JP2007047768A - Conductive roller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conductive roller whose image defect such as a vertical stripe or white fogging is eliminated by preventing the filming of toner on the surface of the conductive roller. <P>SOLUTION: The conductive roller includes: a conductive supporting member 1; an elastic layer 2 formed on the outer peripheral surface of the supporting member; and a covering layer 3 formed on the outer peripheral surface of the elastic layer and exposed to the outermost surface. The covering layer is composed of composite material containing (A) thermoplastic resin, (B) particulates containing silicone modified by an organic compound containing at least a kind of element selected from a group comprising oxygen, nitrogen and sulfur, and (C) a conductivity imparting agent as an indispensable component. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a conductive roller that can be suitably used in an electrophotographic developing device such as a copying machine, a printer, or a facsimile machine.

The electroconductive roller is used in an electrophotographic developing device in applications such as a charging roller, a developing roller, and a fixing roller. The required characteristics as the electroconductive roller differ depending on each application.
(Non-magnetic one-component contact development type development roller)
For example, in a non-magnetic one-component contact development method which is one of the electrophotographic methods, the developing roller has a function of conveying toner to an electrostatic latent image carrier such as a photoconductor. The quality required for the developing roller in such applications includes surface irregularities suitable for toner conveyance, surface properties excellent in toner releasability, conductivity suitable for toner charging, low hardness, low compression strain, and the like.
(Lower melting point of toner)
By the way, there is a great market demand for increasing the printing speed of copiers, printers, etc., and the electrophotographic method is a method that responds to this, but in order to achieve even higher speeds, toner is fixed on paper. In order to shorten the time, specifically, lowering the melting point of toner is being promoted. However, by lowering the melting point of the toner, there arises a problem that the toner is easily fused to each member in contact with the toner.
(Relationship between contact development and filming)
In particular, in the case of a contact developing type developing roller, frictional heat is likely to occur due to contact between the photosensitive member, the blade, the toner leakage prevention member, etc. and the developing roller. The problem of fusing (filming) is likely to occur. When printing is continued in a state where such filming has occurred, image defects such as vertical stripes and white background fogging occur in the printed matter.
(Conventional toner filming improvement technology)
As a technique for preventing such filming from occurring in the roller, that is, as a technique for improving toner filming, a technique using fluorine rubber or hydrogenated nitrile rubber as the material of the outermost surface of the roller (for example, Patent Document 1), a technique using a material cured by applying cyanoacrylate (for example, Patent Document 2), a technique for adding silicone oil or fluorine-based oil to the outermost surface resin of the roller (for example, Patent Document 3), etc. There is.
JP-A-5-107874. JP-A-8-297409. Japanese Patent Laid-Open No. 9-90736.

  The present invention has been made in view of such a situation, and provides a conductive roller that prevents filming of toner on the surface of the conductive roller and improves image defects such as vertical stripes and white background fog. . That is, the conventional technique has a problem that, as in Patent Documents 1 and 2, for example, it is necessary to change the surface layer material, and any surface layer material cannot be applied. However, since the oil component is contained in the surface layer, contamination of the toner and other members becomes a problem. The present invention solves these problems.

  The present inventors have made extensive studies and found that the above-mentioned problems can be solved by the conductive roller of the present invention.

That is, the conductive roller of the present invention includes a conductive support member, an elastic layer formed on the outer peripheral surface of the support member, and a coating layer formed on the outer peripheral surface of the elastic layer and exposed on the outermost surface. The coating layer is made of a composite material containing the following components (A) to (C) as essential components, and (B) the fine particles made of silicone are uniformly dispersed on the roller surface. In addition, since the inherent characteristics of silicone such as slipperiness and water repellency are sufficiently exhibited, the conductive roller is excellent in preventing toner filming.
(A) Thermoplastic resin.
(B) Silicone fine particles modified with a modifying organic compound containing at least one element selected from the group consisting of oxygen, nitrogen, and sulfur.
(C) Conductivity imparting agent.

  The component (A) is preferably a thermoplastic urethane resin, which is a conductive roller having excellent wear resistance.

  In addition, the modifying organic compound is preferably an acrylic compound and / or an epoxy compound, and since the compatibility with the component (A) is excellent, the component (B) is uniformly formed in the coating layer. Dispersed, the filming resistance is uniformly excellent on the roller surface, and the roller has a strong coating layer because of excellent adhesion to the adjacent layer.

  The coating layer preferably further contains an organic filler having an average particle diameter of 1 to 30 μm. Surface properties relating to toner releasability such as slidability to the roller surface by the component (B). Irrespective of direct application to the roller, surface irregularities suitable for toner conveyance can be applied to the roller.

Furthermore, the elastic layer is preferably a cured product of a curable composition containing the following components (D) to (G) as essential components, and the curable composition has a molecular weight and a functional group weight. Since the physical properties of the cured product can be easily controlled by changing the hardness, it is easy to control the hardness of the obtained roller to a value suitable for a roller incorporated in an image forming apparatus using an electrophotographic system. Can be.
(D) An organic polymer having at least one alkenyl group capable of hydrosilylation reaction in the molecule.
(E) A compound having at least two hydrosilyl groups in the molecule.
(F) Hydrosilylation catalyst.
(G) Conductivity imparting agent.

