JPH10202192A - Production of air-current classifier and toner for developing static charge image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain the generation of the fusion of particles to be classified and to improve classification precision by a method in which in an apparatus which disperses and classifies the particles with an air current, composite plating coats containing dispersed fine particles are formed on the surface of a member in an air classifier with which the particles collide. SOLUTION: An air-current classifier 1 is equipped with a raw material selection chamber 14, an air current forming means, and a raw material supply nozzle 16. In the chamber 14, three classifying exhaust gas channels 7-9 branched by two classification edges 2, 3, a Coanda block 4, and a back block 5 are opened on its outlet side, and two air introduction channels 11, 12 are opened on its inlet side. A raw material 15 is supplied into the nozzle 16 by a hopper 18, dispersed by compressed air supplied in the nozzle 16, and ejected from the nozzle 16 into a raw material selection chamber 14. On this occasion, composite plating coats 4a, 5a, 21a, 22a, 30a, 31a are formed on the surface of each constitutional member which constitutes channels 7-9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an airflow classifier for injecting a raw material to be classified in which particles having various particle diameters are mixed into an air flow, and classifying the raw material to be classified by particle size utilizing the Coanda effect. And a method for producing a toner for developing electrostatic images using the airflow classifier.

[0002]

2. Description of the Related Art Raw materials that have been finely divided by a pulverizing process are usually in a state of being mixed from coarse particles to very fine particles. When such raw materials are used industrially, it is generally practiced to classify the raw materials after the pulverization treatment and to classify the raw materials according to a particle size in a desired range. The classification is based on the fact that particles moving in a fluid due to gravity, centrifugal force, or inertia force have a difference in sedimentation velocity or particle path according to the particle size, and the particles are classified according to the size of the particle size. For example, in the case of manufacturing a toner for a copying machine, a toner raw material in which particles having various particle diameters are mixed is jetted into an airflow, and a curved linear scattering corresponding to the particle diameter due to the Coanda effect is performed. It is widely applied to airflow classifiers that classify raw materials according to particle size using the descending action.

A conventional air flow classifier is, for example, shown in FIG.
As shown in the airflow classifier 1 shown in FIG. 1, three classification exhaust passages 7, 8, and 9 branched by the classification edges 2 and 3, the Coanda block 4, and the back block 5 are opened on the outlet side, and two A raw material separation chamber 14 in which the inlet channels 11 and 12 are opened on the inlet side, and an airflow forming device (not shown) for generating an airflow flowing from the inlet channels 11 and 12 toward the exhaust channels 7, 8 and 9. (For example, an exhaust fan) and a compressed gas (usually compressed air), and the raw material sorting chamber 14 is used.
Material supply nozzle 1 that feeds and injects material 15 to be classified
6 is provided.

[0004] The raw material to be classified 15 is supplied to the raw material supply nozzle 1 by a hopper 18 communicating with the base end of the raw material supply nozzle 16.
6 and dispersed by the compressed gas 19 supplied to the raw material supply nozzle 16, and pressure-fed and injected from the raw material supply nozzle 16 toward the raw material selection chamber 14 as a solid-gas multiphase flow. At this time, the jets of the classified raw material 15 which are pressure-fed and injected from the raw material supply nozzle 16 into the raw material separation chamber 14 intersect with the air flows from the inlet flow paths 11 and 12 to the respective exhaust flow paths 7, 8 and 9. Therefore, the respective particles of the raw material to be classified 15 are separated into the respective classification exhaust passages 7, 8 and 9 in accordance with the respective particle diameters by a curved linear scattering and falling action corresponding to the particle diameter due to the Coanda effect. Is discharged.

[0005] In the scattered descent action of the curved line due to the Coanda effect, the smaller the particle diameter and the smaller the inertia, the larger the deflection (ie) in the flow direction, and the smaller the particle diameter, the more the exhaust gas is discharged to the classification exhaust passage near the material supply nozzle 16. become. The classification exhaust passages 7, 8 and 9 are arranged such that the classification exhaust passage 7 closest to the Coanda block 4 discharges fine powder, and the classification exhaust passage 9 farthest from the raw material supply nozzle 16 is coarse powder. An exhaust flow path 8 for discharge and for classification which is located in the middle is for discharging medium powder. Classification edge 2
Is for separating fine powder and medium powder, and the classification edge 3 is for separating medium powder and coarse powder.
The raw material to be classified 15 discharged to each of the classification exhaust passages 7, 8 and 9 is supplied to each of the classification exhaust passages 7, 8 and 9 through the pipelines 21, 2 and 9, respectively.
Powder and clean gas (air) are separated by a dust collector (not shown) connected via 2 and 23.

In the airflow classifier 1, the surface of the member in the airflow classifier 1 against which the particles of the raw material 15 flying at a high speed collide is worn by friction with the particles of the raw material 15 to be classified. The abrasion due to the collision of the particles of the raw material to be classified 15 is particularly remarkable at the front end portions of the classification edges 2 and 3 and the surface of the back block 5 arranged opposite to the raw material supply nozzle 16. Usually, the sharp edges of the classification edges 2 and 3 are important factors influencing the classification accuracy, and are accurately positioned before the operation of the apparatus. When the front end is worn, the sorting performance by the front end is reduced, and the classification accuracy is lowered. Therefore, the classification edges 2 and 3 where the wear has advanced over a certain level
In order to prevent the abrasion of the classifying edge, conventionally, the surface of the classifying edges 2 and 3 made of stainless steel or the like is coated with tungsten carbide having high hardness and excellent wear resistance. And other measures were taken.

On the other hand, recently, as the copying speed of the copying machine has been increased and the power consumption has been reduced, the number of copying machines using a so-called low melting point toner has been increasing. The low-melting-point toner uses a synthetic resin that forms a part of the toner for a copying machine, for example, a styrene-acrylic acid copolymer having a low glass transition point of 40 to 70 ° C. and a low molecular weight to suppress the melting point of the toner. It is a thing. Since the particles of the low melting point toner have a soft hardness, the burden on the members of the airflow classifier 1 during the classifying process is small.

