JP3101041B2 - Carrier for electrophotographic toner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic toner carrier (electrophotographic toner conveying member) for developing an electrostatic latent image such as electrophotography and electrostatic recording.

[0002]

2. Description of the Related Art Dry-type electrophotographic developing methods include a so-called two-component developing method comprising a mixture of carrier particles and toner particles, and a one-component developing method comprising only toner particles.

The two-component dry developer is charged by electric force generated by friction between relatively large carrier particles and fine toner particles. Attracts the toner particles to the latent image in the direction of the latent image due to the electric field generated by the toner, and overcomes the bonding force between the toner particles and the carrier particles, so that the toner particles are attracted and adhered on the electrostatic latent image and the electrostatic latent image is visualized. Things. The developer is used repeatedly while replenishing the toner consumed by the development. Therefore, during long-term use,
The toner particles must always be frictionally charged to the desired polarity and to a sufficient charge amount. However, in a conventional developer, a toner film is formed on the carrier surface by mechanical collisions such as collisions between particles or collisions between particles and a developing machine or heat generated by these collisions, so-called spent is caused, and the charging characteristics of the carrier are used. It decreases over time, requiring the entire developer to be replaced.

[0004] In order to prevent the spent toner from adhering to the carrier, a coating layer is generally provided on the carrier (JP-A-57-660 and JP-A-96357). There is also an example in which carbon, a silane coupling agent, a triboelectric charge controlling agent, and the like are provided in the coating layer. When the above-mentioned coating layer is exposed to ozone generated from a charger in a copying machine or a printer, the charge amount (hereinafter Q / M: coulomb / gr) with the toner becomes unstable, thereby causing background smearing and image deletion. Quality is significantly impaired.

[0005] The one-component developer is considered to charge the toner by frictional charging between the toner and the plate-like carrier when forming a thin film of the toner on a plate-like carrier having at least a binder resin layer provided on a substrate. However, also in this case, if the carrier is exposed to ozone, the charging of the toner becomes unstable as in the two-component developing method.

That is, in any of the one-component and two-component development methods, when the carrier coating layer is exposed to ozone, the characteristics of the coating layer are likely to deteriorate. In particular, Q / M deterioration becomes remarkable in this characteristic. Usually, there is no problem if Q / M is about 10 to 30 μc / g.
However, when exposed to ozone, the Q / M becomes 10 μc / g or less, causing background fouling, toner scattering in the developer, and optical system fouling in the machine.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to prevent a carrier coating layer of a dry developer from being deteriorated by ozone.

[0008]

The present invention is intended to solve the above-mentioned disadvantages by dispersing n-type semiconductor fine particles carrying a metal having an ozone decomposing action in a carrier coating layer.
Further, it is intended to reduce the concentration of ozone discharged outside the apparatus.

In an electrophotographic toner carrier having a coating layer made of at least a binder resin, the problem is solved by an electrophotographic toner carrier in which n-type semiconductor fine particles carrying a metal are dispersed in the coating layer. is there.

Further, it has been found that the optimum amount of the metal of the n-type semiconductor fine particles carrying the metal is 0.5% to 60% with respect to the binder resin. No effect if less than 0.5%, 6
If it is 0% or more, the adhesiveness to the core material is weakened and the core material is easily peeled. In addition, there is a disadvantage that a crack is easily formed in the coating layer during coating. Desirably, 0.7 to 45% is good.

As the n-type semiconductor fine particles used in the present invention, titanium oxide, zinc oxide, titanium hydroxide, zinc hydroxide, tin oxide, cadmium sulfide, tungsten oxide and the like can be used, but titanium oxide is preferable. As the titanium oxide used in the present invention, there are those manufactured by a sulfuric acid method and a chlorine method, and all of rutile type, anatase type, amorphous type and a mixed type thereof can be used. Examples of titanium oxide include P-25 (manufactured by Nihon Aerosil Co.): IT
-S, IT-PB, IT-PC (all manufactured by Idemitsu Kosan Co., Ltd.): R-820, R-830, R-680, CR-5
0, CR-60, A-100, A-220 (all manufactured by Ishihara Sangyo Co., Ltd.): JA-1, JA-2, JR, JRNC,
JR600E, MT-150W, MT-500B, MT
-600B (both manufactured by Teica).