  Such a conductive roller of the present invention is suitably used as a developing roller.

  The conductive roller of the present invention is an organic compound containing at least one element selected from the group consisting of (A) oxygen, nitrogen and sulfur on the outermost surface thereof (A) having good compatibility with the thermoplastic resin. Since it has a coating layer containing fine particles of modified silicone, the fine particles of (B) silicone are uniformly dispersed on the roller surface, and the original characteristics of silicone such as slipperiness and water repellency are fully exhibited. Therefore, the conductive roller is excellent in preventing toner filming.

Hereinafter, embodiments of the present invention will be described in detail.
(Figure 1: Example of a three-layer structure)
FIG. 1 is a cross-sectional view of a conductive roller according to the present invention. In this conductive roller, an elastic layer 2 is provided around the conductive support member 1, and a coating layer 3 is formed on the elastic layer 2.
(Conductive support member)
The conductive support member 1 is preferably a rod-shaped member having a diameter of about 1 mm to 25 mm made of SUS (stainless steel), SUM material (free-cutting steel material), aluminum alloy, or conductive resin.
(Elastic layer)
The elastic layer 2 is preferably an essential component (D) an organic polymer having at least one hydrosilylation-reactive alkenyl group in the molecule, (E) a compound containing at least two hydrosilyl groups in the molecule, (F) A cured product of a curable composition containing a hydrosilylation catalyst and (G) a conductivity-imparting agent. The said curable composition can control the physical property of the hardened | cured material obtained easily by changing molecular weight and the amount of functional groups.

In the present invention, such a cured product is used in a roller incorporated in an image forming apparatus using an electrophotographic method. Therefore, the hardness of the cured product is not excessively increased, and a large stress is applied to the toner. In order to avoid this, it is preferable that the ASKER-C hardness is 20 ° to 80 °, and in particular, 30 ° to 70 ° when used for a developing roller that conveys toner while being in contact with other members. Is preferred. The measuring method of ASKER-C hardness here is based on JISK6301 except the thickness of the hardened | cured material used as object being 4 mm.
(Elastic layer forming method)
A method for forming such an elastic layer 2 is not particularly limited, and conventionally known methods for forming various types of rollers can be used. For example, a mold having a conductive support member 1 at the center is hardened. The composition is molded by various molding methods such as extrusion molding, press molding, injection molding, reaction injection molding (RIM), liquid injection molding (LIM), and cast molding, and heated and cured at an appropriate temperature and time. There is a method of forming the elastic layer 2 around the conductive support member 1, and in the present invention, since the curable composition before curing described above is liquid, particularly from the viewpoint of productivity and workability, liquid injection molding is particularly preferred. (LIM) is preferred. In this case, after the curable composition is semi-cured in a mold, a separate post-curing process may be provided for complete curing.
((D) component: organic polymer: base polymer)
The component (D) is a base polymer of the elastic layer 2 that is cured by a hydrosilylation reaction with the component (E), and an alkenyl group is introduced into an oligomer that becomes a main chain portion.
(Main chain portion of component (D))
Moreover, the main chain part of the organic polymer of the said (D) component can be selected from arbitrary polymers, and is not restrict | limited in particular. Examples thereof include polyisoprene, polybutadiene, polyisobutylene, polychloroprene, polyoxyalkylene, polysiloxane, and polysulfide. In particular, a polymer composed of oxyalkylene units is easy to handle because of its low viscosity before curing, and when used in an elastic roller application, the cured product has a particularly flexible structure. Is preferable in that it sufficiently exhibits its elastic effect.

  Further, the oxyalkylene polymer is preferably a polymer in which 30 mol% or more, preferably 50 mol% or more of units constituting the main chain are oxyalkylene units. The oxyalkylene unit does not have to be one kind, and may be a copolymer (including a graft polymer) made of ethylene oxide, propylene oxide, butylene oxide, or the like. In terms of environmental stability of electrical characteristics, it is preferable that the main chain skeleton is a polymer having relatively low water absorption, or a polymer composed of oxybutylene units. In consideration of cost, the polymer composed of oxypropylene units is Is particularly preferred. In addition to the oxyalkylene unit, the unit contained is a compound having two or more OH groups, for example, ethylene glycol, a bisphenol compound, glycerin, trimethylolpropane, used as a starting material for polymer production. And units that can be derived when pentaerythritol or the like is used.

The molecular weight of the polyoxyalkylene polymer as described above is 500 to 50,000 in terms of number average molecular weight (Mn) (GPC method, in terms of polystyrene), the ease of handling, and the rubber elasticity after curing. This is preferable. When the number average molecular weight is less than 500, it becomes difficult to obtain sufficient mechanical properties (rubber hardness, elongation) and the like when the curable composition is cured. On the other hand, when the number average molecular weight is 50,000 or more, the molecular weight per alkenyl group contained in the molecule is increased or the reactivity is lowered due to steric hindrance, so that curing is often insufficient. Also, the viscosity tends to be too high and the processability tends to deteriorate.
(Alkenyl group of component (D))
The alkenyl group in the component (D) is not particularly limited as long as it is a group containing a carbon-carbon double bond that is active for the hydrosilylation reaction. Examples of the alkenyl group include aliphatic unsaturated hydrocarbon groups such as vinyl group, allyl group, methylvinyl group, propenyl group, butenyl group, pentenyl group, and hexenyl group, cyclopropenyl group, cyclobutenyl group, cyclopentenyl group, and Examples thereof include a cyclic unsaturated hydrocarbon group such as a cyclohexenyl group, a methacryl group, and the like, and an alkenyl group represented by the following general formula 1 is particularly preferable from the viewpoint of excellent curability.

