JP4836634B2 - Fluidized tank type pulverizing and classifying machine for producing electrophotographic toner and toner production method using the same - Google Patents

Description

  In the present invention, a toner raw material obtained by melt-kneading a composition comprising at least a binder resin and a colorant constituting an electrophotographic toner and cooling and solidifying and then coarsely pulverizing is further pulverized by a fluidized tank pulverizer. The present invention relates to an improved fluidized tank type pulverizing classifier used for classifying and producing a small particle size toner, and a toner production method using the same.

First, an outline of a fluidized tank type pulverizing classifier which is a kind of conventional pulverizing apparatus will be described with reference to FIG.
The fluidized tank type pulverizing / classifying machine is usually cylindrical and has a fluidized tank part, and a plurality of air nozzles as pulverizing means are provided toward the center in the lower part of the outer peripheral wall. The air nozzle pulverizes the toner material to be pulverized by causing the suspended high-pressure jet to collide with each other in the fluidized tank. In order to maintain the pulverization efficiency and avoid excessive pulverization, it is quickly sent to the classifying means, and those having a desired particle size are selected by the classifying means.

The example of FIG. 1 is a combination of pulverizing means and classification means.
The raw material particles (2) supplied from the raw material supply unit (7) into the fluid tank (1) are accelerated by the high-pressure jet stream ejected from the plurality of pulverization air nozzles (3), and the particles are at the intersection of the opposing jet streams. Meet at, and crushed by mutual collision of particles. After the raw material particles swirl and stay in the fluidized tank for a certain time and are repeatedly pulverized, they are conveyed to the classifying rotor (4) provided at the upper part of the fluidized tank by the updraft to obtain desired particle size powder and coarse powder. The particles having a desired particle size are classified as final product toner, while the coarse powder is recirculated in a fluidized tank and subjected to a pulverization step until a predetermined particle size is collected as final product toner.
Various improved techniques have been proposed for the fluidized tank pulverization method.
For example, Patent Document 1 (Japanese Patent Laid-Open No. 5-146704) discloses a method for controlling the supply amount of toner raw material particles in order to eliminate variation in classification accuracy. Is a device that measures the solid gas concentration in the pulverizer so that the pulverizer can be operated easily. Patent Document 3 (Japanese Patent Application Laid-Open No. 11-070340) discloses an air flow, pulverized raw material and Techniques have been proposed for minimizing turbulent loss caused by the speed difference.

  Patent Document 4 (Japanese Patent Laid-Open No. 2-294660), Patent Document 5 (Japanese Patent Laid-Open No. 2-294661), Patent Document 6 (Japanese Patent Laid-Open No. 2-294661) and Patent Document 7 (Japanese Patent Laid-Open No. 2-294663). No. 1) discloses a method for producing toner having a normal particle diameter by a pulverization / classification method. The first classification means and the second classification means are used as the classification means, and the toner is used as the operation time of the classification means becomes longer. As a countermeasure, the soft resin constituting the toner adheres to the powder discharge tube constituting the second classifying means, which causes coarse powder generation and becomes a problem in the final product toner. At least a part of the body discharge pipe or the like is made of a fluororesin so as to prevent adhesion of a soft resin.

In recent years, as image quality formed by an electrophotographic method, high definition is strongly desired, and accordingly, there is an increasing demand for toner having a smaller particle size. The small particle size toner has a weight average particle size of about 4.5 to 8.0 μm.
When the toner has a small particle size, the state of the particles in the pulverizer is naturally different from that of the conventional toner, and accordingly, it is necessary to change the production setting conditions in the pulverizer employed.
Regarding the state of the particles in the pulverizer, for example, when the diameter of particles having a true specific gravity of 1.2 is reduced from 9.0 μm to 7.5 μm and further to 6.0 μm, the number of particles per unit weight (pieces / gram) starts from 2.7 billion. When the powder concentration is 0.05%, the center-to-center distance is changed from 90 μm to 75 μm and further 60 μm, and the Brownian motion is increased from 2 μm / sec to 2.52 μm / sec and further 3 μm / sec. Each changes greatly.

