JPH01100561A - Pressure fixable capsule toner - Google Patents

Abstract

PURPOSE:To improve the release property of a capsule toner from a press roller by incorporating fine powder treated with a silicone oil into a core material. CONSTITUTION:This capsule toner contains the fine powder pretreated with the silicone oil in the core material. More specific examples of the silicone oil to be used for treating the fine powder incorporated into the core material are a series of silicone oils, etc., as represented by dimethyl silicone oil and methyl phenyl silicone oil. The fine powder is treated by such silicone oils. The release property of the toner from the press roller is thereby improved and the sticking of the toner to the roller in a fixing stage is prevented; in addition, the dispersibility of the fine powder in the pressure fixable component is enhanced and the homogeneous capsule toner which obviates offset development is obtd.

Description

[Detailed Description of the Invention] [Industrial Technical Field] The present invention relates to a toner used for developing an electrical latent image in electrophotography, electrostatic printing, etc.
In particular, it relates to a capsule toner suitable for pressure fixing.

[Prior Art] Conventionally, as an electrophotographic method, U.S. Patent Section 2,297°68
1 Specification, Japanese Patent Publication No. 42-23910 (U.S. Patent Section 3.1 (Specification No. 1313,383)) and Japanese Patent Publication No. 43
A number of methods are known, such as those described in U.S. Patent No. 4.071.381 (U.S. Pat. Forming an electrical latent image on a photoreceptor, then developing the latent image using toner, transferring the toner image to a transfer material such as paper as necessary, and then fixing it to obtain a copy. The process is taken.

To fix a toner image, a heat fixing method is generally used in which the toner image is heated and melted using an infrared heater or a heated roller, and then fused and solidified to the support. For these reasons, there is a shift toward a pressure fixing method using a rigid roller, which does not require heating or has a reduced wood quality. In particular, this pressure fixing method has the following advantages: there is no risk of burning copy sheets, copying can be done without waiting time when the copier is turned on, high-speed fixing is possible, and the fixing device is simple. There are many advantages such as.

In particular, for toners that can be fixed by pressure, the constituent resin must have properties suitable for pressure fixing, and resins that meet this purpose are actively being developed. ing. However, it has excellent pressure fixing properties, does not cause any offset phenomenon to the pressure roller, and has stable developing and fixing performance even after repeated use. A practical pressure fixing toner with good storage stability that does not cause agglomeration or caking during storage has not yet been obtained. In particular, the offset phenomenon is a big problem in that the toner adhering to the pressure roller contaminates the transfer paper.

We have developed various characteristics required for pressure fixing toners.
Various capsule-type toners provided with hard resin shells have been proposed in order to satisfy the requirements by multi-layering toner particles.

Such proposals include, for example, a capsule toner having a core of a soft material as seen in Japanese Patent Publication No. 54-8104 (U.S. Patent No. 3,788°994), or a soft resin solution. Although there is a core capsule toner, there are many unresolved problems such as the offset phenomenon caused by the destruction of the shell material by the pressure roller, and it has not been put into practical use.

On the other hand, especially in capsule toners, it is considered difficult to uniformly disperse fine particles of coloring material, magnetic material, etc. in the core material. As mentioned above, soft or liquid materials are used as core materials for capsule toners, but when dispersing fine particles in these materials, the dispersion force exerted on the fine particles is higher than that of ordinary resins. is small and difficult to disperse uniformly. Particularly, when the fine particles are strongly secondary agglomerated, uniform dispersion is almost impossible.

If a capsule toner is manufactured using a core material in which fine particles are dispersed non-uniformly, there will be a large difference in the content of colored fine particles among the toner particles, resulting in uneven density such as spots on the copied image. This causes the formation of toner, making it practically impossible to use it as a toner.

In addition, until now, the inclusion of silicone oil in the core material of capsule toner to improve mold release properties was disclosed in Japanese Patent Application Laid-Open No. 55
Although it is proposed in Japanese Patent No. 14236, no attempt has been made to simultaneously satisfy both fine particle dispersibility and offset using silicone oil.