（式中、Ｒ¹は水素原子またはメチル基）
また、このようなアルケニル基がその重合体末端に導入されているものであることが、最終的に得られる硬化物の有効網目鎖量が多くなり、高強度のゴム状硬化物が得られやすくなることから好ましい。

(Wherein R ¹ is a hydrogen atom or a methyl group)
In addition, the fact that such an alkenyl group is introduced at the end of the polymer increases the effective network chain amount of the finally obtained cured product, and it is easy to obtain a high-strength rubber-like cured product. This is preferable.

Such component (D) reacts with the OH group of the oligomer that becomes the main chain portion, for example, when an oligomer having an OH group corresponds to the main chain portion like the main chain portion described above. It can be obtained by reacting a compound containing both a functional group having a property and an alkenyl group, for example, allyl chloride with the oligomer.
(Curing agent: (E) component)
The component (E) is a compound that functions as a curing agent that cures by hydrosilylation reaction with the component (D), and is not particularly limited as long as it is a compound having at least two hydrosilyl groups in one molecule. If the number of hydrosilyl groups contained in the molecule of the compound is too large, a large amount of hydrosilyl groups tend to remain in the cured product even after curing, and this residual hydrosilyl group causes voids and cracks. Is preferably adjusted to 50 or less, and more preferably adjusted to 2 to 30 in order to obtain a suitable value for the rubber elasticity of the cured product and sufficient storage stability. preferable. In the present invention, having one hydrosilyl group means having one H bonded to Si. Therefore, in the case of SiH ₂ , it has _two hydrosilyl groups. However, in the present invention, H bonded to Si is bonded to different Si, in the present invention, (D) component and (E) component From the viewpoints of curability due to this reaction and rubber elasticity of the fallout obtained by the cure.

  The molecular weight of such a curing agent is preferably adjusted to 30,000 or less in terms of number average molecular weight (GPC method, polystyrene conversion) (Mn) from the viewpoint of improving the workability of the molded article. From the viewpoint of improving the reactivity and compatibility with the base polymer, it is more preferable to adjust Mn to 300 to 10,000.

In addition, in consideration of the fact that the cohesive force of the base polymer tends to be larger than that of the hardener in general, such a curing agent is particularly preferably a phenyl group-containing modified product in terms of compatibility. Of these, from the viewpoint of availability, it is preferable to use a styrene-modified product, and from the viewpoint of storage stability, it is preferable to use an α-methylstyrene-modified product.
((F) Hydrosilylation catalyst)
The component (F) is a hydrosilylation catalyst that causes the hydrosilylation reaction of the component (D) and the component (E), and any catalyst can be used without particular limitation as long as it has the catalytic action. Specifically, chloroplatinic acid, platinum alone,
For example, solid platinum supported on a carrier such as alumina, silica and carbon black,
Platinum-olefin complexes,
For example, a platinum-vinylsiloxane complex represented by Pt _n (ViMe ₂ SiOSiMe ₂ Vi) _m and Pt [(MeViSiO) ₄ ] _m
For example, platinum-phosphine complexes represented by Pt (PPh ₃ ) ₄ and Pt (PBu ₃ ) ₄
For example, platinum-phosphite complexes represented by Pt [P (OPh) ₃ ] ₄ and Pt [P (OBu) ₃ ] ₄
Pt (acac) ₂ ,
A platinum-hydrocarbon complex described in U.S. Pat. Nos. 3,159,601 and 3,159,662 to Ashby et al., And
A platinum alcoholate catalyst as described in US Pat. No. 3,220,972 to Lamoreaux et al.,
Etc. are exemplified.

Further, as the hydrosilylation catalyst as the component (F), catalysts other than platinum compounds can be used. For example, RhCl (PPh ₃ ) ₃ , RhCl ₃ , Rh / Al ₂ O ₃ , RuCl ₃ , IrCl ₃ FeCl ₃ , AlCl ₃ , PdCl ₂ .2H ₂ O, NiCl ₂ , TiCl _{4 and the} like.

  In the above general formulas and the like, Me represents a methyl group, Bu represents a butyl group, Vi represents a vinyl group, Ph represents a phenyl group, acac represents an acetylacetonate group, and n and m represent integers.

