JPS5879254A - Developer - Google Patents

Abstract

PURPOSE:To stabilize triboelectric charging between a toner used as a developer for a static charge image and a developing sleeve by adding a binder resin contg. fine silica powder treated with a positive triboelectric charing substance to the toner. CONSTITUTION:Fine silica powder is dispersed in methanol and 2,6-diaminopyridine is added to carry out positive triboelectric charging treatment. After adding silicone resin varnish, they are agitated, freed of the solvent by evaporation, dried and pulverized to obtain treated silica. 30pts. of this positively chargeable treated silica are mixee with 100pts. toner. The toner is a powdered composition consisting of 50pts. magnetite, 2pts. nigrosine and 100pts. styrene copolymer. A negative static charge image is formed on a ZnO photoreceptor and developed with the resulting silica-contg. toner. The toner is uniformly attracted and a high quality image with no unevenness among the toner particles is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a round developer for developing electrostatic charges in electrophotography, electrostatic printing, electrostatic printing, and the like. More specifically, the present invention relates to a magnetic developer for electrophotography that is uniformly and strongly positively charged, visualizes a negative electrostatic charge position, and provides high quality in a direct or indirect electrophotographic development method.

Until now, as an electrophotographic method, there was an unregistered patent No. λ297,691.
Although a number of methods are known, such as No. (hereinafter referred to as toner), and if necessary, the toner image is transferred to a transfer material such as paper, and then fixed by heat, pressure, solvent vapor, etc. to obtain a copy. Furthermore, when a step of transferring toner is included, a step of removing residual toner on the photoreceptor is usually provided.

Development methods for visualizing electrical latent flaws using toner include, for example, the magnetic brush method described in U.S. Pat. No. 2,874,063, and the magnetic brush method described in U.S. Pat. Cascade development method and 2,221,7
Powder cloud method described in US Pat. No. 76, U.S. Pat.
, 909,258, a method using various insulating magnetic toners described in Japanese Patent Publication No. 41-9475, etc. are known. .

As toners applied to these developing methods, fine powders in which dyes and pigments are dispersed in natural or synthetic resins have conventionally been used. For example, particles obtained by dispersing a colorant in a binder resin such as polystyrene and pulverizing the particles to a size of about 1 to 301 μm are used as toner. As the magnetic toner, one containing magnetic particles such as magnetite is used.

Positive charge control agents used in such dry magnetic toners include, for example, amine compounds, quaternary ammonium compounds, and organic dyes, particularly basic dyes and their salts.
Common positive charge control agents include penzyldimethyl-hequinadecylantinium chloride, decyl-trimethylammonium chloride, nigeshin base, nigishin hydroxide chloride, safranin r, and crystal violet. In particular, nigrosine base and nigrosine tetralide are often used as positive charge control agents. These are usually added to a thermoplastic resin, heated and melted and dispersed, and then finely ground to adjust the particle size to a suitable size for use.

However, these dyes used as charge control agents have complex structures, inconsistent properties, and poor stability.They are susceptible to decomposition during thermal kneading, mechanical shock, friction, changes in temperature and humidity conditions, etc. It decomposes or changes in quality within a few seconds, resulting in a phenomenon in which charge controllability deteriorates. Therefore, when a toner containing these dyes as a charge control agent is used for development in a copying machine, the dye decomposes or changes in quality as the number of copies increases, causing deterioration of the toner during durability.

In addition, these dyes as charge control agents have a fatal drawback that it is extremely difficult to uniformly disperse them in thermoplastic resins, and that they cause differences in the amount of triboelectrification between toner particles obtained by rolling or crushing them. have. For this reason, various methods have been used to more uniformly disperse these dyes into resins. For example, basic nigrosine dyes are used to improve compatibility with thermoplastic resins.
It is used by forming salts with higher fatty acids, but often unreacted fatty acids or salt dispersion products are exposed on the toner surface and contaminate the developing sleeve etc., resulting in decreased fluidity of the toner, capri, #cutter, etc. This causes a decrease in concentration. Alternatively, in order to improve the dispersion of these dyes into the resin, a method is used in which the dye powder and the resin powder are mechanically pulverized and mixed beforehand, and then hot melt kneaded. The reality is that defectiveness cannot be avoided, and that sufficient uniformity of surface charge has not yet been obtained for practical use.