[Object of the Invention] An object of the present invention is to provide a pressure-fixable capsule toner that overcomes the above-mentioned drawbacks.

Specifically, the purpose is to improve the releasability of the capsule toner from a pressure roller by incorporating fine powder treated with silicone oil into the core material, and to provide a homogeneous pressure-fixable capsule toner without offset development. .

Another object of the present invention is to improve the dispersion of the fine powder into the core material by treating the fine powder with silicone oil, thereby providing a copy image free from stain-like density unevenness.

Another object of the present invention is to provide a capsule toner that maintains its initial characteristics even when used continuously for a long period of time, and has no toner aggregation or change in charging characteristics.

[Means for Solving the Problems] The capsule toner of the present invention was developed to achieve the above-mentioned object, and includes a core material containing a pressure fixing component and a core material that covers at least one of the core materials. A capsule toner comprising an outer shell is characterized in that the core material contains fine particles that have been previously treated with silicone oil.

The present invention will be explained in more detail below.

The core material of the capsule toner of the present invention is basically made by dispersing a colorant and, if necessary, a fine powder of magnetic powder in a pressure fixing component and pulverizing the core material. As the pressure fixing component constituting the core substance, any soft solid substance that exhibits favorable fixing properties can be used.Such substances include waxes (beeswax, carnauba wax, paraffin wax, microcrystalline wax, etc.) , higher fatty acids (stearic acid, palmitic acid, lauric acid, etc.), higher fatty acid metal salts (aluminum stearate, lead stearate, barium stearate.

Magnesium stearate, zinc stearate.

zinc palmitate, etc.), higher fatty acid derivatives (methyl hydroxystearate, glycerol monohydroxystearate, etc.), polyolefins (low molecular weight polyethylene, low molecular weight polypropylene, polyethylene oxide, polyisobutylene, polytetrafluoroethylene, etc.) and these polyolefins. Chemical reaction products with amino group-containing monomers, olefin copolymers (ethylene-acrylic acid copolymers, ethylene-acrylic acid ester copolymers, ethylene-
methacrylic acid copolymer, ethylene-methacrylic acid ester copolymer, ethylene-vinyl chloride copolymer, ethylene-vinyl acetate copolymer, ionomer resin, etc.), styrenic resin (low molecular weight polystyrene, styrene-butadiene copolymer) (Monomer weight ratio 5-30:95-70)
, styrene-acrylic compound copolymers, etc.), epoxy resins, polyester resins (acid value 10 or less), rubbers (
(inbutylene rubber, nitrile rubber, chloride rubber, etc.), polyvinylpyrrolidone, polyamide, coumaron-indene resin, methyl vinyl ether-maleic anhydride copolymer, maleic acid-modified phenol resin, phenol-modified terpene resin, silicone resin, etc. These can be used alone or in combination.

Further, the fine powder constituting the core substance is a coloring agent, magnetic powder 9, etc.

Such coloring agents include conventionally known pigments.

For example, various organic pigments such as anthraquinone series, quinacridone series, phthalocyanine series, perylene series, perinone series, azo series, etc., various inorganic pigments such as titanium oxide, iron oxide, yellow lead 2 ultramarine, and navy blue, and various metal oxides other than these. Metal compounds such as metals, metal chlorides, mixtures thereof, and metal complexes can be used.

These colorants are generally used to obtain capsule toners for two-component developers, and are preferably added in an amount of 0.5 to 15 parts by weight per 100 parts by weight of the pressure fixable component.

Further, as the magnetic powder, a substance that is magnetized when placed in a magnetic field is used, and includes powders of ferromagnetic metals such as iron, cobalt, and nickel, and alloys and compounds such as magnetite, hematite, and ferrite. This magnetic powder may also be used as a coloring agent.

These magnetic powders are generally used to obtain a one-component magnetic toner, and are used in amounts of 50 to 100 parts by weight per 100 parts by weight of the pressure fixable component.
It is added in an amount of 80 parts by weight.

