JPH1090934A - Manufacture of toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the manufacturing method of a toner by which a small-grain toner for developing electrostatically charged images having a fine grain distribution not including agglomerates and superfines can be efficiently manufactured. SOLUTION: In a toner manufacturing method, after fine particle raw materials consisting of coarse crushed materials are introduced into a specific impact type air-flow crusher for being finely crushed, they are introduced into a first classifying process that has a sloped classifying plate which has been arranged to the bottom part of a classification chamber and whose central part is raised, and has a classification louver for causing swirling flow inside the classification chamber, and also that has a classification means for classifying the fine particles so that they are centrifugally separated by the swirling air flow introduced into the classification chamber through the classification louver; and the particles are classified into first coarse particles and first fine particles, and the first fine particles are removed, and the first coarse particles are inroduced into a second classification process for classifying them into second coarse particles and second fine particles, and the second coarse particles are again crushed by the above crushing means and are circulated, and the second fine particles are taken as the classification product for the toner product.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a toner, and more particularly to a high-quality classified product having a sharp particle size distribution by efficiently pulverizing and classifying solid particles containing a binder resin. The present invention relates to a method for producing a toner for developing an electrostatic image, comprising:

[0002]

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

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

[0004] In addition, in order to obtain toner particles composed of fine particles having a required particle size, a method shown in a flowchart of FIG. 14 has conventionally been generally employed. That is, as shown in FIG. 14, the powder raw material composed of the coarsely pulverized toner is first continuously or sequentially supplied to the first classification means and classified into coarse powder and fine powder. Of the classified items,
Coarse powder mainly composed of a group of coarse particles having a specified particle size or more is sent to a pulverizing means and finely pulverized, then introduced again into a first classifying means and circulated to be classified into a coarse powder and a fine powder. Then, the fine powder arranged in the particle group containing the particles within the specified particle size range and the particles having the specified particle size or smaller is sent to the second classifying means, and the medium powder mainly composed of the particle group having the specified particle size is used. And a fine powder mainly composed of a group of particles having a specified particle size or less (hereinafter, referred to as ultrafine powder). The obtained intermediate powder is used as a classified product for producing a toner.

Various pulverizers are used as the pulverizing means used in the above-mentioned conventional classification / pulverization process. For pulverizing a coarsely pulverized toner mainly composed of a binder resin, a jet airflow as shown in FIG. 15 is used. The jet air flow crusher used, particularly the collision air flow crusher, is used. In such an impingement type air current pulverizer using a high-pressure gas such as a jet air flow, a powder raw material, which is an object to be ground, is transported by a jet air flow, is injected from an outlet of an acceleration tube, and the powder raw material is discharged from an outlet of the acceleration tube. The powder raw material is pulverized by the impact force of a collision with a collision surface of a collision member provided opposite the opening surface of the powder material. For example, in the collision type air flow pulverizer shown in FIG. 15, the collision member 164 is provided so as to face the outlet 163 of the acceleration tube 162 to which the high-pressure gas supply nozzle 161 is connected.
With the high-pressure gas supplied to 62, the powder raw material is sucked into the acceleration pipe 162 from the powder raw material supply port 165 communicating with the acceleration pipe 162, and the powder raw material is ejected together with the high-pressure gas to form the collision member 164. The powder material is caused to collide with the collision surface 166, and the pulverized material is pulverized by the impact force.
7 to discharge.

However, in the collision type air-flow crusher shown in FIG. 15, since the supply port 165 for the crushed object is provided in the middle of the acceleration tube 162, the powder as the crushed object sucked into the acceleration tube 162 is introduced. Immediately after passing through the pulverized material supply port 165, the raw material is dispersed in the high-pressure airflow while changing the flow path toward the acceleration pipe outlet 163 by the high-pressure airflow ejected from the high-pressure gas supply nozzle 161, and is rapidly accelerated. . In this state, relatively coarse particles of the material to be pulverized flow in the lower part of the accelerating tube due to the effect of inertia force, while relatively fine particles flow in the higher part of the accelerating tube. The raw material particles are not sufficiently uniformly dispersed, and the collision member 164 in the pulverizing chamber 168 is separated into a high concentration flow and a low concentration flow.
Partially concentrate on the collision. For this reason, there has been a problem that the pulverization efficiency is apt to be reduced and the processing capacity is apt to be reduced.

Further, the collision surface 166 is located near the
Since a high concentration of dust and dust composed of locally crushed material and crushed crushed material is likely to occur, particularly when the crushed material contains a low-melting substance such as a resin, Fusing, coarsening, agglomeration, and the like of the material to be ground are likely to occur. If the object to be ground has abrasion properties, local powder wear is likely to occur on the collision surface 166 of the collision member 164 and the acceleration tube 162, and the frequency of replacement of the collision member 164 increases. There was a point to be improved from the viewpoint of continuous stable production.

On the other hand, the collision surface 16 of the collision member 164
6 has a conical shape having an apex angle of 110 ° to 175 ° (JP-A-1-254266), or has a projection on a plane where the collision surface intersects perpendicularly with the extension of the central axis of the collision member. A collision plate shape (Japanese Utility Model Laid-Open No. 1-148740) has been proposed. In these pulverizers, since it is possible to suppress a local increase in the dust concentration near the collision surface, it is possible to somewhat reduce the fusion, coarsening, aggregation, and the like of the pulverized material and slightly improve the pulverization efficiency. However, in some cases, further improvement has been desired.

For example, if the weight average particle size is 8 μm and
In order to obtain a toner having a particle size distribution in which particles having a particle size of μm or less are 1% or less by volume%, a pulverizing means such as an impingement airflow pulverizer having a classification mechanism for removing a coarse powder region is used.
After pulverizing the raw material to a predetermined average particle size, the mixture is classified by a classifier to remove coarse powder, and the obtained pulverized product is separated by another classifier as a second classification means to remove ultrafine powder. Thus, a medium powder having a desired particle size distribution is obtained. Here, the weight average particle size is data measured using a Coulter Counter TA-II or Coulter Multisizer II manufactured by Coulter Electronics Co., Ltd. (USA) using an aperture of 100 μm.

[0010] However, a problem with such a conventional method is that the second classifying means for the purpose of only removing the ultrafine powder requires a method of completely removing a coarse particle group having a certain particle size or more. , The load on the pulverizing means must be increased and the amount of processing must be reduced. Furthermore, if it is attempted to completely remove a coarse particle group having a particle size larger than a certain specified particle size, excessive pulverization is apt to occur, and a large amount of ultrafine powder is generated in the pulverization step. As a result, there is a problem that a phenomenon such as a decrease in yield is easily caused in the second classifying means for removing the ultrafine powder in the next step. or,
The second classification means for removing ultrafine powder has a problem that it is difficult to remove aggregates as ultrafine powder when aggregates composed of ultrafine particles are generated. . In this case, the agglomerates are mixed into the final product,
It is difficult to obtain a product with a fine particle size distribution,
Aggregates in the final product collapse in the toner and become extremely fine particles, which is one of the causes of deteriorating image quality.

Conventionally, various airflow classifiers and airflow classifier methods have been proposed for the second classifier for the purpose of removing ultrafine powder as described above. Among them, a rotary blade is used. There are classifiers and classifiers without moving parts. Among them, a classifier without a movable part includes a fixed wall centrifugal classifier and an inertial force classifier. Loffier. F. and K. Maly: Symposium on Powde
An elbow jet classifier, which is exemplified by r Technology D-2 (1981) and commercialized by Nippon Steel Mining,
Okuda.S.and Yasukuni. J.:Proc.Inter.Symposium on
A classifier exemplified by Powder Technology '81, 771 (1981) has been proposed.

Generally, many different properties are required for a toner, and in order to obtain a product satisfying all the required properties, the properties of the toner are determined not only by selection of raw materials to be used but also by a manufacturing method. Often. Because of this,
For example, in the toner classification process, it is required that the toner particles obtained by the classification have a sharp particle size distribution. Further, in the production of toner, it is desired to efficiently and stably produce high quality toner at low cost. Further, in recent years, toner particles to be used have been gradually miniaturized in order to improve image quality in copying machines and printers. In contrast, in general, the function of the interparticle force increases as the material becomes finer, but the same applies to resin particles and toner particles. Difficult problems arise.

In particular, when trying to obtain a toner having a sharp particle size distribution having a weight average particle size of 10 μm or less, there is a problem that the classification yield is reduced by the conventional classification apparatus and classification method. Further, the weight average particle size is 8
When a toner having a sharp particle size distribution of not more than μm is to be obtained, the classification yield is remarkably reduced particularly with the conventional classification apparatus and classification method. Further, even if a desired product comprising fine particles having a fine particle size distribution can be obtained by the conventional method, the process becomes complicated, the classification yield is reduced, the production efficiency is poor, and the cost is high. That is inevitable. This tendency becomes more pronounced as the desired particle size of the product becomes smaller.

