JPS61249711A - Heat treatment device - Google Patents

Abstract

PURPOSE:To contrive to obtain at high yield granule and powder in small and uniform diameter by providing a rotating nozzle exhausting dispersion air stream and a dispersion air stream feeding mechanism feeding diffusion air stream inside of said rotating nozzle. CONSTITUTION:The mechanism 29 feeding air stream for diffusion is composed of the diffusion air stream nozzles 30 provided on the peripheral wall of a rotating nozzle 28 so as to be connected to the inside of said nozzle 28, and the diffusion air stream feeding part feeding the diffusion air stream to said nozzles 30. The diffusion air stream nozzles 30 are arranged in the positions almost symmetrical in relation with the axial direction of the rotating nozzle 28. These diffusion air stream nozzles 30 are arranged in such a manner that the diffusion air streams are, for instance, supplied in the directions crossing mutually downward obliqualy in relation to the axis of the rotating nozzle 28 inside of said nozzle 28. From the opening of the rotating nozzle 28, the dispersion air stream of powder and granule is exhausted downward while swirling at the state where the thickness D of the air stream layer of an empty cone shape is increased. Consequently, the space density of the powder and granule in the dispersion air stream is decreased, whereby the powder and granule are fully dispersed in low density.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a heat treatment apparatus used for heat treating powder or granules to obtain particulate powder in a desired form. . More specifically, a diffusion airflow supply mechanism includes a swirling nozzle that swirls and discharges an airflow in which powder particles mainly composed of thermoplastic resin or the like are dispersed, and supplies a diffusion airflow inside the swirling nozzle. By providing a heating mechanism that heats the swirling airflow discharged from the swirling nozzle, coarsening of particles due to adhesion can be prevented, and a high yield of small and uniformly sized powder particles can be achieved. The present invention relates to a heat treatment apparatus that can obtain heat treatment at a high rate.

[Prior art]

For example, in a dry type electrophotographic copying machine, powder particles called toner are used to develop and develop an electrostatic latent image formed on a photoreceptor. Such a toner is usually manufactured by heat-treating a powder or granular material containing a thermoplastic resin as a main component and molding it into powder particles having a desired shape, that is, a desired particle size and shape.

Conventionally, heat treatment equipment used in such a heat treatment process for powder and granules has been used to disperse powder and granules mainly composed of thermoplastic resin into a jet stream of pressurized hot gas from the outside or in directions that intersect with each other. 2. Description of the Related Art A heat treatment apparatus is known that is configured to perform heat treatment on the powder or granular material by blowing an air flow into it.

[Problem that the invention seeks to solve]

However, in an apparatus with such a configuration, it is difficult to uniformly mix the dispersion airflow of powder and granules with the jet flow of pressurized hot gas, which results in uneven heat treatment and coarse particles due to aggregation. As a result, it is difficult to obtain small and uniformly sized powder particles with a high yield.

For this reason, by discharging the dispersion airflow of powder and granular material while swirling it from a swirling nozzle, a hollow cone-shaped swirling airflow is formed by the airflow, and a heated airflow is simultaneously generated from the outside of this hollow cone-shaped swirling airflow. A heat treatment apparatus has been proposed in which the heat treatment is performed by mixing the materials while rotating them in the same direction. According to the device having such a configuration, the dispersion airflow of the powder and the heated airflow are almost evenly mixed. However, the swirling airflow is concentrated near the inner wall of the swirling nozzle due to centrifugal force, When the layer becomes thinner and the amount of powder and granules supplied increases, the density of the powder and granules in the swirling airflow bed increases, which tends to cause the particles to stick together, resulting in the formation of coarse particles. It has points.

[Purpose of the invention]

The present invention has been made based on the above-mentioned circumstances, and its object is to be able to disperse powder and granules well at a small density, to suppress the generation of coarse particles, and as a result, to suppress the generation of coarse particles. It is an object of the present invention to provide a heat treatment apparatus capable of obtaining powder particles having a small diameter and uniform particle size at a high yield.

[Means for solving problems]

The heat treatment apparatus of the present invention is a heat treatment apparatus for heat-treating powder and granular materials in an air stream, and includes a swirling mechanism that swirls an airflow dispersing the powder and granules, and a swirling mechanism that heats the swirled dispersion airflow of the powder and granular materials. The heating mechanism is characterized in that the swirling mechanism includes a swirling nozzle that discharges a dispersed airflow, and a diffusion airflow supply mechanism that supplies a diffusion airflow to the inside of the swirling nozzle. .

