JPH0273367A - Magnetic toner for color and its preparation - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a color magnetic toner used in electrophotography and a method for producing the same.

[Conventional technology]

Conventionally, as an electrophotographic method, US Pat. No. 2,297,139
Many methods have been proposed so far based on the Carlson process shown in 1.

Generally, an electrostatic latent image is formed on a photoreceptor using a photoconductive substance, and then a fine powder called "toner" is selectively attached to the latent image, and development is performed to make the latent image visible. Visualize. The visualized toner is transferred to a transfer material such as paper if necessary, and then fixed by heat and pressure, solvent vapor, etc. to obtain an image-formed product.

Development methods can be broadly classified into dry development methods and liquid development methods, and further known dry development methods include two-component development methods that use a carrier, such as magnetic brush development and cascade development. Furthermore, as the -component development method, there are known jumping development method, FEED development method, magnetic brush development method, and the like. Generally, the toner used in these developing methods contains colorants such as dyes and pigments in the resin.
Fine particles of approximately 10 μm in size in which a charge control agent and the like are dispersed and a fluidity improver and the like are externally attached thereto are used.

In addition, recently, colorization, miniaturization of equipment, lower cost,
Due to demands such as maintenance-free toner, various demands are placed on toner.

Among these, there is a strong demand for color toners to have magnetism. Until now, it has been proposed to whiten or color magnetic toner. It is disclosed that a color magnetic toner is obtained by forming a coating layer containing a colored pigment on the surface of an outer hiding layer.

[Problem to be solved by the invention]

However, in the above-mentioned method, the colorant is contained only on the surface of the toner, so when it is fixed, the original colorant tone becomes cloudy and dark brown due to the magnetic particles contained in the core particles. Put it away. Furthermore, the contents of the magnetic agent and colorant cannot be adjusted arbitrarily. Another problem is that the manufacturing method is complicated because the core particles, hiding layer, and colored layer are formed by a polymerization method, a spray drying method, or the like.

Therefore, it is an object of the present invention to solve the above-mentioned problems, and to create a color magnetic toner that has sufficient magnetic force as a magnetic toner, and that can sufficiently produce the original color tone of the colorant without clouding the color due to magnetic particles. An object of the present invention is to provide a toner and a method for easily producing the color magnetic toner.

[Means to solve the problem]

The color magnetic toner of the present invention is characterized by using colored magnetic particles having a concealing layer made of a white substance on the surface of the magnetic particles and further having a coloring agent fixed to the surface of the concealing layer.

Further, the manufacturing method of the present invention is characterized in that the formation of the hiding layer and the fixation of the colorant to the surface of the hiding layer are performed by mechanochemical reaction.

[Effect]

By completely covering the surface of the magnetic particles with a white substance, absorption of light by the magnetic particles can be prevented. Furthermore, since the particle size of a coloring agent is generally very small, the surface of the magnetic particles cannot be completely covered with the coloring agent alone. For this reason, it is necessary to form a concealing layer between the magnetic particles and the colorant using a white substance whose particle size is larger than that of the colorant.

Furthermore, since the adhesion force between magnetic particles and a white substance alone is small, a resin is used as a binder. Furthermore, this resin also serves as a binder for the colorant, since the adhesion force is similarly weak even when only the white substance and the colorant are used.

There are many unknowns about the mechanochemical reaction that fixes the hiding layer and colorant to the magnetic particles, but since this reaction uses both thermal and mechanical energy, the powder particle mixture is It becomes very active, and for this reason, uniform mixing occurs, and the resin and white substance or coloring agent adhere uniformly around the magnetic particles, and then a film is formed or fixed by heat. it is conceivable that.

〔Example〕

The present invention will be specifically explained by the following examples.

As the magnetic particles used in the present invention, those used in ordinary toners can be used. For example, F e 30
J, Fears, Fe%Cr%Ni, Co, ferrite, etc.

In addition, white matter and shite are S i Os, T i 02
(rutile, anatase), Z n O, A 1203
((Z, β type), TiBa0s, MgO1ZrOz
, CaCO3, NiO, SnO, clay talc, etc.

Further, in order to form a concealing layer, a resin is used as a binder for the white substance. The resin is not particularly limited, but thermoplastic resins are preferred.

