invention is to provide an airflow classifier capable of changing the classification point in a short time.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a toner which enables more accurate classification by setting an accurate classification point and can efficiently produce a toner having a fine particle size distribution. .

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a toner which does not easily cause fusing or the like and does not cause a change in a classification point in the apparatus, and can perform a stable classification.

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

It is a further object of the present invention to provide a method for producing a toner in which the classification point can be changed in a short time.

[0017]

SUMMARY OF THE INVENTION The present invention provides an air flow classifier for classifying raw material powder utilizing the Coanda effect, wherein an opening for discharging the raw material powder into a classification area of a classification chamber is provided. A raw material supply nozzle provided at a tip is provided, a raw material supply port for supplying raw material powder into the raw material supply nozzle is provided at an upper part of a rear portion of the nozzle, and a position of a leading end opening of the raw material supply nozzle is provided. The present invention relates to an airflow classifier characterized in that a Coanda block is provided at a higher level than the above.

Further, according to the present invention, the colored resin powder is introduced into an airflow classifier and classified into at least a fine powder group, a medium powder group and a coarse powder group, and toner is classified from the classified medium powder group. a method of manufacturing, the airflow classifier is, there is carried out the classification of the colored resin powder by utilizing the Coanda effect, the colored resin
A raw material supply nozzle having an opening at the tip for ejecting the powder into the classification area of the classification chamber is provided, and a raw material supply port for supplying the colored resin powder into the raw material supply nozzle is provided in the nozzle. The present invention relates to a method for producing a toner, characterized in that a Coanda block is provided at an upper portion of a rear portion and a Coanda block is provided at a position higher than a position of a leading end opening of a material supply nozzle. Further, the present invention provides a method of introducing a colored resin powder into an airflow classifier, classifying the colored resin powder into at least a fine powder group, a medium powder group and a coarse powder group, and producing a toner from the classified medium powder group. The air-flow classifier comprises a classifying chamber, a raw material supply nozzle for introducing a colored resin powder into a classifying region of the classifying chamber, and the introduced colored resin powder at least in a fine powder group by a Coanda effect. It has at least a Coanda block for classifying into a powder group and a coarse powder group, and the raw material supply nozzle has a raw material supply port for introducing a colored resin powder into the raw material supply nozzle, In the raw material supply nozzle, the colored resin powder is accelerated by an air current and introduced into the classification area from the distal end opening of the raw material supply nozzle, and the Coanda block is located at a position higher than the position of the distal end opening of the raw material supply nozzle. That they have been set up The method for producing a toner according to symptoms.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the accompanying drawings, and the present invention will be described in detail.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As an example of an airflow classifier used in the present invention, an apparatus of the type shown in FIG. 1 (cross-sectional view) and FIG.

In the air classifier according to the present invention, when the raw material powder 41 is supplied from the raw material supply port 40 provided above the rear part of the raw material supply nozzle 16, gravity in the raw material supply nozzle 16 is caused by the Coanda effect. Classification occurs, and the fine powder group flows upward and the coarse powder group flows downward, but the Coanda block 26 is provided above the position of the opening provided at the end of the raw material supply nozzle 16 on the classification chamber side. The flow of the upper flow and the lower flow is not obstructed, and the coarse powder flow (lower flow) is caused by the Coanda effect.
Can be classified from the outer circumference, and the fine powder flow (upstream flow) can be classified from the inner circumference. For this reason, the classification area is expanded as compared with the conventional airflow type classifier as shown in FIG. 11, the classification point can be largely changed, and the classification is performed without generating the turbulence of the airflow near the end of the classification edge. Points can be adjusted with high accuracy. As a result, according to the present invention, it is possible to satisfactorily prevent the fusion at the tip of the classification edge, and also properly prevent the turbulence of the classification airflow at the tip of the classification edge, and perform specific gravity and classification of various powders An accurate classification point can be obtained according to the airflow conditions, and the classification point does not shift even when the apparatus is continuously operated, and the classification yield can be improved. It is particularly effective when classifying fine powder having a particle size of 10 μm or less.

1 and 2, side walls 22 and 23 are shown.
Forms part of a classifying chamber, the classifying edge blocks 24 and 25 have classifying edges 17 and 18. The classification edges 17 and 18 are rotatable about the axes 17a and 18a, and the classification edges can be rotated to change the classification edge tip positions. Each of the classifying edge blocks 24 and 25 can be slid right and left, and accordingly, the respective knife-edge classifying edges 17 and 18 also slide right and left. By the classification edges 17 and 18, the classification zone of the classification chamber 32 is divided into three.

