JPH04372959A - Manufacture of toner and classifying device used for it - Google Patents

Abstract

PURPOSE:To manufacture the toner with stable quality by dropping the toner powder stuck on the tube wall of a duct without damaging the duct and generating a large noise, or preventing the toner powder from being stuck. CONSTITUTION:In the classification process to crush the pellets obtained by kneading and cooling the toner constituent and select the toner powder with a proper grain size, injection pipes 16 with downward injection ports 16a are arranged along the inner side face 15b of a duct 15 for discharging the toner powder, and the toner powder stuck on the inner side face 15b of the duct 15 is blown off by the compressed gas injected through the injection pipes 16 and sent to the next process.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing toner used for development in electrophotography and a classification apparatus used therein.

Toner used in electrophotography is an important functional material that ultimately determines the quality and value of hard copy images, and includes coloring materials, binder resins, charge control agents, fluidizing agents, etc. It is constructed by adding various materials internally or externally.

In the toner manufacturing process, the pellets obtained by kneading and cooling various toner components are pulverized to finer particle size, and toner powder with an appropriate particle size is selected from the finely pulverized toner powder. A classification device is used to separate the raw materials into products.

0004

[Prior Art] A conventional classification device uses a duct installed to guide fine powder whose particle size is too small among toner powder raw materials supplied together with primary air to a secondary At the same time, toner powder having a larger particle size than the fine powder is discharged from a duct provided below.

[0005] The raw material for toner powder is pulverized into a fine particle size by repeatedly colliding with a collision plate inside or outside a classifier, and is finally finely pulverized to a particle size of about 5 to 10 μm. The material is then sent to a process for externally adding inorganic fine powders such as silica, alumina, and titanium oxide.

[0006]

[Problems to be Solved by the Invention] In the classification apparatus at each stage, there is a problem in that toner powder adheres or accumulates on the inside of the tube wall of the duct.

[0007] The toner powder adhering to the tube wall solidifies over time, obstructing the normal flow of the toner powder. Particularly in the final stage classification device, solidified toner powder may peel off due to impact and mix with normal toner powder, leading to a decrease in the quality of toner products.

[0008] In order to drop the adhered toner powder, the outer wall of the duct may be hit with a hammer or the like, but this will damage the duct and also generate large noise.

[0009] In view of the above-mentioned problems, the present invention allows toner powder adhering to the pipe wall of the duct to fall without causing damage to the duct or generating large noise, or to prevent toner powder from adhering to the duct. The present invention aims to provide a method for producing toner of stable quality, and a classification device for the same.

0010

[Means for Solving the Problems] In order to solve the above-mentioned problems, the method according to the invention of claim 1 uses pellets obtained by kneading and cooling toner components, as shown in FIGS. 1 and 4. In the classification process for pulverizing and sorting toner powder of appropriate particle size, jet ports 16a and 17a are installed along the inner surface 15b of the duct 15 for discharging the toner powder.
The ejection pipes 16 and 17 are arranged in such a manner that they are directed downward.
The toner powder adhering to the inner surface 15b of the duct 15 is blown away by the compressed gas ejected from the ejection pipes 16 and 17, and sent to the next step.

[0011] In the method according to the second aspect of the invention, nitrogen gas obtained by fractional distillation of liquid air is used as the compressed gas.

In the classification device 1 according to the third aspect of the invention, a duct 15 in the shape of an inverted truncated cone for discharging the toner powder is provided.
Along the inner surface 15b, ejection pipes 16 and 17 are provided along the inner surface 15b to blow off toner powder adhering to the inner surface 15b using compressed gas.
It is arranged with 17a facing downward.

[0013]

[Operation] Highly purified compressed gas containing no moisture, such as nitrogen gas, is ejected from the ejection ports 16a and 17a of the ejection pipes 16 and 17, thereby blowing away the toner powder adhering to the inner surface 15b of the duct 15. It will be done.

The blown toner powder is transferred to the duct 15.
Other ducts, hoppers, tanks, etc. connected to the
Sent to the next process.

[0015]

[Embodiment] FIG. 1 is a cross-sectional front view schematically showing a classification device 1 according to the present invention, FIG. 2 is an enlarged cross-sectional view of a duct 15 and a jet pipe 16 shown in FIG. 1, and FIG. It is a sectional view taken along the line.

The classification device 1 includes a raw material supply port 11, a center core 12, and a secondary air supply port 1 for supplying secondary air.
3. Duct 14 for discharging fine powder; Duct 15 for collecting selected toner powder FP with an appropriate particle size.
, and an ejection pipe 16.

The raw material supply port 11 is an inlet for supplying raw materials for toner powder FP together with primary air. The raw material for the toner powder FP is pellets obtained by kneading and cooling toner components, or coarsely pulverized pellets.

The raw material supplied from the raw material supply port 11 swirls in the chamber and flows downward from the periphery of the center core 12, but the fine powder whose particle size is too small is light and therefore flows from the secondary air supply port 13. duct 14 from the center by the air flow of
and is discharged from the duct outlet 14a.

On the other hand, the toner powder FP, which has a larger particle size and is heavier than the fine powder, falls downward, flows into the inverted truncated cone-shaped duct 15, and is discharged from the duct outlet 15a.

