JP3220918B2 - Method and apparatus for manufacturing 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 and apparatus for efficiently pulverizing and classifying solid particles having a binder resin to obtain a toner for developing an electrostatic image having a predetermined particle size.

[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 this toner has become even more severe, and the particle size of the toner has become smaller. There has been a growing demand for sharp, powder-free products with little fines.

[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. Charge control agent, and JP-A-54-4214
In the so-called one-component developing method disclosed in JP-A-55-18656, various magnetic materials for imparting transportability and the like to the toner itself are used. And a fluidity-imparting agent are dry-mixed, then melted and kneaded with a general-purpose kneading device such as a roll mill or extruder, cooled and solidified, and then various types of crushing devices such as a jet air flow crusher and a mechanical impact crusher. By pulverizing and classifying using a pneumatic classifier, the particle size required for the toner is made uniform. If necessary, a fluidizing agent, a lubricant and the like are dry-mixed to form a toner. When used in the two-component developing method, various magnetic carriers and a toner are mixed and then used for image formation.

As described above, in order to obtain toner particles which are fine particles, a method shown in the flowchart of FIG. 15 or a method using a part of the method is generally adopted.

[0005] The coarsely crushed toner is supplied to the first classifying means continuously or sequentially and classified, and the classified coarse powder mainly composed of coarse particles having a specified particle size or more is sent to the crushing means and crushed. Is again circulated to the first classification means.

[0006] The finely pulverized toner mainly composed of particles within the specified particle size range and particles not larger 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. 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 pulverizers are used. For pulverizing a coarsely pulverized toner mainly composed of a binder resin, a jet air flow type pulverizer using a jet air flow as shown in FIG. An air-flow pulverizer is used.
As described above, the pulverizer shown in FIG.
There are problems such as a low processing capacity, generation of a fusion product of pulverized material on the collision surface, and frequent replacement due to local wear of the collision member.

For example, in the collision type air flow pulverizer shown in FIG. 16, a collision member 24 is provided opposite an outlet 23 of an acceleration tube 22 to which a high-pressure gas supply nozzle 21 is connected.
With the high-pressure gas supplied, the powder raw material is sucked into the acceleration tube 22 from the powder raw material supply port 40 communicated in the middle of the acceleration tube 22, and the powder raw material is injected together with the high-pressure gas to collide with the collision member 24. It collides with the surface and is crushed by the impact.

However, in the collision type air-flow pulverizer shown in FIG. 16, since the supply port 40 for the pulverized material is provided in the middle of the accelerating pipe 22, the pulverized substance sucked and introduced into the accelerating pipe 22 cannot be pulverized. Immediately after passing through the pulverized material supply port 40, it is dispersed in the high-pressure airflow while being changed in the flow path toward the outlet of the acceleration tube by the high-pressure airflow ejected from the high-pressure gas supply nozzle 21 and rapidly accelerated. In this state, the relatively coarse particles of the material to be crushed flow through the low flow portion in the acceleration tube due to the effect of the inertial force,
Relatively fine particles flow in the high-flow portion of the accelerating tube, so they are not sufficiently uniformly dispersed in the high-pressure airflow. Collision and partial collision with the member are likely to occur, so that the pulverization efficiency is likely to be reduced and the processing capacity is likely to be reduced.

In the vicinity of the collision surface 29, a portion having a high dust concentration composed of the material to be crushed and the crushed material is likely to be locally generated. Therefore, when the material to be crushed contains a low melting point substance such as a resin, Fusing, coarsening, agglomeration, etc. of the material to be ground are likely to occur. In addition, when the object to be ground has abrasion properties, local powder wear is likely to occur on the collision surface of the collision member and the accelerating tube, and the frequency of replacement of the collision member is increased, so that the production is continuously and stably performed. There was a point to improve in terms of aspects.

The tip of the collision surface of the collision member has an apex angle of 11
Conical shape having 0 to 175 ° (JP-A 1-25
No. 4266) and a collision plate shape having a projection on a plane where a collision surface intersects perpendicularly with the extension of the central axis of the collision member (Japanese Utility Model Application Laid-Open No. 1-148740). In these crushers, the local increase in dust concentration near the collision surface can be suppressed, so that the fusion, coarsening, and agglomeration of the crushed material can be somewhat moderated, and the crushing efficiency is slightly improved. However, further improvements are desired.

For example, when obtaining a toner having a volume average particle diameter of 8 μm and a weight percentage of particles of 4 μm or less of 1% or less, an impact-type pulverizer equipped with a classification mechanism for removing a coarse powder region. Alternatively, the raw material is pulverized to a predetermined average particle size by a pulverizing means such as a jet pulverizer and classified, and the pulverized material after removing the coarse powder is subjected to another classifier to remove the fine powder and remove the desired medium powder. Gaining body.

The volume average particle size referred to here is the value of Coulter Counter T manufactured by Coulter Electronics (USA).
It is data measured using an aperture of 100 μm for type A-II.

[0014] In such a conventional method, there is a problem in that the second classifying means for removing fine powder has to send a particle group from which coarse particles having a certain particle size or more are completely removed. , The load of the crushing means increases,
Processing volume is reduced. In addition, in order to completely remove a coarse particle group having a specific particle size or more, excessive pulverization is inevitable, and as a result, a phenomenon such as a decrease in yield in the second classification means for removing fine powder in the next step is caused. There is a problem.

In the second classification means for removing fine powder, aggregates composed of ultrafine particles may be generated, and it is difficult to remove the aggregates as fine powder. In this case, the aggregates are mixed into the final product, and as a result, it is difficult to obtain a product having a fine particle size distribution. In addition, the aggregates are broken down in the toner to become extremely fine particles, which causes deterioration in image quality.

Even if a desired product having a fine particle size distribution can be obtained under the conventional method, the process becomes complicated, the classification yield is reduced, the production efficiency is low, and the cost is high. It is inevitable to become. This trend is
The smaller the predetermined particle size, the more noticeable.

In particular, when the volume average particle size becomes 8 μm or less,
This tendency becomes more pronounced.

[0018]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for solving the above-mentioned problems in a conventional method for manufacturing a toner for developing an electrostatic image.

An object of the present invention is to provide a manufacturing apparatus for efficiently manufacturing an electrostatic image developing toner.

An object of the present invention is to provide a production method for efficiently producing a toner for developing an electrostatic image having a fine particle size distribution and an apparatus therefor.

According to the present invention, a mixture containing a binder resin, a colorant and an additive is melt-kneaded, and after cooling the melt-kneaded product,
It is an object of the present invention to provide a method and an apparatus for efficiently and efficiently producing a particle product (used as a toner) having a fine predetermined particle size distribution from a group of solid particles generated by pulverization.

