WO2019150763A1 - Electroconductive roller and image formation device - Google Patents

Abstract

The purpose of the present invention is to provide an electroconductive roller with which it is possible to suppress image defects, and which has exceptional adhesiveness in a coating film formed on the outer peripheral side of a base layer. In order to achieve this purpose, this electroconductive roller 1 comprises a shaft 2, a base layer 3 formed on the outer peripheral side of the shaft, and a coating film formed on the outer peripheral side of the base layer 3, wherein the electroconductive roller 1 is characterized in that the coating film includes at least a UV-curable resin, and 1-20 parts by mass of at least one selected from the group consisting of N-vinyl amides and N-vinyl imides in relation to 100 parts by mass of the UV-curable resin.

Description

Conductive roller and image forming apparatus

The present invention relates to a conductive roller and an image forming apparatus.

In general, in an electrophotographic image forming apparatus such as a copying machine, a facsimile, or a laser beam printer (LBP), a developing roller, a charging roller, a toner supply roller, a transfer roller, a paper feeding roller, a cleaning roller, and a pressure for fixing. As a roller or the like, a roll-shaped conductive elastic member, that is, a conductive roller is frequently used, and the conductive roller is usually mounted with a shaft member supported by both ends in the length direction, and the shaft member. And an elastic base layer disposed on the outside in the radial direction.
Here, various rubbers and elastomers such as polyurethane are used for the base layer, and the elastic layer can be manufactured by injecting an elastomer raw material into a mold having a desired cavity shape and heat-curing it. .

The conductive roller further forms a coating layer on the surface of the base layer for the purpose of improving the hardness of the roller, controlling chargeability and adhesion to toner, preventing contamination of the photosensitive drum by the elastic layer, and the like. There is a case.
For example, a technique of providing a coating layer made of an ultraviolet curable resin on a base layer is known. However, when an ultraviolet curable resin is used as the coating layer, although the contamination property is improved, curing shrinkage tends to occur in the surface layer when cured by ultraviolet irradiation, distortion occurs between the base layer and the surface layer, and the interlayer adhesion There was a problem that the property and adhesiveness deteriorated.

Therefore, various techniques have been developed to improve the interlayer adhesion between the base layer and the coating layer. For example, in Patent Document 1, the surface layer contains a urethane acrylate oligomer having a large molecular weight (specifically, 6000 or more) and acryloylmorpholine, thereby improving the quality of the coating layer and improving interlayer adhesion. Techniques to be disclosed are disclosed.

JP 2008-106840 A

However, in the technique of Patent Document 1, although interlaminar adhesion is improved by using acryloylmorpholine, there is room for further improvement from the viewpoint of flexibility. It was also conceivable that sufficient pressure contact with this member could not be obtained, resulting in image defects.

Therefore, an object of the present invention is to provide a conductive roller that can suppress image defects and is excellent in adhesion of a coating film formed on the outer peripheral side of a base layer. Another object of the present invention is to provide an image forming apparatus in which the occurrence of image defects is greatly reduced.

In order to solve the above problems, the conductive roller of the present invention is a conductive roller comprising a shaft, a base layer formed on the outer peripheral side of the shaft, and a coating film formed on the outer peripheral side of the base layer. And
The coating film comprises at least an ultraviolet curable resin and at least one selected from the group consisting of N-vinyl amide and N-vinyl imide in an amount of 1 to 20 parts by mass with respect to 100 parts by mass of the ultraviolet curable resin. It is characterized by including.
By providing the above configuration, it is possible to provide a conductive roller that can suppress image defects and is excellent in adhesion of a coating film formed on the outer peripheral side of the base layer.

Here, in the conductive roller of the present invention, it is preferable that the coating film is a surface layer formed on the base layer or an intermediate layer formed between the base layer and the surface layer. This is because the adhesion between the surface layer or intermediate layer of the conductive roller and the base layer can be enhanced.

