JP4291685B2 - Toner production method - Google Patents

Description

  The present invention relates to a fluidized bed pulverizer for pulverizing and classifying a powder material, particularly a powder material used for producing an electrophotographic toner, to produce a fine powder.

A conventionally known fluidized bed type pulverizer is used as an apparatus for producing a desired micron-order fine powder such as an electrophotographic toner, and at least a plurality of pulverizers are provided inside a cylindrical side wall. Generally, a nozzle, a crushing chamber, and a rotating classification rotor (also referred to as a rotary classifier) provided above the crushing chamber are arranged.
In order to produce a fine powder using the fluidized bed type pulverizer, a powder material to be pulverized, and in the case of the toner, a kneaded material made of a material such as a resin and a colorant constituting the toner is roughly pulverized. Thus, a toner powder material (referred to as toner raw material) prepared in advance is prepared in advance.
Next, after supplying the powder material into the pulverization chamber, the powder material is accelerated by a jet stream formed by injecting compressed air from a plurality of pulverization nozzles, and the powder materials collide with each other and pulverize. Then, the pulverized powder material is guided to a classifying rotor that is rotated by the generated rising airflow and classified by the classifying rotor, and the powder material having a desired particle size or less is discharged through the inside of the classifying rotor to be a product. The powder material (coarse powder) that is not collected in the desired particle size is extruded to the outside of the classifying rotor by centrifugal force, returned to the grinding chamber along the side wall, and repeatedly crushed. A pulverizing and classifying operation using a pulverizing apparatus is performed.

FIG. 1 is a schematic cross-sectional view showing an example of a conventional fluidized bed pulverizer.
In FIG. 1, the entire pulverizing apparatus main body is composed of a substantially cylindrical casing, wherein reference numeral (1) denotes a pulverizing chamber, (2) denotes a supply pipe to which a powder material is supplied, and (3) denotes a pulverizing chamber (1 (4) is a rotor for classifying the pulverized powder material (classification rotor), (5) is pulverized and classified to a desired particle size and completed. Exhaust pipes for discharging the powder together with air are shown.
In the conventional fluidized bed type pulverizing apparatus of FIG. 1, first, a pulverizing chamber (1) is filled with a certain amount of powder material, and then a plurality of pulverizing nozzles (3) installed facing each other. Compressed air discharged from the cylinder collides near the exit extension line of each of the opposing pulverizing nozzles (3), that is, near the central axis of the pulverizing chamber (1). The material also collides near the central axis of the crushing chamber ( 1 ) and receives a crushing action.
On the other hand, the pulverized powder material is sent to the exhaust pipe (5) by suction with a suction device (not shown) such as a suction fan communicating with the exhaust pipe (5). At this time, since the rotor (4) installed at the upper part of the crushing chamber (1) is rotating, the powder material pulverized to a desired particle size is discharged through the exhaust pipe (5) and collected as a product. However, the powder material (coarse powder) larger than the desired particle size is guided to the outside of the classification rotor (4) by the centrifugal force of the classification rotor (4) and guided downward along the wall surface of the grinding chamber (1). Then, it will be crushed again.

Further, when the powder material pulverized to a desired particle size is discharged from the exhaust pipe (5) and recovered as a product, the amount of the powder material inside the pulverization chamber (1) decreases, so the supply pipe ( The powder material can be newly supplied from 2), and the continuous pulverization can be performed by always setting the amount of the powder material in the pulverization chamber (1) to be constant.
However, in the conventional fluidized bed type pulverizer, in order to obtain a desired particle size, it is necessary to repeatedly pulverize in the pulverization chamber. However, a certain amount of powder material filled in the pulverization chamber. Is accelerated and collides oppositely by being guided by jet jets ejected from a plurality of pulverization nozzles installed in the surroundings, so when volume pulverization occurs, the ratio of surface pulverization increases and excessive pulverization that generates ultrafine powder occurs. This is one of the causes of reducing the grinding efficiency or production capacity.

In the case of using a fluidized bed type pulverizer, there is a problem that coarse powder and ultrafine powder are produced and pulverized or the production efficiency is lowered. Next, technology that has been proposed for the purpose of solving this problem from the past. Will be described.
For example, for the purpose of efficiently obtaining a pulverized product having a desired particle size, the upper surface of the powder material deposited on the bottom plate provided in the pulverization chamber in the fluidized bed type pulverizer is always held at the position where the air flow is ejected from the pulverization nozzle. As described above, a mechanism for installing a bottom plate position adjusting device that moves the bottom plate up and down has been proposed (see, for example, Patent Document 1).
However, according to the fluidized bed crusher disclosed in Patent Document 1, although the upper surface of the powder material deposited on the bottom plate can be held at the airflow ejection position of the nozzle, compared with the conventional fluidized bed crusher. Thus, it is considered difficult to efficiently obtain a pulverized product having a desired particle size.
That is, in the fluidized bed pulverization apparatus disclosed in Patent Document 1, as a method for holding the upper surface of the powder material deposited on the apparatus bottom plate, for example, the weight of the powder material deposited on the apparatus bottom plate is measured. Although the upper surface of the powder material to be deposited is maintained by maintaining a constant weight and this can be expected to improve the powder efficiency to some extent, the pulverizing action itself received by the powder material is different from that of a conventional fluidized bed type pulverizer. However, it is considered that the repeated pulverization inside the pulverization chamber necessary for obtaining a desired particle size is insufficient, which is one of the causes for reducing the pulverization efficiency.