However, when the low-melting-point toner is classified, there are the following problems. That is, at the time of the classification process, the fusion of the toner particles is likely to occur on the surface of the member in the airflow classifier 1 where the particles of the material to be classified 15 collide, particularly on the tip portions of the classification edges 2 and 3. Then, the fusion of the low melting point toner to the end portions of the classification edges 2 and 3 is performed as follows.
The width of the front end portion of the classification edge is widened to reduce the sorting performance, thereby lowering the classification accuracy. Therefore, the fusion must be removed before the fusion becomes noticeable. In order to remove the fused material, it is necessary to stop the operation of the airflow classifier 1 and appropriately perform disassembly, replacement, cleaning, and the like, which causes a problem that the operation rate of the apparatus is greatly reduced.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems and achieve the following objects. That is, even when the particles of the raw material to be classified are low-melting toner or the like, the particles of the raw material to be classified are less likely to be fused to the surface of the member in the airflow classifier where the particles of the raw material to be classified collide. As a result, the air flow classifier is stopped to remove the cohesive material, and there is no need to disassemble, so that the equipment operation rate and productivity can be improved, the classification accuracy is improved, and the advanced classification is performed. An object of the present invention is to provide an airflow classifier capable of maintaining accuracy for a long period of time, and a method of manufacturing a toner for developing an electrostatic image using the airflow classifier.

[0010]

Means for Solving the Problems The present invention is based on the fact that the inventors of the present invention have conducted various experiments and made intensive studies, and as a result obtained the following findings. That is, when the material to be classified in the airflow classifier that performs classification using the Coanda effect is a low-melting toner or the like, the particles of the material to be classified adhere to the surface of the member in the airflow classifier where the particles of the material to be classified collide. The phenomenon of fusing is due to the Scottnicky effect in which a low-melting synthetic resin flying at a high speed collides with the surface of a member in the airflow classifier due to collision energy and adheres.
It is a finding that, when a composite plating film containing specific fine particles dispersed therein is provided on the surface of a member in an airflow classifier, the occurrence of a phenomenon in which the particles of the raw material to be classified are effectively fused can be suppressed.

The means for solving the above-mentioned problems are as follows. That is, <1> in an airflow classifier that disperses and classifies particles using an airflow, a composite plating film containing fine particles dispersedly provided is provided on the surface of a member in the airflow classifier where particles of the material to be classified collide. It is an airflow classifier characterized by the following. <2> A plurality of classifying exhaust channels branched by the classifying edge are opened on the outlet side, and an inlet channel is provided on the inlet side for the raw material separation chamber, and from the inlet channel to each classifying exhaust channel. Airflow forming means for generating an airflow flowing toward the source material, and pressurizing / feeding the material to be classified into the material separation chamber using a compressed gas.
A raw material supply nozzle for injecting, and the particles of the raw material to be classified, which are pressure-fed and injected into the raw material selection chamber from the raw material supply nozzle, each have a curved linear scattering and falling action corresponding to the particle diameter due to the Coanda effect. The airflow classifier according to <1>, wherein the airflow is classified into an exhaust passage for classification. <3> The airflow classifier according to <1> or <2>, wherein the fine particles have a volume average particle size of 2 μm or less. <4> The inner wall of the raw material separation chamber, the outer wall of the classification edge, and the exhaust flow path for classification, in which the surface of the member in the airflow classifier collides with the particles of the raw material to be classified, which are fed and injected from the raw material supply nozzle. <2> or <3>, which is the inner wall of
The airflow classifier described in 1. <5> The airflow classifier according to any one of <1> to <4>, wherein a contact angle of the composite plating film with water by a droplet method is 100 ° or more. <6> The above-mentioned item <1>, wherein the fine particles are fine particles of a fluorine compound.
> To <5>. <7> The air classifier according to any one of <1> to <5>, wherein the fine particles are fine particles of two or more fluorine compounds. <8> wherein the fluorine compound is selected from fluororesin, fluorinated graphite {(CF) n} and fluorinated pitch
An airflow classifier according to <6> or <7>. <9> the fluororesin is polytetrafluoroethylene,
The above <8> selected from a tetrafluoroethylene-hexafluoropropylene copolymer and a tetrafluoroethylene-perfluoroalkylvinyl ether copolymer
The airflow classifier described in 1. <10> The airflow classifier according to any one of <1> to <9>, wherein the composite plating film is heat-treated at 150 to 300 ° C.

<11> a step of preparing a kneaded material by melt-kneading the binder resin and the colorant, a step of pulverizing the kneaded material to prepare a pulverized product, and removing the pulverized product from the above <1><1
A method for producing a toner for developing an electrostatic charge image, comprising a step of classifying using the airflow classifier according to any one of <1> to <7>. <12> The above <11>, wherein the binder resin is polyester.
4. The method for producing a toner for developing an electrostatic charge image according to (1). <13> The glass transition point of the electrostatic image developing toner is 50
The method for producing an electrostatic image developing toner according to <11> or <12>, wherein the temperature is from 65 to 65 ° C. <14> The method for producing an electrostatic image developing toner according to any one of <11> to <13>, wherein the electrostatic image developing toner has a softening point of 120 ° C. or lower. <15> The method for producing an electrostatic image developing toner according to any one of <11> to <14>, wherein the electrostatic image developing toner has an average particle diameter of 9 μm or less.

In the present invention, a composite plating film having an extremely low adhesion to a low melting point toner or the like as compared with a conventional film of tungsten carbide or the like is formed on the surface of a member in the airflow classifier where particles of the material to be classified collide. Provided.
Therefore, even if particles of the material to be classified collide with the surface of the member in the airflow classifier and are fused by heat generated from collision energy at that time, particles of the material to be classified collide thereon. Then, the particles of the material to be classified are easily separated from the members in the airflow classifier. As a result, even if the airflow classifier is continuously operated, the particles of the raw material to be classified hardly accumulate on the surfaces of the members in the airflow classifier.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The air classifier of the present invention will be described in detail below. The airflow classifier of the present invention includes at least an airflow forming unit, a raw material supply nozzle, and a raw material selection chamber, and may further include a unit appropriately selected as needed.

