JPH08299827A - Mechanical grinder - Google Patents

Abstract

PURPOSE: To finely grind roughly ground matter, in an apparatus wherein a cylinder having grooves provided to the outer peripheral surface thereof is arranged in a cylindrical container having grooves provided in the inner peripheral surface thereof and grinding is performed by air laminar flow and eddy current motion generated in a gap by accompanying the rotation of the cylinder, by forming projections in the grooves of the inner peripheral surface of the cylindrical container. CONSTITUTION: A grinder suitable for producing fine particles of a toner with a small particle size for developing an electrostatic latent image is equipped with a freely rotatably cylinder (rotor) 1 having grooves provided in the outer peripheral surface thereof and a cylindrical container 2 provided with a liner 2 having grooves provided in the inner peripheral surface thereof in its rotary axis direction attached thereto. Vortex air streams and pressure vibration are generated by the high speed rotation of the rotor and a raw material is sucked from a suction port 3 to be supplied to a grinding chamber not only to be ground by vortex air streams but also raised under rotation to be discharged from an exhaust port 4. In this case, by providing projections 7 in the grooves provided in the liner 2, it is eliminated that particles with a particle size of above 100μm are mixed with ground toner particles.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crusher suitable for producing fine powder particles such as toner for developing electrostatic latent images having a small particle size used in electrophotography, electrostatic recording and electrostatic printing. .

[0002]

2. Description of the Related Art In general, toner fine particles used for developing an electrostatic latent image are prepared by mixing and kneading a binder resin, dyes and pigments, and other additives, and then crushing the obtained kneaded product.
It is obtained by finely pulverizing the coarsely pulverized product, classifying the coarse powder, and further classifying the fine powder.

Means for finely pulverizing the coarsely pulverized product include, for example, a pulverizer for pulverizing with a cutter and a mesh which rotate at high speed, a hammer mill or a turbo mill in which shearing occurs between clearances between a hammer and liner which rotate at high speed, A pin mill that performs shear by rotating a pin protruding on a disk at high speed, a Kriptron crusher that performs shearing and grinding between a large rotor and a liner, and put the object to be crushed on jet air to collide with a collision plate There are jet mills and the like for crushing.

Conventionally, when a toner having an average particle size of about 11 μm is produced by such a method, a large one is a coarsely pulverized product having a particle size of 2000 to 2500 μm and finely pulverized at once to a small particle size. Was.

However, in the finely pulverized toner particles, large particles (referred to as coarse powder) having a particle diameter of more than 100 μm are mixed. It was necessary to remove such large particles for use as a toner. The large particles thus removed had to be finely pulverized again, and therefore had to be returned to the pulverizer again. However, this necessitates a device for cutting coarse powder in the toner manufacturing process, which causes a problem in terms of plant capital investment. Also, to return the coarse powder to the crusher,
It also has an adverse effect on improving the processing capacity.

On the other hand, if an attempt is made to manufacture a toner having a small particle diameter so as not to contain coarse powder with the above-mentioned apparatus, a large amount of energy is required, the production capacity is lowered and the cost is increased.
Further, even if the toner is manufactured in this manner, a large amount of toner particles due to overpulverization are mixed. In the case of a two-component toner, since this ultrafine powder easily adheres to the carrier, the spent on the carrier is likely to occur, causing a problem in durability.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and a coarsely pulverized product is suddenly treated to have a particle size of 11 μm.
Even if finely pulverized to particles, coarse powder does not mix, coarse powder classification processing is unnecessary in the toner manufacturing process, and an object thereof is to provide a mechanical pulverizer that enables simplification of a plant. To do.

[0008]

That is, the present invention provides a rotation-free cylinder having a groove on the outer peripheral surface of a cylindrical container having an inner peripheral surface with a predetermined gap from the inner peripheral surface. In a mechanical crusher for crushing by laminar flow and vortex motion of air generated in the gap as the cylinder rotates, the groove on the inner peripheral surface extends in the rotation axis direction of the cylinder. And a protrusion inside the groove.

In the mechanical crusher of the present invention, even if the coarsely pulverized product is finely pulverized at once into particles having a particle size of 11 μm, coarse powder is not mixed in, and no coarse powder classification treatment is required in the step of producing fine particles such as toner. It can be used in a simple open circuit, which enables facility costs to be suppressed through simplification of the plant.

