JPH01253758A - Encapsulated magnetic toner and production of same - Google Patents

Abstract

PURPOSE:To obtain an encapsulated magnetic toner having a sharp color by covering a core material with a shell material obtained by dispersing an inorganic powder into a polymer. CONSTITUTION:The magnetic toner having a sharp color can be obtained by covering the core material 1 having the color of the magnetic particles and hiding said color with the shell material layer 2 prepared by dispersing into the polymer the inorganic powder, such as powders of aluminum, nickel, silver, titanium dioxide, aluminum oxide, zinc sulfide, lead titanate, zirconium oxide, white lead, zinc white, minium, cadmium red, or cadmium yellow, and the color of the magnetic particles of the core material can be effectively hidden by using the inorganic powder having a refractive index of >=1.9.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a magnetic toner used in electrophotographic toners, magnetography mm toners, magnetic printing inks, etc. This invention relates to color magnetic toner and its manufacturing method.

[Prior Art and its Problems] Magnetic toners are used as toners for electrophotography, toners for magnetography, or magnetic toners for magnetic printing.

The color magnetic toner used for electrophotographic toner and magnetography toner is 1 exOa+T-F.
e-rich 0M + or -C which is obtained by kneading and pulverizing magnetic particles such as barium ferrite, polymer and colorant.
known to. (For example, Takashi Nakamura - 1° Development and practical application of toner materials, Japan Science and Technology Information Department, 1985) L
However, since conventional toner simply mixes black or blackish-brown magnetic particles and a colorant, the toner color becomes cloudy and it is not possible to obtain a toner with a clear color. The color images formed using this method were only dull images.

Furthermore, for toners for electrophotography, various encapsulated magnetic toners have been proposed for the purpose of improving pressure fixing properties, improving offset properties, etc.
No. 780 and Japanese Unexamined Patent Publication No. 60-3647 tU are disclosed.

However, the microencapsulated magnetic toner that has been proposed so far has a structure in which magnetic particles as a core material are simply coated with a polymer, or a structure in which a polymer as a core material is coated with C11 particles. Not suitable for color magnetic toner.

In addition, magnetic toner for magnetic printing, which is used for FFI cards, etc., is made by separating magnetic particles and polymers in a solvent.
Prepared by dissolving. The magnetic printing layer produced using the magnetic toner configured as described above is dark brown or brown in color. When concealing or coloring the magnetic printing layer, for example, Japanese Patent Application Laid-Open Nos. 55-12510 and 1982-317
As shown in Japanese Patent No. 07, a metal vapor deposition layer and a colored layer are provided on the magnetic printing layer. However, the magnetic printing layer configured as described above not only requires many manufacturing steps and is expensive, but also has an evaporator layer and a colored layer on the magnetic printing layer, and the magnetic printing layer and the magnetic head for reading. This has the disadvantage that a spacing loss occurs between the two and the read performance deteriorates.

[Means for Solving the Problems] The present invention has been made in view of the above-mentioned current situation, and specifically, it includes at least a layer in which a core material mainly composed of magnetic particles and an inorganic powder are dispersed in a polymer. The present invention provides an encapsulated toner comprising a shell material having the following properties. (In particular, by providing a metal layer on the surface of a core material whose main component is magnetic particles, magnetic particles with excellent hiding properties can be obtained.) Furthermore, the encapsulated magnetic toner of the present invention is made by combining an inorganic powder with a polymerizable monomer or oligomer. By producing the shell material by an interfacial polymerization method using a liquid containing a small amount of (or mixed with), a magnetic toner with uniform particle size can be obtained.

The detailed description of the invention will be explained in further detail using drawings showing embodiments. FIG. 1 schematically shows a cross-sectional view of an embodiment of an encapsulated magnetic toner.

In Figure 1, a core material (1) whose main component is magnetic particles.
As the magnetic particles, a single magnetic particle, a mixture of several types of magnetic particles, or a powder composed of magnetic particles and a polymer can be used. Here, as the magnetic particles, ferrite,
Examples include magnetite and other magnetic metals such as iron, cobalt, and nickel, or alloys or compounds containing these elements. When using a powder made of magnetic particles and a polymer as the core material (1), the above-mentioned magnetic particles and polymer may be kneaded and then pulverized.

Furthermore, as a more preferable embodiment of the present invention, as shown in FIG. 2, a metal layer (4) is formed on the surface of a powder (3) mainly composed of magnetic particles having the same structure as the core material (+) described above. By providing this, it is possible to improve the hiding property and obtain a clear colored magnetic toner. Here, the metal layer (4) is a core material (5) formed by directly coating the surface of the above-mentioned powder (3) mainly composed of <61 particles as shown in FIG.
As shown in FIG. 3, the core material (7) may have a structure in which the surface of the powder (3) described above is coated with a polymer layer (6) and then a gold layer (4) is provided. and the polymer J! between the metal layer (4) and the metal layer (4). ! Not only can gold El be coated uniformly and with good adhesion by using powder (3)
The metal layer (
4). As the metal used here, aluminum, tin, nickel, cobalt, or various metal alloy rings - the most known metals are used.