The ejection pipe 16 is located on the inner surface 15b of the duct 15.
Blow away the toner powder FP attached to the inner surface 15b.
This is to prevent the toner powder FP from adhering to the inside surface 15b, and a plurality of them are arranged at equal intervals in the circumferential direction of the inside surface 15b with the spout 16a facing downward along the inside surface 15b. There is.

A pipe (not shown) is connected to the jet pipe 16, and nitrogen gas of 3 to 5 atmospheres is supplied from the pipe and is jetted downward from the jet port 16a.

The nitrogen gas used here is nitrogen gas obtained by fractional distillation of liquid air, contains almost no moisture, has high purity, and is low cost. Although not shown, a filter, a pressure gauge, a regulator, a stop valve, a tank filled with nitrogen gas, and the like are connected in this order to the piping connected to the ejection pipe 16.

Therefore, the raw material supplied from the raw material supply port 11 is separated into fine powder with a small particle size and the other toner powder FP, and the toner powder FP with an appropriate particle size is supplied from the duct outlet 15a of the duct 15. Only the waste is sorted and discharged.

The toner powder FP that has adhered or is about to adhere to the inner surface 15b of the duct 15 is blown off by the nitrogen gas ejected from the ejection pipe 16, so that
Do not adhere or deposit on b. Therefore, particles attached to the inner surface 15b are not mixed into the toner powder FP, and a toner with stable quality can be manufactured.

Moreover, since the duct 15 is not hit with a hammer as in the conventional case, no damage is caused to the duct 15, and no large noise is generated.

For example, a quarter-inch stainless steel pipe is used as the jet pipe 16, and the jet port 1 at the tip thereof is
When deforming 6a to approximately 2 x 7 mm, the ejection pipe 1
If the pressure of the nitrogen gas supplied to the inner surface 15b is about 3 atm, the noise caused by the nitrogen gas jet is small, and the inner surface 15b
The effect of removing toner powder FP from the toner powder is also sufficient.

FIG. 4 shows a jet pipe 1 according to another embodiment of the present invention.
7 is an enlarged cross-sectional view showing FIG.

The ejection pipe 17 is composed of an outer wall 18a, an inner wall 18b, and an upper lid 18c, which are arranged parallel to each other, and has a cylindrical ejection chamber 19 formed inside, and an annular ejection opening 17a formed at the lower part. There is.

The compressed nitrogen gas supplied from the supply pipe 20 once flows into the ejection chamber 19 and is ejected from the ejection port 17a. As a result, the toner powder FP adhering to the inner surface 15b of the duct 15 is blown off and discharged from the duct outlet 15a.

In the above embodiment, the duct 15 of the classifier 1 is provided with the ejection pipes 16 and 17, but another duct, hopper, or toner powder connected after the duct 14 or the duct 15 is provided. Ejection pipes 16 and 17 may be provided in a tank or the like for recovering FP. Spout pipe 1
A gas suction device or exhaust device with a filter may be provided in order to exhaust the compressed gas ejected from 6, 17.

In the above embodiment, nitrogen gas was used as the compressed gas, but other highly purified gases that do not contain moisture and have a dew point of -65 degrees Celsius or lower, for example, may be used. The working pressure of compressed gas is
Various changes can be made depending on the dimensions, etc.

[0032]

[Effects of the Invention] According to the present invention, toner powder adhering to the pipe wall of the duct can be dropped or prevented from adhering to the pipe wall of the duct without causing damage to the duct or generating large noise. , it is possible to produce toner with stable quality.

According to the second aspect of the invention, moisture, impurities, etc. are not mixed in due to the jetting out of the compressed gas.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional front view schematically showing a classification device according to the present invention.

FIG. 2 is an enlarged cross-sectional view of the duct and ejection pipe shown in FIG. 1.

FIG. 3 is a sectional view taken along the line III-III in FIG. 2;

FIG. 4 is an enlarged sectional view showing an ejection pipe according to another embodiment of the present invention.

[Explanation of symbols]

1 Classification device 15 Duct 15b Inner surface 16,17 Ejection pipe 16a, 17a spout

Claims (3)

[Claims] 1. A method for producing a toner used for development in electrophotography, the method comprising: a classification step for pulverizing pellets obtained by kneading and cooling toner components to select toner powder of appropriate particle size; In this case, ejection pipes (16) and (17) having ejection ports (16a) and (17a) directed downward are disposed along the inner surface (15b) of the duct (15) for discharging the toner powder. Set aside the duct (15
) The toner powder adhering to the inner surface (15b) of the toner is blown away by compressed gas ejected from the ejection pipes (16) and (17), and the toner powder is sent to the next step. 2. The method for producing toner according to claim 1, wherein nitrogen gas obtained by fractional distillation of liquid air is used as the compressed gas. 3. A classification device (1) for sorting toner powder of appropriate particle size by pulverizing pellets obtained by kneading and cooling toner components, the classification device having an inverter for discharging the toner powder. Inner surface (15b) of truncated conical duct (15)
Along the inner surface (15b), the inner surface (1
Ejection pipes (16) and (17) for blowing away toner powder adhering to the ejection port (16a) with compressed gas are connected to the ejection port (16a).
) (17a) is arranged in a state facing downward.