JP3138379B2 - Method for producing toner for developing electrostatic images - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to electrophotography, electrostatic recording,
The present invention relates to a method for producing a toner for developing an electrostatic image in electrostatic printing or the like.

[0002]

2. Description of the Related Art In image forming methods such as electrophotography, electrostatography and electrostatic printing, toner is used to develop an electrostatic image. In recent years, as the image quality and definition of copiers and printers have become higher and higher, the performance required for toner as a developer has become more severe, and the particle size of the toner has become smaller, and there is no coarse particle and fine powder. There has been a demand for a toner having a sharp particle size distribution with a small particle diameter.

[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. In the so-called one-component developing method disclosed in JP-A-54-42141 and JP-A-55-18656, various magnetic materials for imparting transportability and the like to the toner itself are used. And, if necessary, dry-mixing a releasing agent or a fluidity-imparting agent, followed by melt-kneading with a general-purpose kneading device such as a roll mill or an extruder, and after cooling and solidifying, a jet stream type pulverizer or machine. The powder is pulverized by various pulverizers such as an impact pulverizer and classified by various air classifiers to make the particle size necessary for the toner uniform. If necessary, a fluidizing agent, a lubricant and the like are dry-mixed to obtain a toner. Also, when used in a two-component development method, after mixing various magnetic carriers and toner,
Provide for image formation.

As described above, in order to obtain toner particles which are fine particles, the method shown in the flowchart of FIG. 13 is generally adopted. The crushed toner material, which is a crushed raw material, is continuously or sequentially supplied to the first classifying unit and classified, and the classified coarse powder mainly composed of a group of coarse particles having a specified particle size or more is sent to the crushing unit and crushed. After that, it is circulated again to the first classification means.

[0005] A finely pulverized toner mainly composed of particles having a particle diameter within the specified range and particles having a particle diameter equal to or smaller than the specified particle diameter is sent to a second classifying means, and a medium powder mainly composed of particles having a specified particle diameter is obtained. It is classified into a body and a fine powder mainly composed of a group of particles having a specified particle size or less. As the pulverizing means, various pulverizing devices are used.For pulverizing a coarsely pulverized toner mainly containing a binder resin,
As shown in FIG. 14, a jet air flow type pulverizer using a jet air flow, particularly a collision type air flow pulverizer, is used.

[0006] A collision type air flow pulverizer using a high-pressure gas such as a jet air stream conveys a pulverized raw material by a jet air stream, injects the pulverized raw material from an outlet of an acceleration tube, and opposes the pulverized raw material to an opening surface of an outlet of the acceleration tube. The pulverized raw material is pulverized by the impact force of the provided collision member. For example, FIG.
4, the high-pressure gas supply nozzle 2
A collision member 4 is provided opposite to the outlet 13 of the acceleration tube 3 to which the crushed raw material is supplied. The pulverized raw material 7 is sucked, and the pulverized raw material 7 is jetted out together with the high-pressure gas to collide with the collision surface 16 of the collision member 4 and to be pulverized by the impact.

Conventionally, as shown in FIGS. 14 and 15, a collision surface 16 of a collision member in such a pulverizer is perpendicular or inclined (for example, in the direction of the jet stream on which the pulverized raw material is loaded). 45 °) has been used (see JP-A-57-50554 and JP-A-58-143853). In the pulverizer shown in FIG. 14, a raw material 7 having a coarse particle diameter is supplied from a supply port 1 to an acceleration tube 3, and is crushed by a jet stream blown out from a jet nozzle 2.
6 and crushed by the impact force.
It is further discharged out of the crushing chamber 8. However, collision surface 1
6 is perpendicular to the axial direction of the acceleration tube 3, the jet nozzle 2
There is a high proportion of the raw material powder blown out from the surface and the powder reflected by the collision surface 16 coexisting near the collision surface 16, and therefore, the powder concentration near the collision surface 16 becomes high, so that the pulverization efficiency is reduced. Not good.

Further, the primary collision at the collision surface 16 is mainly performed, and it cannot be said that the secondary collision with the crushing chamber wall 6 is effectively used. Further, in a pulverizer in which the angle of the collision surface is perpendicular to the accelerating tube 3, fusion and agglomerates are liable to occur due to local heat generation at the time of the collision when the thermoplastic resin is pulverized, so that stable operation of the apparatus becomes difficult. This causes a reduction in the crushing ability.
Therefore, it was difficult to use the powder at a high powder concentration. In the pulverizer shown in FIG.
14, the powder concentration near the collision surface 16 is lower than that of the pulverizer of FIG. 14, but the pulverization pressure is dispersed and lower. Furthermore, it cannot be said that the secondary collision with the crushing chamber wall 6 is effectively used.

As shown in FIG. 15, when the angle of the collision surface 16 is inclined by 45 ° with respect to the accelerating tube 3, the above-mentioned problems are less when the thermoplastic resin is pulverized. However, the impact force used for crushing when colliding is small,
Further, since the pulverization due to the secondary collision with the pulverization chamber wall 6 is small, the pulverization ability is ２〜 to 1/1.
The grinding ability drops to 5. Japanese Unexamined Utility Model Publication No. 1-148740 and Japanese Unexamined Patent Application Publication No. 1-2254266 have been proposed as collision type air flow pulverizers in which the above problems are solved. In Japanese Unexamined Utility Model Publication No. 1-148740, as shown in FIG. 17, the raw material collision surface 16 of the collision member 4 is disposed at right angles to the axis of the acceleration tube 3, and the conical projection 14 is formed on the raw material collision surface. It has been proposed to provide such a structure to prevent the reflected flow at the collision surface.

[0010] Also, in Japanese Patent Application Laid-Open No. 1-254266,
As shown in FIG. 16, the tip portion of the collision surface 16 of the collision member 4 has a specific conical shape, so that the powder concentration near the collision surface is reduced so that the secondary collision with the crushing chamber wall 6 is efficiently performed. There has been proposed a collision type airflow pulverizer. Although the conventional problems can be considerably improved by the above-mentioned configuration, it is still not enough, and a finer pulverized product is desired as a recent need, and further, a fine pulverization with good pulverization efficiency is required. Machine is long-awaited.

For example, in the case of obtaining a toner having a weight average particle diameter of 8 μm and a volume percentage of particles of 4 μm or less of 1% or less, a collision type equipped with a classification mechanism for removing a coarse powder region. The raw material is pulverized to a predetermined average particle size by a pulverizing means such as an air current pulverizer and classified, and the pulverized material after removing coarse powder is subjected to another classifier to remove fine powder and remove desired medium powder. Have gained.

Incidentally, the weight average particle size mentioned here is data measured using a 100 μm aperture with a Coulter Counter TA-II type manufactured by Coulter Electronics (USA). It is also known that when the toner raw material is pulverized by the collision type air flow pulverizer using the jet air flow, the toner has a sharp angular projection on its surface when viewed microscopically.

These protrusions may hinder the fluidity of the toner. If the fluidity is poor, a bridge in a toner hopper such as a copying machine, a facsimile, a laser beam printer, etc., uneven charging of the toner surface, or Is a copier,
It is known that phenomena such as image density decrease occur when using a facsimile, laser beam printer, etc. for a long time, and it is known that one of the phenomena is due to poor toner fluidity. I have. As means for solving this problem, Japanese Patent Application Laid-Open No. 61-61627 and Japanese Patent Application Laid-Open
As disclosed in JP-A-249155, a method of pulverizing toner while pulverizing the toner is known.

However, these methods employ a method of crushing by collision between a rotor rotating at a high speed and a liner. However, in this method, the critical particle size of crushing is larger than that of a collision type air flow crusher using a jet air flow. When a finely ground particle size is desired for that purpose, the efficiency is significantly reduced. In particular, when attempting to obtain a toner fine powder having a weight average particle diameter of 9 μm or less, the efficiency is significantly reduced. Therefore, there is a demand for a method for producing a toner for developing an electrostatic image, which has good pulverization efficiency and excellent quality.

[0015]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a toner which overcomes the above-mentioned problems in the method for producing a toner. That is, an object of the present invention is to provide a method for producing a toner having good pulverization efficiency and a method for producing a toner having excellent fluidity.