Powder (3) or powder having a polymer layer (6) (
As a method for coating 3) with a metal layer (4), a method of chemically adsorbing or physically adsorbing an organometallic compound on the surface of the core material, and then decomposing the organometallic compound to obtain a metal layer;
Or, after dispersing the core material in an aqueous solution containing metal hydroxide, adjust the pH! I! A method of obtaining a metal layer by knotting and depositing on the surface of the core material and drying or firing, a method of electroless plating, etc. can be used.

In particular, the method of forming a metal layer by electroless plating has the advantage that a metal layer that is uniform and has an arbitrary thickness can be obtained.

In addition, by covering the core materials (1), (5), and (7) with a layer (2) in which inorganic T5) powder is dispersed in a polymer, the color of the magnetic particles constituting the core material can be changed. A concealing and clear color magnetic toner can be obtained. The inorganic powders used here include metal powders such as aluminum powder, aluminum powder, silica powder, and powder, titanium dioxide, aluminum oxide, zinc sulfide, lead titanate, zirconium oxide, white lead, zinc white, and red lead. - Cadmium red, cadmium yellow, etc. can be used, but are not limited to these, and various inorganic powders can be used. In particular, by using an inorganic powder with a refractive index of 1.9 or more, the color of the magnetic particles that are the core material can be efficiently hidden. Here, as the inorganic powder having a refractive index of 1.9 or more, titanium dioxide, zinc sulfide, lead titanate, zirconium oxide, cadmium red, cadmium yellow, etc. are used. Further, as the polymer for dispersing the above-mentioned inorganic powder, the resin used in -i can be used, for example,
Examples include acrylic resins, polystyrene, polyester resins, epoxy resins, natural resins, etc., and these may be used alone or in combination of two or more, and may be determined depending on desired performance. The content of the pigment in these polymers needs to be appropriately determined depending on the desired shape of the magnetic particles or the type and particle size of the 7-inch material used.The content of the pigment in these polymers is preferably from 5% to 40% by weight, as described above. The layer (2) in which inorganic powder is dispersed in a polymer can be prepared by a phase separation method in which a concentrated phase of the polymer is divided around a core substance dispersed in a polymer solution, Microencapsulation techniques such as the in-liquid curing W IW method in which the polymer is cured with a curing reagent, etc., or the mechanochemical method in which the core substance is mechanically covered with a polymer are suitable, but are limited to these methods. isn't it.

In particular, by manufacturing using an interfacial polymerization method in which a liquid mixture of at least R-free powder and a polymerizable mercury or oligomer is polymerized at the interface of the above-mentioned core material, capsule fossilized toner with uniform particle size can be produced. but! ! ! Can be built.

The polymerizable monomers or oligomers used here are preferably monomers or oligomers such as compounds having an epoxy group, acrylic esters, methacrylic esters, styrene and derivatives thereof.

Furthermore, the surface of the layer 2 in which the inorganic powder constituted as described above is dispersed in a polymer is coated with various polymer layers and colored layers in which various dyes and pigments are dispersed in a polymer to form a shell material. A highly functional encapsulated magnetic toner with offset properties, adhesive properties, dispersion stability, etc. can be obtained.

[Example] The present invention will be specifically explained below using examples.

Example 1 Magnetic particles made of Fezes as a core material (average particle size 0.2 μm) 5 type assembly parts, titanium dioxide (manufactured by Nippon Aerosil Co., Ltd.) 10 parts, Noboran 4301 in polyurethane resin: Japan Polyurethane (11 ) 20 parts by weight,
7 parts by weight of 2,4-toluicine diisocylene, which is a crosslinking material, was dispersed in 200 parts by weight of methyl ethyl ketone i8 liquid using an ultra-high speed homogenizer (Polytron, KINE? 1 manufactured by ATICA) at a rotation speed of 5000 rpm. Drop 9:150 parts by weight of n- into the i8 liquid above to phase-separate the polyurethane resin containing titanium dioxide around the core magnetite, and create a layer in which inorganic powder made of titanium dioxide is dispersed in the polymer. A shell material consisting of After washing the product, the product was officially dried to obtain an encapsulated magnetic toner.Encapsulated magnetic toner 7 configured as above 0
A white ink for magnetic printing was obtained by dispersing 25 parts of Tuboran 4301 (manufactured by Nippon Polyurethane) in a polyurethane resin and 5 parts of 2.4) Luizin diisocyanate in methyl If-ketone.

