JPH10272379A - Mechanical pulverizer, and production of toner using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the pulverizing performance without enlarging a mechanical pulverizer, by inclining grooves on the inner circumferential face of a cylindrical container relative to the axis of a cylindrical container, regarding the mechanical pulverizer, which is manufactured by installing a freely rotatable cylinder having grooves on the outer circumferential face inside the cylindrical container having the grooves on the inner circumferential face. SOLUTION: In the mechanical pulverizer arranging a rotor 2 in which a plurality of grooves are formed on the outer circumferential face along the axial direction in a cylindrical liner 1, in which a plurality of grooves are formed on the inner circumferential face along the axial direction, while keeping a gap from the inner circumference of the liner 1, the taken substance to be pulverized is pulverized by fiercely swirling flow of air generated by high speed rotation of the rotor 2. In this case, the grooves formed in the inner face of the liner 1 is inclined in the up and down direction of the liner 1. The inclination angle of the grooves in the axis is made different depending on the quantity of air flow for transporting the substance to be pulverized and the pulverized substance toward the discharge outlet 5 from the introduction inlet 4 and preferably controlled to be 10-50 degrees, further preferably to be 20-40 degrees.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mechanical pulverizer and a method for producing a toner using the same.

[0002]

2. Description of the Related Art In a mechanical pulverizer, a plurality of grooves are formed in an inner circumferential surface of a cylinder along an axial direction, and a cross-sectional circumferential shape of the inner circumferential surface is set inside a liner having a predetermined shape from the inner circumferential surface. A plurality of grooves are formed in the outer peripheral surface of the cylinder along the axial direction, and a rotor having an uneven outer circumferential surface in cross section is arranged. Inside the pulverizer, there is formed an airflow for introducing the pulverized material and discharging the pulverized material along the axial direction in the gap. The object to be crushed is put into the gap with this air flow, and is crushed by laminar flow and eddy motion of air generated in the gap as the rotor rotates. The material to be ground advances along the groove of the liner while entering and exiting the groove. On the upstream side of the crusher, volume crushing in which the material to be crushed is mainly crushed to reduce the volume is dominant, and on the downstream side, surface crushing in which the surface is ground and the shape is rounded is dominant. It is a target.

[0003] Toners generally used in electrophotography and the like are:
After mixing and kneading the binder resin, dye and pigment, and other additives, cooling and solidifying the obtained kneaded material, the solidified material is coarsely pulverized, and the obtained coarsely pulverized material is finely pulverized or temporarily pulverized. Then, the above-mentioned mechanical pulverizer is also applied to the pulverizing step or the pulverizing step in the toner production process.

In order to increase the productivity of the toner, it is necessary to improve the pulverizability of the toner in a mechanical pulverizer. Machines are known.

[0005]

However, in the above-mentioned conventional mechanical pulverizer, the pulverizability can be certainly improved, but as a result, the size of the apparatus is increased and the rated torque of the motor for rotating the rotor is reduced. This causes problems such as the need to increase the size.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a mechanical pulverizer having improved pulverizability without increasing the size of an apparatus and a method for producing a toner using the same. .

[0007]

In order to achieve the above object, a mechanical crusher of the present invention has a predetermined gap from the inner peripheral surface inside a cylindrical container having a groove on the inner peripheral surface. In the mechanical pulverizer, a rotatable cylinder having a groove on the outer peripheral surface is arranged, and the pulverization is performed by laminar flow and vortex flow of air generated in the gap with rotation of the cylinder. The groove on the inner peripheral surface is inclined with respect to the axis of the cylindrical container.

[0008] A method for producing a toner according to the present invention is characterized by using the above-mentioned mechanical pulverizer.

In this case, even if the cylindrical container has the same length as that of the conventional one, the length of the groove becomes longer. Crushability is improved.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a schematic configuration diagram of a mechanical crusher of the present invention. A rotor 2 is rotatably supported on a rotating shaft 5 with a gap inside a cylindrical liner 1. Inside the pulverizer, an air flow is formed for transporting the pulverized material and the pulverized material from the inlet 4 to the outlet 5. The material to be ground taken from the inlet 4 is the rotor 2
Is pulverized by violent eddy currents of air generated by the high-speed rotation of the air, and rises while rotating along the liner 1 and is discharged together with air from the discharge port 5. The gap between the liner 1 and the rotor 2 is usually 1 mm or less, preferably 0.5 to
0.8 mm. If it exceeds 1 mm, the pulverizability of the pulverizer is significantly reduced.