An object of the present invention is to provide a method for efficiently producing a toner for developing electrostatic images having a weight average particle diameter of 3 to 10 μm (preferably 3 to 9 μm) and an apparatus therefor.

[0023]

According to the present invention, a mixture containing at least a binder resin and a colorant is melt-kneaded, the kneaded product is cooled, and the cooled product is pulverized by a pulverizing means to obtain a pulverized product. After that, the pulverized material is classified into coarse powder and fine powder by the first classifying means, and the classified coarse powder is finely pulverized by the impingement airflow pulverizing means to produce fine powder. A method of producing a toner for developing an electrostatic image from a powder having a predetermined particle size within a predetermined particle size range by circulating through a first classifying means and introducing the classified fine powder into a second classifying means; The impingement-type airflow pulverizing means has an accelerating tube for conveying and accelerating the supplied coarse powder by high-pressure gas, and a pulverizing chamber for finely pulverizing the coarse powder; To supply the material to be ground to the inside of the acceleration tube between the acceleration tube outlet and the acceleration tube side wall portion The opening ratio of the crushed object supply port at the side wall portion having the crushed object supply port is 20% with respect to the acceleration pipe area of the acceleration pipe section having the crushed object supply port. %; A collision member having a collision surface provided opposite to the opening surface of the outlet of the acceleration tube is provided in the grinding chamber; the grinding chamber is configured to pulverize coarse powder pulverized by the collision member. A side wall for further crushing the object by collision, and a closest distance L between the side wall and the edge of the collision member.
₁ is shorter than the closest distance L ₂ between the grinding chamber front wall facing the impact surface and the edge of the collision member, in the pulverizing chamber, pulverization of coarse powder in the collision surface and the side wall of the impact member And after further pulverization of the coarse powder,
The fine powder circulated to the classification means and introduced by the first classification means is introduced into a multi-division classification area which is fractionated into at least three, which is the second classification means, and the particles are formed into a curved line by the Coanda effect. Then, the coarse powder mainly composed of particles having a predetermined particle size or more is divided and collected in the first fractionation area, and the medium powder mainly composed of particles having a predetermined particle diameter is collected in the second fractionation area. The body is divided and collected, and a fine powder mainly composed of particles having a predetermined particle size or less is divided and collected in a third fractionation area, and the classified coarse powder is subjected to the pulverizing means or the first classifying means. And a method for producing a toner.

Further, the present invention provides a first classifying means for classifying the pulverized material, a pulverizing means for pulverizing the coarse powder classified by the first classifying means, and a pulverizing means for pulverizing the powder pulverized by the pulverizing means. Introducing means for introducing into the first classifying means, and second division means as the second classifying means for classifying the fine powder classified by the first classifying means into at least coarse powder, medium powder, and fine powder by the Coanda effect. In a toner manufacturing apparatus having a classification unit and a supply unit for supplying the coarse powder classified by the multi-division classification unit to the pulverization unit or the first classification unit, the pulverization unit converts the supplied coarse powder An accelerating tube for conveying and accelerating with a high-pressure gas, and a pulverizing chamber for finely pulverizing coarse powder; the accelerating tube is provided at an accelerating tube side wall between the accelerating tube throat portion and the accelerating tube outlet. Pulverization for supplying the pulverization object into the acceleration tube The opening ratio of the material supply port at the side of the accelerating pipe having the supply port and the material supply port is 20% or more with respect to the area of the acceleration pipe at the part having the material supply port. Yes, a crushing chamber is provided with a collision member having a collision surface provided opposite to the opening surface of the outlet of the acceleration tube; the crushing chamber crushes the coarse powder crushed by the collision member by collision. Further, a closest distance L ₁ between the side wall and the edge of the collision member is defined by a closest distance L ₁ between the front wall of the grinding chamber facing the collision surface and the edge of the collision member. _{The present} invention relates to an apparatus for producing a toner, which is shorter than ₂ .

Hereinafter, the present invention will be described more specifically.

FIG. 1 is an example of a flowchart showing the outline of the manufacturing method of the present invention. In the present invention, a predetermined amount of 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 into the pulverizing means, pulverized, and after pulverization, introduced into the first classifying means.
The predetermined amount of the fine powder is supplied to the second classification means and classified into at least a fine powder, a medium powder, and a coarse powder. A predetermined amount of the coarse powder is introduced into the pulverizing means or the first classifying means. The classified medium powder is used as a toner as it is, or is mixed with an additive such as hydrophobic colloidal silica, and then used as a toner. The classified fine powder is generally supplied to a melt-kneading process for producing a pulverized raw material and reused or discarded.

In the production method of the present invention, by controlling the classification and pulverization conditions, it is possible to efficiently produce a small particle size toner having a weight average particle size of 3 to 10 μm (preferably 3 to 9 μm). it can. FIG. 2 shows an example of the device system of the present invention.

In this apparatus system, the pulverized raw material to be used as the toner powder raw material is introduced into the first classifier 109 via the first quantitative feeder 102, and the classified fine powder is collected via the collection cyclone 107. It is sent to the second fixed-quantity feeder 110, and then introduced into the multi-divided classifier 101 via the fine powder supply nozzle 116 via the vibration feeder 103. The coarse powder classified by the first classifier 109 is sent to the pulverizer 108 via the collection cyclone 106 to be pulverized, and then re-introduced into the first classifier 109 together with the newly input pulverized raw material.

FIGS. 4 to 9 show crushing means used in the present invention.
1 shows a collision type airflow pulverizer of the type shown in FIG.

In FIG. 4, the object 80 supplied from the object supply pipe 19 is supplied with respect to the area of the accelerating tube at the portion having the object supply port 10 formed on the side wall of the acceleration tube 1. The material to be ground 10 is supplied into the acceleration tube 1 from the material to be ground 10 having an opening ratio of 5% or more (preferably 20% or more).

It is preferable that the center axis of the high-pressure gas jet nozzle 3 and the center axis of the acceleration tube 1 are substantially coaxial.

On the other hand, the high-pressure gas is introduced from the high-pressure gas supply port 7, passes through the high-pressure gas chamber 2, preferably through a plurality of high-pressure gas introduction pipes 8, and from the high-pressure gas ejection nozzle 3 to the acceleration pipe outlet 11. Spouts while expanding rapidly in the direction. At this time, the pulverized material 80 is entrained by the gas coexisting with the
From 0, the gas is sucked in the direction of the accelerating tube outlet 11 and rapidly accelerated while being uniformly mixed with the high-pressure gas, and is uniformly distributed on the collision surface 16 of the collision member 4 facing the accelerating tube outlet 11 without unevenness of the dust concentration. They collide in a mixed flow. The impact force generated at the time of the collision is sufficiently dispersed individual particles (object to be crushed 80).
Therefore, very efficient pulverization can be performed.

