JP2006159075A - Pneumatic impact pulverizer, method for manufacturing electrostatic charge image developing toner and electrostatic charge image developing toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic impact pulverizer which uses jet air flow and provides a toner having a small grain size and a high sharpness of a grain size distribution, and a method for manufacturing an electrostatic charge image developing toner of the small grain size and the high sharpness of the grain size distribution with which an image of high image quality can be obtained by using the pulvereizer. <P>SOLUTION: The pneumatic impact pulverizer is equipped with a jet nozzle for jetting a jet air flow to a pulverization chamber, a jet air flow path for supplying a material to be pulverized to the jet air flow, and an impact plate provided in a position facing the jet nozzle, wherein the edge of the impact plate is chamfered. In addition, the toner particles obtained by subjecting a raw material containing at least a resin and a colorant to melt kneading and cooling are pulverized by the pulverizer, thereby forming the fine grain toner. <P>COPYRIGHT: (C)2006,JPO&amp;NCIPI

Description

  The present invention relates to a collision airflow type pulverization apparatus used for manufacturing an electrostatic charge image developing toner, and more particularly, to a collision airflow type pulverization apparatus using a jet airflow from which fine toner particles are obtained. The present invention also relates to a method for producing an electrostatic image developing toner capable of obtaining a high-quality image by the apparatus, and an electrostatic image developing toner produced by the production method.

  Conventionally, a collision airflow type pulverizer is known as a device for atomizing coarse particles of toner. As shown in FIG. 3, a general apparatus of this collision airflow type pulverization apparatus is configured such that coarse particle toner a which is a pulverized object is introduced from a pulverized object supply port 3 at the upper part of the pulverizing apparatus 1 and is injected into the ejection nozzle 2. Supplied. By sending the jet jet b to the jet nozzle 2, the coarse toner particles ride on the high-pressure jet jet and fly at an ultra-high speed and collide with the collision plate 5 provided in the opposite direction to become fine particles. The fine particle toner c that has been finely divided by the collision further collides with the wall surface of the crushing chamber 4 to become finer particles, passes between the collision plate support 6 and the crushing chamber 4, and is sent to the pulverized material discharge port 7.

  In recent years, the electrostatic image developing toner produced as described above has been increasing in market demands such as improved dot reproducibility for obtaining high-quality images and improved low-temperature fixability for the purpose of energy saving. However, there is a limit to reducing the particle size in the above-mentioned general apparatus.

In the conventionally proposed apparatus, for example, a secondary collision plate is detachably provided in the crushing chamber according to the speed of the jet jet (see Patent Document 1), or a crushing collision member is directly installed in the crushing chamber. A conical surface surrounding a conical surface having a conical concave surface (see Patent Document 2), a projecting central portion from which a colliding surface of a colliding member projects, and a pulverized central portion around the projecting central portion An outer peripheral collision surface for secondary pulverization of the finely pulverized primary pulverized material by collision, and further pulverizing the secondary pulverized material by the side wall of the pulverization chamber (see Patent Document 3), and collision plate The material collision surface is a flat plane perpendicular to the axis of the nozzle, and a conical protrusion is provided coaxially with the nozzle on the material collision surface (see Patent Document 4). However, any of the above conventional techniques is a method that is biased toward either ultra-small particle size or sharp particle size distribution. To achieve both ultra-small particle size and sharpness, the toner yield decreases and the cost decreases. There was a problem that would be up.
Japanese Patent No. 3133100 Japanese Patent No. 3090558 Japanese Patent Laid-Open No. 8-103685 No. 7-25227

  The present invention has been made in view of the above problems, and in a collision airflow type pulverization apparatus using a jet airflow, a collision with which a toner having a small particle size and a high sharpness of particle size distribution can be obtained without reducing productivity. Providing an airflow-type pulverizing apparatus, a method for producing a toner for developing an electrostatic image with a small particle size and a high sharpness of particle size distribution, which can obtain a high-quality image using the apparatus, and an electrostatic charge produced by the production method An object is to provide a toner for image development.

  The object of the present invention is achieved by the following means. That is, according to the present invention, firstly, a jet nozzle for jetting a jet jet into the grinding chamber, a jet jet channel for supplying an object to be ground to the jet jet, and a collision plate provided at a position facing the jet nozzle The collision airflow type pulverization apparatus is provided with a chamfering process performed on the edge portion of the collision plate.