FIG. 2 shows an example of the groove shape of the liner 1 which is a feature of the present invention. FIG. 2 is a partial perspective view showing a groove on the inner peripheral surface of the liner 1 and is formed to be inclined with respect to the vertical direction of the liner 1.

The angle of inclination of the liner 1 with respect to the axis of the groove varies depending on the flow rate of the air flow for transporting the crushed material and the crushed material from the inlet 4 to the outlet 5.
It is preferably inclined at 50 degrees, more preferably at 20 degrees.
~ 40 degrees. If it is less than 10 degrees, the pulverizability deteriorates. If it is more than 50 degrees, the pulverized material becomes clogged in the pulverizer and a large load is applied to the pulverizer. The direction of the inclination of the groove of the liner 1 may be set to either an acute direction or an obtuse angle between the moving direction of the rotor 2 and the direction of the airflow flowing along the groove of the liner 1, In the case of an acute angle direction, the airflow tends to escape, so that it is necessary to set the inclination angle larger than that of the obtuse angle direction in order to obtain the same crushability. For this reason, it is preferable to set the direction to an obtuse angle (the direction of the liner in the figure when the rotation direction of the rotor in FIG. 2 is the direction of the arrow in the figure). The grooves of the rotor 2 may be inclined in the same manner as the liner 1.

Next, in order to explain in detail the cross-sectional shapes of the grooves of the liner 1 and the rotor 2, a straight line A-
FIG. 3 shows an example of a schematic cross-sectional configuration diagram of the liner 1 and the rotor 2 when cut horizontally at A. FIG. 3A shows a case where the cross-sectional shape of the groove of the liner 1 is substantially rectangular and the cross-sectional shape of the groove of the rotor 2 is substantially triangular.
FIG. 3B shows that the cross-sectional shapes of the grooves of the liner 1 and the rotor 2 are both substantially triangular. However, the present invention is not limited to these examples, and a conventionally used cross-sectional shape and a combination thereof can be used. For example, the liner 1 and the rotor 2 can be used.
Can be used, both of which are substantially square.

As described above, since the groove of the liner is inclined, the length of the groove, that is, the crushing area can be lengthened without increasing the size of the liner. The pulverization time of the pulverized toner is increased, and the pulverizability of the toner is improved.

[0015] In this type of mechanical pulverizer, volume pulverization, in which the material to be pulverized is mainly reduced so as to reduce the volume on the upstream side inside the pulverizer, is dominant, and the surface is cut off on the downstream side. Since surface pulverization in which the shape is rounded is dominant, if the groove of the liner is inclined to increase the total length of the groove as in the present invention, the pulverized material is easily rounded.

The mechanical pulverizer of the present invention as described above melt-kneads a mixture containing at least a binder resin and a colorant, cools and solidifies the kneaded material, roughly pulverizes the solidified material, and roughly pulverizes the coarsely pulverized material. It is useful for producing an electrophotographic toner obtained by further pulverizing the coarsely pulverized product. Average particle size about 1000
It is particularly useful for crushing coarsely crushed products having a mean particle size of 10 to 20 µm.

As the binder resin, any binder resin conventionally used in toners can be used. For example, styrene resins, styrene-acryl resins, polyester resins, epoxy resins, and the like, preferably A polyester resin can be used.

The colorant is not particularly limited, and a colorant conventionally used in electrophotography can be used. The following are mentioned.

First, as the black pigment, carbon black, copper oxide, manganese dioxide, aniline black, activated carbon, ferrite, magnetite and the like can be used. Examples of yellow pigments include yellow lead, zinc yellow, cadmium yellow, yellow iron oxide, mineral yellow S, banza yellow G, banza yellow 10G, benzidine yellow G, benzidine yellow GR, quinoline yellow lake, permanent yellow NCG, and tartrazine resin. Heake or the like can be used.

Examples of the red pigment include red lead, molybdenum orange, permanent orange GTR, pyrazolone orange, vulcan orange, indaslen brilliant orange RK, benzidine orange G, indaslen brilliant orange GK, bengala, cadmium red, lead red, permanent Red 4R, Risor Red,
Pyrazolone red, watching red, lake red C, lake red D, brilliant carmine 6B, eosin lake, rhodamine lake B, alizarin lake,
Brilliant Carmine 3B, permanent orange GT
R, Vulcan Fast Orange GG, Permanent Red F4RH, Permanent Carmine FB and the like can be used.

As the blue pigment, navy blue, cobalt blue, alkali blue lake, Victoria blue lake,
Phthalocyanine blue or the like can be used.