The above object is achieved by the present invention described below. That is, the present invention provides a kneaded product by melt-kneading a mixture containing at least a binder resin and a coloring agent, cools the obtained kneaded product to obtain a cooled product, and crushes the obtained cooled product by crushing means. Pulverized to obtain a pulverized product, the obtained pulverized product is classified into coarse powder and fine powder by the first airflow classification means, and the classified coarse powder is finely pulverized by the collision type airflow pulverization means to produce fine powder. And
A toner for developing an electrostatic charge image, which classifies a powder having a prescribed particle size from the generated fine powder by a second airflow classifier and produces a toner for developing an electrostatic image from the classified powder having a prescribed particle size. In the manufacturing method, the impingement airflow crushing means is a pulverizer having an accelerating tube for conveying and accelerating the object to be crushed by a high-pressure gas, and a crushing chamber for crushing the object to be crushed, The object to be pulverized supplied and accelerated in the accelerating tube is discharged from the accelerating tube outlet into the pulverizing chamber, and is primarily pulverized by a projecting portion of a collision member having a collision surface provided opposite to the opening surface of the outlet of the accelerating tube. The primary pulverized material is secondarily pulverized on an outer peripheral collision surface provided on the outer periphery of the protruding portion, and the secondary pulverized secondary pulverized material is further subjected to tertiary pulverization on a side wall in the pulverizing chamber to be finely pulverized. After performing the process, it is circulated to the first airflow classification means, Apart in the classification by said milling step to fine powder by Rukoto given short time relatively low impact than the collision type air pulverizer means, angular fine powder has
A method for producing a toner for developing an electrostatic charge image, characterized in that the particle size is adjusted by a second airflow classifier after reducing the protrusions .

[0017]

In the method for producing a toner for developing an electrostatic charge image, a collision-type airflow pulverizing means includes an accelerating tube for conveying and accelerating the object to be ground by a high pressure gas, and a pulverizing chamber for finely pulverizing the object to be ground. As a fine pulverizer having the above, the object to be pulverized is supplied into the accelerating tube, the accelerated object to be pulverized is discharged into the pulverizing chamber from the outlet of the accelerating tube, and the collision surface provided opposite to the opening surface of the outlet of the accelerating tube. The primary pulverized material is primarily pulverized at the projecting portion of the collision member, and the primary pulverized primary pulverized material is secondarily pulverized at an outer peripheral collision surface provided on the outer periphery of the protruding portion, and the secondary pulverized secondary pulverized material is further pulverized After the tertiary pulverization is performed on the side wall in the room, the powder is circulated to the first airflow classification means, and the fine powder classified by the first airflow classification means is formed into fine powder.
Apart from this pulverizing step, a relatively low impact is applied for a short time from the impinging airflow pulverizing means, and then the particle size is adjusted by the second classifying means to provide a toner excellent in pulverizing efficiency and fluidity. I can do it.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described more specifically with reference to the accompanying drawings showing preferred embodiments. FIG. 1 is an example of a flowchart showing an outline of the manufacturing method of the present invention. In the present invention, the pulverized raw material is supplied to the first classification means, and is classified into coarse powder and fine powder in the first classification means. The coarse powder is introduced and pulverized into the impingement type air flow pulverization means,
After pulverization, it is circulated and introduced into the first classification means. The fine powder is
After being treated by the low impact means, it is classified by the second classifying means and classified into at least a medium powder having a particle size within a specified particle size and a fine powder having a particle size not more than a specified particle size.
The classified medium powder is used as a toner as it is, or used as a toner after being mixed with an additive such as hydrophobic colloidal silica. The classified fine powder is desirably supplied to a melt-kneading step for producing a pulverized raw material and reused.

As an example of the impingement type air current pulverizer used in the present invention, an impingement type air current pulverizer of the type shown in FIG. 2 is exemplified. In FIG. 2, the raw material 7 to be ground is
The material is supplied to the accelerating tube 3 from a pulverized raw material supply port 1 provided on the pulverizer wall 11 above the accelerating tube 3. A compressed gas such as compressed air is introduced into the acceleration tube 3 from the compressed gas supply nozzle 2, and the pulverized raw material 7 supplied to the acceleration tube 3 is instantaneously accelerated to have a high speed. Acceleration tube outlet 1 at high speed
The pulverized raw material 7 discharged into the pulverizing chamber 8 from the
Is crushed by colliding with the colliding surface.

In the crusher shown in FIG. 2, a protruding central portion 14 having a conical shape is formed on a collision surface of a collision member, and a primary pulverized material to be pulverized around the protruding central portion at the protruding central portion. It further has an outer peripheral collision surface 15 for crushing the object by collision. Further, the pulverizing chamber 8 has a side wall 6 for tertiary pulverizing the secondary pulverized material pulverized by the outer peripheral collision surface 15 by collision.
have.

FIG. 3 is a cross-sectional plan view of FIG. 2 and will be described in more detail. By providing the conical projection 14 having a central portion protruding on the raw material collision surface as described above, the solid-gas mixed flow of the pulverized raw material and the compressed air ejected from the accelerating tube 3 is reduced to the projection 1
4 is firstly pulverized on the surface 4 and then secondarily pulverized on the outer peripheral collision surface 15, and then thirdly pulverized on the pulverization chamber side wall 6. At this time,
The vertex angle α (°) of the projecting central portion 14 protruding from the collision surface of the collision member 4 and the inclination angle β (°) of the outer peripheral collision surface 15 with respect to the plane perpendicular to the central axis of the accelerating tube are 0 <α <90, β When the inequality> 0 30 ≦ α + 2β ≦ 90 is satisfied, grinding is performed very efficiently.

When α ≧ 90, the reflected flow of the primary pulverized material on the surface of the projection central portion 14 disturbs the flow of the solid-gas mixed flow ejected from the acceleration tube 3, which is not preferable. β =
When the value is 0, that is, when the outer peripheral collision surface is perpendicular to the solid-gas mixed flow as shown in FIG. 17, the reflected flow at the outer peripheral collision surface 15 flows toward the solid-gas mixed flow. Undesirably, turbulence of the gas mixture flow occurs. When β = 0, the powder concentration on the outer peripheral collision surface 15 increases, and when a powder of a thermoplastic resin or a powder mainly composed of a thermoplastic resin is used as a raw material, Fused products and aggregates are easily formed.
When such a fusion occurs, stable operation of the apparatus becomes difficult.

On the other hand, when α and β satisfy α + 2β <30, the impact force of the primary pulverization on the surface of the projections is weakened, so that the pulverization efficiency is undesirably reduced. Α and β are α
When + 2β> 90, the reflected flow at the outer peripheral collision surface flows downstream of the solid-gas mixed flow, so that the impact force of the tertiary pulverization on the side wall of the pulverization chamber is weakened and the pulverization efficiency is reduced. As described above, when α and β satisfy 0 <α <90, β> 0 30 ≦ α + 2β ≦ 90, and more preferably, 10 <α <805 and 5 <β <40, as shown in FIG. The secondary and tertiary pulverization are performed efficiently, and the pulverization efficiency can be improved.

It is a feature of the present invention to increase the number of collisions and make the collision more effective as compared with the conventional pulverizer.
It is possible to improve the pulverization efficiency, to prevent the generation of fused material at the time of pulverization, and to perform a stable operation. The configuration of the crusher used in the present invention is not limited to the configuration shown in FIG. FIG. 4 is a schematic sectional view of another preferred pulverizer used in the present invention, FIG. 5 is an enlarged sectional view taken along line AA ′ of FIG. 4, and FIG.
It is sectional drawing in the B 'line.

The pulverizer shown in FIG. 4 will be described. An accelerating tube 21 for conveying and accelerating an object to be pulverized by high-pressure gas, and a collision member 3 having a collision surface provided opposite to the outlet of the accelerating tube.
0, the acceleration pipe 21 has a Laval nozzle shape, and a high-pressure gas ejection nozzle 23 is disposed upstream of a throat portion of the acceleration pipe 21. The outer wall of the high-pressure gas ejection nozzle 23 and the throat portion 2
An object supply port 24 is provided between the inner walls of the
The grinding chamber provided in connection with the outlet of No. 1 has a circular cross section in the axial direction.

The crushed material supplied from the crushed material supply cylinder 25 is formed such that the inner wall and the center of the acceleration tube throat portion 22 of the acceleration tube 21 having a Laval nozzle shape whose central axis is disposed in the vertical direction are the center of the acceleration tube 21. The material reaches a pulverized material supply port 24 formed between the shaft and the outer wall of the high-pressure gas ejection nozzle 23. On the other hand, the high-pressure gas is introduced from the high-pressure gas supply port 26, passes through the high-pressure gas chamber 27, passes through one or preferably a plurality of high-pressure gas introduction pipes 28, and sharply moves from the high-pressure gas ejection nozzle 23 toward the acceleration pipe outlet 29. Spouting while expanding.

At this time, due to the ejector effect generated in the vicinity of the accelerating tube throat portion 22, the material to be ground is directed from the material supply port 24 toward the outlet 29 of the accelerating tube while being entrained by the gas coexisting therewith. And accelerates rapidly while being uniformly mixed with the high-pressure airflow in the accelerating tube throat portion 22. The solid-mixed airflow is uniformly distributed on the collision surface of the collision member 30 disposed opposite to the acceleration tube outlet 29 without unevenness of the dust concentration. Clash in state. Since the impact force generated at the time of collision is given to the sufficiently dispersed individual particles (objects to be crushed), very efficient crushing can be performed. The pulverized material pulverized on the collision surface of the collision member 30 repeats collision between the pulverizing chamber side wall 32 and the surface of the collision member 30 to further improve the pulverization efficiency, and is disposed behind the collision member 30. It is discharged from the pulverized material discharge port 33.