However, when a toner powder having a small particle diameter is produced by the fluidized tank type pulverization classification method, there are undesirable problems such as 1) a decrease in the pulverizing ability, 2) mixing of coarse particles and 3) an increase in the content of ultrafine particles. It is a result that occurs.
The ultrafine powder has a particle size of about 4 μm or less, and the coarse powder has a particle size of about 16 μm or more. However, the contents of the ultrafine powder and coarse powder obtained by the conventional fluidized tank pulverization classification method are as follows: Is quite expensive.

If the proportion of ultrafine particles in the pulverized product increases and aggregates thereof are generated, even if the ultrafine particles are removed in the next classification step to obtain a powder having a desired particle size, The rate drops significantly. In addition, a developer having a large ratio of ultrafine particles and coarse particles does not have a stable charge amount, so that the density of an obtained image is low.
That is, if the ratio of ultrafine particles and coarse particles is large, the charge amount of the toner is affected, and the over-pulverized toner causes a scumming phenomenon, and the insufficiently pulverized toner deteriorates the image quality due to poor transfer. . Further, in production, since an excessive load is applied to the classifier, there is a problem that classification efficiency is low and energy efficiency of pulverization is low.
These problems faced in the manufacture of small particle size toners and their production are new ones that have not been recognized in the past, and of course no solutions have been proposed.

Japanese Patent Laid-Open No. 5-146704 JP-A-6-285386 Japanese Patent Laid-Open No. 11-070340 JP-A-2-294660 JP-A-2-294661 Japanese Patent Laid-Open No. 2-294661 JP-A-2-294663

  An object of the present invention is to produce a toner for forming an electrophotographic image with a small particle diameter, which has a small content of ultrafine particles and coarse particles, and as a result, a stable charge amount and a high-definition image can be obtained. An object of the present invention is to provide a fluidized tank pulverizer and a toner manufacturing method using the same, which are economically advantageous in terms of production efficiency.

The above problems are solved by the present invention described below.
(1) “A fluidized tank type pulverizing and classifying machine for producing an electrophotographic toner having a cylindrical fluidized tank and having at least a pulverizing means and a classifying means, wherein at least an inner wall surface of the fluidized tank is subjected to blasting treatment. The inner wall surface subjected to the blast treatment has an arithmetic average surface roughness (Ra) of 0.05 to 1.0 μm, a maximum height (Ry) of 1.0 to 5.0 μm, and ten points. An electrophotographic toner manufacturing fluid tank having an average roughness (Rz) of 1.0 to 5.0 μm and a root mean square roughness (Rq Ra) of 0.5 to 1.0 μm Type grinding classifier.
"
(2) “The fluid tank has an annular protrusion structure in which a part of the inner wall projects in the center direction of the tank, and the annular protrusion structure has a vertical cross section in the cylindrical axis direction of the fluidized bed that is bi-directional. Gradually projecting in the center direction in the tank, and has a ring-like shape with a convex top at an intermediate height position between the upper and lower bidirectional directions, and the convex top is in the horizontal direction of the cylindrical flow tank. The fluidized tank type pulverizing and classifying machine for producing electrophotographic toner according to item (1), wherein the area is minimized .
(3) “The annular projection structure projecting in the center direction in the tank is relative to the cross-sectional area (a) in the direction perpendicular to the cylindrical axis (A-A ₁ ) of the portion of the fluid tank that is not reduced in diameter by the annular projection structure. The cross-sectional area (b) formed in the direction perpendicular to the cylindrical axis (P-P ₁ ) of the convex top (P) portion of the protrusion structure to reduce the diameter satisfies the following relationship (2): ) Fluidized tank type pulverization classifier;

」、
（４）「前記槽内中心方向に張り出した環状突起構造の円筒軸方向に平行な底辺（ＱＲ）が、流動槽の鉛直方向高さ（Ｈ）に対し下記の関係を満たすことを特徴とする前記第（３）項に記載の流動槽式粉砕分級機；

