JPS6358359A - Carrier for developer - Google Patents

Abstract

PURPOSE:To improve surface staining resistance and to prevent decrease of an electric charge amount during operation by forming a layer containing a fluorine-containing compound on the surface of each core particle composed essentially of a resin and a magnetic powder to prepare a carrier for a developer. CONSTITUTION:The core particles are prepared by mixing the binder resin and fine magnetic particles as essential components, and a resin, a charge controller, a coupling agent, and the like, introducing them into a heat melting mixer, such as a kneader or Banbury mixer to knead the mixture, and after cooling, pulverizing and classifying it. The carrier for the developer is obtained by coating these core particles with a solution obtained by dissolving the fluorine-containing compound or together with a binder resin for the coating layer in a solvent not dissolving the binder resin of the core, then removing the solvent. As the binder resin, polystyreres, polyolefines, and the like are used, and as the fluorine-containing compound, tetrafluoroethylene, trifluoroethylene, and the like are used.

Description

Detailed Description of the Invention [Field of Industrial Application] 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, etc. This invention relates to a carrier as a constituent component, and more specifically to a magnetically dispersed carrier.

[Conventional technology]

In electrophotography, a photoconductive substance such as selenium is used as a photoreceptor, a spot-like latent image is formed by various means, and toner is applied to this latent image using a mountain brush development method. A method of attaching it and visualizing it is generally adopted.

In this development process, 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.

[Problem that the invention seeks to solve]

There are various properties required for carriers, but particularly important properties include appropriate charging properties, impact resistance, abrasion resistance,
Examples include developability and developer life.

Considering the above-mentioned required characteristics, the carriers that have been used in the past still have problems that need to be improved, and no carrier that fully satisfies them is known.

For example, conductive carriers such as iron oxide powder have excellent solid 9 developability, but have poor fine line reproducibility.
Additionally, it has drawbacks such as requiring the toner to contain a special charge control agent in order to extend its lifespan.On the other hand, coat-based insulating carriers are superior in terms of lifespan and reproducibility of fine lines, etc. It has the disadvantage of poor solid reproducibility. In order to improve these drawbacks, small particle size carriers in which magnetic fine particles are dispersed in a binder resin, so-called! A carrier for microtoning has been proposed and put into practical use, but there are problems such as adhesion of the carrier to the photoreceptor due to its small particle size, changes in charging at high and low humidity due to magnetic particles released on the surface, and surface treatment. Unfortunately, there are disadvantages such as the fact that it is impossible to radically extend the lifespan.

Accordingly, the main object of the present invention is to provide a new magnetic plan development carrier for use in electrophotography and electrostatic recording for the development of electrostatic a-images.

Other objects of the present invention are that the surface stain resistance is good, there is no decrease in the amount of charge during running, there is no early generation of capri, no internal contamination, and there is also a long developer life and high speed development. An object of the present invention is to provide an excellent carrier for magnetic brush development.

[Means for solving problems]

As a result of various studies and examinations to improve the drawbacks of the conventional carriers, the present inventors found that it is effective to provide a coating layer containing a fluorine-containing compound on the surface of a carrier core in which magnetic fine particles are dispersed. I was able to complete it.

That is, the present invention provides a developer carrier comprising a core containing a resin and magnetic powder as essential components, and a fluorine-containing compound-containing layer provided on the surface of the core.

In the carrier of the present invention, examples of the fluorine-containing compound used for the surface stone include the following.

That is, polymers containing fluorine in the main chain, such as homopolymerization of evatetrafluoroethylene, trifluoroethylene, vinylidene heptafluoride, monofluoroethylene, hexafluoropyrene, or the above-mentioned hepta-nomeric ethylene, fluoropylene, sotylene, chloride, etc. Examples include copolymers with copolymerizable unsaturated bond-containing monomers such as hinyl, hinyritene chloride, trifluoroethylene, and sono.

