JP2663041B2 - Collision type air crusher - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a collision type air flow pulverizer using a jet air flow (high-pressure gas).

In particular, the present invention relates to a collision-type airflow pulverizer for efficiently generating a toner or a colored resin powder for a toner used in an image forming method by electrophotography.

[Prior Art] Conventionally, a collision type airflow pulverizer using a jet airflow transports a powdery raw material by a jet airflow, collides the powdery raw material with a collision member, and pulverizes the powdery raw material by the impact force.

 FIGS. 4 and 5 show an example of such a collision type airflow pulverizer.

In the pulverizer shown in FIG. 4, a powdery raw material having a coarse particle size is supplied from an inlet 1 to an acceleration tube 3 and is jetted from a jet nozzle 2 so that the powdery raw material is collided with a collision surface of a collision member 4. The powder is beaten to 14 and crushed by the impact force, and is discharged from the discharge port 5 to the outside of the crushing chamber. However, when the collision surface 14 is perpendicular to the axial direction of the acceleration tube 3, the ratio of the raw material powder blown out from the jet nozzle 2 and the powder reflected by the collision surface 14 coexist near the collision surface 14 is high. Therefore, the powder concentration in the vicinity of the collision surface 14 increases, and the crushing efficiency is not good. Further, the primary collision at the collision surface 14 is mainly performed, and it cannot be said that the secondary collision with the crushing chamber wall 6 is effectively used. Furthermore, the angle of the collision surface is
On the other hand, in a vertical crusher, when crushing a thermoplastic resin, fusion and agglomerates are apt to be generated due to local heat generation at the time of collision, which makes stable operation of the device difficult and causes a reduction in crushing ability. . For this reason, it has been difficult to increase the powder concentration for use.

In addition, the fused material formed on the collision surface gradually grows and peels off at a certain stage, which may cause clogging at the input port 1 of the crusher. It must be cleaned and inspected.

This is particularly noticeable when a toner or a colored resin powder for a toner used in an image forming method by an electrophotographic method is manufactured.

The toner or the colored resin powder for a toner used in the image forming method by the electrophotographic method usually contains at least a binder resin and a colorant or a magnetic powder. The toner develops the electrostatic charge image formed on the latent image carrier, and the formed toner image is transferred to a transfer material such as plain paper or a plastic film, and is heated and fixed, a pressure roller is fixed, or a heat and pressure roller is used. The toner image on the transfer material is fixed to the transfer material by a fixing device such as a fixing unit. Therefore, the binder resin used for the toner has a property of being plastically deformed when heat and / or pressure is applied.

At present, the toner or the colored resin powder for the toner is prepared by melt-kneading a mixture containing at least a binder resin and a colorant or a magnetic powder (containing a third component, if necessary),
It is prepared by cooling the melt-kneaded product, pulverizing the cooled product, and classifying the pulverized product. The crushing of the cooled product is usually carried out by a mechanical crusher (or a medium crusher), and then the crushed coarse powder is finely crushed by an impinging airflow crusher using a jet stream.

When pulverization is performed using a collision type air flow pulverizer using the jet air flow, fusion due to local heat generation at the time of collision with the collision surface is likely to occur, and thus the processing capacity may have to be reduced.

In addition, as shown in FIG. 5, when the collision surface 14 is inclined at an angle of 45 ° with respect to the accelerating tube, the above-mentioned problems are small when pulverizing the thermoplastic resin. However, since the impact force used for crushing at the time of collision is small and the crushing due to secondary collision with the crushing chamber wall 6 is small, the crushing ability is 1/2 to 1 / compared to the crusher of FIG. The crushing ability drops to 1.5. Therefore, there is a demand for a collision-type airflow pulverizer having a high pulverization capacity and free from fusion.