The pulverized material pulverized on the collision surface 16 of the collision member 4 further collide with the side wall 14 of the pulverization chamber 5 in a secondary collision (or
The crushed material is discharged from the crushed material discharge port 6 described behind the collision member 4.

The collision surface 16 of the collision member 4 has a cone shape as shown in FIG. 4, or the collision surface 16 has a conical projection as shown in FIGS. 14 (a) and 14 (b). Is preferable in order to uniformly disperse the pulverized material in the pulverization chamber 5 and to efficiently perform the secondary collision with the side wall 14. Further, when the pulverized material discharge port 6 is located behind the collision member 4, the pulverized material can be smoothly discharged.

FIG. 5 is an enlarged view of the grinding chamber. In FIG. 5, the closest distance L ₁ between the edge 15 of the collision member 4 and the side wall 14 is shorter than the closest distance L ₂ between the front wall 17 and the edge 15 of the collision member 4. This is important so that the powder concentration in the grinding chamber near the pipe outlet 11 is not increased. Further, recently because contact distance L ₁ is shorter than the closest distance L _2, it is possible to perform efficiently the secondary collision of the pulverized material in the side wall 14. Also, the collision member 4 is 9
Slope θ ₁ smaller than 0 ° (more preferably, 55 °
87.5 °, more preferably an inclination θ of 60 ° to 85 °
It is preferable to have the slope having the condition ₁ ) as the collision surface in order to uniformly disperse the pulverized material and efficiently perform the secondary collision on the side wall 14.

As shown in FIG. 16, the collision surface 29 is
In contrast to a crusher having a 90-degree flat collision member 24, a crusher having an inclined collision surface, when crushing a resin or a sticky substance, adheres to the crushed object, Agglomeration and coarsening hardly occur, and pulverization at a high dust concentration becomes possible. In addition, in the case of the abraded material to be crushed, wear generated on the inner wall of the accelerating tube and the collision surface of the collision member is not locally concentrated, so that the life can be extended and stable operation can be performed.

The inclination of the accelerating tube 1 in the major axis direction is preferably within a range of 0 to 45 ° with respect to the vertical direction, so that the crushed material 80 is not blocked at the crushed material supply port 10. Can be processed.

If the material to be ground has poor fluidity, a conical member is provided below the material supply pipe 19.
Although it is a small amount, it tends to stay at the lower part of the cone-shaped member, and the inclination of the acceleration tube 1 is 0 to the vertical direction.
Within the range of 20 ° (more preferably 0 to 5 °), there is no stagnation of the material to be ground in the lower cone portion, and the material to be ground can be smoothly supplied to the acceleration tube.

The shape of the crushing chamber is as shown in FIG.
It is preferable that the side wall 14 has a substantially circular or elliptical shape in the cross section taken along the line CC ′ in the point of uniformity of pulverization and smooth discharge of the pulverized material. Further, the pulverized material discharge outlet is preferably provided behind the collision member in order to smoothly discharge the pulverized material.

FIG. 6 is a sectional view taken along the line AA 'in FIG. It is understood from FIG. 6 that the material to be ground 80 is smoothly supplied to the acceleration tube 1. The distance L ₂ between the outermost end 15 of the collision surface 16 of the collision member 4 facing the surface of the acceleration tube outlet 11 or the front wall, which intersects perpendicularly with the extension of the acceleration tube center axis,
The diameter of the collision member 4 is preferably in the range of 0.2 to 2.5 times in terms of the pulverization efficiency, and more preferably in the range of 0.4 to 1.0 times. Distance in L ₂ is less than 0.2 times, there are cases where dust concentration in the vicinity of the impact surface 16 becomes abnormally high and, if exceeding 2.5 times, weakened impact force, resulting in lowered grinding efficiency Tend to.

The shortest distance L ₁ between the outermost end 15 of the collision member 4 and the side wall 14 is preferably in the range of 0.1 to 2.0 times the diameter of the collision member 4. If the pressure is less than 0.1 times, the pressure loss during passage of the high-pressure gas is large, the pulverization efficiency tends to decrease, and the flow state of the pulverized material tends not to be smooth. The effect of the secondary collision of the object to be ground on the side wall 14 is reduced, and the efficiency of the grinding tends to be reduced.

More specifically, the length of the accelerating tube is 50 to
The diameter of the collision member 4 is preferably 30 to 30 mm.
It is preferred to have 0 mm. Furthermore, it is preferable that the collision surface 16 and the side wall 14 of the collision member 4 are formed of ceramic from the viewpoint of durability.

FIG. 7A is a cross-sectional view taken along the line BB 'in FIG. 4 when the supply port 10 for the material to be ground is annular. In this case, the opening ratio of the supply port of the material to be ground is 100%. FIG.
In (a), the distribution state of the crushed object in the vertical plane with respect to the vertical direction of the crushed object supply port 10 passing through the crushed object supply port 10 is such that the greater the inclination of the acceleration tube 1 with respect to the vertical direction, the more the distribution. Because of the bias, the smaller the slope, the more uniform the distribution. The best inclination of the accelerating tube 1 in the range of 0 to 5 ° was confirmed by changing the accelerating tube 1 to a transparent acrylic resin accelerating tube for internal observation. FIG. 7B is a cross-sectional view taken along the line BB ′ in FIG. 4 when the material supply port 10 is formed of four tubes. In this case, the opening ratio of the supply port of the pulverized material is, for example, 2
0%.

In the present invention, between the throat portion 9 of the acceleration tube 1 having a Laval shape and the acceleration tube outlet 11, the entire circumference of the acceleration tube in a vertical plane with respect to the vertical direction or two or more acceleration tubes (preferably, (Four or more) pulverized material supply ports are preferably provided.

FIG. 8 is a sectional view taken along the line CC ′ in FIG. 4. In FIG. 8, the pulverized material is discharged rearward through the pulverizing chamber 5 between the collision member support 18 and the side wall 14. .

FIG. 9 is a sectional view taken along the line DD 'in FIG. In FIG. 9, two high-pressure gas introduction pipes 8 are provided, but depending on the case, the number of high-pressure gas introduction pipes 8 may be one or three or more.

As a first classifying means used in the present invention, an airflow classifier is used. For example, a DS type classifier manufactured by Nippon Pneumatic Industries Co., Ltd., a micron separator manufactured by Hosokawa Micron Co., Ltd. and the like can be mentioned. Preferably, an airflow classifier shown in FIG. 10 is used to improve the classification accuracy of fine powder and coarse powder.