For example, polystyrene and copolymers, hydrogenated styrene resins, styrene-isobutylene copolymers.

ABS resin, ASA resin, As resin, AAS
As resin C3 resin, ABS resin, styrene/P-chlorostyrene copolymer, styrene/propylene copolymer, styrene/butadiene crosslinked polymer, styrene/butadiene/chlorinated paraffin copolymer, styrene/allyl/alcohol copolymer, styrene・Butadiene rubber emulsion, styrene/maleic ester copolymer, styrene/isobutylene copolymer, styrene/maleic anhydride copolymer, acrylate resin or methacrylate resin and its copolymer, styrene/acrylic resin and copolymers thereof, such as styrene/acrylic copolymer, styrene/diethylamino/ethyl methacrylate copolymer, styrene/butadiene/acrylate ester copolymer, styrene/methyl methacrylate copolymer, styrene/n- Butyl methacrylate copolymer, styrene/diethylamino/ethyl methacrylate copolymer, styrene/methyl methacrylate/n-butyl acrylate copolymer, styrene/methyl methacrylate/butyl arylate/N-(ethoxymethyl)acrylamide copolymer Coalescence, styrene/glycidyl methacrylate copolymer, styrene/butadiene/dimethyl/aminoethyl methacrylate copolymer, styrene/acrylic acid ester/maleic ester copolymer, styrene/methyl methacrylate/2-ethylhexyl acrylate Copolymer, styrene/n-butyl arylate/ethyl glycol methacrylate copolymer, styrene/n
-butyl methacrylate/acrylic acid copolymer, styrene/n-butyl methacrylate/maleic anhydride copolymer, styrene/butyl acrylate/isobutyl maleic acid half ester/divinylbenzene copolymer,
Polyester and its copolymers, polyethylene and its copolymers, epoxy resins, silicone resins, polypropylene and its copolymers, fluorocarbon resins, polyamide resins,
One type or a blend of two or more types of polyvinyl alcohol resin, polyurethane resin, polyvinyl butyral resin, etc. can be used.

As the colorant, those used in general color toners can be used. . For example, (yellow) benzidine yellow, sloin yellow, microlith yellow, naphthol yellow, Hansa yellow, quinoline yellow lake (magenta), quinacridone, rhodamine B lake, polytungstophosphoric acid, carmine 6B (cyan), phthalocyanine blue, industhrene blue, oil blue, sulfonamide derivatives, Indigo, Alkali Blue (Red) Microlith Red, Soubron Red, Red Red, Eosin Lake, Thioindigo (Green) Phthalocyanine Green, Microlith Green CT,
malachite green lake, acid green lake,
Pigment Green B, Naphthol Green B, etc. can be used.

Methods for forming a concealing layer made of a white substance on the surface of magnetic particles using the above raw materials include spray drying,
Performed by mechanochemical method.

In the case of spray drying, the resin is dissolved in a suitable solvent,
Magnetic particles and a white substance are added to the mixture, dispersed, and spray-dried. Further, in the case of the mechanochemical reaction method, it is sufficient to simply mix the magnetic particles, the white substance, and the resin, and the treatment temperature in the mechanochemical reaction at this time is carried out at a temperature higher than the glass transition temperature of the resin used. If the temperature is below the glass transition temperature, it is impossible to form a hidden layer containing a white substance on the surface of the magnetic particles.

Next, a coloring agent is added to the magnetic particles on which a concealing layer made of a white substance has been formed, and the coloring agent is fixed to the surface of the concealing layer made of a white substance by a mechanochemical reaction. At this time, the mixing ratio is adjusted so that the coverage of the colorant over the entire area of the concealing layer of the magnetic particles, that is, on the surface of the concealing layer, is 100% or more. In addition, the treatment temperature in the mechanochemical reaction when fixing the colorant is below the glass transition temperature of the resin used. If it is above the glass transition temperature, the magnetic particles with the hiding layer will aggregate, resulting in coloring. However, the agent cannot be fixed efficiently. As a method for carrying out the mechanochemical reaction, a so-called high-speed fluidized stirrer is used. For example, the Mechanofujimin system (manufactured by Micron for wires), the Nara hybridization system (manufactured by Nara Kikai Seizo Shin), etc. can be used.

