JP4183388B2 - Grinding device, toner manufacturing device and toner - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention includes, for example, a pulverizing apparatus that produces fine powder such as dry toner that develops an electrostatic charge image in an electrophotographic system, an electrostatic recording system, an electrostatic printing system, and the like, a toner manufacturing apparatus, and a toner manufactured thereby, In particular, it relates to an improvement in the circularity of the crushed particles.
[0002]
[Prior art]
For example, a mechanical pulverizer that performs micron-order pulverization in order to produce toner for developing a latent image formed on a photoreceptor in an electrophotographic image forming apparatus is supported by a rotating shaft and has an outer surface. A rotor having a large number of irregularities along the generatrix, and a stator having a gap between the rotor and a plurality of irregularities along the generatrix on the inner surface. Then, while rotating the rotor, a solid object to be crushed is supplied from a supply port provided at one end of the outer surface of the stator, and the object to be crushed is predetermined between the rotating rotor and the stator. Grind to size. In order to efficiently pulverize the object to be crushed, for example, a mechanical pulverizer shown in Japanese Patent Laid-Open No. 5-269393 has an arched inner surface of a stator 61 facing the rotor 41 as shown in FIG. A recess 62 having a cross section is formed, and a swirl flow 63 having a rotation direction opposite to the rotation direction of the rotor 4 is generated inside the recess 62. As shown in the schematic diagram of FIG. 9, the object to be crushed supplied to the crushing apparatus collides with the downstream side wall surface 64 in the rotational direction of the concave portion 62 formed in the circular shape of the stator 61 and then led to the next concave portion 62. It is crushed by repeated collisions. After repeatedly receiving this crushing action, it enters into the air swirling flow that flows toward the outlet while swirling at high speed inside the recess 62 of the stator 61, and swirling motion around the center of curvature of the recess 62. Thus, the centrifugal classification action is performed, and coarse particles are thrown out from the concave portion 62, and fine particles are carried out from the concave portion 62 toward the discharge port to prevent over-pulverization.
[0003]
[Problems to be solved by the invention]
Toner particles used for image formation are indispensable to reduce the particle size and sphere due to the demand for further higher image quality in the future. There is a need for a spherical shape. The mechanical pulverizer disclosed in Japanese Patent Application Laid-Open No. 5-269393 is capable of pulverizing to a certain degree of particle size, and is more energy efficient than an airflow jet pulverizer known as a toner pulverizer. It is said that the toner particles are excellent in spheroidization. However, in order to satisfy the demand for higher image quality, there is a demand for improved sphericity of the pulverized toner particles.
[0004]
The present invention has been made to satisfy such a demand, and it is possible to reduce the particle size of the pulverized particles and improve the sphericity, and to prevent the wear of the wall surfaces of the rotor and the stator, thereby efficiently pulverizing. An object of the present invention is to provide a pulverizing apparatus, a toner manufacturing apparatus, and a toner manufactured thereby.
[0005]
[Means for Solving the Problems]
The pulverizing apparatus according to the present invention is supported by a rotating shaft, and on the outer surface, the upstream side wall surface in the rotational direction is formed at an obtuse angle with respect to the outer surface, and the downstream side wall surface in the rotational direction is formed at an acute angle with respect to the outer surface. The rotor is made continuous in the circumferential direction parallel to the busbars, and the outer surface of the rotor is arranged at a minute interval, and a number of unevenness portions parallel to the busbars are made continuous in the circumferential direction on the inner surface. A pulverizing apparatus that finely pulverizes and spheroidizes a material to be pulverized with a stator, and forms an upstream side wall surface in a rotation direction of a concave portion of the stator at an angle of 150 to 180 degrees with respect to an inner surface, The downstream wall surface in the rotation direction is formed at an angle of 90 to 145 degrees with respect to the inner surface, and the object to be crushed moves along the upstream wall surface in the rotation direction, and is moved a plurality of times on the same downstream wall surface in the rotation direction. It is characterized by a collision.
[0006]
It is desirable that the stator is detachably attached to an inner peripheral surface composed of a convex portion provided so as to protrude toward the axial center between the inlet and the outlet into which the object to be crushed is introduced.