JP-A-63-101858 (corresponding to US Pat. No. 4,844,349) discloses a first classifier,
Although a method and apparatus for producing a toner using a pulverizing means and a multi-divided classifying means as a second classifying means following the pulverizing means have been proposed, they cannot be said to be sufficient, and a toner having a weight average particle diameter of 8 μm or less can be more stably and efficiently used. There is a long-felt need for a method and apparatus system for manufacturing.

[0015]

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a method of manufacturing a toner for developing an electrostatic image, which solves the above-mentioned various problems in the prior art. . That is, an object of the present invention is to provide a manufacturing method capable of efficiently manufacturing an electrostatic image developing toner, and to provide a manufacturing method capable of efficiently manufacturing an electrostatic image developing toner having a fine particle size distribution. The purpose is to provide. Further, the present invention is a method of melt-kneading a mixture containing a binder resin, a colorant and an additive, and after cooling the melt-kneaded material, from a powder raw material composed of solid particles formed by coarse pulverization, aggregates and It is an object of the present invention to provide a method capable of efficiently and efficiently producing a particle product (used as a toner) having a fine predetermined particle size distribution that does not contain an ultrafine powder. In particular, an object of the present invention is to provide a toner production method capable of efficiently producing a toner for developing an electrostatic charge image having a small and sharp particle size distribution having a weight average particle diameter of 10 μm or less, and further, 8 μm or less. It is in.

[0016]

The above object is achieved by the present invention described below. That is, the present invention relates to a method comprising melting and kneading a mixture containing at least a binder resin and a colorant, cooling the obtained kneaded material, and then pulverizing the coarsely pulverized product obtained by pulverizing the cooled product by a pulverizing means. First, the body material
Introduced into the classification step to classify the first fine powder and the first coarse powder, then the classified first fine powder is used as a classified product for producing a toner, and the first classified powder is classified in the first classification step. It has an accelerating tube for conveying and accelerating the object to be crushed by a high-pressure gas using the coarse powder as an object to be crushed, and a crushing chamber for finely crushing the object to be crushed. A collision member having a collision surface provided opposite to the surface is provided, and a rear end portion of the acceleration tube has a crushed object supply port for supplying the crushed object into the acceleration tube, and the collision surface is , And a protruding central part where the center protrudes,
A collision-type air flow having a shape consisting of a cone-shaped outer peripheral collision surface provided on the outer periphery thereof and a side wall for further crushing the crushed object crushed by the collision member in the crushing chamber by collision. Introduce it into a pulverizer, pulverize it, and then pulverize the finely pulverized material into the classification chamber with a raised center at the bottom of the classification chamber and a swirl flow in the classification chamber. A louver, and the powder particles are swirled and flown by an air flow flowing into the classification chamber through the classification louver, centrifuged, and introduced into a first classification step of classifying the powder. After classifying the powder into the first fine powder and the first coarse powder, the classified first coarse powder is introduced into the second classifying means of the second classifying step, and further classified into the second coarse powder and the second fine powder. (2) The coarse powder is introduced again into the above-mentioned impingement type air current pulverizer, pulverized and circulated, and the second fine powder is A method for producing a toner which is characterized in that a classified product for producing a toner.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be specifically described below with reference to the accompanying drawings. FIG. 1 is an example of a flowchart showing an outline of the manufacturing method of the present invention. As shown in the flowchart, the production method of the present invention first introduces a powder raw material composed of a predetermined amount of coarsely pulverized material into a specific pulverizing means and pulverizes the material. The powder particles are swirled and flown by the airflow flowing into the classification chamber through the, and are introduced into the first classification step of classifying the powder by centrifugal separation to classify the powder into the first coarse powder and the first fine powder. The first fine powder consisting of fine powder is removed, and the first coarse powder is introduced into the second classifying step to form the second coarse powder and the second coarse powder.
It is characterized in that the second coarse powder is again introduced into the above-mentioned pulverizing means, finely pulverized and circulated, and the classified second fine powder is used as a classified product for a toner product. At this time, the first fine powder (ultrafine powder composed of a group of particles smaller than a specified particle size) classified in the first classification step generally generates a powder raw material that is a coarsely pulverized product composed of a toner material. It is supplied to the melting and kneading process at the time and reused or discarded. The second fine powder (classified product for a toner product) is used as it is as a toner product, or after being mixed with an external additive such as hydrophobic colloidal silica, is made into a toner product.

As described above, the method for producing a toner according to the present invention has a simple process of pulverization and classification.
By controlling the type of equipment used in each step, classification conditions and pulverization conditions, a weight average particle size of 10 μm is obtained.
m, particularly a classified product having a small particle size and a sharp particle size distribution of not more than 8 μm containing no ultrafine powder or aggregates can be efficiently obtained. As a result, efficient production of high quality toner products becomes possible, and toner production costs can be significantly reduced.

FIG. 2 shows an example of an apparatus system to which the method for producing a toner of the present invention is applied, and the present invention will be specifically described based on this. To a powder raw material, which is a toner raw material introduced into the apparatus system, a mixture containing at least a binder resin and a colorant is melt-kneaded, the obtained kneaded material is cooled, and the cooled material is further coarsely crushed by a crushing means. A coarsely crushed product is used. The toner material used at that time will be described later.

In the method for producing a toner according to the present invention, the powdery raw material of the toner comprising the above coarsely pulverized material is first
A predetermined amount is introduced into the crusher 28 by the injection feeder 35 via the first constant-rate feeder 21,
The powder raw material is finely pulverized. Thereafter, the obtained finely pulverized material is introduced into the first classifier 1 through a finely pulverized material discharge pipe, and classified into a first fine powder and a first coarse powder. The first fine powder classified here is collected via the collection cyclone 2.
On the other hand, the classified first coarse powder is introduced into the second classifier 22 and is classified into the second fine powder and the second coarse powder by the second classifier 22. The second coarse powder classified here is again introduced into the pulverizer 28 and circulated. The second fine powder classified by the second classifier 22 is collected by the collection cyclone 23,
This is a classified product 33 for toner production.

In the apparatus system to which the method for producing a toner according to the present invention is applied, as a first classifying means, an inclined classifying plate provided at the bottom of the classifying chamber and having a raised central portion as illustrated in FIG. And a classification louver for causing a swirling flow in the classification chamber, and the powder particles are swirled and flown by an airflow flowing into the classification chamber through the classification louver to centrifugally separate and classify the powder. Use a classifier. Hereinafter, the airflow classifier 1 illustrated in FIG. 3 will be described.

In FIG. 3, reference numeral 14 denotes a tubular main body casing of the airflow classifier 1, and reference numeral 18 denotes a lower casing, and a coarse powder discharge hopper 10 is connected to a lower portion of the lower casing 18. A classifying chamber 7 is formed inside the main casing 14. The classifying chamber 7 has an annular guide chamber 17 attached to the upper part of the classifying chamber 7 and a center provided at the bottom of the classifying chamber 7. A conical (umbrella-shaped) classifying plate 8 having a raised portion is disposed.

A classifying louver 11 arranged in the circumferential direction of the side wall of the guide chamber 17 is provided at a lower portion of the main body casing 14. The classifying louver 11 is turned from the outside to the classifying chamber 7 via the classifying louver 11. It has a structure in which secondary air (classified air) 12 for causing a flow is taken. A coarse powder discharge port 19 is formed around the outer periphery of a conical (umbrella-shaped) classifying plate 8 provided at the bottom of the classifying chamber 7 and having a raised central portion. The chute 9 is connected. The lower end of the fine powder discharge chute 9 is shown in FIG.
As shown in FIG. 3, the end is located outside the side wall of the lower casing 18. Further, although not shown, the tip of the fine powder discharge chute 9 is connected to a suction fan via fine powder collecting means such as a cyclone or a dust collector, and is operated through the fine powder discharge chute 9 by operating the suction fan. Thus, a suction force is applied to the classification chamber 7 so that a swirling flow required for classification is generated by suction air 12 flowing into the classification chamber 7 from between the classification louvers 11.