FIG. 11 is a sectional view taken along the line FF 'in FIG.

In FIG. 10, the supply pipe of the object to be pulverized of the impingement type air flow pulverizer is connected to a hopper having a coarse powder discharge port of the air flow classifier, and the pulverized material discharge port 6 of the impingement type air current pulverizer is connected.
And a powder supply pipe 24 of an airflow classifier.

In FIG. 10, reference numeral 36 denotes a cylindrical main body casing, 31 denotes a lower casing, and a hopper 32 for discharging coarse powder is connected to a lower portion thereof. A classifying chamber 28 is formed inside the main body casing 36. An upper part of the classifying chamber 28 has an annular guide chamber 26 attached to an upper part of the main body casing 36 and a conical (umbrella-shaped) upper part whose central part is higher. It is closed by a cover 25.

A plurality of introduction louvers 27 arranged in the circumferential direction are provided on a partition wall between the classifying chamber 28 and the guide chamber 26, and the powder material and the air fed into the guide chamber 26 are supplied from between the introduction louvers 27. It is swirled into the classifying chamber 28 to flow therethrough. The air and the powder material flowing in the guide chamber 26 via the supply pipe 24 are preferably uniformly distributed to the introduction louvers 27 for accurate classification. It is necessary that the flow path to reach the introduction louver 27 has a shape that does not easily cause concentration due to centrifugal force.
Are connected from above in a direction perpendicular to the horizontal plane of the classifying chamber 28, but the invention is not limited to this.

In this way, the air and the powder material are supplied to the classifying chamber 28 through the introduction louver 27, and when the air and the powder material are supplied to the classification chamber 28 through the introduction louver 27, the air and the powder material are significantly dispersed and uniform compared to the conventional method. The property can be improved. Further, the introduction louver 27 is movable, and the louver gap can be adjusted.

A classifying louver 37 arranged in the circumferential direction is provided at the lower part of the main body casing 36, and the classifying chamber 28 is externally provided.
Classification air that causes a swirling flow is introduced through a classification louver 37.

At the bottom of the classifying chamber 28, a conical (umbrella-shaped) classifying plate 29 whose central portion is high is provided, and a coarse powder discharge port 38 is formed around the outside of the classifying plate 29. A fine powder discharge pipe 30 having a fine powder discharge port 81 is connected to the center of the classifying plate 29, and the lower end of the fine powder discharge pipe 30 is bent into an L-shape. Position outside. Further, the fine powder discharge pipe 30 is connected to a suction fan 34 via a fine powder collecting means 33 such as a cyclone or a dust collector, and the suction fan 34 applies a suction force to the classifying chamber 28 so that the space between the classifying louvers 37 is removed. The swirling flow required for classification is caused by the suction air flowing into the classification chamber 28.

The air classifier shown in the present embodiment has the above-described structure. When a powder material is supplied from the supply pipe 24 into the guide chamber 26 together with air, the air containing the powder material is supplied from the guide chamber 26 to the guide chamber 26. After passing between the introduction louvers 27, it is swirled into the classifying chamber 28 while flowing at a uniform concentration while being dispersed.

The powder material which has flowed into the classifying chamber 28 while swirling is swirled by a suction fan 34 connected to the fine powder discharge pipe 30 along a suction air flow flowing from between the classifying louvers 27 below the classifying chamber. The coarse powder is centrifuged into coarse powder and fine powder by the centrifugal force acting on each particle, and the coarse powder rotating around the outer periphery in the classification chamber 28 is discharged from the coarse powder discharge port 38.
It is discharged from the lower hopper 32 and supplied to the crushed material supply pipe 19. The fine powder moving to the center along the upper inclined surface of the classification plate 29 is discharged to the fine powder collection means 33 by the fine powder discharge pipe 30 and then introduced into the second classification means.

Since the air flowing into the classifying chamber 28 together with the powder material flows in a swirling flow, the velocity of the particles swirling in the classifying chamber 28 toward the center becomes relatively smaller than the centrifugal force. In the chamber 28, particles having a small particle diameter are satisfactorily classified, and fine powder having a very small particle diameter can be efficiently discharged to the fine powder discharge pipe 30. In addition, since the powder material flows into the classifying chamber at a substantially uniform concentration, it can be obtained as a finely distributed powder.

The raw material for pulverization is obtained by an appropriate introducing means 35.
The pulverized material introduced into the supply pipe 24 and finally obtained is taken out of the system from the fine powder discharge pipe 30 through a fine powder collector such as a cyclone or a bag filter.

By using the airflow classifier shown in FIG. 10 in combination with the impingement airflow pulverizer, the mixing of fine powder into the pulverizer is suppressed or prevented well, and the overpulverization of the pulverized material is prevented. In addition, the classified coarse powder is smoothly supplied to the crusher, further uniformly dispersed in the accelerating tube, and satisfactorily crushed in the crushing chamber, so that the yield of the crushed material and the energy efficiency per unit weight can be increased. it can.

As means for providing the multi-divided classification area as the second classification means, for example, FIG. 12 (cross-sectional view) and FIG.
A multi-segment classifier of the type shown in (solid view) can be exemplified as one of the specific examples. 12 and 13, the side wall is 1
The lower wall has a shape indicated by 125, and the side wall 123 and the lower wall 125 are provided with knife edge type classification edges 117, 118, respectively. According to 118, 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. The classifying chamber upper wall 127 is provided with a knife-edge type inlet edge 119 in the lower direction of the classifying chamber, and further, at the upper part of the classifying chamber, there are provided air inlet pipes 114 and 115 opening to the classifying chamber. Inlet pipe 11
4, 115, a first gas introduction adjusting means 12 such as a damper;
0, second gas introduction adjusting means 121 and static pressure gauge 128, 1
29 are provided. The positions of the classification edges 117 and 118 and the inlet edge 119 differ depending on the type of fine powder and the desired particle size. The outlets 111, 112, and 11 that open into the room are provided on the bottom of the classifying chamber so as to correspond to the respective dividing areas.
3 is provided. The outlets 111, 112, 113
Opening / closing means such as valve means may be provided.

The fine powder supply nozzle 116 comprises a right-angled cylindrical portion and a pyramid-shaped cylindrical portion. When the ratio of the inner diameter of the right-angled cylindrical portion to the inner diameter of the narrowest portion of the pyramid-shaped cylindrical portion 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. Outlet 11
The pressure in the classification area is reduced through at least one of 1, 112, and 113, and the fine powder is reduced at a flow rate of 50 to 300 m / sec by a gas flow flowing through the raw material supply nozzle 116 opened in the classification area by the reduced pressure. The gas is supplied to the classification area via the supply nozzle 116.

