JP2569521B2 - Carrier for developer - Google Patents

Description

The present invention relates to a two-component developer for developing an electrostatic latent image or a magnetic latent image in electrophotography, electrostatic recording, electrostatic printing, and the like. The present invention relates to a carrier which is a constituent component, and more particularly, to a carrier in which a magnetic substance is dispersed.

[Prior Art] In electrophotography, a photoconductive substance such as selenium is used as a photoreceptor, an electric latent image is formed by various means, and the latent image is formed by a magnetic brush developing method or the like. A method of visualizing an image by attaching toner is generally adopted.

In this development step, carrier particles called carriers are used to impart an appropriate amount of positive or negative electricity to the toner. Various types of carriers have been developed and put into practical use.

[Problems to be Solved by the Invention] There are various characteristics required for a carrier, and particularly important characteristics include appropriate chargeability, impact resistance, abrasion resistance, and the like.
Developability, developer life, and the like can be given.

In view of the above-mentioned required characteristics, conventionally used carriers still have problems to be improved, and no satisfactory carrier has been known. For example, conductive carriers such as iron oxide powder are excellent in solid developability, but inferior in fine line reproducibility, and require a special charge control agent to be included in the toner to extend the life. On the other hand, the coated insulating carrier is excellent in life, reproducibility of fine wires, etc., but is inferior in solid reproducibility. For the purpose of remedying these drawbacks, small particle size carriers in which magnetic fine particles are dispersed in a binder resin, so-called microtoning carriers, have been proposed and put into practical use. It has the disadvantage of adhering to the body.
Although this development can be prevented by increasing the particle size of the carrier, the increase in the particle size of the carrier lowers the chargeability, resulting in problems such as fogging and contamination in the machine.

Accordingly, it is a primary object of the present invention to provide a novel carrier for a magnetic brush developer used for developing an electrostatic latent image in electrophotography and electrostatic recording.

Another object of the present invention is to provide a carrier for a magnetic brush developer which prevents a decrease in the charge amount, and as a result, does not cause early fog and contamination inside the machine, and further has excellent developer life and high-speed developability. Is to do.

Means for Solving the Problems The present invention achieves the above and other objects by spraying a resin material containing a coexisting polymer of a fluorine-containing monomer and a polyolefin capable of radical polymerization and a carrier material melt containing magnetic fine particles as essential components. This is achieved by the carrier obtained by cooling.

In the present invention, the fluorine-containing monomer to be co-polymerized with the polyolefin may be a general radical-polymerizable fluorine-containing compound, or any combination of the fluorine-containing compound and a general radical-polymerizable monomer copolymerizable with the fluorine-containing compound. .

 Specific examples of co-polymerizable monomers are shown below.

First, examples of the fluorine-based monomer used in the present invention include the following.

That is, monomers containing fluorine in the main chain, such as tetrafluoroethylene, trifluoroethylene, vinylidene fluoride, monofluoroethylene, hexafluoropropylene, and the like, and these monomers and ethylene, propylene, butylene, and vinyl chloride. , Vinylidene chloride, trifluoroethylene, and other copolymerizable unsaturated bond-containing monomers.

Further, a compound containing fluorine in the side chain is also preferable, and particularly, fluorinated alkyl acrylate and fluorinated alkyl methacrylate are listed as typical compounds.Specifically, acrylic acid or methacrylic acid, Dihydroperfluoroethyl, 1,1-dihydroperfluoropropyl, 1,1-dihydroperfluorohexyl, 1,1-dihydroperfluorooctyl, 1,1-dihydroperfluorodecyl, 1,1-dihydroperfluorolauryl, 1,1,2,2-tetrahydroperfluorobutyl, 1,1,2,2-tetrahydroperfluorohexyl, 1,1,2,2-tetrahydroperfluorooctyl, 1,1,2,2-tetrahydroperfluorobutyl Decyl,
1,1,2,2-tetrahydroperfluorolauryl, 1,1,2,2-
Tetrahydroperfluorostearyl, 2,2,3,3-tetrafluoropropyl, 2,2,3,3,4,4-hexafluorobutyl,
1,1, ω-trihydroperfluorohexyl, 1,1, ω-trihydroperfluorooctyl, 1,1,1,3,3,3-hexafluoro-2-chloropropyl, 3-perfluorononyl-2 −
Acetylpropyl, 3-perfluorolauryl-2-acetylpropyl, N-perfluorohexylsulfonyl-N
-Methylaminoethyl, N-perfluorohexylsulfonyl-N-butylaminoethyl, N-perfluorooctylsulfonyl-N-methylaminoethyl, N-perfluorooctylsulfonyl-N-methylaminoethyl, N-
Perfluorooctylsulfonyl-N-butylaminoethyl, N-perfluorodecylsulfonyl-N-methylaminoethyl, N-perfluorodecylsulfonyl-N-ethylaminoethyl, N-perfluorodecylsulfonyl-N
Ester compounds such as -butylaminoethyl, N-perfluorolaurylsulfonyl-N-methylaminoethyl, N-perfluorolaurylsulfonyl-N-ethylaminoethyl, N-perfluorolaurylsulfonyl-N-butylaminoethyl and the like. Can be