  Secondly, in the collision airflow type pulverization apparatus described in the first aspect, a collision airflow type pulverization apparatus is provided in which a chamfer width (C in the drawing) of the collision plate is 2 to 10 mm.

  Thirdly, in the collision airflow type pulverization apparatus described in the second aspect, there is provided a collision airflow type pulverization apparatus characterized in that a chamfer angle (θ in the figure) of the chamfer width is 30 ° to 60 °.

  Fourth, the collision airflow type crushing apparatus according to the first aspect is provided, wherein the chamfered surface is a curved surface.

  Fifth, the collision airflow crusher according to any one of the first to fourth, wherein the material of the collision plate is a hardness of 1400 or more (Vickers hardness: 1000 g load). Is provided.

  Sixth, the collision airflow type pulverization apparatus according to any one of the first to fifth aspects is provided, wherein the collision plate has a surface roughness of Rmax 1.6 μm or less. .

  Seventh, by using the impinging air flow type pulverizing apparatus according to any one of the first to sixth aspects, coarse particle toner obtained by melt kneading and cooling at least a raw material containing a resin and a colorant and then coarsely pulverizing the raw material is used. And a method for producing a toner for developing an electrostatic charge image.

  Eighth, there is provided an electrostatic image developing toner produced by the method for producing an electrostatic image developing toner described in the seventh aspect.

  According to the collision airflow type pulverizing apparatus of claim 1, since the edge portion of the collision plate is chamfered, the turbulence generated at the edge portion of the collision plate can be reduced. While reducing the impact of the light fine powder particles made on the wall surface of the grinding chamber, the heavy particles can be made to collide with the wall surface of the grinding chamber, so that over-pulverization of the fine powder particles can be suppressed and the coarse powder particles can be ground again. A toner having a small particle size and a sharp particle size distribution can be obtained.

  According to the collision airflow type pulverization apparatus of claim 2, since the chamfer width (C in the figure) of the collision plate is 2 to 10 mm, the above-described reduction of the turbulence is obtained, and the effect of suppressing the excessive pulverization of fine particles and The selective pulverization effect of coarse powder particles (only coarse powder particles collide with the pulverization chamber side surface and pulverized again) can be enhanced.

  According to the collision airflow type pulverizing apparatus of claim 3, since the chamfering angle (θ in the figure) is 30 ° to 60 ° in the chamfering width, the hardness of the resin component tends to be low and excessive crushing tends to occur. However, the effect of suppressing excessive pulverization of fine powder particles can be obtained.

  According to the collision airflow type pulverizer of claim 4, since the chamfered surface is a curved surface, the above-described excessive pulverization suppressing effect of fine particles and the selective pulverizing effect of coarse particles can be reliably obtained in this case as well. .

  According to the impingement airflow type pulverizer of claim 5, since the material of the impingement plate has a hardness of 1400 or more (Vickers hardness: 1000 g load), the wear resistance is remarkably improved, and the ultra-small particle size and sharpness are improved. Production of a characteristic particle size distribution can be continued for a long time.

  According to the collision airflow type pulverization apparatus of the sixth aspect, since the surface roughness of the collision plate is Rmax 1.6 μm or less, mirror finishing can be obtained and toner adhesion during continuous operation can be prevented. Moreover, the cleaning work time spent for adhesion removal is shortened, and the maintainability is improved.

  According to the method for producing a toner for developing an electrostatic charge image according to claim 7, the coarse particle toner obtained by coarse pulverization by the pulverization method is atomized using the collision airflow type pulverizer, so that the small particle size and sharpness are reduced. Therefore, a toner for developing an electrostatic image capable of forming a high-quality image can be obtained.

  According to the electrostatic image developing toner of the eighth aspect, since the toner is obtained by the above-described production method, a high-quality image with excellent dot reproducibility can be obtained.

Hereinafter, the present invention will be described in detail with reference to the drawings.
FIG. 1 shows a block diagram of a collision airflow type pulverizer according to the present invention. As shown in the figure, there are provided a jet nozzle 2 for jetting a jet jet b to the grinding chamber 4, a jet jet passage for supplying the jetted product a to the jet jet, and a collision plate 5 provided at a position facing the jet nozzle. In the collision airflow crusher, the edge portion of the collision plate 5 is chamfered. By chamfering in this way, turbulence generated at the collision plate edge can be reduced. As a result, the light fine powder particles are not affected by the turbulent airflow, the collision with the pulverization chamber wall surface is also reduced, and the particles pass between the collision plate support 6 and the pulverization chamber 4 and are sent to the discharge port 7. Further, excessive pulverization of fine powder particles, which is a cause of broad particle size distribution, can be suppressed. On the other hand, since the heavy coarse particles are collided and pulverized again on the wall surface of the crushing chamber and pass between the collision plate support 6 and the crushing chamber 4 and are sent to the discharge port 7, Collision (only coarse particles collide with the grinding chamber wall surface) can be obtained. By these two actions, a toner having a small particle size and a sharp particle size distribution can be obtained.