In addition, many of the positive charge controllable dyes are hydrophilic, and due to poor dispersion in these resins, the dyes are exposed on the toner surface when the dyes are melted and mixed and then crushed. When these toners are used under high humidity conditions, they have the disadvantage that good quality images cannot be obtained because the dyes are hydrophilic.

In this way, when conventional dyes with positive charge control properties are used in toner, charges are generated on the toner particle surface between toner particles or between toner and a toner carrier such as a sleeve. Correct variations in amount, develop fog,
Failures such as toner scattering may occur. In addition, these phenomena become particularly noticeable when a large number of copies are made,
The result is practically unsuitable for copying machines.

Also, under high temperature conditions, toner m1#! The transfer efficiency is significantly reduced, making it unusable. Furthermore, even at room temperature and humidity, when the toner is stored for a long time,
Due to the instability of the positive charge controlling dyes used, toner aggregation often occurs, rendering it unusable.

The present inventors have solved the various problems associated with conventional positively charged toners as described above, and have developed an electronic toner that is uniformly and strongly positively charged, visualizes a negative electrostatic charge image, and produces high-quality images. As a result of intensive research with the aim of providing a photographic appearance agent, it was found that if a developer contains silica fine powder treated with a positive triboelectric charge material, a negative electrostatic charge exhibiting various excellent properties can be produced. It has been found that a practical drug can be obtained. In particular, a developer containing fine silica powder treated with a substance selected from 1,4-vinylpyridine polymer, room temperature curing silicone resin, and aginoviridine compound has stable, constant, and uniform triboelectric charging properties. It has been found that the formation of nine.

That is, an object of the present invention is to ensure that the triboelectricity between toner particles or between the toner and the current sleeve is stable and uniform;
Kabu IJ) To provide a highly durable present agent that does not cause toner scattering or agglomeration.

Still another object is to provide a transfer agent that reproduces a stable image unaffected by changes in temperature and humidity, particularly a transfer agent that exhibits high transfer efficiency at high humidity.

In order to process the fine silica powder in the present invention, in order to process it most uniformly and efficiently, the positive triboelectric substance is dissolved in a suitable solvent, the fine silica powder is dispersed therein, the solvent is removed, and then, Drying and crushing methods can be applied. Solvent removal methods include evaporation, filtration, or spraying.
There is drying etc. First, when the positively triboelectrically charged substance is a polymer, fine silica powder may be granulated using it as a binder, and this will vary depending on the adsorption of the crushed material and its solubility in the solvent. , generally fine silica powder 10
It is preferable that 1 to 150 parts by weight of the positive triboelectric charging material is used per 0 parts by weight.

It is not clear how the positively triboelectrically charged substance is bound to the obtained treated silica fine powder, but it is thought that it is adsorbed internally or chemically.

The treated silica fine powder and toner may be mixed uniformly using a mixer such as a Henschel mixer, a V-type mixer, or a Turbler mixer. Although the mixing ratio varies depending on the triboelectricity, fluidity, etc. of the toner, it is generally desirable to mix 0.05 to 50 parts by weight of the treated silica fine powder to 100 parts by weight of the toner.

The fine silica powder used in the present invention may be produced by either a dry method or a wet method, or may be one that has been organically treated or hydrophobized with a silane coupling agent, silicone oil, etc. It is preferable to avoid fine silica powder that has negative triboelectric charging properties. In addition, the particle size is 1
4 with a secondary particle size of 2s or less is desirable.

