JPH0820775B2 - 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. More specifically, the present invention relates to a carrier that is a constituent component, and more specifically to a magnetic substance-dispersed carrier.

[Conventional technology]

In electrophotography, a photoconductive substance such as selenium is used as a photoreceptor, an electric latent image is formed by various means, and toner is attached to the latent image using a magnetic brush development method or the like. A method of visualizing 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 the carrier, but particularly important characteristics are appropriate chargeability, impact resistance, abrasion resistance,
Developability, developer life, etc. can be mentioned.

In view of the above-mentioned required characteristics, the 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 coat-based insulating carrier is excellent in the life and the reproducibility of fine wires, but has the disadvantage of inferior solid reproducibility. A small particle size carrier in which magnetic fine particles are dispersed in an adhesive resin, a so-called microtoning carrier, has been proposed and put to practical use for the purpose of improving these drawbacks. It has the disadvantage of adhering to This phenomenon can be prevented by increasing the particle size of the carrier, but the charging property decreases due to the increase in the particle size of the carrier, and as a result, problems such as fogging and contamination inside the machine occur. .

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

Another object of the present invention is to prevent a decrease in the amount of charge with a large particle size carrier that does not adhere to the photosensitive member, resulting in the early occurrence of fog and no in-machine contamination, and further the developer life, An object of the present invention is to provide a carrier for magnetic brush development which is excellent in high-speed developability.

[Means for solving problems]

The present invention is a binder resin containing 0.01 to 50 parts by weight of a fluorine-containing compound, an average particle size of 50μ dispersed magnetic fine particles
It provides a carrier for a developer of m or more.

In the carrier of the present invention, a fluorine-containing compound is used as an additive for improving the charging property.

Examples of fluorine-containing compounds include the following.

That is, a polymer containing fluorine in the main chain, for example, tetrafluoroethylene, trifluoroethylene, vinylidene fluoride, monofluoroethylene, a homopolymer such as hexafluoropropylene or the above monomers and ethylene, propylene, butylene, vinyl chloride. , Vinylidene chloride, trifluoroethylene, and copolymers with other copolymerizable unsaturated bond-containing monomers.

Further, a polymer of a monomer having fluorine in the side chain is also preferably used. Particularly, a fluorinated alkyl acrylate or a fluorinated alkyl methacrylate is mentioned as a typical monomer, and specifically acrylic acid or methacrylic acid is used. , 1,1-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-tetrahydroperfluorodecyl, 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, 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-ethylaminoethyl, N-perfluorooctylsulfonyl-N
-Butylaminoethyl, N-perfluorodecylsulfonyl-N-methylaminoethyl, N-perfluorodecylsulfonyl-N-ethylaminoethyl, N-perfluorodecylsulfonyl-N-butylaminoethyl, N-perfluorolaurylsulfonyl -N-methylaminoethyl, N
-Ester compounds such as perfluorolaurylsulfonyl-N-ethylaminoethyl N-perfluorolaurylsulfonyl-N-butylaminoethyl and the like can be mentioned.