In addition, monomer polymers having fluorine in the side chain are also suitably used, and fluorinated alkyl acrylates or fluorinated alkyl methacrylates are mentioned as typical examples. Specifically, acrylic acid or methacrylic acid, 1.1-dihydro-70 loethyl, 1.1-9 hydrono-70 loprovir, 1.1-t human 90 per 70
lohexyl, 1,1-dihyto90 per 70 looctyl,
1,1-dihydroper 70 lodecyl, 1,1-', 'hir lono blue-two 70 lora'uril, 1,2,2-tetrahydroper 70 butyl, 1,1,2.2-f trahydroper 70 lohexyl , 1,1.2.2-tetrahydroperfluoro/thiA/, 1°1,2.2-tetrahydroper70 lodecyl, 1.1.2°2-tetrahydroper70 lolauryl, 1,1,2.2 -tetrahydronoseflorostearyl, 2,2,3.3-tetrafluoropropyl, 2.2.3.3.4.4-hexafluorobutyl, 1,1. ω-trihydroperfluorohexyl, 1,
1. ω-Trihydroper 70-octyl.

1,1.1.3.3.3-hexafluoro-2-chloropropyl, 3-no(-70lononyl-2-acetylpropyk, 3-half o o laf) IJ syl--acetylpropyl, N -ノ(-70hexylsulfonyl-N
-Methylaminoethyl, N-per70lohexylsulfonyl-N-methylaminoethyl N + /70looctylsulfonyl-N-methylaminoethyl, N-per70looctylsulfonyl-N-ethylaminoethyl, N- Per-70-octylsulfonyyw-N-methylaminoethyl, H-A-7.

Lobucylsulfonyl-N-methylaminoethyl, N-perfluorodecylsulfonyl-N-ethylaminoethyl,
H-, c-70 rhodecylsulfonyl N-, methylaminoethyl, N-par 70 lolauri AI sulfony h-'
Examples include ester compounds such as H-) thylaminoethyl, H-, fluoroncrylsulfonyl-N-dithylaminoethyl, and N-70 lolaurylsulfonyl-N-butylamino-ethyl.

As the component to be copolymerized with the fluorinated alkyl acrylate or fluorinated alkyl methacrylate, the following can be used.

Sodium, styrene, methylstyrene, dimethylstyrene,
Alkylstyrenes such as trimethylstyrene, ethylstyrene, diethylstyrene, triethylstyrene, flobylstyrene, butylstyrene, hexylstyrene, heptylstyrene, octylstyrene, fluorostyrene,
Styrenic monomers such as chlorostyrene bromostyrene, cyphlomostyrene, iodostyrene, halogenated styrene, nitrostyrene, acetylstyrene, methoxystyrene; acrylic acid, methacrylic acid, α-ethyl acrylic acid, crotonic acid, α- methyl crotonic acid,
α-ethylcrotonic acid, isocrotonic acid, tiglic acid,
Addition-polymerizable unsaturated aliphatic monocarboxylic acids such as ungellic acid; addition-polymerizable unsaturated aliphatic dicarboxylic acids such as maleic acid, fumaric acid, itaconic acid, citraconic acid, mesaconic acid, curtaconic acid, dihydromuconic acid; unsaturated carboxylic acids and alcohols, such as methyl alcohol, ethyl alcohol, flobyl alcohol, methyl alcohol, amyl alcohol, hexyl alcohol,
Alkyl alcohols such as heptyl alcohol, octyl alcohol, nonyl alcohol, dodecyl alcohol, tetradecyl alcohol, hexadecyl alcohol,
Some of these alkyl alcohols were alkoxylated. methoxyethyl alcohol, ethoxyethyl alcohol,
Aralkyl alcohols such as ethoxyethoxyethyl alcohol, methoxypropyl alcohol, ethoxypropyl alcohol, alkoxyalkyl alcohols, indyl alcohol, phenylethyl alcohol, phenylpropyl alcohol, allyl alcohol, crotonyl alcohol, alkenyl alcohols, etc., esterified products of Preferred examples include acrylic acid alkyl esters, methacrylic acid alkyl esters, heptamalic acid alkyl esters, maleic acid alkyl esters, etc.; amides and nitriles derived from the addition-polymerizable unsaturated carboxylic acids; ethylene, propylene, Aliphatic monoolefins such as butene and isobutylene; vinyl chloride, vinyl bromide, vinyl iodide, 1.2-)-tetraroethylene%1
, 2--J% lomoethylene, 1.2-9 iodo-1 ethylene, isopropenyl chloride, isopropenyl bromide, allyl chloride, allyl bromide, vinylidene chloride, vinyl heptadide, vinylidene fluoride, etc. Olefin; 1
, 3-butadiene, 1.3--! ntadiene, 1゜3-
Butadiene, 2,3-dimethyl-1,3-butadiene,
2. Conjugated diene aliphatic diolefins such as 4-hexadiene and 3-methyl-2,4-hexadiene; 2-vinylpyridine, 4-vinylpyridine, 2-vinyl-6-methylpyridine, 2-)'niru5 -methylpyridine, 4
-Butenylpyridine, 4-inchylpyridine, N-vinylbiyridine, 4-vinylbiyridine, 4-vinylpiperidine, N-hinyldihydropyridine, N-vinylpyrrole, 2-vinylpyrrole, N-vinylbilroline, N-
Vinylpyrrolidine, 2-vinylpyrrolidine, N-vinyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, N-
Examples include nitrogen-containing vinyl monomers such as vinyl carbazole. These can be used alone or in combination of two or more.