According to such a device, the dispersion airflow of the powder and granules is disturbed and diffused by the diffusion airflow while swirling inside the rotating nozzle, so that the powder and granules are well dispersed with a small density. It will now be discharged from the rotating nozzle. Therefore, during the heat treatment, coarsening due to adhesion of the powder particles to each other is suppressed, and as a result, particles of small diameter and uniform particle size can be obtained at a high yield.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is an explanatory diagram showing an outline of an example of a heat treatment apparatus,
2 is a heat treatment container, 2 is a rotating mechanism, 3 is a heating mechanism, 4 is a cooling air supply mechanism, 5 is a cyclone, 6 is a dust collector, and 7 is an exhaust mechanism.

As shown enlarged in FIGS. 2 and 3, the turning mechanism 2 includes an ejector section 21 and a turning section 22, and the ejector section 21 has a compressed air flow inlet 23 and a powder supply port It consists of a mouth 24, a mixing chamber 25, and a throat portion 26. The swirling section 22 includes a swirling chamber 27, a swirling nozzle 28, and a diffusion air flow supply mechanism 29.

As shown enlarged in FIGS. 2 and 3, the diffusion air flow supply mechanism 29 includes a diffusion air flow nozzle 30 provided on the peripheral wall of the swirl nozzle 28 so as to communicate with the interior of the swirl nozzle 28, and It consists of a diffusion airflow supply section (not shown) that supplies diffusion airflow to the diffusion airflow nozzle 30. In this example, a total of four diffusion airflow nozzles 30 are arranged, and these four diffusion airflow nozzles L; The airflow nozzle 30 is arranged so that the diffusion airflow is supplied into the swirling nozzle 28 in a direction diagonally downward and intersecting the axis of the swirling nozzle 28, for example. The pressure of the diffusion airflow or the discharge direction of the diffusion airflow is not particularly limited and can be freely selected.

In addition, the heat treatment performance of the powder or granules, such as granulation degree, yield, particle size distribution, etc., is affected by the pressure of this diffusion airflow, the discharge direction of the diffusion airflow, and the number of diffusion airflow nozzles 30. When configuring a heat treatment device that can be used in the heat treatment process in the manufacturing process of toner used in electrophotographic copying machines, toner particles usually have a particle size of 6 to 6.
It is necessary that the particle powder has a small diameter within the range of 20 μm and the particle size is uniform, so the particle size of the obtained powder powder falls within the above range and the particle size is uniform within the range. It is preferable to select the pressure of the diffusion airflow, the discharge direction of the diffusion airflow, and the number of diffusion airflow nozzles 30 so that The temperature of this diffusion airflow is not particularly limited. Alternatively, instead of providing the diffusion airflow nozzle 30, an annular slit extending along the circumferential direction of the swirling nozzle 28 may be provided, and the diffusion airflow may be supplied into the swirling nozzle 28 through this slit. .

The heating mechanism 3 includes, for example, an air supply section 31 and an air supply section 31.
It consists of a heater part 32 that heats the airflow supplied from the heater part 32, and a heated airflow introducing part 33 that introduces the heated airflow from the heater part 32 into the container 1. This heated air flow introducing section 33
is provided with a rectifier 34, and the rectifier 34 directs the heated air flow toward the entire outer periphery of the opening of the swirl nozzle 28 so as to surround the dispersed airflow of powder and granules discharged from the opening of the swirl nozzle 28. Supplied.

In the swirling mechanism 2, when compressed airflow is introduced into the mixing chamber 25 from the compressed airflow inlet 23 and powder and granules are supplied into the mixing chamber 25 from the supply port 24, the high pressure in which the powder and granules are dispersed is generated. The airflow is introduced into the swirling chamber 27 through the throat portion 26, and the high-pressure dispersed airflow of powder and granules swirls within the swirling chamber 27, so that the pressure causes it to descend along the inner wall of the swirling nozzle 28. Become. However, the swirling airflow of the lever is
Because the flow is disturbed by colliding with the diffusion airflow supplied from the diffusion airflow nozzle 30 into the swirling nozzle 28, the swirling airflow that was flowing along the inner wall of the swirling nozzle 28 is directed to the inner side of the swirling nozzle 28. The rotating nozzle 2
It is discharged downward from the opening 8. On the other hand, when the heated airflow is supplied into the container 1 by the heating mechanism 3, the heated airflow comes to join the dispersed airflow of the powder and granular material from the entire outer periphery of the opening of the swirling nozzle 28 by the heated airflow introduction part 33. As a result, the surfaces of the powder and granules in the dispersed air flow are melted and spherical, and fine powder and granules are granulated to form new granules. Thereafter, the solidified granules are cooled and solidified by the cooling air supplied from the cooling air supply mechanism 4, and then the solidified granules are sent into the cyclone 5, where the solidified granules are separated and the particles are placed in the collector. It will be supplemented.