A raw material supply nozzle 16 having a raw material supply port 40 for introducing the raw material powder 41 above and an opening in the classification chamber 32 is provided above the side wall 22, and an upper tangent to the raw material supply nozzle 16 is provided. A Coanda block 26 that draws an arc with respect to the extension direction is provided. The lower block 27 of the classifying chamber 32 is provided with a knife-edge type inlet edge 19 below the classifying chamber 32, and further provided with air inlet pipes 14 and 15 opening to the classifying chamber 32 below the classifying chamber 32. . The inlet pipes 14 and 15 are provided with a first gas introduction adjusting means 20, a second gas introduction adjusting means 21, such as a damper, and a static pressure gauge 28 and a static pressure gauge 29.

Classification edges 17, 18 and inlet edge 19
Is adjusted according to the type and desired particle size of the powder raw material as the raw material to be classified.

At the upper part of the classifying chamber 32, there are provided outlets 11, 12, and 13 which open into the classifying chamber corresponding to the respective separating areas, and the outlets 11, 12, and 13 are provided with communicating means such as pipes. Are connected, and each may be provided with an opening / closing means such as a valve means.

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

The classification operation in the multi-division classification region configured as described above is performed, for example, as follows. Outlet 1
The pressure in the classifying chamber is reduced through at least one of 1, 12, and 13, and the raw material supply nozzle 16 having an opening in the classifying chamber.
The powder raw material 41 is blown into the classifying chamber through the raw material supply nozzle 16 at a flow velocity of preferably 50 to 300 m / sec by a gas flow flowing at a high speed in the inner passage.

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

In the classification of the powder raw material according to the present embodiment,
The classification point is the classification edge 1 for the left end portion of the Coanda block 26 at the position where the powder raw material jumps into the classification chamber 32.
It is mainly determined by the edge tip positions of 7 and 18.
Further, the classification point is affected by the flow rate of the classification airflow, the speed of the powder material being ejected from the material supply nozzle 16, and the like.

In the air classifier of the present invention, the raw material powder 41 is instantaneously introduced from the raw material supply nozzle 16 into the classification room, classified, and discharged out of the classifier system. When the powder raw material introduced into the classification chamber is introduced from the raw material supply nozzle 16 into the classification chamber, it is important that the trajectories of the individual particles fly with propulsion without being disturbed. The particle flow flowing in the passage of the raw material supply nozzle 16 forms an upper flow and a lower flow, and when the powder raw material 41 is introduced from the upper part (the raw material supply port 40 in FIG. 1), the upper flow of the raw material supply nozzle 16 Since a large amount of light fine powder is contained and a large amount of heavy coarse powder is contained in the lower stream, when the powder stream is introduced into the classifying chamber 32 having the Coanda block 26 above the opening at the tip of the raw material supply nozzle 16, Since the particle trajectory is dispersed according to the size of the particle without disturbing the trajectory of the particle, a particle flow is formed,
The classification edge can be moved in the direction along the streamline, and then the edge tip position of the classification edge can be fixed and set to a predetermined classification point. When the classification edges 17 and 18 move, the edges move in the flow direction of the particle stream flying along the Coanda block 26 by simultaneous movement with the classification edge blocks 24 and 25.

More specifically, referring to FIG. 3, the tip of the classification edge 17 and the side surface of the Coanda block 26 are centered on, for example, a position O in the Coanda block 26 located above the tip opening 16a of the raw material supply nozzle 16. Distance L ₄
The distance L ₁ between the side surface of the classification edge 17 and the side surface of the Coanda block 26 moves the classification edge block 24 right and left along the positioning member 34 by moving the classification edge block 24 right and left along the positioning member 33. It can be adjusted by rotating the tip of the classification edge 17 about the shaft 17a.

[0032] Similarly, the side surface of the classifying edge 18 of the tip and the Coanda distance between the wall surface of the block 26 L ₅ and classifying the distance between the side edges 17 and the side surface of the classifying edge 18 L ₂ or classifying edge 18 of the side surface and the side wall 23 distance L ₃ between, by moving the classifying edge block 25 right and left along the locating member 35 to move the classifying edge 18 right and left along the locating member 36, a further axis 18a of the tip of the classifying edge 18 It can be adjusted by turning around the center. The Coanda block 26 and the classification edges 17 and 18 are installed above the tip opening 16a of the raw material supply nozzle 16, and with the change of the installation position of the classification edge block 24 and / or the classification edge block 25, the classification of the classification chamber is performed. The shape of the zone changes, and the classification point can be adjusted easily and significantly.

Therefore, turbulence of the flow due to the tip of the classification edge can be effectively prevented, and the discharge conduits 11a, 12a and 1
By adjusting the flow rate of the suction flow from the intake pipes 14 and 15 due to the reduced pressure via 3a, the flying speed of the particles is increased to improve the dispersion of the powder raw material in the classification region, and the good dust concentration is obtained even at a high dust concentration. Classification accuracy can be obtained, and not only a reduction in the yield of the particle group to be a product can be prevented, but also better classification accuracy and an improvement in yield can be achieved at the same dust concentration.