The collision surface of the collision member 30 has a protruding central portion 14 and an outer periphery around the protruding central portion for further crushing the primary pulverized material pulverized at the protruding central portion by collision. It has a collision surface 15. Further, the pulverizing chamber 34 has a side wall 32 for tertiary pulverization of the secondary pulverized material secondary pulverized on the outer peripheral collision surface by collision. As in the pulverizer of FIG. 2, the object to be pulverized is primarily pulverized on the surface of the protrusion on the collision surface, further pulverized at the outer collision surface 15, and then tertiarily pulverized at the side wall 32 of the pulverizing chamber.

In the pulverizer shown in FIG. 4, the center axis of the accelerating tube is disposed vertically, and the material to be pulverized is supplied from the inner wall of the accelerating tube and the outer wall tube of the high-pressure gas jet nozzle. By supplying the same direction of supply, the material to be ground can be dispersed in a high-pressure air stream that is uniformly jetted without deviation due to the dust concentration. Examples of other pulverizers used in the present invention are shown in FIGS. FIG. 8 is a cross-sectional view taken along line CC ′ of FIG.

The pulverizer shown in FIG. 7 will be described. The pulverizer is provided with an accelerating tube 21 for conveying and accelerating the pulverized raw material by a high-pressure gas, and a collision surface for pulverizing the powder ejected from the accelerating tube 21 by a collision force. A thrust portion 36 of a Laval-shaped accelerating tube 21 and an accelerating tube outlet 37, wherein the impingement member 30 is provided to face the outlet of the accelerating tube. And a grinding material supply port 24 in the entire circumferential direction of the accelerating tube is provided, and the grinding chamber has a substantially circular cross section, and the collision member 3
This is a collision type airflow pulverizer provided with a pulverized material discharge port 33 at the rear.

The central axis of the accelerating tube 21 has a vertical direction, and the collision surface of the collision member 30 has a protruding central portion 14 and pulverized around the protruding central portion at the protruding central portion. It has an outer peripheral collision surface 15 for further crushing the primary crushed material by collision. The pulverizing chamber 34 has a side wall 32 for tertiary pulverizing the secondary pulverized material secondary pulverized on the outer peripheral collision surface by collision. The operation of the high-pressure gas will be described. First, the high-pressure gas enters from the high-pressure gas supply ports 27 on the left and right sides of the high-pressure gas chamber 27, and after the arteries are made uniform, such as pressure fluctuations, the central portion of the supply tube 25 for the material to be pulverized. From the Laval nozzle 35 provided to the acceleration tube 21.

Like the Laval nozzle 35, the accelerating tube 21 also has a flared Laval shape, and the high-pressure gas flowing into the accelerating tube 21 is accelerated to a supersonic region while expanding.
In the process, the high-pressure gas is depressurized, and the pressure of the gas at the time of exiting the acceleration tube 21 becomes substantially the same as the pressure of the pulverizing chamber 34. On the other hand, in the circular crushing chamber 34, the crushing chamber 34
When the gas inside is sucked, a suction flow is generated inside the grinding chamber. Then, the surface of the collision member 30 is reduced in pressure by the action of the suction flow. The shape of the crushing chamber is not limited to this.

By the depressurizing action on the surface of the collision member 30, the jet flow from the acceleration tube 21 is further accelerated and collides with the surface of the collision member 30. At this time, the object to be pulverized is primarily pulverized on the surface of the protrusion 14 on the collision surface of the collision member 30, further pulverized at the outer collision surface 15, and then tertiarily pulverized at the pulverization chamber side wall 32. Next, the operation of the supplied raw material will be described. The raw material to be pulverized is supplied from a pulverized material supply cylinder 25. The supplied pulverized raw material is sucked and discharged to the accelerating tube 21 from the pulverized raw material supply port 24 provided at the lower part of the supply cylinder. The principle of the suction and discharge of the raw material is based on the ejector effect by the expansion and decompression of the high-pressure gas in the accelerating tube described above. At this time, since the pulverized raw material supply port 24 is provided in the entire circumferential direction of the accelerating tube between the throat portion of the accelerating tube having the Laval shape and the accelerating tube outlet, it is sufficiently dispersed and accelerated by the high-speed airflow.

It should be noted that the pulverized raw material supply port 24 is preferably provided in the entire circumferential direction or in a plurality (n ≧ 2). If there is only one supply port for the pulverized raw material, the dispersion state of the raw material in the accelerating tube becomes uneven, which causes a decrease in the pulverization efficiency, which is not preferable. The pulverized raw material dispersed and sucked in the accelerating tube 21 in this manner is completely dispersed by the high-speed airflow radiated from the Laval nozzle 35 provided at the center of the pulverized material supply cylinder 25.

Next, the dispersed pulverized raw material is
It is accelerated by the high-speed airflow flowing inside and becomes a supersonic solid-gas mixed flow. The solid-gas mixed flow becomes a solid-gas mixed jet after exiting the accelerating tube 21 and collides with the collision member 30 under the same action as the above-mentioned jet. In the pulverizer shown in FIG. 7, the center axis of the acceleration tube is disposed in the vertical direction, and a specific raw material supply method is used, and the raw material powder to be pulverized is more strongly dispersed to improve the pulverization efficiency. And excellent pulverizing capacity can be obtained. In addition, due to the uniform dispersion of the dust concentration due to the strong dispersion of the material to be crushed, the local fusion and wear of the material to be crushed in the colliding member, the acceleration tube and the crushing chamber are greatly increased as compared with the conventional collision type air-flow crusher. It can be reduced and can be operated stably.

The pulverizers shown in FIGS. 4 and 7 are different from the pulverizers shown in FIG.
Since the pulverized raw material in the acceleration tube can be more uniformly dispersed, the pulverization efficiency can be further improved. still,
4 and 7, also when α and β satisfy 0 <α <90, β> 030 ≦ α + 2β ≦ 90, and more preferably 10 <α <805 and 5 <β <40, The secondary and tertiary pulverization are performed efficiently, and the pulverization efficiency can be improved.

In the above-mentioned pulverizer, it is preferable that the inside diameter of the outlet of the acceleration tube is smaller than the inside diameter b of the collision member. It is preferable that the center of the accelerating tube and the tip of the protruding central portion that protrudes from the collision surface of the collision member substantially coincide with each other in terms of uniform pulverization. The distance a between the outlet of the acceleration tube and the end of the collision surface of the collision member is preferably 0.1 to 2.5 times or less, more preferably 0.2 to 1.0 times the diameter of the collision member. If it is less than 0.1 times, the dust concentration in the vicinity of the collision surface increases, while if it exceeds 2.5 times, the impact force is weakened, and the crushing efficiency tends to decrease.

Further, the shortest distance c between the end of the collision surface of the collision member and the side wall (inner wall) of the crushing chamber is equal to 0.1 mm of the diameter b of the collision member.
It is preferably 1 to 2 times or less. If the pressure is less than 0.1 times, the pressure loss at the time of passage of the high-pressure gas is large, and not only the pulverization efficiency is reduced, but also the flow of the pulverized material tends not to be smooth. The effect of the tertiary collision of the object to be crushed is reduced, and the crushing efficiency is reduced. The shape of the crushing chamber is not particularly limited as long as the distance between the end of the collision surface of the collision member and the side wall of the crushing chamber satisfies the above value.

More specifically, the length of the accelerating tube is 50 to 5
00 mm is preferable, and the diameter of the collision member is 30 to 300 m.
It is preferable to have m. Further, it is preferable in terms of durability that the collision surface of the collision member and the side wall of the pulverizing chamber are made of ceramic. By crushing with such an impinging airflow crushing means, the crushing ability and crushing efficiency of the crusher are significantly improved. In particular, this effect becomes more remarkable as the desired particle size is smaller. It is particularly effective when producing toner fine powder having a weight average particle diameter of 9 μm or less.

As the first classifying means used in the present invention, a known air classifier is used. For example, DS classifier manufactured by Nippon Pneumatic Industries Co., Ltd., Micron Separator manufactured by Hosokawa Micron Co., Ltd., Turbo Classifier manufactured by Nisshin Engineering Co., Ltd., Dona Selec manufactured by Donaldson Japan Co., Ltd. and the like can be mentioned. Examples of the low impact means include a method in which an impact is applied between a rotating rotor, a blade or a hammer and a liner opposed thereto, or an impact is applied between a number of rotating pins.