The air-flow classifier used as the first classifier has the above-described structure. In the example of FIG. 3, a collision-type air-flow pulverizer 28 having a configuration described later is connected to the upper part of the main casing 14. The raw material powder introduced into the pulverizer is finely pulverized into a finely pulverized product, and is sent to the air-flow type classifier of the first classification means to be classified. That is, when the air containing the finely pulverized material is supplied into the guide chamber 17 from the finely pulverized material input port 16, the air including the finely pulverized material passes through the space between the classifying louvers 11 from the guide chamber 17 and passes through the classification chamber 7.
While swirling inside, it flows while being dispersed at a uniform concentration of finely pulverized material. In order to perform the classification with high accuracy, it is necessary to make the flow path until the above-mentioned finely pulverized material reaches the classification chamber 7 in a shape in which the concentration of the finely pulverized material hardly occurs. Therefore, in the present invention, for example, as shown in FIG. 3, in order to improve the dispersion state of the particles, the raw material straightening plate 15 and the finely pulverized material having an enlarged surface area and a shape capable of lowering the dust concentration. It is preferable that the inlet 16 is provided in a flow path until the finely pulverized material reaches the inside of the classification chamber 7.

As described above, the first coarse powder flowing into the classification chamber 7 while being swirled and dispersed is generated by a suction fan (not shown) connected to the fine powder discharge chute 9. The swirling is increased by the suction air 12 flowing from between the classification louvers 11 of the classification chamber. As a result, due to the centrifugal force acting on each particle, the finely pulverized material pulverized by the collision type air flow pulverizer and introduced into the first classification step is the first pulverized material.
It is centrifuged into a coarse powder and a first fine powder (ultra fine powder).

That is, the coarse powder in the finely pulverized material rotates around the outer periphery of the classification chamber 7 by the centrifugal force acting on the coarse powder, is discharged from the coarse powder discharge port 19, and is further discharged from the lower hopper 10.
Is more exhausted. The first coarse powder that has been classified and discharged by the first classification means in this way is introduced into the second classifier 22 in the second classification step. On the other hand, the fine powder (second fine powder) that moves while being swirled to the center along the upper inclined surface of the classification plate 8 by centrifugal force is discharged by the fine powder discharge chute 9.

According to the classifier having the above configuration shown in FIG. 3 used as the first classifying means, the flow path until the finely pulverized material reaches the inside of the classifying chamber 7 has a shape as shown in the figure. A raw material straightening plate 15 having fine particles and a fine pulverized material inlet 16 are provided,
Since the particle stream can be dispersed and fly with the propulsive force from the finely pulverized material input port 16, the dispersion of the finely pulverized material in the classification area can be improved. Classification accuracy is obtained, and an ultrafine powder having a cohesive property (a weight average particle diameter of 2 μm or less) can be reliably excluded from the finely pulverized material. As a result, since these ultrafine powders are not introduced into the subsequent processes, not only can the yield of the final product be prevented from lowering, but also the same dust concentration can be obtained during the classification by the second classification means. Thus, it is possible to achieve better classification accuracy and improve the yield of the product. That is, this makes it possible to efficiently obtain a product (medium powder) having a sharp particle size distribution by the second classification means.

FIG. 2 to which the method for producing a toner of the present invention is applied.
In the apparatus system shown in (1), as the pulverizing means for obtaining the finely pulverized material to be introduced into the first classifying means as described above, for example, a collision type air flow pulverizer of the type exemplified in FIGS. Used. Hereinafter, these will be described. First, in the collision type air flow fine pulverizer shown in FIG.
3 is provided between the inner wall of the accelerating tube throat section 44 and the outer wall of the high-pressure gas ejection nozzle 45.
(It is also a throat part) and is supplied to the acceleration tube 43. The central axis of the high-pressure gas ejection nozzle 45 and the acceleration tube 4
Preferably, the center axis of 3 is substantially coaxial.

On the other hand, the high-pressure gas is introduced from a high-pressure gas supply port 47, passes through a high-pressure gas chamber 48, preferably through a plurality of high-pressure gas introduction pipes 49, and from a high-pressure gas ejection nozzle 45 to an acceleration pipe outlet 50. Spouting while expanding rapidly in the direction. At this time, the acceleration tube throat section 44
Crushed object 42 due to the ejector effect generated near
Is rapidly accelerated while being uniformly mixed with the high-pressure gas in the accelerating tube throat 44 from the crushed object supply port 46 toward the acceleration tube outlet 50 while being entrained by the gas coexisting with the crushed object 42. . Then, it collides against the collision surface 52 of the collision member 51 facing the acceleration tube outlet 50 in a state of a uniform solid-gas mixed flow without unevenness of the dust concentration. The impact force generated at the time of the collision is based on the sufficiently dispersed individual particles (objects to be crushed 4).
Since it is given in 2), very efficient pulverization can be performed.

The pulverized material pulverized on the collision surface 52 of the collision member 51 is further subjected to secondary collision (or tertiary collision) with the side wall 54 of the pulverization chamber 53, and the pulverized material disposed behind the collision member 51 It is discharged from the discharge port 55. Further, in the collision-type airflow pulverizer shown in FIG. 4, if the collision surface 52 of the collision member 51 is a collision surface having a conical projection at the center as shown in FIGS. In this case, the pulverized material is uniformly dispersed, and the high-order collision with the side wall 54 can be efficiently performed. Furthermore, when the pulverized material discharge port 55 is located behind the collision member 51, the pulverized material can be smoothly discharged.

That is, as shown in FIG. 5, by providing a conical central protruding portion having a protruding central portion on the raw material collision surface 52 of the collision member 51, the material to be pulverized ejected from the acceleration tube 43 is provided. The solid-gas mixed flow of the compressed air and the compressed air is first pulverized on the collision surface 52 of the projection surface of the collision member 51, and further secondary-crushed on the conical collision surface 52 ′ provided on the outer periphery thereof. Tertiary grinding is performed on the side wall 54. At this time, the apex angle α formed by the collision surface 52 at the center of the projection surface of the collision member 51
When (°) and the inclination angle β (°) of the outer peripheral collision surface 52 ′ and the central axis of the accelerating tube with respect to the vertical plane satisfy the following relationship, grinding is performed very efficiently. 0 <α <90, β> 0 30 ≦ α + 2β ≦ 90

That is, when α ≧ 90, the central projection surface 5
The reflected flow of the pulverized material primary-pulverized in Step 2 disturbs the flow of the solid-gas mixed flow ejected from the acceleration tube 43. Also, β
When = 0, the outer-peripheral collision surface 52 'is close to a right angle to the solid-gas mixed flow, and the reflected flow at the outer-peripheral collision surface flows toward the solid-gas mixed flow. . Also, β =
At 0, the powder concentration increases on the outer peripheral collision surface, and when a thermoplastic resin powder or a powder containing a thermoplastic resin as a main component is used as a raw material, a fusion product and an agglomerate are generated on the outer peripheral collision surface. easy. When such a fusion product is generated, stable operation of the apparatus becomes difficult. When α and β satisfy α + 2β <30, the impact force of the primary pulverization on the projection surface 52 is weakened, which leads to a reduction in pulverization efficiency, which is not preferable. Also, when α and β are α + 2β <90, the reflected flow on the outer peripheral collision surface 52 ′ flows downstream of the solid-gas mixed flow, so that the impact force of the tertiary pulverization on the pulverization chamber side wall 54 is weakened and the pulverization efficiency is reduced. Causes a drop in

As described above, when α and β satisfy the following relationship, primary, secondary, and tertiary pulverization are efficiently performed, and the pulverization efficiency can be improved. 0 <α <90, β> 0 30 ≦ α + 2β ≦ 90 More preferable values of α and β are as follows. 0 <α <80 5 <β <40

In the present invention, the use of the above-described impingement type airflow pulverizer makes it possible to reduce the impact of the particles on the impingement member as compared with the conventional airflow pulverizer as shown in FIG. Since the number of times of collision can be increased and the collision can be performed more effectively, the pulverization efficiency can be improved, and the generation of fused material on the collision surface or the like during the pulverization can be prevented, and stable operation can be performed. FIG. 6 is an enlarged view of the pulverizing chamber 53 in the impinging airflow pulverizer shown in FIG. In FIG. 6, the closest distance L ₁ between the edge 61 of the collision member 51 and the side wall 54 is set to the distance between the front wall 62 of the grinding chamber facing the collision surfaces 52 and 52 ′ and the edge 61 of the collision member 51. be shorter than the closest distance L _2, in order not to increase the dust concentration of the pulverizing chamber in the vicinity of the accelerating tube outlet 50 is critical.
Furthermore, recently the contact distance L ₁ is shorter than the closest distance L _2, it is possible to efficiently perform the secondary collision of the pulverized material in the side wall 54.

A crusher as shown in FIG. 4 having the inclined collision surfaces 52 and 52 ′ as shown in FIG. 4 has a collision surface 166 having a 90 ° plane with respect to the acceleration tube 162 as shown in FIG. Compared to a conventional crusher having a collision member 164
In the case of pulverizing a resin or a sticky substance, the object to be pulverized is unlikely to be fused, aggregated or coarsened, and can be pulverized at a high dust concentration. In addition, wear is not concentrated locally, so that the life of the apparatus can be extended and stable operation can be performed.