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

In FIG. 3, a straight line drawn on the upper surface of the material supply nozzle 16 from the foremost portion of the Coanda block and a perpendicular line drawn perpendicularly to the straight line from the tip of the material supply nozzle intersect with each other. Let the point be the intersection O. Let R be the length from the position where the straight line connecting the intersection O and the tip of the inlet edge 19 and the surface of the Coanda block 26 to the intersection O.

The above set distance is appropriately determined according to the characteristics of the powder raw material and the like, but the true density of the powder raw material is 0.3 to 1.
At 4 g / cm ³ , for example, in the case of a non-magnetic colored resin powder, L ₀ <L ₁ + L ₂ <nL ₃ (n ≧ 1: real number) When the true density of the powder raw material exceeds 1.4 g / cm ³ For example, in the case of a magnetic colored resin powder, it is preferable to satisfy L ₀ <L ₃ <L ₁ + L ₂ . When this condition is satisfied, a product (medium powder) having a sharper distribution can be efficiently obtained.

Usually, the air-flow classifier used in the present invention is used by connecting mutual devices by a communication means such as a pipe, and is incorporated in an apparatus system. A preferred example of such a device system is shown in FIG. The integrated device system shown in FIG. 4 includes a three-divider classifier 1 (the classifier shown in FIGS. 1 and 2), a quantitative feeder 2, a vibration feeder 3, a collecting cyclone 4, a collecting cyclone 5, and a collecting cyclone 6. Are connected by communication means.

In this apparatus system, the powder raw material is
The material is fed into the fixed-quantity feeder 2 by an appropriate means, and then supplied to the material feed nozzle 16 through the vibrating feeder 3.
It is introduced into the split classifier 1. At the time of introduction, high-speed gas ejected from the injection nozzle 31
It is preferable to introduce the powder raw material into the three-division classifier 1 at a flow rate of 0 to 300 m / sec. The size of the classification chamber of the three-division classifier 1 is usually [10 to 50 cm] × [10 to 5 cm].
0 cm], the powder can be classified into three or more particle groups in an instant of 0.1 to 0.01 seconds or less. Then, the particles are classified into large particles (coarse particles), intermediate particles, and small particles by the three-division classifier 1. After that, the large particles are discharged to discharge conduit 1
After passing through 1a, it is sent to the collecting cyclone 6 and collected.
The intermediate particles are discharged out of the system via the discharge conduit 12a and collected by the collection cyclone 5. The small particles are discharged out of the system via the discharge conduit 13a and collected by the collection cyclone 4. The collection cyclones 4, 5, and 6 can also function as suction decompression means for sucking and introducing the powder raw material into the classification chamber via the raw material supply nozzle 16.

The air-flow classifier of the present invention is particularly effective when classifying toner or colored resin powder for toner used in an image forming method by electrophotography. In particular, low melting point,
This is effective when classifying a toner composition having a binder resin having 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 material is apt to be generated at the tip of the classification edge, and if a fused material is generated, it deviates from an appropriate classification point. Even if the flow rate is adjusted by suction pressure reduction,
It is difficult to obtain the required particle size distribution of the powder, and the classification efficiency is reduced. Further, a fused product is mixed in the classified powder, and it is difficult to obtain a high quality product.

In the classifier of the present invention, when the classification edges 17 and 18 are moved, the classification edges are oriented in the flow direction of the particle stream flying along the Coanda block 26 by the simultaneous movement with the classification edge blocks 24 and 25. Then, the discharge conduits 11a, 12a, 13 are used as suction pressure reducing means.
By controlling the flow rate of the suction flow through a, 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 further improved, and the melting to the tip of the classification edge is improved. This has the effect of preventing or suppressing wear for a long period of time and performing highly accurate classification.

The effect of the classifier of the present invention is more remarkable as the particle diameter of the powder is smaller, and particularly, the weight average diameter is 10 μm.
When classifying the following powders, it is possible to obtain a classified product having a sharp particle size distribution, and it is also possible to obtain a classified product having a sharp particle size distribution from powder having a weight average diameter of 6 μm or less. It is.

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

FIG. 5 shows a specific example of an airflow classifier capable of adjusting the height L ₀ of the opening at the tip of the material supply nozzle 16.

FIG. 5 is an overall sectional view of a specific example of the airflow classifier of the present invention, and FIG. 6 is an enlarged view of the opening of the tip end of the material supply nozzle 16 of FIG. 5 and 6,
The lower side walls 22 and 23 form a part of the classification chamber 32, and the upper classification edge blocks 24 and 25 include:
Classification edges 17 and 18 are provided. The classification edges 17 and 18 are centered on axes 17a and 18a,
The classification edges 17 and 18 can be rotated to freely change the tip position of the classification edge. By such classification edges 17 and 18, the classification area of the classification chamber 32 is divided into three as shown in FIG.

