KR20000016507A - Colored magnetic toner and process for preparing the same - Google Patents

Abstract

PURPOSE: Provided are a powdery material for a vividly colored magnetic toner including a white color used in a color copying machine, and a dry colored magnetic toner prepared therefrom. CONSTITUTION: The toner comprises a powder comprising a light-interference multilayer coating (2, 3) formed on a magnetic particle (1) and at least one organic polymer coating layer (4) or colored layer provided on the surface of the powder. The process for preparing the same comprises applying at least one organic polymer coating layer (4) on the surface of a powder having a light-interference multilayer coating.

Description

Color magnetic toner and its manufacturing method

Background Art [0002] At present, there are a two-component developing method in which an image forming method in copying, printing or the like by an electrophotographic method uses a carrier having magnetic properties and a toner serving as a color material and a one-component developing method in which the toner itself has magnetic properties.

Since the one-component developing method does not use a carrier, there are many advantages such as the developing device is simple (the size of the developing device is about one-third of the two-component developing method), and the developer can be easily managed. . However, in the case where a color image is to be formed, the magnetic toner becomes black, and a vivid color cannot be obtained.

The reason is that in order to obtain a vivid color image by the one-component developing method, it is necessary to vividly color the magnetic toner itself, and since the magnetic particles serving as the base material thereof are generally black, a colored film is formed directly on the surface thereof. Even if it is black overall.

Therefore, the two-component developing method is currently employed for color image formation. Since four colors, three primary colors and black, are required for color copying, the developing apparatus naturally grows.

In addition, management of a developer, processing of a carrier generated after image formation, and the like are also problematic.

Therefore, if a vivid color is obtained by the one-component developing method, since the copying apparatus is simplified and downsized, and the problem of managing the developer and processing of the carrier is also solved, the one-component developing suitable for color image formation as described above is preferable. Magnetic toner for the method has not yet been provided.

On the other hand, the present inventors first disperse the particles of the base material in the metal alkoxide solution and hydrolyze the metal alkoxide, thereby producing a metal oxide film having a uniform thickness of 0.01 to 20 μm on the particle surface of the base material ( Patent Publication No. Hei 6-228604), a functional powder formed by alternating a thin film of metal oxide and a thin film of metal on the surface (patent publication No. 7-90310), and coating multiple layers with a metal oxide film Has been proposed (WO96 / 28169) to produce a powder having a denser and more stable multiple layer metal oxide film.

The above-mentioned metal oxide film or powder formed of a plurality of metal films can impart a special function by adjusting the film thickness of each layer. For example, a coating film having a different refractive index is applied to the particle surface of the base material. By forming the thickness corresponding to one quarter of the wavelength, a powder that reflects all incident light is obtained. Applying this to making the magnetic material particles of the base material, it is possible to produce magnetic powder for magnetic toner that reflects all of the light and shines in white, and forms a colored layer on the surface of the magnetic powder and forms a resin layer thereon. When formed, this suggests the possibility of producing a colored magnetic toner colored in vivid colors.

Accordingly, an object of the present invention is to further develop the above-described technology proposed by the present inventors, and to provide a color magnetic toner in which vivid colors are obtained even in a one-component system.

The present invention relates to a composite powder which is a raw material such as color magnetic toner, color magnetic ink, and the like, and a manufacturing method thereof.

FIG. 1 is a schematic cross-sectional view showing the form of one embodiment of the color magnetic toner according to the present invention described above, and as shown, on the magnetic body particles 1, which are particles of a base material, An optically coherent multilayer film formed by laminating other metal compound films 3 is formed, and the outermost layer surface is covered with the organic polymer film 4. In addition, either the metal compound film 2 or the other metal compound film 3 may be a metal film.

Example

Hereinafter, an Example and a comparative example will demonstrate this invention more clearly. However, this invention is not limited by the following example.

Example 1

Method of preparing oxide coated powder

1st layer: silica coating

10 g of carbonyl iron powder (average particle diameter: 1.8 mu m) manufactured by BASF was dispersed in 100 ml of ethanol, and the vessel was heated by an oil bath to maintain the liquid temperature at 55 deg. 6 g of silicon ethoxide, 6 g of ammonia water (29%), and 8 g of water were added thereto, followed by reaction for 2 hours with stirring. After the reaction, the mixture was diluted and washed with ethanol, filtered, and dried at 110 ° C. for 3 hours in a vacuum dryer. After drying, heat treatment was performed at 650 ° C. for 30 minutes using a rotary tube furnace to obtain a silica coating powder (A).