In the crusher of the present invention, a freely rotatable cylinder having a groove on its outer peripheral surface is arranged inside a cylindrical container having a groove on its inner peripheral surface with a predetermined gap from the inner peripheral surface. . A schematic configuration diagram of such a crusher is shown in FIG.

The freely rotatable cylinder (1) has a large number of grooves on the outer peripheral surface in the direction of the rotation axis and is called a rotor (1). The cylindrical container (2) is fitted with a liner (2) having a large number of grooves on the inner surface in a cut shape in the rotation axis direction. Then, when the rotor (1) rotates at high speed to generate a strong vortex flow and pressure oscillation in the machine, the raw material is sucked together with air from the intake port (3) and is supplied to the crushing chamber by the air flow. Subsequently, it is pulverized by a violent vortex of air, rises while rotating along the rotor (1), and is discharged together with air from the exhaust port (4). The gap between the rotor (1) and the liner (2) is usually about 1 mm.

Conventionally, the groove provided in the liner is shown in FIG.
As shown in (a), there was no obstacle in the axial direction of the cylindrical container to which the liner was attached, and it was provided as a stony space.

In the present invention, the groove is provided with a crimp. Specifically, as shown in FIG. 3 (b), one or more holes (7) are installed in the groove (6) of the liner. Toner particles crushed by such an apparatus have a particle size of 100 μm.
No more than 100 particles are mixed in, and it is no longer necessary to perform coarse powder classification treatment in the fine powder manufacturing process for toner and the like and to perform fine pulverization again.

FIG. 3 (c) is a sectional view of the liner according to the present invention when the central portion of the groove is cut in the extending direction of the groove. When the depth of the groove (6) of the liner is H ₀ , the thickness D ₁ of the crimp is 0.5H _{0 to} 2H ₀ . Preferably 0.
It is 8H _{0 to} 1.2H ₀ . If D ₁ is less than 0.5H ₀ , the effect of crimping is lost, and if it exceeds 2H ₀ , the load becomes too large. Liner groove depth H ₀ is usually 2-5 m
m, preferably 3 to 4 mm. If the depth is less than 2 mm, the load will be too large and the pulverizability will be deteriorated.

The groove of the liner for attaching the crimp according to the present invention may be a liner groove which has been used conventionally, and a cross section perpendicular to the extending direction of the groove is as shown in FIGS. 2 (a) and 2 (b). It has a shape. The liner groove shown in FIG. 2 (a) has an isosceles triangular cross section, and the repeating unit R is 5 to 9 mm, preferably 7 to 8 mm.
If it is less than 5 mm, the load becomes too large, and if it is more than 9 mm, the pulverizability decreases. Groove depth H ₀ is 2-5 mm
And preferably 3 to 4 mm. If it is shallower than 2 mm, the load becomes large and the pulverizability deteriorates, and if it is deeper than 5 mm, the number of dips increases. The cross-sectional shape of the liner groove shown in FIG. 2B is a right triangle, and the repeating unit T is 5 to 9 m.
m, preferably 7 to 8 mm. If it is smaller than 5 mm, the load becomes large and the pulverizability is deteriorated, and if it is larger than 9 mm, the number of jumps increases. The proportion of the length U occupied by the inclined portion is 70 to 100%, preferably 70 to 80% of the length of T. If it is less than 70%, the load becomes too large. The depth H _{0 of the} groove is 2 to 5 mm,
It is preferably 3 to 4 mm. If it is shallower than 2 mm, the load becomes large and the pulverizability deteriorates, and if it is deeper than 5 mm, the number of dips increases.

FIG. 2 is a sectional view of the liner groove shown in FIG. 2 (b), to which the shim (7) according to the present invention is attached.
It is shown in (c). When the depth of the groove (6) is H ₀ , the depth H ₁ of the hollow (7) is 0.5H _{0 to} 0.8H ₀ , preferably 0.6H _{0 to} 0.7H ₀ . If H ₁ is less than 0.5H _0, the effect of preventing coarse powder from jumping in is lost, and if it exceeds 0.8H ₀ , the load becomes too large. This relationship also applies to the case where a crimp is attached to a liner groove having an isosceles triangular cross-sectional shape shown in FIG.

