JPS604731B2 - Grinding powder spheroidization furnace equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pulverizing powder spheroidizing furnace apparatus, and particularly to a pulverizing powder spheroidizing furnace apparatus for spheroidizing powder containing a synthetic resin such as toner used in an electrostatic recording device. When the powder is a toner, it is possible to prevent the occurrence of undesired fogging during electrostatic recording without impairing the fluidity of the powder, improve resolution, and eliminate undesired offset states. The present invention relates to a pulverizing powder spheroidizing furnace device for producing toner that prevents the occurrence of .

Although the present invention is not limited thereto, toner used in electrostatic recording devices and electrophotographic devices may contain coloring agents such as coloring pigments (generally fine carbon black particles) and dyes (in some cases, some or all of them). It is composed of a powdered material in which magnetic particles (sometimes containing magnetic particles) are dispersed in a resin.

Further, if necessary, it is constituted by a powder material in which the peripheral surface of the powder material as described above is further sprinkled with the above-mentioned fine carbon particles. As is well known, natural resins may be used in addition to synthetic resins as toner resins, or both may be used in combination. In order to obtain good resolution during electrostatic recording, it is desirable that such a powder be a spherical body with a diameter of 4 mm, and carbon particles may exist in a free state. Alternatively, it is desirable to prevent the occurrence of undesirable fogging or offset conditions caused by the presence of the particles in a form that is easily released.

The above-mentioned fogging state can be thought of as a phenomenon in which fine carbon particles adhere to the periphery of an image in an undesired manner on a hard copy, causing blurring of the image, and the above-mentioned offset state refers to, for example, a phenomenon in which fine carbon particles adhere to the periphery of an image on a hard copy, causing a blurring of the image. This can be thought of as a phenomenon in which the white background on a hard copy is smeared by the adhesion of the white background. In producing the above-mentioned preferred toner, conventionally, after pulverizing a mixture obtained by uniformly dispersing fine carbon particles in a synthetic resin into pulverized bodies having a diameter of about 10 to 30 mounds, for example, A so-called spheroidizing furnace apparatus is used to form powder into a spherical powder that is almost perfectly circular and has a small variation in diameter. That is, the pulverized material is sent into the spheroidizing furnace in a state where it is dispersed in the air, for example, in the form of mist,
The synthetic resin is melted or softened in the spheronizing furnace and spheroidized by surface tension. However, in the case of the above-mentioned spheroidizing furnace, the temperature inside the furnace tends to become non-uniform because the pulverized powder is dispersed in a gas (for example, air) and fed into the furnace.

For this reason, the manufactured toner may not always be sufficiently spherical, and the synthetic resin may not adhere sufficiently around the carbon particles, and the synthetic resin may not have sufficient holding power to hold the carbon particles. occurs. That is, for this reason, the above-mentioned undesirable fogging and offset conditions are likely to occur during electrostatic recording. Furthermore, conventionally known furnaces have the disadvantage that toner adheres to the furnace walls, particularly the ceiling of the furnace, and multiplies, resulting in poor yield. The present invention aims to solve the above problems, and will be described below with reference to the drawings.

Fig. 1 shows an example of a known spheroidizing furnace device, Fig. 2 shows an embodiment of the spheroidizing furnace device of the present invention, and Fig. 3A shows a plan view of an embodiment of the hot air supply device used in the present invention. FIG. 3B shows a sectional view taken along the line X--X' shown in FIG. 3A.

In Fig. 1, 1 is a spheroidizing furnace, 2 is a heating part of the spheroidizing furnace, 3 is a cooling part of the spheroidizing furnace, 4 is a pulverized powder dispersed in atomized form, 5 is a spheroidized powder, 6 is a spheroidizing furnace. 1 is a heater, for example, an infrared panel heater; 7 is a powder conveying device; 8 is a blower; 9 is a hopper for supplying pulverized powder; 10 is an atomization device. For example, the pulverized powder is blown away by an air stream and dispersed in the air stream in the form of a mist and sent to the heating section 2. 11 and 12 are thermocouples that control the heat generation of the heater, and 13 is a cooling unit. Water circulation duct, 14 is an intake port, 15 is a cyclone,
16 represents a collection container with a trolley.

In the case of toner production, as described above, carbon fine particles and the like are uniformly dispersed in, for example, a molten synthetic resin, a solidified kneaded product is pulverized, and the pulverized powder is fed to the hopper 9.