The following components can be used as the component 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, alkyl styrene such as octyl styrene, fluorostyrene, chlorostyrene bromostyrene, dibromo Halogenated styrenes such as styrene and iodostyrene, styrene-based monomers such as nitrostyrene, acetylstyrene and methoxystyrene; acrylic acid, methacrylic acid,
Addition-polymerizable unsaturated aliphatic monocarboxylic acid such as α-ethyl acrylic acid, crotonic acid, α-methyl crotonic acid, α-ethyl crotonic acid, isocrotonic acid, tiglic acid, ungeric acid, maleic acid, fumaric acid, itaconic acid , Addition-polymerizable unsaturated aliphatic dicarboxylic acids such as citraconic acid, mesaconic acid, glutaconic acid and dihydromuconic acid; the addition-polymerizable unsaturated carboxylic acids and alcohols such as methyl alcohol, ethyl alcohol, propyl alcohol,
Butyl alcohol, amyl alcohol, hexyl alcohol, heptyl alcohol, octyl alcohol, nonyl alcohol, dodecyl alcohol, tetradecyl alcohol, hexadecyl alcohol, and other alkyl alcohols, methoxyethyl alcohol, ethoxyethyl alcohol partially alkoxylated from these alkyl alcohols. , Alkoxyalkyl alcohols such as ethoxyethoxyethyl alcohol, methoxypropyl alcohol, ethoxypropyl alcohol, benzyl alcohol,
Esters with aralkyl alcohols such as phenylethyl alcohol and phenylpropyl alcohol, alkenyl alcohols such as allyl alcohol and crotonyl alcohol, especially alkyl acrylates, methacrylic acid alkyl esters, fumaric acid alkyl esters, maleic acid alkyls Esters and the like are preferable examples; amides and nitriles derived from the addition-polymerizable unsaturated carboxylic acid; ethylene, propylene, butene,
Aliphatic monoolefin such as isobutylene; vinyl chloride, vinyl bromide, vinyl iodide, 1,2-dichloroethylene, 1,2-dibromoethylene, 1,2-diiodoethylene,
Halogenated aliphatic olefins such as isopropenyl chloride, isopropenyl bromide, allyl chloride, allyl bromide, vinylidene chloride, vinyl fluoride, vinylidene fluoride; 1,3-
Butadiene, 1,3-pentadiene, 2,3-dimethyl-1,3
-Butadiene, 2,4-hexadiene, 3-methyl-2,4-
Conjugated diene-based aliphatic diolephins such as hexadiene; 2
-Vinyl pyridine, 4-vinyl pyridine, 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 alone or 2
Combinations of more than one species can be used.

Further, fluorine-containing epoxy resin, fluorine-containing polyester resin, fluorine-containing silicon resin, etc. can be used.

Next, a non-polymer compound containing fluorine, such as a fluorine atom-containing alkoxysilane, a fluorine atom-containing titanium acylate, a fluorine atom-containing alkoxytitanium, a fluorine atom-containing alkoxyzirconium-containing coupling agent, and a fluorine-containing coupling agent. Elementary surfactants and other fluorine atom-containing non-polymer compounds can be used.

As the binder resin for the carrier of the present invention, all of the general thermoplastic resin groups can be used, but specifically, styrenes such as styrene, chlorostyrene, vinylstyrene; ethylene, propylene, butylene, isobutylene, etc. Monoolefins; vinyl acetate, vinyl propionate,
Vinyl esters such as vinyl benzoate and vinyl acetate; methyl acrylate, ethyl acrylate, butyl acrylate,
Dodecyl acrylate, octyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate,
Α-Methylene aliphatic monocarboxylic acid esters such as butyl methacrylate and dodecyl methacrylate; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl butyl ether; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and vinyl isopropenyl ketone. Examples of the binder resin include polystyrene, styrene-alkyl acrylate copolymer, styrene-alkyl methacrylate copolymer, and styrene-acrylonitrile copolymer. Examples thereof include polymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyethylene and polypropylene.

Further, polyester, polyurethane, epoxy resin, silicone resin, polyamide, modified rosin, paraffin, wax can be mentioned.

As the magnetic fine particles to be dispersed in the binder resin in the carrier of the present invention, it is possible to use all of the fine particles of a ferromagnetic substance that are usually used, but specifically, ferric tetroxide, γ-iron sesquioxide, Various ferrite powder, chromium oxide,
Examples include various metal fine powders.

The proportion of each component constituting the carrier of the present invention, for the fluorine-containing compound as a chargeability improver, varies depending on the type of the compound, but is generally 0.01 to 50% by weight with respect to the total amount of the binder resin. , Preferably 0.1 to 20% by weight,
Also, the content of magnetic particles is usually relative to the total amount of carriers.
About 30-95% by weight, desirably 45-90% by weight gives good results.

In the carrier of the present invention, in addition to the above-mentioned constituents, charge control, dispersion improvement, strength reinforcement, fluidity improvement and other purposes,
Resins, charge control agents, coupling agents, fillers and other fine powders can be added.

The carrier particles of the present invention can be used as carrier particles as they are, but the surface can be subjected to surface treatment or coating treatment with a resin, a coupling agent, a surfactant, a charge control agent, a fine powder or the like.

The carrier of the present invention can be manufactured by various methods. For example, a method in which a binder resin, a fluorine-containing compound, magnetic fine particles are kneaded by a heating and melting mixing device such as a kneader or Banbury, and pulverized or classified, or
It is produced by a method of spraying, cooling and solidifying the kneaded product.