  FIG. 2 is an explanatory diagram of the chamfering process, and shows that the edge portion of the collision plate is chamfered with a width C and an angle θ. If the chamfer width C is narrower than 2 mm, the effect of reducing turbulence at the edge portion is not observed, and the fine powder content does not change. On the other hand, when the chamfer width C is larger than 10 mm, the turbulence at the edge portion is reduced and the fine powder content is reduced, but the average particle size is also increased. Therefore, if the chamfering width C is 2 to 10 mm, the effect of suppressing excessive pulverization of fine particles and the effect of selective pulverization of coarse particles can be enhanced.

  By setting the chamfering width C of the collision plate edge portion to 2 to 10 mm as described above, the effect of suppressing excessive pulverization of fine particles and the effect of selective pulverization of coarse particles can be enhanced. Even if it is low and tends to be excessively pulverized, excessive crushing can be prevented if the chamfering angle θ is in the range of 30 ° to 60 ° with this chamfering width.

  In addition, the chamfered surface is a curved surface, that is, when chamfering is performed in a round shape, if the chamfering is in the range of radius 2 mm to radius 10 mm, it has an effect of suppressing excessive pulverization of fine particles and an effect of selective pulverization of coarse particles. Was confirmed.

  Furthermore, if the material of the collision plate member is a hardness of 1400 or more (Vickers hardness: 1000 g load), the wear resistance is remarkably improved, and the production of a particle size distribution with a very small particle size and sharpness is prolonged. Can be maintained for hours.

  Further, by applying a mirror finish to the collision plate member by buffing or the like so that the surface roughness Rmax is 1.6 μm or less, it is possible to prevent toner adhesion during continuous operation. As a result, the cleaning work time spent for removing the adhesion is shortened, the maintainability is improved, and the production of a particle size distribution having a small particle size and sharpness can be continuously performed for a long time.

  As described above, as shown in FIG. 1, the pulverizing apparatus of the present invention supplies the coarse particle toner a obtained by the pulverization method to the ejection nozzle 2 from the pulverized object supply port at the upper part of the apparatus. When the jet jet b is fed into the coarse particle toner a, the coarse particle toner a rides on the high-pressure jet jet and collides with the collision plate 5 provided in the opposite direction while flying at an ultra-high speed to be atomized. The large particles in the fine particle toner c atomized by the collision further collide with the wall surface of the crushing chamber 4 and are pulverized to be atomized, and the small particles pass between the collision plate support 6 and the crushing chamber 4. It is sent to the pulverized product outlet 7 without being excessively pulverized.

The coarse toner particles pulverized by the pulverizing apparatus of the present invention may be those coarsely pulverized by a pulverization method, and generally used raw materials as shown below can be used.
A conventionally well-known thing can be widely used as binder resin for toners. For example, vinyl resin, polyester resin or polyol resin.

  As the vinyl resin, styrene such as polystyrene, poly-P-chlorostyrene, and polyvinyltoluene, and homopolymers thereof: styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer Polymer, styrene-vinyl naphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methacrylic acid Methyl copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer , Styrene-vinyl ethyl ether Copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer, styrene-maleic acid copolymer, styrene-maleic acid ester copolymer Styrene copolymers such as polymers: polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate and the like.

The polyester resin is composed of a dihydric alcohol as shown in the following group A and a dibasic acid salt as shown in the group B, and further a trivalent or higher alcohol as shown in the group C or Carboxylic acid may be added as a third component.
Group A: ethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4 butanediol, neopentyl glycol, 1,4 butenediol, 1,4-bis (hydroxymethyl) cyclohexane Bisphenol A, hydrogenated bisphenol A, polyoxyethylenated bisphenol A, polyoxypropylene (2,2) -2,2′-bis (4-hydroxyphenyl) propane, polyoxypropylene (3,3) -2, 2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2,0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (2,0) -2,2′-bis (4 -Hydroxyphenyl) propane and the like.