The shape of the pulverized powder generally maintains the non-spherical shape as it is when pulverized, and usually has a diameter of about 10 to 30 r. The pulverized powder supplied to the hopper 9 is atomized by the atomizing device 10 as described above, and sent to the heating section 2 in the form of individual powder particles being dispersed in the air.

The air flow used during the feeding may be, for example, about 2 atmospheres and 4 air per hour. The pulverized powder 4 fed in the form of mist as described above is heated to a temperature of, for example, 100% in the heating section 2.
When heated to about 200 qC, the synthetic resin contained in the pulverized powder 4 melts or softens and becomes spherical by surface tension. The temperature inside the heating section 2 is detected by thermocouples 11 and 12, and is controlled by controlling the supply of electricity to the heater 6. As shown in the figure, the spheroidizing furnace 1 is divided into an upper heating section 2 and a lower cooling section 3.

Then, in the cooling section 3, the temperature of the spherical pulverized body as described above is lowered, and the spherical powder 5 is formed in which the carbon fine particles are captured by the synthetic resin. The powder 5 is further fed to the cyclone 15 side by the blower 8 via the powder conveying device 7, separated from air in the cyclone 15, and collected into a collection container 16. A conventionally known spheronizing furnace apparatus is constructed as described above, and spheroidizes the pulverized bodies. However, as mentioned above, the pulverized powder is fed into the atomized state, and care is taken to create as little turbulence as possible inside the furnace, so the temperature inside the furnace is not as high as shown in the figure. As shown by the position/temperature T curve, the temperature at the center of the furnace is lower than that at the peripheral wall. That is, in the pulverized powder falling through the low-temperature castle, the synthetic resin is not sufficiently melted or softened, and the carbon particles are not sufficiently captured by the synthetic resin. Therefore, when performing electrostatic recording using such toner, carbon particles may become loose and cause undesirable fog, or they may adhere to the fixing roll and cause offset. . Furthermore, the toner is not sufficiently spherical, and the outer diameter of the produced toner varies greatly, resulting in poor resolution. FIG. 2 shows an embodiment of the present invention that solves the above-mentioned problems.
2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12,
13 and 14 correspond to FIG. 1, 17 is a gateway opening into the furnace of the false atomizer, 18 is a hot air supply device produced according to the present invention, 19 is a hot air generator, and 20 is a cooling device, for example, by a water bottle. 3 represents a cooling plate, 21 represents an outside air shielding plate, and 22 represents a hot air laminar flow.

Note that in FIG. 2, the configuration after the blower 8 corresponds to that in FIG. 1, and illustration thereof is omitted. FIG. 3 shows an embodiment of the configuration of the hot air V supply device 18 used in the present invention.

The hot air supply device 18 has a hollow flat plate ring 24 having a through hole 23 in the center thereof through which the above-mentioned closed part 17 penetrates. sent through. Further, in the hollow flat plate ring 24, the hot air outflow surface 2 exposed to the heating section 2 is
6 is provided with a plurality of apertures 27 that are substantially evenly distributed on the surface. - The hot air supply device 18 as specifically shown in FIG. 3 is connected to the furnace 1 as shown in FIG.
The hot air supply device 18 is installed, for example, in the ceiling, and is arranged so as to surround the above-mentioned entrance portion 17.

For example, 100q○ to 200o from the hot air supply layer 18
o hot air is supplied into the heating section 2 in the form of a laminar flow at a rate of, for example, 4 to 10 〆/min. In this state, the pulverized powder atomized from the closed part IT of the atomizer 10 is transferred to the first
As explained in connection with the figure, it is fed into the heating section 2,
It is heated and becomes spherical. The process in which the spherical powder 5 cooled in the cooling section 3 is fed to the cyclone (shown in FIG. 1) via the blower 8 is exactly the same as the case shown in FIG. good. In the case of the present invention, as described above, hot air is fed into the heating section 2 in a laminar flow from the hot air supply device 18 and heated by the heating heater 6, so the temperature inside the heating section 2 is not shown in the figure. As shown by position/temperature T curve A, the temperature is approximately uniform between the central part and the peripheral wall part of the furnace.