The film thickness of the obtained silica coating powder (A) was 75 nm, and the dispersion state was very favorable.

2nd layer: titania coating

After the heat treatment, 10 g of the obtained silica coated powder (A) was further added to 200 ml of ethanol and dispersed, and the vessel was heated by an oil bath to maintain the temperature of the liquid at 55 ° C. After adding 5 g of titanium ethoxide to the mixture and stirring it, a mixed solution of 30 ml of ethanol and 8.0 g of water was added dropwise over 60 minutes, reacted for 2 hours, dried under vacuum and heat treated to obtain a silica / titania-coated powder ( B) was obtained.

The obtained silica titania coating powder (B) had good dispersibility and was a single particle, respectively. In addition, the thickness of the titania film of the silica titania coating powder (B) was 50 nm.

In addition, the peak wavelength of the spectral reflection curve of this powder was 445 nm, the reflectance at the peak wavelength was 40%, and was bright blue.

Polystyrene composite powder

500 g of styrene monomer was added to 600 g of distilled water, and the mixture was heated to 70 ° C and emulsified by adding sodium lauryl sulfate while stirring. Thereafter, 25 g of the silica-titania-coated powder (B) lipophilic with methacrylic acid was added, and the mixture was stirred at a high speed and sufficiently mixed.

10% aqueous ammonium persulfate solution was added thereto to initiate the polymerization reaction, followed by stirring for 4 hours. After the completion of the reaction, the mixture was diluted with 2 L of distilled water, the supernatant was discarded by gradient washing, and the precipitates were collected and dried on filter paper to obtain a blue polystyrene coated powder.

The obtained blue polystyrene coating powder was spherical in shape, and the magnetization in the magnetic field of 10 kOe was 120 emu / g.

Example 2

1st layer: silica coating

10 g of carbonyl iron powder (average particle diameter: 1.8 mu m) manufactured by BASF was dispersed in 100 ml of ethanol, and the vessel was heated by an oil bath to maintain a liquid temperature of 55 deg. 6 g of silicon ethoxide, 6 g of ammonia water (29%), and 8 g of water were added thereto, and reacted for 2 hours with stirring. After the reaction, the mixture was diluted and washed with ethanol, filtered, and dried at 110 ° C. for 3 hours in a vacuum dryer. After drying, heat treatment was performed at 650 ° C. for 30 minutes using a rotary tube furnace to obtain a silica coating powder (B).

The film thickness of the obtained silica coating powder (B) was 70 nm, and the dispersion state was very favorable.

Second layer: titania coating

After heat treatment, 10 g of the obtained silica coated powder (B) was further added to 200 ml of ethanol and dispersed, and the vessel was heated by an oil bath to maintain the temperature of the liquid at 55 ° C. 4.7 g of titanium ethoxide was added thereto and stirred, and a mixed solution of 30 ml of ethanol and 8.0 g of water was added dropwise over 60 minutes, followed by reaction for 2 hours, vacuum drying, and heat treatment to coat silica and titania. Powder (C) was obtained.

The obtained silica titania coating powder (C) had good dispersibility and was a single particle, respectively. In addition, the thickness of the titania film of the silica titania coating powder (C) was 45 nm.

Moreover, the peak wavelength of the spectral reflection curve of this powder was 410 nm, the reflectance at the peak wavelength was 41%, and was clear blue purple.

3rd layer: silica coating

10 g of silica titania coating powder (C) was dispersed in 100 ml of ethanol, and the vessel was heated by an oil bath to maintain the temperature of the liquid at 55 ° C. 6 g of silicon ethoxide, 6 g of ammonia water (29%), and 8 g of water were added thereto, followed by reaction for 2 hours with stirring. After the reaction, the mixture was washed with ethanol, filtered, and then dried at 110 ° C. for 3 hours in a vacuum dryer. After drying, heat treatment was performed at 650 ° C. for 30 minutes using a rotary tube furnace to obtain silica-titania-silica-coated powder (D).