"
(4) “The base (QR) parallel to the cylindrical axis direction of the annular projection structure projecting in the center direction in the tank satisfies the following relationship with respect to the vertical height (H) of the fluid tank. Fluidized tank type pulverizing and classifying machine according to item (3);

」、
（５）「槽内中心方向に張り出した環状突起構造の円筒状流動槽の水平方向内部面積を最小にする凸状頂部（Ｐ）の装着高さが、流動槽の鉛直方向高さ（Ｈ）に対し下記の関係を満たすことを特徴とする前記第（３）項又は第（４）項に記載の流動槽式粉砕分級機；

"
(5) “Mounting height of the convex top (P) that minimizes the horizontal internal area of the cylindrical flow tank having an annular protrusion structure projecting in the center direction in the tank is the vertical height (H) of the flow tank. The fluidized tank type pulverization classifier according to item (3) or (4), wherein the following relationship is satisfied:

」、
（６）「前記環状突起構造が、導電性離型剤処理が施されたものであることを特徴とする前記第（２）項乃至第（５）項のいずれかに記載の流動槽式粉砕分級機」、
（７）「流動槽式粉砕分級機であって、内蔵される分級ローターの羽根及び駆動部固定部分に導電性離型剤処理を施し、ローター内部を通過する粉体の付着・凝集・融着・固着を抑制することを特徴とする前記第（１）項乃至第（６）項のいずれかに記載の流動槽式粉砕分級機」、
（８）「粉砕圧縮エアーの露点温度が−１０℃〜−４０℃で供給され、粉砕によって発生する装置内の付着・凝集・融着・固着を抑制することを特徴とする前記第（１）項乃至第（７）項のいずれかに記載の流動槽式粉砕分級機」、
（９）「前記第（１）項乃至第（８）項のいずれかに記載の流動槽式粉砕分級機を用いて、粉砕分級することを特徴とするトナー製造方法」

"
(6) The fluidized tank type pulverization according to any one of (2) to (5), wherein the annular protrusion structure is subjected to a conductive release agent treatment. Classifier ",
(7) “A fluidized tank type pulverizing and classifying machine, in which the blades of the built-in classifying rotor and the fixed part of the driving unit are treated with a conductive release agent to adhere, agglomerate and fuse the powder passing through the rotor. -The fluidized tank type pulverizing and classifying device according to any one of (1) to (6) above, wherein sticking is suppressed.
(8) The above-mentioned (1), wherein the dew point temperature of the pulverized compressed air is supplied at -10 ° C to -40 ° C to suppress adhesion / aggregation / fusion / adhesion in the apparatus caused by pulverization. The fluidized tank type pulverizing / classifying machine according to any one of Items to (7),
(9) “Toner production method characterized by pulverizing and classifying using the fluidized tank pulverizing and classifying machine according to any one of (1) to (8) ”

  According to the pulverization / classification apparatus according to the first aspect of the present invention, a stable pulverized product can be obtained in which the amount of powder adhering in the fluidized tank is small and there is no aggregation compared to the conventional pulverization method. Further, according to the pulverizing / classifying apparatus according to claims 2 to 6, a stable pulverized product with less powder adhesion and no aggregation can be obtained by increasing the convection speed in the fluidized tank as compared with the conventional pulverizing method. Further, according to the pulverizing / classifying apparatus according to claim 7, compared with the conventional pulverizing method, there is less adhesion of the powder contacting the inside and outside of the classifier and there is no agglomeration. can get. Further, according to the pulverizing / classifying apparatus according to claim 8, since the liquid cross-linking force of the powder can be reduced as compared with the conventional pulverizing method, the adhesion of the powder is less, and the classification state is always constant and stable because there is no aggregation. A crushed product is obtained. The pulverizing / classifying apparatus according to claim 9 is more stable than the conventional pulverizing method, so that it is energy efficient when used for toner production, which is advantageous in terms of production efficiency and economically. . In addition, if the toner obtained by pulverization is used for image formation, the toner charge amount is stabilized from the stability of the particle size, and good and stable image quality can be obtained with respect to the background contamination and the transfer failure problem. Further, according to the pulverization / classification apparatus according to claims 10 to 13, for example, a pulverized toner having a predetermined particle diameter in an average particle diameter range of 4 to 12 μm can be obtained more efficiently, and there is no aggregation. Is always constant and a stable pulverized product is obtained, which is more stable than conventional pulverization methods, so that it is highly energy efficient when used in toner production, and is more advantageous in terms of production efficiency and economy. Has an effect.