As the metal to be carried, gold, silver, platinum and the like are preferable. As a supporting method, mechanical attachment may be used, but J. Chem. Soc., Faraday Trans. 79 (1) 2
685 (1983) is preferred. this is,
In this method, n-type semiconductor fine particles such as titanium oxide are dispersed in an aqueous solution containing metal ions such as gold, silver, and platinum, a small amount of alcohol is added, and ultraviolet light is applied to carry the metal on the fine particles. These are known to reduce ozone and the like at a portion of a supported metal and oxidatively decompose organic substances such as ammonium ions on a semiconductor surface.

The resin for coating the carrier used in the present invention includes, for example, polystyrene, polychlorostyrene,
Poly-α-methylstyrene, styrene-chlorostyrene copolymer, styrene-propylene copolymer, styrene-butadiene copolymer, styrene-vinyl chloride copolymer, styrene-vinyl acetate copolymer, styrene-maleic acid copolymer Polymer, styrene-acrylate copolymer (styrene-
Methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-phenyl acrylate copolymer), styrene-methacrylate Copolymers (styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, butyl methacrylate copolymer, styrene-phenyl methacrylate copolymer, etc.), styrene-α-methyl methacrylate copolymer Styrene resin such as styrene-acrylonitrile-acrylate copolymer (homopolymer or copolymer containing styrene or substituted styrene), vinyl chloride resin, styrene-vinyl acetate copolymer, rosin-modified maleic acid Resin, phenolic resin, epoxy resin, polyester resin, ionomer resin Polyurethane resins, silicone resins, ketone resins, ethylene - ethyl acrylate copolymer, xylene resin, polyvinyl butyral resin, include fluorine resin, these resins may be used singly, or two or more kinds.

The carrier core material has an average particle size of 20 to 10
Conventionally used materials such as non-metals such as cobalt, iron, copper, nickel, zinc, aluminum, ferrite, magnetite, brass, and glass having a thickness of 00 μm, preferably 30 to 100 μm, metals and metal alloys are widely used. The resin-coated carrier of the present invention is spray-coated,
Manufactured by methods such as dip coating. In the coating layer, if necessary, carbon as a conductive substance,
Metal, titanium oxide, zinc oxide, or the like may be added. Further, a material known to be used in a toner and a carrier, such as a phthalocyanine pigment, a quaternary ammonium salt, silica, a dye, a resin, a silane coupling agent, and a titanium coupling agent, may be added as a charge imparting substance.

The plate-shaped carrier is formed by providing the above-mentioned belt-shaped or drum-shaped coat layer made of metal, resin, or cloth.

As the toner used together with the carrier of the present invention, any known toner can be used. As the binder resin, all of those which have been used as a binder resin for a toner can be applied. Specifically, polystyrene,
Homopolymers of stellene such as polychlorostyrene and polyvinyltoluene and substituted products thereof. Styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer,
Styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate Copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene Styrene copolymers such as butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer, styrene-maleic acid copolymer, and styrene-maleic acid ester copolymer; Polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester,
Polyvinyl butyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, phenol resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin,
Chlorinated paraffin, paraffin wax and the like can be mentioned, and these may be used alone or as a mixture of two or more.

As the pigments and dyes, all of the conventionally used pigments, dyes and polarity controlling agents can be applied. Specifically, ultramarine, nigrosine dye, aniline blue, calco oil blue, Dupont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue,
Phthalocyanine green, rhodamine 6C lake, quinacridone, benzidine yellow, maranaide green, hansa yellow G, malachide green hexalate, oil black, azo oil black, rose bengal, monoazo dyes, disazo dyes, trisazo dyes And quaternary ammonium salts, metal salts of salicylic acid and salicylic acid derivatives, and mixtures thereof.