FIG. 9 is a schematic sectional view of a low-impact processing apparatus using a combination of a rotor and a liner. In the figure, 43 is a rotating shaft, 44 is a casing, 45 is a liner, 46 is a blower blade, 47 is a rotor (with a blade), 48 is an outlet, 49 is a product outlet, 38 is a return path, 39 is a raw material supply port, 40 Is an inlet, 41 is a jacket, and 42 is a return closing valve. The peripheral speed at the tip of the rotating rotor is 5
0 to 200 m / sec, preferably 70 to 150 m / s
ec, and the processing temperature is the glass transition point of the processing raw material−
The treatment is preferably performed in a temperature range from 5 ° C. to a glass transition point of −30 ° C. If the processing temperature is too high, the material to be crushed is melted in the apparatus, and if the processing temperature is too low, the crushing processing becomes insufficient, which is not preferable. In order to control the temperature in such a range, cooling or heating is performed as a jacket structure. Alternatively, the temperature may be controlled by introducing cold air or hot air together with the processing raw materials to be charged.

FIG. 10 is a view showing the positional relationship between the liner 45 and the rotating rotor 47 of the low impact processing apparatus shown in FIG. The distance between the liner 45 and the rotor 47 refers to the difference between the circumference obtained by connecting the tips of the protrusions to the inner circumference of the liner and the radius of the two circumferences of the locus of the protrusions of the rotor.
The same applies to blades and hammers instead of this rotor.

The distance between the rotor, the blade or the hammer and the liner is about 0.5 to 10 mm, preferably 0.1 to 10 mm.
Good results have been obtained with a thickness of about 5 to 3 mm. FIG.
1 is a schematic sectional view of another type of low impact processing apparatus.
The device comprises a cylindrical casing 51 and this casing 5.
1 and a rotor 52 disposed coaxially with the casing shaft. The rotor 52 is provided with a plurality of blades 53. Liner 54 and rotor blade 53
There is a space of an appropriate size (a gap of 0.5 to 10 mm, preferably 0.5 to 3 mm) between them to form the processing region 55. On the upstream side of the casing 51, a supply port 58 for the toner processing product 56 and the inflow air 57 is provided. A spiral chamber 59 is provided below the supply port 58. Distributors 60 for uniformly distributing the input material 56 and / or the inflow air 57 into the processing area 55 are provided on the rotor blade 53 near the spiral chamber 59.
Are provided as appropriate.

A discharge port 61 is provided on the downstream side of the casing 51, and is connected to, for example, a cyclone collector or a bag filter outside the system. In the apparatus shown in FIG. 11, the peripheral speed and the processing temperature of the rotor blade 53 rotating at a high speed are preferably set in the same ranges as those in the apparatus shown in FIG.
In the low-impact treatment in the apparatus shown in FIGS. 9 and 11, the treatment may be carried out temporarily, or may be carried out by recycling in which the residence time can be controlled. This may be appropriately set depending on the physical properties of the processing raw material and the degree of processing, but in consideration of productivity, it is preferable to set conditions so that the processing can be performed as transiently as possible. As such an apparatus, “Kryptron” manufactured by Kawasaki Heavy Industries, Ltd., “Turbo Mill” manufactured by Turbo Kogyo, or the like may be used.

Since the purpose of the low impact treatment in the present invention is not to make the toner particles spherical but to modify the surface characteristics, the residence time in the apparatus is extremely short, and the time is determined by the properties of the respective toner processing raw materials and the rotor. Depends on the peripheral speed of
For example, the peripheral speed is 200 m / sec for 0.01 second to 2 seconds, and is selected from about 0.01 to 3 minutes depending on conditions. Therefore, there is little influence on the shape and the surface of the toner, and the ratio of the minor axis to the major axis of the toner at the time of pulverization changes from 0.60 to 0.70 to about 0.65 to 0.85 after processing. is there. When the state of the toner surface after the treatment is observed with a scanning electron microscope, a large change in the shape is not seen as compared with before the treatment, but it is recognized that the angular projections are reduced.

If the low impact treatment time (residence time) is set to be longer than the above-mentioned time, spheroidization of the toner is promoted,
Phenomena such as an increase in toner consumption and an increase in fogging due to a decrease in cleaning performance become strong. Conversely, if it is too short, the effect of modifying the surface properties is weakened, and there is a tendency that the fluidity of the toner is deteriorated. . As the second classifying means used in the present invention, the above-mentioned known air classifier is used. Particularly preferably used, for example, a multi-segment classifier shown in FIG. 12 (cross-sectional view) can be exemplified as one of the specific examples.

In FIG. 12, the side walls are 122 and 124.
The lower wall has a shape indicated by 125, and the lower wall 123 and the lower wall 125 are provided with knife-edge classifying edges 117 and 118, respectively. The classification zone is divided into three. A raw material supply nozzle 116 that opens to the classification chamber is provided below the side wall 122, and a Coanda block 126 that is bent downward in the direction of extension of the tangent at the bottom of the nozzle and that draws a long elliptical arc is provided. Classification room upper wall 127
Is a knife edge type inlet edge 11 toward the lower part of the classification chamber.
9 and air inlet pipes 114 and 115 that open to the classification chamber are provided above the classification chamber. Inlet tubes 114 and 1
15, a first gas introduction adjusting means 120 such as a damper;
Second gas introduction adjusting means 121 and static pressure gauges 128 and 12
9 are provided. The positions of the classification edges 117 and 118 and the inlet edge 119 differ depending on the type of the fine powder and the desired particle size. The outlets 111, 112, and 1 that open into the chamber are provided on the bottom of the classification chamber so as to correspond to the respective fractionation areas.
13 are provided. The outlets 111, 112 and 113 may be provided with opening and closing means such as valve means, respectively.

The fine powder supply nozzle 116 is composed of a right-angled cylinder and a pyramid-shaped cylinder. When the ratio of the inner diameter of the right-angled cylinder to the inner diameter of the narrowest part of the pyramid-shaped cylinder is set to 20: 1 to 1: 1, Good introduction speed is obtained. The classification operation in the multi-division classification region configured as described above is performed, for example, as follows.
The pressure in the classification area is reduced through at least one of the outlets 111, 112 and 113, and the airflow flowing by the reduced pressure in the raw material supply nozzle 116 opened in the classification area is
Fine powder is supplied to the classification area through the fine powder supply nozzle 116 at a flow rate of 50 to 300 m / sec.

When the fine powder is supplied to the classification region at a flow rate of less than 50 m / sec, it is difficult to sufficiently disintegrate the fine powder, and the classification yield and the classification accuracy are likely to be lowered.
When the fine powder is supplied to the classification region at a flow rate of more than 300 m / sec, the particles tend to be crushed due to collision of the particles, and the fine particles are easily generated, which tends to cause a decrease in the classification yield.

The supplied fine powder moves along a curved line 130 by the action of the Coanda block 126 due to the Coanda effect and the action of gas such as air flowing in at that time.
Classification is performed according to the size of each particle size and the size of the weight.
Assuming that the specific gravity of the particles is the same, the large particles (coarse powder) are outside the airflow (that is, the first particles on the left side of the classification edge 118).
The intermediate powder (particles having a particle diameter within the specified range) is classified into a second fractionation area between the classification edges 118 and 117, and the fine powder (particles having a particle diameter smaller than the specified particle size) is classified. Edge 117
Is classified into the third fractionation area on the right side of The classified coarse powder is discharged from a discharge port 111, the medium powder is discharged from a discharge port 112, and the fine powder is discharged from a discharge port 113.

For the introduction of fine powder into the classification area, a method of sucking and introducing utilizing the suction force of a cyclone; air supply means such as injection is provided in the fine powder supply nozzle;
There is a method of introducing by a suction force from a cyclone and a force of compressed air from an injection; The introduction method using air conveyance means such as suction introduction or injection has better sealing performance of the device system,
It is preferable since it is not required than the pressure type introduction.

The multi-segmentation classifier, which is the second classifier, includes:
Classification means having a Coanda block such as an elbow jet manufactured by Nippon Steel Mining Co., Ltd. and utilizing the Coanda effect can be given. The size of the classification area of the multi-segment classifier is usually [1
0 to 50 cm] × [10 to 50 cm], the fine powder can be classified into three or more particle groups in an instant of 0.1 to 0.01 seconds or less. When the multi-segmentation classifier is fractionated into three, the fines are divided into a coarse powder (particles having a specified particle size or more), a medium powder (particles having a specified particle size) and a fine powder ( (Particles having a specified particle size or less).