In the conductive roller of the present invention, the N-vinylamide is preferably at least one selected from the group consisting of N-vinylacetamide, N-vinylpyrrolidone and N-vinyl-ε-caprolactam. This is because better adhesion of the coating film can be obtained.

Furthermore, in the conductive roller of the present invention, the N-vinylimide is preferably N-vinylphthalimide. This is because better adhesion of the coating film can be obtained.

Furthermore, for the conductive roller of the present invention, the coating film preferably contains at least one selected from the group consisting of silica and carbon black, and the total content of the silica and the carbon black is the ultraviolet curing. The amount is more preferably 3 to 15 parts by mass with respect to 100 parts by mass of the conductive resin. This is because the occurrence of image defects can be more reliably suppressed while having excellent coating film adhesion.

The image forming apparatus of the present invention includes the above-described conductive roller of the present invention.
With the above configuration, the occurrence of image defects due to the state of the conductive roller can be greatly reduced.

According to the present invention, it is possible to provide a conductive roller that can suppress image defects and is excellent in adhesion of a coating film formed on the outer peripheral side of the base layer. In addition, according to the present invention, it is possible to provide an image forming apparatus in which the occurrence of image defects is greatly reduced.

(A) is sectional drawing which showed typically one Embodiment of the conductive roller of this invention, (b) showed typically other Embodiment of the conductive roller of this invention. It is sectional drawing. 1 is a partial cross-sectional view schematically illustrating an example of an image forming apparatus.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings as necessary.
Here, FIG. 1 (a) schematically shows one embodiment of the conductive roller of the present invention, and FIG. 1 (b) shows another embodiment of the conductive roller of the present invention. This is schematically shown. FIG. 2 is a cross-sectional view schematically showing one embodiment of the conductive roller of the present invention.

<Conductive roller>
As shown in FIGS. 1 (a) and 1 (b), the conductive roller 1 of the present embodiment includes at least a base layer 3 and a coating film (FIG. 1 (a)) on the outer peripheral side of the shaft 2. Is a conductive roller 1 having a surface layer 4 and an intermediate layer 5) in FIG.

Here, as an example of the conductive roller of the present invention, specifically, a charging roller that uniformly charges an image carrier such as a photoconductor, a developing roller that carries and conveys a developer and supplies the developer to the image carrier, Developer supply roller for supplying developer while charging the developer roller, fixing roller for fixing the developer image transferred to a recording medium such as recording paper, cleaning roller for removing the developer adhering to the image carrier, etc. Etc.
Among these, the conductive roller of the present invention is preferably used as a developing roller. This is because the developing roller is a member that is particularly required to be able to suppress a decrease in print density due to a deterioration in toner conveyance performance, and thus can effectively benefit from the solution of the problem of the present invention.

Hereinafter, each component of the conductive roller of this embodiment will be described.
(Base layer)
As shown in FIGS. 1A and 1B, the base layer 3 constituting the conductive roller 1 of the present embodiment is a layer positioned at the lowermost part of the conductive roller 1 (adjacent to the shaft 2).

The material constituting the base layer is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include polyurethane resin, rubber elastic body, polyamide resin, polyester resin, polyimide resin, silicone resin, acrylic resin, and polyfluoride. Vinylidene fluoride resin, polyvinyl butyral resin, ethylene-tetrafluoroethylene copolymer resin, melamine resin, fluorine resin, epoxy resin, polycarbonate resin, polyvinyl alcohol resin, cellulose resin, polyvinylidene chloride resin, polyvinyl chloride resin, polyethylene resin, And ethylene-vinyl acetate copolymer resin. These may be used individually by 1 type and may use 2 or more types together. Among these, a polyurethane resin is preferable in that good flexibility can be realized.

There is no restriction | limiting in particular as said polyurethane resin as a polyurethane resin, According to the objective, it can select suitably. For example, a polyester-type urethane resin, a polyether-type urethane resin, a polycarbonate-type urethane resin, etc. are mentioned. These may be used individually by 1 type and may use 2 or more types together.
Among these, polyether-based urethane resins are preferable in that the resistance value of the resin is low and hydrolysis hardly occurs. Moreover, when it is a polyurethane resin having a (meth) acrylate group, it can be cured by ultraviolet irradiation. In particular, a polyurethane in which a (meth) acrylate group is introduced at the end of the polyurethane is preferable from the viewpoint of excellent ultraviolet curing efficiency.

