JP2002204966A - Pulverizer, apparatus for producing toner and toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To minimize the diameter of pulverized particles and improve the sphericity. SOLUTION: Side wall surfaces 11 on the upstream side in the rotating direction from the recessed parts 10 of a stator 6 are formed at an angle of 150-180 deg. to inside surfaces 9, and side wall surfaces 12 on the downstream side in the rotating direction at an angle of 90 deg.-145 deg. to the inside surfaces 9. Materials to be pulverized 13 are processed to round off the corners by colliding against the side wall surfaces 12 on the downstream side in the rotating direction through flowing along the side wall surfaces 11 on the upstream side in the rotating direction from the recessed parts 10 of the stator 6, when the materials to be pulverized 13 is made to flow in a gap 5 between the stator 6 and a rotator 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulverizing apparatus for producing fine powder such as a dry toner for developing an electrostatic image in an electrophotographic system, an electrostatic recording system, an electrostatic printing system, etc. The toner produced thereby,
In particular, it relates to improvement of the circularity of crushed particles.

[0002]

2. Description of the Related Art For example, a mechanical pulverizer for performing micron-order pulverization to produce a toner or the like for developing a latent image formed on a photoreceptor in an electrophotographic image forming apparatus has a rotating shaft. A rotor that is supported and has a number of irregularities along a generatrix on the outer surface, and a stator that is arranged with a gap between the rotor and has a number of irregularities along the generatrix on the inner surface. Having. Then, while rotating the rotor, a solid material to be ground is supplied from a supply port provided at one end of the outer surface of the stator, and the material to be ground is predetermined between the rotating rotor and the stator. Crush to size. In order to efficiently pulverize the object to be crushed, for example, Japanese Patent Application Laid-Open
As shown in FIG. 8, the mechanical pulverizing apparatus disclosed in Japanese Patent Publication No. 93 has an inner surface of a stator 61 opposed to a rotor 41 formed into a concave portion 62 having an arch-shaped cross section. A swirling flow 63 in a rotation direction opposite to the above is generated. As shown in the schematic diagram of FIG. 9, the crushed material supplied to the crushing device collides with the rotation-direction downstream side wall surface 64 of the circular concave portion 62 of the stator 61 and then is guided to the next concave portion 62. He is repeatedly crushed and crushed. After repeatedly receiving this crushing action, the concave portions 62 of the stator 61
While entering the swirling air flowing toward the outlet while swirling at high speed inside, the centrifugal classification action is performed by the swirling motion about the center of curvature of the concave portion 62, and the coarse particles are thrown out from the concave portion 62. Fines are carried out of the recess 62 toward the discharge port to prevent over-crushing.

[0003]

The toner particles used for image formation are required to have a smaller particle size and a spherical shape due to the demand for higher image quality in the future. In addition, toner particles having a small particle size and a spherical shape are required. The mechanical pulverizer disclosed in Japanese Patent Application Laid-Open No. 5-269393 is capable of pulverization with a small particle size to some extent, and has a higher energy efficiency than a pneumatic jet pulverizer known as a toner pulverizer. Well,
It is said that the toner particles are also excellent in spherical shape. However, in order to satisfy the demand for higher image quality, there is a demand for improved sphericity of the pulverized toner particles.

SUMMARY OF THE INVENTION The present invention has been made to satisfy such a demand, and aims at reducing the size of crushed particles and further improving the sphericity, and at the same time preventing the abrasion of the rotor and stator wall surfaces and efficiently crushing. It is an object of the present invention to provide a pulverizing device and a toner manufacturing device capable of performing the same and a toner manufactured thereby.

[0005]

According to the present invention, there is provided a crushing apparatus comprising: a rotor in which a large number of concave and convex portions parallel to a generating line are continuously formed in a circumferential direction on an outer surface supported by a rotating shaft; In a pulverizer that finely pulverizes an object to be pulverized between the stator and a plurality of uneven portions parallel to the generatrix on the inner surface and arranged in a circumferential direction, the rotation is upstream of the concave portion of the stator. 150 degrees to 180 degrees of side wall surface to inner surface
And the downstream side wall surface in the rotation direction is formed at an angle of 90 to 145 degrees with respect to the inner surface.

It is desirable that the stator be removably attached to an inner peripheral surface of the casing, which is formed by a convex portion protruding toward the axis between the inlet and the outlet for charging the material to be ground.

[0007] A spacer for adjusting the gap between the stator and the rotor may be provided between the casing and the stator.