[0008]
Further, one or a plurality of weirs may be provided on the rotor or the stator to serve as a resistance to the airflow flowing through the gap between the stator and the rotor.
[0010]
A toner manufacturing apparatus according to the present invention includes any one of the above-described pulverizing apparatuses.
[0011]
In addition, it is desirable that the discharge port of the casing of the pulverizer is set to be equal to or lower than the softening point temperature of the resin forming the toner, or a cooling jacket is provided on the outer peripheral surface of the casing of the pulverizer.
[0012]
The toner according to the present invention is manufactured by the toner manufacturing apparatus.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
The pulverizing apparatus provided in the toner manufacturing apparatus of the present invention is detachable from the casing with a gap between the rotor supported by a rotating shaft rotatably attached to both side walls of the casing and the rotor. Having a stator attached to. One end of the casing has an inlet, and the other end has an outlet that is sucked by a blower. In the rotor, a large number of irregularities parallel to the generatrix on the outer surface are continuously formed in the circumferential direction, and the inner surface facing the rotor of the stator also has a large number of irregularities parallel to the generatrix. The upstream side wall surface in the rotational direction of the recess provided on the inner surface of the stator is formed in a planar shape with an angle between the inner surface and 150 ° to 180 °, and the downstream side wall surface in the rotational direction is an angle formed with the inner surface. Is formed in a planar shape in the range of 90 to 145 degrees.
[0014]
By rotating the rotor supported by the rotating shaft at high speed in this crusher and sucking it from the discharge port with a blower, the gap between the rotating rotor and the stator flows from the input port to the discharge port. Airflow is generated. In this state, a material to be crushed as a raw material for the toner is fed from the feeder. The charged material to be pulverized is pulverized and discharged from the discharge port when flowing through the gap. When the object to be pulverized is pulverized, the object to be pulverized flows along the upstream side wall surface in the rotation direction of the concave portion of the stator and collides with the downstream side wall surface in the rotation direction by the airflow flowing through the gap. This collision has the effect of rounding the corners of the object to be crushed. In addition, the downstream side wall surface in the rotational direction where the object colliding with the downstream wall surface in the rotation direction collides with the inner surface is large and stands sharply with respect to the inner surface. It becomes difficult to be guided to the concave portion, and may be reflected on the upstream side wall surface side in the rotational direction and collide with the same downstream side wall surface in the rotational direction again, thereby improving the circularity of the object to be crushed and producing toner with high circularity. be able to.
[0015]
【Example】
FIG. 1 is a block diagram of a pulverizing apparatus according to an embodiment of the present invention. As shown in the figure, the crushing device 1 is provided in the casing 2 by providing a gap 5 between the rotor 4 supported by a rotating shaft 3 rotatably attached to both side walls of the casing 2 and the rotor 4. The stator 6 is detachably attached. The casing 2 has an inlet 7 at one end, and an outlet 8 that is sucked by a blower (not shown) at the other end. A stator is disposed between the inlet 7 and the outlet 8. 6 has a convex portion to which 6 is attached. On the outer surface of the rotor 4, as shown in the schematic view of FIG. 2, the upstream wall surface in the rotational direction is formed at an obtuse angle with respect to the outer surface, and the downstream wall surface in the rotational direction is formed at an acute angle with respect to the outer surface. A large number of uneven portions are continuously formed in the circumferential direction in parallel with the bus bar, and the inner surface of the stator 6 facing the rotor 4 has a large number of uneven portions parallel to the bus line . The rotation direction upstream side wall surface 11 of the recess 10 provided on the inner surface 9 of the stator 6 is formed in a planar shape with an angle α formed with the inner surface 9 in the range of 150 degrees to 180 degrees, and the rotation direction downstream side wall surface 12. Is formed in a planar shape with an angle β formed with the inner surface 9 in the range of 90 to 145 degrees.