When the inclination of the longitudinal direction of the acceleration tube 43 shown in FIG. 4 is preferably in the range of 0 ° to 45 ° with respect to the vertical direction, the object 42 is It is possible to perform the processing without blocking. When the fluidity of the crushed material 42 is not good, when the crushed material supply pipe 41 has a cone-shaped member as shown in FIG. Crushed material 42
But the inclination of the acceleration tube 43 is set to 0 ° to 20 ° (more preferably 0 ° to 5 °) with respect to the vertical direction.
Within this range, the material to be ground 42 can be smoothly supplied to the acceleration tube 43 without stagnation of the material to be ground at the lower part of the cone-shaped member.

FIG. 7 is a sectional view taken along the line AA 'in FIG. From FIG. 7, it is understood that the object 42 is smoothly supplied to the acceleration tube 43. The front wall 62 at the plane of the acceleration tube outlet 50 that intersects perpendicularly with the extension of the central axis of the acceleration tube 43
The closest distance L ₂ between the collision member 51 and the outermost end 61 of the collision surface 52 of the collision member 51 facing the collision member 51 is the diameter R of the collision member 51.
It is preferable in terms of pulverization efficiency to be in the range of 0.2 to 2.5 times the above, and more preferable in the range of 0.4 to 1.0 time. The distance L in the _two is less than 0.2 times the diameter of the impact member 51, not preferred may have dust concentration of the impact surface 52 near becomes too Also, when it exceeds 2.5 times, the impact force is weakened As a result, the pulverization efficiency tends to decrease, which is not preferable.

The outermost end 61 and the side wall 54 of the collision member 51
The shortest distance L ₁ between is preferably in the range 0.1 times to 2 times the diameter R of the collision member 51. In the distance L ₁ is less than 0.1 times the diameter R of the collision member 51, a large pressure loss during passage of high pressure gas, easy grinding efficiency is lowered, there is a tendency that fluidity of pulverized material does not go smoothly, 2 If the number exceeds twice, the effect of the secondary collision of the material to be ground on the side wall 54 of the grinding chamber is reduced, and the efficiency of the grinding tends to decrease, which is not preferable. More specifically, the length of the acceleration tube 43 is 50 to 5
The diameter R of the collision member 51 is preferably 30 mm to 300 mm.
Furthermore, the collision surfaces 52, 52 'of the collision member 51 and the side wall 54
Is preferably formed of ceramic from the viewpoint of durability.

FIG. 8 is a sectional view taken along the line BB 'in FIG. In FIG. 8, the distribution state of the crushed object in a plane perpendicular to the vertical direction passing through the crushed object supply port 46 is indicated by an acceleration tube 43.
As the inclination of the particles with respect to the vertical direction increases, the distribution state of the flowing particles becomes more biased. For this reason, the inclination of the acceleration tube 43 is most preferably in the range of 0 ° to 5 °. This was confirmed in an experiment using a transparent acrylic resin internal observation acceleration tube as the acceleration tube 43.

FIG. 9 is a sectional view taken along the line CC 'in FIG. In FIG. 9, the object 42 to be ground is a collision member support 91.
And is discharged rearward through the space between the side walls 54. FIG. 10 is a sectional view taken along the line DD ′ in FIG. In FIG.
Although two high-pressure gas introduction pipes 92 are provided, the number of high-pressure gas introduction pipes 92 may be one or three or more depending on the case.

FIG. 11 is a schematic diagram showing another specific example of the collision type air flow pulverizer preferably used in the present invention. In FIG. 11, the same numbers as those in FIG. 4 indicate the same members. In the collision-type airflow pulverizer shown in FIG. 11, the acceleration tube 43 has a long axis inclination of 0 ° to 45 ° with respect to a vertical line.
°, preferably 0 ° to 20 °, more preferably 0 ° to 5 °
The grinding target 42 is supplied to the accelerating tube 43 from a grinding target supply port 46. At this time, the acceleration tube 43
Compressed gas such as compressed air is supplied to the high pressure gas supply port 102.
And the throat section 44 through the high pressure gas chamber 103
The crushed object 42 supplied to the acceleration tube 43 is instantaneously accelerated to have a high speed. The crushed material 42 jetted into the crushing chamber 53 from the acceleration tube outlet 50 at a high speed is applied to the colliding surfaces 52 and 5 of the colliding member 51.
It crushes by colliding with 2 '.

As described above, in the pulverizer shown in FIG.
The crushing efficiency is improved more than before by dispersing the crushed material 42 in 3 and uniformly squirting the crushed material from the acceleration tube outlet 50 to collide with the collision surface 52 of the opposing collision member 51 efficiently. Can be done. Also, the collision surface 5 of the collision member 51
When 2 and 52 ′ have a shape having conical projections on the collision surface as shown in FIGS. 11 and 5, the dispersion after the collision is also good, and the fusion, aggregation, and Coarsening does not occur, it is possible to pulverize at a high dust concentration, and in the abraded material 42, the abrasion generated on the inner wall of the accelerating tube 43 and the collision surface of the collision member 51 is locally generated. It is possible to prolong the service life and achieve stable operation without concentration.

Also, as in the pulverizer shown in FIG.
If the inclination in the long axis direction of 3 is in the range of 0 ° to 45 °, the material to be ground 42 can be processed without being blocked at the material supply port 46, but the fluidity of the material to be ground 42 is not good. Has a tendency to stay in the lower part of the pulverized material supply pipe 41, but if the inclination of the accelerating pipe 43 is in the range of 0 ° to 20 °, more preferably 0 ° to 5 °, the The material to be crushed 42 is smoothly supplied into the acceleration tube 43 without stagnation.

The sectional view taken along the line CC ′ in FIG. 11 is the same as the sectional view taken along the line CC ′ in FIG.
The crushed material is discharged rearward through the space between the collision member support 91 and the side wall 54.

The second method used in the toner production method of the present invention
As the second classification means in the classification step, any means can be used, but preferably, a rotary airflow classifier that classifies by centrifugal force using forced vortex is used. Examples of such a device include a teaplex (ATP) classifier manufactured by Hosokawa Micron Corporation, a micron separator, a Dona Selec classifier manufactured by Nippon Donaldson Co., Ltd., and a turbo classifier classifier manufactured by Nisshin Seifun Co., Ltd. In the present invention, it is preferable to use a rotary airflow classifier having a configuration as shown in FIG. 12 in order to improve the classification accuracy of fine powder and coarse powder. Hereinafter, the rotary airflow classifier shown in FIG. 12 will be described in detail.

In FIG. 12, reference numeral 121 denotes a cylindrical main body casing. A classification chamber 122 is formed inside the main body casing 121, and a guide chamber 123 is provided below the classification chamber 122. The rotary airflow classifier shown in FIG. 12 is of an individual drive type, and generates a forced vortex using centrifugal force in the classification chamber 122 to classify it into coarse powder and fine powder. A classifying rotor 124 is provided in the classifying chamber 122, and the powder raw material 42 and the air fed into the guide chamber 123 are swirled into the classifying chamber 122 by suction from between the classifying rotors 124. The powder raw material 42 is supplied from a raw material input port 125, and air is supplied from an input port 126,
Further, it is taken in together with the powder raw material 42 from the raw material inlet 125. The powder raw material 42 is supplied to the classification chamber 12 together with the incoming air.
It is carried to 2. It should be noted that the guide room 123 passes through the input port 125.
It is preferable to uniformly distribute the air flowing through the inside and the powder material 42 to the respective classification rotors 124 in order to accurately classify the powder. In addition, the flow path to reach the classification rotor 124 needs to have a shape in which concentration is unlikely to occur. However, the position of the inlet 125 is not limited to this.

The classifying rotor 124 is movable, and the distance between the classifying rotors 124 can be arbitrarily adjusted. The speed control of the classifying rotor 124 is performed through a frequency converter 128. Fine powder discharge pipe 129
Is connected to a suction fan 131 via a fine powder collecting means 130 such as a cyclone or a dust collector, and operates the suction fan 131 to apply a suction force to the classification chamber 122.

