JPH052986B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for spheroidizing toner used in a copying machine.

Conventionally, when manufacturing toner for copying machines, a release agent is added to carbon, dye, resin, etc., these are mixed in a kneader while being heated, the mixture is cooled and solidified, and then pulverized. Fine powder toner having a particle size below a certain level is classified, and if necessary, the toner is subjected to surface treatment or additives are added to obtain toner powder as a product.

However, as mentioned above, it is known that powdered toner obtained by simply pulverizing solid toner generally has sharp, angular protrusions on its outer surface when viewed microscopically. . It is known that when a copying machine is used for a long period of time, a phenomenon in which image density generally decreases occurs, and one of the reasons for this phenomenon is the occurrence of corners formed on the outer surface of toner powder as described above. It has recently become clear that.

Therefore, an object of the present invention is to provide a novel device for abrading the corners of toner powder having sharp edges through a crushing process to make it spherical. A cylindrical outer cylinder, an air nozzle provided in the outer cylinder, an outer guide cylinder provided vertically in the outer cylinder, and an air nozzle inserted into the upper end opening of the outer guide cylinder through a cylindrical gap. The outer cylinder has an inner guide cylinder whose one end is connected to a negative pressure source, and the toner powder supplied from the side of the outer cylinder is given a swirling motion by the air flow injected from the air nozzle, and the toner powder is mutually or The present invention provides a toner spheronizing device in which the toner powder is spheroidized by collision with the inner surface of the outer cylinder, and then taken out of the outer cylinder through the gap and inside the inner and outer guide cylinders.

Next, embodiments embodying the present invention will be described with reference to the accompanying drawings to provide an understanding of the present invention.

1 and 2 are a front view and a side view showing an example of a toner manufacturing apparatus having a toner spheronizing device according to the present invention, and FIG. 3 is a side view showing an example of the toner spheronizing device. Figures 4 and 5 are views taken along arrow A-A in Figure 3, and Figure 6, respectively.
FIG. 7 is a side sectional view showing an example of a toner spheroidizing device connected to an air bleed device, FIG. 7 is a side sectional view showing a toner spheroidizing device having a large number of air nozzles, and FIGS. FIG. 2 is a side sectional view showing an example of an airflow swirling device in the conversion device.

In FIGS. 1 and 2, 1 is a cyclone separator, which is a type of classification device, and has a fine powder outlet 2 on its side, and a coarse powder discharge section 4 connected to a conveying pipe 3 at the bottom thereof. have.

The conveying pipe 3 is connected to a coarse powder inlet 6 of a crushing device 5 provided below the cyclone separator 1. A discharge section 7 is provided.

In the conventional toner manufacturing apparatus, the toner discharge section 7 is directly connected to the toner intake port 8 of the cyclone separator 1 in the upper part in a loop shape, and the pulverizing device 5
The toner powder pulverized by the cyclone separator 1 is such that only the toner having a particle size below a certain level is taken out of the system from the fine powder outlet 2 without being sphericalized. In this case, a toner spheroidizing device 9 is connected between the toner discharge section 7 of the pulverizing device 5 and the toner intake port 8 of the cyclone separator 1 for controlling the toner spheroidizing process.

The part to which the toner spheroidizing device 9 is connected is not limited to the part between the toner discharge part 7 and the toner intake port 8 as described above, but is also connected to the coarse powder discharge part 4 of the cyclone separator 1.
In other words, the conveying pipe 3 may be cut in the middle and inserted between the coarse powder inlet 6 of the crushing device 5, but in this case, the toner that has been sphericalized and has rounded edges is The toner particles are crushed by the crushing device 5, resulting in toner powder having sharp corners, which is discharged from the cyclone separator 1, and the effectiveness of the toner spheronizing device 9 is significantly reduced.

In this respect, as in the toner manufacturing apparatus shown in FIGS. 1 and 2, there is By inserting the toner spheroidizing device 9 to form a loop-shaped circulation process, the corners of the toner powder having sharp corners generated in the crushing device 5 are rounded by the toner spheroidizing device 9. In this way, only the spherical toner powder is sent to the cyclone separator 1, from which it is taken out of the system through the fine powder outlet 2.
The spheroidization of the product to be taken out is significantly promoted.

Note that the toner supply port 11 of the toner spheroidizing device 9
and the toner discharge section 7 of the crushing device 5 are connected by a conveying pipe 10, and the toner discharge port 12 of the toner spheroidizing device 9 and the cyclone separator 1
is connected to the toner intake port 8 by a conveyance pipe 13, and a supply pipe 14 for supplying coarse toner raw material powder is connected to the conveyance pipe 13.