A raw material supply nozzle 16 having an opening to a classifying chamber 32 is provided at an upper portion of the side wall 22. A Coanda block having an arc extending in the direction in which the upper tangent extends is provided above the raw material supply nozzle 16. 26 are installed. Further, the lower block 27 at the lower part of the classifying chamber 32 is provided with a knife-edge type inlet edge 19 toward the upper part of the classifying chamber 32. The knife-edge-type inlet edge 19 is, like the classification edges 17 and 18, also provided with a shaft 19a.
, And is rotatable about the
9 can be freely changed.

As shown in FIG. 5, on the upper surface of the classifying chamber 32, outlets 11, 12, and 13 which are open to the classifying chamber are provided corresponding to the respective classification areas.

The side wall 22 extends along the positioning member 42,
The lower end of the raw material supply nozzle 16 is provided with the shafts 43 and 44 so that the lower end of the raw material supply nozzle 16 smoothly moves up and down, thereby changing the height L ₀ of the opening at the tip end of the raw material supply nozzle 16. be able to.

In FIG. 7, a classification edge 17 is formed around a point O in the Coanda block 26 corresponding to the upper part of the opening 16a on the classification chamber side at the tip of the raw material supply nozzle 16.
The distance L ₄ between the tip of and the side of the Coanda block 26 is
It can be adjusted by rotating the tip of the classification edge 17 around the shaft 17a. Similarly, the distance L ₅ between the side surface of the tip and the Coanda block 26 of the classifying edge 18, can be adjusted by rotating the tip of the classifying edge 18 around the shaft 18a. A Coanda block 26, classification edges 17 and 18 are installed above the tip opening 16a of the raw material supply nozzle 16,
By appropriately changing the height L ₀ of the material supply nozzle opening according to the physical properties of the powder material, the classification area of the classification room is expanded, and the classification point can be adjusted more easily and significantly. Becomes

The air-flow classifier of the present invention is particularly effective when classifying toner particles used for image formation by electrophotography. It is particularly effective when classifying toner particles containing a binder resin having a low melting point, a low softening point and a low glass transition point.

When toner particles are subjected to a conventional classifier using such a binder resin having physical properties, fused matter is hardly generated particularly at the opening of the material supply nozzle.

FIG. 8 shows another example of the airflow classifier of the present invention. 8, the classification edge blocks 24 and 25 and the side wall 22 are fixed.

Next, a production example in which a product (toner) is obtained by performing fine pulverization and classification using a crushed product for toner production will be described.

Production Example 1 100 parts by weight of styrene-butyl acrylate-divinylbenzene copolymer (binder resin) [monomer polymerization weight ratio: 80.0 / 19.0 / 1.0, weight average molecular weight (Mw): 350,000 100 parts by weight of magnetic iron oxide [average particle size 0.18 μm] (colorant and magnetic substance) 2 parts by weight of nigrosine (charge control agent) 4 parts by weight of low molecular weight ethylene-propylene copolymer (offset inhibitor)

The above materials were mixed with a Henschel mixer (FM-7).
The mixture was well mixed with a No. 5 model (manufactured by Mitsui Miike Kakoki Co., Ltd.) and then kneaded with a twin-screw kneader (PCM-30, manufactured by Ikegai Iron Works Co., Ltd.) set at a temperature of 150 ° C. The obtained kneaded material was cooled and coarsely pulverized with a hammer mill to 1 mm or less to obtain a coarsely crushed material for toner production. The crushed material is finely pulverized by a collision type air current pulverizer to obtain a finely pulverized powder having a weight average particle size of 6.7 μm.
The true density was 1.73 g / cm ³ .

The obtained finely pulverized product is supplied through the fixed-quantity feeder 2 through the vibrating feeder 3 and the raw material supply pipe 16 to the fine pulverized product.
In order to classify into coarse powder, medium powder and fine powder by utilizing the Coanda effect at a rate of 5.0 kg / h, it was introduced into a multi-segment classifier 1 shown in FIG.

At the time of introduction, the suction force derived from the pressure reduction in the system by the suction pressure reduction of the collecting 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. Compressed air was used.

The shape of the classification area is changed, and each set distance is set to L ₀ = 6 mm (height diameter of the tip opening 16a of the material supply nozzle) L ₁ = 34 mm (the side of the classification edge 17 and the side of the Coanda block 26) L ₂ = 33 mm (side of classification edge 17 and classification edge 1)
L ₃ = 37 mm (distance between the side surface of the classification edge 18 and the side surface of the side wall 23) L ₄ = 15 mm (distance between the tip of the classification edge 17 and the side surface of the Coanda block 26) L ₅ = 35 mm was performed (classification distance between the tip and the co sides of the under block 26 of the edge 18) L ₆ = 25 mm (the distance between the side surface of the tip and the Coanda block 26 of inlet air edge 19) classified in the R = 14 mm.