In the present invention, the rotary airflow classifier 22 preferably used for the second classifier has the above-described structure, but the classifier to be supplied from the raw material inlet 125 into the guide chamber 123 is Since the finely pulverized material finely pulverized by the collision type air current pulverizer as shown in FIG. 4 described above is introduced into the first classification means and is a powder raw material composed of the first coarse powder classified, the pulverization step and The air containing the air used in the first classification process is introduced into the classifier 22 together with the air. The air containing the powder raw material is sucked from between the classification rotors 124 while being dispersed by the suction air from the classification louver 135, and flows into the respective classification rotors 124 from the guide chamber 123. At this time, the powder raw material that has flowed into the classification chamber 122 together with the air is dispersed by the classification rotor 124 that rotates at a high speed, and is subjected to the centrifugal force that acts on each particle by the forced vortex generated in the classification chamber 122 to generate the powder material. 2 Centrifuged into coarse powder and second fine powder. And the 2nd coarse powder in the classification room 122
It passes through a coarse powder discharging hopper 132 connected to the lower part of the main body casing 121 and through a rotary valve 133 to the above-mentioned crushed material supply pipe of the collision type air flow crusher as shown in FIG. 4 or FIG. Supplied and pulverized again.
On the other hand, the second fine powder is discharged to the fine powder collecting means 130 by the fine powder discharge pipe 129, and is classified as toner-produced products.

In the present invention, as shown in FIG. 2, for example, in the second classification step, a rotary airflow classifier having the structure shown in FIG. By using an impinging airflow pulverizer having the structure shown in FIG. 4 or FIG. 11 as the pulverizing means in the process, the mixing of the fine powder into the pulverizer is favorably suppressed or prevented, so that excessive pulverization of the pulverized material is prevented. You. Further, the second coarse powder classified by the second classification means is smoothly supplied to the pulverizer, is uniformly dispersed in the accelerating tube in the pulverizer, and is further finely pulverized in the pulverization chamber. The yield of the pulverized material and the energy efficiency per unit weight can be increased.

In the rotary air classifier as described above, the classification point is determined by the rotation speed of the classification rotor. However, conventionally, the efficiency of the pulverizing means connected to the classification point is not good.
It is difficult to obtain a small diameter toner as a classified product,
Even if it was obtained, it took a lot of effort. However, in the present invention, since a high-impact air-flow crusher having a configuration as shown in FIG. 4 or 11 is used, the performance of the crushing means can be improved, and the obtained finely crushed material can be further improved. Is introduced into the first classifying means for swirling and flowing the powder particles by the airflow flowing into the classifying chamber through the classifying louver as described above, centrifuging the powder particles, and classifying the powder efficiently. And the first fine powder to remove the ultrafine powder (first fine powder) in advance, and then the above-mentioned rotary classifier as the second classifying means, wherein the first coarse powder containing no ultrafine powder is the second classifying means. Because it has been introduced to
In the second classifying step, the toner raw material can be further finely divided and fine classification can be performed in the fine particle region. As a result, a classified product having fine particles and a sharp particle size distribution can be efficiently obtained. Further, when the above-mentioned rotary classifier is used as the second classifying means, there is an advantage that the classification point can be easily changed only by changing the rotation speed of the classification rotor, and the operability is excellent.

In the present invention, the particle size of the powdery raw material comprising the coarsely pulverized material to be introduced into the pulverizing means is set to 2 mm or less, preferably 1 mm or less. Further, the coarsely pulverized product may be further introduced into the medium pulverization step, and pulverized to about 10 to 100 μm may be used as the powder raw material in the present invention.

The purpose of classifying a group of particles having a specified particle size (medium powder) and a group of particles having a particle size smaller than the specified particle size (ultrafine powder) as shown in the flowchart of FIG. In the conventional pulverization / classification method using the classifier of (2) as the second classifying means, the powder raw material introduced into the second classifying means is one in which a coarse particle group having a specified particle size or more is completely removed. Is required. For this purpose, in the particle size of the powder at the end of the fine pulverization by the pulverizer, it is required that a coarse particle group having a specific particle size or more is completely removed, and the pulverizing ability in the pulverizing step is more than necessary. I was demanded to. As a result, excessive pulverization in the pulverization step was caused, and reduction in pulverization efficiency was caused. This phenomenon becomes more conspicuous as the particle size of the desired powder becomes smaller.
When a medium powder of about 0 μm was obtained, the efficiency was significantly reduced. Furthermore, the amount of the ultrafine particles removed in the second classification step is increased, and there is a problem that the classification efficiency is poor.

On the other hand, in the toner production method of the present invention, after the powder raw material is finely pulverized by the pulverizer, the obtained finely pulverized material is introduced into the classification chamber via the classification louver in the first classification step. The powder particles are swirled and flowed by an air flow, centrifuged, and introduced into a classifier for efficiently classifying the powder, and classified into particles (ultrafine powder) having a particle size smaller than a specified particle size and other coarse particles, Since the ultrafine particles are efficiently removed, the ultrafine powder is not introduced into the second classification means. As a result, the second
In the classification step, the particles having the specified particle size (second fine powder) and the particles having the specified particle size or more (second coarse powder) may be classified. Even if coarse particles exceeding a certain specified particle size are contained in a certain ratio, the second classifying means can satisfactorily classify and remove these coarse particle groups. For this reason, restrictions in the pulverization step are reduced, the capacity of the pulverizer can be used to the maximum, the pulverization efficiency is improved, and there is little tendency to cause over-pulverization. For this reason, the amount of the ultrafine powder can be suppressed, and the ultrafine powder can be classified and removed very efficiently in the first classification step. As a result, in the present invention, the classification yield can be improved satisfactorily.

Further, as in the prior art, when a classification method for classifying into a group of particles having a specified particle size (medium powder) and a group of particles having a particle size smaller than the specified particle size (ultrafine powder) is used for the second classification means. Is
Since the residence time at the time of classification is long, aggregates of ultrafine particles which cause fogging of the developed image tend to be generated during this time. When aggregates are formed, it is generally difficult to remove the aggregates from the medium powder. On the other hand, according to the toner manufacturing method of the present invention, even if the agglomerated material is mixed into the powder raw material as the raw material to be classified, the first classifying means rotates the powder particles introduced into the airflow through the classification louver. Agglomerates are broken by the impact of flow and / or high-speed movement, and are thus removed as ultrafine powder. Furthermore, even if there is any aggregate that has escaped crushing, the aggregate can be removed as a second coarse powder by the second classification means, so that the aggregate can be efficiently removed.

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

Hereinafter, the constituent materials of the toner will be described. When a heat and pressure fixing device or a heat and pressure roller fixing device having a device for applying oil is used as the binder resin used for the toner, the following binder resins for toner can be used. That is, 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 Polymer, styrene-
Acrylic ester copolymer, styrene-methacrylic ester copolymer, styrene-α-chloromethacrylic copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer Styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-
Styrene copolymers such as indene copolymers; polyvinyl chloride, phenolic resins, phenolic resins modified with natural resins,
Natural resin modified maleic acid resin, acrylic resin, methacrylic resin, polyvinyl acetate, silicone resin, polyester resin, polyurethane resin, polyamide resin, furan resin, epoxy resin, xylene resin, polyvinyl butyral, terpene resin, cumaroindene resin, petroleum resin Etc. can be used.

In a heat and pressure fixing method or a 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 supporting member is transferred to a roller, The adhesion of the toner to the member is an important issue. 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 member is improved, the offset phenomenon is likely to occur, and blocking or caking is also likely to occur. Therefore, when using a heat and pressure roller fixing method in which almost no oil is applied, selection of a binder resin is more important. Preferred binder resins include crosslinked styrenic copolymers and crosslinked polyesters. As comonomers for the styrene monomer of the styrene copolymer, for example, acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, methacrylic acid Monocarboxylic acid having a double bond such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide or a substituted product thereof; maleic acid, butyl maleate,
Dicarboxylic acids having a double bond such as methyl maleate, dimethyl maleate and the like and substituted products thereof: vinyl chloride,
Vinyl esters such as vinyl acetate and vinyl benzoate; vinyl ketones such as vinyl methyl ketone and vinyl hexyl ketone; vinyl monomers such as vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl isobutyl ether A single body or two or more bodies are used.

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

When the toner is used in a pressure fixing method or a light heating pressure fixing method, a binder resin for a pressure fixing toner can be used. For example, polyethylene, polypropylene, polymethylene, polyurethane elastomer, ethylene- Examples thereof include an ethyl acrylate copolymer, an ethylene-vinyl acetate copolymer, an ionomer resin, a styrene-butadiene copolymer, a styrene-isoprene copolymer, a linear saturated polyester, and paraffin.

It is preferable that a charge control agent is blended (internally added) to the toner particles. The charge control agent makes it possible to control the optimal charge amount according to the development system. In particular, in the present invention, 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.

Examples of the positive charge control agent include denatured products such as nigrosine and fatty acid metal salts; tributylbenzylammonium-1-hydroxy-4-naphthosulfonate;
A quaternary ammonium salt such as tetrabutylammonium tetrafluoroborate can be used alone or in combination of two or more. Among these, charge control agents such as nigrosine compounds and quaternary ammonium salts are particularly preferably used.