In addition, as another device for improving the pulverization efficiency, the collision member is installed so that the center thereof is located on the central axis of the pulverization chamber, and the high-speed gas is jetted vertically together with the powder material to the collision member. Thus, a technology has been proposed in which a powder material is pulverized by colliding with a collision member to obtain a pulverized product having a desired particle size (see, for example, Patent Document 2).
However, in the fluidized bed pulverizer disclosed in Patent Document 2, the pulverization nozzle pressure must be increased when the high-speed gas injected from the nozzle and the powder material in the pulverization chamber collide with the collision member. There is a problem.
The reason for this is that in the conventional fluidized bed type pulverization apparatus previously shown in FIG. 1, the high-speed gas is injected from a plurality of nozzles arranged opposite to each other, so that the powder materials are accelerated together with the high-speed gas. While colliding with speed and receiving a crushing action, according to the apparatus of Patent Document 2, the relative speed between the powder materials is not accelerated together with the high-speed gas, and in order to obtain a higher crushing effect, The pressure of the pulverizing nozzle must be increased to cause the powder material to collide with the collision member at a higher speed, and the object to be crushed collides with the collision member by the high-speed gas injected from the nozzle, but the desired particle size This is considered to be one of the causes for reducing the pulverization efficiency because it cannot be repeatedly pulverized in the pulverization chamber to obtain the slag.

Moreover, although the technique of patent document 1 and patent document 2 is related to the technique around a crushing nozzle, about the device for suppressing ultrafine powder is not described at all.
Furthermore, along with the recent improvement in image quality by electrophotography, there is a high demand for electrophotographic toners having a small particle size or a small quantity and a wide variety of products, and there is a demand for rapid and efficient toner production. As for the layer-type pulverizer, it is desired that when the pulverization and classification operation is switched to a powder of a different type, the switching can be easily performed in a shorter time than the conventional apparatus.

JP-A-11-226443 JP 2000-5621 A

In view of the above circumstances, a first problem of the present invention is a fluidized bed type pulverizing apparatus capable of efficiently pulverizing a powder material, particularly a powder material used for producing an electrophotographic toner, and preventing over-pulverization. It is to provide a pulverization / classification method using the same.
In addition, the second problem of the present invention is that it is possible to achieve improved collision pulverization efficiency in the pulverization chamber of the fluidized bed pulverizer and to obtain particles having a desired particle size by pulverization with high efficiency. It is to provide a fluidized bed type pulverizing apparatus and a pulverizing / classifying method using the same.
Furthermore, the third object of the present invention is to provide a fluidized bed type pulverization apparatus capable of shortening the kind change time and a pulverization / classification method using the same.

Upper Symbol challenge consists (1) "substantially cylindrical housing of the present invention, the grinding chamber, a plurality of grinding nozzles for injecting compressed air, said grinding chamber classifying rotor provided above, before being injected Compressed air sprayed from a plurality of pulverization nozzles in the pulverization chamber provided with at least a heating means for heating the compressed air and a means for adjusting the temperature of the side wall and bottom of the pulverization chamber. The powder material is pulverized by using a fluidized bed type pulverizing apparatus that pulverizes the pulverized powder material into the classification rotor rotating from the pulverization chamber and centrifugally classifies the powder material into fine powder and coarse powder. In the pulverization chamber to which the material is supplied, compressed air is sprayed from a plurality of pulverization nozzles to pulverize the powder material, and the pulverized powder material flows into the classification rotor rotating from the pulverization chamber to make fine powder. And a method of manufacturing toner that is centrifugally classified into coarse powder The powder material is a toner raw material obtained by coarsely pulverizing a kneaded material comprising at least a resin and a colorant constituting electrophotographic toner, and has a dew point of −50 ° C. to −10 ° C. in compressed air. The toner is heated to 0 ° C. or more and 50 ° C. or less, and the temperature of the side wall of the pulverization chamber is adjusted to 0 to 40 ° C. ”, (2)“ The temperature of the bottom of the pulverization chamber is The method for producing a toner according to (1) above, wherein the pressure is from -5 to 30 ° C., and (3) “the pressure of the compressed air ejected from the pulverizing nozzle is set to 0.2 to 1.0 MPa. (4) “Adjusting the peripheral speed of the classifying rotor to 20 to 50 m / s,” wherein the toner production method according to the above item (1) or (2) is characterized. The toner according to any one of (1) to (3) (Method), (5) The above-mentioned items (1) to (5), wherein a fluidized bed type pulverizer provided with a classification rotor having a plurality of blades whose surfaces are treated with a conductive release agent is used. (4) The method for producing a toner according to any one of Items 4) and (6), wherein the fluidized bed pulverizing apparatus having a pulverizing chamber whose inner wall is treated with a conductive release agent is used. (1) Item (1), wherein the method for producing a toner according to any one of Items (5) to (7) is a fluidized bed type pulverizer having 2 to 8 pulverizing nozzles. Item 1 to Item (6), wherein the method for producing a toner according to any one of Items (6) to (6) is used, and (8) a fluidized bed type pulverizer having 1 to 5 classification rotors is used. Thru | or the manufacturing method of the toner in any one of (7) ", (9)" Two crushing noses installed correspondingly (1) to (8), wherein a fluidized bed pulverizer is used such that the distance L between them and the height H of the pulverization chamber satisfy a relationship of 2L ≦ H ≦ 5L. The method for producing a toner according to any one of items 1) and (10), wherein the fluidized bed type pulverizer provided with a spacer for adjusting the height H of the pulverization chamber is used. The toner production method described in 1) is achieved.