When the fine powder is supplied to the classification area at a flow rate of less than 50 m / sec, it is difficult to sufficiently disperse 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, so that the classification yield tends to decrease.

The supplied fine powder moves along a curved line 130 due to 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, large particles (coarse powder) are classified outside the airflow (that is, the first fractionation area on the left side of the classification edge 118), and medium powder (particles having a particle size 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 size equal to or less than the specified particle size) is classified into the classification edge 1
17 is classified into a third fractionation area on the right side. The classified coarse powder is discharged from an outlet 111, and the medium powder is discharged from an outlet 112.
And the fine powder is discharged from the discharge port 113.

For the introduction of fine powder into the classification area, a method of sucking and introducing using the suction force of a cyclone; air supply means such as injection is provided in the fine powder supply nozzle, and the suction force and the injection force from the cyclone are used. And compressed air. An introduction method using an air conveying means such as suction introduction or injection is preferable because the sealing performance of the apparatus system is not required as compared with pressure introduction. FIG. 3 shows an example of an apparatus in which the injection 147 is attached to the fine powder supply nozzle. Examples of the multi-segment classifier, which is the second classifier, include a classifier having a Coanda block, such as Nippon Steel Mining's Elbow Jet, and utilizing the Coanda effect.

Since the size of the classification area of the multi-segmentation classifier 101 is usually [10 to 50 cm] × [10 to 50 cm], three or more types of fine powder can be instantly obtained within 0.1 to 0.01 seconds. It can be classified into particles. When the multi-segment classifier 101 is divided into three fractions, the multi-segment classifier 101 converts the fine powder into coarse powder (particles having a specified particle size or more), medium powder (particles having a specified particle size), and fine powder. It is divided into bodies (particles having a specified particle size or less).
Thereafter, the coarse powder is returned to the pulverizer 108 through the discharge conduit 111 via the collection cyclone 106.

The coarse powder is supplied to the first classifier 109 or the first classifier 109.
It may return to the metering device 102. In order to reduce the load on the first classifier 109 and reliably perform pulverization by the pulverizer 108, it is more preferable to return the coarse powder directly to the pulverizer 108.

The intermediate powder is discharged out of the system via a discharge conduit 112, collected by the collection cyclone 105, and collected by the toner product 1.
Collected as much as possible. The fine powder is discharged from the discharge conduit 113.
And collected by the collection cyclone 104, and then collected as a fine powder 141 having an irregular particle size. The collection cyclones 104, 105, and 106 also function as suction decompression means for sucking and introducing fine powder into the classification area via the nozzle 116.

In the present invention, the pulverizing step shown in the flowchart of FIG. 1 is not limited to this.
For example, the number of the first classifying means may be two for one pulverizing means, or the number of the pulverizing means and the first classifying means may be two or more. What kind of combination constitutes the pulverizing step may be appropriately set depending on a desired particle diameter, 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 shapes shown in FIGS. 12 and 13, but is most suitable for 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 is necessary is just to adopt the thing of a suitable shape.

The raw material to be introduced into the first classifying means is 2 m
m or less, preferably 1 mm or less. A material obtained by introducing the pulverized raw material into the medium pulverization step and pulverizing to about 10 to 100 μm may be used as the raw material in the present invention.

In the conventional pulverization-classification method using a classifier for removing only fine particles as the second classification means, in the particle size of the powder at the end of the pulverization, the coarse particles having a certain particle size or more are completely removed. Required to be removed. Therefore, in the pulverizing step, an unnecessarily high pulverizing capacity is required, and as a result, excessive pulverization is caused, and the pulverization efficiency is reduced.

This phenomenon becomes more conspicuous as the particle size of the powder becomes smaller. In particular, when a medium powder having a weight average particle size of 3 to 10 μm is obtained, the efficiency is significantly reduced.

In the method of the present invention, coarse powder particles and fine powder particles are simultaneously removed by the multi-division classification means. Therefore, even if coarse particles having a certain particle size or more are contained in a certain ratio in the particle size of the powder at the end of the pulverization, the particles are removed well by the multi-division classification means in the next step, so that the restriction in the pulverization step is limited. And the capacity of the pulverizer can be maximized, the pulverization efficiency is improved, and there is less tendency to cause over-pulverization.

Therefore, the fine powder can be removed very efficiently, and the classification yield can be improved satisfactorily.

In the conventional classification method for classifying medium powder and fine powder, agglomeration of fine particles which causes fogging of a developed image is liable to occur due to a long residence time at the time of classification.
When aggregates are formed, it is generally difficult to remove the aggregates from the medium powder. However, according to the method of the present invention, even if the aggregates are mixed into the pulverized material, the aggregates may cause the Coanda effect and / or high-speed movement. Agglomerates are crushed by the accompanying impact and are removed as fine powder, and even if there are aggregates that have escaped crushing, they can be simultaneously removed to the coarse powder area, making it possible to remove aggregates efficiently. .

The manufacturing method and the manufacturing apparatus of the present invention described in detail above can be preferably used for generating 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, if necessary, are mixed with a Hensiel mixer. Alternatively, a pigment or dye is mixed in a resin such as a hot roll, a kneader, a hot kneader such as an extruder, and then melted, kneaded and kneaded to make the resins compatible with each other. The toner can be obtained by dispersing or dissolving, solidifying by cooling, pulverizing and classifying.

In the pulverizing step and the classifying step, the production method and apparatus of the present invention can be used.

Next, the constituent materials of the toner will be described.

When a heating and pressing fixing device or a heating and pressing roller fixing device having an oil applying device is used as the binder resin used for the toner, the following binder resins for toner can be used. is there.

For example, homopolymers of styrene such as polystyrene, poly-p-chlorostyrene and polyvinyltoluene and their substituted products; 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 copolymer; polyvinyl chloride, phenolic resin, natural 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 resin, coumarone indene resin, petroleum resin 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 thermal energy tend to block or cake during storage or in a developing unit, and these problems must also be considered at the same time. In these phenomena, the physical properties of the binder resin in the toner are most significantly involved, but according to the study of the present inventors, when the content of the magnetic substance in the toner is reduced,
At the time of fixing, the adhesion of the toner to the toner image support is improved, but offset tends to occur, and blocking or caking tends to occur. Therefore, in the present invention, 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 binders include crosslinked styrenic copolymers or crosslinked 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.
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 heavy bond or a substituted product thereof;
For example, dicarboxylic acids having a double bond such as maleic acid, butyl maleate, methyl maleate, dimethyl maleate and the like, and substituted products thereof; vinyl esters such as vinyl chloride, vinyl acetate and vinyl benzoate;
Ethylene olefins such as elene, propylene, butylene and the like: 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; Are used alone or in combination of two or more.

