JP3352313B2 - Manufacturing method of 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 method for efficiently pulverizing and classifying small-sized solid particles having a binder resin to efficiently obtain a toner for developing electrostatic images having a sharp particle size distribution. And a method for producing a toner.

[0002]

2. Description of the Related Art In image forming methods such as electrophotography, electrostatography and electrostatic printing, a toner for developing an electrostatic image is used. In recent years, with high image quality and high definition of copiers and printers, the performance required for toner as a developer has become more severe, the particle size of the toner has become smaller, and the particle size distribution of the toner has There has been a growing demand for sharp particles that do not contain particles and that contain few ultrafine powders.

[0003] As a general method for producing a toner for developing an electrostatic image, there are a binder resin for fixing to a material to be transferred, various colorants for giving a color as a toner, and a method for giving a charge to particles. Using a charge control agent as a raw material, or
In a so-called one-component developing method as disclosed in JP-A-42141 and JP-A-55-18656, in addition to these, various magnetic materials for imparting transportability or the like to the toner itself are used. Accordingly, for example, other additives such as a release agent and a fluidity-imparting agent are added and dry-mixed, and thereafter, the mixture is melt-kneaded by a general-purpose kneading device such as a roll mill or an extruder, cooled and solidified, and then kneaded. Particles are refined by various types of pulverizers, such as jet stream type pulverizers and mechanical collision type pulverizers, and the obtained coarsely pulverized products are introduced into various air classifiers and classified to obtain the particle size required for toner. A sorted classified product is obtained, and if necessary, a fluidizing agent, a lubricant and the like are externally added and dry-mixed to obtain a toner to be used for image formation. In the case of a toner used in a two-component developing method, various magnetic carriers are mixed with the above-mentioned toner, and then used for image formation.

Conventionally, a method shown in a flowchart of FIG. 11 has been generally adopted in order to obtain toner particles composed of fine particles having a required particle size. That is, as shown in FIG. 11, a powder raw material composed of a coarsely pulverized toner is first continuously or sequentially supplied to a first classification means in a first classification step, and classified into coarse powder and fine powder. Is done.
Among the classified ones, coarse powder mainly composed of a coarse particle group having a specified particle size or more is sent to a crushing means and finely crushed.
It is again introduced into the first classifying means, where the classification is performed and circulated. Then, the fine powder mainly composed of particles containing particles within the specified particle size range and particles smaller than the specified particle size is sent to the second classifying means, and the medium powder mainly composed of particles having the specified particle size is used. And a fine powder (hereinafter, referred to as an ultrafine powder) mainly composed of a group of particles having a specified particle size or less. The obtained intermediate powder is used as a classified product for producing a toner.

Various pulverizers are used as a pulverizing means used in the above-mentioned conventional classification / pulverization process. For pulverizing a toner coarse powder mainly composed of a binder resin, a jet air flow as shown in FIG. 9 is used. A jet-type pulverizer using the above method, particularly a collision-type pulverizer is used. In such an impingement type air flow pulverizer using a high-pressure gas such as a jet air flow, a powder raw material, which is an object to be ground, is transported by a jet air flow, injected from an outlet of an acceleration tube, and the powder raw material is discharged from an outlet of the acceleration tube. Colliding with the collision surface of the collision member provided opposite the opening surface of
The powder raw material is pulverized by the impact force. For example, in the collision-type air-flow pulverizer shown in FIG.
A collision member 164 is provided so as to face the outlet 163 of the acceleration tube 162 to which the tube 61 is connected. The high-pressure gas supplied to the acceleration tube 162 allows the powder material supply port 165 to communicate with the acceleration tube 162 in the middle. The powder raw material is sucked into the accelerating tube 162, and the powder raw material is ejected together with the high-pressure gas to collide with the collision surface 166 of the collision member 164. 167.

However, in the collision type air-flow crusher shown in FIG. 9, since the supply port 165 for the crushed object is provided in the middle of the acceleration tube 162, the powder to be crushed introduced into the acceleration tube 162 is sucked. Immediately after passing through the pulverized material supply port 165, the raw material is dispersed in the high-pressure airflow while changing the flow path toward the acceleration pipe outlet 163 by the high-pressure airflow ejected from the high-pressure gas supply nozzle 161, and is rapidly accelerated. . In this state, relatively coarse particles of the material to be pulverized flow in the lower part of the accelerating tube due to the effect of inertia force, while relatively fine particles flow in the higher part of the accelerating tube. The raw material particles are not sufficiently uniformly dispersed, and partially concentrate and collide with the collision member 164 in the pulverization chamber 168 while being separated into a flow having a high concentration of the material to be pulverized and a flow having a low concentration. For this reason, there has been a problem that the pulverization efficiency is apt to decrease, and the treatment capacity is likely to decrease.

Further, the collision surface 166 has
Since a portion having a high dust concentration composed of the crushed material before the collision and the crushed material after the collision easily occurs locally on the collision surface 166, if the crushed material contains a low-melting substance such as a resin, the crushed material is used. Fusion, coarse-graining, aggregation or the like is likely to occur. Further, when the object to be ground has abrasion properties, local powder wear is likely to occur on the collision surface 166 of the collision member 164 and the accelerating tube 162, and the frequency of replacement of the collision member 164 and the like increases. There is a point to be improved from the viewpoint of stable production of toner.

[0008] Conventionally, various classifiers have been used as airflow classifiers which are connected to the above-mentioned impingement type airflow pulverizer and used for classifying powder materials finely pulverized by the pulverizer. Although a proposal has been made, a typical one is a dispersion separator (manufactured by Nippon Pneumatic Industries, Ltd.) as shown in FIG. As an outline, the powder material introduced from the powder supply cylinder together with the conveying air is:
At the bottom thereof, a central portion is introduced into a classifying chamber 250 provided with a high graded classifying plate 200, and in the classifying chamber 250, the powder material is swirled by an airflow that flows together, and is passed through a classifying louver 290. Then, the fine powder is centrifuged into fine powder and coarse powder, and the fine powder is discharged from a fine powder discharge chute 220 provided at the center of the classification plate 200.
Is discharged from a coarse powder discharge port 210 provided on the outer peripheral portion of the main body.

However, such a conventional air classifier has the following problems. That is, as shown in FIG. 10, the powder material supply section to the classifying chamber 250 of this type of airflow classifier has a cyclone-like shape, and a guide tube 254 is provided at the center of the upper surface of the upper cover 260. Are provided in an upright state, and a powder supply cylinder 280 is connected to the upper outer peripheral surface of the guide cylinder 254. The powder material supplied through the powder supply cylinder 280 The powder supply cylinder 280 is guided by the guide cylinder 254 so as to be introduced in the tangential direction of the inner circumference.
Connected to the top. Therefore, when the powder material is supplied from the powder supply cylinder 280 into the guide cylinder 254, the powder material falls while rotating along the inner peripheral surface of the guide cylinder 254. In this case, since the powder material falls from the powder supply tube 280 in a belt shape along the inner peripheral surface of the guide tube 254, the classification chamber 2
The distribution and concentration of the powder material flowing into the pipe 50 become non-uniform, that is, the powder material flows into the classifying chamber 250 only from a part of the inner peripheral surface of the guide cylinder 254, There is a problem that dispersion is poor. In addition, if an attempt is made to increase the processing amount and increase the processing efficiency, agglomeration of the powder material is more likely to occur and the dispersion is not sufficiently performed, so that there is a problem that high-precision classification cannot be performed.

On the other hand, in recent years, along with high image quality, high definition, and energy saving measures of copiers and printers, the particle size of toner as a developer has become smaller, and a toner having a sharp particle size distribution has been demanded. Further, as a binder resin used as a constituent material of the toner, a resin having a low melting point, a low softening point, and a low glass transition point is used. For this reason, in order to achieve a reduction in toner particle size by the conventional toner manufacturing method of performing the above-described pulverization and classification, first, the processing efficiency of the classification means in the first classification step is poor, and the first classification step is performed. Since the pulverization efficiency of the air-flow type fine pulverizer for finely pulverizing the coarse powder classified in the step (1) is poor, dispersion failure and agglomeration in the first classifying means become large, and high-precision classification cannot be performed. The particle size distribution of the toner supplied to the second classifying means becomes broad, and the classification yield of the classified product obtained by the second classifying means is reduced, so that the toner product having a small particle size and a sharp particle size distribution can be efficiently produced. There was a problem that it could not be obtained well.