Furthermore, fluorinated epoxy resin, fluorinated polyester resin, fluorinated silicone resin, etc. can be used.

Next, fluorine-containing non-polymer compounds such as fluorine-containing alkoxysilane, fluorine-containing titanium acylate, fluorine-containing alkoxytitanium, fluorine-containing alkoxyzirconium, etc., fluorine-containing coupling agents, fluorine-containing surfactants, and Other fluorine atom-containing non-polymer compounds can be used.

In addition to the above-mentioned fluorine-containing compound, a thermoplastic resin generally used as a binder resin can also be used in the surface coating layer, if necessary. Specifically, styrenes such as styrene, chlorostyrene, and vinylstyrene; monoolefins such as ethylene, chlorostyrene, butylene, and imbutylene; vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate, and vinyl butyrate; methyl acrylate , ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, dodecyl methacrylate, etc.
Esters of methylene aliphatic monocarboxylic acids; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl methyl ether; homopolymers or copolymers of vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, vinyl isoproynyl ketone, etc. Typical binder resins for coating layers include polystyrene, styrene-alkyl acrylate copolymer, styrene-alkyl methacrylate copolymer, styrene-acrylonitrile copolymer, and styrene-butadiene copolymer. and styrene-maleic anhydride copolymer.

Further examples include polyester, polyurethane, epoxy resin, silicone resin, polyamide, modified rosin, norahin, and waxes.

Furthermore, halogen-containing polymers such as chlorinated olefins can be mentioned.

As the binder resin constituting the core of the carrier of the present invention, all general thermoplastic resins can be used, but specific examples include styrenes such as styrene, chlorostyrene, and vinylstyrene; ethylene, propylene, butylene, and isobutylene. vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate, vinyl butyrate; methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, phenyl acrylate, methyl methacrylate , esters of α-methylene aliphatic monocarboxylic acids such as ethyl methacrylate, butyl methacrylate, dodecyl methacrylate; vinyl methyl ether, vinyl ethyl ether, vinyl methyl ether, etc.; Examples include homopolymers or copolymers of vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, vinyl inoproynyl ketone, etc. Particularly representative binder resins include polystyrene, styrene- alkyl acrylate copolymer,
Styrene-alkyl methacrylate copolymer, styrene-
Examples include acrylonitrile copolymer, styrene-butadiene copolymer, L-styrene-maleic anhydride copolymer, polyethylene, and polypropylene.

Further examples include polyester, polyurethane, epoxy resin, silicone resin, polyamide, modified rosin, rough-in, and waxes.

In addition, the magnetic powder to be dispersed in the binder resin of the core can be any of the fine particles of ferromagnetic substances that are normally used. , various metal fine powders, etc.

The content of magnetic particles is usually 30% of the total amount of core components.
~95% by weight, preferably 45-90% by weight
The formulation gives good results.

In addition to binder resins and magnetic particles, resins, charge control agents, coupling agents, fillers, and other fine powders can be used as core components of carriers for charge control, improved dispersion, strength reinforcement, improved fluidity, and other purposes. It can also be added.

The core can be produced by various methods, such as pulverizing and classifying a mixture of binder resin and magnetic fine particles in a kneader, Banbury, etc., or spraying and cooling the mixture to solidify it. It can be manufactured by a method such as spray drying a binder solution in which magnetic fine particles are dispersed.

In addition, as a method for forming a fluorine-containing compound-containing layer on the surface of the core, a fluorine-containing compound or fluorine-containing layer is added to the core of a dispersed carrier containing the binder resin and magnetic fine particles as essential components in a solvent that does not dissolve the binder resin. Generally, a method is used in which a solution containing a fluorine compound and a binder resin for the layer is coated, and then the solvent is removed.