  When the powder material, especially the powder material used for producing the electrophotographic toner is pulverized using the fluidized bed pulverizer of the present invention, the compressed air injected from the pulverization nozzles is heated. Therefore, it is difficult to cause excessive pulverization of the powder material, the generation amount of fine powder is reduced, it can be pulverized with high efficiency, and the centrifugal classification of fine powder and coarse powder by the classification rotor can be performed efficiently, Productivity of powder products, particularly toner for electrophotography, can be improved.

Hereinafter, the fluidized bed type pulverizing apparatus and the pulverizing / classifying method using the same will be described in detail.
The fluidized bed type pulverization apparatus of the present invention comprises a substantially cylindrical casing as a whole, and is filled with a plurality of pulverization nozzles, powder material supplied from the outside, and compressed air from the pulverization nozzles. At least a pulverizing chamber in which the powder raw material is pulverized and a classification rotor are provided. In the pulverizing chamber, the pulverized material is pulverized into fine powder and coarse powder, and further, the pulverized fine powder and coarse powder are centrifuged and classified with a classification rotor. In that respect, it is the same as the conventional fluidized bed type pulverizer as shown in FIG.
FIG. 2 is a schematic cross-sectional view showing an example of the fluidized bed type pulverizer of the present invention.
The fluidized bed type pulverizer shown in FIG. 2 has a pulverizer main body consisting of a substantially cylindrical casing, a pulverization chamber (1), a supply pipe (2) for supplying powder raw materials, and a pulverization chamber (1). A plurality of pulverizing nozzles (3) for sending compressed air fed to the slab, a classification rotor (4) for classifying the pulverized powder raw material (also referred to as pulverized product), and a pulverized product that has been pulverized and classified to a desired particle size Is provided with at least an exhaust pipe (5) that discharges the air together with air, but is characterized in that it is provided with heating means (7) for compressed air. .
If a heating means (7) for compressed air is provided in a conventional fluidized bed grinder, the fluidized bed grinder of the present invention can be applied. In the conventional fluidized bed type pulverizer, as a product manufactured by Hosokawa Micron Co., Ltd., the product name is Counterjet Mill AFG, and a toner of type 100 to 630 AFG is used for production of toner such as electrophotography. As a product manufactured by Mitsui Mining Co., Ltd., there is a trade name “Condax Mill CGS”, model CGS32-100 can be used for the production of toner such as electrophotography, and Kurimoto Steel Works Co., Ltd. The product manufactured by the company is the cross jet mill KJ, which can be used to produce toner such as electrophotography.

This heating means provided in the fluidized bed type pulverizer is for suppressing the generation of ultrafine powder due to excessive pulverization of the powder raw material. For this reason, the heating means does not necessarily have to be operated at all times. You may make it operate.
Since air normally has a characteristic of generating heat when compressed, conventionally, temperature control of compressed air used for toner pulverization or the like is generally performed through a cooler. However, the compressed air can be used as it is depending on the pulverization condition without operating the heating means.
Controlling the temperature of the compressed air is important for reducing over-pulverization and suppressing the generation of ultrafine powder. If the temperature is too low, over-pulverization of the powder raw material tends to occur, whereas if the temperature is high, the powder raw material is The surface of the material is warmed and softened, making it difficult to grind. It is preferable to do this.
Further, the heating means is not particularly limited. For example, a method of heating a surface with an electric heater through multiple pipes like a radiator, a method of using a compressor without passing through a cooler, etc. Is used.