The inventors of the present invention have observed in detail the cause of problems that occur as the toner particle size is reduced from the viewpoint of the mechanism.
In the fluidized tank type pulverizer method, as described above, the raw material particles pulverized in the fluidized tank are classified by the classification rotor, and the classified coarse powder is recirculated in the fluidized tank until a predetermined particle size is obtained. Although it is subjected to a pulverization step, recirculation is performed many times in order to reduce the particle size, and as a result, it was confirmed that ultrafine particles increased due to excessive pulverization.
Furthermore, in the process of pulverizing the powder particles by repeating recirculation, the powder particles frequently adhere, accumulate, adhere to the inner wall of the pulverizer, and the deposit grows and collapses. I understood.
There is a patent (Japanese Patent Laid-Open No. 2003-280263) in which a release agent is applied in the device as a means for preventing this adhesion and accumulation. However, since the mainstream of the release agent is a Teflon (registered trademark) material, the volume resistance value is Although it is high and the contact area with the device matrix is reduced, the amount of charge is increased and the adhesion has not been completely removed.

If collapse occurs repeatedly, the dust concentration or solid gas concentration in the pulverizer / classifier becomes unstable, affecting not only the operating conditions but also preventing stable pulverization. Over time, not only the coarse powder but also the ultrafine powder that has become an aggregate remains unclassified and is considered to be mixed with the toner product.
In general, the smaller the particle size, the higher the cohesiveness and the lower the fluidity of the powder. As a result, powder particles adhere to the inner wall of the pulverizer, deposit, adherence, etc. It is thought to do.
It is generally known that when the particle size of the particles becomes small and the distance between the particles approaches and the concentration becomes high, the rate of aggregation and aggregation between the particles increases extremely.
According to the verification results described above, in the pulverization classification process (fine pulverization + coarse powder classification) in the production of the toner having a small particle diameter, if adhesion, aggregation, fusion, and fixation of particles on the inner wall of the apparatus can be suppressed, Since it is assumed that the above problems can be solved, the present inventors have repeatedly studied from both aspects of the material and structure of the pulverizer itself, and as a result, found that the above problems can be solved by two technical means, The present invention has been reached.

That is, the present invention created by studying from the viewpoint of material is a fluidized tank type pulverizing and classifying machine for producing an electrophotographic toner having a cylindrical flow tank and having at least a pulverizing means and a classifying means. A layer made of a release agent is provided on at least the inner wall surface.
By providing such a layer, it is possible to suppress at least one of adhesion, aggregation, fusion, and fixation of ultrafine particles on the inner wall of the apparatus.

FIG. 2 is a conceptual diagram showing an example of a fluidized tank type pulverizing and classifying machine of the present invention in which fine irregularities are provided on the inner surface of a fluidized tank made of a blast material.
In FIG. 2, the layer (5) having fine irregularities is provided on the entire inner wall of the fluid tank (1). However, it is not essential to provide the layer on the entire inner wall, and it is effective to provide a part of the layer. .
The blast used in the present invention is, as long as it is provided with a layer on at least the inner wall surface of the fluidized tank and has irregularities that prevent toner particles, particularly ultrafine particles from adhering as much as possible. It is not limited.
An object of the present invention is to provide a blasting process capable of reducing the contact area with the powder and largely removing the adhesion while maintaining the material characteristics of the pulverizer itself without increasing the volume resistance value of the machine base.