The binder resin used as a constituent material of the toner is a resin having a low melting point, a low softening point and a low glass transition point. Local flow near the surface causes problems such as fusion, coarsening, and aggregation of the toner, and there is a problem that a high quality toner product cannot be obtained.

[0012]

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a method of manufacturing a toner for developing an electrostatic image, which solves the above-mentioned various problems in the prior art. . It is a further object of the present invention to provide a method for efficiently producing an electrostatic image developing toner having a fine particle size distribution with a small particle size. That is, the present invention melts and kneads a mixture containing a binder resin, a colorant and an additive, cools the melt-kneaded product, and then refines a predetermined material from a powder material composed of solid particles formed by coarse pulverization. It is an object of the present invention to provide a method for efficiently producing a particle product having a particle size distribution (used as a toner) with a high yield. In particular, an object of the present invention is to provide a weight average particle size of 10 μm.
An object of the present invention is to provide a toner manufacturing method capable of efficiently manufacturing a toner for developing an electrostatic image having a small and sharp particle size distribution having a particle size of not more than m and not more than 7 μm.

[0013]

The above object is achieved by the present invention described below. That is, the present invention relates to a method comprising melting and kneading a mixture containing at least a binder resin and a colorant, cooling the obtained kneaded material, and then pulverizing the coarsely pulverized product obtained by pulverizing the cooled product by a pulverizing means. First, the raw material is introduced into a first classification step using a rotary airflow classification means having a horizontal rotary rotor to classify fine powder and coarse powder, and then the fine powder classified in the first classification step is classified into a first powder. Introduced into the 2 classification process to further classify to obtain a classified product for producing toner, and the coarse powder classified in the 1st classification process is introduced into a mechanical pulverizer as a material to be pulverized and finely pulverized. In the method for producing a toner in which the finely pulverized material is mixed into the powder raw material and introduced into the first classifying step to carry out a circulation process, at least a rotor including a rotating body attached to a central rotating shaft is provided. , While maintaining a constant interval S with the rotor surface, And the annular space formed by maintaining the interval S is configured to maintain an airtight state. This is a method for producing a toner, characterized in that the object to be ground is finely ground by introducing and rotating the rotor at a high speed.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be specifically described below with reference to the accompanying drawings. FIG.
Is an example of a flowchart showing an outline of the method for producing a toner of the present invention. In the method for producing a toner of the present invention, a mixture containing at least a binder resin and a colorant is melt-kneaded, and the obtained kneading is performed. After cooling the product, the coarsely pulverized product obtained by pulverizing the cooled product by a pulverizing means is used as a powder raw material. Then, first, the powder raw material is classified into coarse powder and fine powder in a first classification step, and the fine powder classified in the first classification step is further classified into a second classification means in a second classification step (for example, FIG. (3 divided classifier as shown) to obtain a classified product (intermediate powder) to be a toner product. The feature of the method for producing the toner of the present invention is that the first classifying step includes the following steps.
A rotary airflow classifier having a horizontal rotating rotor is used as a classification means, and the coarse powder classified by the first classification means is further finely pulverized by a pulverization means, and is again introduced into the first classification means and circulated. It is to use a specific mechanical pulverizer as a fine pulverizing means at the time of processing. That is, according to the above configuration, when the rotor of the mechanical pulverizer is rotated at a high speed, the material to be pulverized passes through the space S between the rotor and the stator arranged around the rotor. Due to the shearing force and collision force generated at the time of crushing, the object to be crushed is pulverized very efficiently,
Since the finely pulverized product is introduced into a rotary airflow classifier having an efficient horizontal rotating rotor and classified, the fine powder introduced into the second classification step has a sharp particle size distribution. As a result, it is possible to perform fine classification in the fine particle region in the second classification step.

In a preferred embodiment of the present invention, a rotary airflow classifier, which is a first classifying means in the first classifying step, has a plurality of blades arranged at regular intervals on the same circumference, Are arranged so as to form a fixed angle θ with respect to a straight line connecting the center of the rotating rotor and the tip of the blade, and the diameter L ₁ of the horizontal rotating rotor is 100 to 1,000 mm. , The blade length L ₂ is 10 to 10
0 mm, and the angle θ between the straight line connecting the center of the rotating rotor and the tip of the blade and the blade is 20 ° to 90 °. If a rotary airflow classifier having such a structure is used, the powder material, which is the toner material introduced into the rotary airflow classifier, is uniformly dispersed by the forced vortex generated by the horizontal rotary rotor, Even if the processing amount is increased, the ultrafine particles do not agglomerate in the classifier, and it is possible to classify the finely pulverized powder raw material for toner production having a small particle size with high accuracy. In particular, the horizontal type rotating rotor having the above-described structure is used in a range of 1,000 to 8,000.
When rotating and classifying by rotating at rpm, the peripheral speed of the rotating rotor and the inclination of the blades are optimized, which makes it possible to generate a forced eddy current efficiently and more specifically with low energy. Fine classification in the diameter region is possible.

As described above, in the present invention, by using the above-described rotary airflow classifying means as the first classifying means and the specific mechanical pulverizing means in the pulverizing section, the classifying efficiency and the pulverizing efficiency in the first classifying step are obtained. Is significantly improved, the supply amount to the first classifying unit does not increase even if the toner particle size is reduced, and even if the supply amount of the powder raw material to the first classifying unit increases. However, due to the effect of the forced vortex of the rotary airflow classifier, high-precision classification without causing toner aggregation in the classifier becomes possible. As a result, the particle size distribution of the fine powder supplied to the second classification means becomes sharp, and the yield of the classified product as the toner product classified by the second classification means can be remarkably improved. It is possible to improve the efficiency of the entire flow shown in FIG.
That is, according to the toner production method of the present invention, by controlling the classification and pulverization conditions, a toner having a small and sharp particle size distribution with a weight average particle size of 10 μm or less, more preferably 7 μm or less is obtained. It can be manufactured efficiently.

Hereinafter, the toner production method of the present invention will be described more specifically with reference to the accompanying drawings. FIG. 2 shows an example of an apparatus system according to the toner manufacturing method of the present invention having the above configuration. In this apparatus system, a powder raw material containing at least a binder resin and a colorant, which are toner materials, is first introduced into a first classifying means 22 via a first fixed supply device 21 to remove coarse powder and fine powder. Classified into The classified fine powder is sent to the second quantitative feeder 24 via the collection cyclone 23, and then introduced into the second classification means via the vibration feeder 25. On the other hand, the coarse powder classified by the first classification means 22 is sent to the pulverizer 28 and finely pulverized, and then is again introduced into the first classification means 22 together with the newly charged powder raw material to be circulated. .

As the first classifier used in the present invention, a rotary airflow classifier having a horizontal rotary rotor for classifying by a centrifugal force using a forced vortex is used. For example, Hosokawa Micron's teaplex (AT
P) Classifier and the like. Preferably, if a rotary airflow classifier having a horizontal rotary rotor as shown in FIGS. 3 and 4 is used, the classification accuracy of fine powder and coarse powder can be improved. FIG. 3 shows an overall view of the airflow classifier,
FIG. 4 shows a partial enlarged view and an enlarged side view of a horizontal rotary rotor (classification rotor) 124 of the airflow classifier.