Further, the rotor or the stator may be provided with one or a plurality of weirs serving as resistance of an air flow flowing through a gap between the stator and the rotor.

[0009] It is desirable that the surfaces of the stator and the rotor are lined with titanium and hardened.

[0010] An apparatus for producing a toner according to the present invention includes any one of the pulverizing apparatuses described above.

It is desirable that the outlet of the casing of the pulverizing device be set at a temperature lower than the softening point of the resin forming the toner, or that a cooling jacket be provided on the outer peripheral surface of the casing of the pulverizing device.

[0012] A toner according to the present invention is manufactured by the above-described toner manufacturing apparatus.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A pulverizing device provided in a toner manufacturing apparatus according to the present invention has a gap between a rotor supported by a rotating shaft rotatably mounted on both side walls of a casing and the rotor. And a stator detachably attached to the casing. One end of the casing has a charging port, and the other end has a discharging port sucked by a blower. The rotor has a large number of concavities and convexities parallel to the generatrix on the outer surface formed continuously in the circumferential direction, and also has a number of irregularities parallel to the generatrix on the inner surface of the stator facing the rotor. The rotation-direction upstream side wall surface of the concave portion provided on the inner surface of the stator is formed in a planar shape with an angle formed between the inner surface and the inner surface in the range of 150 to 180 degrees, and the rotation-direction downstream side wall surface forms an angle with the inner surface. Are formed in a plane from 90 degrees to 145 degrees.

The rotator supported by the rotating shaft is rotated at a high speed by this crusher, and is sucked by a blower from a discharge port, so that a gap between the rotating rotor and the stator is discharged from an input port. An airflow is flowing to the outlet. In this state, an object to be ground, which is a raw material of the toner, is supplied from the feeder. The material to be pulverized is subjected to a pulverizing action when flowing through the gap and is pulverized and discharged from the outlet. When the object to be crushed is crushed, the object to be crushed flows by the airflow flowing through the gap along the upstream side wall surface in the rotation direction of the recess of the stator and collides with the downstream side wall surface in the rotation direction. This collision has the effect of rounding the corners of the crushed object. In addition, since the crushed object colliding with the downstream wall in the rotation direction has a large angle with the inner surface and sharply stands with respect to the inner surface, the crushed object is located next to the stator. It is difficult to be guided to the concave portion, and it may be reflected on the upstream side wall surface side in the rotation direction and collide again with the same downstream side wall surface in the rotation direction, thereby improving the circularity of the material to be ground and producing a toner with a high circularity. be able to.

[0015]

FIG. 1 is a block diagram of a pulverizer according to an embodiment of the present invention. As shown in the figure, the crushing device 1 is provided with a gap 5 between a rotor 4 supported by a rotating shaft 3 rotatably mounted on both side walls of a casing 2 and the rotor 4, and It has a stator 6 that is detachably attached. One end of the casing 2 has an inlet 7 and the other end has an outlet 8 sucked by a blower (not shown). A stator is provided between the inlet 7 and the outlet 8. 6 is provided with a convex portion. As shown in the schematic diagram of FIG. 2, the rotor 4 is formed with a large number of concavities and convexities parallel to the generatrix of the outer surface in the circumferential direction, and also on the inner surface of the stator 6 facing the rotor 4. It has many irregularities parallel to the generatrix. The rotation angle upstream side wall surface 11 of the recess 10 provided on the inner surface 9 of the stator 6 has an angle α with the inner surface 9 of 150 to 180 degrees.
Degree, and is formed in a planar shape in the range of
Is formed in a plane shape with an angle β between the inner surface 9 and 90 degrees to 145 degrees.

The rotator 4 supported on the rotating shaft is rotated at a high speed by the crushing device 1 having the above-described structure, and the rotator 4 and the stator 6 are rotated by suction from the discharge port 8 with a blower. An airflow flowing from the inlet 7 to the outlet 8 is generated in the gap 5. In this state, the material 13 to be ground is fed from a feeder (not shown). Pulverized object 1
3 flows through the gap 5 and is pulverized by a pulverizing action and discharged from the discharge port 8. When the crushed object 13 is crushed, the crushed object 13 flows along the rotation-direction upstream side wall surface 11 of the recess 10 of the stator 6 and collides with the rotation-direction downstream side wall surface 12 due to the airflow flowing through the gap 5. This collision has the effect of rounding the corners of the crushed object 13. In addition, since the angle β between the downstream side wall surface 12 in the rotation direction and the object 13 colliding with the downstream side wall surface 12 in the rotation direction makes a large angle β with the inner surface 9 and stands sharply with respect to the inner surface 9, the stator 6 Is difficult to be guided to the next concave portion 10, and may be reflected on the upstream side wall surface 11 in the rotational direction and collide again with the downstream side wall surface 12 in the same rotational direction. Can be.