When the shikiri is installed at a position closer to the upper end of the liner, the load on the liner is gradually increased, and when it is closer to the lower end of the liner, the load is gradually increased.
The effect of the shikiri is lost. Therefore, when attaching one partition, when the position of the divider with the E ₀ of the height of the liner, and at the bottom surface of the E _0/2, when mounting the two partition, the position of these dividers, it is preferable that the E _0/3 and 2E _0/3 from the bottom. In other words, it is preferable that the positions of the crimps to be attached are such that the height of the liner is equally divided by the number. The preferred number of crickets is two. Further, this mounting position may be mounted in each groove of the liner, may be mounted in each of two or more grooves, and may be random or regularly if the balance is good. However, it is preferable to install a crimp in all the grooves. The height E _{0 of the} liner differs depending on the model, but is equal to the length of the rotor.

The material of the shikiri is not particularly limited as long as it has appropriate hardness and strength so as not to be crushed during rotation, but in consideration of durability, the same material as the liner is desirable.

As a measure to prevent the mixture of coarse powder,
It is also effective to give the liner groove one or more inflection points, that is, to form the groove in a zigzag shape on the liner. A schematic development view of the liner is shown in FIG.

In FIG. 4, two inflection points (9) are shown per groove. The number of inflection points is 1 to 5, preferably 2 to 3. The number of inflection points must be set in consideration of the angle (x in FIG. 4) at the inflection point of the zigzag groove (8). That is, even if the number of inflection points is set within the above-mentioned allowable range, for example, if the number of inflection points is set as the upper limit and the angle (x) is made as small as possible, the load is excessively applied to the liner and the crushing is performed. The operation of the machine becomes impossible and the effect of the present invention cannot be obtained. Therefore, if a load is applied to the liner within the allowable range by increasing the number of inflection points, it is necessary to set the angle so that the load on the liner caused by setting the angle is not too large. On the contrary, if the liner is loaded by reducing the angle, which is within the allowable range, it is necessary to set the number so that the load on the liner due to the inflection point is not too large. is there.

It is also possible to combine the above-mentioned crimping and zigzag forming of the liner groove and apply it to the liner. However, in this case as well, similar to the relationship between the angle of the zigzag liner groove and the number of inflection points, when the load is applied to the liner within the allowable range due to the zigzag of the liner groove, the number of crimps to the liner groove is increased. Must be restricted,
On the contrary, it is necessary to limit the zigzag formation when the liner loads the liner, although it is within an allowable range.

As for the cross-sectional shape of the zigzag groove, particularly the cross-sectional shape perpendicular to the traveling direction of the groove, the cross-sectional shape of the commonly used liner groove shown in FIGS. 2A and 2B can be applied. The values described above can be adopted for H ₀ , R, T, and U in the figure.

It is considered that in a commonly used crusher, volume crushing is mainly performed in the lower part and surface crushing is performed in the upper part. In the volume pulverization, the coarsely pulverized material flowing in from the lower side together with the airflow is pulverized so as to reduce the volume, and relatively large numbers of coarse particles are generated. Surface grinding means that the surface is ground and the shape is rounded. In the crusher according to the present invention, the liner groove is provided with a crimp or the liner groove is formed into a zigzag shape so that the coarse powder can be prevented from slipping off and volume pulverization can be performed with a certain probability even in the upper portion, and the fine powder can be obtained. It is considered possible to prevent the mixture of coarse powder into the inside.

As another condition for operating the crusher of the present invention, the coarsely crushed material is fed by cold air of about 5 ° C. or less, and the total air volume varies depending on the model, but 4 to 6 m ^{3 at a} rotor diameter of about 180 mm. / Min, that is, 50% or more of the conventional amount is increased. This makes it possible to prevent fusion to the rotor and liner and blockage of the powder in the crusher. If the cold air temperature exceeds 5 ° C, fusion to the rotor and liner will start, and if the total air volume is less than 4 m ³ / min, it will not be possible to prevent clogging of the powder inside the crusher, and if it exceeds 6 m ³ / min, a blower, etc. Will have to improve their abilities.

The present invention will be described in more detail by the following examples.