Here, the said base layer is formed from the composition for base layers.
The composition for the base layer is not particularly limited as long as it is a composition capable of forming the base layer, and can be appropriately selected according to the purpose.
When forming the base layer of the polyurethane resin, the base layer composition preferably includes components such as a polyol, an isocyanate, a urethane bond catalyst, a solvent, and a filler. Moreover, when forming the base layer which consists of the said polyurethane foam, it is preferable that a foam stabilizer is further included.
In addition to the above-mentioned components, the composition for the base layer may include an ionic conductive agent, a plasticizer, a softening agent, a tackifier, an anti-tacking agent, a separating agent, a release agent, an extender, a colorant, and a crosslinking agent as necessary. An agent, a vulcanizing agent, a polymerization inhibitor, and the like may be included.

In addition, there is no restriction | limiting in particular as said polyol, According to the objective, it can select suitably. For example, polyether polyol, polyester polyol, polytetramethylene glycol, polybutadiene polyol, alkylene oxide modified polybutadiene polyol, polyisoprene polyol, and the like can be mentioned. These may be used individually by 1 type and may use 2 or more types together.
Among these, polyether polyol is preferable in terms of reducing the flexibility and permanent compression strain of the resin.

Moreover, there is no restriction | limiting in particular as said isocyanate, According to the objective, it can select suitably. For example, tolylene diisocyanate (TDI), prepolymerized tolylene diisocyanate (prepolymerized TDI), diphenylmethane diisocyanate (MDI), crude diphenylmethane diisocyanate (crude MDI), isophorone diisocyanate (IPDI), hydrogenated diphenylmethane diisocyanate, hydrogenated triphenyl Examples thereof include range isocyanate, hexamethylene diisocyanate (HDI); these isocyanurate-modified products, carbodiimide-modified products, glycol-modified products, and the like. These may be used individually by 1 type and may use 2 or more types together.
Among these, prepolymerized tolylene diisocyanate (prepolymerized TDI) is preferable in that it has a high urethane reaction activity and can easily improve the elasticity of the base layer and thus the conductive roller.

There is no restriction | limiting in particular as said urethane bond catalyst, According to the objective, it can select suitably. For example, dibutyltin dilaurate, dioctyltin acetate, dioctyltin bis (ethylmalate), dibutyltin bis (oleylmalate), dibutyltin diacetate, dibutyltin thiocarboxylate, dibutyltin dimaleate, dioctyltin thiocarboxylate, tin octenoate , Monobutyltin oxide, and the like. These may be used individually by 1 type and may use 2 or more types together.
Among these, dibutyltin dilaurate is preferable in terms of high catalytic activity.

There is no restriction | limiting in particular as said foam stabilizer, According to the objective, it can select suitably. For example, a silicone type foam stabilizer, an ionic surfactant, a nonionic surfactant, etc. are mentioned. These may be used individually by 1 type and may use 2 or more types together. Among these, a silicone type foam stabilizer is preferable in that the foam uniformity of the foam is good.
Moreover, it is preferable that the said silicone type foam stabilizer has a functional group. The functional group of the silicone foam stabilizer is not particularly limited and may be appropriately selected depending on the intended purpose. For example, OH (hydroxy acid) group, thiol group, amino group, imino group, nitro group, nitroso Group, carboxyl group, acryloyl group, alkyl group, alkenyl group, alkoxy group, and the like. These may be used individually by 1 type and may use 2 or more types together. Among these, when an isocyanate is contained in the composition for an adhesive layer described below, the OH (hydric acid) group has an urethane bond with an OH (hydric acid) group derived from the silicone foam stabilizer of the base layer. Since it forms, it is preferable at the point which can improve the adhesiveness between a base layer and an adhesive layer more. If the moisture-curing adhesive described below contains MDI having two or more isocyanate groups, MDI has high electron withdrawing properties and is easy to chemically react with the foam stabilizer OH, resulting in high reaction efficiency and adhesion. Can be particularly improved.