The film thickness of the obtained silica titania-silica coating powder (D) was 75 nm, and the dispersion state was very favorable.

4th layer: titania coating

After heat treatment, 10 g of the obtained silica-titania-silica-coated powder (D) was further added to 200 ml of ethanol and dispersed, and the vessel was heated by an oil bath to maintain the liquid temperature at 55 ° C. 5.5 g of titanium ethoxide was added thereto and stirred. A mixed solution of 30 ml of ethanol and 8.0 g of water was added dropwise thereto over 60 minutes, followed by reaction for 2 hours, followed by vacuum drying and heat treatment to obtain silica, titania, silica, titania coated powder (E).

The obtained silica titania silica titania coating powder (E) had good dispersibility and was a single particle, respectively. In addition, the thickness of the titania film newly formed in the silica titania silica titania coating powder (E) was 53 nm.

Polystyrene composite powder

90 g of styrene monomer and 10 g of butylene acrylate were added to 600 g of distilled water, and sodium lauryl sulfate was added thereto while heating to 70 ° C and stirring.

Thereafter, 50 g of silica titania, silica titania coating powder (E) was added, and the mixture was stirred at a high speed and sufficiently mixed.

To this was added 10% aqueous ammonium persulfate solution to initiate the polymerization reaction, and stirred for 4 hours to react. After the completion of the reaction, the mixture was diluted with 2 L of distilled water, the supernatant was discarded by decanting and the precipitate was dried on filter paper to obtain a blue polystyrene coating powder.

The peak wavelength of the spectral reflection curve of the obtained polystyrene coating powder was 445 nm, the reflectance at the peak wavelength was 55%, and was bright blue. In addition, the magnetization of the powder at a magnetic field of 10 kOe was 78 emu / g.

Comparative Example 1

When magnetic substance and pigment are simply mixed

25 g: 25 g weight ratio of this and carbonyl iron powder (average particle diameter 1.8 mu m) manufactured by BASF, using Torco blue (blue pigment) reflectance (average particle diameter 0.2 mu m, reflection peak 455 mu m, reflectance 55%). The mixture was mixed with and sufficiently homogenized.

90 g of styrene monomer and 10 g of butylene acrylate were added to 600 g of distilled water, and the mixture was heated and stirred to 70 ° C. The powder was added to an emulsified solution of sodium lauryl sulfate, stirred at high speed, and sufficiently mixed.

To this, 10% aqueous ammonium persulfate solution was added to initiate a polymerization reaction, followed by stirring for 4 hours.

After completion of the reaction, the mixture was diluted with 2 L of distilled water, the supernatant was discarded by decanted washing, and the precipitate was dried on filter paper, so that both the pigment and the iron powder were covered with polystyrene to obtain an integral spherical powder.

The polystyrene coating powder (A) was dark blue, the reflection peak was 455 nm, and the reflectance was reduced to 22%. In addition, the magnetization of the powder at a magnetic field of 10 kOe was 75 emu / g.

As can be seen from the comparison between Example 2 and Comparative Example 1, the color in the case of simply mixing the pigment, the magnetic particles, and the binder resin was not good, and even in the case of color magnetic toner having the same magnetization, It was confirmed that it was necessary to color the magnetic body particles as in Example 2.

Example 3

10 g of oil blue, which is an organic dye, was dissolved in 20 g of benzene, and 90 g of styrene monomer and 10 g of butylene acrylate were mixed to prepare a colored resin.

The colored resin raw material was added to 600 g of distilled water, sodium lauryl sulfate was added, and the mixture was stirred while being emulsified to 70 ° C.

Thereafter, 50 g of the silica-titania-coated powder (E) prepared in the same manner as in Example 2 was added thereto, and the mixture was stirred at a high speed and sufficiently mixed.

A 10% ammonium persulfate aqueous solution was added to this, and polymerization reaction was performed for 5 minutes. After the completion of the reaction, the mixture was diluted with 2 L of distilled water and washed twice with decanter, and then the precipitate was filtered and washed to obtain a blue polystyrene coating powder (B).

The peak wavelength of the spectral reflection curve of the obtained polystyrene coating powder (B) was 455 nm, and the reflectance at the peak wavelength was 52%. Moreover, the magnetization in the magnetic field of 10 kOe of this polystyrene coating powder (B) was 75 emu / g.