Example 2 A core material with an average particle size of 1.0 μ was obtained by heating and mixing maleic acid-modified polystyrene (manufactured by Toda Kogyo Department) with magnetic particles having an average particle size of 0.25 μm (IAT305: manufactured by Toda Kogyo ■) and then crushing them. . A metal layer was provided on the surface of the core material by electrolessly plating nickel on the core material. A shell material is formed from the core material configured as described above by interfacial polymerization. That is, 5 g of the core material is mixed with 7 g of colloidal calcium phosphate.
1 F Sodium dacilbenzene sulfurinate 0.
3 g was dispersed in the 4001 aqueous solution using an ultra-high speed homogenizer (Polytron, manufactured by KINEMATICA) at a rotation speed of 12000±1100 Orp. The solution was transferred to a 4-diameter flask and heated at 70°C at 35°C under a nitrogen atmosphere.
While stirring at 0 rpm, add 8 m parts of suderene, 2 parts by weight of cypinylbenzene, and 2-methyl methacrylic acid.
Human Ftl x Iglu 5 parts by weight, A11bi 3
0 parts by weight, Woftinglef F) 10 parts by weight,
Add 0.2 parts by weight of azobisisobutytrinitrile and 42 parts of ethanol to form a layer in which the inorganic powder is dispersed in the polymer. Furthermore, sodium F dacilbenzenesulfonate. 2 parts by weight of styrene, 2-hyperoxyfluoride methyl methacrylic acid (l)
Kishi January 410 parts by weight, Wofting Left 1
5 parts by weight, 7 Zobisisobuty A: ) II 1
A liquid consisting of 10.2 parts by weight was added dropwise, stirred for 1 hour, and then separated and dried to obtain a colored layer. As described above, an encapsulated magnetic toner is obtained by forming a shell material by an interfacial polymerization method.The encapsulated magnetic toner configured as above can be used as a magenta one-component magnetic toner used in electrophotography.

Real hi! i Example 3 5g of magnetic particles of mackerel with an average particle size of 0.25μ (11AT30
5: Coupled with divinylmethoxysilane (manufactured by Toda Kogyohata) and coated with 7 g of F-type calcium phosphate, 87 ounces of F-type calcium phosphate (Mt.)
An ultra-high-speed homogenizer (Polytron, KINE II
AjlcA company! ! Rotation speed 12000±1100
Disperse with Orp. The solution was transferred to a 4-diameter flask, and while stirring at 350 rpm at 70° C. under a nitrogen atmosphere, 8 parts by weight of styrene, 2 parts by weight of divinylbenzene, 1 part of methyl methacrylic acid 2-H-FoH+x+ 5ff, and 0.7 zobisisobutylnitrile were added. 2 parts by weight of liquid 2
g is added dropwise, and then separated and dried after 45 minutes to obtain a substance. By electrolessly coating the core material with nickel, a metal layer is provided on the surface of the core material to obtain a material. 5 g of the material
4 in which 7 g of colloidal Rocheum phosphate and 0.03 g of F.
001 aqueous solution using an ultra-high speed homogenizer (Polytron, manufactured by INEW 8 TI A company) at a rotation speed of 12000±1.
Disperse at 000 rpm+m. The solution was transferred to a 4-diameter flask, and while stirring at 70°C and 350 rpm under a nitrogen atmosphere, 2 parts by weight of styrene, 2 parts by weight of divinytribenzene, and 5 ff of 2-hyphenylmethylmethacrylate were added.
i parts, 7zobisisobutyl di) 0.2. , titanium dioxide (manufactured by Nippon Aerosil Co., Ltd.) 2 (lffi parts, eta/-140 parts by weight) was added, and the mixture was stirred for 1 hour to form a layer in which the inorganic powder was dispersed in the polymer. Disperse 0.03 g of sodium F-decylbenzecisulfonate in ゛, 2 parts by weight of styrene, and 1 l of 2-7F xyethyl methyl methacrylate.
O Parts by weight, Lid ■Schiff = Sample-2 5 Parts by weight,
A liquid consisting of 80.2 parts by weight of 7zobisbutylnitrines was added dropwise, stirred for 1 hour, and then separated and dried.

As described above, an encapsulated magnetic toner is obtained by forming a shell material by an interfacial polymerization method.The encapsulated magnetic toner having the above structure can be used as a cyan toner used in magnetography.

[Effects of the Invention] The present invention is as described above, and it is possible to obtain an encapsulated magnetic toner that does not cause turbidity due to the color of the magnetic particles that are the core material and has a clear color. Colors used in toners for graphics and magnetic inks for magnetic printing (can be used for n-type toners. In particular, by coating the surface of magnetic particles with a metal layer, encapsulated magnetic toner with excellent hiding properties can be obtained. Furthermore, by manufacturing by interfacial polymerization, an encapsulated magnetic toner with uniform particle size can be obtained, which is of great industrial value.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of the encapsulated magnetic toner of the present invention, and FIGS. 2 and 3 are sectional views showing examples of the core material used in the encapsulated magnetic toner of the present invention. be. (1), (5), (7): Core material mainly composed of Si2 particles (2); Layer in which inorganic powder is dispersed in polymer (3): Powder (4): Metal layer (6): polymer layer

Claims (3)

[Claims] (1) An encapsulated magnetic toner consisting of a core material mainly composed of magnetic particles and a shell material covering the new material, characterized in that the shell material has at least a layer in which inorganic powder is dispersed in a polymer. Encapsulated magnetic toner. (2) The encapsulated magnetic toner according to claim (1), characterized in that a metal layer is provided on the surface of the core substance whose main component is magnetic particles. (3) A method for producing an encapsulated magnetic toner, which comprises producing the shell material by interfacial polymerization using a liquid mixture of at least an inorganic powder and a polymerizable monomer or oligomer.