These catalysts may be used alone or in combination of two or more. From the viewpoint of catalytic activity, chloroplatinic acid, platinum-olefin complexes, platinum-vinylsiloxane complexes, Pt (acac) _{2 and the} like are preferable. Although there is no restriction | limiting in particular about the catalyst amount to be used, It is preferable to set it as the range of 10 ^{< -1} > ^-10 <^-8> mol with respect to ¹ mol of alkenyl groups in (D) component, and in order to fully advance hydrosilylation reaction More preferably, it is in the range of 10 ⁻² to 10 ⁻⁶ mol. In addition, hydrosilylation catalysts are generally expensive, and some of them are highly corrosive, and there is a concern that the cured product itself is corrosive. Further, a large amount of hydrogen gas is generated during the reaction, resulting in a foamed cured product. Therefore, it is better not to use 10 ⁻¹ mol or more with respect to ¹ mol of alkenyl group in component (D).
((G) conductivity imparting agent)
In a roller used in an electrophotographic apparatus, it is necessary to control from a conductive region to a semiconductive region (10 ⁴ to 10 ¹⁰ Ω), and therefore a conductivity imparting agent is generally added. The component (G) is a conductivity-imparting agent that is added to the curable composition for this purpose, and any known one can be used without any particular limitation. For example, carbon black, metal fine powder, Organic lithium salts, inorganic lithium salts and the like, and organic compounds or polymers having a quaternary ammonium base, a carboxylic acid group, a sulfonic acid group, a sulfate ester group, a phosphate ester group, etc. Compounds having conductive units represented by ester amide, ether imide polymer, ethylene oxide-epihalohydrin copolymer, methoxypolyethylene glycol acrylate, etc. The compound etc. which can be provided are mentioned. These conductivity-imparting agents may be used alone or in combination of two or more. Examples of the carbon black include furnace black, acetylene black, lamp black, channel black, thermal black, and oil black. There are no restrictions on the type and particle size of these carbon blacks.

The amount of the component (G) added to the curable composition can be adjusted according to the desired conductive properties, but sufficiently imparts conductivity to the elastic layer 2 and the viscosity of the curable composition is increased. From the viewpoint of ensuring the workability at the time of forming the elastic layer as an appropriate range, and further ensuring the elasticity of the elastic layer, preferably (G) with respect to 100 parts by weight of the organic polymer of component (D) The component is preferably 0.01 to 100 parts by weight, more preferably 0.1 to 50 parts by weight. Further, depending on the type or addition amount of the conductivity-imparting agent used, there are those that inhibit the hydrosilylation reaction, so it is preferable to consider the influence of the conductivity-imparting agent on the hydrosilylation reaction.
(Storage stability improver)
For the purpose of improving storage stability, it is preferable to add a storage stability improving agent to the curable composition according to the present invention. As such a storage stability improver, a stabilizer known as a storage stabilizer for the component (E) can be preferably used, but is not particularly limited as long as the object is achieved. Specifically, a compound containing an aliphatic unsaturated bond, an organic phosphorus compound, an organic sulfur compound, a nitrogen-containing compound, a tin-based compound, an organic peroxide, and the like can be exemplified. More specifically, 2-benzothiazolyl sulfide, benzothiazole, thiazole, dimethylacetylene dicarboxylate, diethylacetylene dicarboxylate, butylhydroxytoluene, butylhydroxyanisole, vitamin E, 2- (4-morphodinyl) Dithio) benzothiazole, 3-methyl-1-buten-3-ol, acetylenically unsaturated group-containing organosiloxane, ethylenically unsaturated group-containing organosiloxane, acetylene alcohol, 3-methyl-1-butyl-3-ol, Examples include 3-methyl-1-pentyn-3-ol, diallyl fumarate, diallyl maleate, diethyl fumarate, diethyl maleate, dimethyl maleate, 2-pentenenitrile, and 2,3-dichloropropene.

Furthermore, various fillers, various function-imparting agents, antioxidants, ultraviolet absorbers, pigments, surfactants, and solvents may be appropriately added to the curable composition as necessary. Specific examples of the filler include silica fine powder, metal fine powder, calcium carbonate, clay, talc, titanium oxide, zinc white, diatomaceous earth, and barium sulfate.
(Coating layer)
The coating layer 3 according to the present invention is composed of a composite material containing (A) a thermoplastic resin, (B) silicone fine particles modified with an organic compound for modification, and (C) a conductivity-imparting agent as essential components. It is the outermost layer exposed on the outermost surface of the roller. The thickness of the coating layer 3 is set to an appropriate value depending on the material, composition, application, and the like to be used, but is usually preferably 1 to 100 μm in average thickness, and particularly the elastic layer 2. 3 μm to 30 μm is preferable in order to suitably exhibit the rubber elasticity. When it becomes thinner than 1 μm, the wear resistance is lowered, and the long-term durability tends to be lowered. On the other hand, if it is thicker than 100 μm, there may be a problem that wrinkles are likely to occur or the compressive strain is increased due to the difference in linear expansion coefficient with the elastic layer.
(Figure 2: Example of a four-layer structure: intermediate layer 4)
Since the coating layer 3 according to the present invention exhibits excellent filming prevention properties when it is the outermost layer exposed on the outermost surface of the conductive roller, for example, as shown in FIG. 2, the intermediate layer 4 is an elastic layer. 2 and the covering layer 3 may be inserted. In addition, in an elastic roller whose hardness has been reduced by adding a plasticizer or the like to the material of the elastic layer, bleed, which is a phenomenon in which the plasticizer diffuses to the roller surface, may become a problem. It is preferred to insert layer 4. When the intermediate layer 4 is made to function as such a bleed suppressing layer, the material of the intermediate layer 4 is a non-polar resin such as an olefin resin, a styrene resin, or a silicone resin if the bleed material is a polar compound. On the contrary, if the bleed material is a nonpolar compound, urethane resin, nylon resin, acrylic resin, and the like are preferable.
((A) Thermoplastic resin)
The (A) thermoplastic resin is not particularly limited as long as it is a general thermoplastic resin. However, when elasticity is required not only for the entire roller but also for the roller surface itself, a thermoplastic elastomer is preferable. Specific examples include thermoplastic elastomers such as olefins, styrenes, esters, amides, urethanes, acrylics, silicones, and vinyl chlorides. Among these, rollers are wear resistant. Therefore, urethane-based thermoplastic elastomers are particularly preferable.