Further, the following general formula R ₁ : H, CH ₃ ; R ₂ and R ₃ : a substituted or unsubstituted alkyl group (preferably C ₁ -C ₄ )], or a styrene as described above; Copolymers with polymerizable monomers such as acrylates and methacrylates can be used as positive charge control agents, in which case these charge control agents act as (all or part of) the binder resin. It also has

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 and the like. Among them, an acetylacetone metal complex, a salicylic acid-based metal complex or a salicylic acid-based metal salt is preferable, and a salicylic acid-based metal complex or a salicylic acid-based metal salt is particularly preferable. 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).

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 includes iron oxides such as magnetite, γ-iron oxide, ferrite, and iron-rich ferrite; iron, cobalt,
Metals such as nickel or these metals and metals such as aluminum, cobalt, copper, lead, magnesium, tin, zinc, antimony, beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, vanadium Alloys and mixtures.

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, Hansa 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, based on 100 parts by weight of the binder resin.
Further, in order to improve the light transmittance of the OHP film on which the toner image is fixed, the amount is preferably 12 parts by weight or less, more preferably 0.5 to 9 parts by weight.

As described above, according to the present invention, it is possible to obtain a toner having a sharp particle size distribution from a powdery raw material for producing a toner having a weight average particle size of 10 μm or less,
In particular, a toner having a sharp particle size distribution can be obtained from a powder material having a weight average particle size of 8 μm or less.

[0068]

The present invention will be described in more detail with reference to the following examples. Example 1 100 parts by weight of styrene-butyl acrylate-divinylbenzene copolymer (monomer polymerization weight ratio: 80.0 / 19.0 / 1.0, weight average molecular weight = 350,000) Magnetic iron oxide (average particle size: 0) .18 μm) 100 parts by weight Nigrosine 2 parts by weight Low-molecular-weight ethylene-propylene copolymer 4 parts by weight The above formulation was mixed with a Henschel mixer (FM-75).
After mixing well with a mold and a Mitsui Miike Kakoki Co., Ltd.), the mixture was kneaded with a twin-screw kneader (PCM-30, manufactured by Ikegai Iron Works Co., Ltd.) whose temperature was set to 150 ° C. The obtained kneaded material was cooled and coarsely pulverized to 1 mm or less with a hammer mill to obtain a coarsely pulverized material as a powder raw material for producing a toner.

The toner powder raw material obtained above was finely pulverized and classified by the apparatus system shown in FIG. The collision-type airflow crusher 28 uses an apparatus having the configuration shown in FIG. 4 and has a tilt in the major axis direction of the acceleration tube with respect to the vertical line (hereinafter referred to as the acceleration tube tilt) of about 0 ° (that is, substantially the acceleration tube inclination). The impact member 51 shown in FIG. 6 was used. The collision member 51 has α = 55 °, β = 10 °, and outer diameter (diameter).
The shortest distance L ₂ between the surface of the acceleration tube outlet 50 intersecting at right angles to the central axis of the acceleration tube shown in FIG. 6 and the outermost end 61 of the collision surface 52 of the collision member 51 facing the accelerator tube is used. Is 50 mm, and the shape of the grinding chamber 53 is a cylindrical grinding chamber having an inner diameter of 150 mm. Accordingly, the shortest distance L ₁ between the side walls 54 of the collision member 51 is 25 mm.
As the second classifier 22, a classifier having the configuration shown in FIG. 12 was used. The diameter of the classifying rotor 124 was 200 mm, and the number of revolutions of the classifying rotor was 3000 rpm. p. m. Driven by

In this embodiment, the fine particles are swirled and flown by the airflow flowing through the classification louver 11 having the structure shown in FIG. 3 in the first classification means 1 so that the ultrafine powder and the fine powder are centrifuged. An airflow classifier 1 for separation was used. At this time, the air-flow classifier uses the fine powder discharge chute 9 shown in FIG.
The first fine powder is introduced into the collection cyclone 2 by communicating with the collection cyclone 2 of the apparatus system shown in FIG.
On the other hand, the coarse powder discharge hopper 10 was connected so that the first coarse powder discharged through the coarse powder discharge hopper 10 and the discharge pipe 4 was introduced into the second classifier 22.

The present embodiment will be described in more detail.
The table-type first constant-quantity feeder 21 was used to feed the powdery raw material composed of the coarsely pulverized product at a rate of 30.0 kg / h via an injection feeder 35 through a supply pipe into a collision type having the configuration shown in FIG. It was introduced into an airflow pulverizer 28. The crusher 2
8 is crushed using compressed air having a pressure of 6.0 kg / cm ² (G) and 6.0 Nm ³ / min, and then the resulting finely crushed material is obtained. And FIG.
The fine particles are swirled and flown by the airflow flowing through the classifying louver having the structure shown in FIG. And classified. The ultrafine powder, which is the first fine powder classified by the airflow classifier 1, is collected by the collection cyclone 2, while the first coarse powder is collected by the airflow classifier 22 in the second classification step.
Into the second fine powder and the second fine powder by the classifier 22.
Classified into coarse powder. The classified second coarse powder was again introduced into the pulverizer 28, circulated, and subjected to closed-circuit pulverization. On the other hand, the second fine powder classified by the airflow classifier 22 is collected by the cyclone 23 while being entrained by the suction air from the suction fan 131, and is collected as a classification product 33 for producing toner.

The classified product obtained in this example had a weight average particle size of 6.9 μm, and the particle size of 4.0 μm or less was 2%.
Particles containing 5% by number and having a particle diameter of 10.08 μm or more
It had a sharp particle size distribution containing 3% by volume, and had excellent performance as a classified product for toner. At this time, the ratio of the amount of the finally obtained medium powder to the total amount of the charged powder raw materials (that is, the classification yield) was as high as 82%. When the obtained classified product was observed with an electron microscope, aggregates of 4 μm or more in which ultrafine particles were aggregated were
Substantially not found.

The particle size distribution of the toner can be measured by various methods. In the present invention, the measurement was performed using the following measuring apparatus. That is, a Coulter Counter TA-II type or Coulter Multisizer II (both manufactured by Coulter Inc.) was used as a measuring device. As the electrolyte solution, about 1% NaCl aqueous solution was prepared using primary sodium chloride, and used, for example, ISOTON R-II (manufactured by Coulter Scientific Japan) can be used. As a measuring method, the electrolyte solution 100 to
In 150 ml, 0.1 to 5 ml of a surfactant, preferably alkynebenzenesulfonate, is added as a dispersant, and 2 to 20 mg of a measurement sample is further added. The electrolyte solution in which the sample is suspended is subjected to a dispersion treatment for about 1 to 3 minutes with an ultrasonic disperser,
Using the measuring device, the volume and number of the toner were measured using a 100 μm aperture as the aperture, and the volume distribution and the number distribution were calculated. Then, a weight-based weight average particle diameter determined from the volume distribution according to the present invention was determined.

Example 2 Fine pulverization and classification were carried out in the same apparatus system as shown in FIG. 2 using the same toner powder raw material as in Example 1. That is, the collision-type airflow pulverizer having the structure shown in FIG. 4 is used, and the first classifier is a classifier having the structure shown in FIG.
Pulverization and classification were performed under the same apparatus conditions as in Example 1.
As the second classifying means, a rotary air classifier similar to that shown in FIG. 12 as in Example 1 was used, but the number of revolutions of the classifying rotor was set at 3,400 rpm. In the present embodiment, the powdery raw material is supplied to the above-mentioned apparatus system at a rate of 24.0 kg / h, and contains 32% by number of particles having a weight average particle diameter of 6.1 μm and a particle diameter of 4.0 μm or less. A classified product having a sharp particle size distribution and containing 0.5% by volume of particles having a diameter of 10.08 μm or more was obtained with a classification yield of 75%.

Example 3 Fine pulverization and classification were carried out using the same toner powder raw material as in Example 1 and in the same apparatus system as shown in FIG. That is, the impingement type air current pulverizer having the configuration shown in FIG. 4 was used, and the first classifying means having the configuration shown in FIG. 3 was used, and pulverization and classification were performed under the same apparatus conditions as in Example 1. . or,
As the second classifier, a rotary airflow classifier similar to that of the first embodiment shown in FIG. 12 was used.
The speed was set to 200 rpm. In this embodiment, the powdery raw material is supplied to the above-mentioned apparatus system at a rate of 22.0 kg / h, and contains 15% by number of particles having a weight average particle diameter of 5.7 μm and a particle diameter of 3.17 μm or less. A classified product having a sharp particle size distribution containing 1.0% by volume of particles having a diameter of 8.0 μm or more was obtained with a classification yield of 77%.