Compressed air injected from each pulverizing nozzle (3) is sent through a feed pipe to the pulverizing nozzle (3), and a heating means (7) for the compressed air is provided on the upstream side of the feed pipe and has a dew point. The compressed air supplied at a temperature of −10 ° C. to −50 ° C. is heated, and the compressed air thus heated is sprayed from each of the crushing nozzles (3) to be used for crushing the powder raw material. Examples of the heating means include an electric heater, a direct heating method using steam or a method using a heating medium, but are not particularly limited.
That is, as the compressed air heating means, specifically, for example, a spiral pipe is provided in the pipeline connecting the compressor and the pulverizer, and the compressed air passing through the interior is supplied from the surface of the spiral pipe to the electric heater band, Heat replacement using a heat medium such as steam or oil. When the temperature adjusting means is an electric heater, current adjustment is performed. When the temperature is adjusted, the pressure is adjusted. In the case of steam, the oil or water is circulated by passing cooling water or chiller water through a water cooling jacket. Adjustments are made at.
Grinding is to break up solid particles by mechanical action such as impact, compression, shear, friction, etc., and to subdivide them without changing their material structure. The heated powder raw material surface has higher elasticity than the inside, and as a result, even if the powder raw materials collide with each other, so-called over-grinding is reduced, and the amount of fine powder generated is reduced. It is considered that it is suppressed and can be classified into fine powder and coarse powder by centrifugation.

In particular, a viewpoint that a large amount of powder raw material can be efficiently pulverized by adjusting the heating of the compressed air so that the jet jet temperature ejected from the pulverizing nozzle, that is, the temperature of the compressed air is in the range of 0 to 50 ° C. Is desirable.
When the jet jet temperature is less than 0 ° C., the surface of the powder raw material is cooled and easily plasticized, and surface pulverization is likely to occur. If the jet jet temperature exceeds 50 ° C., the surface of the powder raw material becomes easy to soften or melt, and the pulverizability is deteriorated. Further, the kneaded material in the powder raw material is deteriorated, and the quality may be reduced. It is not preferable.
If compressed air is discharged without temperature control, the temperature is less than 0 ° C. due to adiabatic expansion, which is not preferable.

FIG. 3 is a schematic cross-sectional view showing another example of the fluidized bed pulverizer of the present invention.
In order to maintain the elastic state of the powder raw material surface obtained by the heating means as described above, the fluidized bed type pulverizer shown in FIG. 3 has a temperature of the side wall (8) of the pulverization chamber (1) of 0 to 0. It is characterized by the provision of a mechanism that can be adjusted within the range of 40 ° C. By such a mechanism, the amount of ultrafine powder generated by surface grinding can be further suppressed, and more efficient grinding and classification can be achieved. This is desirable because it can improve the productivity of the powder.
As the side wall cooling means (10) of the pulverization chamber, for example, a method of circulating the chiller water or the cooling tower water by using a jacket around the periphery is used.
When the temperature of the side wall of the pulverization chamber is less than 0 ° C., the heating effect by the jet jet is lowered, the surface of the powder material is cooled and plasticized easily, and surface pulverization easily occurs. When the temperature of the side wall of the crushing chamber exceeds 40 ° C., the cooling rate of the impact-pulverized powder raw material is lowered, the surface is softened or melted easily, and is fixed or fused to the surface of the crushing chamber. In addition, the kneading material in the powder raw material may deteriorate and the quality may deteriorate.

Further, in FIG. 3, the heated jet jet ejected from the pulverization nozzle (3) is convected into the pulverization chamber (1) of the fluidized bed pulverizer of the present invention. As a result, the bottom (9 ) May be susceptible to heat storage and adversely affect the pulverization. As a method of avoiding this heat storage, the bottom (9) of the pulverization chamber located below the pulverization nozzle (5) is set to −5 to 30 ° C. If the temperature is adjusted within the range, the elasticity of the powder raw material surface to be crushed can be maintained, the amount of fine powder generated by the surface pulverization can be suppressed, and the classification rotor can be centrifugally classified into fine powder and coarse powder. It is desirable that it can be efficiently pulverized, a large amount of powder raw material can be efficiently pulverized, and productivity can be improved.
As a cooling means (11) for the bottom (9) of the crushing chamber, there is a method of circulating the chiller water or the cooling tower water by using a jacket around it, but is not limited to the above.
When the temperature of the bottom (9) of the pulverization chamber is less than −5 ° C., the superheat effect of the jet jet is lowered, the surface of the powder material is cooled and plasticized easily, and surface pulverization easily occurs.
When the temperature of the bottom (9) of the pulverization chamber exceeds 30 ° C., the cooling rate of the collisionally pulverized powder raw material tends to decrease. As a result, the surface is easily softened or melted, and the bottom of the pulverization chamber It is not desirable because it is fixed or fused to the surface of the material, and the pulverizability is deteriorated, and the kneaded material in the powder material is deteriorated to deteriorate the quality.
When the temperature of the compressed air rises, the crushed material is likely to be fixed. Therefore, the temperature control of the side wall of the pulverization chamber or the bottom of the pulverization chamber described above is performed by, for example, covering the wall or bottom with a spiral pipe and cooling the inside. Water or chiller water is allowed to pass through and cooling is performed by controlling the amount of circulating water or cooling water, and a water cooling cooling unit, a chiller unit, or the like is used. The cooling temperature is appropriately selected depending on the temperature of the compressed air.
That is, in the fluidized bed pulverizer of the present invention, the compressed air is heated to prevent over-pulverization, but the compressed air can be cooled as necessary to prevent the pulverized material from sticking. it can.

