JPS5842057A - Preparation of electrostatic image developing toner - Google Patents

Abstract

PURPOSE:To effectively obtain an electrostatic image developing toner causing low fog at a small cost of power, by preliminarily pulverizing a roughly crushed toner material with an impact breaker, and finely pulverizing it with a jet mill. CONSTITUTION:A raw toner material consisting of synthetic resin, carbon black, etc. is roughly crushed with a hammer mill, etc., and preliminarily pulverized with an impact breaker having a rotor 2 provided with beater blades 2a so as to make weight average particle diameter not to exceed 50mum. Then, it is further micropulverized by beating the pulverized particles 1 with ultrahigh speed air streams injected from a jet nozzle 4 using a jet pulverizer, thus permitting both advantages of the impact and jet pulverizers to be adopted, microparticles causing fog to be prevented, and an intended electrostatic image developing toner to be effectively obtained.

Description

[Detailed Description of the Invention] It is called a toner. ), and particularly relates to an improvement in a pulverization method for obtaining toner by pulverizing coarsely pulverized toner material.

In the conventional toner manufacturing method as described above, a plate-like or lump-like toner material is pulverized using, for example, a hammer set P milling machine, etc.
For example, it is measured using a Coulter Counter manufactured by Coulter Electronics. Hereinafter, it will simply be referred to as the average particle size. ) is 100
- Coarsely pulverized toner material of about 1000 μm is produced, and the coarsely pulverized toner material is fed to an impact-type crusher capable of finely pulverizing it between a rapidly rotating rotating body and a stationary body or other rotating body. Alternatively, the coarsely pulverized toner material as described above may be pulverized using a supersonic jet stream. Supply it to a machine and pulverize it,
There is a method of obtaining a similar toner by classifying the finely pulverized material with air, as shown in the principle diagram in the figure.
There are some as shown in the principle diagram in Figure 3 or Figure 3.

In the impact type crusher shown in FIG. 7, the coarsely crushed particles are beaten by a beater blade λa by the rotation of a rotor tacho, and are crushed by colliding with a fixed or rotating liner 3. In the jet-type pulverizer shown in FIG. 2, the coarsely pulverized particles 'td are beaten by the ultra-high-speed airflow ejected from the jet nozzle, causing the particles to violently collide with each other, and also collide with the casing S to be pulverized. In the jet pulverizer shown in FIG. 3, coarse pulverized particles 1 are beaten by an ultrahigh-speed airflow ejected from a jet nozzle 6, accelerated, and violently collided with a casing 7, thereby being pulverized. The jet type crusher shown in Figure 2 is
Collision between particles is considered to be the main force behind the crushing action.
The jet-type crusher shown in the figure is also called the collision jet type, and the collision with the casing is considered to be the main force of the crushing action.

A pulverizer as described above is used to pulverize coarsely pulverized toner material.

In the method using an impact crusher, the average particle size is 〃μ
Up to a certain level, pulverization is efficient and power consumption is small, but beyond that point, the efficiency decreases rapidly, and for example, if the power consumption is to obtain the average particle size /Iμ, the power consumption is to obtain the average particle size〃μ. However, the average particle size is 1.
It is almost impossible to crush particles to 0μ, and even when sufficiently crushed, the classification yield for an average particle size of 13μ by wind classification is about s%, and the classification yield for an average particle size of IIμ is 25%.
There is a problem that the classification yield is low for toner particles with a preferable particle size range of 10 to 3 μm.

On the other hand, methods using jet-based pulverizers as shown in Figures 1 and 3 consume considerably more power than impact-type pulverizers; Easily obtained and preferred as a toner! θ~/3μ
It is characterized by a high classification yield for particles with a particle size of . On the other hand, toner obtained by crushing and classifying using an impact type crusher tends to cause the Capri phenomenon during copying, whereas toner obtained using a jet type crusher tends to cause the capri phenomenon. Even if the particle size is made uniform by classification, there is a problem that the capri phenomenon is likely to occur. The reason for this is that when pulverized with a jet pulverizer, ultrafine particles that cause the Capri phenomenon are generated, and these particles electrostatically adhere to the surface of particles with a particle size of 10~/Sμ. 10~/3μ without being removed even after classification
This is presumed to be because the particles remain in the particles.

The present invention relates to the particle size of the crushed toner material supplied to the crusher 111 by the capri phenomenon of the toner produced by the crusher using a jet, and the coarsely crushed toner material is pre-milled by an impact type crusher with an average particle size of yuμ. If the pre-pulverized toner material is pre-pulverized as follows and the pre-pulverized toner material is pulverized using a jet-based pulverizer, the capri phenomenon can be reduced without sacrificing the effect of high toner yield. This was done based on the discovery that the conventional method using a pulverizer using a jet requires less power.

The impact type crusher used in the method of the present invention is an impact type crusher capable of finely pulverizing the same as that used in the conventional toner manufacturing method, and the crusher using jets also uses the conventional type. A jet mill similar to that used in the pulverization process is used. That is, examples of impact-type crushers include the Turbo Mill manufactured by Turbo Kogyo Co., Ltd. and the ACM Pulverizer manufactured by Seiyo Ironworks, and examples of crushers using jets include the supersonic jet mill PJM manufactured by Nippon Pneumatinoku Kogyo Co., Ltd. , same ('PJM-
Examples include E.