Example 4 100 parts by weight of unsaturated polyester resin 4.5 parts by weight of copper phthalocyanine pigment (CI Pigment Blue 15) 4.0 parts by weight of charge control agent (chromium salicylate complex) 4.0 parts by weight The materials were 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-30 type, Ikegai Iron Works Co., Ltd.) set at a temperature of 100 ° C. The obtained kneaded material was cooled and coarsely pulverized to 1 mm or less with a hammer mill to obtain a coarsely pulverized material as a powder raw material for producing a toner. In this embodiment,
In the apparatus system shown in FIG. 2, a collision type air flow pulverizer having a configuration shown in FIG. 4 is used, and an air flow type classifier having a configuration shown in FIG. Grinding and classification were performed under the conditions. In addition, the second classifier has the first embodiment.
A rotary air classifier having the same configuration as that shown in FIG. 12 was used except that the diameter of the classification rotor was 200 mm and the number of revolutions of the classification rotor was 3,500 rpm.

In the present embodiment, the powdery raw material composed of the above coarsely pulverized material is converted into 28.
At a rate of 0 kg / h, it was introduced into the impingement-type airflow pulverizer 28 having the configuration shown in FIG. The powder raw material supplied from the pulverized material supply pipe 41 of the pulverizer 28 is supplied with a pressure of 6.0 kg / cm ² (G) and a pressure of 6.0 kg / cm ² (G).
The pulverized product obtained was pulverized using compressed air of Nm ³ / min, and the obtained finely pulverized product was introduced into the airflow classifier 1 having the configuration shown in FIG. The ultrafine powder, which is the first fine powder classified by the airflow classifier 1, is collected by the collection cyclone 2, and the first coarse powder is introduced into the airflow classifier 22 in the second classification process. And classified into a second fine powder and a second coarse powder. Then, the classified second coarse powder was again introduced into the above-mentioned pulverizer 28 and circulated to perform closed-circuit pulverization. The second fine powder classified by the airflow classifier 22 in the second classification step is
The air is collected by the cyclone 23 while being entrained by the suction air from the exhaust fan 131, and is collected as a classified product 33 for producing toner.

The classified product obtained at this time has a weight average particle size of 6.8 μm, and a particle size of 4.0 μm or less has a particle size of 25 μm.
1.4% particles having a particle size of 10.08 μm or more containing several percent by number.
It had a sharp particle size distribution containing volume%, and had excellent performance as a classified product for toner. At this time,
The ratio of the amount of the finally obtained classified product to the total amount of the charged powder raw materials (that is, the classification yield) was 78%.

Example 5 Fine pulverization and classification were carried out in the same apparatus system using the same toner powder raw material as in Example 4. That is, the impingement type air current pulverizer having the structure shown in FIG. 4 is used, and the first classifier is an air current type classifier having the structure shown in FIG. Was done. As the second classifying means, the same rotary airflow classifier as shown in FIG. 12 was used as in Example 1, but the number of rotations of the classifying rotor was 3,900.
r. p. m. I made it. In this embodiment, the powdery raw material is supplied to the above-mentioned apparatus system at a rate of 26.0 kg / h, and contains 24% by number of particles having a weight average particle diameter of 6.3 μm and a particle diameter of 4.0 μm or less. A classified product having a sharp particle size distribution containing 1.0% by volume of particles having a diameter of 10.08 μm or more was obtained with a classification yield of 79%.

Comparative Example 1 Materials having the same formulation as in Examples 1 to 3 were mixed well with a Henschel mixer (Model FM-75, manufactured by Mitsui Miike Kakoki Co., Ltd.), and then the mixture was mixed at a temperature of 150 ° C. Kneader (PCM
-30 type, manufactured by Ikegai Iron Works Co., Ltd.). The obtained kneaded material was cooled and coarsely pulverized to 1 mm or less with a hammer mill to obtain a coarsely pulverized product for toner production. The obtained toner raw material was pulverized and classified by an apparatus system shown in FIG. However, the crusher shown in FIG. 15 was used for the impingement type air current crusher, and the crusher shown in FIG. 13 was used for the first classifier and the second classifier.
A classifier for centrifuging by the centrifugal force acting on the particles having the structure shown in Table 1 was used.

In the classifier shown in FIG. 13, 201 indicates a cylindrical main body casing, 202 indicates a lower casing, and a hopper 203 for discharging coarse powder is connected to a lower portion thereof. The inside of the main casing 201 is a classification room 2
An annular guide chamber 205 attached to the upper portion of the classifying chamber 204 and a conical (umbrella-shaped) upper cover 206 having a raised central portion are formed.

A plurality of louvers 207 arranged in a circumferential direction is provided on a partition wall between the classifying chamber 204 and the guide chamber 205, and the powder material and the air fed into the guide chamber 205 are separated from each other by the louvers 207. The air is swirled into the classifying chamber 204 from the space. The upper portion of the guide chamber 205 is formed by a space between the conical upper casing 213 and the conical upper cover 206.

A classifying louver 209 arranged in the circumferential direction is provided below the main body casing 201, and classifying air causing a swirling flow from the outside to the classifying chamber 204 is taken in through the classifying louver 209. At the bottom of the classifying chamber 204, a conical (umbrella-shaped) classifying plate 210 whose central portion is high is provided, and a coarse powder discharge port 211 is formed around the outside of the classifying plate 210. A fine powder discharge chute 212 is connected to the center of the classifying plate 210,
The lower end of 12 is bent in an L-shape, and this bent end is positioned outside the side wall of the lower casing 202. Further, the chute 212 is connected to a suction fan via fine powder collecting means such as a cyclone or a dust collector, and applies a suction force to the classifying chamber 204 by the suction fan to classify the chute from between the classifying louvers 209. The swirling flow required for classification is caused by the suction air flowing into the chamber 204.

The air flow classifier used in the present comparative example has the above-described structure. The air supply containing the coarsely pulverized material, which is a powder raw material for toner production, having the above-described configuration is introduced into the guide chamber 205 from the supply tube 208. Is supplied, the air containing the coarsely pulverized material flows from the guide chamber 205 to the classifying chamber 204 while passing between the louvers 207 while flowing at a uniform concentration while being dispersed. The coarsely crushed material that has flowed into the classifying chamber 204 while swirling is further swirled by the suction air flow that flows from between the classifying louvers 209 at the lower part of the classifying chamber generated by the suction fan connected to the fine powder discharge chute 212, The particles are centrifuged into coarse powder and fine powder by the centrifugal force acting on each particle. Then, the coarse powder swirling around the outer periphery in the classification chamber 204 is discharged from the coarse powder discharge port 211 and the lower hopper 203
The fine powder that is discharged by the fine powder and moves to the center along the upper inclined surface of the classification plate 210 is discharged by the fine powder discharge chute 212.

In this comparative example, the powdery raw material composed of coarsely pulverized material was 13.0 kg /
At the rate of h, the mixture is supplied from the injection feeder 35 to the airflow classifier shown in FIG.
The particles were classified by centrifugation by the centrifugal force acting on the particles. The classified coarse powder passes through a coarse powder discharge hopper 203 as shown in FIG.
Is introduced into the pulverizer through the pulverized material supply port 165 of the impingement airflow pulverizer shown in FIG. The coarse powder has a pressure of 6.0 k.
g / cm ² (G), after being pulverized with the pulverizer using compressed air of 6.0 Nm ³ / min, while mixing the pulverized material with the toner pulverized raw material supplied at the raw material introduction unit. ,
The circuit was circulated again through the airflow classifier shown in FIG. 13 to perform closed-circuit pulverization. On the other hand, the fine powder classified by the airflow classifier is collected by the cyclone 30 while being entrained by the suction air from the exhaust fan, and then collected through the quantifier shown in FIG.
Is introduced into the second classifying means having the structure shown in FIG.
Then, a classified product consisting of a group of particles having a prescribed particle size was collected by the cyclone 23.

As a result, 27% by number of particles having a weight average particle diameter of 6.9 μm and a particle diameter of 4.0 μm or less were contained,
A classified product having a particle size distribution containing 1.5% by volume of particles of 0.08 μm or more was obtained with a classification yield of 61%. Thus, both the processing efficiency and the classification efficiency were inferior to those of Examples 1 to 3.