Therefore, the toner coarse powder that flows into the conveying pipe 13 from the supply pipe 14 due to the negative pressure of the cyclone separator 1 flows into the cyclone separator 1 from the toner intake port 8, and the swirling airflow generated inside the cyclone separator 1 The vehicle rotated around the vehicle, collided with the side wall of cyclone separator 1, and lost speed.
From the coarse powder discharge section 4, the toner enters the pulverizing device 5 via the conveying pipe 3 and the coarse powder inlet 6, and after being finely pulverized in the pulverizing device 5, passes through the toner discharging section 7, the conveying pipe 10, and the toner supply port 11. The toner flows into the toner spheroidizing device 9, where it is subjected to a spheroidizing action which will be described later, and then flows into the cyclone separator 1 again through the toner intake port 8 through the toner discharge port 12 and the conveying pipe 13.

The toner powder that has flowed into the cyclone separator 1 again in this way is finely pulverized by the pulverizer 5, and its corners are rounded by the spheroidizer 9, so that the centrifugal force received within the cyclone separator 1 is small due to its small mass. Therefore, the fine powder is taken out from the loop-shaped system through the fine powder outlet 2 while riding on the swirling air current.

Supply pipe 14 for supplying the above toner coarse powder
can also be connected to the conveying pipe 3 or 10, but as shown in FIGS. 1 and 2, the conveying pipe 13, which is most exposed to the negative pressure of the cyclone separator 1,
By connecting to the supply pipe 14, the flow of the toner powder within the supply pipe 14 is ensured, and there is no possibility that the supply pipe 14 will become clogged.

The above-mentioned classification device is not limited to the above-mentioned cyclone separator, but it is possible to use a centrifuge, a filter, and other well-known devices.
Also, a well-known one can be used.

Next, the structure and operation of the toner spheroidizing device 9 will be described in detail. FIG. 3 shows an example of the internal structure of such a toner spheronizing device 9. In this case, the toner spheronizing device 9 includes a generally cylindrical outer cylinder 1.
5 has an outer guide tube 16 coaxial with the outer tube 15 at the center thereof, and this outer guide tube 16 has a structure in which the lower end is sealed and the upper end is open. The outer guide tube 1
an inner guide cylinder 18 coaxial with 6 and whose upper end communicates with a toner discharge port 12 connected to the cyclone separator 1, which is an example of the negative pressure source;
is inserted through a gap 19, and the lower end of the inner guide tube 18 is open, and the space 18a inside the inner guide tube 18 and the space 16a inside the outer guide tube 16 are connected to the inner guide tube 18. It communicates through the lower end opening 20 of.

The amount of insertion of the inner guide tube 18 into the outer guide tube 16 is set according to various conditions such as the negative pressure inside the inner guide tube 18 and the dimensions of the inner and outer guide tubes 18 and 16, and is variable as necessary. It is said that

Further, the toner supply port 11 connected to the conveying pipe 10 is attached to the outer cylinder 15, and
As shown in FIGS. 3 and 5, the outer tube 15 is in communication with the inner space 15a.
A plurality of air nozzles 21 are attached that protrude into the space 15a within the space 15a.

As shown in FIGS. 4 and 5, this air nozzle 21 has its tip oriented in the circumferential direction of the outer cylinder 15 and inclined downward, so that the compressed air injected from the air nozzle 21 is directed within the outer cylinder 15. This is for giving a swirling motion to the toner powder that swirls and flows into the outer cylinder 15 from the toner supply port 11 .

Further, the lower end of the outer cylinder 15 is desirably formed into a bottomed conical shape having a tapered surface 22 whose cross-sectional area decreases downward as shown in FIG.

As shown by the arrow 23, the air nozzle 21 constantly injects a downward air flow in the circumferential direction, and the toner powder that has flowed in from the toner supply port 11 rides on this swirling flow and swirls at high speed to form the outer cylinder 15.
By colliding with the inner surface of the toner and colliding with each other, the sharp corners formed on the powder surface are worn away and rounded, and the powder as a whole becomes spherical.
By descending along the inner surface of the outer cylinder 15 and eventually turning along the inner surface of the tapered surface 22, its turning radius is narrowed, and it collides with the lower end of the outer cylinder 15 and reverses into an upward swirling flow. It ascends while turning around the outer guide cylinder 16. In order to assist this upward flow, a horizontal nozzle that generates a swirling airflow may be added above the nozzle 21.

On the other hand, the space 18a inside the inner guide cylinder 18 is connected to the toner discharge port 12 which communicates with the cyclone separator 1, which is a type of negative pressure source, as described above, and is in a negative pressure state, so it communicates with this. The internal space 16a of the outer guide tube 16 and the gap 19 between the two guide tubes 16 and 18 are also exposed to negative pressure, and the toner powder that has risen along the outer guide tube 16 is forced into the gap by the negative pressure in the gap 19. 19 as shown by the arrow 24, and further the outer guide cylinder 1
The toner reaches the toner outlet 12 through the space 16a in the inner guide cylinder 6 and the space 18a in the inner guide cylinder 18, and then flows into the cyclone separator 1 through the conveying pipe 13 and the toner intake port 8, and the toner particles of a certain particle size therein are Only the following fine powders are discharged from the fine powder outlet 2 to the outside of the system.