The solvent is not particularly limited and may be appropriately selected depending on the purpose. For example, alcohols such as methanol, ethanol, isopropyl alcohol; butyl acetate; dimethyl sulfone; dimethyl sulfoxide; tetrahydrofuran; dioxane; toluene; xylene; These may be used individually by 1 type and may use 2 or more types together. Of these, butyl acetate is preferred because of its high volatilization rate.

In addition, when forming a base layer with the said composition for base layers, the electroconductive roller of this invention can form a base layer by apply | coating the said composition for base layers to the outer surface of a shaft, and then irradiating with an ultraviolet-ray. Therefore, the roller of the present invention does not require a large amount of heat energy and can be manufactured in a short time. Moreover, since a curing furnace or the like is not required for production, a large amount of equipment costs are not required. Examples of the method for applying the layer forming raw material to the outer surface of the shaft or the surface of the base layer include a spray method, a roll coater method, a dipping method, and a die coating method. Examples of the light source used for ultraviolet irradiation include a mercury lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a metal halide lamp, and a xenon lamp. The conditions for ultraviolet irradiation are appropriately selected according to the components, composition, coating amount, and the like contained in the layer forming raw material, and the irradiation intensity and the integrated light amount may be adjusted as appropriate.
Moreover, when forming the said base layer with a polyurethane foam, a base layer can be formed by carry | supporting the composition for base layers containing a polyurethane foam directly on the radial direction outer side of a shaft, for example.

(Coating film (surface layer, intermediate layer))
The electroconductive roller 1 of this embodiment is provided with the coating film formed in the outer peripheral side of the base layer mentioned above, as shown to Fig.1 (a) and (b).
Here, the coating film in the present invention refers to a layer formed directly on the base layer 3. As shown in FIG. 1A, when the surface layer 4 is directly formed on the base layer 3 in the conductive roller 1, the surface layer 4 corresponds to the coating film, and as shown in FIG. When the intermediate layer 5 is formed between the base layer 3 and the surface layer 4, the intermediate layer 5 corresponds to the coating film. Although not shown, when there is a further intervening layer between the intermediate layer 5 and the surface layer, the intervening layer corresponds to the coating film.

In the present invention, the coating film is selected from the group consisting of at least an ultraviolet curable resin and 1 to 20 parts by mass of N-vinylamide and N-vinylimide with respect to 100 parts by mass of the ultraviolet curable resin. And at least one kind.
By containing at least one selected from the group consisting of N-vinylamide and N-vinylimide in the coating film, the adhesion to the surface layer of the coating film containing an ultraviolet curable resin can be greatly improved. However, when the content of N-vinylamide and / or N-vinylimide is too large, the coating film is cured, damages the toner, and image defects such as streaks may occur. Therefore, when at least one content selected from the group consisting of N-vinyl amide and N-vinyl imide falls within the range of 1 to 20 parts by mass with respect to 100 parts by mass of the ultraviolet curable resin, the occurrence of image defects is prevented. While suppressing, the adhesiveness of the coating film can be improved.

The coating film may be a layer formed directly on the base layer 3, but the adhesiveness with the base layer 3 can be improved, and the image performance can be further improved. 1 is a surface layer 4 formed on the base layer 3 as shown in FIG. 1A, or an intermediate layer formed between the base layer 3 and the surface layer 4 as shown in FIG. 5 is preferable.

Here, about the said ultraviolet curable resin, it is resin used as the base material of the said coating film, A well-known ultraviolet curable resin, such as a polyurethane resin, an acrylic resin, a vinyl ester resin, an epoxy resin, can be used.
Among these UV curable resins, polyurethane resins are used because they can increase the adhesion and flexibility of the coating film, can be cured quickly and can shorten the working time, and can be cured at low temperatures. Is preferably used.