The air flow forming means has a function of generating an air flow flowing from the air inlet flow path to each of the classifying exhaust flow paths. There is no particular limitation on the shape, structure, size, etc. of the airflow forming means as long as it has the function,
It can be selected from those known per se, and examples thereof include those having a blower such as a fan and a pipe for guiding an air flow from the blower.

The raw material supply nozzle has a function of feeding and injecting the raw material to be classified into the raw material separation chamber by using a compressed gas. The raw material supply nozzle is not particularly limited in its shape, structure, size, etc., as long as it has the function,
Although it can be selected from those known per se, for example, a hopper for supplying particles of the material to be classified, a blowing means such as a fan for generating an air flow for pressure-feeding / injecting the particles of the material to be classified, and the blowing means And a tube for guiding the particles of the raw material to be classified.

The raw material sorting chamber has a function of causing the particles of the raw material to be classified, which are fed and injected from the raw material supply nozzle, to scatter and fall in a curved line shape corresponding to the particle size due to the Coanda effect. The raw material sorting chamber is not particularly limited in its shape, structure, size, etc., as long as it has the function, and can be selected from those known per se.For example, the raw material supply nozzle is connected, and For example, a raw material sorting chamber having a structure in which a plurality of branched exhaust passages for classification are opened on the outlet side and an inlet passage is opened on the inlet side. In the present invention, in the raw material separation chamber, an air flow flowing from the air inlet flow path to the classification exhaust flow path intersects an air flow that is pressure-fed and injected from the raw material supply nozzle together with the particles of the raw material to be classified. The inlet channel, the classifying exhaust channel, the source supply nozzle, and the like are connected to the source separation chamber. Then, at the time of this connection, the Coanda block is arranged below the raw material supply nozzle, so that the raw material supply nozzle feeds and feeds the raw material into the raw material sorting chamber.
The injected particles of the classifying raw material scatter and fall down in a curved line shape corresponding to the particle size due to the Coanda effect.

The classification edge is disposed on the outlet side of the raw material sorting chamber and has a function of branching a space on the outlet side of the raw material sorting chamber. The classification edge is not particularly limited in its shape, structure, size, and the like as long as it has the function, and can be selected from those known per se, but, for example, an arbitrary one in which one plane exists on the plane Bending along a straight line, and the shape which makes this straight line the edge front-end | tip is mentioned. Generally, the classification edge is
In the present invention, a space sandwiched between the outer surface of the flat surface and the outer wall of the Coanda block corresponds to the exhaust passage for classification. The classification edge may be fixedly arranged in the airflow classifier or may be detachably arranged, but the latter is more convenient for maintenance and inspection.

In the present invention, a composite plating film containing fine particles dispersed therein is provided on the surface of the member in the airflow classifier. By combining such fine particles with a metal, it is possible to obtain a composite plating film having both the excellent properties inherent to the fine particles and the properties of the metal,
As a result of providing the composite plating film on the surface of the member in the airflow classifier, the above object can be achieved.

The surface of the member in the airflow classifier may be the entire surface or a part of the surface of the member in the airflow classifier. In the present invention, the surface of the member in the airflow classifier is used. It is preferable that the surface of the member be subjected to the collision of the particles of the material to be classified, which is pressure-fed and injected from the material supply nozzle, and further, the material selection that is frequently subjected to the collision of the particles of the material to be classified. More preferably, the inner wall of the chamber, the outer wall of the classification edge, and the inner wall of the exhaust passage for classification.

The fine particles are not particularly limited as long as they have low adhesion to the powder of the raw material to be classified. Among them, in the present invention, the self-lubricating property, low friction property, water repellency and water repellency are used. Fluorine compound fine particles having excellent properties such as oiliness and non-adhesiveness are particularly preferred.

The fluorine compound is not particularly limited and may be appropriately selected depending on the intended purpose.
Preferable examples include fluorinated graphite, fluororesin, and fluorinated pitch. All of these fluorine compounds are known, and there are no particular restrictions on the raw materials, production methods, and the like,
It may be appropriately synthesized or a commercially available product may be used.

The fluorinated graphite is a polycarbon monofluoride (represented by the general formula (CF) n). The fluorinated graphite is not particularly limited and may be selected from those known per se. However, in the present invention, it is preferable that n> 1000 in the general formula.
The fluorinated graphite may be appropriately synthesized or a commercially available product may be used.

The fluororesin is not particularly limited and can be selected from those known per se. Examples thereof include polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkylbiphenyl ether copolymer (PFA), And tetrafluoroethylene-hexafluoropropylene copolymer (FEP). As the fluororesin, an appropriately synthesized one or a commercially available product may be used.

The fluorinated pitch generally has a layered structure in which aromatic condensed six-membered ring planes are laminated, and has a structure in which aromatics constituting the six-membered ring planes are crosslinked by an aliphatic hydrocarbon group such as methylene. Have. The fluorinated pitch is not particularly limited and can be selected from those known per se. An appropriately synthesized one may be used, or a commercially available product may be used. An example of the production of the fluorinated pitch is disclosed in, for example, JP-A-62-275190, and can be obtained by fluorinating the pitch using fluorine gas.

As a raw material for producing the pitch fluoride, for example, petroleum distillation residue, naphtha pyrolysis residue, ethylene bottom oil, coal liquefied oil, petroleum heavy oil such as coal tar and the like are distilled to obtain a boiling point of 200. Pitch from which low-boiling components lower than 0 ° C. have been removed, and pitch obtained by heat-treating and / or hydrogenating this pitch. More specifically, pitch as a raw material for producing fluorinated pitch includes, for example, isotropic pitch, mesophase pitch, hydrogenated mesophase pitch, and distillation of petroleum or coal heavy oil to remove low boiling components. And mesocarbon microbeads composed of mesophase spheres formed after the formation.