In FIG. 3, reference numeral 121 denotes a cylindrical main body casing. A classification chamber 122 is formed inside the main body casing 121, and a guide chamber 123 is provided below the classification chamber 122. The rotary airflow classifier shown in FIG. 3 is of an individual drive type, and generates a forced vortex using centrifugal force in the classification chamber 122 to classify it into coarse powder and fine powder.
A classifying rotor 124 is provided in the classifying chamber 122, and by rotating the classifying rotor 124, air is sucked from between the classifying rotors 124 and the powder raw material 42 and the air sent to the guide chamber 123 are separated from each other. 122. The powder raw material 42 is supplied from the raw material input port 125, and air is taken in together with the powder raw material 42 from the input port 126 and further from the raw material input port 125. The powder raw material 42
It is conveyed from the guide chamber 123 to the classification chamber 122 via a rotary valve or together with the incoming air. In addition, input port 1
It is preferable to uniformly distribute the air flowing through the guide chamber 123 through the guide chamber 123 and the powder raw material 42 between the classification rotors 124 in order to achieve accurate classification.
Further, it is necessary that the flow path to reach the classification rotor 124 has a shape in which the concentration of the powder raw material 42 does not easily occur.
The raw material inlet 125 is not limited to the position shown in FIG.

The classifying rotor 124, which is a component of the classifier, has a plurality of blades arranged at regular intervals on the same circumference as shown in FIG. Are arranged so as to form a fixed angle θ with respect to a straight line connecting the tip of the lens. The size of the classifying rotor 124 depends on the size of the classifier main body.
24 of a diameter L ₁ is 100～1,000Mm, the range length L ₂ of the blade is 10 to 100 mm, and the angle of the blades of the classifying rotor 124 is a movable, classifying rotor 1
It is preferable that the angle .theta. Between the straight line connecting the center of the blade 24 and the tip of the blade and the blade is designed to be arbitrarily changed within a numerical range of 20 to 90 degrees. The speed control of the classifying rotor 124 having such a shape is performed through a frequency converter 128.

In the present invention, the classification rotor 124
The angle θ formed by the straight line connecting the center of the blade and the tip of the blade and the blade indicates the angle ABC formed by the straight line OA and the straight line BC, as shown in FIG. If the angle θ is smaller than 20 °, it is difficult to generate a strong forced vortex, and even if a forced vortex can be generated, high-speed rotation of the classifying rotor 124 is required, and stable and safe operation is performed. Is difficult to maintain, which is not preferable. The more preferable range of the angle θ is 3
It is 5 to 65 °, and by doing so, a strong forced vortex can be efficiently generated in the classification chamber 122.

The fine powder discharge pipe 129 is connected to a suction fan 131 through a fine powder collecting means 130 such as a cyclone or a dust collector.
By operating the suction fan 131, a suction force is applied to the classifying chamber 122 to generate a forced vortex.

In the method for producing a toner according to the present invention, the air classifier used as the first classifier has the above-mentioned structure. The sample to be classified is introduced into the classifier by a raw material inlet located at the lower part of the classifier. From 125. That is, pulverized material finely pulverized by a mechanical pulverizer described later, air used for pulverization, and air containing newly supplied powder material are introduced into the guide chamber 123 from the material input port 125. Then, it flows between the classifying rotors 124 from the guide room 123.

The powder raw material that has flowed into the classification chamber 122 is sufficiently dispersed in the classification chamber 122 in which the forced vortex is generated by the classification rotor 124 rotating at a high speed, and the centrifugal force acting on each particle by the forced vortex. Is centrifuged into coarse powder and fine powder. The coarse powder in the classification chamber 122 is supplied to the coarse powder discharging hopper 1 connected to the lower part of the main body casing.
32 through, after being comminuted is supplied to the material to be ground feed pipe 41 of the mechanical pulverizer will be described later via the rotary valve 133, pulverized material is introduced into the first classifying means again of the circulating It is processed. On the other hand, the fine powder classified by the first classification means enters the fine powder discharge pipe 129 between the classification rotors 124, is discharged to the fine powder collection means 130, and is introduced into the second classification means.

As described above, in the toner production method of the present invention,
A rotary airflow classifier that generates a forced vortex by rotating a horizontal rotary rotor having an angle θ between a straight line connecting the center of the classifying rotor 124 and the tip of the blade and the blade in the range of 20 ° to 90 °. , It is preferable to classify the powder raw material, further, the number of rotations of the classification rotor 124, 1,
It is more preferable to perform classification at 000 to 8,000 rpm. When the horizontal rotary rotor having the above structure is rotated at such a high speed, the classification chamber 1
Due to the forced vortex generated in the inside 22, the powder raw material is uniformly and satisfactorily dispersed. As a result, even if the processing amount increases, high-precision classification can be performed without causing aggregation of the fine particles. In particular, when the rotary airflow classifier having the above configuration is operated with the above rotation, the peripheral speed of the rotating classification rotor 124 and the inclination of the blades are optimized, so that it is efficient and detailed. It is possible to generate a forced vortex with low energy. As a result, for example, it is impossible to classify a large amount of toner having a small particle diameter with high accuracy, which is not possible by a conventional classification method using a gas flow classifier as shown in FIG. Becomes possible.

In the rotary air classifier as described above, the classification point is determined by the number of revolutions of the classification rotor. However, conventionally, the efficiency of the pulverizing means of the pulverizer connected to the classifier is not good. It is difficult to obtain a toner having a small diameter with a classifier, and even if it is obtained, a great deal of labor is required. However, in the present invention, as a result of using a mechanical pulverizer as shown in FIG. 5 described later as the pulverizing means, the pulverization performance is improved, and the coarse powder is efficiently atomized. By introducing the finely pulverized product into a rotary airflow classifier, which is a first classifying means, fine classification in the fine particle region becomes possible. Further, the rotary classifier used in the present invention has an advantage that the classification point can be easily changed only by changing the rotation speed of the classification rotor, and the operability is excellent.

The rotation speed of the classifying rotor 124 is 1,000
If it is less than 0 rpm, generation of forced vortex in the classification chamber 122 is not efficiently performed, and dispersion and classification of the powder material are not sufficiently performed, which is not preferable. On the other hand, if the rotation speed exceeds 8,000 rpm, it is difficult to maintain stable and safe operation, which is not preferable.

As the pulverizing means used in the present invention, for example, a mechanical pulverizer having the structure shown in FIGS. 5 to 8 is used. FIG. 5 is a sectional view of a main part of the mechanical crusher,
FIG. 6 is a sectional view taken along the line AA ′ in FIG. FIG. 7 is a perspective view showing a surface portion of a stator which is a component of the mechanical crusher, and FIG. 8 is a perspective view showing a surface portion of a rotor which is a component of the mechanical crusher.

The mechanical pulverizer used in the present invention will be described below with reference to FIGS. As shown in FIG. 5, the mechanical pulverizer used in the present invention is disposed around an axis C, and is configured to be rotatable with the rotation of the axis C. Some rotor 43
And a stator 44 having a cylindrical inner surface shape provided facing the surface of the stator 44. As shown in FIG. 6, the rotor 43 and the stator 44 are arranged such that their opposing surfaces have a predetermined gap S therebetween. That is, in the device, a rotor 43 composed of a cylindrical rotating body as shown in FIG. 8 is provided inside a stationary stator 44 having a cylindrical shape as shown in FIG. However, they are arranged so as to have a predetermined interval S between the surfaces thereof. Although the axis C is a vertical axis in the example shown in FIG. 5, the mechanical crusher used in the present invention is not limited to this, and these are rotated by 90 °, and the axis C becomes a horizontal axis. Configuration may be used.

As shown in FIG. 5, the upper, lower, left and right end surfaces of the cylindrical rotor 43 are closed by an upper plate 48 and a lower plate 49, respectively. Further, the rotor 43 is configured to be rotatable via a drive belt 50 by a drive motor (not shown) which is supported by a base 45 of the mechanical pulverizer. The upper and lower ends of the stator 44 are
The upper casing 51 and the lower casing 52 provided at an interval from the upper surface plate 48 and the lower surface plate 49, respectively, are attached in an airtight manner.
Space 54 surrounded by lower plate 49 and lower casing 52
Is connected to a supply pipe 41 for the material to be pulverized, while a discharge port 55 for the pulverized material is provided in a space surrounded by the upper plate 48 and the upper casing 51.