The amount of these coloring agents is 1 to 20 parts by weight, preferably 3 parts by weight, per 100 parts by weight of the toner binder resin.
１５15 parts by weight.

The electrophotographic toner that can be produced by using the pulverizer of the present invention includes other desired additives conventionally used in toners, such as charge control agents, anti-offset agents, fluidizing agents, and the like. A release agent, a cleaning agent and the like can be appropriately compounded.

As the charge control agent, those generally used in conventional dry developers can be used. As the positive charge control agent, for example, bontron O3 of nigrosine dye of azine compound, quaternary ammonium Examples of the negative charge control agent include Bontron S-34, a gold-containing azo dye, E-82, an oxynaphthoic acid-based metal complex, and E-82, a salicylic acid-based metal complex.
-84 and phenolic condensate E-89. These amounts are 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight, per 100 parts by weight of the toner binder resin.
0 parts by weight.

As an anti-offset agent, polyethylene wax, polypropylene wax, oxidized polyethylene wax, oxidized polypropylene wax, carnauba wax, sasol wax, rice wax, candelilla wax, jojoba oil wax, beeswax wax, etc. Can be.

The amount of the anti-offset agent added depends on the binder resin 1
The amount is 1 to 7 parts by weight, preferably 2 to 5 parts by weight based on 00 parts by weight. If the amount is less than 1 part by weight, the effect of preventing the offset becomes insufficient, and if it is more than 7 parts by weight, the fluidity of the toner deteriorates.

When a fluidizing agent is used, silica fine particles, titanium dioxide fine particles, alumina fine particles, magnesium fluoride fine particles, silicon carbide fine particles, boron carbide fine particles, titanium carbide fine particles, zirconium carbide fine particles, boron nitride fine particles, titanium nitride fine particles , Zirconium nitride fine particles, magnetite fine particles, molybdenum disulfide fine particles,
Fine particles of aluminum stearate, fine particles of magnesium stearate, fine particles of zinc stearate and the like can be used.

These fine particles are desirably subjected to a hydrophobic treatment with a silane coupling agent, a titanium coupling agent, a higher fatty acid, silicone oil, or the like before use. The amount of the fluidizing agent is 0.05 to 100 parts by weight of the toner.
It is desirable to use 5 parts by weight, preferably 0.1 to 3 parts by weight.

Since the toner obtained by the mechanical pulverizer of the present invention is more rounded than the toner obtained by the conventional mechanical pulverizer, when the toner is put into a developing device and used for image formation, The chargeability of the toner is improved by improving the fluidity of the toner or the developer in the developing device,
There is an advantage that the toner easily moves at the time of development and transfer and the development efficiency and the transfer efficiency are improved.

The mechanical pulverizer of the present invention and a method for producing a toner using the same are described in more detail in the following examples.

[0031]

EXAMPLES (Example 1) 100 parts by weight of styrene acrylic copolymer resin (Mn: 5000, Mn / Mw: 28) 8 parts by weight of carbon black (MA # 8; manufactured by Mitsubishi Chemical Corporation) Nigrosine-based Dye (Nigrosine base EX; Orient Chemical Co., Ltd.) 5 parts by weight ・ Low molecular weight polypropylene (Viscol 550P; Sanyo Kasei Kogyo Co., Ltd.) 2 parts by weight It was kneaded with a machine (made by Ikegai Iron Works). Thereafter, the mixture was cooled with a cooling roller and a cooling conveyor, and coarsely pulverized with a feather mill (manufactured by Hosokawa Micron) to obtain a coarsely pulverized product having an average particle diameter of 2 mm. Then, the liner groove of the rotor rotary pulverizer (KTM0 type; manufactured by Kawasaki Heavy Industries, Ltd.) is inclined by 30 degrees with respect to the axial direction (the direction of the inclination is the moving direction of the rotor and the direction of the air flow flowing along the groove of the liner). In this case, the feed rate of the coarsely pulverized material is fixed at 7 kg / h, the air flow rate of the blower is fixed at 4.5 m 3 / min, and the rotor speed is 8,000. 9000,10000,11000,12
The particle size distribution of the obtained toner particles was measured with a Coulter Counter TAII, and the average particle size of the obtained toner particles was calculated.

The liner 1 and the rotor 2 used at this time have the cross-sectional shape shown in FIG. 3A, and the detailed dimensions are shown below.