The fluorinated pitch can be obtained, for example, by reacting the above-mentioned raw material pitch with fluorine at about 0 to 350 ° C. Examples of the method for producing the pitch fluoride include a method of directly reacting the raw material pitch with the fluorine gas at a temperature of about 0 to 350 ° C. In the method, a preferred temperature for reacting the pitch with the fluorine gas is a temperature equal to or lower than the softening point of the pitch. The fluorine gas pressure during the reaction is not particularly limited, but is generally in a range of 0.07 to 1.5 atm. In the reaction, the fluorine gas may be used as it is, or may be used after being diluted with an inert gas such as nitrogen, helium, argon, or neon.

The obtained fluorinated pitch substantially consists of carbon atoms and fluorine atoms, and the F / C atomic ratio is, for example, about 0.5 to 1.8. The fluorinated pitch has the following characteristics. That is, in (a) powder X-ray diffraction, a peak of the maximum intensity is shown around 2θ = 13 °, and 2θ
A peak having an intensity smaller than the above peak is shown at around = 40 °. (B) In X-ray photoelectron spectroscopy analysis, 290.0
The peak corresponding to the CF group at ± 1.0 eV and 292.5
Shows a peak corresponding to a CF ₂ group around ± 0.9 eV,
The ratio of the intensity of the peak corresponding to the CF ₂ group to the peak corresponding to the CF group is about 0.15 to 1.5.
(C) The film can be formed by vacuum evaporation.
(D) The contact angle with water at 30 ° C. is 141 ± 8.
°.

The fluorinated pitch is a white to yellow-white or brown solid, and is a very stable compound having excellent water resistance and chemical resistance. Furthermore, the fluorinated pitch is
It can also be obtained in the form of a transparent resin. The pitch of such a transparent resinous fluoride pitch may be, for example, about 0.1 to 3 ° C./min, preferably about 0.5 to 1.5 ° C./min, in a fluorine gas-containing atmosphere. 250-40 by speed
It can be obtained by raising the temperature to about 0 ° C. and reacting for a predetermined time, for example, about 1 to 18 hours, preferably about 6 to 12 hours. The properties of the transparent resinous pitch fluoride include, for example, an atomic ratio (F / C) of 1.5 to 1.
7 and a light transmittance (250 to 900 nm) of 90
% Or more, the molecular weight is about 1500 to 2000, and the softening point is about 150 to 250 ° C.

In the present invention, the fine particles of the fluorine compound may include only a single type of fine particles, or may include a plurality of types of fine particles. In other words, the fluorine compound may be used alone or
Two or more kinds may be used in combination. In the latter case, the mixing ratio of the fine particles of a plurality of types of fluorine compounds used in combination is not particularly limited, and can be arbitrarily selected as appropriate.

When a plurality of fine particles of a fluorine compound are used, the combination of the fine particles of a fluorine compound is not particularly limited and can be appropriately selected according to the purpose. Preferred examples thereof include fine particles of fluorinated graphite. And fluorinated pitch fine particles (2 types), fluorinated graphite fine particles and P
Combination with TFE fine particles (2 types), Combination of fluorinated graphite fine particles and PFA fine particles (2 types), Combination of fluorinated graphite fine particles and FEP fine particles (2 types), Combination of pitch fluoride fine particles and PTFE fine particles (2 types), combinations of pitch fluoride fine particles and PFA fine particles (2 types), combinations of pitch fluoride fine particles and FEP fine particles (2 types), combinations of PTFE fine particles and PFA fine particles (2 types), PTFE fine particles (2 types), PFA fine particles and FEP fine particles (2 types), fluorinated graphite fine particles, pitch fluoride fine particles and PTFE fine particles (3 types)
Species), fluorinated graphite fine particles, fluorinated pitch fine particles and PFA
Combination with fine particles (3 types), combination of graphite fluoride particles, pitch fluoride particles and FEP particles (3 types), combination of graphite fluoride particles, PTFE particles and PFA particles (3 types), graphite fluoride Fine particles and PTFE fine particles and FE
Combination with P fine particles (3 types), fluorinated graphite fine particles and PF
Combination of A fine particles and FEP fine particles (3 types), combination of pitch fluoride fine particles, PTFE fine particles and PFA fine particles (3 types), pitch fluoride fine particles, PTFE fine particles and FE
Combination with P fine particles (3 types), pitch fluoride fine particles and P
Combination of FA fine particles and FEP fine particles (3 types), PTF
Combination of E fine particles, PFA fine particles and FEP fine particles (3
Species), fluorinated graphite fine particles, fluorinated pitch fine particles and PTF
Combination of E fine particles and PFA fine particles (4 types), graphite fluoride fine particles, pitch fluoride fine particles, PTFE fine particles and FE
Combination with P fine particles (4 types), Combination of fluorinated graphite fine particles, pitch fluoride fine particles, PFA fine particles and FEP fine particles (4 types), Fluorinated graphite fine particles, PTFE fine particles and PF
Combination of A fine particles and FEP fine particles (four types), graphite fluoride fine particles, pitch fluoride fine particles, PTFE fine particles and FE
Combinations (5 types) of P fine particles and PFA fine particles are exemplified.

In the present invention, among these combinations, the combination of fluorinated graphite fine particles and PTFE fine particles (2
Species), a combination of fluorinated graphite fine particles and PFA fine particles (2
Species), a combination of fluorinated graphite fine particles and FEP fine particles (2
Species), combinations of pitch fluoride fine particles and PTFE fine particles (two types), combinations of pitch fluoride fine particles and FEP fine particles (two types), combinations of pitch fluoride fine particles and PFA fine particles (two types), PTFE fine particles And the combination of PFA fine particles (two types) and the combination of PFA fine particles and FEP fine particles (two types) are preferable.

When one kind of the fluorine compound fine particles is used alone, the fluorine compound fine particles are preferably pitch fluoride fine particles, PTFE fine particles, PFA fine particles and the like.

When fine pitch fluoride particles are used alone as the fine particles of the fluorine compound, or when pitch fine fluoride particles are used in combination with other fluorine compound fine particles, a high-performance composite plating film can be obtained. The water repellency of the surface of the composite plating film is about 100 to 135 ° as a contact angle in a droplet method using water.