As a binder resin for toner, monopolymers of styrene and its substituted products such as polystyrene, poly-P-chlorostyrene, and polyvinyltoluene, styrene-P-chlorostyrene copolymers, styrene-propylene copolymers, styrene/ −
Vinyl toluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-methyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, Styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-alpha-thalol methyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinylmethyl Ether copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl methyl keto/copolymer, styrene-butadiene copolymer,
Styrenic copolymers such as styrene-isoprene copolymer, styrene-acrylonitrile-inch/copolymer, styrene-maleic acid copolymer, styrene-Ileic acid ester copolymer, polymethyl methacrylate, polybutyl methacrylate, Polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, polyurethane, polyamide, epoxy resin, polyvinyl butyral, polyamide, polyacrylic acid resin, rosin, modified rosin, terpene resin, phenolic resin, aliphatic or alicyclic carbonized Hydrogen resin, aromatic petroleum resin, chlorinated paraffin, rough-in wax, etc. can be used alone or in combination.

As the coloring material used in the toner of the present invention, conventionally known carbon black, iron black, etc. can be used, and all the conventionally known dyes as positive charge control agents can be used in the toner. Various dyes include decyl ammonium chloride, decyl-trimethyl ammonium chloride, nigrosine base, nigrosine hydrochloride, safranin r and crystalno(iolet).

In the case of magnetic toner, IK) The magnetic material contained in Qi is a substance that is magnetized by being placed in a magnetic field, and powders of ferromagnetic metals such as iron, cobalt, and nickel are used.
Examples include alloys and compounds such as magnetite, hematite, and ferrite. The content of this magnetic powder is 15 to 70% by weight based on the weight of the toner.

The first characteristic of the Maruga electrostatic image developer constructed in this way is that there is no variation in triboelectric charging properties between toner particles or between toner sleeves, and the amount of charge is large, causing fogging, toner scattering, etc. can be prevented and durability can be improved.

Another feature of conventional positively charged pigments and dyes is their dispersibility. Although there is no selectivity between the binding beak used for LO and the combination with o*yit, there is a high selectivity between the treated silica fine powder used in the present invention and the resin. It has no selectivity, can be combined with any resin, and can be applied to a wide range of toner compositions. For example, it can be used for all heat fixing toners, pressure fixing toners, and capsule toners.

The basic configuration and features of the present invention have been described above, and the method of the present invention will be specifically explained below based on Examples. However, this does not limit the embodiments of the present invention in any way.

The above materials are melt-kneaded, cooled, pulverized, and classified to 5 to 25
It was made into μ toner.

Further, a negative electrostatic image was formed on a zinc oxide photoreceptor by a conventionally known electrophotographic method, and an attempt was made to print the image with the above toner, but only a faint image appeared.

Therefore, 200 g of fine silica powder (Japan Silica G-150K silane-coupled with trimethylmethoxysilane) was added to silicone resin/varnish (Toshi 8R2410 resin) 11, and after stirring, the solvent was evaporated and transferred. The treated silica was crushed and sieved using a 200 mesh sieve to obtain treated silica.

When 30 parts of this treated silica was mixed with 100 parts of toner to develop a negative electrostatic image on the zinc oxide photoreceptor, a high quality image with high image density was obtained. This Ii
Even after making 10,000 copies, it did not deteriorate.

[Example 2] 4-vinylpyridine polymer average molecular weight 3oo, o-o.

20g for 1! The same procedure as in Example 1 was carried out, except that fine silica powder (Japan Silica G-150K) 20011 was added to the solution dissolved in methanol, and the same results were obtained.

[Example 3] 25 g of 4-aminopyridine (manufactured by Koei Chemical Co., Ltd.) was added to 500 m
100 g of fine silica powder (B-5o manufactured by Tokuyama Ichida) was added to a solution dissolved in methanol, and the same procedure as in Example 1 was carried out except for 9, and the same O result was obtained.

[Example 4] 500 g of 2.6-diamitubiridine manufactured by Kogaku Kagaku Co., Ltd.
Example 1 was carried out in the same manner as in Example 1, except that 100 g of fine silica powder (Shionogi & Co., Ltd., Vol. 1, No. 1120) was added to a solution dissolved in methanol, and the same results were obtained.

Sender Canon Co., Ltd.

Claims (1)

[Claims] A developer characterized in that it is treated with a positively triboelectrically charged substance and contains nine silica fine powders.