In order to efficiently impinge the object 13 on the downstream side wall surface 12 in the rotation direction and thereby increase the circularity, the angle α between the rotation side upstream side wall surface 11 of the recess 10 and the inner surface 9 is determined. It is preferable to set the angle β between the downstream side wall surface 12 and the inner surface 9 in the rotation direction in the range of 90 to 145 degrees. The shape of the concave portion 10 formed by the rotation-direction upstream side wall surface 11 and the rotation-direction downstream side wall surface 12 is not particularly limited, but an arc-shaped apex angle is particularly preferable.

When the surfaces of the stator 6 and the rotor 4 are subjected to a lining treatment with titanium in order to prevent wear of the stator 6 and the rotor 4 which are crushed by collision of the object 13 to be ground. good. Thus, by lining the surface of the stator 6 and the surface of the rotor 4 with titanium, the durability against abrasion could be improved about twice as compared with the case without the lining treatment.

Further, the stator 6 having the concave portion 10 is attached to the inner peripheral surface of the casing 2 having a convex portion protruding toward the axial center between the inlet 7 and the outlet 8 of the casing 2 so that the casing 2 The attachment and detachment of the stator 6 can be facilitated, and the switching time when switching the stator 6 having different angles α and β depending on the particle size to be crushed can be reduced.

In the above-described embodiment, the case where the stator 6 is directly attached to the casing 2 has been described. However, as shown in FIG. 3, a spacer 14 is provided between the casing 2 and the stator 6, and according to the particle size to be pulverized. It is preferable to adjust the gap 5 between the rotor 4 and the stator 6 by replacing the spacer 14. Thus, by adjusting the gap 5 through which the material 13 to be crushed flows by the spacers 14 and changing the flow rate of the material to be crushed 14, it is possible to reduce the particle size and to efficiently crush the material.

Further, as shown in FIG. 4, one or more ring-shaped weirs 15 are provided on the rotor 4 or, as shown in FIG. By providing resistance to the flowing airflow, coarse particles can be prevented from jumping into the discharge port 8 side, and small particles having a uniform particle size can be obtained.

Further, when the toner used in the electrophotographic image forming apparatus is manufactured by the crushing apparatus 1, the temperature of the outlet 8 is adjusted by adjusting the air volume of a blower sucking the outlet 8 side. It is preferable to set the temperature to be equal to or lower than the softening point temperature of the resin. As described above, by setting the temperature of the discharge port 8 to be equal to or lower than the resin softening point temperature and controlling the temperature inside the crushing apparatus 1, it is possible to take measures against the melt.

As shown in FIG. 6, a cooling jacket 17 is provided on the outer surface of the casing 2 to cool the inside of the crushing device 1, so that the crushing efficiency can be further improved and the inside of the crushing device 1 can be improved. , And the toner having a high circularity can be manufactured with a uniform particle size. By developing a latent image formed by electrophotography using this toner, a high-quality image can be formed stably.

Further, as shown in FIG. 7, the outlet 8 and the inlet 7 of the crusher 1 are connected to a classifier 18 to
And a classifier 18 to form a closed circuit,
3 can be pulverized into fine particles having a constant particle size.

[Specific Examples] For example, a mixture having the following composition is melt-kneaded, cooled, coarsely pulverized, and has an average particle diameter of 400 μm.
m was obtained. This coarsely pulverized material was pulverized by the pulverizer 1. Styrene-acrylic copolymer 100 parts by weight Carbon black 10 parts by weight Polypropylene 5 parts by weight Zinc salicylate 2 parts by weight The particle size of the pulverized product is measured by a Coulter counter, and the circularity is measured by a flow type particle image analyzer. Used and measured.