Thereafter, the coarse powder passes through a discharge conduit 111 and is collected via a collecting cyclone (not shown).
It is preferable that the collected coarse powder is returned to the pulverizing step and subjected to pulverization again from the viewpoint of improving production efficiency. Medium powder is discharge conduit 1
The toner is then discharged out of the system through the collector 12, collected by a collecting cyclone, and collected as a toner product. The fine powder is discharged out of the system via the discharge conduit 113, collected by the collecting cyclone, and then collected as fine powder having a particle diameter outside the specified range. The collection cyclone also functions as suction decompression means for sucking and introducing fine powder into the classification area via the nozzle 116. The recovered fine powder is desirably supplied to a melt-kneading step for producing a pulverized raw material and reused.

In the present invention, the pulverizing step shown in the flow chart of FIG. 1 is not limited to this. For example, two pulverizing means and one pulverizing means or one pulverizing means and one first pulverizing means may be used. There may be more than one means each. What kind of combination constitutes the pulverizing step may be appropriately set depending on a desired particle size, a constituent material of toner particles, and the like. In this case, where the coarse powder to be returned to the pulverizing step is to be returned may be appropriately set. The multi-segmentation classifier as the second classifying means is not limited to the shape shown in FIG. 12, but has an optimum shape according to the particle size of the pulverized raw material, the desired medium powder particle size, the true specific gravity of the powder, and the like. What should be adopted.

The method for producing a toner of the present invention can be preferably used for producing toner particles used for developing an electrostatic image. To prepare a toner for developing an electrostatic image, a colorant or a magnetic powder, a vinyl-based or non-vinyl-based thermoplastic resin, a charge control agent, and other additives as necessary are mixed using a Henschel mixer or a ball mill. After thoroughly mixing with a machine, a heating roll, a kneader, a hot kneader such as an extruder is melted, kneaded and kneaded to disperse or dissolve the pigment or dye while the resins are mutually compatible, After cooling and solidifying, pulverization and classification are performed to obtain a toner. The production method of the present invention is used in such a pulverization step and a classification step.

Next, 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, a homopolymer of styrene such as polystyrene, poly-p-chlorostyrene, polyvinyltoluene and a substituted product thereof; styrene-p-chlorostyrene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene Copolymer, styrene-acrylate copolymer, styrene-methacrylate copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-
Styrene such as vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer -Based copolymers: polyvinyl chloride, phenolic resin, natural resin modified phenolic resin, natural resin modified maleic acid resin, acrylic resin, methacrylic resin, polyvinyl acetate, silicone resin, polyester resin, polyurethane, polyamide resin, furan resin,
Epoxy resin, xylene resin, polyvinyl butyral,
Terpene resins, coumarone indene resins, petroleum resins and the like can be used.

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, and An important issue is the adhesion of the toner to the toner image supporting member. Toners that fix with less heat energy tend to block or cake during storage or in a developing unit, and these problems must also 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 the study of the present inventors, when the content of the magnetic substance 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 the toner is hardly applied with oil, the selection of the binder resin is more important. Preferred binders include cross-linked styrenic copolymers or cross-linked polyesters.

Examples of the comonomer for the styrene monomer of the styrene copolymer include acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, and the like.
Duplex such as dodecyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide, etc. A monocarboxylic acid having a bond or a substituted product thereof; for example, a dicarboxylic acid having a double bond such as maleic acid, butyl maleate, methyl maleate, dimethyl maleate and the like; and a substituted product thereof; for example, vinyl chloride, vinyl acetate Vinyl esters such as vinyl benzoate; ethylene olefins such as ethylene, propylene and butylene; vinyl ketones such as vinyl methyl ketone and vinyl hexyl ketone; vinyl methyl ether; Alkenyl ether, such vinyl ethers and vinyl isobutyl ether; vinyl monomers are used singly or two or more.

As the crosslinking agent, a compound having two or more polymerizable double bonds is mainly used, for example, an aromatic divinyl compound such as divinylbenzene, divinylnaphthalene, etc .; for example, ethylene glycol diacrylate, Ethylene glycol dimethacrylate,
Carboxylic acid esters having two double bonds such as 1,3-butanediol dimethacrylate; divinyl compounds such as divinylaniline, divinyl ether, divinyl sulfide and divinyl sulfone; and compounds having three or more vinyl groups; Are used alone or as a mixture.

When a pressure fixing method or a light heat pressure fixing method is used, a binder resin for a pressure fixing toner can be used, for example, polyethylene, polypropylene, or the like.
Polymethylene, polyurethane elastomer, ethylene-
Examples thereof include an ethyl aryurilate 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 blended (internally added) to the toner particles before use. The charge control agent makes it possible to control the optimal charge amount according to the development system, and in particular, it is possible to further stabilize the balance between the particle size distribution and the charge. It is possible to further clarify the function separation and the complementarity for higher image quality in each particle size range.

As the positive charge controlling agent, a modified product of nigrosine and a fatty acid metal salt: a quaternary ammonium salt such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate and tetrabutylammonium tetrafluoroborate; Alternatively, two or more kinds can be used in combination. Among these, a charge control agent such as a nigrosine compound or a quaternary ammonium salt is particularly preferably used. Also, the following general formula

Embedded image (R ₁ in the above formula is H or CH ₃ , and R ₂ or R ₃
Is a substituted or unsubstituted alkyl group (preferably C ₁ -C
₄ )) A monomer homopolymer or a copolymer with a polymerizable monomer such as styrene, acrylate or methacrylate as described above can be used as a positive charge control agent. In addition, these charge control agents also function as (all or part of) a binder resin.

As the negative charge control agent, for example, an organometallic complex or a chelate compound is effective. 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 or salt, particularly preferably a salicylic acid-based metal complex or 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 preferably 4 μm or less (more preferably 3 μm or less).

At the time of internal addition to the toner, such a charge controlling 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, the magnetic material contained in the magnetic toner includes iron oxides such as magnetite, γ-iron oxide, ferrite, and iron-rich ferrite; metals such as iron, cobalt, and nickel; Alloys of metals such as aluminum, cobalt, copper, lead, magnesium, tin, zinc, antimony, beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, vanadium, and mixtures thereof. .

These ferromagnetic materials have an average particle size of 0.1 to 1
μm, and preferably about 0.1 to 0.5 μm.
The amount is from 60 to 110 parts by weight, preferably from 65 to 100 parts by weight, per 100 parts by weight of the resin component.

As the colorant used in the toner, conventionally known dyes and / or pigments can be used. For example, carbon black, phthalocyanine blue, peacock blue, permanent red, lake red, rhodamine lake, Hanza yellow, permanent yellow, benzidine yellow and the like can be used. The content is 0.1 to 20 parts by weight, preferably 0.5 to 20 parts by weight with respect to 100 parts by weight of the binder resin. In order to further improve the transparency of the OHP film on which the toner image is fixed, It is preferably at most 12 parts by weight, more preferably from 0.5 to 9 parts by weight.

[0068]

Next, the present invention will be described more specifically with reference to examples and comparative examples. Example 1 100 parts by weight of styrene-butyl acrylate-divinylbenzene copolymer (monomer weight ratio 80.0 / 19.0 / 1.0, weight average molecular weight Mw 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,
After mixing well with 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 0 ° C. The obtained kneaded product was cooled and coarsely pulverized to 1 mm or less with a hammer mill to obtain a coarse powder for toner production. The obtained toner pulverized raw material was subjected to pulverization, low impact treatment, and classification by the production method shown in FIG.

The impingement type air flow pulverizer uses an apparatus having the structure shown in FIG. 2 and has a conical projection having a vertex angle of 50 ° (α = 50 °). The inclination angle of the central axis with respect to the vertical plane was 10 ° (β = 10 °) (α
+ 2β = 70 °). The diameter of the collision member is 90 mm (b
= 90 mm), the distance between the end of the collision surface and the outlet of the accelerating tube is 50 mm (a = 50 mm), the shortest distance to the wall of the grinding chamber is 20 mm (c = 20 mm), and the shape of the grinding chamber is box-shaped. went. The first classifier used was a forced vortex type airflow classifier.

In a table type quantitative feeder, the pulverized raw material is supplied to an airflow classifier at an injection feeder at a rate of 31.0 kg / h, and the classified coarse powder is supplied to the pulverized raw material of the collision type airflow pulverizer. Supplied from port 1 and pressure 6.0
After being pulverized using compressed air of Kg / cm ² (G) and 6.0 Nm ³ / min, while being mixed with the toner pulverized raw material supplied in the raw material introduction section, the mixture is circulated again to the airflow classifier. And closed-circuit pulverization to obtain classified fine powder.
At this time, the weight average diameter of the fine powder was 8.8 μm,
It had a sharp particle size distribution substantially not containing 6.0 μm or more.