Specific examples of the silicone oil used to treat the fine powder contained in the core material of the capsule toner in the present invention include a series of silicone oils typified by dimethyl silicone oil and methylphenyl silicone oil; Examples include modified silicone oils such as amine-modified silicone oil, α-methylstyrene-modified silicone oil, alkyl-modified silicone oil, alcohol-modified silicone oil, and polyether-modified silicone oil.

By treating the fine powder with the silicone oil,
The releasability of the toner of the present invention from the pressure roller is improved, the toner is prevented from adhering to the roller in the fixing process, and the dispersibility of fine powder in the pressure fixing component is also improved, and offset development A homogeneous capsule toner can be prepared.

The amount of silicone oil added is 1.0 to 30 parts by weight, preferably 2.0 to 30 parts by weight, per 100 parts by weight of the fine powder.
The amount is in the range of 25 parts by weight, and if the amount added is less than 1.0 parts by weight, sufficient effects on mold release and dispersibility cannot be obtained.
If it exceeds 30 parts by weight, traces of silicone oil seepage will be clearly seen near the image on the copy sheet fixed by the pressure roller, which is not preferable.

As a specific method for treating the fine powder used in the present invention with silicone oil, for example, a flask equipped with a stirrer, a thermometer, and a dropping funnel is set on a hot plate, and a flask suitable for the fine powder is used. A preferred method is to gradually add silicone oil while applying shear and, if necessary, heat to loosen aggregates of fine powder.

The core material of the capsule toner of the present invention can be obtained by, for example, melting and kneading the above-mentioned components, granulating them with a spray dryer, and further classifying as necessary, so that the volume average particle diameter is 5 to 5.
Prepared as 20 JL microparticles.

The capsule toner of the present invention is prepared by covering the core material particles obtained as described above with a shell material.

Known resins can be used as the shell material, for example,
There are resins made of the following monomers. Styrene, P
-Chlorstyrene.

Styrene and its substituted products such as P-dimethylamino-styrene; methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate.

Acrylic acid or methacrylic acid esters such as ethyl methacrylate, butyl methacrylate, methacrylic acid N, N-dimethylamine ethyl ester: maleic anhydride or /\-phester of maleic anhydride, half amide or diesterimide, vinylpyridine, N-
Nitrogen-containing vinyls such as vinyl imidazole; vinyl acetals such as vinyl formal and vinyl butyral; vinyl monomers such as vinyl chloride, acrylonitrile, and vinyl acetate; vinylidene monomers such as vinylidene chloride and vinylidene fluoride; olefin monomers such as ethylene and propylene. . Also polyester, polycarbonate, polysulfonate.

Polyamide, polyurethane, polyurea, epoxy resin, rosin, modified rosin, terpene resin.

Homopolymers, copolymers, or mixtures of phenolic resins, aliphatic or alicyclic hydrocarbon resins, aromatic petroleum resins, melamine resins, polyether resins such as polyphenylene oxide, or thioether resins can be used. .

To obtain a capsule toner having an outer shell made of these polymers,
Various known encapsulation techniques can be utilized.

For example, spray drying method, liquid drying method, phase separation method, etc. can be suitably used, as well as 1n-situ polymerization method, U.S. Pat. No. 3,338,991, U.S. Pat. No. 3,326.
The methods described in Japanese Patent No. 848 and Japanese Patent No. 3,502,582 can also be used.

The capsule toner of the present invention thus obtained generally has the following characteristics:
The microcapsules have an outer shell with a thickness of 0.05 to 0.5 JL and a volume average particle size of 6 to 22p.

The capsule toner of the present invention further includes charge control.

Carbon black for the purpose of imparting fluidity and coloring.

Various dyes and pigments, hydrophobic colloidal silica, etc. can be added and mixed, and the effects of these additions can be stably exhibited. The appropriate amount of these additives to be added is about 0.1 to 5 parts by weight per 100 parts by weight of the capsule toner.