Here, as the crosslinking agent, compounds having two or more polymerizable double bonds are mainly used, for example, aromatic divinyl compounds such as divinylbenzene, divinylnaphthalene, etc .; ethylene glycol diacrylate, ethylene glycol 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 the pressure fixing method or the light heat pressure fixing method is used, a binder resin for a pressure fixing toner can be used. For example, polyethylene, polypropylene, polymethylene, polyurethane elastomer, ethylene-ethyl acrylate Copolymer, ethylene-vinyl acetate copolymer, ionomer resin, styrene-butadiene copolymer, styrene-isoprene copolymer, linear saturated polyester, paraffin, and the like.

It is preferable that a charge control agent is mixed (internally added) to the toner particles for use in the toner. The charge control agent makes it possible to control the optimal charge amount according to the development system. In particular, in the present invention, it is possible to further stabilize the balance between the particle size distribution and the charge, and by using the charge control agent The function separation and the complementarity for higher image quality for each particle size range described above can be further clarified. As the positive charge control agent,
Modified products of nigrosine and fatty acid metal salts; quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetrabutylammonium and tetrafluoroborate; used alone or in combination of two or more. Can be. Among these, charge control agents such as nigrosine compounds and quaternary ammonium salts are particularly preferably used.

Also, the general formula

[0088]

[Formula]

A monomer homopolymer represented by the following formula: 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 these cases, these charge control agents also have an action as (all or part of) the binder resin.

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

The above-mentioned charge control agent (having no function 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, the magnetic material contained in the magnetic toner may be iron oxide such as magnetite, γ-iron oxide, ferrite, iron-rich ferrite;
Metals such as iron, cobalt, nickel or these metals and aluminum, cobalt, copper, lead, magnesium, tin, zinc, antimony, beryllium, bismuth,
Cadmium, calcium, manganese, selenium, titanium,
Alloys with metals such as tungsten and vanadium, and mixtures thereof, and the like can be given.

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 thereof 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, and 12 parts by weight to improve the transparency of the OHP film on which the toner image is fixed. The amount is preferably not more than 0.5 parts by weight, more preferably 0.5 to 9 parts by weight.

[0096]

The present invention will be described in detail below with reference to examples.

Example 1 100 parts by weight of styrene-butyl acrylate-divinylbenzene copolymer (polymerization ratio 77: 22: 1, Mw = 2.2 × 10 ⁵ ) 80 parts by weight of magnetite ⁵ parts by weight of low molecular weight polyethylene Nigrosine dye 3 parts by weight The above formulation was mixed with 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-45 type, Ikegai Iron Works Co., Ltd.) set at a temperature of 150 ° C. The obtained kneaded material was cooled and coarsely pulverized with a hammer mill to 1 mm or less to obtain a coarsely crushed material for toner production.

The obtained toner pulverized raw material was pulverized and classified by an apparatus system shown in FIG. The impingement type air current pulverizer uses an apparatus having the structure shown in FIG. 4 and has a tilt in the major axis direction of the accelerating tube with respect to the vertical line (hereinafter referred to as the accelerating tube tilt) of about 0.
° (ie, set up substantially vertically),
The impact surface has a cone shape with an apex angle of 160 ° and an outer diameter (diameter) of 100
Using those mm, the shortest distance L ₂ between the outermost end portion of the collision surface of the collision member that faces the accelerating tube outlet face intersecting the acceleration tube central axis perpendicular is 50 mm, inner diameter 150mm cylindrical grinding chamber Was used. Therefore, the shortest distance L ₁ is 25m
m.

Further, the opening ratio of the supply port of the material to be ground was set to 20% with respect to the area of the accelerating tube at the portion having the supply port.

As the first classifier, a classifier having the structure shown in FIG. 10 was used. The pulverized raw material is supplied to the airflow classifier through the supply pipe 6 by the injection feeder at a rate of 35.0 Kg / hr by the table type first constant-quantity feeder 35, and the classified coarse powder is coarse powder discharge hopper. After being pulverized using compressed air supplied at a pressure of 6.0 Kg / cm ² and 6.0 m ³ / min through the supply pipe 6 of the impingement-type air-flow pulverizer through the feed pipe 32, the raw material is introduced. While being mixed with the toner pulverizing raw material supplied in the section, it is circulated again to the airflow classifier to perform closed circuit pulverization, and the classified fine powder is captured by the cyclone 33 while being entrained by the suction air from the exhaust fan. And collected and introduced into the second metering device 110. At this time, the weight average diameter of the fine powder was 9.1 μm, and 16.0 μm.
m had a sharp particle size distribution substantially not contained.

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.

That is, a Coulter counter TA-II type (manufactured by Coulter) was used as a measuring device, and an interface (manufactured by Nikkaki) for outputting a number distribution and a volume distribution and a CX-1 personal computer (manufactured by Canon) were connected. The electrolyte is 1 grade using primary sodium chloride.
% NaCl aqueous solution is prepared. As a measuring method, a surfactant, preferably an alkylbenzene sulfonate, is used as a dispersant in 100 to 150 ml of the electrolytic aqueous solution.
Add 5 ml, and then add 2-20 mg of the measurement sample. 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 from the particle size distribution.

The obtained fine powder is supplied to a second
In order to classify into three types of coarse powder, medium powder and fine powder by using the Coanda effect at a rate of 45.0 kg / hr through the vibration feeder 103 and the nozzle 116, FIG.
It was introduced into the multi-segmentation classifier 101 shown in FIGS. Elbow Jet EJ-15-III as a multi-segment classification device
A model machine (manufactured by Nippon Steel Mining) was used.

At the time of introduction, the outlets 111, 112,
Collection cyclones 104, 105,
A suction force derived from the pressure reduction in the system due to the suction pressure reduction of 106 and the compressed air from the injection attached to the raw material supply nozzle 116 were used. The fine powder introduced is 0.0
After being classified instantaneously for 1 second or less, the classified coarse powder is collected by a collection cyclone 106, and then is subjected to a collision-type airflow pulverizer 108.
Was introduced again.

The classified medium powder had a weight average particle size of 8.2.
μm (contains 0.9% by weight of particles having a particle size of 4.0 μm or less and 1.0% by weight of particles having a particle size of 12.7 μm or more), and is excellent for toner use. It has excellent performance. At this time, the ratio of the finally obtained medium powder to the total amount of the pulverized raw materials charged (that is,
Classification yield) was 88%. In addition, when the obtained intermediate powder was observed with an electron microscope, it was found that 4 μm
Substantially no such aggregates were found.