The following can be used as a component to be copolymerized with the fluorinated alkyl acrylate or the fluorinated alkyl methacrylate.

That is, styrene, methyl styrene, dimethyl styrene, trimethyl styrene, ethyl styrene, diethyl styrene, triethyl styrene, propyl styrene, butyl styrene, hexyl styrene, heptyl styrene,
Alkylstyrenes such as octylstyrene, halogenated styrenes such as fluorostyrene, chlorostyrene, bromostyrene, dibromostyrene, iodostyrene, and styrene-based monomers such as nitrostyrene, acetylstyrene and methoxystyrene; acrylic acid, methacrylic acid, α- Ethyl acrylic acid, crotonic acid, α-methyl crotonic acid, α-ethyl crotonic acid, isocrotonic acid, tiglic acid, addition-polymerizable unsaturated aliphatic monocarboxylic acids such as ungeric acid, maleic acid, fumaric acid, itaconic acid,
Citraconic acid, mesaconic acid, geltaconic acid, addition-polymerizable unsaturated aliphatic dicarboxylic acids such as dihydromuconic acid; the above-mentioned addition-polymerizable unsaturated carboxylic acids and alcohols, for example, methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, amyl alcohol; Hexyl alcohol, heptyl alcohol, octyl alcohol,
Alkyl alcohols such as nonyl alcohol, dodecyl alcohol, tetradecyl alcohol, and hexadecyl alcohol; alkoxys such as methoxyethyl alcohol, ethoxyethyl alcohol, ethoxymethyl alcohol, methoxypropyl alcohol, and ethoxypropyl alcohol obtained by partially alkoxylating these alkyl alcohols Alkyl alcohols such as benzyl alcohol, phenylethyl alcohol, and phenylpropyl alcohol, and alkenyl alcohols such as allyl alcohol and crotonyl alcohol, and the like, especially alkyl acrylates, alkyl methacrylates, and alkyl fumarates Esters and alkyl maleates are preferred. Amides and nitriles derived from the addition-polymerizable unsaturated carboxylic acids; aliphatic monoolefins such as ethylene, propylene, butene, and isobutylene; vinyl chloride, vinyl bromide;
Vinyl iodide, 1,2-dichloroethylene, 1,2-dibromoethylene, 1,2-diiodoethylene, isopropenyl chloride, isopropenyl bromide, allyl chloride, allyl bromide, vinylidene chloride, vinyl fluoride, fluoride Halogenated aliphatic olefins such as vinylidene; 1,3-butadiene, 1,3-
Pentadiene, 1,3-butadiene, 2,3-dimethyl-1,3
-Butadiene, 2,4-hexadiene, 3-methyl-2,4-
Conjugated diene-based aliphatic diolefins such as hexadiene; 2
-Vinylpyridine, 4-vinylpyridine, 2-vinyl-
6-methylpyridine, 2-vinyl-5-methylpyridine, 4-butenylpyridine, 4-pentylpyridine, N
-Vinylpiperidine, 4-vinylpiperidine, 4-vinylpiperidine, N-vinyldihydropyridine, N-vinylpyrrole, 2-vinylpyrrole, N-vinylpyrroline, N-vinylpyrrolidine, 2-vinylpyrrolidine, N
And nitrogen-containing vinyl monomers such as -vinyl-2-pyrrolidone, N-vinyl-2-piperidone, and N-vinylcarbazole. These can be used alone or in combination of two or more.

In the present invention, all polyolefins such as polyethylene, polypropylene, polybutylene and polyisobutylene can be used as the polyolefin.