Accordingly, while the rotor 43 is rotated at a high speed by the drive motor via the drive belt 50, the pulverized material obtained by coarsely pulverizing the melt-kneaded toner material into the raw material supply port 46 shown in FIG. The powder raw material 42 is first classified into fine powder and coarse powder by the first classification means together with the compressed air supplied from the high-pressure gas supply port 47, and then classified. The coarse powder is formed between the surface of the rotor 43 and the surface of the stator 44 from the supply pipe 41 of the mechanical pulverizer shown in FIG. Into the annular space 53. And the powder raw material 42 is a rotor 43 rotating at high speed.
Is accelerated in the circumferential direction by the rotor 43 and the stator 4
While being finely pulverized by the shearing force and collision of No. 4, it moves to the upper part of the pulverizer on the ascending airflow and is discharged out of the system through the discharge port 55. 5 to 8 show an example of a mechanical crusher in which the axis direction of the axis C to which the rotor 43 is attached is vertical, but the arrangement direction of the axis C is vertical as shown in FIG. It is not limited to a direction, and may be arranged in a horizontal direction or the like.

As described above, in the method for producing a toner according to the present invention, since the mechanical pulverizer having the above-described configuration is used, the ring formed between the rotor 43 and the stator 44 is formed. When the powder raw material 42 is introduced into the space 53, the powder raw material 42 can be pulverized very efficiently by the large shearing force and collision force generated in the annular space 53.
Further, in the present invention, the respective surfaces of the rotor 43 and the stator 44 described above are made of a material such as a strong ceramic, for example, so that wear of the constituent members of the crusher can be reduced over a long period of time. Since it can be prevented, the life of the crusher can be prolonged, and stable operation can be performed.

[0033] In the toner manufacturing method of the present invention, as described above, the first classifying means to use in the first classification step,
A rotary airflow classifier that does not cause agglomeration of fine powder with good classification efficiency shown in FIGS. 3 and 4 and a mechanical pulverizer with good grinding efficiency shown in FIGS. 5 and 8 are used in combination. As a result, the pulverizing efficiency of the pulverizer is improved as compared with the prior art, and the load on the first classifying means does not increase even when the toner is miniaturized. Further, due to the increase in the dust concentration, toner aggregation which occurs when a conventional classifier / pulverizer is used is suppressed, and highly accurate classification can be performed. As a result, the fines supplied to the second frequency Kyute <br/> stage of the second classification step subsequent to the first classification step, and what was to be can classified into high precision toner aggregation was suppressed Therefore, as the classified product obtained in the second classification step, a high-quality product having a small particle size and a sharp particle size distribution is obtained, and the classification yield by the second classification means is also greatly improved.

Further, even if the supply amount of the powdery raw material of the toner is increased and the load on the first classifier is increased, in the present invention, a rotary airflow classifier is used for the classifier, more preferably. Since the horizontal rotating rotor of the rotary airflow classifier, in which the peripheral speed of the classifying rotor 124 and the inclination of the blades are optimized, is used, an efficient forced vortex is generated in the classifying chamber and the powder for toner production is produced. The body material can be uniformly dispersed, and high-precision classification can be performed without causing aggregation. As a result, a classified product (fine powder) having a small particle size and a sharp particle size distribution can be supplied to the second classifying means. For this reason, the classification yield of the classification by the second classification means is greatly improved. That is, according to the present invention, it is possible to obtain a toner having a small particle diameter and a sharp particle size distribution having a weight average diameter of 10 μm or less, and more preferably 7 μm or less.

In the toner production method of the present invention, as described above, a classified product (fine powder) having a small particle size and a sharp particle size distribution is supplied to the second classifying means by the first classifying step and the pulverizing step. As a result, efficient classification can be performed in the second classification step, and any known method may be used as the second classification means. Preferably, the second
As a classification means, at least a coarse powder region (first fractionation region),
A multi-division classification area having a middle powder area (second fractionation area) and a fine powder area (third fractionation area) is used. For example, FIG.
2 (cross-sectional view) is a multi-segmentation classifier as one of the specific examples. More specifically, classification using the Coanda effect having a Coanda block such as an elbow jet manufactured by Nippon Steel Mining Co., Ltd. Means.

The classification chamber having such a classification area is mainly composed of side walls 141 and 142 having a shape as shown in FIG.
Lower walls 143 and 144 and Coanda block 145
Consists of The lower walls 143 and 144 are provided with knife-edge type classification edges 146 and 147, respectively, by which the classification zone is divided into three. At the lower part of the side wall 141, there are provided raw material supply pipes 148 and 149 which open to the classification chamber, and a Coanda block 145 which is bent downward in the direction of extension of the tangent at the bottom of the supply pipe to form an elliptical arc is provided. I have. or,
The upper wall 150 of the classifying chamber is provided with a knife-edge type inlet edge 151 directed toward the lower part of the classifying chamber. Further, the upper part of the classifying chamber is provided with air inlet pipes 152 and 153 that open to the classifying chamber. The inlet pipes 152 and 153 are provided with gas introduction adjusting means 154 and 155 such as dampers, and static pressure gauges 156 and 157, respectively. Classification edge 1
The positions of 46 and 147 and the inlet edge 151 differ depending on the type of the raw material to be classified and the desired particle size. Further, the outlets 158, 159, and 16 that open into the classification chamber are provided on the bottom of the classification chamber so as to correspond to the respective separation areas.
0 is provided. The outlets 158, 159 and 160 may be provided with opening and closing means such as valve means, respectively.

The raw material supply pipe is preferably composed of a cylindrical raw material supply pipe 148 and a pyramid-shaped cylindrical raw material supply pipe 149, and the inner diameter of the raw material supply pipe 148 and the narrowest part of the raw material supply pipe 149. When the ratio of the inner diameters is set to 20: 1 to 1: 1, preferably 10: 1 to 2: 1, a good insertion speed can be obtained. As a means for introducing the powdered raw material to be classified into the supply pipe together with the air flow, a method of applying a pressure of 0.1 to 3 kg / cm ² is applied, and a blower located downstream of the classification zone is enlarged to reduce the load of the classification zone. A method of naturally aspirating the outside air and the powder raw material by increasing the pressure, or a method of attaching an injection feeder to the raw material powder input port, thereby sucking the raw material powder and the outside air and sending it to the classification zone via the supply pipe. Etc.

In the present invention, among the above-mentioned charging means,
In particular, it is advantageous and preferable to use a method in which the negative pressure in the classification zone is increased and the outside air and the powder raw material are naturally suctioned, or a method using an injection feeder is used in terms of equipment and operating conditions. Further, the classification of the toner for developing an electrostatic charge image, which requires high-precision classification, can be performed more effectively, and a favorable effect can be obtained in the classification of the toner having a weight average particle diameter of 10 μm or less. In particular, in the classification of toner having a weight average particle diameter of 7 μm or less, further effects can be obtained.

The classification operation in the multi-division classification region having the above-described configuration is performed, for example, as follows. That is, the pressure in the classification area is reduced through at least one of the outlets 158, 159 and 160, and the raw material powder is supplied to the raw material supply pipes 148 and 149 at a flow rate of 50 m / sec to 300 m / sec by an air flow flowing by the reduced pressure. To the classification area via
That is, if the first fine powder is supplied to the classification area at a flow rate of less than 50 m / sec, it is difficult to sufficiently loosen the aggregation of the fine powder, and it is easy to cause a decrease in classification yield and classification accuracy.
Not preferred. When the first fine powder is supplied to the classification region at a flow rate exceeding 300 m / sec, the particles tend to be pulverized due to collision between the particles and ultrafine particles are easily generated, which tends to cause a decrease in the classification yield. Absent.