In addition, the polystyrene-coated powders (A, B) obtained in Example 3 and Comparative Example 1 were uniformly and uniformly applied to 80% of the area of A4 copy paper by 1.7 g each using a coater. The polystyrene coating powder (B) of Example 3 became bright blue. However, in the polystyrene coating powder (A) obtained in the comparative example 1, it became dark gray.

According to the present invention the above object,

(1) a color magnetic toner, wherein an optically coherent multilayer film is formed on particles of a base material made of a magnetic material, and an organic polymer film is formed on the optically coherent multilayer film,

(2) the color magnetic toner according to (1), wherein the optically coherent multilayer film reflects light in the visible region;

(3) The color magnetic toner according to the above (1) or (2), wherein the organic polymer film contains a colorant, and

(4) The optically coherent multilayer film is achieved by the color magnetic toner according to any one of the above (1) to (3), characterized in that the metal compound film and / or the metal film are laminated in multiple layers.

In addition, the above object according to the present invention,

(5) A method of producing a color magnetic toner, which is characterized in that an organic polymer film is formed by a polymerization method after forming a multilayer film made of a metal compound and / or a metal on magnetic body particles.

According to the above constitution, a multilayer optical coherent coating film made of a metal compound film and / or a metal film is formed on the magnetic particles, and as a powder exhibiting a white color or a desired color by such a film structure, the organic binder composition is formed thereon. By forming the polymer film, it is possible to provide a color magnetic toner capable of forming a vivid color image even in one component system.

In addition, by incorporating a colorant into the organic polymer film, it is possible to give a more vivid color.

Hereinafter, the color magnetic toner according to the present invention will be described in detail based on the preferred embodiments.

As the magnetic particles used as the base material of the color magnetic toner of the present invention, magnetic particles used conventionally as the base material of the magnetic toner may be used. Typically, metal powders such as iron, cobalt and nickel, alloy powders thereof, or magnetic sintered powders such as iron nitride can be used.

However, since magnetic particle tends to be used finely in order to increase the resolution, it is preferable to use a magnetic substance having large magnetization. Preferably, a magnetic substance having a magnetization of 90 emu / g or more, preferably 150 emu / g or more when a magnetic field of 10 kOe is applied in the form of a powdery substance. Such a magnetic material having high magnetization becomes a raw material powder of color magnetic toner having a high magnetization of 10 to 90 emu / g (applying 10 kOe of magnetic field) as a whole even if a coloring resin, a charge control agent or a colorant is added as the color magnetic toner. .

In addition, the shape of the magnetic particle may be a polyhedron such as a sphere, a state similar to a sphere, an isotropic body such as a regular polyhedron, a rectangular parallelepiped, a spheroid, a rhombus, a plate-like body, a columnar body, or an indefinite shape.

In the present invention, in order to obtain a color magnetic toner showing a vivid color, it is necessary to color the magnetic particles with white or other vivid colors. For this reason, the multilayer film which has optical coherence is formed on magnetic body particle.

An optically coherent multilayer film is formed by stacking multiple layers of metals or metal compounds. In this case, the thickness of each film is adjusted or the order or combination of the layers is changed to reflect and absorb a specific wavelength region of incident light. It can be given. As a result, the magnetic particles can be colored in white or other vivid colors.

As a metal compound which forms the said multilayer film, a metal oxide, a metal sulfide, a metal serenide, a metal telluride, a metal fluoride, etc. are mentioned. More specifically, zinc oxide, aluminum oxide, cadmium oxide, titanium oxide, zirconium oxide, tantalum oxide, silicon oxide, antimony oxide, neodium oxide, lanthanum oxide, bismuth oxide, cerium oxide, tin oxide, magnesium oxide, lithium oxide, Lead oxide, cadmium sulfide, zinc sulfide, antimony sulfide, cadmium selenide, cadmium telluride, calcium fluoride, sodium fluoride, trisodium aluminum fluoride, lithium fluoride, magnesium fluoride and the like can be suitably used.

As the metal, silver, cobalt, nickel, iron and alloys thereof can be appropriately used.

Hereinafter, the film formation method of the said optical coherent multilayer film is demonstrated.