[Problems to be Solved by the Invention] In view of the above-mentioned problems of the prior art, an object of the present invention is to provide a collision-type airflow pulverizer for efficiently pulverizing a powder mainly composed of a thermoplastic resin. It is in. That is,. In particular, it is intended to provide a collision-type airflow pulverizer in which the powder material and the pulverized powder in the pulverization chamber are less likely to be fused. 2. To provide a collision-type air-flow pulverizer in which the fusion of the powder raw material and the pulverized powder is suppressed and the generation of agglomerates and coarse particles is reduced even when the processing amount of the powder raw material is increased. Polyester resin or styrenic resin (for example,
(1) to provide a collision-type air-flow pulverizer capable of efficiently pulverizing a powder raw material mainly composed of a thermoplastic resin such as a styrene-acrylate copolymer or a styrene-methacrylate copolymer; (1) To provide a collision-type airflow pulverizer capable of efficiently producing toner or colored resin particles for toner used in copiers and printers having a heating and pressing roller fixing means; It is still another object of the present invention to provide an impinging airflow pulverizer capable of efficiently pulverizing resin particles having an average particle size of 20 to 2000 μm to an average particle size of 5 to 15 μm.

[Means and Actions for Solving the Problems] The feature of the present invention is that the powder ejected from the accelerating tube is subjected to a collision force in the downstream of a horizontal accelerating tube for conveying and accelerating the powder by a high-pressure gas. In a collision type air current pulverizer in which a collision chamber for pulverizing is provided with a collision member opposed thereto so that powder can be pulverized on a collision surface of the collision member, the collision surface is a conical collision surface. And an impact-type pulverizer having a jet branch point on the jet center line and having a collision surface jet length above the junction point shorter than that below the jet surface.

Further, the tip of the collision surface of the collision member has an apex angle of 110
It is also characterized by a conical impingement airflow pulverizer having a shape of {-175}.

Hereinafter, the configuration and operation of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a schematic cross-sectional view of an impinging airflow pulverizer which is an example of the present invention, and a diagram showing a pulverizing means which combines a pulverizing step using the pulverizer and a classification step using a classifier.

Here, the powder material 7 to be pulverized is supplied to the accelerating tube 3 from the powder material input port 1 provided on the pulverizer wall 11 above the accelerating tube 3. A compressed gas such as compressed air is introduced into the acceleration tube 3 from the compressed gas supply nozzle 2, and the powder material 7 supplied to the acceleration tube 3 is instantaneously accelerated to have a high speed.

The powdery raw material 7 discharged from the acceleration pipe outlet 13 into the pulverizing chamber 8 at a high speed collides with the collision surface 14 of the collision member 4 and is pulverized.

In the pulverizer shown in FIG. 1, the collision member 4 has a conical shape having an apex angle of 160 ° and the upper surface of the collision surface is removed. FIG. 2 shows the first
FIG. 2 is a diagram schematically showing a cross section taken along the AB plane of the impingement type air current pulverizer shown in the figure, and schematically shows a dispersion state of the powder after collision at the collision surface 14.

The powdery raw material 7 ejected from the acceleration tube outlet 13 into the pulverizing chamber 8 at a high speed collides with the collision surface 14 of the collision member and is pulverized. In the pulverizer of the present invention, the collision surface has a cone shape. Therefore, the powder is satisfactorily diffused in the circumferential direction of the collision member on the collision surface, so that the crushing chamber wall 6 is widely used for the secondary collision. Therefore, the concentration of the powder in the vicinity of the collision surface 14 does not increase, so that the processing efficiency of the powder can be improved and the fusion of the powder on the collision surface 14 can be satisfactorily suppressed. Further, by cutting out the upper part of the collision surface 14, the growth of fusion is prevented.

What led to the present invention is that, when the behavior of the powder in the crushing chamber 8 is visually observed, there is a characteristic in the flow of the powder.
This is due to the discovery that there is a certain pattern in the fusion occurring on 14.

That is, in the pulverizing chamber 8, the powder flow is not a uniform flow, and the powder flow ejected from the accelerating tube 3 is roughly divided into upper and lower powder flows.
It turned out that there was a book flow. A relatively large particle size flows into the flow which is ejected from near the lower part of the acceleration tube 3 and collides with the collision surface 14, while the flow which is ejected from near the upper part of the acceleration tube 3 and collides with the collision surface 14 is It was confirmed that the sample contained many particles having a small particle size. In addition, the collision surface
It was found that the fusion occurring at 14 did not occur over the entire collision surface, but rather violently near the outer periphery of the collision surface, especially near the upper periphery.