0.7% by weight of colloidal silica treated with amino silicone oil was externally added to and mixed with the classified product to prepare a toner sample. Using this toner, a copy test was performed with a Canon NP copying machine. A 100,000-sheet continuous image endurance test was conducted in a normal environment of 23 ° C. and 65% RH. As a result, the image density of the first 100 sheets was 1.40 (by a MABETH reflection densitometer). Is 1.40 ±
It was within the range of 0.05, and the decrease in density due to toner replenishment when the toner replenishing device struck was within 0.05, so that the image was hardly affected. No defective cleaning, drum fusion, filming, etc. occurred during the durability.

Example 2 Using the same raw material for toner pulverization as in Example 1, pulverization and classification were carried out in the same apparatus system. The impingement airflow crusher is
An apparatus similar to that of Example 1 was used except that the configuration shown in FIG. 4 was used and the inclination of the acceleration tube was 10 °. The first classifier and the multi-segment classifier were the same as those used in Example 1. The pulverized raw material was supplied at a rate of 33.0 kg / hr to obtain a fine powder having a weight average diameter of 9.0 μm.
g / hr, and introduced into a multi-segmentation classifier, where the weight average particle size was 8.3 μm (particles having a particle size of 4.0
Containing 1.1% by weight of particles having a particle size of 12.7 μm or more).
Obtained at 6%.

A copy test was carried out using toner externally added and mixed in the same manner as in Example 1. As a result, no problems such as a decrease in density, poor cleaning, fusing of the drum, and filming did not occur throughout the durability test.

Example 3 Using the same raw material for toner pulverization as in Example 1, pulverization and classification were carried out in the same apparatus system. The impingement airflow crusher is
Using the configuration shown in FIG. 4, the inclination of the acceleration tube was set to 2 °,
The same apparatus as in Example 1 was used, except that the supply rate of the material to be ground was 25% with respect to the area of the accelerating tube at the portion having the supply port. Further, as the first classifier and the multi-segment classifier, the same devices as in Example 1 were used. 39Kg / h of ground material
r to obtain a fine powder having a weight average diameter of 9.1 μm,
The fine powder was introduced into a multi-segmentation classifier at a rate of 46.0 kg / hr, and had a weight average diameter of 8.3 μm (containing 0.8% by weight of particles having a particle diameter of 4.0 μm or less, and a particle diameter of 12.7 μm or more. (Containing 1.1% by weight of particles) was obtained with a classification yield of 87%.

A copy test was carried out using toner externally added and mixed in the same manner as in Example 1. As a result, no problems such as a decrease in density, defective cleaning, fusing of the drum, and filming did not occur throughout the durability test.

Example 4 Using the same toner pulverization raw material as in Example 1, pulverization and classification were carried out in the same apparatus system. The impingement airflow crusher is
Example 1 was the same as Example 1 except that the accelerating tube inclination was set to 20 °, and the crushed object supply port was set to an opening ratio of 25% with respect to the area of the accelerating tube having the supply port. A similar device was used. The first classifier and the multi-segment classifier used were the same as those used in Example 1. 30 kg /
hr to obtain a fine powder having a weight average diameter of 9.0 μm,
This fine powder was introduced into a multi-segmentation classifier at a rate of 45.0 kg / hr, and had a weight average diameter of 8.3 μm (containing 0.9% by weight of particles having a particle size of 4.0 μm or less, and a particle size of 12.7 μm or more. (Containing 1.0% by weight of particles) having a sharp distribution of 88% with a classification yield of 88%.

A copy test was carried out using toner externally added and mixed in the same manner as in Example 1. As a result, no problems such as a decrease in density, poor cleaning, fusion of the drum, and filming did not occur throughout the durability test.

Comparative Example 1 Using the same toner pulverization raw material as in Example 1, pulverization and classification were performed according to the flowchart of FIG. The pressure of 6.0 kg / cm ² shown in FIG.
Using compressed air of 6.0 m ³ / min,
As a first classifying unit and a second classifying unit, a dispersion separator DS5UR (manufactured by Nippon Pneumatic Industries, Ltd.) was used. The pulverized raw material is supplied at a rate of 15.0 kg / hr to obtain fine powder having a weight average diameter of 7.9 μm, and the fine powder is supplied at a rate of 15.0 kg / hr as DS which is a second classifying means.
5UR and a weight average diameter of 8.4 μm (particle diameter of 4.0 μm).
2.0% by weight of particles having a particle size of 12.7 μm or less.
A medium powder having a rather broad particle size distribution (containing 3.2% by weight of the above particles) was obtained at a classification rate of 67%.

Comparative Example 2 Using the same toner pulverizing raw material as in Example 1, pulverization and classification were performed in the same manner as in Comparative Example 1. The crushing machine shown in FIG. 16 was used as the collision-type airflow crushing machine, and the collision member used was a conical shape having a vertex angle of 160 ° at the collision surface. The raw material is 20.0K
g / hr into DS5UR, which is the second classifying means, and weighs 8.4 μm (2.0% by weight of particles having a particle size of 4.0 μm or less and particles having a particle size of 12.7 μm or more. (Containing 3.2% by weight) having a broad particle size distribution with a classification yield of 68%.

[0115]

According to the present invention, a toner having a sharp particle size distribution can be obtained with a high pulverization efficiency and a high classification yield, as compared with the conventional pulverization-classification method for producing a toner. There is an advantage that the occurrence of coarse particles is prevented, the device-like abrasion due to the toner component is prevented, and continuous and stable production can be performed.

Further, by using the toner manufacturing method and apparatus system of the present invention, an excellent predetermined image density and stability, good durability, and free from image defects such as fog and poor cleaning can be obtained as compared with the conventional method. The toner for developing an electrostatic charge image having the particle size described above can be obtained at low cost. Further, there is an advantage that a toner for developing an electrostatic charge image having a small particle diameter (particularly, 3 to 10 μm) can be effectively obtained.

[Brief description of the drawings]

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

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

FIG. 3 is a schematic diagram showing a specific example of an apparatus system for performing the manufacturing method of the present invention.

FIG. 4 is a schematic cross-sectional view of a pulverizing apparatus showing a specific example for implementing the collision type air pulverizing means of the present invention.

FIG. 5 is an enlarged view of a grinding chamber in FIG.

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

FIG. 7 is a sectional view taken along line B-B 'in FIG.

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

FIG. 9 is a sectional view taken along line D-D 'in FIG.

FIG. 10 is a schematic sectional view of a preferred embodiment of a first classification means used in the production method and apparatus of the present invention.