  Group B: maleic acid, fumaric acid, mesaconic acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, succinic acid, adipic acid, sebacic acid, malonic acid, linolenic acid, or These acid anhydrides or esters of lower alcohols.

  Group C: Trivalent or higher alcohols such as glycerin, trimethylolpropane and pentaerythritol, and higher trivalent carboxylic acids such as trimellitic acid and pyromellitic acid.

  As the polyol resin, an alkylene oxide adduct of an epoxy resin and a dihydric phenol, or a compound having one active hydrogen in the molecule that reacts with the glycidyl ether and the epoxy group, and an active hydrogen that reacts with the epoxy resin in the molecule. There are those obtained by reacting two or more compounds.

In addition, the following resins can be mixed and used as necessary.
Epoxy resin, polyamide resin, urethane resin, phenol resin, butyral resin, rosin, modified rosin, terpene resin, etc.
The epoxy resin is typically a polycondensate of bisphenol such as bisphenol A or bisphenol F and epichlorohydrin.

The following are used as the pigment.
Examples of black pigments include azine dyes such as carbon black, oil furnace black, channel black, lamp black, acetylene black, and aniline black, metal salt azo dyes, metal oxides, and composite metal oxides.

  Examples of yellow pigments include cadmium yellow, mineral fast yellow, nickel titanium yellow, navel yellow, naphthol yellow S, hansa yellow G, hansa yellow 10G, benzidine yellow GR, quinoline yellow lake, permanent yellow NCG, and tartrazine lake. .

  Examples of the orange pigment include molybdenum orange, permanent orange GTR, pyrazolone orange, Vulcan orange, indanthrene brilliant orange RK, benzidine orange G, and indanthrene brilliant orange GK.

  Examples of red pigments include Bengala, Cadmium Red, Permanent Red 4R, Resol Red, Pyrazolone Red, Watching Red Calcium Salt, Lake Red D, Brilliant Carmine 6B, Eosin Lake, Rhodamine Lake B, Alizarin Lake, Brilliant Carmine 3B.

Examples of purple pigments include fast violet B and methyl violet lake. Examples of blue pigments include cobalt blue, alkali blue, Victoria blue lake, phthalocyanine blue, metal-free phthalocyanine blue, phthalocyanine blue partially chlorinated, first sky blue, and indanthrene blue BC.
Examples of green pigments include chrome green, chromium oxide, pigment green B, and malachite green lake.
These can use 1 type (s) or 2 or more types. The amount used is generally 0.1 to 50 parts by weight per 100 parts by weight of the binder resin.

  Mold release agents include low molecular weight polyethylene and polypropylene, synthetic waxes such as copolymers thereof, plant waxes such as candelilla wax, carnauba wax, rice wax, wood wax, jojoba wax, beeswax, lanolin, whale Animal waxes such as wax, mineral waxes such as montan wax and ozokerite, oiled wax such as hydrogenated castor oil, hydroxystearic acid, fatty acid amide, phenol fatty acid ester and the like. Of these, carnauba wax and polypropylene are preferred.

The following are used as the charge control agent.
For controlling the toner to be positively charged, nigrosine, a quaternary ammonium salt, an imidazole metal complex and salts can be used alone or in combination of two or more. Further, salicylic acid metal complexes, salts, organic boron salts, calixarene compounds, and the like are used for controlling the toner to be negatively charged.

  The steps are described in order. First, raw materials are weighed and mixed. As a mixing device, a double cone mixer, a V-type mixer, a drum-type mixer, a super mixer, a Henschel mixer, a Nauter mixer, or the like can be used.

  Next, kneading is performed in a kneading step. At that time, it can be kneaded using a batch type extruder (for example, a pressure kneader, a Banbury mixer, a two-roller, etc.) or a continuous type extruder. Machines are the mainstream, and for example, KTK type twin screw extruder manufactured by Kobe Steel, TEM type twin screw extruder manufactured by Toshiba Machine, etc. are used.

  The kneaded product is rolled by a rolling roll or the like, and cooled by air cooling, water cooling or the like in a cooling step. Next, it is roughly crushed by a crusher, a hammer mill, a feather mill or the like.

  In the pulverizing apparatus of the present invention, coarse toner particles coarsely pulverized as described above are used, finely pulverized, and gradually pulverized to a predetermined toner particle size.