[Specific Example 1] In the stator 6, the angle α between the upstream side wall surface 11 in the rotation direction and the inner surface 9 is 160 degrees, and the angle β between the downstream side wall surface 12 in the rotation direction and the inner surface 9 is β.
Using a crusher 1 having a rotor 10 having a recess 10 of 110 degrees, a peripheral speed of the rotor 4 set to 135 m / s, and a gap 5 between the rotor 4 and the stator 6 set to 1.5 mm. Crushed. At that time, the feed rate was 9.00 kg / h with respect to the target having an average particle diameter of 8.0 μm. As a result, the volume average particle size was 7.8 μm, and the average circularity was 0.950.
Therefore, the circularity could be improved. Further, by providing the casing 2 with the convex portion, the switching time for removing the stator 6 from the casing 2 and cleaning it can be reduced by about 25% compared to the case where the casing 2 is not provided with the convex portion.

[Specific Example 2] As shown in FIG. 3, a spacer 14 is provided, and a gap 5 between the rotor 4 and the stator 6 is set to 1.0 m.
m, and a coarsely pulverized product having the same composition as described above was pulverized under the same conditions as in Example 1. Average particle size 8.0μ at that time
The feed rate was 8.80 kg / h with respect to the target of m. As a result of this pulverizing treatment, the volume average particle size was 7.6 μm, and the average circularity was 0.955, and the circularity could be further improved.

[Specific Example 3] As shown in FIG. 4, one weir 15 was provided on the rotor 4 and the other parts were pulverized under the same conditions as in the specific example 1. At that time, the feed rate was 8.75 kg / h with respect to the target having an average particle diameter of 8.0 μm. As a result, the volume average particle size was 7.7 μm, and the average circularity was 0.4 μm.
953. The rotor 4 was provided with two weirs 15 and pulverized under the above conditions. As a result, the volume average particle size was 7.6 μm.
m, the average circularity was 0.955, and the circularity could be further improved by making the particle size more uniform.

[Specific Example 4] As shown in FIG. 5, one weir 16 was provided on the stator 6 and the other parts were subjected to the pulverizing process under the same conditions as in the specific example 1. At that time, the feed rate was 8.00 kg / h with respect to the target having an average particle diameter of 8.0 μm. As a result, the volume average particle size was 7.7 μm, and the average circularity was 0.4 μm.
953. Also, two weirs 16 are provided on the stator 6,
As a result of performing the pulverization process under the above conditions, the volume average particle size was 7.
At 6 μm, the average circularity was 0.955, and the circularity could be further improved by making the particle size more uniform.

[Specific Example 5] The temperature of the discharge port 8 is set to be equal to or lower than the softening point temperature of the resin forming the toner by adjusting the air volume of the blower sucking the discharge port 8 side. And a pulverizing treatment was performed. The feed rate is 8.00 kg / h with respect to the target having an average particle diameter of 8.0 μm at that time.
Met. As a result, the volume average particle size was 7.8 μm, and the average circularity was 0.950. As shown in FIG. 6, a cooling jacket 17 is provided on the outer surface of the casing 2 and the pulverizing process is performed under the above conditions while cooling the inside of the pulverizing device 1. As a result, the same result as described above can be obtained. Was.

[Specific Example 6] As shown in FIG. 7, a closed circuit was constituted by the pulverizing apparatus 1 and the classifier 18, and the pulverizing treatment was performed under the same conditions as in the specific example 1. Average particle size 8.0μ at that time
The feed rate was 8.00 kg / h for the aim of m. As a result, the volume average particle size was 7.8 μm, and the average circularity was 0.950. Further, the coarse powder content (% by weight) of 16 μm or more was 0% by weight, and a narrow particle size distribution could be obtained.

COMPARATIVE EXAMPLE A coarsely pulverized product having the same composition as in Example 1 was rotated using a mechanical pulverizer in which the concave portions of the rotor 4 and the stator 6 were formed in arcs as shown in FIG. Child 4
Was set to 135 m / s, and the gap 5 between the rotor 4 and the stator 6 was set to 1.5 mm to perform a pulverization process. The feed amount was 9.00 with respect to the target having an average particle diameter of 8.0 μm at that time.
kg / h. As a result, the volume average particle size was 7.8 μm.
m and the average circularity was 0.940.

[0033]

As described above, according to the present invention, the side wall surface in the rotational direction of the recess of the stator is set to 150
Degrees to 180 degrees, and the downstream side wall surface in the rotation direction is formed at 90 degrees to 145 degrees with respect to the inner surface. Collisions can be made, and the corners of the object can be rounded to improve the circularity of the object.

Further, the stator is removably mounted on an inner peripheral surface having a convex portion protruding toward the axis between the inlet and the outlet for charging the material to be ground in the casing. Can be easily attached to and detached from the casing, and the switching time when the stator is removed from the casing for cleaning can be shortened to improve the working efficiency.