Furthermore, in the fluidized bed type pulverizing apparatus of the present invention, if pulverization and classification are performed for a long time, unground and pulverized pulverized matter may adhere to the classification rotor and reduce the efficiency of pulverization and classification. As a solution to this problem, the surface of the plurality of blades constituting the classifying rotor (4) is a conductive mold release agent, in particular, conductive Teflon (registered trademark) or nickel-Teflon (registered trademark) composite plating considering wear resistance. It is desirable to perform surface treatment such as.
Examples of nickel Teflon (registered trademark) composite plating include electroless nickel Teflon (registered trademark) composite plating manufactured by Nippon Kanisen Co., Ltd., and Koda Skate Teflon (registered trademark) manufactured by Kodama Co., Ltd. manufactured by Nippon Kanisen Co., Ltd. ) Plating, electroless Teflon (registered trademark) plating manufactured by Hazuki Kogyo Co., Ltd., or Teflon (registered trademark) electroless nickel manufactured by Sanwa Plating Industry Co., Ltd. can be used.
In the present invention, the particulate material is pulverized by a jet stream of heated compressed air. As a result, the temperature in the pulverization chamber rises as compared with the conventional pulverizer, and the pulverized powder particles are contained in the pulverized powder particles. As a solution to this problem, the surface of the plurality of blades constituting the classifying rotor is treated with a release agent, so that the dynamic friction coefficient of about 0.15 to 0.25 is 0.05 to 0. .About.13 is effective for preventing the classified pulverized particles from adhering to the classification rotor and efficiently pulverizing and classifying the powder material.

For the same reason, in the fluidized bed type pulverizing apparatus of the present invention, since the unpulverized and pulverized particulate material is likely to adhere to the side wall of the pulverization chamber, the surface of the side wall of the pulverization chamber is electrically conductive release agent. In addition, it is preferable to perform a surface treatment such as conductive Teflon (registered trademark) or nickel-Teflon (registered trademark) composite plating in consideration of wear resistance.
In the present invention, the particle raw material is pulverized by a jet stream of heated compressed air. As a result, the temperature in the pulverization chamber rises compared to the case of a conventional pulverizer, and the pulverized powder particles It becomes easy to adhere to the side wall of the crushing chamber, and as a solution to this, by treating the surface of the side wall of the crushing chamber with a release agent, the dynamic friction coefficient, which was about 0.15 to 0.25, is 0.05 to 0. .About.13 is effective in preventing the classified pulverized particles from adhering to the side wall and efficiently pulverizing and classifying the powder raw material.

In the method of pulverizing the powder raw material using the fluidized bed pulverizer of the present invention, the desired pulverization efficiency is performed by setting the original pressure of the compressed air supplied to the pulverization nozzle to 0.2 to 1.0 MPa. In the warming pulverization of the present invention, the quality productivity can be further improved according to the production amount and the target particle size, and the powder raw material can be efficiently pulverized and classified over a long period of time.
If the original pressure is less than 0.2 MPa, the pressure of the compressed air is too low and may not be pulverized with the powder raw material. On the other hand, if it exceeds 1.0 MPa, the powder raw material is a desired particle. This is not preferable because it may be in an excessively pulverized state in which the ratio smaller than the diameter increases, or a shock wave may be generated in the flow inside the pulverizing nozzle, resulting in a speed loss.

In the fluidized bed type pulverizing apparatus of the present invention, it is necessary to install a plurality of pulverizing nozzles so that the compressed air injected from each pulverizing nozzle collides with the powder material. The resulting powder raw material is subjected to the first crushing action, and in the heated crushing of the present invention, the quality productivity is further improved according to the production amount and the target particle size, and the powder material is efficiently crushed and classified over a long period of time. can do.
The number of pulverizing nozzles is not limited, but 2 to 8 pulverizing nozzles are preferably used, 2 to 6 pulverizing nozzles are more preferably used, and 3 to 4 pulverizing nozzles are further preferably used. .
Of course, if only one crushing nozzle is provided, the compressed air cannot be primarily collided with the powder raw material. On the other hand, if there are too many crushing nozzles, the production of the apparatus becomes complicated, and the crushing efficiency may be lowered.