By the means described above, the powdered raw material composed of the first fine powder obtained in the first classifying step is supplied with the Coanda effect by the action of the Coanda block 145 and the action of gas such as air flowing in at that time. In accordance with the size of each particle size, large particles (particles having a particle size exceeding the specified particle size) move outside the airflow, that is, the first fractionation area outside the classification edge 147. In the meantime, the intermediate particles (particles within the standard size) are the second particles between the classification edges 146 and 147.
In the fractionation area, small particles (particles smaller than the standard particle size) are divided into third fractionation areas inside the classification edge 146, and large particles (coarse powder) are discharged from the outlet 158 to intermediate particles (medium powder). The body is discharged from the outlet 159, and the small particles (fine powder) are discharged from the outlet 160.

In order to carry out the above-described method, the above-described devices are connected to each other by a communication means such as a pipe, and used as an integrated device system as shown in FIG. That is, the classifier 27 in the apparatus system shown in FIG. 2 is as shown in FIG. 12, and the vibration feeder 25 and the collecting cyclones 29, 30 and 31 are connected to each other by communication means.

When the powder material is introduced into the multi-segment classifier 27 as described above, the powder material is introduced into the three-segment classifier 27 at a flow rate of 50 m / sec to 300 m / sec. The size of the classification area of the multi-segment classifier 27 is usually (10 to 50 cm) ×
(10-50cm), so the crushed material is 0.1-0.01
In seconds, it can be classified into three or more particle groups. And 3
By the classifier 27, large particles (particles exceeding a specified particle size: coarse powder), intermediate particles (particles having a specified internal particle size: medium powder), and small particles (particles smaller than the specified particle size: fine powder) ). Thereafter, the coarse powder is discharged from the discharge conduit 158.
, And is sent to the collecting cyclone 29 and returned to the crusher 28. The intermediate powder is discharged out of the system via a discharge conduit 159, collected by the collection cyclone 31, and collected as a toner product 33. The fine powder is discharged out of the system via the discharge conduit 160, collected by the collection cyclone 30, and then collected as the fine powder 34 having an irregular particle diameter. The collection cyclones 29, 30 and 31 use the nozzle 14
It can also function as a suction pressure reducing means for sucking and introducing the classification area through 8 and 149. Further, the coarse powder classified at this time may be returned to the pulverizer 28 or may be returned to the first constant supply device 21. In order to reduce the load on the first classifier 22 and reliably perform the pulverization by the pulverizer 28, it is more preferable to return the coarse powder directly to the pulverizer 28.

The toner production method of the present invention can be preferably used for producing toner particles used for developing an electrostatic image. To prepare an electrostatic image developing toner, a mixture containing at least a binder resin and a colorant is used as a material, and in addition, a magnetic powder, a charge control agent, and other additives may be used as necessary. Used.
As the binder resin, vinyl-based and non-vinyl-based thermoplastic resins are preferably used. These materials were thoroughly mixed by a mixer such as a Henschel mixer or a ball mill, and then melted, kneaded and kneaded using a hot kneader such as a roll, kneader, and extruder to make the resins compatible with each other. The toner can be obtained by dispersing or dissolving the pigment or dye therein, solidifying by cooling, and then pulverizing and classifying. In the present invention, the pulverizing step and the classifying step are performed by using the apparatus having the above-described configuration. Use the system.

Hereinafter, the constituent materials of the toner will be described. When a heat and pressure fixing device or a heat and pressure roller fixing device having a device for applying oil is used as the binder resin used for the toner, the following binder resins for toner can be used. For example, polystyrene, poly-p
A homopolymer of styrene such as chlorostyrene and polyvinyltoluene and a substituted product thereof; a styrene-p-chlorostyrene copolymer, a styrene-vinyltoluene copolymer, a styrene-vinylnaphthalene copolymer, and a styrene-acrylate ester copolymer. Polymer, styrene-methacrylic acid ester copolymer, styrene-α-chloromethacrylic copolymer,
Styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene- Styrene-based copolymers such as acrylonitrile-indene copolymer; polyvinyl chloride, phenolic resin, natural resin-modified phenolic resin, natural resin-modified maleic resin, acrylic resin, methacrylic resin,
Examples include polyvinyl acetate, silicone resin, polyester resin, polyurethane, polyamide resin, furan resin, epoxy resin, xylene resin, polyvinyl butyral, terpene resin, coumaroindene resin, and petroleum resin.

In the heat and pressure fixing method or the heat and pressure roller fixing method in which little or no oil is applied, a so-called offset phenomenon in which a part of a toner image on a toner image support member is transferred to a roller, Further, the adhesion of the toner to the toner image supporting member is an important problem.
Since the toner which is fixed with less heat energy has a property of easily blocking or caking during storage or in a developing device, these problems must be considered at the same time. The physical properties of the binder resin in the toner are most significantly involved in these phenomena. However, according to a study conducted by the present inventors, when the content of the magnetic material in the toner is reduced, the toner image is not supported during fixing. Although the adhesion of the toner to the body is improved, offset tends to occur, and blocking or caking tends to occur. Therefore, when using a heat and pressure roller fixing method in which almost no oil is applied, selection of a binder resin is more important. Preferred binder resins include, for example, a crosslinked styrene copolymer or a crosslinked polyester.

Examples of comonomers for the styrene monomer of the styrene copolymer include acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, and the like.
Dodecyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, acrylonitrile, methacrylic nitrile, two such as acrylamide Monocarboxylic acid having a heavy bond or a substituted product thereof; for example, dicarboxylic acid having a double bond such as maleic acid, butyl maleate, methyl maleate, dimethyl maleate and the like; and substituted products thereof; for example, vinyl chloride, acetic acid Vinyl esters such as vinyl and vinyl benzoate; vinyl ketones such as vinyl methyl ketone and vinyl hexyl ketone; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl isobutyl ether ; Vinyl monomers such as may be used singly or two or more.

As the cross-linking agent, compounds having two or more polymerizable double bonds are mainly used, for example, aromatic divinyl compounds such as divinylbenzene, divinylnaphthalene and the like; ethylene glycol diacrylate, Ethylene glycol dimethacrylate,
Carboxylic acid esters having two double bonds such as 1,3-butanediol dimethacrylate; for example, divinylaniline, divinylether, divinylsulfide,
A divinyl compound such as divinyl sulfone; and a compound having three or more vinyl groups; and the like are used alone or as a mixture.

When the pressure fixing method or the light heat pressure fixing method is used, a binder resin for a pressure fixing toner can be used.
Polymethylene, polyurethane elastomer, ethylene-
Examples include an ethyl acrylate copolymer, an ethylene-vinyl acetate copolymer, an ionomer resin, a styrene-butadiene copolymer, a styrene-isoprene copolymer, a linear saturated polyester, and paraffin.

It is preferable that a charge control agent is mixed (internally added) to the toner particles. The charge control agent makes it possible to control the optimal charge amount according to the development system. In particular, in the present invention, the balance between the particle size distribution and the charge can be further stabilized, and the charge control agent is used. As a result, it is possible to further clarify the function separation and mutual capture for higher image quality for each particle size range described above. As the positive charge control agent, for example, denatured products such as nigrosine and fatty acid metal salts; quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate and tetrabutylammonium tetrafluoroborate; Or two or more types can be used in combination. Among them, charge control agents such as nigrosine compounds and quaternary ammonium salts are particularly preferably used. Further, a homopolymer of a monomer represented by the following general formula (1) or a copolymer with a polymerizable monomer such as styrene, acrylate and methacrylate as described above is used as a positive charge control agent. Can be used as
In this case, these charge control agents also function as (all or part of) the binder resin.

General formula (1) R ₁ : H, CH ₃ , R ₂ , R ₃ : a substituted or unsubstituted alkyl group (preferably C
_{1 ~C 4),}

As the negative charge control agent, for example, organometallic complexes and chelate compounds are effective, and examples thereof include aluminum acetylacetonate, iron (II) acetylacetonate, and chromium 3,5-ditert-butylsalicylate. Or zinc or the like, particularly preferably an acetylacetone metal complex, a salicylic acid-based metal complex or a salt thereof, and particularly preferably a salicylic acid-based metal complex or a salicylic acid-based metal salt.