In the present invention, the metal plating solution used as a salt in the form of a salt and serving as a matrix in the composite plating film is not particularly limited, and may be appropriately selected from those known per se according to the purpose. Can be, for example, nickel, copper, zinc, tin, iron, lead, cadmium,
Examples include a plating solution containing chromium, precious metals, and alloys thereof.

As a method for forming the composite plating film on the surface of the member in the airflow classifier, a known electroless plating method or electrolytic plating method capable of depositing a matrix metal on the surface of a metal material is suitably employed. can do.
Also, the plating solution to be used can be appropriately selected and used from plating solutions of various known compositions,
Specifically, for example, according to a plating method disclosed in JP-A-49-27443, JP-A-4-329897, etc., the fine particles are dispersed in an aqueous solution of a plating metal salt, and the air current classification is performed. It can be carried out by co-depositing the fine particles together with the matrix metal on the surface of a member in the machine. The composite plating film thus formed has both the inherent properties of the non-metallic fine particles and the properties of the matrix metal.

In the present invention, the particle size of the fine particles to be added to a plating solution for forming a composite plating film (hereinafter, referred to as a composite plating solution) is not particularly limited. If the particle size is large, the fine particles fall off from the surface of the formed composite plating film due to friction. Therefore, the particle size is preferably smaller than the thickness of the composite plating film to be formed. The thickness of the composite plating film varies depending on the material and shape of the members in the airflow classifier, the type of the matrix metal, and the like, and cannot be specified unconditionally, but is generally about 1 to 50 μm. Accordingly, the particle size of the fine particles may be determined in consideration of the thickness of the composite plating film, but usually, the volume average particle size is about 2 μm or less, and more preferably 1 μm or less. Further, in order to ensure the uniformity of dispersion of the fine particles in the composite plating solution and the composite plating film, 30
It is preferable not to contain coarse particles of μm or more.

The addition amount of the fine particles in the composite plating solution is not particularly limited, but is usually about 200 g / l or less, preferably about 1 to 100 g / l. Generally, in a composite plating film composed of a metal and an eutectoid, as the volume fraction of the eutectoid increases, the adhesion between the composite plating film and the substrate on which the composite plating film is provided decreases. Also in the present invention, the volume fraction of eutectoids (the fine particles) in the composite plating film is at most 60% in consideration of the adhesion between the composite plating film and the base member in the airflow classifier. Is the limit. On the other hand, when the volume fraction of the fine particles is too low, the water repellency is not sufficiently improved. Therefore, in the present invention, the volume fraction of the fine particles in the composite plating film is usually 25 to 25. It is about 50%, preferably about 35 to 45%.

In the composite plating solution, it is necessary to uniformly disperse a fluorine compound or the like having extremely high water repellency in the plating solution and to make the plating solution completely wet. Therefore, it is preferable to use a surfactant. . As the surfactant, for example, a water-soluble cationic surfactant, a nonionic surfactant, and an amphoteric surfactant showing cationicity at the pH value of the composite plating solution can be used. Examples of the cationic surfactant include quaternary ammonium salts, those of secondary and tertiary amines, and the like. Examples of the nonionic surfactant include polyethyleneimine-based and ester-based surfactants. Things.
Examples of the amphoteric surfactant include carboxylic acid-based surfactants,
Sulfone type and the like can be mentioned. Among these,
Fluorinated surfactants having a CF bond in the molecule are particularly preferred.

The amount of the surfactant to be added to the composite plating solution is, for example, usually 1 to 1 g of the fluorine compound when the fine particles are fine particles of a fluorine compound.
It is about 100 mg, more preferably about 1 to 50 mg.

In the present invention, the composite plating solution contains
Known additives such as a primary brightener, a secondary brightener, and a pigment for coloring a coating film can be appropriately added according to the purpose.

In forming the composite plating film, it is preferable to perform a plating operation while stirring the composite plating solution to uniformly disperse the fine particles.
The stirring method is not particularly limited, and a mechanical stirring method known per se, for example, a screw stirring method, a stirring method using a magnetic stirrer, or the like can be employed.

The plating conditions for forming the composite plating film include the material of the member in the airflow classifier as the base material,
It differs depending on the type of the composite plating solution to be used, etc., and cannot be specified unconditionally, and may be appropriately determined according to the purpose, but the same solution temperature and pH as in the case of the ordinary composite plating method
Value, current density, etc. can be adopted.

In the present invention, the composite plating film may be formed directly on the surface of a member in the airflow classifier, or may be a known base plating layer (for example, formed on the surface of a member in the airflow classifier). , Nickel plating, copper plating, etc.), and then may be formed on the base plating layer.

In the present invention, the composite plating film formed on the surface of the member in the airflow classifier may be used in the range of 150 to 35.
Heat treatment at 0 ° C. is preferred. If the temperature of the heat treatment is lower than 150 ° C., it is necessary to lengthen the time of the heat treatment in order to obtain a sufficient effect, while if it exceeds 350 ° C., the composite plating film may be deteriorated.

The heat treatment significantly improves the durability and surface water repellency of the composite plating film. In particular, it is effective when using fine pitch fluoride particles or fine pitch fluoride particles and PTFE fine particles and / or FEP fine particles as the fine particles. By this heat treatment, for example,
When using pitch fluoride fine particles alone,
The contact angle of the composite plating film by water in a droplet method is 135.
° or even 145 °, which is considered to be the measurement limit of the water droplet method. In addition, when the pitch fluoride fine particles and the PTFE fine particles and / or the FEP fine particles are used in combination, the contact angle becomes 120 ° or more.

It is not clear why the heat treatment significantly improves the water repellency, but the wettability due to the thermal modification of the composite plating film itself and the removal of the surfactant (by thermal decomposition, evaporation, sublimation, etc.). It is inferred that the decline in the number of people also contributed to this. Although the time of the heat treatment is not particularly limited, it is generally about 10 to 30 minutes.