Further, in the fluidized bed type pulverizer of the present invention, if one or more classification rotors are provided at the upper part of the pulverization chamber, the pulverized fine powder and coarse powder flow directly into the classification rotor from the pulverization chamber (4). Therefore, centrifugal classification into fine powder and coarse powder can be efficiently performed, which is preferable.
As for the number of classifying rotors, one piece works well when producing a small amount of powder, but for the purpose of producing a large amount of powder, it is necessary to increase the crushing capacity. It is preferable to use 3 or 4 in particular.
In the case of the pulverization method using heated compressed air as in the present invention, a single or a plurality of classification rotors are provided in this way to further improve the quality productivity according to the production amount and the target particle size. The powder raw material can be pulverized and classified efficiently over a long period of time.
If only one classifying rotor is provided, the pulverizing capacity is lowered, which is not desirable. That is, when pulverization / classification is performed under a condition where the supply amount of compressed air is less than 15 m ³ / hr, the pulverization / classification accuracy can be maintained even if a classification rotor having a small diameter is used. If the supply amount exceeds 15 m ³ / hr, it is inevitably necessary to use a classifying rotor with a large diameter, and it becomes difficult to maintain the accuracy of pulverization and classification. It is preferable to provide a plurality of rotors.

In the powder raw material pulverization method using the fluidized bed type pulverization apparatus of the present invention, it is possible to obtain the desired classification efficiency, and to achieve the production amount and the purpose by setting the rotational peripheral speed of the classification rotor to 20 to 70 m / s. It is preferable because quality productivity can be further improved according to the particle size, and the powder raw material can be pulverized and classified efficiently over a long period of time.
If the rotational speed of the classifying rotor is less than 20 m / s, the classifying efficiency may decrease. On the other hand, if the classifying rotor exceeds 70 m / s, the centrifugal force of the classifying rotor becomes too large, and a suction device such as a suction fan. Therefore, the powder raw material to be discharged again returns to the pulverization chamber and is subjected to a pulverization action, so that there is a possibility that the powder raw material is in an over-pulverized state in which the proportion of the powder raw material is smaller than the desired particle size.

FIG. 4 shows the distance L between the crushing nozzles and the height H of the crushing chamber in the schematic sectional view of the fluidized bed type crushing apparatus shown in FIG.
In the fluidized bed type pulverization apparatus of the present invention, the height of the pulverization chamber is set to be able to easily cope with the change in conditions such as the processing amount of the powder raw material and the average particle size and to shorten the switching time. It is effective to define or adjust the regulation according to the target particle size. In particular, the relationship of the height H of the crushing chamber to the distance L between the two crushing nozzles installed opposite to each other is due to the heated crushing. In consideration of cooling of the pulverized raw material, characteristics of the pulverized raw material, and target particle size, it is desirable that 2L ≦ H ≦ 5L.
When the pulverizing chamber height H is less than 2 L, coarse particles in the pulverized powder raw material tend to jump into the classifying rotor, so that the classification accuracy is likely to be lowered, and the pulverized particles are pulverized. The powder material tends to adhere to the surface of the classification rotor, resulting in a decrease in yield and classification accuracy.
In addition, when the grinding chamber height H is larger than 5 L, the distance to the classification rotor is long, and as a result, the powder concentration in the classification rotor tends to increase, resulting in a decrease in classification accuracy. To do.

In the fluidized bed crusher of the present invention, the height H from the crushing nozzle in the crushing chamber to the lower part of the classification rotor as shown in FIG. 4 is the same as the cylindrical wall of the crushing chamber. It is desirable to provide and adjust a spacer (12) formed by connecting the flange pipe.
By this spacer, it becomes possible to cool the powder raw material to be pulverized and arbitrarily adjust the pulverization height according to the characteristics of the powder raw material and the target particle size of the pulverization, and prevent excessive suction of coarse particles by the classification rotor. Therefore, the classification accuracy by the classification rotor can be improved.
The distance L between the nozzles can be adjusted by using a conventional nozzle spacer by a jet mill (circle diamond).

Next, this invention is demonstrated in detail based on a present Example.
The particle size was measured using a multisizer manufactured by Coulter Counter.

Example 1
As the fluidized bed type pulverizer, a counter jet mill 200AFG manufactured by Hosokawa Micron Corporation provided with a compressed air heating device (7) as shown in FIG. 2 was used.
First, a mixture of 75% by weight of a polyester resin, 10% by weight of a styrene acrylic copolymer resin and 15% by weight of carbon black is melt-kneaded by a roll mill, cooled and solidified, and then coarsely pulverized by a hammer mill to prepare an electrophotographic toner. A powder raw material to be used (referred to as toner raw material) was prepared.
Next, after supplying 5 kg of the toner raw material into the pulverization chamber (1) of the fluidized bed pulverizer through the supply pipe (2), the pressure of the compressed air for pulverization is 0.6 Mpa, and the pulverization nozzle (3) is compressed. Grinding and classification were performed under conditions of an air outlet temperature of 40 ° C. and a circumferential speed of the classification rotor (4) of 45 m / s.
Thus, the content of fine powder having a weight average particle size of 6.5 μm and 4 μm or less is 45 POP. %, The coarse powder content of 16 μm or more is 1.0 Vol. % Of toner powder could be obtained at 13 kg / hr.