[0026]

Example 1 100 parts by weight of styrene-acrylic copolymer resin (Mn: 5000, Mn / Mw: 28) 8 parts by weight of carbon black (MA # 8; manufactured by Mitsubishi Chemical Industry Co., Ltd.) Nigrosine dye ( Nigrosine base EX; manufactured by Orient Chemical Industry Co., Ltd.) 5 parts by weight Low molecular weight polypropylene (Viscor 550P; manufactured by Sanyo Chemical Industry Co., Ltd.) 2 parts by weight

The above raw materials were mixed by a ball mill and kneaded by a continuous extruder (made by Ikegai Tekko Co., Ltd.). After that, it is cooled with a cooling roller and a cooling conveyor, coarsely crushed with a feather mill (manufactured by Hosokawa Micron Co., Ltd.), and has an average particle diameter of 1 m.
m coarsely pulverized product was obtained. Then, the liner portion of the rotor rotary type crusher (KTM0 type; manufactured by Kawasaki Heavy Industries, Ltd.) was replaced with a liner having the following slits in all grooves, and the flow rate was 4.5 m ³ / min and the peripheral speed was 130 m. The coarsely pulverized product was pulverized at a speed of about 1 / sec.

Liner conditions: cross-sectional shape of liner groove; similar to FIG. 2 (c), H ₀ = 3.5 mm, T = 8 mm, U =
Depth of 7mm partition; H ₁ = 0.7 H ₀ partition thickness; D ₁ = H ₀ number of partition per groove one; 2 (position E _0/3 from the bottom surface of the liner and 2E _0/3)

The particle size distribution of the obtained particles was examined by a Coulter counter type TAII. As a result, the average particle size was 11.0 μm, and the particles having a particle size of 20 μm or more had an average particle size of 0.
15% was present, but no particles of 105 μm or larger were present. After that, the toner particles having the target particle diameter could be obtained only by classifying the fine powder.

Example 2 A coarsely pulverized product was obtained in the same manner as in Example 1. And, except that the liner portion was replaced with a liner having the following crimps attached to all the grooves and the air volume was set to 6 m ³ / min,
The coarsely pulverized product was pulverized in the same manner as in Example 1.

Liner conditions: cross-sectional shape of liner groove; similar to FIG. 2 (c), H ₀ = 3.5 mm, T = 8 mm, U =
Depth of 7mm partition; H ₁ = 0.8H ₀ partition thickness; D ₁ = 2H ₀ number of partition per groove one; 2 (position E _0/3 from the bottom surface of the liner and 2E _0/3)

The particle size distribution of the obtained particles was examined in the same manner as in Example 1. As a result, the average particle size was 11.2 μm, and 0.10% of the particles having a particle size of 20 μm or more were present, but the particles of 105 μm or more were not present. After this,
It was possible to obtain toner particles having a target particle diameter simply by classifying fine particles.

Example 3 A coarsely pulverized product was obtained in the same manner as in Example 1. Then, the coarsely pulverized product was pulverized in the same manner as in Example 1 except that the liner portion was replaced with a liner having the following grooves formed in a zigzag shape.

Liner conditions: cross-sectional shape of liner groove; similar to FIG. 2A, H ₀ = 3.5 mm, R = 7.5 mm Inflection point of zigzag groove; 2 (position E from the bottom of the liner _0/3 and 2E _0/3) the angle of the zigzag grooves; x = 85 °

The particle size distribution of the obtained particles was examined in the same manner as in Example 1. As a result, the average particle size was 10.8 μm, and 0.10% of the particles having a particle size of 20 μm or more were present, but the particles of 105 μm or more were not present. After this,
It was possible to obtain toner particles having a target particle diameter simply by classifying fine particles.

Example 4 A coarsely pulverized product was obtained in the same manner as in Example 1. Then, the coarsely pulverized product was pulverized in the same manner as in Example 1 except that the liner portion was replaced with a liner having the following grooves in a zigzag shape and the air flow rate was 6 m ³ / min.

Liner conditions: sectional shape of liner groove; similar to FIG. 2A, H ₀ = 3.5 mm, R = 7.5 mm Inflection point of zigzag groove; 3 (position E from the bottom of the liner _0/4, E _0/2 and 3E _0/4) the angle of the zigzag grooves; x = 90 °

The particle size distribution of the obtained particles was examined in the same manner as in Example 1. As a result, the average particle size was 10.5 μm, and 0.10% of the particles having a particle size of 20 μm or more were present, but the particles of 105 μm or more were not present. After this,
It was possible to obtain toner particles having a target particle diameter simply by classifying fine particles.

Example 5 A coarsely pulverized product was obtained in the same manner as in Example 1 except that the toner raw materials in Example 1 were changed as follows.