[0016]
By rotating the rotor 4 supported on the rotating shaft at a high speed by the crushing apparatus 1 configured as described above and sucking it from the discharge port 8 with a blower, the rotor 4 is rotated between the rotating rotor 4 and the stator 6. In the gap 5, an airflow flowing from the inlet 7 to the outlet 8 is generated. In this state, the material 13 to be crushed is fed from a feeder (not shown). The charged object 13 is pulverized and discharged from the outlet 8 when it flows through the gap 5. When this object 13 is pulverized, the object 13 flows along the upstream side wall surface 11 in the rotational direction of the recess 10 of the stator 6 by the airflow flowing through the gap 5 and collides with the downstream side wall surface 12 in the rotational direction. This collision has the effect of rounding the corners of the object 13 to be crushed. Further, the rotation direction downstream side wall surface 12 on which the object 13 colliding with the rotation direction downstream side wall surface 12 collides has a large angle β with the inner surface 9 and stands sharply with respect to the inner surface 9. To the next concave portion 10, and may be reflected to the upstream side wall surface 11 side in the rotational direction and collide with the same downstream side wall surface 12 in the rotational direction again, thereby improving the circularity of the object 13 to be crushed. Can do.
[0017]
In this way, in order to efficiently collide the object 13 with the downstream side wall surface 12 in the rotational direction and increase the circularity, the angle α formed between the upstream side wall surface 11 in the rotational direction of the recess 10 and the inner surface 9 is set to 150 degrees. It is preferable that the range is 180 degrees, and the angle β formed between the downstream side wall surface 12 in the rotation direction and the inner surface 9 is in the range of 90 degrees to 145 degrees. The shape of the recess 10 formed by the upstream wall surface 11 in the rotational direction and the downstream wall surface 12 in the rotational direction is not particularly limited, but an apex angle is particularly preferable.
[0018]
In addition, in order to prevent wear of the stator 6 and the rotor 4 that collide with the object 13 to be crushed, the surface of the stator 6 and the surface of the rotor 4 may be lined with titanium. Thus, by lining the surface of the stator 6 and the surface of the rotor 4 with titanium, it was possible to improve the durability against wear by about twice as compared with the case where the lining treatment was not performed.
[0019]
Furthermore, the stator 6 having the recess 10 is attached to an inner peripheral surface having a convex portion provided so as to protrude toward the axial center between the input port 7 and the discharge port 8 of the casing 2. Can be easily attached and detached, and the switching time when switching the stator 6 having different angles α and β according to the particle size to be crushed can be shortened.
[0020]
Although the said Example demonstrated the case where the stator 6 was directly attached to the casing 2, as shown in FIG. 3, the spacer 14 was provided between the casing 2 and the stator 6, and the spacer 14 was changed according to the particle size to grind | pulverize. It is preferable to adjust the gap 5 between the rotor 4 and the stator 6 by exchanging them. Thus, by adjusting the gap 5 through which the object to be pulverized 13 flows by the spacer 14 and changing the flow rate of the object to be pulverized 14, the particle size can be reduced and the pulverization can be efficiently performed.
[0021]
Also, as shown in FIG. 4, one or more ring-shaped weirs 15 are provided on the rotor 4, or as shown in FIG. 5, a ring-shaped weir 16 is provided on the stator 6, so that the airflow flowing through the gap 5 By giving resistance to the coarse particles, it is possible to prevent coarse particles from jumping to the discharge port 8 side, and small particles having a uniform particle diameter can be obtained.
[0022]
Further, when the toner used in the electrophotographic image forming apparatus is manufactured by the pulverizing apparatus 1, the air volume of the blower that sucks the discharge port 8 side is adjusted, and the temperature of the discharge port 8 is adjusted to soften the resin that forms the toner. It is good to set below the point temperature. Thus, the melt countermeasure can be taken 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 pulverizer 1.
[0023]
In addition, as shown in FIG. 6, by providing a cooling jacket 17 on the outer surface of the casing 2 and cooling the inside of the pulverizing apparatus 1, the pulverization efficiency can be further improved and measures against melt in the pulverizing apparatus 1 are provided. Thus, a toner having a high circularity can be produced with a uniform particle size. By developing a latent image formed by electrophotography using this toner, a high-quality image can be stably formed.
[0024]
Further, as shown in FIG. 7, the discharge port 8 and the input port 7 of the pulverizing apparatus 1 are connected to a classifier 18, and the pulverizing apparatus 1 and the classifier 18 constitute a closed circuit so that the object to be crushed 13 is fixed. It can be pulverized into fine particles having a particle size.