Moreover, in order to improve the resin strength of the thermoplastic resin as the component (A) and further improve the adhesion to the elastic layer 2 and the intermediate layer 4, such as silica, calcium carbonate, talc, and clay. You may add various additives, such as a filler and a coupling agent, as needed. Further, in order to reduce stress on the toner, the thermoplastic resin which is the outermost surface preferably has a low hardness and a low elastic modulus.
((B) Silicone fine particles modified with an organic compound for modification)
The silicone fine particles modified with the modifying organic compound of the component (B) are a modifying organic compound containing a compound having a siloxane bond and at least one element selected from the group consisting of oxygen, nitrogen and sulfur. Are silicone fine particles synthesized by copolymerization. Examples of such a copolymerization method include block copolymerization and graft copolymerization. Graft copolymerization is preferable because the silicone fine particles can be synthesized relatively easily.

  Specifically, the compound having a siloxane bond is a polyorganosiloxane having a functional group capable of reacting with the modifying organic compound. For example, a polyorganosiloxane having a methacryloxypropyl group synthesized by hydrosilylation reaction of a polyorganosiloxane containing a hydrosilyl group (SiH group) and allyl methacrylate can react with the modifying organic compound. It is a polyorganosiloxane having a methacryloxypropyl group as a functional group.

  Thereafter, for example, acrylic modified silicone fine particles can be synthesized by radical polymerization of an acrylic acid ester which is the modifying organic compound and a compound having a siloxane bond.

  As described above, it is preferable from the viewpoint of synthesis that the modifying organic compound and the polyorganosiloxane having a functional group capable of reacting therewith are radically polymerized as described above.

  Further, as other copolymerizable components capable of radical polymerization, vinyl monomers may be included, and specific examples include, but are not limited to, ethylene, propylene, butadiene, isoprene, chloroprene, and styrene. is not.

Further, the silicone fine particles modified with the modifying organic compound as the component (B) may contain other optional components as long as they are within the range having the effects of the present invention.
(Polyorganosiloxane skeleton)
The skeleton of the polyorganosiloxane is not particularly limited, and examples thereof include dimethylsiloxane, methylphenylsiloxane, diphenylsiloxane, alkyl (C2 or higher alkyl group) methylsiloxane, and dialkylsiloxane. These skeletons may be used alone or in combination of two or more.
(Organic compound for modification)
Examples of the modifying organic compound include, but are not limited to, organic compounds having a functional group represented by the following general formula 2.

（Ｒ₁〜Ｒ₄は任意の１価の有機基あるいは水素原子であれば良く、互いに同一であっても、一部が同一で一部が異なっていても、互いに異なっていてもよい。例えばＲ₁〜Ｒ₄はメチル基、エチル基、及び水酸基等も挙げられる。）
このような変性用有機化合物は、前記シロキサン結合を有する化合物に対して、シロキサン結合を有する化合物：変性用有機化合物が、５重量部：９５重量部〜９５重量部：５重量部として共重合することが好ましく、シリコーン由来の撥水性や摺動性、及び変性用有機化合物由来の相溶性やその他の特性を十分に付与するために、１０重量部：９０重量部〜９０重量部：１０重量部として重合することがさらに好ましい。

(R _{1 to} R ₄ may be any monovalent organic group or hydrogen atom, and may be identical to each other, partially identical, partially different, or different from each other. R _{1 to} R _{4 also} include a methyl group, an ethyl group, and a hydroxyl group.)
In such a modifying organic compound, the compound having a siloxane bond: the modifying organic compound is copolymerized in an amount of 5 parts by weight: 95 parts by weight to 95 parts by weight: 5 parts by weight with respect to the compound having the siloxane bond. In order to sufficiently impart water repellency and slidability derived from silicone, compatibility derived from a modifying organic compound, and other characteristics, 10 parts by weight: 90 parts by weight to 90 parts by weight: 10 parts by weight It is more preferable to polymerize as.

  The component (B) preferably contains an organic compound containing at least one element selected from the group consisting of oxygen, nitrogen and sulfur in terms of imparting compatibility with the thermoplastic resin. In the general formula 2, acrylic compounds and epoxy compounds are particularly preferable, and these may be used alone or in combination.