Examples of the release agent include synthetic waxes such as low molecular weight polyethylene and polypropylene, vegetable waxes such as candelilla wax, carnauba wax, rice wax, wood wax, jojoba oil, beeswax, lanolin, and the like. Animal waxes such as whale wax, montan wax, mineral waxes such as ozokerite, hardened castor fat, hydroxystearic acid, fatty acid amide,
Fatty oil waxes such as phenol fatty acid esters and the like can be mentioned. In addition to the above components, the toner of the present invention may contain various plasticizers (such as dibutyl phthalate and dioctyl phthalate) for the purpose of adjusting the thermal, electrical, and physical properties of the toner as needed. It is also possible to add an auxiliary agent such as a resistance adjusting agent (tin oxide, lead oxide, achimon oxide, etc.).

[0019]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Production Examples, Examples and Comparative Examples in order to more clearly understand the present invention, but these are not intended to limit the present invention in any way.

Production Example 1 In a 1000 ml flask, 0.5 g of titanium oxide (MT-150W manufactured by Teica) dried at 110 ° C. for 24 hours was dispersed in 50 ml of an aqueous solution of silver sulfate, and 0.3 g of isopropanol was further added. The resulting suspension was purged with argon gas for 30 minutes and
UV light was applied for hours. Thereafter, the suspension was subjected to suction filtration, and the filtrate was washed with diluted sulfuric acid and dried at 110 ° C. for 4 hours. It was pulverized in an agate mortar to obtain a powdery substance. Production Example 2 In a 1000 ml flask, 0.5 g of titanium oxide (P-25 manufactured by Nippon Aerosil Co., Ltd.) dried at 110 ° C. for 24 hours was dispersed in 50 ml of an aqueous solution of silver sulfate, and 0.3 g of isopropanol was further dispersed.
added. The resulting suspension was purged with argon gas for 30 minutes and irradiated with ultraviolet light for 5 hours. Thereafter, the suspension was subjected to suction filtration, the filtrate was washed with dilute sulfuric acid, and dried at 110 ° C. for 4 hours. It was pulverized in an agate mortar to obtain a powdery substance. Production Example 3 In a 1000 ml flask, 0.5 g of titanium oxide (MT-150W manufactured by Teica) dried at 110 ° C. for 24 hours was dispersed in 50 ml of an aqueous solution of hexachloroplatinic acid, and isopropanol was further added.
0.3 g was added. The resulting suspension was purged with argon gas for 30 minutes and irradiated with ultraviolet light for 5 hours. Thereafter, the suspension was subjected to suction filtration, the filtrate was washed with dilute sulfuric acid, and dried at 110 ° C. for 4 hours. It was pulverized in an agate mortar to obtain a powdery substance.

Example 1 Toner Example A mixture having the following formulation was kneaded on a two-roll mill under heating, cooled, and pulverized and classified to prepare a toner for a two-component developer having a particle size of 5 to 20 μm. 100 parts by weight of polystyrene (D-125 manufactured by Esso) 5 parts by weight of metal-containing pigment (Spiron Black BH manufactured by Hodogaya Chemical Co., Ltd.) 10 parts by weight of carbon black (# 44 manufactured by Mitsubishi Kasei Co., Ltd.) To prepare a coating solution. Silicone resin liquid (Toray Silicone RS2406, solid content 20%) 500 parts by weight Compound of Preparation Example 1.5 parts by weight Toluene 1500 parts by weight An average particle diameter of 50 μm is applied to a rotating disk type fluid particle coating apparatus.
5 kg of ferrite carrier is applied and the coating liquid of the above formulation is applied under heating at 80 ° C. while flowing, and the applied material is taken out of the coating apparatus, placed in a thermostat, and heated at 200 ° C. for 2 hours to form a silicone film. Curing was performed.