<Material and structure of pulverizer itself>
As a specific example of the blast treatment, the pressure of resin powder having an average particle diameter of 20 to 150 μm is adjusted in the range of 0.1 to 0.6 Mpa, and the spraying mother body is washed and degreased, and then the average particle diameter is 1 to 50 μm. After adjusting the pressure in the range of 0.05 to 0.3 Mpa using a ceramic powder and applying fine irregularities to the spray base, the average particle size is 0.05 to 0.3 Mpa using a glass powder of 1 to 30 μm. The surface of the blasted surface is polished by spraying with pressure adjustment in the range of 0.05 to 1.0 μm, Ry is 1.0 to 5.0 μm, and Rz is 1.0 to 5.0 μm. , Rq Ra is 0.5 to 1.0 μm. For the blasting process, for example, a direct pressure blasting machine (MicroFinish 15-3) can be used.

Each of the following arithmetic average values, which is a parameter representing the surface roughness, at each portion randomly extracted from the surface of the object (hereinafter referred to as a symmetry plane).
Arithmetic mean roughness (Ra)
Maximum height (Ry)
Ten-point average roughness (Rz)
Root mean square roughness (Rq)
Average spacing of irregularities (Sm)
Average distance between local peaks (S)
Load length ratio (tp)
In the case of the present applicant, the symmetry plane is often a curved surface. Therefore, the ten-point average roughness (Rz) is adopted for the purpose of suppressing the influence of the surface waviness. Only in special cases, both Rz and Ra are displayed (cut-off value).

<10-point average roughness (Rz)>
The average of the elevation values (Yp) of the highest valley bottom from the highest peak to the fifth measured from the roughness line by the reference length in the direction of the average line and measured in the direction of the vertical magnification from the average line of the extracted part. The sum of the value and the average value of the absolute values of the altitudes (Yv) of the bottom valley from the lowest valley bottom (Yv) is obtained (the following formula), and this value is expressed in micrometers (μm) (FIG. 5). reference).

<Arithmetic mean roughness (Ra)>
A reference length was extracted from the roughness curve in the direction of the average line, the X-axis was taken in the direction of the sampling average line, the Y-axis was taken in the direction of the vertical magnification, and the roughness curve was expressed by y = f (x). Sometimes the value obtained by the following equation is expressed in micrometers (μm) (see FIG. 6).

（Ｌ：基準長さ）
なお、粉砕機を構成する流動槽の材質としては、ＳＵＳ材（ステンレス鋼）、ＳＳ材（一般構造用鋼板）等が一般的に用いられている。

(L: Reference length)
In addition, as a material of the fluid tank which comprises a grinder, SUS material (stainless steel), SS material (general structural steel plate), etc. are generally used.

  The classifying rotor built in the classifying means constituting the pulverizing classifier of the present invention is provided with a blade part and a driving part, but when the fixed part is subjected to blasting in the same manner as the classifying machine, the inside of the rotor It is effective to suppress at least one of adhesion, aggregation, fusion, and adhesion of the powder passing through the glass.

On the other hand, a fluidized tank type pulverizing and classifying machine for producing an electrophotographic toner having a cylindrical flow tank of the present invention, which has been studied and created from the structural aspect, and having at least a pulverizing means and a classifying means, is provided on the inner wall of the fluid tank. The portion has an annular protrusion structure projecting toward the center in the tank.
This "annular protrusion structure with a part of the inner wall of the fluid tank projecting toward the center of the tank" means that the inner wall of the cylindrical fluid tank is gradually reduced in diameter from both sides of the fluid tank. This is a convex structure, in which inner walls located in all directions in a substantially vertical direction with respect to the same point of the cylindrical body axis are continuously formed in an annular shape.
When the inner wall of the fluidized tank cylindrical part is structured in this way, the behavior of the airflow in the fluidized tank changes, such as the passage convection speed increases at the protruding structure part, and the self-cleaning ability inside the fluidized tank generated during pulverization classification This increases, making it difficult for the ultrafine particles to adhere to and aggregate on the inner wall, thereby solving the problem of the present invention.