(Example 2)
As a fluidized bed type pulverizer, a counter jet mill 200AFG manufactured by Hosokawa Micron Co., Ltd., modified as shown in FIG. 3 was used, and 5 kg of the toner raw material described in Example 1 was placed in the pulverization chamber (1). After supplying through the supply pipe (2), the pressure of the compressed air for crushing is 0.6 Mpa, the outlet temperature of the compressed air of the crushing nozzle (3) is 40 ° C., the peripheral speed of the classification rotor (4) is 45 m / s, and The pulverization chamber side wall was adjusted to 20 ° C., and pulverization / classification work was performed.
Thus, the content of fine powder having a weight average particle diameter of 6.5 μm and 4 μm or less is 44 POP. %, A coarse powder content of 16 μm or more is 0.8 Vol. % Toner powder could be obtained at 14 kg / hr.

(Example 3)
As a fluidized bed type pulverizer, a counter jet mill 200AFG manufactured by Hosokawa Micron Co., Ltd., modified as shown in FIG. 3 was used, and 5 kg of the toner raw material described in Example 1 was placed in the pulverization chamber (1). After supplying through the supply pipe (2), the pressure of the compressed air for crushing is 0.6 Mpa, the outlet temperature of the compressed air of the crushing nozzle (3) is 40 ° C., the peripheral speed of the classification rotor (4) is 45 m / s, and The crushing and classification operations were performed by adjusting the side walls of the crushing chamber to 20 ° C. and the bottom of the crushing chamber to 10 ° C., respectively.
Thus, the fine powder content with a weight average particle size of 6.4 μm and 4 μm or less is 42 POP. %, A coarse powder content of 16 μm or more is 0.2 Vol. % Toner powder could be obtained at 14 kg / hr.

(Example 4)
A counter jet mill 200AFG manufactured by Hosokawa Micron Co., Ltd. having a classification rotor (4) provided with a plurality of blades subjected to electroless nickel Teflon (registered trademark) composite plating treatment was modified as shown in FIG. The pulverization and classification work was performed using a fluidized bed pulverizer.
After supplying 5 kg of the toner raw material described in Example 1 into the pulverization chamber (1) through the supply pipe (2), the pressure of the compressed air for pulverization is 0.6 Mpa, and the outlet temperature of the compressed air from the pulverization nozzle (3) is 40. The pulverization / classification operation was performed under the conditions of ℃, the peripheral speed of the classification rotor (4) of 45 m / s, the pulverization chamber side wall adjusted to 20 ° C, and the pulverization chamber bottom to 10 ° C.
Thus, the content of fine powder having a weight average particle diameter of 6.5 μm and 4 μm or less is 44 POP. %, A coarse powder content of 16 μm or more is 0.8 Vol. % Toner powder could be obtained at 14 kg / hr.
Even if the above pulverization / classification operations were carried out continuously for 100 hours, the processing capacity was not changed, and a toner powder having a stable particle diameter could be obtained.
In the electroless nickel Teflon (registered trademark) composite plating treatment, a product having a static friction coefficient of 0.11, a dynamic friction coefficient of 0.09, and a hardness of Hv500 manufactured by Nippon Kanisen Co., Ltd. was used. The same applies to Examples 5 and 6 below.

(Example 5)
Made by Hosokawa Micron Co., Ltd., equipped with a classification rotor (4) provided with a plurality of blades subjected to electroless nickel Teflon (registered trademark) composite plating treatment, and the side walls of the crushing chamber were similarly plated. The counter jet mill 200AFG was pulverized and classified using a fluidized bed pulverizer modified as shown in FIG.
After supplying 5 kg of the toner raw material described in Example 1 into the pulverization chamber (1) through the supply pipe (2), the pressure of compressed air for pulverization is 0.6 Mpa, and the outlet temperature of compressed air of the pulverization nozzle (3) is 40 ° C. The pulverization / classification operation was performed under the condition that the classification rotor (4) had a peripheral speed of 45 m / s, the side wall of the pulverization chamber was adjusted to 20 ° C., and the bottom of the pulverization chamber was adjusted to 10 ° C.
Thus, the fine powder content with a weight average particle size of 6.5 μm and 4 μm or less has a number average of 43 POP. %, The coarse powder content of 16 μm or more is 0.3 Vol. % Toner powder could be obtained at 15 kg / hr.
Even if the above pulverization / classification operations were carried out continuously for 100 hours, the processing capacity was not changed, and a toner powder having a stable particle diameter could be obtained.