Comparative Example 2 Fine pulverization and classification were performed using the same toner raw materials as in Examples 1 to 3 using the apparatus system shown in FIG. The impact-type air crusher has a conventional structure shown in FIG. 15, and the first classifier and the second classifier have the classifier shown in FIG. And pulverization and classification. As a result, when the powdery raw material was supplied at a rate of 10.0 kg / h, the weight average particle diameter was 6.1 μm.
It contains 33% by number of particles having a particle size of 0 μm or less, and has a particle size of 10.08.
A classified product containing particles having a particle size of 0.5 μm or more and a particle size of μm or more was obtained with a classification yield of 60%. Thus, Examples 1-3
As compared with, both the processing efficiency and the classification yield were inferior.

Comparative Example 3 Materials having the same formulation as in Examples 4 and 5 were mixed well with a Henschel mixer (Model FM-75, manufactured by Mitsui Miike Kakoki Co., Ltd.), and then biaxially set at a temperature of 100 ° C. Kneader (PC
M-30, manufactured by Ikegai Iron Works Co., Ltd.). The obtained kneaded material was cooled and coarsely pulverized to 1 mm or less with a hammer mill to obtain a coarsely pulverized material as a powder raw material for producing a toner.
Using the obtained toner raw material, fine pulverization and classification were performed by an apparatus system shown in FIG. However, a pulverizer having the configuration shown in FIG. 15 was used for the impinging airflow pulverizer, and a classifier having the configuration shown in FIG. 13 was used for the first and second classifiers. Pulverization and classification were performed under the device conditions.

First, the powdery raw material is supplied to the gas flow classifier shown in FIG. 13 through the supply pipe 208 by the injection feeder 35 at the rate of 12.0 kg / h by the first table-type fixed quantity supply device 21. Then, the particles were classified by centrifugation by the centrifugal force acting on the particles. The classified coarse powder is introduced into the pulverizer through the coarse powder discharge hopper 203 from the supply port 165 of the pulverized material of the impingement airflow pulverizer shown in FIG. The coarse powder has a pressure of 6.0 kg / cm ² (G) and a pressure of 6.0 kg / cm ² (G).
After finely pulverizing with the pulverizer using compressed air of Nm ³ / min, the air flow shown in FIG. 13 is again obtained while mixing the finely pulverized material with the toner pulverized raw material supplied at the raw material introduction unit. The mixture was circulated through a classifier to perform closed-circuit pulverization. on the other hand,
The fine powder classified by the air classifier is collected by the cyclone 30 while being accompanied by the suction air from the exhaust fan, and then introduced into the second classification means having the configuration shown in FIG. , Classified. Then, a classified product consisting of a group of particles having a prescribed particle size was collected by the cyclone 23. As a result, the weight average particle diameter was 6.5 μm and the particle diameter was 4.0.
It contains 28% by number of particles having a particle size of μm or less and has a particle size of 10.08 μm.
A medium powder having a particle size distribution containing 1.6% by volume of m or more particles was obtained with a classification yield of 59%. Thus, both the processing efficiency and the classification efficiency were inferior to those of Examples 4 and 5.

Table 1 Apparatus systems of Examples and Comparative Examples and classification / crushing results

[0091]

As described above, according to the present invention, a toner product having a small particle size and a sharp particle size distribution free from agglomerates and ultrafine powders can be obtained by a simple toner production method. High processing efficiency and high classification yield can be obtained. In addition, toner fusing, agglomeration, and coarsening in the classifying and pulverizing steps of toner production can be effectively prevented, and the abrasion of the device due to toner components can be effectively prevented. As a result, high-quality toner can be continuously and stably manufactured. Further, according to the present invention, when used for image formation, compared with the conventional method, it is possible to obtain an excellent image having stable image density and high durability, and having no image defects such as fogging and poor cleaning. As a result, a toner for developing an electrostatic charge image having a sharp predetermined particle size distribution with a small particle size can be obtained at low cost. In particular, according to the present invention, it is possible to efficiently obtain a toner having a fine particle size of 10 μm or less having a weight average particle size having a sharp particle size distribution. It is possible to efficiently obtain a toner having a fine particle diameter of 8 μm or less.

[Brief description of the drawings]

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

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

FIG. 3 is a schematic sectional view of a classifier used in a first classifying step in the present invention.

FIG. 4 is a schematic cross-sectional view showing a specific example of a collision type airflow pulverizer used in the present invention.

FIG. 5 is a diagram illustrating an example of a collision member in FIG. 4;

FIG. 6 is an enlarged view of a grinding chamber in FIG.

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

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

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

FIG. 10 is a sectional view taken along the line D-D 'in FIG.

FIG. 11 is a schematic cross-sectional view showing another specific example of the collision type air flow pulverizer used in the present invention.

FIG. 12 is a schematic cross-sectional view showing a specific example of a rotary airflow classifier used in the second classifier in the present invention.

FIG. 13 is a schematic cross-sectional view of an example of a classifier used for a classification means of a comparative example.

FIG. 14 is a flowchart for explaining a conventional manufacturing method.

FIG. 15 is a schematic sectional view of a conventional collision-type airflow pulverizer.

FIG. 16 is an apparatus system diagram for performing a manufacturing method of a comparative example.

[Explanation of symbols]

 1: First classifier 2, 23, 30: Collection cyclone 4: First coarse powder discharge pipe 5: First fine powder discharge pipe 6: Ultra fine powder 7: Classification room 8: Classification plate 9: Fine powder discharge Chute 10: Lower hopper 11: Classifying louver 12: Classifying air 14: Main casing 15: Raw material straightening plate 16: Finely pulverized material inlet 17: Guide chamber 18: Lower casing 19: Coarse powder outlet 21: First quantitative feeder 22: Second classifier 28: Air flow type fine pulverizer 35: Injection feeder 40: High pressure gas injection nozzle 41: Pulverized object supply pipe 42: Pulverized object 43: Acceleration pipe 44: Acceleration pipe throat part 45: High pressure gas injection nozzle Throat parts 46, 101: crushed material supply port 47, 102: high pressure gas supply port 48, 103: high pressure gas chamber 49, 92: high pressure gas introduction pipe 50, 163: acceleration pipe outlet 1, 164: collision member 52, 52 ', 166: collision surface 53, 168: pulverization chamber 54: pulverization chamber side wall 55, 167: pulverized material discharge port 61: collision member edge end 62: pulverization chamber front wall 91: collision Member supports 121, 201: body casing 122: classification chamber 123: guide chamber 124: classification rotor 125: raw material inlet 126: air inlet 128: frequency converter 129: fine powder discharge pipe 130, 134: fine powder collecting means 131: Suction fan 132: Hopper 133: Rotary valve 135: Classification louver 161: High pressure gas supply nozzle 165: Powder material supply port 168: Pulverizing chamber 201: Main casing 202: Lower casing 203: Hopper 204: Classification chamber 205: Guide chamber 206: upper cover 207: louver 208: supply cylinder 209: classification louver 210: classifying plate 211: coarse powder discharge port 212: fine powder discharge chute 213: upper casing

Claims (2)

[Claims] 1. A mixture containing at least a binder resin and a colorant is melt-kneaded, and after cooling the obtained kneaded product,
A powdered raw material comprising a coarsely pulverized product obtained by pulverizing the cooled product by a pulverizing means is first introduced into a first classification step to classify into a first fine powder and a first coarse powder, and then classified. Using the first fine powder as a classified product for producing a toner, and using the first coarse powder classified in the first classification process as a material to be crushed, an acceleration tube and a crushing device for conveying and accelerating the material to be crushed by high pressure gas A crushing chamber for finely crushing the material, and a collision member having a collision surface provided opposite to the opening surface of the outlet of the acceleration tube is provided in the crushing chamber; Has a pulverized material supply port for supplying the pulverized substance into the acceleration tube, and the collision surface is formed by a protruding central portion having a protruding center and a conical outer collision surface provided on the outer periphery thereof. And a side for further crushing the object to be crushed by the collision member into the crushing chamber by collision. And then pulverize the finely pulverized material into a classification chamber with a raised center at the bottom of the classification chamber, and into the classification chamber. A classification louver for generating a flow, and introduced into a first classification step in which the powder particles are swirled by an airflow flowing into the classification chamber via the classification louver, centrifuged, and the powder is classified. Then, after classifying into first coarse powder and first fine powder, the classified first coarse powder is introduced into the second classifying means of the second classifying step, and further classified into second coarse powder and second fine powder. Producing the classified second coarse powder again by introducing the classified second coarse powder into the above-mentioned impingement type air current pulverizer, crushing the second coarse powder, and circulating the second fine powder into a classified product for producing a toner; Method. 2. A raw material straightening plate and a finely pulverized material inlet are provided in a flow path between a collision type air flow pulverizer and a classifying chamber of a classifier used in the first classifying step, and a dispersed particle flow is provided. 2. The method according to claim 1, wherein the toner is introduced into a classifying chamber of the classifier.