Example 2 Toner Example A mixture having the following formulation was kneaded on a two-roll mill under heating, cooled, pulverized and classified to prepare a two-component developer toner having a particle size of 5 to 20 μm. 100 parts by weight of polystyrene (D-125 manufactured by Esso) 5 parts by weight of metal-containing pigment (Spiron Black BH manufactured by Hodogaya Chemical Co., Ltd.) 10 parts by weight of carbon black (# 44 manufactured by Mitsubishi Kasei Co., Ltd.) To prepare a coating solution. Silicone resin liquid (Toray Silicone RS2406, solid content 20%) 500 parts by weight Conductive carbon 3 parts by weight Compound of Production Example 1 1.5 parts by weight Toluene 1500 parts by weight An average particle size of 50 μm is applied to a rotating disk type fluid type particle coating apparatus.
5 kg of ferrite carrier is applied and the coating liquid of the above formulation is applied under heating at 80 ° C. while flowing, and the applied material is taken out of the coating apparatus, placed in a thermostat, and heated at 200 ° C. for 2 hours to form a silicone film. Was cured.

Example 3 Toner Example A mixture having the following formulation was kneaded on a two-roll mill with heating, cooled, and pulverized and classified to prepare a toner for a two-component developer having a particle size of 5 to 20 μm. Polystyrene (D-125, manufactured by Esso Corporation) 100 parts Metal-containing pigment (Spilon Black BH, manufactured by Hodogaya Chemical Co., Ltd.) 5 parts Carbon black (# 44 manufactured by Mitsubishi Kasei Co., Ltd.) 10 parts Carrier example Coating solution as carrier coating material by the following formula Was adjusted. Silicone resin liquid (Toray Silicone RS2406, solid content 20%) 500 parts by weight Conductive carbon 3 parts by weight Compound of Production Example 1 1.5 parts by weight Silane coupling agent 1.5 parts by weight Toluene 1500 parts by weight Rotating disk type fluid particle coating device Average particle size 50μ
5 kg of ferrite carrier is applied and the coating liquid of the above formulation is applied under heating at 80 ° C. while flowing, and the applied material is taken out of the coating apparatus, placed in a thermostat, and heated at 200 ° C. for 2 hours to form a silicone film. Was cured.

Examples 4 to 6 and Comparative Examples 1 and 2 In Example 3, the amount of the compound of Production Example 1 in the carrier coating layer was changed as shown in Table 1.

[0025]

[Table 1]

Example 7 In Example 3, Production Example 1 in which the carrier was coated was replaced with Production Example 2.
Replaced with

In Examples 1 to 7 and Comparative Examples 1 and 2,
100 parts by weight of the carrier and 30 parts by weight of the toner were mixed to prepare a negatively charged developer, and the Ricoh FT
Table 2 shows the results of a continuous paper passing test performed by setting the printer on a 4420 machine.

[0028]

[Table 2]

In Comparative Example 2, the toner adhered to the carrier due to the carrier film displacement, and the Q / M was reduced. In addition, the toner was scattered and was very dirty.

[0030]

【The invention's effect】

(1) a carrier for toner comprising a core particle surface coated with a binder resin; (2) a toner carrier comprising a layer in which magnetic particles are dispersed in a binder resin; (3) By dispersing and presenting n-type semiconductor particles carrying a metal on the coating layer of the toner carrier, which is formed by coating the binder resin layer on the substrate, the charge amount of the developer changes over a long period of use. Without this, a developer having excellent development characteristics can be obtained.

Continued on the front page (72) Inventor Takahisa Kato 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company (72) Inventor Tomomi Suzuki 1-3-6 Nakamagome, Ota-ku, Tokyo Stock Company Ricoh (56) References JP-A-64-7046 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 9/113

Claims (2)

(57) [Claims] 1. An electrophotographic toner carrier having a coating layer made of at least a binder resin, wherein n-type semiconductor fine particles supporting a metal are dispersed in the coating layer. Career. 2. The carrier for an electrophotographic toner according to claim 1, wherein the metal of the n-type semiconductor fine particles carrying the metal is 0.5% to 60% with respect to the binder resin.