As the film forming method, both the metal compound film and the metal film can be deposited by vapor deposition such as PVD method, CVD method or spray dry method on the surface of the magnetic particles to directly deposit a metal film or a metal compound film.

In addition, as for the metal film, a so-called chemical plating method is also possible in which magnetic body particles are added to an aqueous metal salt solution and metal salts are reduced in a liquid to precipitate metal on the surface of the magnetic body particles.

In addition, in order to meet the demands of high resolution at present, it is necessary to refine the magnetic toner and to refine the magnetic body particles to form a uniform film on the surface of the magnetic body particles. Therefore, particularly for metal oxides, the film formation method described in the above-mentioned Patent Publication No. 6-228604, Patent Publication No. 7-90310 or WO96 / 28169 proposed by the present inventors is preferable.

That is, the magnetic particles are dispersed in the metal alkoxide solution, the metal alkoxide is hydrolyzed to produce a uniform thin film of the metal oxide on the surface of the magnetic particles, and the drying step is repeated or the metal thin film is formed as necessary. The step may be provided before or after the film forming step of the metal oxide film to obtain a multilayer film composed of metal oxide films or a metal oxide film and a metal film. As the metal alkoxide, alkoxides such as zinc, aluminum, cadmium, titanium, zirconium, tantalum, silicon, antimony, neodium, lanthanum, bismuth, cerium, tin, magnesium, lithium, and lead are selected.

In addition, the heat treatment of the multilayer film can increase the reflectance or make the multilayer film more dense and stable.

The metal alkoxide method can be applied to the film formation of metal sulfides in addition to the film formation of metal oxides.

At this time, by adjusting the thickness of the metal compound film or the metal film, the magnetic body particles can be colored in a predetermined color. For example, when thin films of metal compounds having different refractive indices are provided in thicknesses corresponding to one-fourth the wavelength of incident light, it is possible to form magnetic particles that reflect all incident light, that is, white.

Therefore, the thickness of each film of the optical coherent multilayer film and the film thickness as the entire multilayer film are set to exhibit a desired color.

Thereafter, by setting the organic polymer film for the binder on the surface of the multilayer film-coated magnetic particle, a color magnetic toner colored in vivid color is obtained.

As the method of forming the organic polymer film, a method of coating the organic polymer film directly on the surface of the multilayer-coated magnetic particle by the PVD method, the CVD method, or the spray dry method may be used, but in the present invention, in order to improve the adhesion, It is preferable to form a film by

As such a polymerization method, the suitable polymerization method can be suitably selected according to the kind of organic polymer. Specifically, emulsion polymerization method, suspension polymerization method, seed polymerization method, in-situ polymerization method and the like can be adopted depending on the type of organic polymer. In addition, depending on the type of organic polymer, a phase separation method may be employed.

The organic polymer that can be used is not particularly limited as long as the film can be formed by the polymerization method described above among those used as the binder resin of the magnetic toner. For example, the following polymers:

That is, aromatic hydrocarbon oligomers and polymers such as polystyrene, styrene and α-methylstyrene copolymers, styrene and vinyltoluene copolymers, olefin oligomers and polymers such as polypropylene, polyethylene, polybutene, ethyl acrylate, methyl methacrylate, Vinyl oligomers and polymers made of copolymers of monomers such as ethyl methacrylate, acrylonitrile, polyacrylic acid, polymethacrylic acid and vinyl acetate, or diene oligomers, polyesters such as polybutadiene, polypentadiene, and polychloroprene Oligomer homopolymers such as ester oligomers or copolymers of these oligomers, a plurality of monomers such as hydrocarbon monomers and oligomers, olefin oligomers, vinyl monomers and oligomers, polychloroprene monomers and oligomers, ester monomers and oligomers. Me oligomer The alkyd resin and the like, such as a copolymer, natural lead, polyethylene wax, and the like of the wax, and other rosin-modified alkyd resin to be formed are used.

The coating amount of the organic polymer film is an amount spreading when the color magnetic toner adheres to the ground so as not to cause dropping or peeling, and in view of the colorant described later, about the amount of the magnetic particles occupying the surface when the colored magnetic toner adheres to the ground. It is preferable to set it as the quantity which spreads about four times.