The particles of the raw material to be classified in the airflow classifier of the present invention are not particularly limited and can be appropriately selected according to the purpose. For example, toner particles are preferred. In the airflow classifier of the present invention described above, since the members in the airflow classifier on which the composite plating film is formed are formed of a material having appropriate rigidity and the like,
Even when the airflow or the particles of the material to be classified collides, the attitude of the surface of the members in the airflow classifier and the installation position are not significantly displaced, and the flow of the particles of the material to be classified which is flying is controlled well. Can be. Further, the composite-plated member is provided on a wide surface of the member in the airflow classifier, specifically, on a wide surface such as an inner wall of the raw material sorting chamber, an outer wall of the classification edge, and an inner wall of the exhaust passage for classification. By providing, the fusion and deposition of the particles of the classifying raw material can be effectively prevented. The airflow classifier of the present invention can be suitably used for classification of various powders in a wide field,
In particular, it can be suitably used in the following method for producing a toner for developing an electrostatic image of the present invention.

The process for producing a toner for developing an electrostatic image of the present invention comprises the steps of melt-kneading a binder resin and a colorant to prepare a kneaded product, pulverizing the kneaded product to prepare a pulverized product, And at least a step of classifying the pulverized product using the airflow classifier of the present invention. Further, other steps can be included as necessary.

In the method for producing a toner for developing an electrostatic image of the present invention, there is no particular limitation on other points as long as the airflow classifier of the present invention is used for classifying toner particles. It can be performed according to the method.
The method for producing the toner, the raw material of the toner, and the like are described in, for example, JP-A-8-278655 and JP-A-8-30.
The details are described in, for example, Japanese Patent Application Laid-Open No. 5080 and Japanese Patent Application Laid-Open No. Hei 8-305083, which can be referred to.

In the method for producing a toner for developing an electrostatic image of the present invention, the binder resin of the toner for developing an electrostatic image is preferably polyester. When the binder resin is a polyester, the structure includes -OH groups, -COO
The resin may contain a polar group such as an H group, and may have a polarity in a portion other than the terminal structure such as a polar group. This resin has a very strong electrostatic interaction. Therefore,
Fusing to the inner wall of the apparatus is also easy to occur, and the function of the present invention works effectively. Further, the glass transition point of the obtained toner for developing an electrostatic image is preferably 50 to 65 ° C. When the glass transition point is 50 to 65 ° C., the function of the present invention works effectively because heat generated by collision with the inner wall easily causes fusion to the inner wall. If the temperature is lower than 50 ° C., it is not practical because it is difficult to handle the toner. Further, the softening point of the obtained toner for developing an electrostatic image is preferably 120 ° C. or less. When the softening point is 120 ° C. or lower, the function of the present invention works effectively because fusion generated on the inner wall is easily caused by heat generated by collision with the inner wall. Further, the average particle diameter of the obtained electrostatic image developing toner is preferably 9 μm or less. When the average particle diameter is 9 μm or less, the cohesion between particles and the adhesion to the inner wall are relatively higher than the gravity and the applied wind force, and the particles are easily adhered. Therefore, the function of the present invention works effectively. According to the method for producing a toner for developing an electrostatic image of the present invention, a method for producing a toner for developing an electrostatic image having a constant particle size distribution can be obtained easily, simply, and efficiently.

[0052]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic cross-sectional view for explaining one embodiment of the airflow classifier of the present invention. The airflow classifier 1 shown in FIG. 1 includes a raw material sorting chamber 14, an airflow forming means (for example, an exhaust fan) not shown, and a raw material supply nozzle 16. The raw material sorting room 14 has two classification edges 2
And 3, Coanda block 4, and back block 5
Exhaust passages 7, 8 and 9 branched by
Are opened at the outlet side, and the two inlet channels 11 and 12
Is set up at the entrance side. The airflow forming means,
An airflow is generated that flows from the inlet channels 11 and 12 to the respective classifying exhaust channels 7, 8 and 9. Raw material supply nozzle 1
6 feeds and injects particles of the raw material to be classified 15 into the raw material sorting chamber 14 using a compressed gas (normally, compressed air).

The material to be classified 15 is supplied to the material supply nozzle 1 by a hobber 18 communicating with the base end of the material supply nozzle 16.
6 and dispersed by the compressed gas 19 supplied to the raw material supply nozzle 16, and is injected from the raw material supply nozzle 16 into the raw material selection chamber 14 as a solid-gas multiphase flow. The jet of the classified raw material 15 injected from the raw material supply nozzle 16 into the raw material sorting chamber 14 has an inlet passage 11.
And 12 intersect with each other in the air flow toward each of the classification exhaust passages 7, 8 and 9, so that each particle of the raw material to be classified 15 is affected by a curved linear scattering and falling action corresponding to the particle diameter due to the Coanda effect. Are discharged separately to the classification exhaust passages 7, 8 and 9. In the curved linear scattering-down action by the Coanda effect, the smaller the particle size, the greater the deflection (ie) in the flow direction, and the particles are discharged to the classifying exhaust flow path closer to the raw material supply nozzle 16.

Regarding the exhaust passages 7, 8 and 9 for classification,
The classifying exhaust channel 7 closest to the Coanda block 4 is for discharging fine powder, and the classifying exhaust channel 9 farthest from the raw material supply nozzle 16 is for coarse powder discharging and located in the middle. The classification report exhaust passage 8 is for discharging the medium powder. Further, the classification edge 2 is for separating fine powder and medium powder,
The classification edge 3 is for separating medium powder and coarse powder. The particles of the raw material to be classified 15 discharged to the respective classification exhaust passages 7, 8 and 9 are combined with the respective classification exhaust passages 7, 8.
And 9 are separated into powder and clean gas (air) by a dust collector (not shown) connected via conduits 21, 22 and 23.

In the airflow classifier 1 described above, a material such as stainless steel, which has higher hardness than at least the particles of the material to be classified 15, where the particles of the material to be classified 15 colliding with the material supplied from the material supply nozzle 16 collides. The surface of a member in the airflow classifier 1 having sufficient rigidity that does not bend due to the airflow flowing into the raw material sorting chamber 14 or the collision of particles of the raw material to be classified 15 contains dispersed fluorine compound fine particles of 2 μm or less. A composite plating film is provided.