The particle size distribution of the toner can be measured by various methods. In the present embodiment, the measurement was performed using a Coulter counter. Coulter counter TA as measuring device
An interface (manufactured by Nikkaki) and a CX that output the number distribution and volume distribution using a type II (manufactured by Coulter)
-1 Persol computer (manufactured by Canon Inc.) is connected, and a 1 wt% aqueous solution of NaCl is prepared using primary sodium chloride as an electrolyte. As a measuring method, the electrolytic solution 100
0.1 to 5 ml of a surfactant, preferably an alkylbenzenesulfonate, is added as a dispersant in ~ 150 ml;
Further, 2 to 20 mg of a measurement sample is added. The electrolytic solution in which the sample was suspended was subjected to a dispersion treatment for about 1 to 3 minutes with an ultrasonic disperser, and the Coulter Counter TA-II was used, and a 100 μm aperture was used as an aperture. The particle size distribution was measured, and values such as the weight average particle size and the number average particle size were determined therefrom.

The obtained fine powder was controlled in a low-impact processing apparatus shown in FIG. 9 so that the rotation speed of the rotor was 130 m / sec, the clearance between the liner and the rotor was 2 mm, and the outlet temperature of the apparatus was controlled at 40 ° C. The treatment was performed under the following conditions. The processed toner is transferred to a scanning electron microscope (Hitachi, Ltd. S
(-800 type), no major change was observed in the shape as compared to before the treatment, but it was confirmed that the angular portion was reduced. Incidentally, the weight average diameter after the treatment was 8.
It was 7 μm.

The treated fine powder was classified by the multi-segment classifier shown in FIG. At the time of introduction into the multi-segmentation classifier, the suction force generated from the pressure reduction in the system due to the suction pressure reduction of the collection cyclone communicating with the discharge ports 111, 112 and 113 and the compression from the injection attached to the raw material supply nozzle 116 Utilized air. The introduced fine powder was classified instantaneously in 0.01 seconds or less. The classified coarse powder was collected by a collection cyclone, and then introduced again into the pulverizer. The classified medium powder has a weight average particle size of 8.1 μm.
(Contains 0.9 volume% of particles having a particle size of 4.0 μm or less and 0.5 volume% of particles having a particle size of 12.7 μm or more) and is excellent for toner use. Had performance.

The classified fine powder was returned to the kneading step and reused. At this time, the ratio of the finally obtained medium powder to the total amount of the charged raw materials (that is, the classification yield) was 87% by weight. The finally obtained intermediate powder was observed with an optical microscope, and the ratio of the minor axis to the major axis was measured to be 0.77.

Example 2 Using the same raw material for toner pulverization as in Example 1, pulverization, low impact treatment and classification were carried out by the same production method. The impact-type airflow pulverizer having the configuration shown in FIG. 4 has a conical projection with a collision surface having a vertical angle of 55 ° (α = 55 °).
The inclination angle of the outer peripheral collision surface with respect to the vertical plane of the central axis of the accelerator tube was 10 ° (β = 10 °) (α + 2β = 75 °).
The diameter of the collision member is 100 mm (b = 100 mm), and the distance between the end of the collision surface and the outlet of the acceleration tube is 50 mm (a
= 50 mm), and the grinding chamber used was a cylindrical grinding chamber (c = 25 mm) with an inner diameter of 150 mm. The inclination of the accelerator tube in the major axis direction with respect to the vertical line was substantially 0 °.
The first classifier used was the same as in Example 1.

The pulverized raw material was supplied to a fixed amount feeder at 47.0 kg /
h, and supplied to the first classifier, and the classified coarse powder is introduced into the impinging airflow pulverizer, and has a pressure of 6.0 kg / cm ^2.
(G), after pulverization using compressed air of 6.0 Nm ³ / min, circulated again to the classifier to perform closed circuit pulverization. As a result, a finely pulverized toner product having a weight average diameter of 8.9 μm was obtained as classified fine powder. There was no fusion during pulverization, and stable operation was possible. This fine powder was processed under the same conditions using the same low impact processing apparatus as in Example 1. The processed toner is transferred to a scanning electron microscope (Hitachi, Ltd. S
(-800 type), no major change was observed in the shape as compared to before the treatment, but it was confirmed that the angular portion was reduced. Incidentally, the weight average diameter after the treatment was 8.
It was 8 μm.

The treated fine powder was introduced into a multi-segment classifier as shown in FIG. 12, and as a classified medium powder, particles having a weight average particle size of 8.2 μm (particles having a particle size of 4.0 .8
Particles containing 1% by volume and having a particle size of 12.7 μm or more.
0% by volume) in a classification yield of 88% by weight. The classified coarse powder was circulated to the pulverizing step, and the fine powder was returned to the kneading step and reused. The powder was observed with an optical microscope, and the ratio of the minor axis to the major axis was measured to be 0.76.

Example 3 Using the same toner pulverizing raw material as in Example 1, pulverization, low impact treatment and classification were carried out by the same production method. The collision-type airflow pulverizer having the configuration shown in FIG. 7 has a conical projection with a collision surface having a vertical angle of 55 ° (α = 55 °).
The inclination angle of the outer peripheral collision surface with respect to the vertical plane of the central axis of the accelerator tube was 10 ° (β = 10 °) (α + 2β = 75 °).
The diameter of the collision member is 100 mm (b = 100 mm), and the distance between the end of the collision surface and the outlet of the acceleration tube is 50 mm (a
= 50 mm), and the grinding chamber used was a cylindrical grinding chamber (c = 25 mm) with an inner diameter of 150 mm. The inclination of the accelerating tube in the long axis direction with respect to the vertical line was substantially 0 °, and the pulverized raw material supply port was used which was opened in the entire circumferential direction of the accelerating tube. The first classifier used was the same as in Example 1.

[0092] The amount of the pulverized raw material was 46.0 Kg /
h to a first classifier, and the classified coarse powder is introduced into the impinging airflow pulverizer and has a pressure of 6.0 kg / cm ^2.
(G), after pulverization using compressed air of 6.0 Nm ³ / min, circulated again to the classifier to perform closed circuit pulverization. As a result, a finely pulverized toner product having a weight average diameter of 9.0 μm was obtained as classified fine powder. There was no fusion during pulverization, and stable operation was possible. This fine powder was processed under the same conditions using the same low impact processing apparatus as in Example 1.

When the processed toner was observed with a scanning electron microscope (S-800, manufactured by Hitachi, Ltd.), no significant change was observed in the shape as compared to before the processing, but the angular portion was reduced. Was confirmed. The weight average diameter after the treatment was 8.9 μm. This treated fine powder is
Introduced into the multi-segmentation classifier No. 2 and as classified medium powder,
It has a sharp distribution with a weight average particle size of 8.2 μm (containing 0.8% by volume of particles having a particle size of 4.0 μm or less and 1.2% by volume of particles having a particle size of 12.7 μm or more). A toner was obtained with a classification yield of 86% by weight. The classified coarse powder was circulated to the pulverizing step, and the fine powder was returned to the kneading step and reused. The powder was observed with an optical microscope, and the ratio of the minor axis to the major axis was measured to be 0.76.

Example 4 Using the same toner pulverizing raw material as in Example 1, pulverization, low impact treatment and classification were performed in the same production method. That is, in the collision type airflow pulverizer, the apparatus having the configuration shown in FIG. 2 was used under the same apparatus conditions as in Example 1. The first classifier used was the same as in Example 1. 18. Pulverized raw material is fed with a fixed amount feeder.
0 Kg / h was supplied to the first classifier, and the classified coarse powder was introduced into the impingement type air current pulverizer, and the pressure was set to 6.0 kg / c.
After pulverization using m ² (G) and 6.0 Nm ³ / min compressed air, the mixture was circulated again to a classifier to perform closed circuit pulverization. As a result, the weight average diameter was 7.0 as classified fine powder.
A μm finely pulverized product for toner was obtained. There was no fusion during pulverization, and stable operation was possible.

The fine powder was subjected to a low impact device shown in FIG. 9 at a rotor rotation speed of 130 m / sec, a clearance between the liner and the rotor of 1 mm, and an outlet temperature of the device of 45 ° C.
Processed. When the processed toner was observed with a scanning electron microscope (model S-800, manufactured by Hitachi, Ltd.), no significant change was observed in the shape as compared with before the processing, but it was confirmed that the angular portion was reduced. Was. The weight average diameter after the treatment was 6.8 μm.

The treated fine powder is introduced into the multi-segment classifier shown in FIG. 12 to obtain a classified intermediate powder having a weight average particle diameter of 6.5 μm (particles having a particle diameter of 4.0 μm or less are 3.0 μm). volume%
Containing 1.0% by volume of particles having a particle size of not less than 10.08 μm) and a sharp distribution of 84% by weight. The classified coarse powder was circulated to the pulverizing step, and the fine powder was returned to the kneading step and reused. The powder was observed with an optical microscope, and the ratio of the minor axis to the major axis was measured to be 0.80.