There is no restriction | limiting in particular as said polyurethane resin as a polyurethane resin, According to the objective, it can select suitably. For example, a polyester-type urethane resin, a polyether-type urethane resin, a polycarbonate-type urethane resin, etc. are mentioned. These may be used individually by 1 type and may use 2 or more types together.
Among these, polyether-based urethane resins are preferable in that the resistance value of the resin is low and hydrolysis hardly occurs. Moreover, when it is a polyurethane resin having a (meth) acrylate group, it can be cured by ultraviolet irradiation. In particular, a polyurethane in which a (meth) acrylate group is introduced at the end of the polyurethane is preferable from the viewpoint of excellent ultraviolet curing efficiency.

Here, the coating film is formed from a coating film composition.
The coating film composition includes, in addition to at least one selected from the group consisting of N-vinylamide and N-vinylimide, and an ultraviolet curable resin, a (meth) acrylate monomer, a silicone additive, a fluorine additive, a polyol, Isocyanate, a solvent, a photoinitiator, etc. can be included.

At least one selected from the group consisting of N-vinylamide and N-vinylimide contained in the coating film is not particularly limited except the content thereof, and known N-vinylamide and N-vinylimide are used. be able to.
With respect to at least one content selected from the group consisting of N-vinylamide and N-vinylimide contained in the coating film, image defects can be suppressed and adhesion to the base layer can be improved. From 1 to 20 parts by mass with respect to 100 parts by mass of the ultraviolet curable resin. When the content is less than 1 part by mass with respect to 100 parts by mass of the ultraviolet curable resin, sufficient adhesion with the base layer 3 cannot be obtained, while the content is 100 masses of the ultraviolet curable resin. This is because if the amount exceeds 20 parts by mass with respect to the part, the coating film is cured, so that an image defect may occur. Further, from the same viewpoint, the content of at least one selected from the group consisting of the N-vinylamide and the N-vinylimide is preferably 1 to 15 parts by mass, and preferably 2 to 8 parts by mass. Is more preferable.
Note that at least one content selected from the group consisting of N-vinylamide and N-vinylimide contained in the coating film was blended in the coating composition, not in the cured coating film. The content (parts by mass) with respect to 100 parts by mass of at least one ultraviolet curable resin component selected from the group consisting of N-vinylamide and N-vinylimide.

Here, the type of the N-vinylamide is not particularly limited, and a known N-vinylamide can be used. For example, N-vinylacetamide, N-vinylpyrrolidone, N-vinyl-ε-caprolactam, N-vinylformamide, N-vinylpropionamide, N-vinylbutyramide, N? Examples include vinyl barrel amide. Among these, the N-vinylamide is selected from the group consisting of N-vinylacetamide, N-vinylpyrrolidone and N-vinyl-ε-caprolactam from the standpoint that better adhesion to the base layer can be obtained. At least one kind is preferred.

The type of the N-vinylimide is not particularly limited, and a known N-vinylimide can be used. Examples thereof include N-vinylphthalimide, N-vinylmaleimide, N-vinylsuccinimide, N-vinylcyclopentanecarboximide, N-vinylnaphthalimide and the like. Among these, the N-vinyl imide is preferably N-vinyl phthalimide from the viewpoint of obtaining better adhesiveness with the base layer.

The polyol is not particularly limited as long as it can form the above-described ultraviolet curable resin, and can be appropriately selected according to the purpose.
Examples of the polyol include polyether polyol, polyester polyol, polytetramethylene glycol, polybutadiene polyol, alkylene oxide-modified polybutadiene polyol, and polyisoprene polyol. These may be used individually by 1 type and may use 2 or more types together.

The (meth) acrylate monomer is not particularly limited and can be appropriately selected depending on the purpose. For example, acryloylmorpholine, N, N-diethylaminoethyl methacrylate, isobornyl acrylate, phenoxyethyl acrylate, and the like can be given from the viewpoint that better adhesion to the base layer can be obtained. These may be used individually by 1 type and may use 2 or more types together.