The composite plating film formed on the surface of the members in the airflow classifier 1 is, for example, a composite plating film formed on the surface of the classification edge 2 which constitutes the exhaust passage 7 for classification. 2a, composite plating film 30a formed on the surface of classification edge mounting base 30, and Coanda block 4
Is the composite plating film 4a formed on the surface of the substrate. Also,
The composite plating film 5a formed on the surface of the rear block 5, the composite plating film 3a formed on the surface of the classification edge 3, and the surface of the classification edge mounting base 31 constituting the exhaust passage 9 for classification. This is the composite plating film 31a. In addition, the classification edge 2 constituting the classification exhaust passage 8
A composite plating film 2a formed on the surface of the composite plating film 30a formed on the surface of the classification edge mounting base 30;
A composite plating film 3a formed on the surface of the classification edge 3;
And a composite plating film 31a formed on the surface of the classification edge mounting base 31. Further, the composite plating film 16a formed on the inner peripheral surface of the raw material supply nozzle 16, the exhaust passage 7,
Lines 21, 22, and 23 respectively connected to 8 and 9
Are the composite plating films 21a, 22a, and 23a formed on the inner peripheral surface. The surface roughness of these composite plating films was set so as to have the same smoothness as the surface of tungsten carbide attached to the classification edge surface in a conventional airflow classifier.

FIG. 2 is an enlarged schematic sectional view of the classification edge 2 of the airflow classifier 1 shown in FIG. The case of the classification edge 3 is the same as that of FIG. In the classification edges 2 and 3, the narrow angle θ formed by the inclined surfaces on both sides provided to the inner walls of the classification exhaust passages 7, 8 and 9 is set to 23 °.

Here, using an airflow classifier 1, magenta toner having an average particle diameter of 7 μm pulverized by the following composition and production method is used as particles of the material to be classified 15, and the magenta toner is classified. A toner was manufactured.

Linear polyester resin: 100% by weight (linear polyester obtained from terephthalic acid / bisphenol A / ethylene oxide adduct / cyclohexane dimethanol; Tg = 62 ° C., Ts = 110 ° C., Mn = 4,000, Mw = 35,000, acid value = 12, hydroxylation = 25) Magenta pigment (CI Pigment Red 57) 3% by weight This is a magenta toner obtained by kneading the mixture with an extruder and pulverizing with a jet mill.

The conditions for the classification are as follows. The compressed air for pressure-feeding / injecting the raw material to be classified 15 from the raw material supply nozzle 16 has a pressure of 3 kgf / cm ² G and a flow rate of 0.47 g / cm ² G.
Nm ³ / min. In addition, the flow rate of the airflow flowing from the inlet channels 11 and 12 to the classifying exhaust channels 7, 8 and 9 is as follows:
The amount of suction air from the exhaust passages 7, 8 and 9 for classification is 11
Nm ³ / min. The raw material to be classified 15 was continuously supplied at a rate of 30 kg / h.

The composite plating film is formed as follows.
Formed. (Preparation of plating solution) Fluorine compound fine particles shown in Table 1
% Was added to a nickel electrolytic bath having the following composition:
In addition, surfactant (trademark “MegaFac F150”, large
Nippon Ink Chemical Co., Ltd., 3rd grade perfluoroammonium
Um salt (C₈F₁₇SO_TwoNH (CH _Two )_ThreeN⁺(C
H_Three)_Three・ Cl^-)) Per 40 g of the fluorine compound.
0 mg was added.

(Nickel sulfamate electrolytic bath composition) Nickel sulfamate 350 g / l Nickel chloride 45 g / l boric acid 40 g / l

A member in the airflow classifier for forming the composite plating film was used as a negative electrode, and the thickness was 1 to 3 μm using a wood bath having the following composition at a liquid temperature of 25 ° C. and a current density of 10 A / dm ^2. The underlayer nickel plating film was formed.

(Wood bath composition) Nickel chloride 245 g / l Hydrochloric acid・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 120g / l

Then, a liquid temperature of 45 ± 5 ° C., a pH of 3.8 to 4.2, and a current density of 3 A / dm ² were applied on the underlying nickel plating film of the members in the airflow classifier on which the underlying nickel plating film was formed. Electrolytic plating was carried out under a condition and with screw stirring until the film thickness became 10 μm, to form a nickel-fluorine compound composite plating film.

Each of the members on which the obtained nickel-fluorine compound composite plating film was formed was subjected to a heat treatment under the conditions shown in Table 1 in a hot air circulating drying oven, and then left at room temperature for 1 hour at room temperature. Kaku meter (Kyowa Science Co., Ltd .: C
(A-A type), the contact angle of water was measured by a droplet method, and its water repellency was examined. Table 1 shows the measurement results of the contact angles.

A comparative experiment was performed as described above except that the composite plating film was replaced with a conventional tungsten carbide film, and a comparative experiment was performed as described above except that the composite plating film was replaced with a conventional polyurethane resin film. A comparative experiment was performed. The results are also shown in Table 1.

[0068]

[Table 1]

Table 1 clearly shows the following from the results. 3 for conventional tungsten carbide coatings
At the time of continuous operation, particles were fused on both inclined surfaces of the classification edge 2. In the case of the polyurethane resin coating, particles fused to both inclined surfaces of the classification edge 2 at the time of continuous operation for 8 hours. On the other hand, in the case of the composite plating film, no fusion of the toner particles as the raw material to be classified was observed at all even after continuous operation for 24 hours.

In the air classifier 1 of the present invention, the raw material to be classified 1
5 has a configuration in which the surface of the member in the airflow classifier 1 on which the particles 5 collide is much lower in adhesion force than a member such as a conventional tungsten carbide. Even if the particles of the material to be classified 15 are fused by the heat generated by the collision energy at the time of colliding with the surface of the member in the machine 1, the particles of the material to be classified 15 may collide thereon. Thus, the particles of the raw material to be classified 15 are easily separated from the surface of the member in the airflow classifier 1, and the raw material to be classified 1 remains on the surface of the member in the airflow classifier 1 even during continuous operation.
5 hardly accumulate. In addition, since the member on which the composite plating film is formed has a necessary rigidity and the like, the posture and arrangement position of the surface thereof are largely displaced even by the air current or the collision of the particles of the material to be classified 15. Accordingly, the flow of the raw material particles 15 flying can be favorably controlled.