Example 5 Using the same toner pulverization raw material as in Example 1, pulverization, low impact treatment and classification were performed in the same production method. That is, in the collision type air current pulverizer, the apparatus having the configuration shown in FIG. 4 was used under the same apparatus conditions as in Example 2. The first classifier used was the same as in Example 1. 30. Grinding raw material is fed by a quantitative feeder.
It is supplied to the first classifier at a rate of 0 Kg / h, and the classified coarse powder is introduced into the impinging airflow pulverizer, and has a pressure of 6.0 kg / c.
After pulverization using m ² (G) and 6.0 Nm ³ / min compressed air, the mixture was circulated again through a classifier to perform closed circuit pulverization. As a result, the weight average diameter was 6.9 as classified fine powder.
A μm finely pulverized product for toner was obtained. There was no fusion during pulverization, and stable operation was possible.

The fine powder was treated using the same low-impact treating apparatus as in Example 1 under the same conditions. When the processed toner was observed with a scanning electron microscope (model S-800, manufactured by Hitachi, Ltd.), no significant change was observed in the shape as compared with before the processing, but it was confirmed that the angular portion was reduced. Was. The weight average diameter after the treatment was 6.8 μm.

The fine powder thus treated was introduced into the multi-segment classifier shown in FIG. 12 to obtain a classified intermediate powder having a weight average particle diameter of 6.5 μm (particles having a particle diameter of 4.0 μm or less were 3.0 μm). volume%
Containing 1.0% by volume of particles having a particle size of not less than 10.08 μm) and a sharp distribution of 84% by weight. The classified coarse powder was circulated to the pulverizing step, and the fine powder was returned to the kneading step and reused. The powder was observed with an optical microscope, and the ratio of the minor axis to the major axis was measured to be 0.80.

Example 6 Fine powder having a weight average particle size of 8.9 μm obtained in the same manner as in Example 2 was mixed with a liner using a low impact treatment apparatus shown in FIG. 11 at a rotation speed of a rotor blade of 110 m / sec. The treatment was performed under the conditions of a rotor blade clearance of 2 mm and an outlet temperature of the device of 40 ° C. When the processed toner was observed with a scanning electron microscope (model S-800, manufactured by Hitachi, Ltd.), no significant change was observed in the shape as compared with before the processing, but it was confirmed that the angular portion was reduced. Was.
Incidentally, the weight average diameter after the treatment was 8.8 μm.

The treated fine powder was classified by a multi-segment classifier in the same manner as in Example 1. The classified medium powder had a sharp distribution with a weight average particle size of 8.2 μm. It had excellent performance as a toner. The classification yield at this time was 86% by weight, and the obtained medium powder was observed with an optical microscope, and the ratio of the minor axis to the major axis was measured to be 0.75.

Comparative Example 1 Using the same raw material for toner pulverization as in Example 1, pulverization and classification were performed according to the flowchart of FIG. The crusher shown in FIG. 14 was used as a collision-type airflow crusher, and a crusher having a plane having a collision surface perpendicular to the longitudinal direction of the acceleration tube was used. The diameter of the collision member is 90 mm (b = 90 m
m), and the distance between the end of the collision surface and the outlet of the accelerator is 50 m
m (a = 50 mm), and the shortest distance from the crushing chamber wall is 2
0 mm (c = 20 mm), and the grinding chamber was box-shaped.

The first classification means and the second classification means used a dispersion separator DS5UR (manufactured by Nippon Pneumatic Industries, Ltd.). 1 crushed raw material with constant feeder
The powder was supplied to DS5UR at a rate of 5.0 Kg / h, and the classified coarse powder was introduced into the impinging airflow pulverizer, and the pressure was 6.0 Kg.
/ Cm ² (G), pulverized using compressed air of 6.0 Nm ³ / min, and then circulated again to a classifier to perform closed circuit pulverization. As a result, the weight average diameter of the classified fine powder was 7.
An 8 μm finely pulverized product for toner was obtained. Supply amount of 15kg /
h, the volume average diameter of the obtained fine powder increases, and fusion of the pulverized material, aggregates and coarse particles start to occur on the collision member, and the fused material clogs the raw material supply port of the acceleration tube. In some cases, stable operation was not possible.

When the fine powder was observed with a scanning electron microscope (S-800, manufactured by Hitachi, Ltd.), many angular projections were observed. This fine powder is converted into a second classifier DS
-5 UR at a rate of 15.0 kg / h, and a weight average particle size of 8.4 μm (particles having a particle size of 4.0
2. particles containing 1% by volume and having a particle size of 12.7 μm or more.
(Containing 2% by volume) of a medium powder having a rather broad particle size distribution with a classification yield of 68% by weight. The finally obtained intermediate powder was observed with an optical microscope, and the ratio of the minor axis to the major axis was measured to be 0.65. Compared with Examples 1 to 3, the pulverization amount and the classification yield were inferior, and the surface condition of the toner had sharp projections.

Comparative Example 2 Using the same toner pulverization raw material as in Example 1, pulverization and classification were carried out by the production method shown in FIG. A crusher similar to that of Comparative Example 1 (pressure: 6.0 kg / cm) was used as a collision type air crusher.
² (G), using compressed air of 6.0 Nm ³ / min), and a dispersion separator DS5UR (manufactured by Nippon Pneumatic Industries, Ltd.) was used as the first and second classification means.

The pulverized raw material was supplied at a rate of 8.0 kg / h to obtain a fine powder having a weight average particle size of 6.4 μm. Observation of this fine powder with a scanning electron microscope (S-800, manufactured by Hitachi, Ltd.) revealed many angular projections. 8.0 kg of this fine powder was added to DS-5UR as a second classifying means.
/ H, and a weight average particle diameter of 6.8 μm (contains particles having a particle diameter of 4.0 μm or less 5.3% by volume and particles having a particle diameter of 10.08 μm or more 4.0% by volume. ) Classification yield of medium powder having a rather broad particle size distribution is 60
Obtained in% by weight. The finally obtained middle powder was observed with an optical microscope, and the ratio of the minor axis to the major axis was measured to be 0.70. Compared with Examples 4 and 5, the pulverization amount and the classification yield were inferior, and the surface condition of the toner had sharp projections.

Example 7 100 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 Henschel mixer (FM-75 type,
After mixing well with Mitsui Miike Kakoki Co., Ltd.
Kneading and dispersing were performed with a twin-screw kneader (PCM-30, manufactured by Ikegai Iron Works Co., Ltd.) set to 0 ° C. The obtained kneaded product was cooled and coarsely pulverized to 1 mm or less with a hammer mill to obtain a coarse powder for toner production. Fig. 1
The pulverized low impact treatment and classification were carried out by the production method shown in (1).

The impingement type air current pulverizer uses an apparatus having the structure shown in FIG. 4 and has a conical projection having an apex angle of 55 ° (α = 55 °). The inclination angle of the central axis with respect to the vertical plane was 10 ° (β = 10 °) (α
+ 2β = 75 °). The diameter of the collision member is 100 mm
(B = 100 mm), the distance between the end of the collision surface and the outlet of the accelerating tube was 50 mm (a = 50 mm), and the grinding chamber used was a cylindrical grinding chamber (c = 25 mm) having an inner diameter of 150 mm. The inclination of the accelerator tube in the major axis direction with respect to the vertical line was substantially 0 °. The first classifier used was the same as in Example 1.

The pulverized raw material was reduced to 43.0 Kg /
h to a first classifier, and the classified coarse powder is introduced into the impinging airflow pulverizer and has a pressure of 6.0 kg / cm ^2.
(G), after pulverization using compressed air of 6.0 Nm ³ / min, circulated again to the classifier to perform closed circuit pulverization. As a result, a finely pulverized toner product having a weight average diameter of 8.0 μm was obtained as classified fine powder. There was no fusion during pulverization, and stable operation was possible. This fine powder was processed under the same conditions using the same low impact processing apparatus as in Example 1. The processed toner is transferred to a scanning electron microscope (Hitachi, Ltd. S
(-800 type), no major change was observed in the shape as compared to before the treatment, but it was confirmed that the angular portion was reduced. The weight average diameter after the treatment was 7.
It was 8 μm.

The treated fine powder was introduced into a multi-segment classifier shown in FIG. 12 and classified as a medium powder having a weight average particle diameter of 8.2 μm (particles having a particle diameter of 4.0 μm or less were 0.2 μm or less). 1.5% of particles containing 6% by volume and having a particle size of 12.7 μm or more.
(% By volume) was obtained with a classification yield of 80% by weight. The classified coarse powder was circulated to the pulverizing step, and the fine powder was returned to the kneading step and reused. This powder was observed with an optical microscope, and the ratio of the minor axis to the major axis was measured to be 0.75.