On the other hand, an exhaust flow is discharged from the air outlet at the upper part of the cyclone 5.

According to the embodiments described above, since the diffusion air flow supply mechanism 29 that supplies the diffusion air flow inside the swirl nozzle 28 is provided, the dispersion air flow of the powder and granules is supplied to the diffusion air flow nozzle inside the swirl nozzle 28. It collides with the diffusion airflow supplied from the swirling nozzle 30 and the flow is disturbed, and therefore, the swirling airflow that was flowing unevenly along the inner wall of the swirling nozzle 28 due to centrifugal force is also diffused to the inner side of the swirling nozzle 28. As a result, the dispersion airflow of powder particles is discharged downward from the opening of the swirling nozzle 28 with the thickness D of the empty conical airflow layer increasing, and as a result, the dispersion airflow The spatial concentration of the powder and granules therein becomes low and the powder and granules are well dispersed with a small density. Therefore, when heated by a heated air stream, coarsening due to adhesion of powder and granules is prevented, and the granulation degree is kept small, resulting in a high yield of small and uniformly sized powder particles. . Since the powder and granules can be dispersed at a low spatial concentration in this manner, the supply amount of the powder and granules can be increased and the powder and granules can be heat-treated at a higher yield. Since the dispersion airflow of the powder particles is discharged from the opening of the swirling nozzle 28 with its speed reduced by the diffusion airflow, the thermal association time with the heated airflow becomes longer, and therefore the heat treatment Good heat treatment can be performed without introducing insufficient particles. Since the heated airflow is supplied from the upper part of the outer wall of the swirling nozzle 28 toward the entire outer periphery of the opening of the swirling nozzle 28 by the heated airflow introduction part 33, the powder and granular material discharged from the opening of the swirling nozzle 28 is dispersed. is in a state where it is heated while being surrounded by a heated air current, so that the powder particles are less likely to scatter, and the powder particles can be heat-treated without contaminating the inside of the apparatus.

Although the present invention has been described above with respect to the case where it is used in a toner heat treatment process, the heat treatment apparatus of the present invention can also be used when heat treating powder or granular materials other than toner.

〔Effect of the invention〕

As described above, the present invention provides a heat treatment apparatus for heat-treating powder and granular materials in an air stream, which includes a swirling mechanism for swirling an airflow for dispersing powder and granular materials, and a dispersion of the swirled powder and granular materials by the swirling mechanism. and a heating mechanism that heats the airflow, and the swirling mechanism includes:
The heat treatment apparatus is characterized by comprising a swirling nozzle that discharges a dispersion airflow, and a diffusion airflow supply mechanism that supplies the dispersion airflow to the inside of the swirling nozzle. The particles are swirled inside the swirling nozzle and are disturbed and diffused by the diffusion airflow, so that the powder particles are discharged from the swirling nozzle in a well-dispersed state with a small density.

Therefore, during the heat treatment, coarsening due to cohesion of the powder particles is suppressed, and as a result, particles with small diameters and uniform particle sizes can be obtained at a high yield.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram schematically showing an embodiment of the heat treatment apparatus of the present invention, and FIGS. 2 and 3 are an explanatory longitudinal sectional front view and an explanatory bottom view, respectively, showing enlarged main parts of the turning mechanism. be. 1... Heat treatment container 2... Rotating mechanism 3...
Heating mechanism 4... Cooling air supply mechanism 5... Cyclone 6... Dust collector 7... Exhaust mechanism
21...Ejector part 22...Swivel part
23... Compressed air flow introduction port 24... Supply port
25...Mixing chamber 26...Throat part
27... Turning chamber 28... Turning nozzle 29.
...Diffusion airflow supply mechanism 30...Diffusion airflow nozzle
31... Air supply section '32... Part of the heater
33... Heated air flow introduction section 34... Rectification section

Claims (1)

[Scope of Claims] 1) A heat treatment device for heat-treating powder and granular material in an air stream, comprising: a swirling mechanism that swirls an airflow dispersing the powder and granular material; and a dispersion airflow of the powder and granular material swirled by the swirling mechanism. a heating mechanism that heats the air, and the swirling mechanism includes a swirling nozzle that discharges a dispersed airflow, and a diffusion airflow supply mechanism that supplies a diffusion airflow to the inside of the swirling nozzle. Heat treatment equipment. 2) The heat treatment apparatus according to claim 1, wherein the heating mechanism has a heated air flow introduction section that introduces the heated air flow from the outer periphery of the opening of the rotating nozzle.