11 is a sectional view taken along the line F-F 'of FIG.

FIG. 12 is a cross-sectional view of a classifier that is a specific example for implementing the multi-segment classifier of the present invention.

FIG. 13 is a three-dimensional view of a classification device as a specific example for implementing the multi-division classification means of the present invention.

FIG. 14 is a plan view of a conical collision member having a projection in the center.

FIG. 15 is a flowchart for explaining a conventional manufacturing method.

FIG. 16 is a schematic sectional view of a conventional collision-type airflow pulverizer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Acceleration pipe 2 High-pressure gas chamber 3 High-pressure gas ejection nozzle 4 Collision member 5 Pulverization chamber 6 Pulverized material discharge port 7 High-pressure gas supply port 8 High-pressure gas introduction pipe 9 Throat part 10 Pulverized material supply port 11 Acceleration pipe outlet 12 Secondary gas Inlet 14 Side wall 15 Edge end 16 Collision surface 17 Front wall 18 Collision member support 19 Pulverized material supply pipe 24 Powder supply pipe 25 Upper cover 26 Guide chamber 27 Introduced louver 28 Classification chamber 29 Classification plate 30 Fine powder discharge pipe 31 Lower casing 32 Hopper for discharging coarse powder 35 Raw material introduction means for pulverization 36 Main casing 37 Classification louver 38 Coarse powder discharge port 80 Pulverized material 81 Fine powder discharge port

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G03G 9/08-9/097 B02C 19/06

Claims (11)

(57) [Claims] 1. A mixture containing at least a binder resin and a colorant is melt-kneaded, the kneaded product is cooled, and the cooled product is pulverized by a pulverizing means to obtain a pulverized product. Means to classify into coarse powder and fine powder, the classified coarse powder is finely pulverized by an impingement airflow pulverizing means to produce fine powder, and the fine powder is circulated to the first classifying means and classified. In a method of producing a toner for developing an electrostatic image from a powder having a predetermined particle size range obtained by introducing the fine powder into a second classifying means and classifying, the impinging airflow pulverizing means an acceleration tube for the coarse particles conveyed by a high-pressure gas accelerated, the coarse powder and a grinding chamber for pulverizing; the pressurized-speed tube, the accelerating tube throat
Parts and have a grinding object supply port for supplying the object to be crushed to the pressurized-speed tube into the accelerating tube side wall between the accelerating tube outlet,該被pulverized product in the sidewall portions with該被pulverized feed opening The opening ratio of the supply port is at least 20 % with respect to the area of the accelerating tube at the accelerating tube portion having the supply port for the material to be pulverized; provided inside the pulverizing chamber so as to face the opening of the outlet of the accelerating tube. A crushing member having a colliding surface is provided; the grinding chamber has a side wall for further crushing the crushed material of the coarse powder crushed by the colliding member by collision, and the side wall and an edge of the colliding member; Closest distance L of
₁ is shorter than the closest distance L ₂ between the grinding chamber front wall facing the impact surface and the edge of the collision member, in the pulverizing chamber, pulverization of coarse powder in the collision surface and the side wall of the impact member After further pulverizing the pulverized material of the coarse powder, the fine powder is circulated to the first classifying means, and the fine powder classified by the first classifying means is multiplied by at least three which is the second classifying means. Introduced into the divided classification area, the particle group is lowered in a curved line due to the Coanda effect, and the coarse powder mainly composed of the particle group having a predetermined particle size or more is divided and collected in the first fractionation area. Divided collection of medium powder mainly composed of particles of a predetermined particle size range in the image area, and divided collection of fine powder mainly composed of particles of less than a predetermined particle diameter in the third fractionation area, Circulating the classified coarse powder to the pulverizing means or the first classifying means. . 2. The method for producing a toner according to claim 1, wherein the accelerating tube is installed such that the inclination of the accelerating tube in the major axis direction is 0 to 45 ° with respect to a vertical line. 3. The method for producing a toner according to claim 1, wherein the accelerating tube is installed such that the inclination of the accelerating tube in the major axis direction is 0 to 20 ° with respect to a vertical line. 4. The method for producing a toner according to claim 1, wherein the accelerating tube is installed such that the inclination of the accelerating tube in the major axis direction is 0 to 5 ° with respect to a vertical line. 5. A first classifying means for classifying a finely pulverized product, a pulverizing means for pulverizing a coarse powder classified by the first classifying means, and a first classifying method for the powder pulverized by the pulverizing means. Introduction means for introducing into the means, the fine powder classified by the first classification means at least coarse powder by Coanda effect,
Multi-divided classifying means as a second classifying means for classifying into medium powder and fine powder, and supply for supplying coarse powder classified by the multi-divided classifying means to the pulverizing means or the first classifying means Wherein the crushing means has an accelerating tube for conveying and accelerating the supplied coarse powder with a high-pressure gas, and a crushing chamber for finely crushing the coarse powder; The tubes are the accelerating tube throat and the accelerating tube
Accelerating tube side wall portion of the grinding object have a grinding object supply opening for supplying to the pressurized speed tract,該被pulverized material supply port in the accelerating tube side wall portion with a該被pulverized feed opening between the outlet Has an opening ratio of at least 20 % with respect to the area of the accelerating tube at the portion having the supply port for the object to be pulverized; A crushing chamber having side walls for further crushing the coarse powder crushed by the collision member by collision, and a closest distance L between the side wall and an edge of the collision member. _1, the toner manufacturing apparatus characterized by shorter than the closest distance L ₂ between the grinding chamber front wall facing the impact surface and the edge of the collision member. 6. The apparatus for producing a toner according to claim 5, wherein the accelerating tube is installed such that the inclination of the accelerating tube in the major axis direction is 0 to 45 ° with respect to a vertical line. 7. The apparatus for producing a toner according to claim 5, wherein the acceleration tube is installed such that the inclination of the acceleration tube in the major axis direction is 0 to 20 ° with respect to a vertical line. 8. The toner manufacturing apparatus according to claim 5, wherein the acceleration tube is installed such that the inclination of the acceleration tube in the major axis direction is 0 to 5 ° with respect to a vertical line. 9. The toner manufacturing apparatus according to claim 5, wherein the classified coarse powder is stored in a coarse powder discharge hopper and then supplied to a fine pulverizing means. 10. The toner manufacturing apparatus according to claim 5, wherein a pulverized material discharge port for discharging the pulverized material to be pulverized is provided behind the collision surface of the collision member. 11. The apparatus for producing a toner according to claim 5, further comprising a communicating means for circulating the pulverized powder pulverized by the collision type air current pulverizing means to the air current classifying means.