Silicone fine particles modified with an acrylic compound, when a compound having oxygen and nitrogen atoms such as urethane, amide, ester group, and acrylic is used as the thermoplastic resin of the component (A), The compatibility is particularly excellent because it is excellent. Silicone fine particles modified with an epoxy compound are more preferable because they are excellent in adhesiveness with the elastic layer 2 or the intermediate layer 4 that is in contact with the coating layer 3.
(Acrylic compound)
The acrylic compound is not particularly limited, and a general monomer having a functional group as shown in the following general formula 3 can be used. Specifically, methyl acrylate, ethyl acrylate, n-propyl Examples include acrylate, isopropyl acrylate, n-butyl acrylate, i-butyl acrylate, t-butyl acrylate, pentyl acrylate, hexyl acrylate, lauryl acrylate, stearyl acrylate, phenyl acrylate, aryl acrylate, and acrylonitrile. Also included are methacrylates.

（Ｒ₁〜Ｒ₃はアルキル基、アルケニル基、アルキニル基、及びアリール基等の任意の１価の有機基あるいは水素原子であれば良く、互いに同一であっても、一部が同一で一部が異なっていても、互いに異なっていてもよい。）
（エポキシ系化合物）
このようなエポキシ系化合物としては、特に限定はなく、下記一般式４に示すような官能基を有する一般的なモノマーを用いることができ、具体的には、エチレンオキサイド、プロピレンオキサイド、ブチレンオキサイド、及びアリルグリシジルエーテル等のグリシジル基含有化合物と、脂環式エポキシ化合物等とが挙げられる。

(R _{1 to} R ₃ may be any monovalent organic group such as an alkyl group, an alkenyl group, an alkynyl group, and an aryl group or a hydrogen atom. May be different or different from each other.)
(Epoxy compound)
Such an epoxy compound is not particularly limited, and a general monomer having a functional group as shown in the following general formula 4 can be used. Specifically, ethylene oxide, propylene oxide, butylene oxide, And glycidyl group-containing compounds such as allyl glycidyl ether, and alicyclic epoxy compounds.

（Ｒ₁〜Ｒ₄は任意の１価の有機基あるいは水素原子であれば良く、互いに同一であっても、一部が同一で一部が異なっていても、互いに異なっていてもよい。例えばＲ₁〜Ｒ₄はメチル基、エチル基、及び水酸基等も挙げられる。）
特に、前記（Ａ）成分と前記（Ｂ）成分との相溶性をさらに高めるためには両方の成分が同一の官能基を有することが好ましい。例えば、（Ａ）成分がアクリル系熱可塑性樹脂であれば、（Ｂ）成分の変性用有機化合物を前述したアクリル系化合物とすることが好ましい。

(R _{1 to} R ₄ may be any monovalent organic group or hydrogen atom, and may be identical to each other, partially identical, partially different, or different from each other. R _{1 to} R _{4 also} include a methyl group, an ethyl group, and a hydroxyl group.)
In particular, in order to further improve the compatibility between the component (A) and the component (B), it is preferable that both components have the same functional group. For example, if the component (A) is an acrylic thermoplastic resin, the modifying organic compound of the component (B) is preferably the acrylic compound described above.

  The particle diameter of the component (B) fine particles is not particularly limited, but the primary average particle diameter is preferably 0.01 to 30 μm, and the range of 0.05 to 10 μm is suitable for toner conveyance. Dispersibility in the thermoplastic resin can be ensured while maintaining an uneven surface, which is preferable because it is well balanced. Further, this particle system is preferably smaller than the film thickness of the coating layer, and since it becomes easy to uniformly disperse the component (B) in the component (A), the characteristics of the component (A) and the component (B) Both characteristics can be effectively expressed. For example, when the component (A) is a urethane-based thermoplastic resin and the component (B) is a silicone fine particle modified with an acrylic compound, the wear resistance of the urethane-based resin and the slidability due to the silicone fine particle It can be set as the coating layer which has. In the system of the components (A) and (B), on the contrary, when the primary particle diameter of the fine particles is larger than the film thickness of the coating layer, the protruding portion of the silicone fine particles modified with the acrylic compound on the coating layer surface becomes high, Although the slidability is preferably exhibited, the coating layer has a reduced wear resistance. Therefore, when a roller having such a coating layer is used as a developing roller, the surface state changes with time from the initial state. Therefore, problems such as a change in image density due to a change in toner conveyance amount and occurrence of image defects such as vertical stripes occur.

The weight ratio of the blending amount of the component (A) and the component (B) is preferably in the range of (A) :( B) = 99: 1 to 50:50, and more preferably 95: 5 to 70:30. The range of is more preferable. By including the component (B) in the composite material of the coating layer in the range of 1% by weight or more and 50% by weight or less, the sliding property due to the silicone fine particles can be effectively imparted to the coating layer, and elasticity Since it becomes a composite material with excellent coating properties on the layer or the intermediate layer, it can be a coating layer in which appearance defects such as cracks are unlikely to occur.
((C) conductivity imparting agent)
For the same purpose as the curable composition that is the material of the elastic layer 2 described above, the conductivity imparting agent that is the component (C) is also added to the composite material that is the material of the coating layer 3. As this (C) component, the material similar to the said (G) component can be used suitably.