  After pulverization, the toner is classified with an inertia classification elbow jet, a centrifugal classification microplex, a DS separator, or the like to obtain a classified toner. Furthermore, when externally added to the toner, predetermined amounts of various known additives are blended into the classified toner, and after stirring and mixing with a high-speed stirrer that gives shearing force such as a super mixer and a Henschel mixer, After passing through a sieving step for removing dust and the like mixed in the manufacturing process, the toner is filled into a container as the final toner.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

Using the pulverizer shown in FIG. 1, coarse particles shown below are introduced as an object to be crushed, and the radius R (mm) of the collision plate, the chamfering width C (mm) of the edge portion, and the chamfering angle θ (°) of the edge portion. ), The thickness (mm) of the collision plate, the surface roughness Rmax (μm) of the collision plate member, and the material of the collision plate member. A pulverizer having a maximum ejection flow rate of 20 m ³ / min was used.
(Coarse particles)
Styrene / acrylic resin 20 parts by weight Polyester resin 80 parts by weight Carbon black 10 parts by weight Carnauba wax 4.95 parts by weight Quaternary ammonium salt 2 parts by weight After mixing the above raw materials with a super mixer, a TEM type twin screw kneader (Toshiba Machine) Co., Ltd.), and after cooling, coarsely pulverized to obtain coarse particle toner.

The obtained coarse particle toner was pulverized by a pulverizer having a collision plate and a collision plate member shown in Table 1, and the following evaluation was performed.
(Evaluation items and measurement method)
(1) Volume average particle size (2) Fine powder content (4 μm or less, volume%)
The weight average particle size and particle size distribution sharpness were measured with a Coulter Counter TAII (Coulter).
(3) Wear of collision member by continuous operation The coarse particle toner was pulverized by the above pulverizer for 100 hours of continuous operation, and the wear state of the collision member was visually evaluated.
(4) Amount of toner adhering to the collision member by continuous operation After the weight of the collision plate 5 is measured before the operation of the apparatus, it is attached to the collision plate support. The coarse particle toner was pulverized with the above pulverizer by continuous operation for 100 hours, and only the collision plate 5 was removed from the collision plate support to measure the weight, and the increase in weight before and after the operation was examined.
The above evaluation results are shown in Table 2.

  From Table 2, it can be seen that (1) the examples have a volume average particle size of 26.6 μm to 33.5 μm, and the grindability is clearly improved as compared with the comparative examples of 34.3 μm and 45.2 μm. Further, the conical shape of Comparative Example 2 has a worse grindability than the flat shape of Comparative Example 1. (2) There is no clear difference in the fine powder content. (3) Impact member wear due to continuous operation occurred in steel, but not in ceramic. (4) It can be seen that the amount of toner adhering to continuous operation is smaller in the example than in the comparative example, and in particular when the surface roughness of the collision member is small.

It is sectional drawing which shows an example of the grinding | pulverization apparatus of this invention. It is explanatory drawing of the chamfering process of a collision board edge part, (a) is a front view, (b) is a side view. It is sectional drawing of the conventional collision airflow type crusher.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Crushing device 2 Jet nozzle 3 Ground supply port 4 Grinding chamber 5 Collision plate 6 Collision plate support 7 Ground material discharge port a Ground material b Jet jet c Ground material

Claims (8)

  In the collision airflow type pulverization apparatus comprising: an ejection nozzle that ejects a jet jet into the pulverization chamber; a jet jet passage that supplies an object to be crushed to the jet jet; and a collision plate that is provided at a position facing the ejection nozzle. A collision airflow type crusher characterized by chamfering the edge portion of the collision plate.   2. The collision airflow type crusher according to claim 1, wherein the chamfer width of the collision plate is 2 to 10 mm.   The impingement airflow type crusher according to claim 2, wherein a chamfering angle θ of the chamfer width is 30 ° to 60 °.   2. The collision airflow type crusher according to claim 1, wherein the chamfered surface is a curved surface.   5. The collision airflow type crusher according to any one of claims 1 to 4, wherein the material of the collision plate is a hardness of 1400 or more (Vickers hardness: 1000 g load).   6. The collision airflow type pulverization apparatus according to any one of claims 1 to 5, wherein the collision plate has a surface roughness of Rmax 1.6 [mu] m or less.   7. The coarse particle toner obtained by coarsely pulverizing a raw material containing at least a resin and a colorant after being melt-kneaded and cooled, and then atomized using the impinging airflow pulverizer according to any one of claims 1 to 6. A method for producing a toner for developing an electrostatic charge image.   An electrostatic image developing toner produced by the method for producing an electrostatic image developing toner according to claim 7.

Images