An example of the pulverization classifier of the present invention having a protruding structure will be described with reference to FIG.
In FIG. 3, PQR and P ₁ Q ₁ R ₁ represent the cross section of the protrusion structure formed on the inner wall of the cylindrical body (enlarged view is shown in a circle) with a triangle. The two triangles are substantially the same shape, and the vertices (P) and (P ₁ ) are in corresponding positions in the direction substantially perpendicular to the cylinder axis, and (Q) and (Q ₁ ) and (R) and (R The positional relationship of ₁ ) is the same. This triangle continuously forms around the inner wall to form a protruding structure in a ring shape.
Since (PQR) and (P ₁ Q ₁ R ₁ ) in this cross-sectional view are triangular, it means that the tip of the protruding structure is an acute angle, which is a preferable requirement, but is not essential.

  If this projecting structure satisfies the following conditions, it is particularly effective to make it difficult to attach and agglomerate the ultrafine powder on the inner wall of the fluidized tank during the operation of the pulverized powder class. Yes, it is preferable. In addition, each code | symbol is represented by FIG.

Condition 1.
The cross-sectional area (b) formed at the apex (P-P ₁ ) of the protrusion structure (PQR) with respect to the cross-sectional area (a) in the direction perpendicular to the cylindrical axis of the fluid tank (A-A ₁ ) Satisfy 1);
a / 2 ≦ b ≦ 9a / 10... Formula (1)

Condition 2.
In addition to condition 1, (QR) corresponding to the bottom of the slope (PR) up to the apex (P) of the protrusion structure (PQR) is a relational expression for the vertical height (H) of the fluid tank ( Satisfy 2);
H / 10 ≦ QR ≦ 5H / 10... Formula (2)

Condition 3.
In addition to conditions 1 and 2, the mounting height of the apex (P) of the protrusion structure (PQR) satisfies the relational expression (3) with respect to the vertical height (H) of the fluid tank;
H / 10 ≦ P ≦ 8H / 10... Formula (3)
In particular, according to the pulverizing and classifying machine having the protruding structure satisfying the condition 3, fine pulverized / coarse powder classified ascending is collected and sucked into the cyclone, and not only fluidization at the time of pulverization but also the speed of convection reaching the upper partial rotor It is effective to control simultaneously.

  The electrostatic image developing toner obtained by pulverizing and classifying the toner raw material using the fluidized tank type pulverizing / classifying apparatus of the present invention described above has very small contents of ultrafine powder and coarse powder, respectively. Therefore, when such a toner is used, since the charge amount is stable, a high-definition image can be obtained by electrophotography.

  Further, when the pulverized compressed air is supplied at a dew point temperature of −10 ° C. to −40 ° C. when the toner raw material is pulverized and classified using the fluidized tank type pulverizing / classifying device of the present invention, Since the humidity of the liquid becomes completely dry and the liquid cross-linking force between the pulverized particles is lost, it is effective to suppress adhesion, aggregation, fusion, and fixation in the apparatus.

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples.
<Example 1>
After washing and degreasing the blasting resin powder with an average particle size of 80 μm and 0.3 Mpa spraying mother body, using a ceramic powder with an average particle size of 40 μm, the spraying mother body was finely dented with 0.2 Mpa. After the application, the pressure of the average particle size is 20 μm using glass powder, the pressure is adjusted at 0.2 Mpa, the surface is polished by spraying, Ra of the blasted surface is 0.07 μm, Ry is 3.0 μm, and Rz is A blast treatment of 2.5 μm and Rq Ra of 0.7 μm was applied to the inner wall of the fluidized tank.
The effect of the present invention by this pulverization classifier was confirmed as follows.
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 was melt-kneaded by a roll mill, cooled and solidified, and then roughly pulverized by a hammer mill to prepare a toner raw material.
After supplying 500 kg of the toner raw material to the pulverizing and classifying machine, pulverizing and classifying was performed. As a result, the content of ultrafine powder having a weight average particle diameter of 6.4 μm and a particle diameter of 4 μm or less was 47 pop. %, The coarse powder content of 16 μm or more is 0.02 Vol. % Of toner could be obtained.
The crushing capacity at that time was 55 g / m ³ with respect to the crushing supply air flow rate (m ³ / min). After the pulverization treatment, the inner wall of the fluid tank was confirmed. As a result, the powder adhered to the inner wall of the tank at 1.0 mm and there was no aggregation. A multisizer manufactured by Coulter Counter was used for the particle size measurement.