Liner dimensions: m ₁ = n ₁ = 4 mm, h ₁ = 3.5 mm Rotor dimensions: m ₂ = 1 mm, n ₂ = 7 mm, h ₂ = 3.
5 mm Gap between both: t = 1 mm (Example 2) The liner groove is inclined by 20 degrees with respect to the axial direction (the direction of the inclination is an obtuse angle between the moving direction of the rotor and the direction of the airflow flowing along the groove of the liner). An experiment was performed in the same manner as in Example 1 except that the orientation was the same as in FIG.

(Example 3) The liner groove is inclined at an angle of 40 degrees with respect to the axial direction (the direction of the inclination is an obtuse angle between the moving direction of the rotor and the direction of the airflow flowing along the groove of the liner). An experiment was performed in the same manner as in Example 1 except that the experiment was performed.

Example 4 An experiment was performed in the same manner as in Example 1 except that the shapes of the toner raw material, the liner, and the rotor were changed as follows.

Raw materials for toner • 100 parts by weight of polyester resin (Mn: 6800, Mw: 86000, gel fraction: 9%) • 8 parts by weight of carbon black (MA # 8; manufactured by Mitsubishi Chemical Corporation) • Cr-containing oil-soluble Dye (Bontron N-01; manufactured by Orient Chemical Industry Co., Ltd.) 2 parts by weight ・ Low molecular weight polypropylene (Viscol TS200P; manufactured by Sanyo Chemical Industry Co., Ltd.) 2 parts by weight Shape of rotor and liner Liner dimensions: m ₁ = 1 mm, n ₁ = 7 mm , H ₁ = 3.
5 mm rotor dimensions: m ₂ = 1 mm, n ₂ = 7 mm, h ₂ = 3.
5 mm Gap between both: t = 1 mm (Comparative Example 1) An experiment was performed in the same manner as in Example 1 except that the liner groove was not inclined with respect to the axial direction.

Table 1 summarizes the average particle diameter of the toner particles obtained in Example 1 to Comparative Example 1.

[0038]

[Table 1]

From the above results, it was clarified that the grindability was improved by inclining the groove of the liner with respect to the axial direction.

Next, in Example 1 and Comparative Example 1, the rotor speed was adjusted to 14.3 μm and 1 μm, respectively.
Table 2 shows the circularity of the 8.5 μm toner obtained. Here, the circularity was determined by measuring the projected area and the projected circumference of the toner, and dividing the circumference of a perfect circle having an area equal to the projected area by the projected circumference. If the projected shape of the toner is a perfect circle, the circularity is 1.

[0041]

[Table 2]

From the results, it was found that the toner was rounded by inclining the groove of the liner with respect to the axial direction.

[0043]

As described above, in the mechanical pulverizer of the present invention, the groove of the liner is inclined, so that the length of the groove, that is, the pulverization area can be lengthened. Therefore, the pulverizability of the object to be pulverized can be improved without increasing the size of the liner. Then, by using this pulverizer, toner can be efficiently produced.

Further, the toner obtained by the mechanical pulverizer of the present invention is more rounded than the toner obtained by the conventional mechanical pulverizer. There are advantages in that the chargeability of the toner is improved by improving the fluidity of the toner or the developer in the developing device, and the toner is easily moved at the time of development and transfer, so that the development efficiency and the transfer efficiency are improved.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a mechanical pulverizer of the present invention.

FIG. 2 is a partial perspective view showing a groove of a liner used in the mechanical pulverizer of the present invention.

FIGS. 3A and 3B are examples of schematic cross-sectional views of a liner and a rotor used in the mechanical pulverizer of the present invention, respectively.

[Explanation of symbols]

 1: liner, 2: rotor

Claims (3)

[Claims] 1. Inside a cylindrical container having a groove on the inner peripheral surface,
A free-rotating cylinder having a groove on the outer peripheral surface is arranged with a predetermined gap from the inner peripheral surface, and crushing is performed by laminar flow and vortex flow of air generated in the gap with rotation of the cylinder. A mechanical pulverizer according to claim 1, wherein a groove on an inner peripheral surface of said cylindrical container is inclined with respect to an axis of said cylindrical container. 2. The mechanical pulverizer according to claim 1, wherein an angle at which the groove on the inner peripheral surface of the cylindrical container is inclined with respect to the axis of the cylindrical container is 10 to 50 degrees. 3. A mixture containing at least a binder resin and a colorant is melt-kneaded, the kneaded product is cooled and solidified, the solidified product is coarsely pulverized to obtain a coarsely pulverized product, and the coarsely pulverized product is further pulverized. 3. A method for producing an electrophotographic toner, wherein the mechanical pulverizer according to claim 1 or 2 is used in a further pulverizing step.