[0025]
[Specific Example] For example, a mixture having the following composition was melt-kneaded and cooled, and then coarsely pulverized to obtain a coarsely pulverized product having an average particle size of around 400 μm. This coarsely pulverized product 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 pulverized product was measured with a Coulter counter, and the circularity was determined by using a flow particle image analyzer. Used and measured.
[0026]
[Specific Example 1] As the stator 6, the angle α formed between the upstream wall surface 11 in the rotation direction and the inner surface 9 is 160 degrees, and the angle β formed between the downstream wall surface 12 in the rotation direction and the inner surface 9 is 110 degrees. The stator 6 having the recess 10 was used, and the grinding was performed using the grinding device 1 in which the circumferential speed of the rotor 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. 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 diameter was 7.8 μm, the average circularity was 0.950, and the circularity could be improved. In addition, by providing the casing 2 with the convex portion, the switching time when the stator 6 is removed from the casing 2 for cleaning can be shortened by about 25% compared to the case where the casing 2 is not provided with the convex portion.
[0027]
[Specific Example 2] As shown in FIG. 3, a spacer 14 is provided, the gap 5 between the rotor 4 and the stator 6 is set to 1.0 mm, and a coarsely pulverized product having the same composition as that described above is the same as in Specific Example 1. And crushed with. The feed rate was 8.80 kg / h with respect to the target having an average particle diameter of 8.0 μm. As a result of this pulverization treatment, the volume average particle diameter was 7.6 μm, the average circularity was 0.955, and the circularity could be further improved.
[0028]
[Specific Example 3] As shown in FIG. 4, the rotor 4 was provided with one weir 15, and the pulverization was performed under the same conditions as in Specific Example 1. 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 0.953. In addition, as a result of providing two weirs 15 on the rotor 4 and pulverizing under the above conditions, the volume average particle size is 7.6 μm and the average circularity is 0.955. It was possible to improve more.
[0029]
[Specific Example 4] As shown in FIG. 5, the stator 6 was provided with one weir 16, and the others were pulverized under the same conditions as in Specific Example 1. 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 0.953. Further, two weirs 16 were provided on the stator 6 and pulverization was performed under the above conditions. As a result, the volume average particle size was 7.6 μm and the average circularity was 0.955. The degree could be improved more.
[0030]
[Specific Example 5] The flow rate of the blower that sucks the discharge port 8 side is adjusted so that 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. Processed. 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 7.8 μm and the average circularity was 0.950. Further, as shown in FIG. 6, a cooling jacket 17 is provided on the outer surface of the casing 2, and the pulverization process is performed under the above conditions while cooling the inside of the pulverizer 1, so that the same result as above can be obtained. It was.
[0031]
[Specific Example 6] As shown in FIG. 7, the pulverization apparatus 1 and the classifier 18 constitute a closed circuit, and the pulverization process was performed under the same conditions as in Specific Example 1. At that time, the feed rate was 8.00 kg / h with the aim of 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. A coarse particle size distribution with a coarse powder content (wt%) of 16 μm or more was 0 wt% could be obtained.
[0032]
[Comparative Example] As shown in FIG. 9, a coarsely pulverized product having the same composition as that of Example 1 was used, and a mechanical pulverizer in which concave portions of the rotor 4 and the stator 6 were formed by arcs was used. Grinding was performed with the peripheral speed set to 135 m / s and the gap 5 between the rotor 4 and the stator 6 set to 1.5 mm. The feed rate was 9.00 kg / h with respect to the target having an average particle size of 8.0 μm. As a result, the volume average particle diameter was 7.8 μm and the average circularity was 0.940.
[0033]
【The invention's effect】
As described above, according to the present invention, the outer surface of the rotor has an upstream side wall surface in the rotational direction formed at an obtuse angle with respect to the outer surface, and a number of irregularities in which the downstream side wall surface in the rotational direction is formed at an acute angle with respect to the outer surface. Are formed continuously in the circumferential direction in parallel with the generatrix, the upstream side wall surface in the rotational direction of the concave portion of the stator is formed at 150 to 180 degrees with respect to the inner surface, and the downstream side wall surface in the rotational direction is formed with respect to the inner surface. 90 to 145 degrees, the object to be pulverized can collide with the downstream side wall surface in the rotational direction multiple times while flowing along the upstream side wall surface in the rotational direction. The circularity of the pulverized product can be improved.