<Comparative Example 1>
300 kg of the same toner raw material as in Example 1 was pulverized and classified without blasting using the apparatus shown in FIG. 1 (the material of the fluid tank of the pulverizer is SUS303). After 300 kg pulverization, the processing capacity decreased to 40 g / m ³ with respect to the pulverized supply air flow rate (m ³ / min), and when the inner wall of the fluidized tank was confirmed, adhesion in the tank was confirmed to be 30 mm and adhesion aggregation was confirmed.

<Example 2>
In fluidized bed pulverizer shown in FIG. 3, b in the proper range a / 2 ≦ b ≦ 9a / 10 of the cross-sectional area b of relative cross sectional area a of the fluidization vessel is formed at the apex P-P ₁ of the projection PQR When the inner wall was subjected to the same blasting treatment as in Example 1 and pulverized 500 kg of toner, the content of fine powder having a weight average particle size of 6.3 μm and 4 μm or less was 48 pop. %, And a coarse powder content of 16 μm or less was able to obtain a toner particle diameter of 0.03 Vol% on a weight average. The crushing ability at that time was 60 g / m ³ with respect to the crushing supply air flow rate (m ³ / min), and after confirming the inner wall of the fluidized tank, the adhesion inside the tank was 1.0 mm and there was no aggregation.

<Example 3>
In the fluidized tank pulverizer shown in FIG. 3, RQ corresponding to the bottom constituting the inclination to the apex P (P ₁ ) of the projection PQR is H / 10 ≦ PQ ≧ 5H with respect to the vertical height H of the fluidized tank. / 10 is a fluidized tank type pulverizing and classifying machine characterized in that the convection speed inside the fluidized tank is changed, and RQ = 4H / 10 is used to perform the same blast treatment as in Example 1 to pulverize 500 kg of toner. As a result, the fine powder content of 4 μm or less with a weight average particle size of 6.25 μm was 47 pop. %, The coarse powder content of 16 μm or less is 0.02 Vol. % Toner particle size could be obtained. The crushing capacity at that time was 55 g / m ³ with respect to the crushing supply air flow rate (m ³ / min), and after confirming the inner wall of the fluidized tank, adhesion in the tank was 0.5 mm and there was no aggregation.

<Example 4>
In the fluidized tank pulverizer shown in FIG. 3, the same blasting treatment as in Example 1 was performed using protrusions of P = 4H / 10, and 500 kg of toner was pulverized, and the weight average particle size was 6.2 μm and 4 μm or less. Has a fine powder content of 48 pop. %, A toner particle diameter of 16 vol. The pulverization capacity at that time was 65 g / m ^{3 with} respect to the pulverization supply air flow rate (m ³ / min). After confirming the inner wall of the fluidized tank, the adhesion inside the tank was 0.5 mm and there was no aggregation.

< Comparative Example 3 >
In the fluidized tank pulverizer shown in FIG. 3, the blasted surface with a Ra of 0.03 μm, Ry of 0.5 μm, Rz of 0.7 μm, and Rq Ra of 0.3 μm is applied to the inner wall of the fluidized tank. gave. A mixture of 75% by weight of the same polyester resin as in Example 1, 10% by weight of styrene acrylic copolymer resin and 15% by weight of carbon black was melt-kneaded in a roll mill, cooled and solidified, and then roughly pulverized in a hammer mill to obtain a toner raw material. Got ready. After supplying 500 kg of the toner raw material to the pulverizing and classifying machine, pulverizing and classifying was performed. As a result, the content of ultrafine powder having a weight average particle diameter of 6.6 μm and a particle diameter of 4 μm or less was 47 pop. %, The coarse powder content of 16 μm or more is 0.06 Vol. % Of toner could be obtained. The crushing capacity at that time was 40 g / m ³ with respect to the crushing supply air flow rate (m ³ / min). After the pulverization treatment, the inner wall of the fluidized tank was confirmed. As a result, the adhesion of the powder on the inner wall of the tank was 29 mm and the blast surface in the fluidized bed was too smooth.