It becomes possible to suppress the difference between the highest temperature range and the lowest temperature range in the heating section 2 to about 5°C. According to the inventor's experiment, when only hot air is sent and the heater 6 is left inactive, the temperature inside the furnace decreases near the peripheral wall, exhibiting a tendency as shown in the position/temperature T curve B shown in the figure, and manufacturing Similar to the case shown in FIG. 1, the synthetic resin did not have sufficient ability to capture carbon particles. Furthermore, when the vicinity of the ceiling of the conventional heating section 2 is heated, as described above, the pulverized powder in which the synthetic resin component is in a molten state may adhere to the heated ceiling. However, in the case of the present invention, since a forced flow is created in the heating section 2 by the hot air laminar flow 22, the pulverized powder may undesirably adhere to the hot air outlet surface 26 of the hot air supply device 18, etc. There is no. Further, due to the forced flow, undesired adhesion of the pulverized powder to the inner wall of the heater 6 is almost eliminated, and the recovery rate is improved. As explained above, according to the present invention, the temperature distribution within the heating section 2 becomes uniform, and undesired adhesion of pulverized powder inside the furnace is prevented due to the forced flow caused by the laminar flow of hot air.

Accordingly, during toner production, for example, the toner is almost completely spherical, and the carbon particles are effectively held by the synthetic resin, making it possible to prevent undesired capri and offset from occurring during electrostatic recording. Furthermore, in the case of producing the above-mentioned toner, an improved toner may be produced in which fine carbon particles are further sprinkled on the surface of the above-mentioned spherical body formed into a spherical shape. In this case, the following will suffice: That is, the toner formed into a spherical shape as described above is heated slightly and fine carbon particles are further attached to the surface, and the powder thus formed (or pulverized powder) is supplied to the hopper 9 described above, and the toner is again formed into a spherical shape. It is spheroidized by the curing furnace 1. In this case, the carbon fine particles attached to the surface described above become embedded in the melted or softened synthetic resin, and a desired toner can be obtained. In addition, when manufacturing a powder such as the above-mentioned toner, the correct spherical shape of the powder greatly affects the fluidity of the powder, and furthermore, the heads of carbon particles appear on the surface of the toner. This affects the fluidity mentioned above.

In the case of the present invention, it is possible to substantially strictly control the temperature at which the synthetic resin is melted or softened throughout the furnace. For this reason, it is possible to make the powder into spherules without losing its fluidity, and it is possible to produce a powder that is convenient to handle. In the above description, the present invention has mainly been explained with reference to toner, but the present invention is not limited thereto, and can similarly be used, for example, in the production of adhesive particles formed into powder.

[Brief explanation of drawings]

FIG. 1 shows an example of a conventionally known spheroidizing furnace apparatus, FIG. 2 is an embodiment of the spheroidizing furnace apparatus of the present invention, and FIG. 3A is a plan view of a hot air supply apparatus used in the present invention. FIG. B shows a cross-sectional view taken along the line X--X shown in FIG. 3A. In the figure, 1 is the spheroidizing furnace, 2 is the heating part of the spheroidizing furnace, 3 is the cooling part of the spheroidizing furnace, 4 is the crushed powder dispersed in a mist, 5 is the spheroidized powder, and 6 is the spheroidized powder. heating heater; 7 is a powder conveying device;
8 is a blower, 9 is a hopper, 10' is an atomization device, 18 is a hot air supply device, 19 is a hot air generator, 22 is a hot air laminar flow, 2
6 represents a hot air outflow surface, and 27 represents an opening. Talented and evil na Z evil and talented 3 females

Claims (1)

[Scope of Claims] 1. A hollow cylindrical spheronizing furnace, which is provided at an upper position of the spheronizing furnace, and is provided in the spheronizing furnace by dispersing pulverized powder containing a synthetic resin in a spray state in a gas. a spheroidizing furnace heating section having a heater provided on a wall surface at an upper position of the spheronizing furnace, a spheroidizing furnace cooling section located at a lower position of the spheronizing furnace, and In a pulverizing powder spheroidizing furnace apparatus having a powder conveying device located in a cooling section, a hot air supply device is provided at a position corresponding to an opening opening into the furnace of the atomization device, and the hot air supply device is A pulverized powder spheroidizing furnace apparatus characterized in that hot air is supplied to the heating section in a laminar flow state, and the heater heats the inside of the heating section from a wall surface of the heating section. 2 The hot air supply device is disposed at the upper end of the spheroidizing furnace and has a hot air outflow surface facing the upper end of the spheroidizing furnace, and the hot air outflow surface has a plurality of hot air outflow surfaces substantially uniformly distributed on the surface. The pulverizing powder spheroidizing furnace apparatus according to claim 1, characterized in that it has an opening. 3. Claims 1 or 2, characterized in that the pulverized powder is a pulverized powder obtained by pulverizing a kneaded product in which at least a pigment or dye is solidified with a synthetic resin.
The pulverizing powder spheroidizing furnace apparatus described in 2.