(Example 6)
Made by Hosokawa Micron Co., Ltd., which has a classifying rotor (4) provided with a plurality of blades subjected to electroless nickel Teflon (registered trademark) composite plating treatment, and the side walls of the crushing chamber are similarly plated. The counter jet mill 200AFG was further pulverized and classified using a fluidized bed pulverizer modified as shown in FIG.
After supplying 5 kg of the toner raw material described in Example 1 through the supply pipe (2) into the pulverization chamber (1) of the fluidized bed pulverizer, the pressure of the compressed air for pulverization is 0.6 Mpa, and the pulverization nozzle (3) is used. Adjust the outlet temperature of compressed air to 40 ° C, the circumferential speed of the classification rotor (4) to 45 m / s, adjust the side wall of the crushing chamber to 20 ° C and the bottom of the crushing chamber to 10 ° C, and further adjust the crushing height H to The pulverization / classification operation was performed with the distance L between the pulverization nozzles set to 4L.
Thus, the fine powder content with a weight average particle size of 6.5 μm and 4 μm or less has a number average of 43 POP. %, The coarse powder content of 16 μm or more is 0.0 Vol. % Toner powder could be obtained at 15.5 kg / hr.
Even if the above pulverization / classification operations were carried out continuously for 100 hours, the processing capacity was not changed, and a toner powder having a stable particle diameter could be obtained.

(Comparative Example 1)
After supplying 5 kg of the toner raw material described in Example 1 through the supply pipe (2) into the pulverization chamber (1) of a fluidized bed pulverizer (Counter Jet Mill 200AFG) manufactured by Hosokawa Micron Corporation, the compressed compressed air for pulverization is used. The pulverization and classification were performed under the conditions of a pressure of 0.6 Mpa and a peripheral speed of the classification rotor (4) of 45 m / s.
Thus, the weight average particle size is 6.5 μm, 4 μm or less, and the fine powder content is 48 POP. %, 16 μm or less coarse powder content is 1.0 Vol. % Of toner powder was obtained at 13 kg / hr.

It is a conceptual sectional view showing the composition of the conventional fluidized bed type crusher. It is a conceptual sectional view showing an example of a fluidized bed type crusher of the present invention. It is a conceptual sectional view showing other examples of a fluid bed type crusher of the present invention. It is a conceptual sectional view showing still another example of the fluidized bed type pulverizer of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Crushing chamber 2 Supply pipe 3 Crushing nozzle 4 Classification rotor 5 Exhaust pipe 6 Compressed air 7 Compressed air heating device 8 Side wall 9 Crushing chamber bottom 10 Cooling device 11 on the side of the crushing chamber 11 Cooling device 12 on the bottom of the crushing chamber 12 Spacer

Claims (10)

Composed of a substantially cylindrical casing, a pulverization chamber, a plurality of pulverization nozzles for injecting compressed air, a classification rotor provided in the upper portion of the pulverization chamber, a heating means for heating the compressed air before being injected, and At least means for adjusting the temperature of the side wall and bottom of the crushing chamber was provided, and the powder material was pulverized and compressed by compressed air injected from a plurality of crushing nozzles in the crushing chamber supplied with the powder material. Using a fluidized bed type pulverizer for flowing the powder material into the classification rotor rotating from the pulverization chamber and centrifugally classifying the powder material into fine powder and coarse powder, compressed air is supplied in the pulverization chamber supplied with the powder material. A method for producing toner in which a powder material is pulverized by being sprayed from a plurality of pulverizing nozzles, and the pulverized powder material is flown into the classification rotor rotating from the pulverization chamber and centrifugally classified into fine powder and coarse powder The powder material is an electronic copy. A toner raw material obtained by coarsely pulverizing a kneaded material comprising at least a resin and a colorant constituting the toner for heating, heating compressed air having a dew point of −50 ° C. to −10 ° C. to 0 ° C. to 50 ° C., And a temperature of the side wall of the pulverization chamber is adjusted to 0 to 40 ° C. The toner manufacturing method according to claim 1, wherein the temperature of the bottom of the pulverization chamber is −5 to 30 ° C. Method for producing a toner according to claim 1 or 2, characterized in that adjusting the pressure of the compressed air ejected from the grinding nozzles 0.2 to 1.0 MPa. Method for producing a toner according to any one of claims 1 to 3, characterized in that adjusting the circumferential speed of the該分classifying rotor in 20 to 50 m / s. The method for producing toner according to any one of claims 1 to 4, wherein a fluidized bed type pulverizing apparatus provided with a classification rotor having a plurality of blades whose surfaces are treated with a conductive release agent is used . Method for producing a toner according to any one of claims 1 to 5, characterized in that use fluidized-bed pulverizer having a pulverizing chamber inner surface of the side wall is processed with a conductive release agent. Method for producing a toner according to any one of claims 1 to 6, characterized by using fluidized-bed pulverizer having 2-8 grinding nozzles. Method for producing a toner according to any one of claims 1 to 7, characterized by using a fluidized-bed pulverizer having 1-5 classification rotor. The fluidized bed type pulverizing apparatus is used so that the distance L between two pulverizing nozzles installed correspondingly and the height H of the pulverizing chamber satisfy a relationship of 2L ≦ H ≦ 5L. The method for producing a toner according to any one of 1 to 8 . The method for producing toner according to claim 9 , wherein a fluidized bed type pulverizing apparatus provided with a spacer for adjusting the height H of the pulverizing chamber is used .

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