It is a figure which shows the conventional fluidized tank type crushing apparatus. It is a figure which shows the fluid tank type | formula grinder of this invention. It is another figure which shows the fluid tank type | formula grinder of this invention. It is another figure which shows the fluid tank type crusher cross section of this invention. It is a figure explaining how to obtain the ten-point average roughness (Rz). It is a figure explaining how to obtain | require arithmetic average roughness (Ra).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fluid tank 2 Raw material particle 3 Grinding air nozzle 4 Classification rotor 5 Blasting surface 6 Grinding compressed air 7 Raw material supply part H Height of fluid tank vertical direction P Projection Q Projection R Projection P ₁ Projection Q ₁ Projection R ₁ Protrusion

Claims (9)

A fluidized tank type pulverizing and classifying machine for producing an electrophotographic toner having at least a pulverizing means and a classifying means provided with a cylindrical fluidized tank, wherein at least an inner wall surface of the fluidized tank is subjected to blasting, and the blasting The inner wall surface subjected to is an arithmetic average surface roughness (Ra) of 0.05 to 1.0 μm, a maximum height (Ry) of 1.0 to 5.0 μm, and a ten-point average roughness ( Rz) is 1.0 to 5.0 μm, and root mean square roughness (Rq Ra) is 0.5 to 1.0 μm. . The fluidized tank has an annular protrusion structure in which a part of an inner wall projects in the center direction of the tank, and the annular protrusion structure has a longitudinal section in a cylindrical axis direction of the fluidized bed gradually from the upper and lower bidirectional directions. Projecting in the center direction in the tank, it has a ring shape with a convex top at an intermediate height position between the upper and lower bidirectional directions, and the convex top minimizes the horizontal inner area of the cylindrical flow tank. The fluidized tank type pulverizing and classifying machine for producing an electrophotographic toner according to claim 1, wherein The annular projection structure projecting in the center direction in the tank is reduced in diameter with respect to the cross-sectional area (a) in the direction perpendicular to the cylindrical axis (A-A ₁ ) of the portion of the fluid tank that is not reduced in diameter by the annular projection structure. convex top of the projection structure (P) of the cross-sectional area formed by the cylinder axis perpendicular _{(P-P 1) (b} ) are flow cell as claimed in claim 2, characterized in that satisfies the following Type grinding classifier.

The base (QR) parallel to the cylindrical axial direction of the annular projection structure projecting in the center direction of the tank satisfies the following relationship with respect to the vertical height (H) of the fluid tank. The fluidized tank type pulverizing and classifying machine described.

The mounting height of the convex top portion (P) that minimizes the horizontal inner area of the cylindrical flow tank with an annular protrusion structure projecting toward the center of the tank is as follows with respect to the vertical height (H) of the flow tank: The fluidized tank type pulverization classifier according to claim 3 or 4, wherein the relationship is satisfied.

6. The fluid tank type pulverizing / classifying machine according to claim 2, wherein the annular protrusion structure is subjected to a conductive release agent treatment. It is a fluidized tank type pulverizing and classifying machine, and the conductive rotor release agent treatment is applied to the blades of the built-in classification rotor and the fixed part of the drive unit to suppress the adhesion, aggregation, fusion and adhesion of powder passing through the rotor. The fluidized tank type pulverizing and classifying machine according to any one of claims 1 to 6. The dew point temperature of the pulverized compressed air is supplied at -10 ° C to -40 ° C to suppress adhesion / aggregation / fusion / adhesion in the apparatus caused by pulverization. The fluidized tank type pulverizing and classifying machine described. A method for producing a toner, comprising performing pulverization and classification using the fluidized tank pulverizing and classifying machine according to claim 1.

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