The above-mentioned charge control agent (having no action as a binder resin) is preferably used in the form of fine particles. In this case, the number average particle size of the charge control agent is
Specifically, it is preferably 4 μm or less (more preferably 3 μm or less). When internally added to the toner, such a charge control agent is preferably used in an amount of 0.1 to 20 parts by weight (more preferably 0.2 to 10 parts by weight) based on 100 parts by weight of the binder resin.

When the toner is a magnetic toner, examples of the magnetic material contained in the magnetic toner include iron oxides such as magnetite, γ-iron oxide, ferrite, and iron-rich ferrite; and iron, cobalt, and nickel. Metals or alloys of these metals with metals such as aluminum, cobalt, copper, lead, magnesium, tin, zinc, antimony, beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, vanadium and mixtures thereof Is mentioned. These ferromagnetic materials have an average particle size of 0.1 to 1 μm, preferably 0.1 to 0.5 μm.
The amount contained in the magnetic toner is preferably from 60 to 110 parts by weight per 100 parts by weight of the resin component, and more preferably from 65 to 10 parts by weight based on 100 parts by weight of the resin component.
0 parts by weight.

As a coloring agent used in the toner, conventionally known dyes and / or pigments can be used. Examples include carbon black, phthalocyanine blue, peacock blue, permanent red, lake red, rhodamine lake, Hanser yellow, permanent yellow, benzidine yellow and the like. The content is 0.1 to 100 parts of the binder resin.
20 parts by weight, preferably 0.5 to 20 parts by weight, and more preferably 12 parts by weight or less, more preferably 0.5 to 20 parts by weight, in order to improve the transparency of the OHP film on which the toner image is fixed.
9 parts by weight is good.

As described above, according to the present invention,
A toner having a sharp particle size distribution can be obtained from a toner raw material having a weight average particle size of 10 μm or less, and a sharp particle size distribution can be obtained particularly from a toner raw material having a weight average particle size of 7 μm or less.

[0056]

Next, the present invention will be described in more detail with reference to examples and comparative examples of the present invention. Example 1 100 parts by weight of styrene-butyl acrylate-divinylbenzene copolymer (monomer polymerization weight ratio: 80.0 / 19.0 / 1.0, weight average molecular weight = 350,000) Magnetic iron oxide (average particle size: 0) .18 μm) 100 parts by weight Nigrosine 2 parts by weight Low-molecular-weight ethylene-propylene copolymer 4 parts by weight The above formulation was mixed with a Henschel mixer (FM-75).
The mixture was well mixed with a mold and 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 to 1 mm or less with a hammer mill to obtain a coarsely pulverized material as a powder raw material for toner production.

The obtained toner raw material was pulverized and classified by an apparatus system shown in FIG. The mechanical crusher 28 includes:
Using the device having the configuration shown in FIG.
It was operated at a rotation speed of 5200 rpm using a 00 mm one. As the first classifying means 22, a rotary airflow classifier having the structure shown in FIGS. 3 and 4 was used. Classification rotor 12
4 diameter L ₁ is 200 mm, the length L ₂ of the blades of the classifying rotor 124 is 30 mm, connecting the tip of the center and the blades of the classifying rotor 124 lines and the angle θ of the blade 45
° and used. The number of revolutions of the classifying rotor 124 was 2500 rpm.

In this embodiment, 35.0 kg of the powdery raw material composed of the coarsely pulverized material is weighed by the table-type first constant-quantity feeder 21.
At the rate of / h, the mixture was supplied to the rotary airflow classifier 22 having the configuration shown in FIG. 3 through the supply pipe 125 by the injection feeder 35, and classified into fine powder and coarse powder. Next, the coarse powder classified by the classifier is discharged into a coarse powder discharge hopper 13.
2 through a mechanical pulverizer 2 having the configuration shown in FIG.
8 was introduced. Crusher 28 from supply pipe 41
The supply of the powder raw material to the container is performed under a pressure of 3.0 kg / cm ² (G),
The test was performed using 1.0 Nm ³ / min compressed air. While being mixed with the powdered raw material for producing the pulverized toner, the mixture was again introduced into the airflow classifier 22 and circulated to perform closed-circuit pulverization.
On the other hand, the fine powder classified by the rotary airflow classifier 22 is collected by the cyclone 23 while being accompanied by the suction air from the exhaust fan 131, and is introduced into the second quantitative feeder 24. At this time, the fine powder obtained by classification by the first classification means had a weight average diameter of 7.1 μm and a particle diameter of 4.0 μm.
m had a sharp particle size distribution containing 45% by number of particles and 3.0% by volume of particles having a particle size of 10.8 μm or more.

Next, the fine powder obtained by the classification by the above-mentioned first classification means is introduced into the second quantitative feeder 24, and the fine powder is passed through the vibration feeder 25 and the nozzles 148 and 149.
It was introduced at a rate of 0.0 kg / h into a three-division classifier 27 having the configuration of FIG. 12 in the second classification step. In the classifier 27, the powder is classified into three kinds of particle sizes of a coarse powder, a medium powder and a fine powder by utilizing the Coanda effect. At the time of introduction into the multi-segmentation classifier 27, the suction force derived from the pressure reduction in the system by the suction pressure reduction of the collection cyclones 29, 30 and 31 communicating with the discharge ports 158, 159 and 160 and the raw material supply nozzle 148 Compressed air from the installed injection 32 was utilized. The introduced fine powder was instantaneously classified into three types of coarse powder, medium powder and fine powder in 0.1 seconds or less. Among the classified materials, the coarse powder was collected by the collecting cyclone 29, introduced into the mechanical pulverizer 28 described above, and introduced again into the pulverizing step.

The intermediate powder (classified product) classified in the second classifying step has a weight average particle size of 6.9 μm, and contains 25% by number of particles having a particle size of 4.0 μm or less. 10.
It had a sharp particle size distribution containing 1.3% by volume of particles of 08 μm or more, and had excellent performance as a classified product for toner. At this time, the ratio of the amount of the intermediate powder finally obtained to the total amount of the charged powder raw materials (that is, the classification yield) was 85%.

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. That is, as a measuring device, Coulter Counter TA-II type or Coulter Multisizer II
(Both manufactured by Coulter Inc.) were used. As the electrolyte solution, about 1% NaCl aqueous solution was prepared using primary sodium chloride and used. For example, ISOTONR-II (manufactured by Coulter Scientific Japan) can be used. As a measuring method, the electrolyte solution 1
0.1 to 5 ml of a surfactant, preferably an alkylbenzene sulfonate, is added as a dispersant to 00 to 150 ml, and 2 to 20 mg of a measurement sample is further added. The electrolyte solution in which the sample was suspended was subjected to dispersion treatment for about 1 to 3 minutes with an ultrasonic
The volume distribution and the number distribution were calculated by measuring the volume and number of the toner using a μm aperture. Then, a weight-based weight average particle size determined from the volume distribution according to the present invention was determined.

Example 2 The same toner system as in Example 1 was used and pulverization and classification were performed in the same apparatus system. That is, a mechanical pulverizer having a configuration shown in FIG. 5 was used, and pulverization was performed under the same apparatus conditions as in Example 1. As the second classification means 27, the same one as in Example 1 was used. As the first classifying means, the same rotary air classifier as in Example 1 was used, but the number of revolutions of the classifying rotor was 3,100 rpm. In this embodiment,
The powdery raw material was supplied to the above-mentioned apparatus system at a rate of 32.0 kg / h, and a fine powder having a weight average particle size of 6.4 μm was obtained by the first classifying step and the pulverizing step. Next, this fine powder is
The second feed at a rate of 25.0 kg / h via the metering feeder 24
Introduced into the classification means 27, the weight average particle size is 6.1 μm,
A medium powder having a sharp particle size distribution containing 32% by number of particles having a particle size of 4.0 μm or less and 0.5% by volume of particles having a particle size of 10.08 μm or more was obtained with a classification yield of 77%. .