As the binder resin for the carrier used in the present invention, any of the general thermoplastic resin groups can be used. Specifically, styrenes such as styrene, chlorostyrene, and vinylstyrene: ethylene, propylene, butylene And monoolefins such as isobutylene: vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate and vinyl butyrate: methyl acrylate, ethyl acrylate,
Esters of α-methylene aliphatic monocarboxylic acids such as butyl acrylate, dodecyl acrylate, octyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, dodecyl methacrylate: vinyl methyl ether, vinyl ethyl ether,
Vinyl ethers such as vinyl butyl ether: homopolymers or copolymers such as vinyl methyl ketone, vinyl hexyl ketone, and vinyl ketone such as vinyl isopropenyl ketone can be exemplified. Particularly typical binder resins include polystyrene and styrene. -Alkyl acrylate copolymer, styrene-alkyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyethylene, and polypropylene.

In addition, polyester, polyurethane, epoxy resin,
Silicone resin, polyamide, modified rosin, paraffin,
Waxes can be mentioned.

In the present invention, the amount of the co-polymer of the fluorine-containing monomer and the polyolefin contained in the binder resin is from 0.01% by weight to 20% by weight based on the total amount of the components of the carrier.

In the carrier of the present invention, the magnetic fine particles used by being dispersed in a binder resin may be all commonly used ferromagnetic fine particles, specifically, triiron tetroxide,
γ-iron sesquioxide, various ferrite powders, chromium oxide, various metal fine powders, and the like.

The content of the magnetic particles is usually about 30 to 95% by weight, preferably 45 to 90% by weight, based on the total amount of the binder resin, and gives good results.

The carrier of the present invention includes a resin, a charge controlling agent, and a coupling agent for controlling the charge, improving the dispersion, reinforcing the strength, improving the fluidity, and other purposes, in addition to the binder resin, the coexisting polymer of the magnetic fine particle fluorine-containing monomer and the polyolefin. , Fillers and other fine powders may be added to the inside of the carrier.

 Next, a method for manufacturing the carrier will be described.

The carrier of the present invention contains the binder resin, a coexisting polymer of a fluorine-containing monomer and a polyolefin, and magnetic fine particles as essential components, and heat-melts and mixes these components with other components to form a relatively low-temperature air without solidifying the mixture. It is manufactured by cooling and solidifying with a flow.

More specifically, the manufacturing apparatus includes a heating / melting / mixing device and a kneaded material viscosity adjusting tank as pretreatment equipment, and further includes a pump for conveying the kneaded material to a spraying device and a cooling tower for cooling and solidifying the sprayed kneaded material. ing.

Kneaders, roll mills,
Banbury, sand mill, attritor, Henschel mixer, etc. can be used. As a spraying device, a nozzle type or a disk type is relatively suitable for obtaining a carrier having a small particle size, but is not limited thereto. Not something.

The average particle diameter of the carrier of the present invention is 20 to 40 from the balance between the life of the developer, the adhesion of the carrier to the photoreceptor, and the image quality.
It is suitable that the thickness is 0 μm, more preferably 30 to 200 μm.

The carrier of the present invention thus obtained is mixed with a toner and used as a magnetic brush developer for developing an electrostatic latent image.

As the toner, any chargeable toner having a colorant dispersed in a binder resin and used in normal electrophotography can be used, and is not particularly limited.

[Effects of the Invention] The carrier for magnetic brush development of the present invention spray-cools a carrier material melt containing a binder resin containing a coexisting polymer of a fluorine-containing monomer capable of radical polymerization and a polyolefin and a magnetic powder as essential components. Thus, the following effects are achieved.

Since the fluorine-containing polymer has a very low surface energy, the spray-cooled carrier material melted by heating transfers the fluorine-containing polymer to the surface and spontaneous surface deposition occurs.

A part of the precipitated fluorine-containing polymer forms a graft polymer in which the fluorine-containing monomer is polymerized to the radical of the polyolefin, which is generated by extracting hydrogen by the radical when the radical polymerization of the fluorine-containing monomer is caused by coexistence of the polyolefin. As a result, a stable fluorine-containing layer is formed on the carrier surface in one step.

Therefore, the surface energy of the carrier can be reduced by adding a small amount of the fluorine-containing polymer, and the life of the carrier can be prolonged by reducing the impact of the toner on the carrier.

By adjusting the type and amount of the fluoropolymer, the chargeability of the carrier can be controlled.