However, the apparatus for carrying out the mechanochemical reaction is by no means limited to these, and any apparatus other than the above-mentioned apparatus may be used as long as it is capable of applying mechanical and thermal energy.

The method for coloring magnetic particles in any color has been described above, and it is preferable that the resin used therein be as fine as possible. Furthermore, the white substance needs to have a smaller particle size than the magnetic particles.

As a method for producing a color magnetic toner using colored magnetic particles produced using the raw materials and production method described above, a known kneading and pulverization method, spray drying method, polymerization method, etc. can be used.

When used as a toner, the binder resin is not particularly limited, and those used as the binder for the white substance described above can also be used. In addition, dispersants include metal soaps and polyethylene glycol, charge control agents include electron-accepting organic complexes, quaternary ammonium salts, and pyridinyl salts, and fluidity improvers include silica, titanium oxide, and talc. , clay, etc. can be added.

This example will be explained in more detail below.

[Example 1] [Formation of hidden layer] FezOa 150 parts by weight T
25 parts by weight of iO2 2 parts by weight of polybutyl methacrylate (PBMA) particles were roughly mixed together, and PB was applied to the surface of Fe5Oa using a mechanofusion system (manufactured by Micron for wires).
A concealing layer is formed in which TiO2 is dispersed using MA as a binder.

The particle size of Fe3O4 is 1.5 μm, and the particle size of TiO2 is 10n.
m, PBMA is 0.2 μm. Further, the treatment temperature for the mechanochemical reaction was 90°C. (The glass transition temperature of PBMA is 85°C.) As a result, Fe5O
A concealing layer was formed on the surface of No. 4.

[Adhesion of colorant]

Next, cyan-colored magnetic particles were produced using Fe sOa, which had formed the above-mentioned concealing layer, and a phthalocyanine pigment as a coloring agent.

Hiding layer Fe3O4 160 parts by weight Phthalocyanine pigment 20 parts by weight Using the above raw materials, the phthalocyanine pigment was fixed on the surface of the hiding layer Fe3O4 using the mechanofusion system in the same manner as in [Formation of the hiding layer]. At this time, the surface coverage of the phthalocyanine pigment was set to 100%. Furthermore, the mechanochemical reaction treatment temperature was 80°C. The resulting magnetic particles exhibited a clear cyan color.

[Preparation of color magnetic toner]

A toner was produced using the above magnetic particles having a cyan color.

Styrene/acrylic resin 60 parts cyan Fe5Oa 40 parts by weight Using the above raw materials, a toner having a particle size of 5 to 20 μm was produced by a well-known cross-wire pulverization method.

When the cyan toner prepared above was loaded into a laser printer having a one-component non-contact developing device and an OPC photoreceptor and an image was formed, a clear cyan image could be formed.

[Example 2] [Formation of hidden layer] A hidden layer was formed using the same raw materials and manufacturing method as in Example 1.
5Os was produced.

[Adhesion of colorant]

The same procedure as in Example 1 was carried out. However, Rhodamine B lake was used as the coloring agent.

[Preparation of color magnetic toner]

The same procedure as in Example 1 was carried out. Note that image formation was performed in the same manner as in Example 1, and a clear magenta image could be formed.

[Example 3] [Formation of hidden layer] A hidden layer was formed using the same raw materials and manufacturing method as in Example 1.
30a was produced.

[Adhesion of colorant]

The same procedure as in Example 1 was carried out. However, a benzidine derivative was used as the coloring agent.

[Preparation of color magnetic toner]

The same procedure as in Example 1 was carried out. Note that image formation was performed in the same manner as in Example 1, and a clear yellow image could be formed.

[Example 4] The hiding layer produced in Example 1 had a multilayer structure in this example.

[Formation of hidden layer]

<5TEP1> Fe30a 150 parts by weight Polybutyl methacrylate (PBMA) particles 4 parts by weight The above raw materials were mixed, and a PBMA film was formed on the surface of the Fe30a particles by mechanochemical reaction in the same manner as in Example 1. The thickness of the PBMA film was about 061 μm. The treatment temperature for the mechanochemical reaction was 90°C.

<5TEP2> Next, T was applied to the Fe5Oa particles on which the PBMA film was formed.
iO2 was fixed.