The introduced finely pulverized raw material was classified instantaneously in 0.1 seconds or less. The classified medium powder has a sharp weight average particle diameter of 6.9 μm (containing 22% by number of particles having a particle diameter of 4.0 μm or less and 1.0% by volume of particles having a particle diameter of 10.08 μm or more). Powder having a good distribution can be obtained with a classification yield (the ratio of the final powder obtained to the total amount of the supplied pulverized raw materials to the total amount of the pulverized raw materials) of 92%, and has excellent performance for toner. I was The classified coarse powder was circulated again to the grinding step.

The true density of the finely pulverized toner powder was measured using the following measuring apparatus in the present invention. As a measuring device, Micrometrics Acupic 1330 (manufactured by Shimadzu Corporation) was used, and 5 g of finely pulverized toner powder was measured to determine the true density.

The particle size distribution of the toner can be measured by various methods. In the present invention, the measurement was performed using the following measuring apparatus.

As a measuring device, Coulter Counter T
Type A-II or Coulter Multisizer II (manufactured by Coulter Inc.) was used. As an electrolytic solution, an approximately 1% NaCl aqueous solution is prepared using primary sodium chloride. For example, I
SOTON R-II (manufactured by Coulter Scientific Japan) can be used. As a measurement method, 0.1 to 5 ml of a surfactant (preferably an alkylbenzene sulfonate) is added as a dispersant to 100 to 150 ml of the aqueous electrolyte solution, and 2 to 20 mg of a measurement sample is further added. The electrolyte in which the sample was suspended was treated with an ultrasonic
For a minute, and the measuring device uses a 100 μm aperture as an aperture to obtain the toner volume and
The number was measured to calculate a volume distribution and a number distribution. Then, a weight-based weight average particle diameter determined from the volume distribution according to the present invention was determined.

Production Examples 2 to 4 Using the pulverized raw materials shown in Table 1 obtained by pulverizing a roughly crushed product for toner production similar to that of Production Example 1 with an impinging airflow pulverizer, the following Table 1 was used.
The classification was performed using the same apparatus system except that the set distance of the classification area shown in FIG.

As shown in Tables 2 and 3, a medium powder having a sharp distribution can be efficiently obtained.
It had excellent performance for toner.

[0065]

[Table 1]

[0066]

[Table 2]

[0067]

[Table 3]

Production Examples 5 and 6 : 100 parts by weight of unsaturated polyester resin (binder resin) 4.5 parts by weight of copper phthalocyanine pigment (colorant) (CI Pigment Blue 15) Charge control agent 4.0 Parts by weight

The above materials were mixed with a Henschel mixer (Production Example 1).
) And then kneaded with a twin-screw kneader (same as in Production Example 1) set at a temperature of 100 ° C. The obtained kneaded material was cooled and coarsely pulverized with a hammer mill to 1 mm or less to obtain a coarsely crushed material for toner production. The crushed material is finely pulverized with a collision type air current pulverizer to obtain a pulverized raw material (Production Example 5) having a weight average particle size of 6.5 μm and a true density of 1.08 g / cm ^3.
Met.

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

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

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

[0073]

[Table 4]

[0074]

[Table 5]

[0075]

[Table 6]

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

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

Classification was carried out in accordance with the flow chart of FIG. 11, and the multi-segment classifiers shown in FIGS. 9 and 10 were used.

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

[0080]

[Table 7]

[0081]

[Table 8]

[0082]

[Table 9]

[0083]

[Table 10]

Production Example 7 100 parts by weight of styrene-butyl acrylate-divinylbenzene copolymer (binder resin) [monomer polymerization weight ratio: 80.0 / 19.0 / 1.0, weight average molecular weight (Mw): 350,000 100 parts by weight of magnetic iron oxide [average particle size 0.18 μm] (colorant and magnetic substance) 2 parts by weight of nigrosine (charge control agent) 4 parts by weight of low molecular weight ethylene-propylene copolymer (offset inhibitor)

The above materials were mixed with a Henschel mixer (FM-7).
The mixture was well mixed with a No. 5 model (manufactured by Mitsui Miike Kakoki Co., Ltd.) and then kneaded with a twin-screw kneader (PCM-30, manufactured by Ikegai Iron Works Co., Ltd.) set at a temperature of 150 ° C. The obtained kneaded material was cooled and coarsely pulverized with a hammer mill to 1 mm or less to obtain a coarsely crushed material for toner production. The crushed material is finely pulverized by a collision type air current pulverizer to obtain a finely pulverized powder having a weight average particle size of 7.0 μm.
The true density was 1.5 g / cm ³ .

The obtained pulverized raw material is supplied to the vibrating feeder 3 and the raw material supply pipe 16 through the quantitative feeder 2 and then to the pulverized raw material.
In order to classify into coarse powder, medium powder and fine powder at a rate of 5.0 kg / h utilizing the Coanda effect, the powder was introduced into a multi-segment classifier 1 shown in FIG.

