JPH0563215B2 - - Google Patents

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. .

[Technical background]

For example, in a dry electrophotographic copying machine, powder particles called toner are used to 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, apparatuses used for heat treatment of powder and granular materials have been conventionally used to heat-treat the powder and granular materials by bringing a dispersion air stream of the powder and granular materials containing thermoplastic resin as a main component into contact with a heated air stream. In particular, a dispersion airflow of powder particles is introduced into a swirling part and discharged while swirling to form an empty cone-shaped swirling airflow. It is known that heat treatment is performed by applying heated air currents from the outside or inside of the metal in cross directions.

[Problem that the invention seeks to solve]

However, in conventional devices, in order to form the above-mentioned swirling airflow, the dispersion airflow of powder and granules is introduced into the swirling part from one point, so that the airflow in the direction along the inner circumference of the swirling part is A large deviation occurs in the concentration distribution of powder and granules,
At the exit of the swirling part, a part with a dense spatial concentration of particles is created, so it is extremely difficult to uniformly disperse the powder into the primary particles, and coarse particles are likely to be generated due to thermal fusion of the powder. For this reason, it is difficult to obtain powder particles with a small diameter and uniform particle size at a high yield.

[Purpose of the invention]

The present invention has been made based on the above-mentioned circumstances, and its object is to be able to apply a heated airflow to a swirling airflow in which powder and granules are extremely well dispersed as primary particles, and to As a result, 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 includes a cylindrical swirling part having an axis extending in the vertical direction, which swirls the dispersion airflow of powder and granular material along its inner periphery and then discharges it, and a cylindrical swirling part having an axis extending in the vertical direction. A plurality of dispersion airflow inlets formed at positions such as a dispersion airflow supply mechanism that supplies a dispersed airflow of high-pressure powder and granular material along the tangential direction of a circle centered on the axis of the swirling section, and a heated airflow that applies a heated airflow to the dispersion airflow of the powder and granular material discharged from the swirling section. The invention is characterized in that it has a heated air flow supply mechanism.

[Effect]

According to such a device, the high-pressure dispersed airflow of the powder and granular material supplied from the dispersed airflow supply mechanism is introduced into the swirling section through the dispersion airflow inlet due to the pressure, and is distributed around the inner periphery within the swirling section. However, since there are multiple dispersed airflow inlets in the swirling part and their positions are axially symmetrical,
Because the dispersed airflow from one inlet is swirled and mixed uniformly with the dispersed airflow from the other inlet, the flow velocity distribution and the concentration distribution of the powder and granular material in the direction along the inner circumference of the swirling part become uniform, and as a result, The powder and granules can be sufficiently dispersed as primary particles, and the powder and granules can be discharged from the swirling section in a well-dispersed state with a uniform density. In the heat treatment using air flow, coarsening due to adhesion 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.

〔Example〕

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

FIGS. 1 and 2 are a partially cutaway front view and an explanatory cross-sectional view, respectively, showing essential parts of an embodiment of the heat treatment apparatus of the present invention when viewed from below. This device basically includes a swirling section 1, a dispersion airflow supply mechanism 2 for supplying a dispersed airflow of powder and granular material to the swirling section 1, and a heated airflow for applying a heated airflow to the swirling airflow from the swirling section 1. It consists of a supply mechanism (not shown). The swirling section 1 includes a swirling chamber 11 into which a dispersion airflow of powder and granular material is introduced, and a swirling nozzle 12 that extends downward from the swirling chamber 11 and has a swirling section outlet 26 at its lower end. On the inner circumferential surface of the swirling chamber 11, two dispersed air flow inlets 25 are opened at symmetrical positions with respect to the axis of the swirling chamber 11, that is, at positions approximately equally spaced along the inner circumference.
The dispersed airflow from this direction is the same circumferential direction (second direction).
The dispersion airflow supply mechanisms 2, 2 are connected to each of these dispersion airflow introduction ports 25, respectively. A heated airflow supply mechanism is provided at the outer peripheral portion of the swirling section outlet 26 of the swirling nozzle 12 so that the heated airflow is supplied inwardly and downwardly.

Each distributed airflow supply mechanism 2 in the illustrated example includes a compressed air inlet 21, a powder supply section 22, an ejector mixing chamber 23, and an ejector throat section 24, and includes a compressed air inlet 21, a powder supply section 22, an ejector mixing chamber 23, and an ejector throat section 24. Due to the suction force generated when the powder is ejected into the ejector mixing chamber 23 and passes through the ejector throat section 24, the powder P is gradually supplied from the powder supply section 22 and mixed in the ejector mixing chamber 23. , a high-pressure dispersion airflow of powder and granules is formed. Note that the compressed air inlet 21 is configured to send air in the tangential direction of a circle centered on the axis of the swirling section 1 .