As mentioned above, the reason why the negative pressure in the inner guide cylinder 18 is made to act on the space 15a in the outer cylinder 15 through the gap 19 is that the negative pressure in the space 18a is quite strong, and it is directly applied to the space 15a. When connected to
This is because, due to this negative pressure, the toner powder is sucked into the space 18a before it gets on the swirling airflow from the air nozzle 21, and the swirling movement of the toner powder within the space 15a and the spheroidizing function are no longer performed. Therefore, it is necessary to limit the degree of negative pressure at the upper end opening 17 of the outer guide tube 16 due to the fluid resistance when passing through the gap 19 narrowed to a small area. It is important to adjust the amount to the appropriate amount, so
The vertical length l of the gap 19 and its thickness d
It is necessary to properly determine the

Note that the number of air nozzles 21 may be two in the circumferential direction as shown in FIG. 5, or one as shown in FIG.
Furthermore, in order to strengthen the swirling flow within the space 15a, a large number of air nozzles 21a are installed as shown in FIG.
may be arranged along the outer cylinder 15.

However, as shown in the figure, when the flow rate of air from the air nozzle 21 or 21a increases, the amount of air flowing into the spaces 16a and 18a through the gap 19 increases, and all of this air flows into the cyclone separator 1. If it flows in, the degree of negative pressure in the cyclone separator 1 will weaken, and there is a possibility that its classification function will deteriorate. Therefore, as shown in FIG.
It is desirable to maintain negative pressure inside. FIG. 6 shows a toner spheroidizing device 9 as shown in FIG.
2 shows a state in which the air venting device 25 is connected.

It is desirable to provide a mechanism for actively lifting the toner powder that has reached the bottom 26, and a mechanism as shown in FIGS. 8a and 8b is conceivable. The blade 29 shown in FIG.
By rotating the spiral blade 2 in the direction of
9 is intended to generate an upward swirling airflow in the center of the outer cylinder 15.

Also, what is shown in FIG. b is the bottom part 2 of the outer cylinder 15.
6 is attached with a propeller 31 that rotates around a vertical axis by a motor 27, and the rotation of this propeller 31 is intended to generate an upward air current.

As described above, the present invention includes a vertically erected cylindrical outer cylinder, an air nozzle provided in the outer cylinder, an outer guide cylinder vertically provided in the outer cylinder, and an outer guide cylinder. The inner guide cylinder has one end inserted into the upper end opening through a cylindrical gap and connected to a negative pressure source, and the toner powder is injected from an air nozzle onto the toner powder supplied from the side of the outer cylinder. After the toner powder is given a swirling motion by an air flow and collides with each other or with the inner surface of the outer cylinder to make the toner powder spherical, the toner powder is taken out of the outer cylinder through the gap and the inner and outer guide cylinders. Since this is a toner spheroidizing device, it is possible to promote the spheroidization of the toner when taking out the toner powder that has been pulverized below a certain particle size out of the system, and the toner can maintain the image density for a long period of time. can be manufactured.

[Brief explanation of the drawing]

1 and 2 are a front view and a side view showing an example of a toner manufacturing apparatus having a crushing device, a classifying device, and a toner spheroidizing device that can be used directly to carry out the toner manufacturing method according to the present invention, FIG. 3 is a side view of the toner spheronizing device, FIGS. 4 and 5 are views taken along the line A-A in FIG. FIG. 7 is a side sectional view showing an example of a toner spheronizing device, and FIGS. 8a and 8b are side sectional views showing an example of an airflow swirling device in the toner spheronizing device. It is. Explanation of symbols, 1...Cyclone separator (classifier), 5...Crushing device, 9...Spheronization device,
15... Outer tube, 18... Inner guide tube, 16...
Outer guide tube, 19... gap.

Claims (1)

[Scope of Claims] 1. A cylindrical outer cylinder erected vertically, an air nozzle provided in the outer cylinder, an outer guide cylinder vertically provided in the outer cylinder, and an outer guide cylinder installed vertically in the outer cylinder. It has an inner guide cylinder inserted into the upper end opening through a cylindrical gap and one end of which is connected to a negative pressure source, and air is injected from an air nozzle onto the toner powder supplied from the side of the outer cylinder. After the toner powder is given a swirling motion by the flow and collides with each other or with the inner surface of the outer cylinder to make the toner powder spherical, the toner powder is taken out of the outer cylinder through the gap and inside the inner and outer guide cylinders. Features a toner spheroidizing device. 2. The toner spheroidizing device according to claim 1, wherein the air nozzle is attached to the outer cylinder in a circumferential direction and inclined downward. 3. The toner spheroidizing device according to claim 1, wherein the bottom of the outer cylinder is formed into a conical shape with a bottom.