Further, the member on which the composite plating film is formed is widely installed in the airflow classification device 1 so that
It is possible to thoroughly prevent the material to be classified 15 from being fused and deposited. Therefore, even when the material to be classified 15 is a low melting point toner or the like, the particles of the material to be classified 15 are less likely to be fused to the surface of the member in the airflow classifier 1 where the particles of the material to be classified 15 collide with each other. Significantly reduces the number of operations to suspend and disassemble the equipment for removal, thereby improving the equipment operation rate and productivity, and at the same time, improving the classification accuracy and maintaining long-term hard classification accuracy. be able to.

[0072]

According to the present invention, the above-mentioned conventional problems can be solved. Further, according to the present invention, even when the particles of the material to be classified are low melting point toner or the like, the particles of the material to be classified are fused on the surface of the member in the airflow classifier where the particles of the material to be classified collide. As a result, the air flow classifier is stopped for removing the fused material, and the decomposition is greatly eliminated. An airflow classifier capable of maintaining classification accuracy for a long period of time, and by using the airflow classifier, easily, easily, and efficiently produce a toner for developing an electrostatic image having a constant particle size distribution. Method that can be performed.
The composite plating film in the present invention has both the unique properties of the non-metallic fluorine compound and the unique properties of the matrix metal. That is, it has a high degree of lubricity, abrasion resistance, anti-contamination, and anti-stick properties derived from fluorine compounds, and has particularly excellent durability, heat resistance, chemical resistance, oil repellency, water repellency, and the like. Furthermore, it has high hardness, high strength, high thermal conductivity, high electrical conductivity and the like derived from the matrix metal, and exhibits excellent adhesion to a member as a base material. For this reason, the airflow classifier of the present invention has excellent various performances.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view for explaining an embodiment of an airflow classifier of the present invention.

FIG. 2 is an enlarged schematic cross-sectional explanatory view of a classification edge in the airflow classifier shown in FIG.

FIG. 3 is a schematic sectional view for explaining an example of a conventional airflow classifier.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Airflow classifier 2 Classification edge 2a Composite plating film 3 Classification edge 3a Composite plating film 4 Coanda block 4a Composite plating film 5 Back block 5a Composite plating film 7 Classification exhaust channel 8 Classification exhaust channel 9 Classification exhaust channel DESCRIPTION OF SYMBOLS 11 Inlet flow path 12 Inlet flow path 14 Raw material separation chamber 15 Classified raw material 16 Raw material supply nozzle 18 Hopper 19 Compressed gas 21 Pipe 21 a Composite plating film 22 Pipe 22 a Composite plating film 23 Pipe 23 a Composite plating film 30 Classification edge mounting Base 30a Composite plating film 31 Classification edge mounting base 31a Composite plating film

Claims (15)

[Claims] 1. An airflow classifier for dispersing and classifying particles using an airflow, wherein a composite plating film containing fine particles dispersedly provided is provided on the surface of a member in the airflow classifier where particles of the raw material to be classified collide. An airflow classifier characterized by the following. 2. A raw material separation chamber having a plurality of classification exhaust passages branched by a classification edge at an outlet side and an inlet passage opened at an inlet side, and a classification exhaust flow from the inlet passage. An airflow generating means for generating an airflow flowing toward the path, and a raw material supply nozzle for pressure-feeding and injecting the raw material to be classified into the raw material selection chamber by using a compressed gas. The airflow classifier according to claim 1, wherein the particles of the raw material to be classified that have been fed and injected are classified into respective classification exhaust passages by a scattered and descending action in a curved line shape corresponding to the particle diameter due to the Coanda effect. 3. The air classifier according to claim 1, wherein the volume average particle diameter of the fine particles is 2 μm or less. 4. An inner wall of the raw material separation chamber, an outer wall of the classification edge, and an exhaust air for the classification, in which the surface of a member in the airflow classifier collides with particles of the raw material to be classified, which are fed and injected from the raw material supply nozzle. The airflow classifier according to claim 2 or 3, which is an inner wall of the flow path. 5. The airflow classifier according to claim 1, wherein the contact angle of the composite plating film with water in a droplet method is 100 ° or more. 6. The airflow classifier according to claim 1, wherein the fine particles are fine particles of a fluorine compound. 7. The airflow classifier according to claim 1, wherein the fine particles are fine particles of two or more kinds of fluorine compounds. 8. The air classifier according to claim 6, wherein the fluorine compound is selected from fluororesin, fluorinated graphite {(CF) n} and fluorinated pitch. 9. The air classifier according to claim 8, wherein the fluororesin is selected from polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer and tetrafluoroethylene-perfluoroalkylvinyl ether copolymer. 10. The air classifier according to claim 1, wherein the composite plating film is heat-treated at 150 to 300 ° C. 11. A process for preparing a kneaded product by melt-kneading a binder resin and a colorant, a process for preparing a pulverized product by pulverizing the kneaded product, and A method for producing a toner for developing an electrostatic image, comprising a step of classifying using the airflow classifier according to any one of the above. 12. The method for producing a toner for developing an electrostatic image according to claim 11, wherein the binder resin is polyester. 13. The method for producing a toner for developing an electrostatic image according to claim 11, wherein the glass transition point of the toner for developing an electrostatic image is 50 to 65 ° C. 14. The softening point of the toner for developing an electrostatic image is 12
The method for producing a toner for developing an electrostatic image according to claim 11, wherein the temperature is 0 ° C. or lower. 15. An electrostatic image developing toner having an average particle size of 9
The method for producing a toner for developing electrostatic images according to any one of claims 11 to 14, wherein the particle diameter is not more than μm.