By analogy with this, it can be considered that the powder flow flowing downward contains many coarse particles, so the impact force on the collision surface 14 is strong, and the effect of scraping the collision surface rather than fusion is large. Can be Therefore, even if fusion occurs, the function of scraping the fusion material works, and the fusion does not grow beyond a certain level.

On the other hand, the powder flow flowing upward has many fine particles, so that the impact force on the collision surface 14 is weak, and the dust concentration is high, so that fusion is likely to occur. When observing the growth process of the fusion, it was confirmed that the fusion occurred from the upper outer periphery of the collision member and gradually became the center.

Therefore, in order to solve this problem, it was considered that the portion where fusion occurred and grew did not originally contribute to pulverization, and an attempt was made to delete the upper portion of the collision surface. That is, as shown in FIGS. 1 and 2, the jet branch point on the collision member on the jet center line
The length of the impingement jet above 16 is shorter than the length of the impinging jet below the branch point 16.

With this configuration, the fusion at the upper portion of the collision surface 14 was almost completely eliminated, and no reduction in crushability was observed.

That is, it is considered that this configuration brings about the following operation. When the same kinetic energy is applied to the powder ejected from the accelerating tube 3, the powder having a small mass, that is, a powder having a small particle diameter is given a large velocity due to the law of conservation of momentum, while the coarse powder having a large mass is given. The particles will be given a small velocity. Alternatively, since gravity acts on each powder, the resultant vector draws a parabola by a horizontal velocity component and an acceleration component due to gravity.

In view of the above kinetic theory, it is considered that fusion to the collision surface below the branch point 16 is unlikely to occur, while fusion to the collision surface above the branch point 16 is likely to occur. Thus, by shortening the distance flowing along the upper collision surface, that is, the length of the collision surface jet, fusion can be suppressed and continuous pulverization can be performed.

How much of the upper collision surface jet length is deleted
What is necessary is just to determine after the collision pattern of the powder with the collision surface 14 is investigated in advance. Since this collision pattern changes depending on the specific gravity and particle size of the powder, the shape of the pulverizing chamber, the method of charging the raw materials, and the like, the shape of the collision surface is limited to those shown in FIGS. What is necessary is just to design suitably.

The pulverizer having such a configuration is particularly effective when pulverizing toner or toner colored resin powder used in an image forming method by electrophotography.

Since the binder resin used in such a toner has a property of plastic deformation when heat and / or pressure is applied, fusion and agglomerates are more likely to occur due to local heat generation at the time of collision during pulverization. . For this reason, fusion occurs at the upper portion of the conventional collision surface having a shape as shown in FIG. 4, and this fusion grows and eventually causes clogging at the input port of the crushing machine. As a result, there is a problem that the driving cannot be continued. However, on the collision surface having the shape as shown in FIGS. 1 and 2 of the present invention, the above-described fusion does not occur,
Stable operation of the apparatus is possible, and the tip of the collision surface 14 has a conical shape, so that secondary collision with the crushing chamber wall 6 can be effectively used, and the crushability is improved. It is planned.

The effect of the present invention is more remarkable as the particle diameter of the powder is smaller, and is particularly preferable when producing a powder having a volume average diameter of 10 μm or less.

In addition, it was confirmed that the cone-shaped collision surface according to the present invention can obtain a good pulverizing treatment when the apex angle is in the range of 110 ° to 175 °.

EXAMPLES Hereinafter, the present invention will be described in detail based on examples. still,
The particle size expressions in Examples and Comparative Examples are all based on the following Coulter counter.