The average particle size of the carrier of the present invention is 50 μm to 400 μm, preferably 50 to 100 μm, in view of the balance between the adhesion of the carrier to the photosensitive member and the image quality.

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

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

〔The invention's effect〕

The magnetic brush developing carrier of the present invention comprises magnetic particles dispersed in a binder resin containing 0.01 to 50 parts by weight of a fluorine-containing compound, and has a large particle size of 50 μm or more. The following effects can be obtained.

First, in order to remove almost all of the fine particles by increasing the particle size, it is possible to greatly reduce the adhesion of the carrier to the photoconductor as compared with the conventional magnetic particle-dispersed carrier having a small particle size.

Also, by adjusting the type and amount of the fluorine-containing compound, the chargeability of the carrier can be controlled, and appropriate chargeability can be imparted despite the increase in particle size. Further, as an effect of adding the fluorine-containing compound, the surface energy of the carrier is lowered, the carrier contamination of the toner can be prevented, the life can be extended, and the charging property can be stabilized.

〔Example〕

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 Co., Ltd.) 70 parts, styrene (St) -n-butyl methacrylate (n-
24 parts of BMA) copolymer (St / n-BMA = 85/15) and 6 parts of tetrafluoroethylene resin (Lubron L-2, manufactured by Daikin Industries, Ltd.) are melt-kneaded with a pressure kneader, then turbo milled and classified. The powder was pulverized and classified by a machine to obtain an amorphous magnetic powder-dispersed carrier having an average particle diameter of 100 μm.

Comparative Example 1 70 parts of magnetic fine particles (EPT-1000) and 30 parts of styrene-n-butyl methacrylate (St / n-BMA = 85/15) were kneaded, ground and classified in the same manner as in Example 1 to obtain average particles. A magnetic powder dispersion type carrier having a diameter of 100 μm was obtained.

Example 2 60 parts of magnetic fine particles (EPT-1000), 25 parts of polyethylene (Mitsui Hiwax 400P, manufactured by Mitsui Petrochemical Co., Ltd.), and 15 parts of trifluoroethylene-vinyl chloride copolymer (FPC461, manufactured by Fear Earthton Co., Ltd.) were pressed. The mixture was heated, melted and kneaded with a kneader. After sufficiently kneading, the mixture was cooled and solidified by using a disc type spraying device, and then classified to obtain a spherical magnetic powder dispersion type carrier having an average particle diameter of 100 μm.

Comparative Example 2 60 parts of magnetic fine particles (EPT-1000) and 40 parts of polyethylene (Mitsui Hiwax 400P) were sprayed in the same manner as in Example 2,
After cooling and solidification, classification was carried out to obtain a spherical magnetic powder dispersion type carrier having an average particle size of 100 μm.

The carriers obtained in Examples 1 and 2 and Comparative Examples 1 and 2 were evaluated as developers. As toner, FX-7770 copier toner (manufactured by Fuji Xerox Co., Ltd.) having an average particle size of 11 μm and made of styrene-acrylic resin and carbon black was used, and the density was 3
A developer was prepared by mixing the carrier with the carrier at a ratio of wt%.

For these developers, with the photoconductor speed of 350 mm / sec and the developing magnetic roll (sleeve) speed of 550 mm / sec, the initial charge amount on the evaluation bench machine, solid image density, background stain, reproducibility of fine lines, and photoconductor Carrier adhesion, charge amount during 100,000 sheets running, solid image density, background stain, and fine line reproducibility were evaluated. High humidity (30 ℃, 80% RH) and low humidity (10 ℃, 30% RH) ) We also 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 clear.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Chiaki Suzuki 1600 Takematsu, Minamiashigara-shi, Kanagawa Fuji Xerox Co., Ltd. Takematsu Plant (72) Inventor Takayoshi Aoki 1600 Takematsu, Minamiashigara-shi, Kanagawa Fuji Xerox Co., Ltd. Takematsu Business In-house (56) Reference JP 54-68246 (JP, A) JP 61-15156 (JP, A) JP 58-21750 (JP, A) JP 59-90860 (JP, A)

Claims (1)

[Claims] 1. An average particle size of 50 .mu.m obtained by dispersing magnetic fine particles in a binder resin containing 0.01 to 50 parts by weight of a fluorine-containing compound.
m or more developer carrier.