Further, a spacer for adjusting the gap between the stator and the rotor is provided between the casing and the stator, and the gap is adjusted by the particle size to vary the speed of the airflow flowing through the gap, thereby forming the pulverized material. It is possible to reduce the particle size of the product and to perform efficient pulverization.

Further, by providing one or a plurality of weirs on the rotor or the stator, which serve as resistance to the airflow flowing through the gap between the stator and the rotor, coarse particles can be prevented from entering the outlet of the pulverizer. Thus, a small particle size and a uniform particle size can be achieved.

Further, by hardening the surfaces of the stator and the rotor, wear of the stator and the rotor can be prevented, and the stator and the rotor can be used stably for a long period of time.

Further, by using this pulverizing apparatus in a toner manufacturing apparatus, a toner having a uniform particle diameter and a high circularity can be manufactured.

Further, the outlet of the casing of the crushing device is set to a temperature lower than the softening point of the resin forming the toner, or a cooling jacket is provided on the outer peripheral surface of the casing of the crushing device to cool the inside of the crushing device. In addition, the pulverization efficiency can be further improved, and a measure against the melt inside the pulverization device can be reliably performed, so that a toner having a high circularity and a uniform particle size can be produced.

By developing a latent image formed by an electrophotographic method using this toner, a high quality image can be formed stably.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a crusher according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing the shapes of an outer surface of a rotor and an inner surface of a stator of the embodiment.

FIG. 3 is a configuration diagram of a second embodiment.

FIG. 4 is a configuration diagram of a third embodiment.

FIG. 5 is a configuration diagram of a fourth embodiment.

FIG. 6 is a configuration diagram of a fifth embodiment.

FIG. 7 is a configuration diagram of a sixth embodiment.

FIG. 8 is a configuration diagram of a conventional rotor and stator.

FIG. 9 is a schematic diagram showing shapes of an outer surface of a rotor and an inner surface of a stator of a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1; Crushing apparatus, 2; Casing, 3; Rotating shaft, 4; Rotor, 5; Gap, 6; Stator, 7;
9; inner surface of stator; 10; concave portion; 11; upstream side wall surface in rotation direction; 12; downstream side wall surface in rotation direction.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Riki Shimizu 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Eiji Sugisawa 1-3-6 Nakamagome, Ota-ku, Tokyo Stock Ricoh Company (72) Inventor Kazuyoshi Morii 1-3-6 Nakamagome, Ota-ku, Tokyo F-term in Ricoh Company (reference) 2H005 AB04 EA03 4D065 AA07 EB20 ED04 ED14 ED31 EE02 EE19 EE12 EE19

Claims (9)

[Claims] A rotor having a plurality of concave and convex portions parallel to the generatrix on an outer surface supported by a rotating shaft and arranged in a circumferential direction; a rotor disposed at a minute interval outside the rotor; In a pulverizing device for finely pulverizing an object to be pulverized between a stator having a large number of concave and convex portions parallel to a bus line in a circumferential direction, an upstream side wall surface in a rotating direction of a concave portion of the stator is set at 150 degrees to an inner surface. A crushing device, wherein the crushing device is formed at an angle of 180 to 180 degrees, and the downstream side wall surface in the rotation direction is formed at an angle of 90 to 145 degrees with respect to the inner surface. 2. The stator according to claim 1, wherein the stator is detachably attached to an inner peripheral surface of the casing, which is formed with a convex portion protruding toward an axial center between an inlet and an outlet for charging the material to be ground. A crushing device as described. 3. A spacer is provided between the casing and the stator to adjust a gap between the stator and the rotor.
Or the crushing device according to 2. 4. The crusher according to claim 1, wherein the rotor or the stator is provided with one or a plurality of weirs that serve as resistance of an airflow flowing through a gap between the stator and the rotor. 5. The pulverizing apparatus according to claim 1, wherein the surfaces of the stator and the rotor are hardened. 6. An apparatus for producing a toner, comprising the pulverizing apparatus according to claim 1. 7. The toner production apparatus according to claim 6, wherein the outlet of the casing of the pulverizing device is set at a temperature not higher than the softening point of the resin forming the toner. 8. The toner manufacturing apparatus according to claim 6, wherein a cooling jacket is provided on an outer peripheral surface of a casing of the crushing device. 9. A toner manufactured by the toner manufacturing apparatus according to claim 6, 7, or 8.