100 parts by weight of polyester resin (Mn: 6800, Mw: 86000, gel fraction: 9%) 8 parts by weight of carbon black (MA # 8; manufactured by Mitsubishi Chemical Industry Co., Ltd.) Cr-containing oil-soluble dye (Bontron N-01; manufactured by Orient Chemical Industry Co., Ltd.) 2 parts by weight Low molecular weight polypropylene (Viscor TS200P; manufactured by Sanyo Chemical Industry Co., Ltd.) 2 parts by weight

Then, the coarsely pulverized product was pulverized in the same manner as in Example 1.

The particle size distribution of the obtained particles was examined in the same manner as in Example 1. As a result, the average particle size was 11.5 μm, and 0.18% of the particles having a particle size of 20 μm or more existed, but the particles of 105 μm or more did not exist. After this,
It was possible to obtain toner particles having a target particle diameter simply by classifying fine particles.

Comparative Example 1 A coarsely pulverized product was obtained in the same manner as in Example 1. Then, the coarsely pulverized product was pulverized in the same manner as in Example 1 except that the liner portion was replaced with the following liner without crimp and the air flow rate was changed to 2 m ³ / min.

Liner conditions: cross-sectional shape of liner groove; similar to FIG. 2 (b), H ₀ = 3.5 mm, T = 8 mm, U =
7 mm

The particle size distribution of the obtained particles was examined in the same manner as in Example 1. As a result, the average particle size was 12.0 μm, and 0.31% of the particles having a particle size of 20 μm or more were present.
There was 0.22% of particles having a size of 05 μm or more. The pulverized product contained a large amount of coarse powder and could not be used as it was, and it was necessary to classify the coarse powder and pulverize again.

The above results are summarized in Table 1.

[0047]

[Table 1]

As in Examples 1 to 2 and 5, a specified crimp is attached to the groove on the inner peripheral surface of the liner, or as in Examples 3 to 4, the groove is zigzag as specified, thereby forming a rough surface. It has been clarified that it is possible to manufacture toner particles having an average particle size of about 11 μm, in which no powder is mixed. As a conventional technique, the pulverized product obtained in Comparative Example 1 has a particle size of 105
Particles with a size of μm or more were mixed in, and it was not possible to obtain the intended toner particles without classifying not only fine powder but also coarse powder.

[0049]

EFFECTS OF THE INVENTION Even if a coarsely pulverized product is finely pulverized all at once into particles having a particle size of 11 μm, coarse powder is not mixed, and it can be used in an open circuit which does not require coarse powder classification treatment in the toner manufacturing process.
Therefore, the equipment cost can be suppressed by simplifying the crushing plant.

[Brief description of drawings]

FIG. 1 shows a schematic configuration diagram of an impact crushing device in a high-speed air stream.

2A and 2B are schematic cross-sectional views of a liner groove perpendicular to the groove extending direction, and FIG. 2C is a schematic cross-sectional view of a liner groove with a crimp attached perpendicular to the groove extending direction. Show.

3A is a perspective view of a part of a groove of a conventional liner, FIG. 3B is a perspective view of a part of a liner groove with a crimp, and FIG. 3C is an extension of the liner groove of FIG. 3B. FIG.

FIG. 4 is a schematic development view of a liner having a zigzag groove according to the present invention.

[Explanation of symbols]

1: Free-rotating cylinder (rotor), 2: Cylindrical container (liner), 3: Intake port, 4: Exhaust port, 5: Electric motor, 6:
Groove, 7: crimp, 8: zigzag groove, 9: inflection point

Claims (2)

[Claims] 1. Inside a cylindrical container having a groove on its inner peripheral surface,
A rotation-free cylinder having a groove on the outer peripheral surface is arranged with a predetermined gap from the inner peripheral surface, and pulverization is performed by laminar flow and vortex motion of air generated in the gap as the cylinder rotates. In the mechanical crusher to be performed, the groove of the inner peripheral surface is extended in the rotation axis direction of the cylinder, and a protrusion is provided inside the groove. 2. Inside a cylindrical container having a groove on its inner peripheral surface,
A rotation-free cylinder having a groove on the outer peripheral surface is arranged with a predetermined gap from the inner peripheral surface, and pulverization is performed by laminar flow and vortex motion of air generated in the gap as the cylinder rotates. The mechanical crusher according to claim 1, wherein the groove on the inner peripheral surface extends in a zigzag shape in the rotation axis direction of the cylinder.