In the present invention, if the average particle size of the toner material pre-pulverized by the impact type crusher is larger than 50μ, the effect of using the impact type crusher will not be noticeable, and
As mentioned above, if you try to grind toner to the average particle size with an impact grinder, the efficiency of pre-pulverization will decrease, which will increase the overall power consumption, so pre-pulverization is not recommended. It is preferable to limit the average particle size to about 〃μ.

Hereinafter, the present invention will be explained based on examples.

Example 1 Styrene-acrylic resin 100 parts Carbon black 5 parts Negative charge control agent: Orient Kagaku Kogyo Co., Ltd. Parifast 2 parts Low softening point polypropylene resin sm A toner material with an average particle size of 10- i
The powder was coarsely ground to a particle diameter of Xμ, and then pre-pulverized to an average particle size of Xμ using an impact crusher, Turbo Mill T-100 manufactured by Turbo Kogyo Co., Ltd. The pre-pulverized toner material is supplied to supersonic jet mills PJM-Cooo and PJM-I-s manufactured by Nippon Pneumatic Industries Co., Ltd., which are jet-based crushers, and are finely pulverized to an average particle size of 10 μm. were classified by air to obtain toner with an average particle size of 10p.

Those toners are used in a copying machine U-Bi manufactured by Konishiroku Photo Industry Co., Ltd.
When copying was performed 1000 times using the XU and the fog values of the copied images were determined, excellent results were obtained in which the fog values were 0.0/or less in all cases.

In addition, without pre-pulverizing, the coarsely pulverized product can be directly processed using supersonic jet mills PJM-100 and PJM-1-3.
The toner having an average particle diameter lθμ obtained by air classification after being finely pulverized to an average particle diameter of 10μ was 0.03 to 0.0.

In addition, after pre-pulverization, the supersonic jet mill PJM-2
The power consumption when finely pulverizing with 00 and PJM-I-3, including pre-pulverization, was 7 kW-hr for toner lk#9, J, OkW-hr and 87 kW-hr, respectively, including pre-pulverization. If omitted, each! ,! k
W-hr and J,/kW-hr, and the % power consumption was also less ψ in the case of pre-pulverization than in the case of pre-pulverization.

Example 2 Coarsely pulverized toner material having the same average particle size as in Example 1 of 100 to 1000 μm was processed using an impact pulverizer AOM made by Hoiyou Iron Works.
Preliminary pulverization was performed using Pulperysam CM-10 to give an average particle diameter of μ to μ. Each of the pre-pulverized toner materials was passed through a supersonic jet mill PJM-oo.
and PJM-I-1 to obtain wind-classified toner having an average particle diameter of lθμ in the same manner as in Example 1. The fog value of each toner was measured in the same manner as in Example 1, and it was found that the two types of toners that had been pre-pulverized with an average particle size of Vμ were both 0. The one type of toner that was tested was 0.02 to 0.03.

In addition, the power consumption includes pre-pulverization, and the toner that is pre-pulverized to an average particle size of 0μ and finely pulverized with PJM-200 is
j) 1.41kW-hr s Same (PJM -I -
The toner finely pulverized in Step 3 was 2.1 kW-hr, and the toner pre-pulverized to an average particle size of 3θμ and finely pulverized in PJM-200 was L7 kW-hr % circulation (PJM-I
-3 pulverized toner had a power consumption of 2.7 kW-hr.

That is, compared to the case of finely pulverizing using a jet-type pulverizer without pre-pulverizing as shown in Example 1, the capri phenomenon was reduced in this example as well, and the power consumption was lower, but the average particle size lOμ The average particle size is 5 to crush dirt.
In the case of particles pre-milled to θμ, these effects are reduced compared to those pre-milled to an average particle size of Qμ or as in Example 1, pre-milled to an average particle size of μ.

The results in Example 1 and Example 2 above, and further,
As in Example 2, the toner was pre-pulverized to an average particle size of 60 μm, finely pulverized to an average particle size of 10 μm using a supersonic jet mill, and then classified by air. are shown in the table below.

As is clear from the table, the average particle size of the jet crusher is 1.
To grind to 0μ, the average particle size is
If the toner is pre-pulverized to a particle size of less than μ, the resulting toner has excellent effects in that the occurrence of fogging phenomenon is reduced and power consumption is also reduced.

[Brief explanation of the drawing]

FIG. 1 is a principle diagram showing an example of an impact type crusher, and FIGS. 2 and 3 are principle diagrams showing examples of a crusher using jets, respectively.゛Patent applicant: Konishiroku Photography Co., Ltd. Figure 1 Figure 3

Claims (1)

[Claims] In a method of manufacturing a toner for developing an electrostatic image by finely pulverizing a coarsely pulverized toner material, the toner material is pre-pulverized in advance using an impact pulverizer so that the paper weight average particle diameter is 5θμ or less. A method for producing a toner for electrostatic image development, which comprises pulverizing the pre-pulverized toner material using a pulverizer using a jet.