The amount of the component (C) to be included in the composite material can be adjusted according to the desired conductive properties, but can sufficiently impart conductivity to the coating layer 3 and ensure the flexibility of the coating layer. From the viewpoint of preventing appearance defects such as cracks from occurring, the component (A) is preferably 0.01 to 100 parts by weight, more preferably 0.1 to 50 parts by weight, with respect to 100 parts by weight of the component (A). It is preferable to do.
(Organic filler)
In the case of using a non-magnetic one-component contact developing roller, in order to reduce toner conveyance and friction with other members, the coating layer and / or the intermediate layer 4 has an average particle diameter of 1 to 30 μm. It is preferable to add the organic filler. In particular, when added to the intermediate layer 4, the unevenness of the roller surface can be controlled via the coating layer 3, and therefore exists in a dispersed state in the coating layer 3 regardless of the provision of the unevenness on the roller surface. It is possible to design the slidability of the silicone fine particles more effectively. The average particle size of such an organic filler is preferably larger than the primary average particle size of the silicone fine particles, and the organic filler that is less likely to aggregate than the modified silicone fine particles according to the present invention is It is possible to control the unevenness, and even if the silicone fine particles having a small particle size are aggregated, the roller surface unevenness is not affected, and by being present in a highly dispersed state on the roller surface, slidability can be imparted to the roller surface. It becomes possible.

Examples of such organic fillers include urethane-based, acrylic-based, methacrylic-based, and styrene-based. However, when wear resistance is required, urethane-based fillers are preferable, and toner transport amount When high controllability is required, an acrylic filler capable of narrowly controlling the particle size distribution is preferable.
(Coating layer forming method)
As a method for forming the coating layer 3 according to the present invention, for example, the resin composition constituting the coating layer is once used as a solvent on the outer peripheral surface of the elastic layer 2 or the intermediate layer 4 formed around the conductive support member. To obtain a coating layer solution, which is applied to a predetermined thickness using a method such as spray coating, dip coating, and roll coating, and dried and cured at a predetermined temperature to form a coating layer. A method etc. can be illustrated. Specifically, the elastic layer 2 by spraying or dipping a solution in which the components (A), (B), (C), and other additives are dissolved in a solvent to obtain a solid content of 3 to 20%. Or the method of apply | coating on the outer peripheral surface of the intermediate | middle layer 4 is a method which is simple and can be used preferably. In such a spraying method and a method such as a dip method, the thickness of the coating layer can be easily adjusted to the above-mentioned range by repeating spraying and / or dip several times, and preferably, Moreover, in order to improve the film property of a coating layer solution, you may add various additives, such as a leveling agent, to a coating layer solution as needed.

Here, prior to the application, in order to improve the adhesion between the coating layer 3 and the elastic layer 2 or the intermediate layer 4, the surface of the elastic layer 2 or the intermediate layer 4 is subjected to a primer treatment, and then the coating layer. 3 is preferably formed. As a primer that can be used for this treatment, any primer containing various coupling agents or epoxy compounds can be used. It goes without saying that such a primer treatment can also be applied to the improvement of the adhesive layer between the elastic layer 2 and the intermediate layer 4.
(Solvent for coating layer coating)
In this case, the solvent for coating the coating layer to be used is not particularly limited as long as the (A) thermoplastic resin which is the main component of the coating layer to be used is compatible, but preferably, for example, toluene, Examples include xylene, hexane, methyl ethyl ketone, butyl acetate, ethyl acetate, N, N-dimethylformamide, isopropanol, and water.
(Coating layer drying temperature)
Next, the coating layer 3 applied on the outer peripheral surface of the elastic layer 2 or the intermediate layer 4 in this way is dried. Although the drying temperature at this time depends on the relationship with the boiling point of the coating layer coating solvent, generally the coating layer 4 is sufficiently dried and the elastic layer and the coating layer are not deteriorated. In order to make it, 70-200 degreeC is preferable.

  Hereinafter, the present invention will be described in detail by way of examples and comparative examples.

  In these examples and comparative examples, a common conductive support member 1 described below is formed by using a common elastic layer 2 as a raw material, and corresponds to each of the examples and comparative examples. The coating layer 3 was formed under the conditions to produce conductive rollers, and these rollers were evaluated as electrophotographic elastic rollers and electrophotographic conductive rollers.

  That is, as the conductive support member 1, a SUM material having a length of 248 mm and an outer diameter of 8 mmφ and having a surface plated with Ni (steel material with improved free-cutting property compared to general steel) is used. The surface of each was primed and then an elastic layer was formed around it.

At that time, the following (D), (E), (F), and a storage stability imparting agent were used as raw materials for the elastic layer 3.
(D) As an organic polymer, 500 g of allyl-terminated polyoxypropylene (trade name Kaneka Silyl ACS003, manufactured by Kaneka Corporation).
(E) Polyorganohydrogensiloxane (trade name CR100, manufactured by Kaneka Corporation): 16 g.
(F) Bis (1,3-divinyl-1,1,3,3-tetramethyldisiloxane) platinum complex catalyst (platinum content 3 wt%, xylene solution): 0.30 g.
(G) Carbon black (product name “3030B”, manufactured by Mitsubishi Chemical) as a conductivity-imparting agent: 70 g.