In the configuration described above, the high-pressure dispersed airflow of powder particles formed in each of the dispersed airflow supply mechanisms 2, 2 is introduced into the swirling chamber 11 through each dispersed airflow introduction port 25, and the swirling airflow and The powder and granules then move toward the swirling nozzle 12 and descend while swirling along the inner circumference of the swirling nozzle 12 due to the pressure within the swirling nozzle 12. At this time, the powder and granules are subjected to high shear force and are dispersed into primary particles. The powder is discharged from the swirling part outlet 26, and at this time, the heated airflow from the heated airflow supply mechanism is applied from outside to heat-process the powder and granular material in the dispersed airflow.

In the swirling chamber 11, a plurality of dispersion airflow inlets 25 are formed so that the dispersion airflow of the powder particles swirls in the same direction, so that the swirling chamber 1
1 or the swirling nozzle 12, the deviation that should be caused by the dispersed airflow introduced from one dispersed airflow introduction port 25 becomes disturbed by the dispersed airflow introduced from the other dispersed airflow introduction port 25. .
For example, the formation of a high concentration portion that should be formed by the dispersion airflow introduced from one dispersion airflow introduction port 25 is mutually suppressed by the force of the dispersion airflow from the other dispersion airflow introduction port 25, Therefore, the concentration distribution of the powder and granules is made uniform in the circumferential direction of the rotating nozzle 12, and as a result, the powder and granules are heated in a state where a very high proportion of the particles are dispersed in the primary particles. Under the action of the air current, the surface of the powder and granules in the dispersed air flow is melted and spherical, and the minute powder and granules are granulated to become new powder and granules, so they eventually become smaller in diameter. It is possible to obtain powder particles with uniform particle size in high yield.

A plurality of distributed airflow inlets 25 in the swirling chamber 11
The positions are symmetrical with respect to the axis of the swirling chamber 11, thereby improving the concentration distribution of the powder in the inner circumferential direction of the entire space along the inner circumference of the swirling chamber 11 and the swirling nozzle 12. It can be made uniform. As a result, it is possible to achieve sufficiently good dispersion of the powder and granular material, so that the required heat treatment can be achieved with high efficiency and yield can be increased, and multiple powder and granular material supply mechanisms can be used. 2, it is possible to introduce and process a large amount of powder and granules, increasing processing capacity and processing efficiency at the same time.In the end, heat treatment of powder and granules can be achieved with extremely high efficiency. can.

FIG. 3 shows another embodiment of the invention, in which three distributed air flow inlets 25 are connected to the swirl chamber 11.
are formed at symmetrical positions with respect to the axis, and a distributed airflow supply mechanism 2 is connected to each of them. By forming a large number of distributed airflow introduction ports in this way, it is possible to further improve the uniformity in the direction along the inner circumference of the swirling section 1, and therefore it is possible to further increase the throughput. Of course, a larger number of distributed airflow inlets can also be provided.

FIG. 4 shows yet another embodiment, which includes a heated airflow swirling chamber 31 and an annular dispersed airflow swirling chamber 32 provided around the outer periphery of this heated airflow swirling chamber 31. And heated air flow swirling chamber 3
1, high pressure air is introduced through the heater into the air introduction pipe 33.
The distributed airflow swirling chamber 32 has a plurality of distributed airflow introduction ports 25 formed at symmetrical positions with respect to the central axis, each of which has an introduction pipe for supplying the distributed airflow. 34
are connected so that the swirling direction of the dispersion airflow is the same direction and opposite to the swirling direction of the heated airflow, and the dispersion airflow of the discharged powder and granules is A heated air current is applied so as to intersect from the inside.

FIG. 5 shows yet another embodiment, which includes a cylindrical heated air flow supply section 41 and an annular distributed air flow swirling chamber 42 provided around the outer periphery of this heated air flow supply section 41. It becomes. A heated air jet nozzle 43 that opens diagonally downward is formed at the outer peripheral edge of the lower end of the heated air flow supply section 41, and a plurality of distributed air flow inlets are provided in the upper part of the distributed air flow swirling chamber 42, symmetrically with respect to the central axis. At the same time, a dispersion airflow outlet 44 is formed at the lower end and is oriented radially inward, and the dispersion airflow of the discharged powder and granules is heated so as to intersect with the dispersion airflow from inside. Airflow is applied.