Further, as the (meth) acrylate monomer, for example, at least one selected from the group consisting of (meth) acrylate monomers containing silicon and fluorine can be used in order to control the friction coefficient and chemical resistance.

Moreover, there is no restriction | limiting in particular also about the said isocyanate, According to the objective, it can select suitably. For example, tolylene diisocyanate (TDI), prepolymerized tolylene diisocyanate (prepolymerized TDI), diphenylmethane diisocyanate (MDI), crude diphenylmethane diisocyanate (crude MDI), isophorone diisocyanate (IPDI), hydrogenated diphenylmethane diisocyanate, hydrogenated triphenyl Examples include diisocyanate, hexamethylene diisocyanate (HDI), these isocyanurate-modified products, carbodiimide-modified products, and glycol-modified products. These may be used individually by 1 type and may use 2 or more types together.
Among these, isophorone diisocyanate is advantageous in that the viscosity can be easily adjusted in the production process, the flexibility of the base layer can be easily secured, and the like.

Examples of the photopolymerization initiator contained in the coating film composition include 4-dimethylaminobenzoic acid, 4-dimethylaminobenzoic acid ester, 2,2-dimethoxy-2-phenylacetophenone, acetophenone diethyl ketal, and alkoxyacetophenone. Benzyldimethyl ketal, benzophenone and 3,3-dimethyl-4-methoxybenzophenone, 4,4-dimethoxybenzophenone, benzophenone derivatives such as 4,4-diaminobenzophenone, alkyl benzoylbenzoate, bis (4-dialkylaminophenyl) ketone Benzyl derivatives such as benzyl and benzylmethyl ketal, benzoin derivatives such as benzoin and benzoin isobutyl ether, benzoin isopropyl ether, 2-hydroxy-2-methylpropiofe , 1-hydroxycyclohexyl phenyl ketone, xanthone, thioxanthone and thioxanthone derivatives, fluorene, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide Bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1,2-benzyl-2-dimethylamino-1- (Morpholinophenyl) -butanone-1 and the like can be used. These photoinitiators may be used individually by 1 type, and may use 2 or more types together.

Furthermore, the coating film composition preferably contains at least one selected from the group consisting of silica and carbon black in addition to the above-described components. By containing at least one selected from the group consisting of silica and carbon black as a filler in the coating film, the paintability of the coating film is improved, and as a result, the effect of suppressing image defects can be further enhanced. .

Furthermore, the total content of the silica and the carbon black is 100% by mass of the ultraviolet curable resin from the viewpoint that a more excellent image defect suppressing effect can be obtained while maintaining the adhesion of the coating film at a high level. The amount is preferably 3 to 15 parts by mass with respect to parts. By making the total content 3 parts by mass or more with respect to 100 parts by mass of the ultraviolet curable resin, it is possible to realize a more excellent image defect suppression effect, while the total content is determined to be the ultraviolet curable resin 100. By making the amount 15 parts by mass or less with respect to the part by mass, the adhesiveness of the coating film is not adversely affected. From the same viewpoint, the total content of the silica and the carbon black is preferably 3 to 10 parts by mass, more preferably 3 to 8 parts by mass with respect to 100 parts by mass of the ultraviolet curable resin. .
In addition, about content of the said silica and the said carbon black, it is content with respect to 100 mass parts of ultraviolet curable resin components of the silica and carbon black mix | blended in the said composition for coating films instead of the coating film after hardening. (Part by mass).

In addition, the said composition for coating films can also contain another component as needed in addition to each component mentioned above. There is no restriction | limiting in particular about another component, According to the objective, it can select suitably. Other components include, for example, conductive agents, elastomers other than ultraviolet curable resins, catalysts, foam stabilizers, fillers, fine particles, peptizers, foaming agents, plasticizers, softeners, tackifiers, and anti-tacking agents. , Separating agents, mold release agents, extenders, colorants, vulcanizing agents, polymerization inhibitors, and the like. These may be used individually by 1 type and may use 2 or more types together.