Further, since the affinity of the surface of the carrier particles with the fluorine-based material is improved, when the carrier particles are coated with the fluorine-based material, peeling of the coating layer is prevented.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples. However, the invention is not limited in any way by these examples. In the following examples, parts represent parts by weight.

Example 1 Magnetic fine particles (EPT-1000, manufactured by Toda Kogyo KK) 80 parts Polyester (condensation product of hydrogenated bisphenol A and butanediol with fumaric acid) 19.5 parts Trifluoroethylene and polyethylene (Mitsui High Wax)
0.5 part of a 2: 8 coexisting polymer with 400P (manufactured by Mitsui Petrochemical Co., Ltd.) was heated and melt-kneaded in a pressure kneader. After that, the viscosity was adjusted to 600 CP in a viscosity adjusting tank, spray-cooled by a disk-type spraying device, solidified, then classified, and the average particle size according to the present invention.
A 100 μm spherical magnetic particle dispersed carrier was obtained.

Comparative Example 1 80 parts of magnetic fine particles (EPT1000, manufactured by Toda Kogyo KK) 80 parts polyester (hydrogenated bisphenol A and condensate of butanediol and fumaric acid) 20 parts were sprayed, cooled and solidified in the same manner as in Example 1. And classified to obtain a spherical magnetic particle-dispersed carrier having an average particle diameter of 100 μm.

Example 2 Magnetic fine particles (EPT1000, manufactured by Toda Kogyo) 80 parts Polyethylene (Mitsui High Wax 400P, manufactured by Mitsui Petrochemical) 19.8 parts Perfluorohexylethyl methacrylate and polyethylene (Mitsui High Wax 400P, manufactured by Mitsui Petrochemical) 5: 5
0.2 parts of the coexisting polymer is heated and melt-kneaded in a pressure kneader, then sprayed, cooled and solidified using a disk type spraying device, and then classified, and the spherical magnetic particle-dispersed carrier according to the present invention having an average particle size of 100 μm is obtained. I got

Example 3 A 100% solution of a fluorine-based solvent (Diflon Solvent S-3, manufactured by Daikin Industries, Ltd.) containing 0.2 parts of perfluorohexylethyl methacrylate polymer was kneaded with 100 parts of the carrier particles obtained in Example 2. Coating was performed using a coater to obtain a coated spherical magnetic particle-dispersed carrier according to the present invention.

Comparative Example 2 80 parts of magnetic fine particles (EPT1000, manufactured by Toda Kogyo Co., Ltd.) 80 parts of polyethylene (Mitsui High Wax 400P, manufactured by Mitsui Petrochemical Co., Ltd.) were sprayed, cooled, solidified and classified in the same manner as in Example 2,
A spherical magnetic particle-dispersed carrier core having an average particle diameter of 100 μm was obtained.

This core was coated with 0.2 part of perfluorohexylethyl methacrylate polymer in the same manner as in Example 3 to obtain a coated spherical magnetic particle-dispersed carrier.

The carriers obtained in Examples 1, 2, and 3 and Comparative Examples 1 and 2 were evaluated as developers. The toner has an average particle size of 11μ composed of styrene-acrylic resin and carbon black.
Using a toner for FX-7770 copier (manufactured by Fuji Xerox Co., Ltd.), it was mixed with a carrier at a concentration of 3% by weight to prepare a developer.

For these developers, the photoconductor speed was 350 mm / sec and the developing magnetic roll (sleeve) speed was 550 mm / sec, and the initial charge amount, solid image density, background stain, fine line reproducibility, and fine line reproducibility on the bench machine for evaluation. The carrier adhesion, the charge amount during running 100,000 sheets, the solid image density, the background stain, the fine line reproducibility, etc. were evaluated, and the high humidity (30 ° C, 80% RH) and low humidity (10 ° C, 30% RH) Tested under environmental conditions. The results are as shown in the following table, and the superiority of the carrier according to the present invention became apparent.

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Yasuo Matsumura 1600 Takematsu, Minami Ashigara-shi, Fuji Xerox Co., Ltd. JP-A-56-167150 (JP, A) JP-A-60-202451 (JP, A) JP-A-58-200245 (JP, A) JP-A-55-67754 (JP, A) JP-A-60-241057 (JP, A) JP-A-58-200244 (JP, A)

Claims (1)

(57) [Claims] A carrier for a developer obtained by spray-cooling a carrier material melt containing a binder resin containing a coexisting polymer of a fluorine-containing monomer capable of radical polymerization and a polyolefin and a magnetic powder as essential components.