Also in these devices, since there are a plurality of dispersed air flow introduction ports in the swirling section, it is possible to achieve heat treatment of powder and granular materials with extremely high efficiency, as in the above-mentioned examples.

FIG. 6 schematically shows a heat treatment system incorporating a powder heat treatment device. In this figure, 5
0 is a heat treatment device, 51 is a heat treatment container, 52 is a heated air flow supply unit, 53 is a blower, 54 is a heater, 5
5 is a cooling air supply mechanism, 56 is a cyclone, 57 is a dust collector, and 58 is an exhaust mechanism.

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

〔Effect of the invention〕

As described above, the present invention provides a cylindrical swirling section having an axis extending in the vertical direction, which swirls a dispersion airflow of powder and granular material along its inner periphery and then discharges the dispersion airflow, A plurality of dispersed air flow inlets are formed at symmetrical positions with respect to the axis, and the swirling direction of the dispersed air flow of the granular material introduced by the pressure from each of the dispersed air flow inlets is the same direction. a dispersion airflow supply mechanism that supplies a dispersed airflow of high-pressure powder and granular material along the tangential direction of a circle centered on the axis of the swirling section; Since this apparatus is characterized by having a heated airflow supply mechanism that applies an airflow, the high-pressure dispersion airflow of the powder and granule supplied from the dispersion airflow supply mechanism is dispersed by the pressure. The airflow is introduced into the swirling part through the airflow inlet, and is diffused inside the swirling part while swirling along its inner circumference. However, since there are multiple distributed airflow inlets in the swirling part and they are located in an axially symmetrical position, The dispersion airflow from the inlet is disturbed by the dispersion airflow from other inlets, so the flow velocity distribution in the direction along the inner circumference of the swirling part and the concentration distribution of the powder and granular material are shifted to the center of the swirling part. Since it becomes extremely axially symmetrical with respect to the axis and becomes uniform, as a result, the powder and granules can be sufficiently dispersed as primary particles, and the powder and granules are well dispersed with uniform density. Therefore, during the heat treatment using the heated airflow from the heated airflow supply mechanism, coarsening due to adhesion of the powder particles to each other is suppressed, and in the end, particles with a small diameter and uniform particle size are produced. can be obtained in high yield.

[Brief explanation of drawings]

FIG. 1 is an explanatory partially cutaway front view of one embodiment of the present invention, FIG. 2 is an explanatory cross-sectional view of the turning chamber of FIG. 1 viewed from below, and FIG. 3 is an explanatory cross-sectional view of another embodiment of the present invention. FIGS. 4A and 4B are an explanatory plan view of the embodiment, and FIG. FIG. 6, which is a longitudinal sectional front view for explaining the embodiment, is an explanatory diagram showing an outline of a heat treatment system incorporating a powder heat treatment apparatus. 1...Swivel section, 2...Distributed airflow supply mechanism, 11
...Swirling chamber, 12...Swivel nozzle, 21...Compressed air inlet, 22...Powder supply section, 23...Ejector mixing chamber, 24...Ejector throat section, 2
5...Dispersion airflow inlet, 26...Swirling section outlet, 3
DESCRIPTION OF SYMBOLS 1... Heated air flow swirling chamber, 32... Distributed air flow swirling chamber, 33... Air introduction pipe, 34... Introducing pipe for dispersed air flow, 41... Heated air flow supply section, 42... Distributed air flow swirling chamber, 43... ... Heated air flow outlet, 44 ... Dispersion air flow outlet, 50 ... Heat treatment device, 51 ... Heat treatment container, 52 ... Heated air flow supply section, 53 ...
Blower, 54... Heater, 55... Cooling air supply mechanism, 56... Cyclone, 57... Dust collector, 58
...Exhaust mechanism.

Claims (1)

[Scope of Claims] 1. A cylindrical swirling section having an axis extending in the vertical direction, which swirls a dispersion airflow of powder and granular material along its inner periphery and then discharges it; A plurality of dispersed airflow inlets are formed at symmetrical positions, and the swirling direction of the dispersed airflow of the powder and granular material introduced from each of the dispersed airflow inlets due to the pressure thereof is in the same direction. a dispersion airflow supply mechanism that supplies a dispersion airflow of high-pressure powder and granular material along the tangential direction of a circle centered on the axis of the swirling section; What is claimed is: 1. A heat treatment apparatus for powder and granular material, characterized in that it has a heated air flow supply mechanism for acting.