At the time of introduction, the suction force derived from the pressure reduction in the system by the suction pressure reduction of the collecting 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. Compressed air was used. The height L ₀ of the material supply nozzle opening was 8 mm. As a result, the finely pulverized raw material introduced from the raw material supply nozzle 16 was classified instantaneously in 0.1 second or less.

The intermediate powder obtained by the classification as described above has a weight average particle size of 6.8 μm and a particle size of 4.0 μm.
The following particles are contained in 24% by number, and the particle size is 10.08μ.
It had a sharp particle size distribution containing 1.0% by volume of particles of m or more. A high yield of a classification yield of 80% was obtained, and the intermediate powder had excellent performance as a toner material. After the operation, the tip opening of the raw material supply nozzle 16 was observed, and no fusion was observed.

Production Example 8 The same coarsely crushed product for toner production as in Production Example 7 was pulverized with a collision type air current pulverizer to obtain a pulverized raw material having a weight average particle size of 6.4 μm. Using the pulverized raw material, classification was performed by the same classification system as in Production Example 7. 31.0 kg / h of pulverized raw material
Of the particles having a weight average particle size of 5.9 μm, containing 30% by number of particles having a particle size of 4.0 μm or less, and reducing the particles having a particle size of 10.08 μm or more to 0%. A medium powder having a sharp particle size distribution containing 0.2% by volume was obtained with a high classification yield of 76%. The medium powder had excellent performance as a toner material. After the operation, the tip opening of the raw material supply nozzle 16 was observed, and no fusion was observed. The classified coarse powder was returned to the pulverization step, which is a stage before the classification step, and circulated again.

Production Example 9 A coarsely crushed product for toner production similar to that of Production Example 7 was pulverized by a collision type air current pulverizer to obtain a pulverized raw material having a weight average particle size of 5.5 μm. Using the pulverized raw material, classification was performed by the same classification system as in Production Example 7.

By introducing the pulverized raw material into the multi-splitting classifier at a rate of 25.0 kg / h, particles having a weight average particle size of 5.2 μm and a particle size of 3.17 μm or less can be reduced to 30 μm.
1. Particles containing several% and having a particle size of 8.00 μm or more
A medium powder having a sharp particle size distribution containing 6% by volume was obtained with a high classification yield of 72%. The medium powder is
It had excellent performance as a toner material. After the operation, the tip opening of the raw material supply nozzle 16 was observed, and no fusion was observed. The classified coarse powder was returned to the pulverization step, which is a stage before the classification step, and circulated again.

Production Example 10 The same coarsely crushed product for toner production as in Production Example 7 was pulverized by a collision type air current pulverizer to obtain a pulverized raw material having a weight average particle size of 5.5 μm. Using the pulverized raw material, classification was performed by the same classification system as in Production Example 7.

The pulverized raw material was introduced at a rate of 25.0 kg / h into a multi-segmentation classifier so that the weight average particle size was 5.
A medium powder having a sharp particle size distribution of 4 μm, containing 20% by number of particles having a particle size of 3.17 μm or less and 1.9% by volume of particles having a particle size of 8.00 μm or more has a classification yield of A high yield of 70% was obtained. The medium powder had excellent performance as a material for a toner. After the operation, the tip opening of the raw material supply nozzle 16 was observed, and no fusion was observed. The classified coarse powder was returned to the pulverization step, which is a stage before the classification step, and circulated again.

Production Example 11 100 parts by weight of unsaturated polyester resin 4.5 parts by weight of copper phthalocyanine pigment (CI Pigment Blue 15) 4.0 parts by weight of charge control agent

The above materials were mixed with a Henschel mixer (FM-
75, manufactured by Mitsui Miike Chemical Industry Co., Ltd.)
A twin-screw kneader (PCM-30 type, set at a temperature of 100 ° C)
(Ikegai Iron Works Co., Ltd.). The obtained kneaded material was cooled and coarsely pulverized with a hammer mill to 1 mm or less to obtain a coarsely crushed material for toner production. The crushed material is finely pulverized by a collision type air current pulverizer, and has a weight average particle size of 6.5 μm and a true density of 1.1 g /
cm ³ of ground material was obtained.

Next, the pulverized raw material obtained as described above is passed through the vibratory feeder 3 through the quantitative feeder 2 and through the raw material supply nozzle 16 at a rate of 31.0 kg / h.
It was introduced into the multi-segmentation classifier 1 shown in FIG. 5 and classified into three types of coarse powder, medium powder and fine powder utilizing the Coanda effect.