The conductive agent has an effect of imparting conductivity to the coating film. Such a conductive agent is preferably one that can transmit ultraviolet rays, preferably an ionic conductive agent or a transparent electronic conductive agent, and particularly preferably an ionic conductive agent. Since the ionic conductive agent dissolves in the urethane acrylate oligomer and has transparency, when the ionic conductive agent is used as the conductive agent, even if the layer forming raw material is applied thickly on the shaft, the ultraviolet ray is sufficiently applied. It reaches the inside of the film, and the layer forming raw material can be sufficiently cured. Here, as the ionic conductive agent, tetraethylammonium, tetrabutylammonium, dodecyltrimethylammonium, hexadecyltrimethylammonium, benzyltrimethylammonium, modified fatty acid dimethylethylammonium and the like perchlorate, chlorate, hydrochloride, bromate Ammonium salts such as salts, iodates, borofluorides, sulfates, ethyl sulfates, carboxylates, sulfonates; alkaline metals such as lithium, sodium, potassium, calcium, magnesium, alkaline earth metals Examples include perchlorate, chlorate, hydrochloride, bromate, iodate, borofluoride, sulfate, trifluoromethyl sulfate, and sulfonate. In addition, transparent electronic conductive agents include fine particles of metal oxides such as ITO, tin oxide, titanium oxide, and zinc oxide; fine particles of metals such as nickel, copper, silver, and germanium: conductive titanium oxide whiskers, conductive titanium Examples include conductive whiskers such as barium acid whiskers. Further, as an electronic conductive agent, conductive carbon such as ketjen black and acetylene black, carbon black for rubber such as SAF, ISAF, HAF, FEF, GPF, SRF, FT and MT, color carbon subjected to oxidation treatment, etc. Black, pyrolytic carbon black, natural graphite, artificial graphite or the like may be used. These electrically conductive agents may be used individually by 1 type, and may use 2 or more types together.

An elastomer other than the ultraviolet curable resin can be appropriately contained according to the purpose. Examples of the elastomer include silicone, ethylene-propylene-diene rubber (EPDM), acrylonitrile-butadiene rubber (NBR), natural rubber (NR), styrene-butadiene rubber (SBR), butadiene rubber (BR), and isoprene rubber (IR). ), Polynorbornene rubber, butyl rubber (IIR), chloroprene rubber (CR), acrylic rubber, epichlorohydrin rubber (ECO), ethylene-vinyl acetate copolymer (EVA); and mixtures thereof. These may be used individually by 1 type and may use 2 or more types together.

Examples of the catalyst include organic tin compounds such as dibutyltin dilaurate, dibutyltin diacetate, dibutyltin thiocarboxylate, dibutyltin dimaleate, dioctyltin thiocarboxylate, tin octenoate, and monobutyltin oxide; inorganic such as stannous chloride Tin compounds; organic lead compounds such as lead octenoate; monoamines such as triethylamine and dimethylcyclohexylamine; diamines such as tetramethylethylenediamine, tetramethylpropanediamine and tetramethylhexanediamine; pentamethyldiethylenetriamine, pentamethyldipropylenetriamine; Triamines such as tetramethylguanidine; triethylenediamine, dimethylpiperazine, methylethylpiperazine, methylmorpholine, dimethylamine Cyclic amines such as noethylmorpholine, dimethylimidazole, pyridine; alcohol amines such as dimethylaminoethanol, dimethylaminoethoxyethanol, trimethylaminoethylethanolamine, methylhydroxyethylpiperazine, hydroxyethylmorpholine; bis (dimethylaminoethyl) ether Ether amines such as ethylene glycol bis (dimethyl) aminopropyl ether; organic sulfonic acids such as p-toluenesulfonic acid, methanesulfonic acid and fluorosulfuric acid; inorganic acids such as sulfuric acid, phosphoric acid and perchloric acid; sodium alcoholate; Bases such as lithium hydroxide, aluminum alcoholate, sodium hydroxide; titanium compounds such as tetrabutyl titanate, tetraethyl titanate, tetraisopropyl titanate; Bismuth compounds; quaternary ammonium salts, and the like. Of these catalysts, organotin compounds are preferred. These catalysts may be used individually by 1 type, and may be used in combination of 2 or more type.
The amount of the catalyst used is preferably in the range of 0.001 to 2.0 parts by mass with respect to 100 parts by mass of the polyol.