In other words, the Coulter Counter TA is used as a measuring device.
-Type II (manufactured by Coulter, Inc.) is connected to an interface (manufactured by Nikkaki) that outputs the number distribution and volume distribution, and a CX-1 personal computer (manufactured by Canon). Prepare a% NaCl aqueous solution. As a measuring method, 0.1 to 5 ml of a surfactant, preferably an alkylbenzene sulfonate, is added as a dispersant to 100 to 150 ml of the aqueous electrolytic solution, and 2 to 20 mg of a measurement sample is further added. The electrolyte in which the sample was suspended was treated with an ultrasonic
After a dispersion treatment for minutes, the Coulter Counter TA-II
According to the mold, the particle size distribution of the particles of 2 to 40 μm was measured on the basis of the number by using a 100 μm aperture as the aperture, and then the value according to the present invention was obtained.

Example 1 After the above materials were mixed well in a blender, they were kneaded with a biaxial kneading extruder set at 150 ° C. The obtained kneaded material was cooled and coarsely pulverized with a cutter mill to a particle size of 1 mm or less to obtain a pulverized raw material.

The obtained pulverized raw material was pulverized by a collision type air pulverizer shown in FIGS. A fixed wall type air classifier was used as a classifier 24 for classifying the pulverized powder into fine powder and coarse powder.

4.6m ³ / from compressed gas supply nozzle 2 to impingement type air crusher
min (6 kgf / cm ² ) of compressed air is introduced, and the collision surface of the collision member 4 has an apex angle of 160 °, and a cone-shaped upwardly deleted collision surface in which X and Y in FIG. 2 satisfy X / Y = 0.8. And crushed.

The pulverized raw material was supplied at a rate of 11.0 kg per hour, and pulverization was performed by adjusting classification conditions so that a product having a volume average particle diameter of 6.0 μm was obtained. As a result, as a result of continuous operation for 4 hours, almost no fusion was observed on the collision surface, and the amount of removal per hour was stable at 11.0 kg.

Example 2 After the above materials were mixed well in a blender, they were kneaded with a biaxial kneading extruder set at 150 ° C. The obtained kneaded material was cooled and coarsely pulverized with a cutter mill to a particle size of 1 mm or less to obtain a pulverized raw material.

The obtained pulverized raw material was pulverized by a collision type air pulverizer shown in FIGS. A fixed wall type air classifier was used as a classifier 24 for classifying the pulverized powder into fine powder and coarse powder.

4.6m ³ / from compressed gas supply nozzle 2 to impingement type air crusher
min (6 kgf / cm ² ) of compressed air was introduced, and a collision surface of the collision member 4 with a vertex angle of 160 ° and X and Y in FIG. 2 satisfying X / Y = 0.85 was used. And crushed.

The pulverized raw material was supplied at a rate of 18.0 kg per hour, and pulverization was performed by adjusting classification conditions so that a product having a volume average particle size of 8.0 μm was obtained. As a result, as a result of continuous operation for 4 hours, almost no fusion was observed on the collision surface, and the output per hour was stable at 18.0 kg.

Example 3 FIGS. 1 and 3 show a pulverized raw material obtained in the same manner as in Example 1.
The powder was pulverized by a collision type airflow pulverizer configured as shown in the figure. A fixed wall type air classifier was used as a classifier 24 for classifying the pulverized powder into fine powder and coarse powder.

4.6m ³ / from compressed gas supply nozzle 2 to impingement type air crusher
min (6 kgf / cm ² ) of compressed air is introduced, the lower half cylinder upper half prismatic collision member 4 has an impact surface apex angle of 160 °, and X ′ and Y ′ in FIG. 3 satisfy X ′ / Y ′ = 0.8. Grinding was carried out using a collision surface with a satisfactory cone-shaped upward deletion.

The pulverized raw material was supplied at a rate of 11.2 kg per hour, and pulverization was performed by adjusting classification conditions so that a product having a volume average particle diameter of 6.0 μm was obtained. As a result, as a result of continuous operation for 4 hours, almost no fusion was observed on the collision surface, and the amount per hour was stable at 11.2 g.

Comparative Example 1 A pulverized raw material obtained in the same manner as in Example 1 was pulverized by a conventional collision-type airflow pulverizer configured as shown in FIG.
Classifier for classifying pulverized powder into fine powder and coarse powder
As 24, a fixed wall type air classifier was used.