[0034]
In addition, the stator can be attached to the casing by detachably attaching the stator to an inner peripheral surface having a convex portion provided so as to protrude from the inlet and outlet of the casing to which the object to be crushed is charged. On the other hand, it can be easily attached and detached, and the switching time when the stator is removed from the casing for cleaning can be shortened to improve work efficiency.
[0035]
Furthermore, a spacer for adjusting the gap between the stator and the rotor is provided between the casing and the stator, and the speed of the airflow flowing through the gap is varied by adjusting the gap according to the particle size, thereby reducing the size of the pulverized material to be formed. The particle size can be reduced and efficient grinding can be performed.
[0036]
In addition, by providing one or more weirs that provide resistance to the airflow flowing through the gap between the stator and the rotor on the rotor or the stator, it is possible to prevent the coarse particles from entering the outlet side of the pulverizer. It is possible to achieve a small particle size and uniform particle size.
[0038]
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.
[0039]
Furthermore, the crushing efficiency of the crusher can be reduced by lowering the discharge port of the crusher casing below the softening point of the resin forming the toner, or by providing a cooling jacket on the outer peripheral surface of the crusher casing to cool the inside of the crusher. As a result, it is possible to reliably take measures against melting in the pulverizing apparatus, and to manufacture a toner having a high circularity with a uniform particle size.
[0040]
Further, by developing a latent image formed by electrophotography using this toner, a high-quality image can be stably formed.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a pulverizing apparatus according to an embodiment of the present invention.
FIG. 2 is a schematic diagram showing the shapes of the outer surface of the rotor and the inner surface of the stator in the above 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 rotor and a stator of a conventional example.
FIG. 9 is a schematic diagram showing the shapes of the outer surface of the rotor and the inner surface of the stator in the conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1; Grinding device, 2; Casing, 3; Rotating shaft, 4; Rotor, 5;
6; stator, 7; inlet, 8; outlet, 9; inner surface of stator,
10; concave portion, 11; upstream side wall surface in the rotational direction, 12; downstream side wall surface in the rotational direction.

Claims (7)

Supported by the rotating shaft, on the outer surface, the upstream side wall surface in the rotational direction is formed at an obtuse angle with respect to the outer surface, and a number of concave and convex portions formed with the downstream side wall surface in the rotational direction at an acute angle with respect to the outer surface are parallel to the generatrix. Grinding between a rotor that is continuous in the circumferential direction and a stator that is arranged on the outer surface of the rotor with a small interval and that has a large number of irregularities parallel to the generatrix on the inner surface. A pulverizing device that pulverizes and spheroidizes through an object,
The rotation direction upstream side wall surface of the concave portion of the stator is formed at an angle of 150 ° to 180 ° with respect to the inner surface, and the rotation direction downstream side wall surface is formed at an angle of 90 ° to 145 ° with respect to the inner surface. The pulverized apparatus moves along the upstream side wall surface in the rotational direction and collides with the same downstream side wall surface in the rotational direction a plurality of times.   2. The pulverizing apparatus according to claim 1, wherein the stator is detachably attached to an inner peripheral surface formed of a convex portion provided so as to protrude toward an axial center between an inlet and an outlet into which an object to be crushed is input. The crushing apparatus according to claim 1 or 2, wherein the rotor or the stator is provided with one or a plurality of weirs which serve as resistance of the airflow flowing through the gap between the stator and the rotor. A toner manufacturing apparatus comprising the pulverizing apparatus according to claim 1. The toner manufacturing apparatus according to claim 4, wherein a discharge port of a casing of the pulverizing apparatus is set to be equal to or lower than a softening point temperature of a resin forming the toner. The toner manufacturing apparatus according to claim 4, wherein a cooling jacket is provided on an outer peripheral surface of a casing of the pulverizer. A toner manufactured by the toner manufacturing apparatus according to claim 4.

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