Example 3 The same toner system as in Example 1 was used and pulverization and classification were carried out in the same apparatus system. That is, a mechanical pulverizer having a configuration shown in FIG. 5 was used, and pulverization was performed under the same apparatus conditions as in Example 1. The second classification means 27 is also the same as in the first embodiment.
It was used for. The first classifying means 22, the diameter L ₁ of the classifying rotor 124 300 mm, the length L ₂ of the blade 35m
m, and the angle θ between the straight line connecting the center of the classifying rotor 124 and the tip of the blade and the blade is 60 °,
The number of revolutions of the classifying rotor 124 was set to 3,100 rpm. In this example, the pulverized raw material was 32.0 kg /
h and supplied to the above-mentioned apparatus system , and a fine powder having a weight average particle size of 5.9 μm was obtained by the first classification step and the pulverization step. Next, this fine powder is passed through the second
As a result of introduction into the second classifying means 27 at a rate of 5.0 kg / h, 37% by number of particles having a weight average particle diameter of 5.8 μm and a particle diameter of 4.0 μm or less are contained, and a particle diameter of 10.08 μm or more. Was obtained with a classification yield of 75%.

Example 4 100 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 (chromium salicylate complex) 4.0 parts by weight Using a Henschel mixer (FM-75)
After mixing well with a mold, Mitsui Miike Kakoki Co., Ltd.), the mixture was kneaded with a twin-screw kneader (PCM-30, manufactured by Ikegai Iron Works Co., Ltd.) set at a temperature of 100 ° C. The obtained kneaded material was cooled and coarsely pulverized to 1 mm or less with a hammer mill to obtain a coarsely pulverized material as a powder raw material for producing a toner.

Using the powder raw material obtained as described above, pulverization and classification were carried out by an apparatus system shown in FIG. As the mechanical pulverizer 28, pulverization was performed under the same apparatus conditions as in Example 1 using the apparatus having the configuration shown in FIG. As the second classification means 27, a three-division classifier similar to that of the first embodiment was used. Also, the first classification means 2
The apparatus having the same configuration as that of Example 1 was used for Example 2, except that the diameter L ₁ of the classifying rotor 124 was 200 mm, and the classifying rotor 1 was used.
24 the length L ₂ is 30mm in feather, used as θ is 45 °, 3,500r.p the rotational speed of the classifying rotor 124.
m.

In the present embodiment, 28.0 kg of the powdery raw material composed of coarsely pulverized material was
At the rate of / h, the mixture was supplied to the rotary airflow classifier 22 having the configuration shown in FIG. The coarse powder classified by the classifier is introduced into the mechanical pulverizer 28 having the configuration shown in FIG. The crusher 28
The coarse powder supplied from the crushed object supply pipe 41 has a pressure of 3.
After being pulverized using compressed air of 0 kg / cm ² (G) and 1.0 Nm ³ / min, the mixture is again mixed with the powdery raw material for toner supplied at the raw material introduction section, and then the air classifier 2 is again used.
2 and circulated to perform closed-circuit pulverization. The fine powder classified by the airflow classifier 22 is collected by the cyclone 23 while being accompanied by the suction air from the exhaust fan 131. At this time, the weight average particle size of the fine powder was 7.0 μm.

The obtained fine powder is passed through a second quantitative feeder 24.
Through the vibrating feeder 25 and the nozzles 148 and 149 at a rate of 25.0 kg / h into the second classifying means 27, and utilizing the Coanda effect to remove coarse, medium and fine powders. The powder was classified into three types, and the classified powder was used as a toner product.

The resulting classified product has a weight average particle size of 6.5 μm and a particle size of 4.0 μm or less having a particle size of 27 μm.
1.4% particles having a particle size of 10.08 μm or more containing several percent by number.
It had a sharp particle size distribution containing volume%, and had excellent performance as a classified product for toner. At this time,
The ratio of the amount of the intermediate powder finally obtained to the total amount of the charged powder raw materials (that is, the classification yield) was 80%.

Example 5 The same toner system as in Example 4 was used and pulverization and classification were performed in the same apparatus system. That is, the mechanical pulverizer having the configuration shown in FIG. 5 was used, and the second classifying means 27 used was the same as that in Example 1. As the first classifying means, a rotary airflow classifier having the same configuration as that of the fourth embodiment shown in FIG. 4 was used, but the diameter L1 of the classifying rotor 124 was 300 m.
m, the blade length L2 is 35 mm, and θ is 60 °, and the number of revolutions of the classifying rotor 124 is 3,500 rpm. p.
m. And In this embodiment, the powder raw material is 28.0.
The powder was supplied to the above-mentioned apparatus system at a rate of kg / h, and a fine powder having a weight average particle size of 6.4 μm was obtained by the first classifying step and the pulverizing step. Then, this fine powder was introduced into the second classifying means 27 at a rate of 25.0 kg / h through the second quantitative feeder 24, and as a result, the weight average particle diameter was 6.0 μm, and the particle diameter was 4.0.
containing 35% by number of particles having a particle diameter of 10.0 μm or less and having a particle diameter of 10.0
An intermediate powder having a sharp particle size distribution containing 0.2% by volume of particles of 8 μm or more was obtained with a classification yield of 76%.

Comparative Example 1 Materials having the same formulation as in Examples 1 to 3 were mixed well with a Henschel mixer (Model FM-75, manufactured by Mitsui Miike Kakoki Co., Ltd.), and then biaxially adjusted to a temperature of 150 ° C. Kneader (PCM
-30 type, manufactured by 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 obtained toner raw material was pulverized and classified by the apparatus system shown in FIG.
However, the conventional air-flow collision crusher shown in FIG. 9 was used as the crusher 28, and the one having the structure shown in FIG. 10 was used as the first classifier. The second classifying means 27 includes 3 similar to the first embodiment.
A split classifier was used.

In FIG. 10, the powder raw material introduced from the powder supply cylinder 280 together with the carrier air is introduced into a classification chamber 250 having a high graded classification plate 200 at the bottom. In the classifying chamber 250, the powder material is swirled and flown by the airflow that flows together, and is centrifuged into fine powder and coarse powder through the classification louver 290, and the fine powder is a fine powder discharge chute provided in the center of the classification plate 200. 2
The coarse powder is discharged from the coarse powder discharge port 210 provided on the outer peripheral portion of the classification plate 200.

The powdered raw material is supplied to the air flow classifier shown in FIG. 10 via the powder supply cylinder 280 by the injection feeder 35 at the rate of 13.0 kg / h by the first table-type fixed quantity supply device 21. And perform classification. The classified coarse powder is supplied through the coarse powder discharge hopper 230 from the supply port 165 of the object to be ground shown in FIG. 9 at a pressure of 6.0 kg / cm ² (G). , 6.0 Nm ³
/ Min pulverized with compressed air at a rate of
While being mixed with the pulverized raw material for toner production supplied at 7, the mixture was circulated again through the airflow classifier to perform closed-circuit pulverization. The classified fine powder is collected by the cyclone 23 while being entrained by the suction air from the suction fan.
It was introduced into the metering device 24. At this time, the fine powder had a weight average diameter of 7.1 μm, and contained 57% by number of particles having a particle diameter of 4.0 μm or less and a broad powder containing 8.0% by volume of particles having a particle diameter of 10.08 μm or more. It had a particle size distribution.

The obtained fine powder is passed through the second metering device 24 and further through the vibrating feeder 25 to the second classification means 2.
7 was introduced at a rate of 15.0 kg / h. As a result, a classified product having a weight average diameter of 6.9 μm, a particle size distribution including 27% by number of particles having a particle size of 4.0 μm or less and 1.5% by volume of particles having a particle size of 10.08 μm or more ( (Medium powder) was obtained with a classification yield of 81%. Thus, the classification / pulverization treatment efficiency was inferior to Example 1.