As coating equipment, it is possible to use fluidized beds, spray dryers, kneader coaters and other equipment.

The thickness of the coating layer of the carrier of the present invention is 0.01 μm to 5 μm.
It is appropriate that the thickness is preferably 0.1 to 1.0 μm.

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

The toner is not particularly limited and may be any chargeable toner that has a colorant dispersed in a binder resin and is commonly used in electrophotography.

〔Effect of the invention〕

The carrier for magnetic plan development of the present invention has a fluorine-containing compound-containing layer on the surface of the magnetic fine particle dispersed core, and since the magnetic fine particles are not released on the surface, it has poor environmental stability. There is little change in the amount of charge between summer and winter,
The drawbacks of the conventional calm dispersion type are greatly improved.

In addition, by adjusting the type and amount of fluorine-containing compounds,
It is possible to control the chargeability of Yarya.

Furthermore, since it is coated with a fluororesin layer that has a low surface energy, it is possible to prevent toner carrier contamination, extend the life of the toner, and stabilize chargeability.

〔Example〕

The present invention will be explained in more detail below using Examples and Comparative Examples. However, the present invention is not limited to these examples in any way. In addition, in the example below,
All parts represent parts by weight.

Example 1 Go parts of magnetic fine particles (EFT-1000, Toda Kogyo Co., Ltd.) and 20 parts of polyethylene (Mitsui Hiwax 400P, manufactured by Mitsui Petrochemicals Co., Ltd.) are heated and melted and kneaded in a pressurized Negoo. After sufficiently kneading, the mixture was cooled and solidified using a disk-type atomizer and classified to obtain a carrier core in which spherical magnetic particles were dispersed with an average particle diameter of 100 μm.

For 100 parts of this carrier core, styrene (St)-
Methyl methacrylate (MMA) copolymer (5t/MMA
=9V5 weight ratio) 5 parts of α, and 0.05 parts of a condensate of Per70 rononanoic acid and tetrabutoxidil; 10
% dissolved acetone solution using a fluidized bed coating apparatus to obtain a coated spherical magnetic particle dispersed carrier according to the present invention.

Comparative Example 1 A non-coated spherical magnetic material having the same composition as the carrier core of Example 1, kneaded, granulated, and classified in the same manner as in Example 1 except that the coating operation was discontinued, and having an average particle size of 100 μm. A particle dispersed carrier was obtained.

Example 2 70 parts of magnetic fine particles (EPT-1000) and 30 parts of polystyrene were melt-kneaded in a pressurized Neegoo, then crushed and classified using a turbo mill and a classifier to obtain an amorphous magnetic particle-dispersed carrier core with an average particle size of 100 μm. I got it. 100 parts of this carrier core was coated with a solution of 0.2 parts of par 7a lohexylethyl methacrylate in a 10TS fluorinated solvent (Gyflon Solvent S-3, Daikin Industries, Ltd. #i) using a fluidized bed coating device, and the present invention A coated amorphous magnetic fine particle dispersed carrier was obtained.

Comparative Example 2 The same formulation as the carrier core in Example 2 was used, except that the coating operation was stopped, and mixing, pulverization and classification were carried out in the same manner as in Example 2, and non--T type non-solids with an average particle size of 100 μm were obtained. A shaped magnetic particle dispersed carrier was obtained.

The carriers obtained in Examples 1 and 2 and Comparative Example 1.2 were evaluated as developers. The toner is FX with an average particle size of 11μ made of styrene-acrylic resin and carbon black.
-7770 copying machine toner (manufactured by Fuji Xerox Co., Ltd.) was mixed with a carrier at a concentration of 3% by weight to prepare a developer.

For these developers, photoreceptor speed 350 yes/
sec and developing magnetic roll (sleeve) speed 550 r
As t@7, the initial charge amount, frit 9 image density, background stain, fine line reproducibility, carrier adhesion to the photoconductor, charge amount after 100,000 sheets running, and solid image were measured using an evaluation inch machine. Density, background stain, and fine line reproducibility were evaluated, and tests were also conducted under high temperature (30° C., 80% R, H) and low humidity (10° C., 30% R, H) environmental conditions.

The results are shown in the following table), and the superiority of the carrier according to the present invention was revealed.

Claims (1)

[Claims] A developer carrier comprising a core containing resin and magnetic powder as essential components, and a fluorine-containing compound-containing layer provided on the surface of the core.