  Dimethyl maleate: 0.20 g as a storage stability improver.

  Specifically, these (D), (E), (F) and a storage stability-imparting agent are mixed, defoamed for 120 minutes under a reduced pressure of 10 mmHg or less, and then the curable composition is added to the SUM. The conductive support member 1 made of a material is poured into a mold in which the conductive support member 1 is installed, and then the entire mold is heated at 140 ° C. for 30 minutes to cure the curable composition, and on the outer periphery of the conductive support member 1. An elastic layer 2 having a thickness of 4 mm was formed.

Example 1
On the outer peripheral surface of the elastic layer 2 described above, the coating layer 3 was formed using the following (A), (B), (C), and the coating layer coating solvent as raw materials.
(A) 100 g of a thermoplastic urethane resin (trade name Y-258, manufactured by Dainichi Seika Kogyo) as a thermoplastic resin.
(B) 20 g of silicone fine particles (trade name Charine R-170S, manufactured by Nissin Chemical Industry) modified with acrylic as silicone fine particles modified with a modifying organic compound.
(C) 40 g of carbon black (trade name HS-100, manufactured by Denki Kagaku Kogyo) as a conductivity-imparting agent.

  350 g of N, N′-dimethylformamide as a solvent for coating the coating layer.

  Specifically, the raw material in which the elastic layer 2 is formed on the conductive support member 1 described above is vertically added to a urethane resin solution obtained by mixing these (A), (B), (C), and the coating layer coating solvent. By dipping, this solution is applied to the elastic layer 2 and dried at 140 ° C. for 10 minutes, and then dipped again in the same manner as described above except that the direction of the vertical dip is reversed, Furthermore, the electroconductive roller by which the coating layer 3 was formed on the outer peripheral surface of the elastic layer 2 was produced by drying at 140 degreeC for 30 minutes.

  The conductive roller thus prepared is set as a developing roller in a toner cartridge of a color laser beam printer (LBP-2510, manufactured by Canon), and is 8% at 1% image density in an environment of 23 ° C. and 55% RH. 1,000 sheets were printed. Thereafter, the conductive roller was removed from the toner cartridge, and the toner laminated on the roller surface was sufficiently blown off by air blow. In general, a toner filming roller has toner also adhered to the surface after air blowing, and this is a filming that causes image defects such as vertical stripes and white background fog. It is known that such a filmed toner cannot be removed by air blow because it is fused, but is transferred to the adhesive tape when it is peeled off after the adhesive tape is attached to the roller. In this example, the presence or absence of toner filming was confirmed by visually observing whether or not the toner adhered to the peeled adhesive tape by such taping. In the roller produced in Example 1, toner adhesion was not observed in the taping test after use as such a conductive roller.

(Example 2)
As Example 2, as urethane resin solution of Example 1, in addition to (A), (B), (C) of Example 1 and solvent for coating layer coating, urethane fine particles (trade name) are further used as organic fillers. A conductive roller is formed by the same method as in Example 1 except that C-800, manufactured by Negami Kogyo Co., Ltd., with an average particle diameter of 6 μm, and 20 g are added. As a result of evaluation, toner adhesion was not observed.

(Comparative Example 1)
As Comparative Example 1, as the urethane resin solution of Example 1, (A) and (C) of Example 1, and the coating layer coating solvent were used, that is, Example (B) was not added. When the conductive roller was formed by the same method as in Example 1 and the filming property was evaluated by the same method as in Example 1, toner adhesion was clearly observed.

It is sectional drawing of one Embodiment of the conductive roller of this invention. It is sectional drawing of one Embodiment of the conductive roller of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Conductive support member 2 Elastic layer 3 Covering layer (outermost layer)
4 middle class

Claims (6)

A conductive roller comprising a conductive support member, an elastic layer formed on the outer peripheral surface of the support member, and a coating layer formed on the outer peripheral surface of the elastic layer and exposed on the outermost surface, Is made of a composite material containing the following components (A) to (C) as essential components.
(A) Thermoplastic resin.
(B) Silicone fine particles modified with a modifying organic compound containing at least one element selected from the group consisting of oxygen, nitrogen, and sulfur.
(C) Conductivity imparting agent.   The conductive roller according to claim 1, wherein the component (A) is mainly a thermoplastic urethane resin.   The conductive roller according to claim 1, wherein the modifying organic compound is an acrylic compound and / or an epoxy compound.   The conductive roller according to claim 1, wherein the coating layer further contains an organic filler having an average particle diameter of 1 to 30 μm. The conductive roller according to any one of claims 1 to 4, wherein the elastic layer is a cured product of a curable composition containing the following components (D) to (G) as essential components.
(D) An organic polymer having at least one alkenyl group capable of hydrosilylation reaction in the molecule.
(E) A compound having at least two hydrosilyl groups in the molecule.
(F) Hydrosilylation catalyst.
(G) Conductivity imparting agent.   The electroconductive roller of any one of Claims 1-5 used as a developing roller.

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