4.6m ³ / from compressed gas supply nozzle 2 to impingement type air crusher
Min (6 kgf / cm ² ) of compressed air was introduced, and the collision surface was perpendicular to the central axis of the accelerator tube, and the central axis of the collision member coincided with the central axis of the accelerator tube.

The pulverized raw material was supplied at a rate of 8.0 kg per hour, and pulverization was performed by adjusting classification conditions so that a product having a volume average particle diameter of 6.0 μm was obtained. Thereby, as a result of performing the continuous operation for 4 hours, fusion was observed at the upper portion of the collision surface, and when the operation was further continued, the fusion material was peeled off, and the peeled fusion material closed the raw material inlet 1, It became impossible to continue driving.

In addition, the removal amount per hour was 8.0 kg, which was clearly inferior to Example 1.

Comparative Example 2 A pulverized raw material obtained in the same manner as in Example 2 was pulverized by a conventional impingement airflow pulverizer configured as shown in FIG.
Classifier for classifying pulverized powder into fine powder and coarse powder
As 24, a fixed wall type air classifier was used.

4.6m ³ / from compressed gas supply nozzle 2 to impingement type air crusher
Min (6 kgf / cm ² ) of compressed air was introduced, and the collision surface was perpendicular to the central axis of the accelerator tube, and the central axis of the collision member coincided with the central axis of the accelerator tube.

The pulverized raw material was supplied at a rate of 13.0 kg per hour, and pulverization was performed by adjusting classification conditions so that a product having a volume average particle size of 8.0 μm was obtained. Thereby, as a result of performing the continuous operation for 4 hours, fusion was observed at the upper portion of the collision surface, and when the operation was further continued, the fusion material was peeled off, and the peeled fusion material closed the raw material inlet 1, It became impossible to continue driving.

In addition, the extraction amount per hour was 13.0 kg,
It was obviously worse.

[Effects of the Invention] As described above, according to the collision type air current pulverizer of the present invention, the generation of fusion, agglomerates, and the like during the pulverization of the powder raw material is prevented, and the apparatus can be operated stably. . In addition, since the tip of the collision surface has a cone shape, a strong impact force can be maintained until the secondary collision of the powder material. Thereby, the conventional pulverizing ability can be improved, that is, the production efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of an impinging airflow pulverizer of the present invention and an example of a flowchart of a pulverizing means in which the pulverizer and a classifier are combined. FIG. 2 is a sectional view taken along the line AB of FIG. 1 and shows a grinding chamber. FIG. 3 shows another preferred example of the collision member, and is a view showing the grinding chamber in a cross-sectional view taken along AB. FIG. 4 and FIG. 5 are a schematic sectional view of a conventional collision-type air-flow crusher and a flow chart of a crushing means. DESCRIPTION OF SYMBOLS 1 ... Powder material input port 2 ... Compressed gas supply nozzle 3 ... Acceleration tube 4 ... Collision member 5 ... Discharge port 6 ... Pulverization chamber wall 7 ... Powder material 8 ... Pulverization chamber 11 ... Crusher wall 13 Accelerator tube outlet 14 Impact surface 15 Accelerator tube center axis 16 Jet branch point on impact member 24 Classifier

 ──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Yasuhide Goseki 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (56) References JP-A-2-111460 (JP, A) JP-A 2-111461 (JP, A)

Claims (2)

(57) [Claims] A pulverizing chamber is provided downstream of a horizontal accelerating tube for conveying and accelerating powder by a high-pressure gas, in which a collision member for pulverizing the powder ejected from the accelerating tube by a collision force is disposed oppositely. A collision-type airflow pulverizer in which powder can be pulverized at the collision surface of the collision member, wherein the collision surface is a conical collision surface and has a branch point of the jet on a jet centerline. An impact-type airflow pulverizer characterized in that the impact surface jet length above the branch point is shorter than the impact surface jet length below. 2. A front end portion of a collision surface of the collision member has an apex angle.
2. The impingement type airflow pulverizer according to claim 1, wherein the impingement airflow pulverizer has a cone shape having an angle of 110 to 175 degrees.