Comparative Example 3 Using the same toner pulverization raw material as in Example 7, pulverization and classification were performed according to the flowchart of FIG. The pulverizer shown in FIG. 14 was used as a collision-type airflow pulverizer, and a pulverizer whose collision surface was perpendicular to the longitudinal direction of the accelerating tube was used. The diameter of the collision member is 90mm (b = 90mm)
And the distance between the end of the collision surface and the exit of the acceleration tube is 50 mm
(A = 50 mm), and the shortest distance from the crushing chamber wall is 20
mm (c = 20 mm), and the grinding chamber was box-shaped. The first classification means and the second classification means used a dispersion separator DS5UR (manufactured by Nippon Pneumatic Industries, Ltd.).

The pulverized raw material was reduced to 18.0 kg /
h and supplied to a DS5UR, and the classified coarse powder was introduced into the impinging air-flow pulverizer, and the pressure was 6.0 kg / cm ^2.
(G), after pulverization using compressed air of 6.0 Nm ³ / min, circulated again to the classifier to perform closed circuit pulverization. As a result, a finely pulverized toner product having a weight average diameter of 7.5 μm was obtained as classified fine powder. When the supply amount is increased to 18 kg / h or more, the volume average diameter of the obtained fine powder increases,
Fusing, agglomerates, and coarse particles of the pulverized material began to occur on the collision member, and the fused material sometimes clogged the raw material supply port of the acceleration tube, and stable operation was not possible.

When the fine powder was observed with a scanning electron microscope (S-800, manufactured by Hitachi, Ltd.), many angular projections were observed. This fine powder is subjected to a second classifying means D
S-5UR was supplied at a rate of 18.0 kg / h, and the weight average particle diameter was 8.0 μm (particles having a particle diameter of 4.0 μm or less were 1.
A medium powder having a slightly broad particle size distribution (containing 5% by volume and 3.3% by volume of particles having a particle size of 12.7 μm or more) was obtained with a classification yield of 62% by weight. The finally obtained intermediate powder was observed with an optical microscope, and the ratio of the minor axis to the major axis was measured to be 0.65. Compared with Example 7, the pulverization amount and the classification yield were inferior, and the surface condition of the toner had sharp projections.

[0101]

According to the method for producing a toner for developing an electrostatic charge image of the present invention, a toner having a small particle diameter can be produced efficiently by a specific jet mill having high impact and good pulverization efficiency, and By the low impact treatment process, a good quality toner having excellent fluidity can be obtained. Further, there is an advantage that it is possible to prevent the occurrence of fusion, aggregation, and coarsening of the pulverized toner particles in the toner manufacturing process, prevent device-like abrasion due to toner components, and perform continuous and stable production. In addition, by using the toner manufacturing method of the present invention, an electrostatic image having a stable and high image density, excellent durability, and excellent predetermined particle size free from image defects such as fog and poor cleaning can be obtained as compared with the conventional method. A developing toner can be obtained at low cost. In particular, there is an advantage that a toner having a weight average particle size of 9 μm or less can be effectively obtained.

[0102]

[Brief description of the drawings]

FIG. 1 is a flowchart for explaining a manufacturing method of the present invention.

FIG. 2 is a schematic cross-sectional view of a specific example of an impingement airflow pulverizing means for performing the production method of the present invention.

FIG. 3 is a cross-sectional plan view of the grinding chamber in FIG.

FIG. 4 is a schematic sectional view showing another specific example of the impingement type air current pulverizing means for carrying out the production method of the present invention.

FIG. 5 is a sectional view taken along line A-A 'in FIG.

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

[0103]

FIG. 7 is a schematic cross-sectional view showing another specific example of the impingement type air current pulverizing means for performing the production method of the present invention.

8 is a sectional view taken along line C-C 'in FIG.

FIG. 9 is a schematic cross-sectional view showing a specific example of a low-impact processing apparatus for performing the manufacturing method of the present invention.

FIG. 10 is a view showing a positional relationship between a learner and a rotor of the apparatus shown in FIG. 9;

FIG. 11 is a schematic cross-sectional view showing another specific example of the low impact processing apparatus for performing the manufacturing method of the present invention.

[0104]

FIG. 12 is a sectional view of a specific example of a classification device used in the present invention.

FIG. 13 is a flowchart for explaining a conventional manufacturing method.

FIG. 14 is a schematic cross-sectional view of a collision-type airflow pulverizing means used in a conventional manufacturing method.

FIG. 15 is a schematic sectional view of another collision-type airflow pulverizing means used in a conventional production method.

FIG. 16 is a schematic cross-sectional view of another collision-type airflow pulverizing means used in a conventional manufacturing method.

FIG. 17 is a schematic sectional view of another collision-type airflow pulverizing means used in a conventional production method.

[0105]

[Description of sign]

 1: crushed material supply port 2: compressed gas supply nozzle 3: acceleration tube 4: collision member 5: discharge port 6: crushing chamber side wall 7: crushed material 8: crushing chamber 11: crusher wall 13: acceleration pipe outlet 14: protrusion Central part 15: Outer collision surface 16: Collision surface

21: Acceleration tube 22: Acceleration tube throat part 23: High pressure gas ejection nozzle 24: Pulverized material supply port 25: Pulverized material supply cylinder 26: High pressure gas supply port 27: High pressure gas chamber 28: High pressure gas introduction pipe 29: Acceleration tube outlet 30: Collision member 32: Pulverization chamber side wall

33: pulverized material outlet 34: pulverizing chamber 35: Laval nozzle 36: accelerating tube throat section 37: accelerating tube outlet 38: return path 39: raw material supply port 40: inlet 41: jacket 42: return closing valve 43: rotating shaft 44: Casing 45: Liner

46: blower blade 47: rotor 48: outlet 49: product outlet 51: casing 52: rotor 53: blade 54: liner 55: processing area 56: input raw material 57: inflow air 58: supply port 59: spiral chamber

60: Distributor 61: Outlet 111: Outlet 112: Outlet 113: Outlet 114: Inlet tube 115: Inlet tube 116: Material supply nozzle 117: Classification edge 118: Classification edge 119: Inlet edge 120 : First gas introduction adjusting means 121: Second gas introduction adjusting means

122: Side wall 123: Lower wall 124: Side wall 125: Lower wall 126: Coanda block 127: Upper wall 128: Static pressure gauge 129: Static pressure gauge 130: Trajectory of particles

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Satoshi Mitsumura 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) References JP-A-3-287173 (JP, A) JP JP-A-5-309287 (JP, A) JP-A-3-60749 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 9/087 B02C 19/06

Claims (3)

(57) [Claims] 1. A mixture containing at least a binder resin and a colorant is melt-kneaded to obtain a kneaded product, the obtained kneaded product is cooled to obtain a cooled product, and the obtained cooled product is pulverized by a pulverizing means. To obtain a pulverized product, classify the obtained pulverized product into coarse powder and fine powder by a first airflow classification means, and finely pulverize the classified coarse powder by a collision type airflow pulverization means to produce a fine powder. A second airflow classifying means for classifying a powder having a prescribed particle size from the generated fine powder and producing an electrostatic image developing toner from the classified powder having a prescribed particle size; In the method for producing a toner, the collision-type airflow pulverizing means is a pulverizer having an accelerating tube for conveying and accelerating an object to be pulverized by a high-pressure gas, and a pulverizing chamber for pulverizing the object to be pulverized, The object to be pulverized, supplied into the accelerating tube and accelerated, is discharged into the pulverizing chamber through the outlet of the accelerating tube. And primary pulverized at a protrusion of a collision member having a collision surface provided opposite to an opening surface of an outlet of the acceleration tube, and a primary pulverized material obtained by primary pulverization is provided on an outer periphery of the protrusion. The secondary pulverization is performed on the collision surface, and the secondary pulverized material is further subjected to tertiary pulverization on the side wall in the pulverization chamber to perform a fine pulverization step, and then circulated to the first airflow classification means, and the first airflow classification is performed. Apart from the milling step in the classified fine powder by means by Rukoto given short time relatively low impact than the collision type air pulverizer means, said
After reducing the angular projections of the fine powder , the second
A method for producing a toner for developing an electrostatic image, wherein the particle size is adjusted by an airflow classifier. 2. The method according to claim 1, wherein the apex angle of the central portion of the collision member protruding from the collision surface is α (°), and the inclination angle β (°) of the outer peripheral collision surface with respect to the vertical plane of the central axis of the acceleration tube. The method according to claim 1, wherein α and β satisfy the following expressions: 0 <α <90, β> 030 ≦ α + 2β ≦ 90. 3. The means for imparting a relatively lower impact than said impingement-type air-grinding means comprises: (i) for imparting an impact between a rotating rotor, blade or hammer and a liner opposed to any of them. 3. The method for producing a toner according to claim 1 or 2, wherein (ii) a device for applying an impact between a number of rotating pins.