Comparative Example 2 Using the same toner raw materials as in Examples 1 to 3, pulverization and classification were performed in the same apparatus system. However, as the pulverizer 28, a conventional air-flow type collision pulverizer having the configuration shown in FIG.
The classifier having the structure shown in FIG. 10 was used, and pulverization was performed under the same apparatus conditions as in Comparative Example 1. The second classifying means 27 used was the same as that used in Example 1. The powder raw material is supplied to the first classification means 22 at a rate of 10.0 kg / h,
A fine powder having a weight average diameter of 6.3 μm was obtained. 12. Add this fine powder to
0 kg / h was introduced into the second classification means 27, and particles having a weight average diameter of 6.1 μm and a particle diameter of 4.0 μm or less
A classified product (medium powder) containing 3% by number and having a particle size distribution containing 0.5% by volume of particles having a particle size of 10.08 μm or more was obtained with a classification yield of 70%. Thus, Examples 2-3
The classification and pulverization treatment efficiency and the classification efficiency were inferior to those of the above.

Comparative Example 3 Materials having the same formulation as in Examples 4 and 5 were mixed well with a Henschel mixer (Model FM-75, manufactured by Mitsui Miike Kakoki Co., Ltd.), and then biaxially set at a temperature of 100 ° C. Kneader (PC
M-30, manufactured by Ikegai Iron Works Co., Ltd.). The obtained kneaded material was cooled and coarsely pulverized to 1 mm or less with a hammer mill to obtain a coarsely pulverized material as a powder raw material for producing a toner.
The obtained toner raw material was pulverized and classified by the apparatus system shown in FIG. However, the collision type airflow pulverizer having the configuration shown in FIG. 9 was used as the pulverizer, and the one having the configuration shown in FIG. 10 was used as the first classifier. The second classifying means 27 used was the same as that used in Example 1.

The pulverized raw material was supplied at a rate of 12.0 kg / h by the table type first fixed quantity feeder 21 to the airflow classifier shown in FIG. 10 through the powder supply tube 280 by the injection feeder 35. . The classified coarse powder is supplied through the coarse powder discharge hopper 230 from the pulverized material supply port 165 of the collision type air flow pulverizer shown in FIG.
After being crushed using compressed air of 0 kg / cm ² (G) and 6.0 Nm ³ / min, the mixture is circulated again to the first classification means 22 while being mixed with the powder raw material supplied at the raw material introduction section. Then, closed circuit pulverization was performed. On the other hand, the classified fine powder was collected by the cyclone 23 while being entrained by the suction air from the exhaust fan, and introduced into the second quantitative feeder 24.
At this time, the weight average diameter of the fine powder was 7.0 μm.

The obtained fine powder is passed through the second metering device 24 and further through the vibrating feeder 25 to the second classification means 2.
7 was introduced at a rate of 14.0 kg / h. As a result, a classified product having a weight average particle size of 6.5 μm, containing 28% by number of particles having a particle size of 4.0 μm or less, and having a particle size distribution containing 1.6% by volume of particles having a particle size of 10.08 μm or more ( (Medium powder) was obtained with a classification yield of 76%. Thus, the classification and pulverization processing efficiency was inferior to Examples 4 and 5.

The system of the embodiment and the comparative example and the classification
Grinding result

[0079]

As described above, according to the method for producing a toner of the present invention, a toner having a sharp particle size distribution can be obtained with a high classification / pulverization efficiency and a high classification yield, and the classification of toner production -The occurrence of problems such as fusing, coarsening, or agglomeration of toner in the pulverization process is effectively prevented, and abrasion of the device due to toner components is effectively prevented. As a result, continuous and stable production of high-quality toner is achieved. It can be performed. Further, according to the method for producing a toner of the present invention, a sharp image capable of obtaining an excellent image having a stable and high image density, excellent in durability, and free from image defects such as fog and poor cleaning, as compared with the conventional method. An excellent electrostatic image developing toner having a predetermined particle size can be obtained at low cost.
In particular, according to the present invention, it is possible to efficiently obtain a toner having a sharp particle size distribution with a weight average diameter of 10 μm or less, and further obtain a toner having a sharp particle size distribution with a weight average diameter of 7 μm or less. It is possible to obtain it efficiently.

[Brief description of the drawings]

FIG. 1 is an example of a flowchart showing an outline of a method for producing a toner of the present invention.

FIG. 2 is a schematic diagram showing an example of an apparatus system for performing the manufacturing method of the present invention.

FIG. 3 is a schematic sectional view of a preferred embodiment of a first classification means used in the production method of the present invention.

FIG. 4 is an enlarged view and an enlarged side view of the horizontal rotary rotor in FIG. 3;

FIG. 5 is a schematic sectional view of a preferred embodiment of a mechanical pulverizing means used in the production method of the present invention.

6 is a sectional view taken along line A-A 'in FIG.

FIG. 7 is an enlarged view of a stator surface in FIG. 5;

FIG. 8 is an enlarged view of a rotor surface in FIG. 5;

FIG. 9 is a schematic sectional view of a conventional collision-type airflow pulverizer.

FIG. 10 is an example of a pneumatic classifier used for a conventional first classifier.

FIG. 11 is an example of a flowchart showing an outline of a conventional toner manufacturing method.

FIG. 12 is a schematic sectional view of an example of a multi-segment classifier used for a second classifier.

[Explanation of symbols]

21: First quantitative feeder 22: First classifier 23: Collection cyclone 24: Second quantitative feeder 25: Vibration feeder 27: Second classifier 28: Crusher 29, 30, 31: Collection cyclone 33: Product 34: Fine powder 35: Injection feeder 41: Pulverized material supply pipe 42: Pulverized substance 43: Rotor 44: Stator 45: Machine base 46: Pulverized substance supply port 47: High pressure gas supply port 48: Top plate 49: lower surface plate 50: drive belt 51: upper casing 52: lower casing 53: pulverizing chamber 54: space 55: pulverized material discharge port 121: main body casing 122: classification chamber 123: guide chamber 124: classification rotor 125: raw material input port 126: air inlet 128: frequency converter 129: fine powder discharge pipe 130: fine powder collecting means 131: suction fan 132: coarse powder Outgoing hopper 133: Rotary valve 134: Blade 148, 149: Raw material supply pipe 158, 159, 160: Discharge port 161: High pressure gas supply nozzle 162: Acceleration pipe 163: Acceleration pipe outlet 164: Collision member 165: Crushed raw material supply port 166 : Collision surface 167: Pulverized material discharge port 168: Pulverization chamber 200: Classification plate 201: Classifier body casing 210: Coarse powder discharge port 220: Fine powder discharge chute 230: Coarse powder discharge hopper 240: Upper part of guide cylinder 250: Classification chamber 254 : Guide cylinder 260: Upper cover 270: Classification lower casing 280: Powder supply cylinder 290: Classification louver S: Gap L ₁ : Diameter of horizontal rotating rotor L ₂ : Length of horizontal rotating rotor blade θ: Horizontal rotating rotor Angle between the center and the straight line connecting the tip of the blade

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B07B 1/00-15/00 B02C 13/14

Claims (1)

(57) [Claims] 1. A mixture containing at least a binder resin and a colorant is melt-kneaded, and after cooling the obtained kneaded product,
The powdery raw material consisting of the coarsely pulverized product obtained by pulverizing the cooled product by the pulverizing means is first introduced into a first classification step using a rotary airflow classification means having a horizontal rotary rotor to produce fine powder and coarse powder. Then, the fine powder classified in the first classification step is introduced into the second classification step and further classified to obtain a classified product for producing a toner, and the coarse product classified in the first classification step is obtained. Production of toner in which powder is introduced as a material to be pulverized into a mechanical pulverizer and finely pulverized, and the finely pulverized material is mixed into the powder raw material and introduced into the first classifying step to perform circulation processing. A method, comprising: a rotor comprising at least a rotor attached to a central rotation axis; and a stator disposed around the rotor while maintaining a constant distance S from the rotor surface, and The annular space formed by holding S becomes airtight. Constructed by introducing a grinding object in the annular space of the mechanical grinding machine and a method for producing a toner, which comprises finely grinding the grinding object by high-speed rotation of the rotor as.