At the time of introduction, the outlets 11, 12, 13
A suction force derived from the pressure reduction in the system by the suction pressure reduction of the collection cyclones 4, 5, and 6 communicating with the sampler, and the compressed air from the injection nozzle 31 attached to the material supply nozzle 16 were used. The finely pulverized raw material introduced from the raw material supply nozzle 16 was classified instantaneously in 0.1 seconds or less.

The medium powder obtained by the classification has a weight average particle diameter of 5.9 μm, contains 24% by number of particles having a particle diameter of 4.0 μm or less, and has a particle diameter of 10.08 μm or more. The particles had a sharp particle size distribution containing 1.0% by volume of particles, and could be obtained with a high classification yield of 80%. The medium powder had excellent performance as a toner material. After the operation, the tip opening of the raw material supply nozzle 16 was observed, and no fusion was observed. The classified coarse powder was returned to the pulverization step, which is a stage before the classification step, and circulated again.

[0099]

As described above, according to the airflow classifier of the present invention, powder can be classified with high accuracy by the Coanda effect of the Coanda block without disturbing the trajectory of the raw material powder discharged from the raw material supply nozzle. Can be classified.

[Brief description of the drawings]

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

FIG. 2 is a three-dimensional view of the airflow classifier shown in FIG.

FIG. 3 is a diagram showing a main part of FIG. 1;

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

FIG. 5 is a schematic sectional view of another embodiment of the airflow classifier of the present invention.

FIG. 6 is a partially enlarged view of a front end opening of a raw material supply nozzle of the airflow classifier of the present invention.

FIG. 7 is a diagram showing a main part of FIG. 5;

FIG. 8 is a schematic sectional view of another embodiment of the airflow classifier of the present invention.

FIG. 9 is a schematic sectional view of a conventional airflow classifier.

FIG. 10 is a three-dimensional view of a conventional airflow classifier.

FIG. 11 is an explanatory diagram showing an example of a conventional classification process.

FIG. 12 is an enlarged view near a raw material supply port at a rear end of the raw material supply nozzle.

FIG. 13 is an enlarged view of a tip portion of a raw material supply nozzle.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1,101 Air flow classifier 2 Quantitative feeder 3 Vibration feeder 4,5,6 Collection cyclone 11,12,13 Discharge port 11a, 12a, 13a Discharge conduit 14,15 Intake pipe 16 Raw material supply nozzle 17,18 Classification edge DESCRIPTION OF SYMBOLS 19 Inlet edge 20 1st gas introduction adjusting means 21 2nd gas introduction adjusting means 22, 23 Side wall 24, 25 Classification edge block 26 Coanda block 27 Upper block 28, 29 Static pressure gauge 30a, 30b, 30c Solid particle scattering direction 31 Injection Air introduction pipe 32 Classification chamber 33, 34, 35, 36 Positioning member 40 Raw material supply port

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

Claims (25)