The color magnetic toner of the present invention is characterized in that the color coherent multilayer film provided on the magnetic particles exhibits vivid colors by interfering with the incident light. Therefore, the organic polymer film only needs to have a function as a binder and may be transparent. However, since a color missing part occurs due to the gap between magnetic particles when the color magnetic toner adheres to the ground, the organic polymer film contains a colorant. It is desirable to color the periphery of the toner adhesion portion by spreading the organic polymer film due to adhesion.

Examples of the coloring agent for coloring the organic polymer film include yellow, magenta, and cyan-based coloring agents, and the following organic dyes and organic pigments may be used.

Organic dyes

a. Yellow type: Monoazo dye type, Azomethine type dye, Oil type dye etc.

b. Magenta-based: thioindigo dyes, chianthene-based dyes, 2,9-kinacridone dyes, oil-based dyes and the like.

c. Cyan-based: Copper phthalocyanine-based dyes, oil-based dyes and the like.

Organic pigment

a. Yellow type: Bis azo pigment, Benzidine pigment, Poron yellow pigment, etc.

b. Magenta series: quinacridone pigments, anthraquinone pigments, rhodamine pigments, naphthol insoluble azo pigments and the like.

c. Cyan type: Phthalocyanine type pigment etc.

In addition, the content of these colorants in the organic polymer film is preferably an amount that can be uniformly colored over an area of about 2 times to about 10 times the projected area occupied by the magnetic particles when the color magnetic toner adheres to the ground. .

The color magnetic toner of the present invention is composed of the magnetic particles, the optical coherent multilayer film and the organic polymer film as essential components, and in addition, a charge control agent, a fluidizing agent or a releasing agent can be contained in the organic polymer film.

The charge control agent is an additive added to adjust the chargeability of the color magnetic toner, and organic acids, surfactants, and other dielectric materials are used. Examples of positively charged toners include metal complexes of alkyl salicylic acid, metal complexes of dicarboxylic acid, polycyclic salicylic acid metal salts and fatty acid metal salts. As the secondary toner, quaternary ammonium salts, benzothiazole dielectrics, guanamine derivatives, dibutyltin oxide, nitrogen-containing compounds, chlorinated paraffins, chlorinated polyesters and the like can be used.

The fluidizing agent is an additive added to improve the fluidity of the color magnetic toner and to prevent unnecessary residue on the paper. For example, colloidal silica, aerodyl, titanium oxide powder, alumina powder, and zinc oxide powder. Fatty acid metal salts and the like.

The release agent is an additive added to prevent adhesion of the color magnetic toner to the fixing roll of the developing machine or the like, and for example, low molecular polyethylene, low molecular polypropylene, or the like can be used.

The content of these additives in the organic polymer film is preferably set to an upper limit of about 60% by weight as a total amount. If the content is larger than the above content, practical magnetic properties as a color magnetic toner cannot be obtained.

By combining the above elements, it is possible to provide a vivid color magnetic toner.

As described above, according to the present invention, a multi-layered optical coherent coating film made of a metal compound and / or a metal film is formed on magnetic body particles to form a powder having a white color or a desired color by such a film structure. By forming the organic polymer film for the binder, it is possible to provide a color magnetic toner capable of forming a vivid color image even in one component system.

In addition, the color can be made clearer by including a colorant in the organic polymer film.

As a result, not only the copying apparatus is simplified and miniaturized, but also the coloration of the laser printer and the facsimile of the same principle is possible. Furthermore, in the two-component system, there is no carrier which becomes a waste, and the cost can be reduced, and it is also preferable in terms of environmental conservation.

Claims (5)

A color magnetic toner, wherein an optical coherent multilayer film is formed on particles of a base material made of a magnetic substance, and an organic polymer film is formed on the optical coherent multilayer film. The color magnetic toner according to claim 1, wherein the optically coherent multilayer film reflects light in the visible region. The color magnetic toner according to claim 1 or 2, wherein the organic polymer film contains a colorant. The color magnetic toner according to any one of claims 1 to 3, wherein the optically coherent multilayer film is formed by laminating a metal compound film and / or a metal film in multiple layers. A method of manufacturing a color magnetic toner, wherein an organic polymer film is formed by a polymerization method after forming a multilayer film made of a metal compound and / or a metal on magnetic particles.