PBMA-coated FeaO 4150 parts by weight TiO 25 parts by weight The above raw materials were mixed and PBM was formed by mechanochemical reaction.
TiO2 was fixed on the surface of the A coating layer. The TiO2 coverage was approximately 100%, and the mechanochemical reaction treatment temperature was 90°C.

<5TEP3> Next, a PBMA film was further formed on the magnetic particles to which the Tioa particles were fixed.

Tie2 fixed Fe5Oa 150 parts by weight PB
MA 4 parts by weight The above raw materials were mixed to form a PBMA film in the same manner as in 5TEP 1.

As described above, a hidden layer was formed on the surface of Fe5O4 particles using 5TEP1 to 3.

Hereinafter, [fixation of colorant] and [preparation of color magnetic toner] were carried out in the same manner as in Example 1, Example 2, and Example 3. As a result, cyan, magenta, and yellow magnetic toners were produced. Furthermore, when images were formed in the same manner as in Example 1, clear cyan, magenta, and yellow images could be formed as in Example 1.

[Example 5] A concealing layer was formed on the surface of the Fe5O4 particles by a spray drying method.

Using the composition and raw materials used in [Formation of Hiding Layer] in Example 1, the composition was dissolved and dispersed in toluene so that the solid content was 15%. This toluene dispersion solution was spray-dried to give Fe3
A hidden layer was formed on the surface of the O4 particles. The spraying method used a two-fluid nozzle. The spray conditions are pressure 4kg/cm”
, and the drying temperature was 75°C. As a result, a hidden layer was formed on the Fe1Oa surface.

Hereinafter, [fixing of colorant] and [preparation of color magnetic toner] were carried out in the same manner as in Example 1, Example 2, and Example 3. As a result, cyan, magenta, and yellow magnetic toners could be produced. Furthermore, when images were formed using a laser printer using a one-component magnetic brush development method using these toners, clear cyan, magenta, and yellow images were formed as in Examples 1, 2, and 3. We were able to.

[Example 6] Using the cyan, magenta, and yellow magnetic toners produced in Examples 1 to 5, -component magnetic brush development method and OP
When a full-color image was formed using a well-known electrophotographic process using a C photoreceptor through the steps of 3 exposures, 3 development steps, 3 transfer steps, and fixing, a clear full-color image could be formed.

Although the embodiments of the present invention have been described above, the color magnetic toner and manufacturing method of the present invention are not limited to these embodiments.

[Effects of the Invention] As described above, the color magnetic toner of the present invention has a concealing layer made of a white substance on the surface of magnetic particles, and further has a coloring agent fixed to the surface of the concealing layer. Use colored magnetic particles. Furthermore, by forming the concealing layer and fixing the colorant to the surface of the concealing layer through a mechanochemical reaction, it is possible to sufficiently combine both magnetic force and coloring power, and furthermore, the original color tone of the colorant can be reproduced by magnetic particles. This has the effect of providing a color magnetic toner with excellent color reproduction without causing any damage.

Further, according to the manufacturing method of the present invention, the coloring of the magnetic particles can be carried out in a short time and with energy savings, and furthermore, the colored magnetic particles can be used to make a color magnetic toner by a normal toner manufacturing method. This has the effect of providing an inexpensive color magnetic toner.

Furthermore, the color magnetic toner and manufacturing method of the present invention include:
It can be applied to color image forming devices using electrophotography, electrostatic recording, electrostatic printing, magnetic recording, etc., such as color copying machines, color printers, and color facsimiles.

Furthermore, the colored magnetic particles of the present invention can be used not only in electrophotographic toners but also in those using other magnetic particles. This has a very large effect in that what was previously black or blackish brown can be colored.

that's all Applicant: Seiko Epson Corporation Agent: Patent Attorney Suzumi Do, Kisanbe, and 1 other person

Claims (2)

[Claims] (1) A color magnetic toner characterized by using colored magnetic particles having a concealing layer made of a white substance on the surface of the magnetic particles and further having a coloring agent fixed to the surface of the concealing layer. (2) A manufacturing method characterized in that the formation of the hiding layer according to claim 1 and the fixing of the colorant to the surface of the hiding layer are carried out by mechanochemical reaction.