[Example] Specific embodiments of the present invention are shown below, but the present invention is not limited thereto.

Note that all parts used in the examples are parts by weight.

Production Example 1 A flask equipped with a stirrer and a thermometer and 9 dropping funnels was set on a hot plate, 100 parts of copper phthalocyanine was put into the flask, and stirred vigorously. Furthermore, while stirring strongly, heat the hot plate for 60 minutes.
10 parts of dimethyl silicone oil heated to 60°C was added dropwise through a dropping funnel. 5 after completion of dripping
Stirring was continued for a minute, and the mixture was cooled to room temperature to obtain treated product A.

Production Example 2 A treated product B was obtained in the same manner as Production Example 1 except that 25 parts of amine-modified silicone oil was used instead of 10 parts of dimethyl silicone oil.

Production Example 3 A treated product C was obtained in the same manner as Production Example 1, except that 100 parts of a magnetic material was used instead of copper phthalocyanine, and 5 parts of amino-modified silicone oil was used instead of 10 parts of dimethyl silicone oil.

Example 1 80 parts of paraffin wax as a core material, 20 parts of polyethylene wax, and 10 parts of treated product A were melt-mixed, granulated using a spray dryer, and further classified to have a volume average particle diameter of 12. A spherical core material of OIL was obtained. This core material was then separated from the organic phase using styrene-dimethylaminoethyl methacrylate (molar ratio 9
Encapsulated particles coated with 0/10) copolymer and having an outer shell with a thickness of 0.30 g were obtained.

Next, 1.0 g of hydrophobic silica was added to 100 g of the encapsulated particles.
g and further mixed with 90 g of iron powder carrier to prepare a developer, which was then transferred onto high-quality paper. Transfer the obtained transfer paper to 2
A book passed through a pressure fixing machine consisting of a pressure roller 1
Almost perfect fixing performance was exhibited at a linear pressure of 0 kg/Cm, and the image density was 1.5, forming a clear image without unevenness in density such as stains. At the same time, when the offset on the pressure roller was observed, no offset was observed, and no stains attributable to the offset were observed on the fixed image. Furthermore, when a durability test was conducted using 2,000 A4-sized originals, no offset was observed on the pressure roller, and the images obtained were clear and free from uneven shading such as stains.

Example 2 The same method as in Example 1 was repeated using treated product B instead of treated product A. When a test was conducted using the prepared developer, no offset was observed in either the initial stage or the durability test, and a clear image without any unevenness in density such as stains was obtained as in Example 1.

Example 3 A capsule toner was obtained in the same manner as in Example 1 except that 60 parts of treated product C was used instead of treated product A. An image reproduction test was conducted in the same manner as in Example 1 using this capsule toner as it was as a developer.

As a result, no offset was observed during the initial durability, and a clear image equivalent to that of Example 1 was obtained.

Comparative Example 1 Instead of using treated product A, a developer was prepared in the same manner as in Example 1 by using 10 parts of copper phthalocyanine pigment without treatment.

When one image was passed through a pressure roller using this developer, stains due to offset occurred on the pressure roller. When 100 more images were passed through the paper, the offset on the pressure roller became even worse, and stains on the fixing roller also appeared on the fixed images. Furthermore, stain-like unevenness in density appeared on the images from the initial stage through 100 sheets, which was thought to be caused by poor dispersion of the pigment.

[Effects of the Invention] When the toner of the present invention is used, clearer images can be obtained for a longer period of time, which is very useful.

Claims (1)

[Claims] 1. In a capsule toner comprising a core material containing a pressure fixing component and an outer shell covering at least a portion of the core material, silicone oil is contained in the core material. A pressure-fixable capsule toner characterized by containing pre-processed fine powder. 2. The pressure fixable capsule toner according to claim 1, wherein the amount of silicone oil to be processed is 1.0 to 30 parts by weight per 100 parts by weight of fine powder.