(57) [Claims] 1. A gas flow classifier for classifying raw material powder utilizing the Coanda effect, wherein a raw material supply nozzle having an opening at a tip for jetting the raw material powder into a classification area of a classification chamber is provided. A raw material supply port for supplying raw material powder into the raw material supply nozzle is provided at an upper portion of a rear portion of the nozzle, and a Coanda block is provided at a position higher than a position of a tip opening of the raw material supply nozzle. An airflow classifier characterized by being used. 2. A raw material supply nozzle is disposed in a horizontal direction or a substantially horizontal direction, and a fine powder group in the raw material powder introduced into the raw material supply nozzle is introduced above the raw material supply nozzle by the Coanda effect. The airflow classifier according to claim 1, wherein a raw material supply port is provided so as to perform the operation. 3. The fine powder discharge port for discharging the fine powder group in the raw material powder classified by the Coanda effect is provided at a position higher than the position of the tip opening of the raw material supply nozzle. Or the airflow classifier according to 2. 4. The air classifier according to claim 1, wherein a classification area is formed by at least a Coanda block and a classification edge. 5. The airflow classifier according to claim 4, wherein the classification edge is provided at a position higher than the position of the leading end opening of the raw material supply nozzle. 6. The airflow classifier according to claim 4, wherein a plurality of classification edges are provided. 7. A classification region is formed by at least a Coanda block and a plurality of classification edges, and the raw material powder supplied from the raw material supply nozzle is divided into at least a coarse powder group, a medium powder group, and a fine powder group by the Coanda effect. The classification edge block which is classified and has the classification edge can change its installation position so that the shape of the classification area can be changed.
The air-flow classifier described in 1. 8. The airflow classifier according to claim 7, wherein the installation position of the classification edge is movable with a change in the installation position of the classification edge block. 9. The airflow classifier according to claim 7, wherein a classification edge is provided in the classification edge block so that a tip of the classification edge can rotate. 10. The installation position of the classification edge block can be changed in a horizontal direction or a substantially horizontal direction.
An airflow classifier according to any one of claims 1 to 9. 11. The installation position of the classification edge can be changed in a horizontal direction or a substantially horizontal direction.
The air classifier according to any one of the above. 12. A raw material supply nozzle is disposed in a horizontal direction or a substantially horizontal direction, and when a raw material powder supplied from a raw material supply port is introduced into the raw material supply nozzle , the raw material supply nozzle is provided with a Coanda effect . The airflow classifier according to any one of claims 7 to 11, wherein a raw material supply port is provided so that the fine powder is introduced above the unit. 13. A fine powder discharge port for discharging a fine powder group in the raw material powder classified by the Coanda effect is provided at a position higher than a position of an end opening of a raw material supply nozzle. 13. The air-flow classifier according to any one of 12 above. 14. A medium powder discharge port for discharging a group of medium powders in the raw material powder classified by the Coanda effect is provided at a position higher than the position of the tip opening of the raw material supply nozzle. Item 14. An airflow classifier according to any one of Items 7 to 13. 15. A coarse powder discharge port for discharging a coarse powder group in the raw material powder classified by the Coanda effect is provided at a position higher than a position of a tip opening of a raw material supply nozzle. The airflow classifier according to any one of items 7 to 14. 16. The classification edge is set at a position higher than the position of the tip opening of the raw material supply nozzle.
5. The airflow classifier according to any one of 5. 17. The airflow classifier according to claim 1, wherein the height of the opening at the tip of the material supply nozzle is changeable. 18. A method in which a colored resin powder is introduced into an airflow classifier and classified into at least a fine powder group, a medium powder group and a coarse powder group, and a toner is produced from the classified medium powder group. The air-flow classifier uses a Coanda effect to color resin powder.
A performs the classification of the body, the colored resin powder and the raw material supply nozzle is provided with a tip opening for ejecting the classification region of the classifying chamber, wear raw material supply nozzle
A toner supply port for supplying a color resin powder is provided at an upper portion of a rear portion of the nozzle, and a Coanda block is provided at a position higher than a position of a leading end opening of the material supply nozzle. Manufacturing method. 19. The air flow classifier according to claim 2, wherein
19. The method for producing a toner according to claim 18, wherein the classifier is a classifier described in any one of the above. 20. A method in which a colored resin powder is introduced into an airflow classifier and classified into at least a fine powder group, a medium powder group and a coarse powder group, and a toner is produced from the classified medium powder group. The air-flow classifier includes a classifying chamber, a material supply nozzle for introducing a colored resin powder into a classifying area of the classifying chamber, and at least a fine powder group and a medium powder by the Coanda effect. The raw material supply nozzle has at least a Coanda block for classifying into a body group and a coarse powder group, and the raw material supply nozzle has a raw material supply port for introducing a colored resin powder into the raw material supply nozzle. In the raw material supply nozzle, the colored resin powder is accelerated by the airflow and introduced into the classification area from the front end opening of the raw material supply nozzle, and the Coanda block is positioned higher than the position of the front end opening of the raw material supply nozzle. That is installed in A method for producing a toner. 21. A classifying area is formed by at least a Coanda block and a plurality of classifying edges, and a classifying edge block having the classifying edge is changed in its installation position so that the shape of the classifying area can be changed. , each of the set distance _{L 0> 0, L 1>} 0, L 2> 0, L 3> 0 ( where, L _0; and medium powder group; the distal opening of the material feed nozzle height diameter L ₁ Distance between the side of the classification edge to be divided into the fine powder group and the side of the Coanda block facing the same L ₂ ; the side of the classification edge to be divided into the medium powder group and the fine powder group, and the coarse powder Distance between the side of the classification edge that separates the group and the medium powder group L ₃ ; The side of the classification edge that separates the coarse powder group and the medium powder group from the side of the side wall that faces the classification edge When the true density of the colored resin powder is 0.3 to 1.4 g / cm ³ , L ₀ <L ₁ + L ₂ <nL ₃ (n ≧ 1: real number), and when the true density of the colored resin powder exceeds 1.4 g / cm ³ ,
L ₀ <L ₃ <method for producing a toner according to claim 20 for L ₁ + L classified under _two. 22. L ₀ is ₂ to 10 mm, and L ₁ is 10
Is a ~150mm, L ₂ is 10~150mm,
L ₃ is 10 to 150 mm, L ₄ is 5~70mm, L ₅ is 15~160mm and L ₆ is 10 to 10
22. The method for producing a toner according to claim 21, wherein the thickness is 0 mm. 23. The method for producing a toner according to claim 21, wherein n is 0.5 to 3. 24. The colored resin powder has a true density of 0.3 to 1.
22. The method for producing a toner according to claim 20, which is a nonmagnetic colored resin powder of 4 g / cm ³ . 25. The colored resin powder has a true density of 1.4 g / c.
A magnetic colored resin powder having a particle size exceeding m ^3.
2. The method for producing a toner according to item 1.