There is no restriction | limiting in particular as said foam stabilizer, According to the objective, it can select suitably. For example, a silicone type foam stabilizer, an ionic surfactant, a nonionic surfactant, etc. are mentioned. These foam stabilizers may be used individually by 1 type, and may use 2 or more types together.
Of the above-mentioned foam stabilizers, silicone foam stabilizers are preferable in that the foam uniformity of the foam is good.

(shaft)
The conductive roller of the present invention includes a shaft 2 as shown in FIGS. The material constituting the shaft 2 is not particularly limited as long as it has good conductivity. For example, it can be a shaft made of metal, a shaft made of a highly rigid resin base material, or a combination thereof. Further, it may be a metal or hollow cylinder made of a highly rigid resin hollowed inside.

In addition, when using highly rigid resin for the said shaft, it is preferable to ensure sufficient electroconductivity by adding and disperse | distributing a electrically conductive agent to highly rigid resin. Here, as the conductive agent dispersed in the high-rigidity resin, carbon black powder, graphite powder, carbon fiber, metal powder such as aluminum, copper and nickel, metal oxide powder such as tin oxide, titanium oxide and zinc oxide, conductive A powdery conductive agent such as conductive glass powder is preferred. These electrically conductive agents may be used individually by 1 type, and may be used in combination of 2 or more type. The blending amount of the conductive agent is not particularly limited, but is preferably in the range of 5 to 40% by mass, and more preferably in the range of 5 to 20% by mass with respect to the entire highly rigid resin.

The material of the metal shaft or metal cylinder includes iron, stainless steel, aluminum, etc., and these may be plated with zinc or nickel. The material of the high-rigidity resin base material 1B includes polyacetal, polyamide 6, polyamide 6 and 6, polyamide 12, polyamide 4 and 6, polyamide 6 and 10, polyamide 6 and 12, polyamide 11, polyamide MXD6, poly Butylene terephthalate, polyphenylene oxide, polyphenylene sulfide, polyethersulfone, polycarbonate, polyimide, polyamideimide, polyetherimide, polysulfone, polyetheretherketone, polyethylene terephthalate, polyarylate, liquid crystal polymer, polytetrafluoroethylene, polypropylene, ABS resin, Examples include polystyrene, polyethylene, melamine resin, phenol resin, and silicone resin. Among these, polyacetal, polyamide 6/6, polyamide MXD6, polyamide 6/12, polybutylene terephthalate, polyphenylene ether, polyphenylene sulfide, and polycarbonate are preferable. These highly rigid resins may be used alone or in combination of two or more.

<Image forming apparatus>
The image forming apparatus of the present invention includes the above-described conductive roller of the present invention.
By providing the conductive roller of the present invention in the image forming apparatus, it is possible to suppress the occurrence of image defects due to the conductive roller.

Here, FIG. 2 schematically shows an embodiment of the image forming apparatus of the present invention. In the image forming apparatus of the present embodiment, the conductive roller 1 of the present invention is used as the developing roller 16. Used. In the image forming apparatus according to the present embodiment, the photosensitive member 11 holding the electrostatic latent image, the charging roller 12 positioned near the photosensitive member 11 (upward in the drawing) to charge the photosensitive member 11, and the toner storage The toner supply roller 13 for supplying the toner 15 in the section 14, the developing roller 16 disposed between the toner supply roller 13 and the photosensitive member 11, and the vicinity of the developing roller 16 (upward in the drawing) are provided. A cleaning blade 17, a transfer roller 18 located in the vicinity (downward in the drawing) of the photoconductor 11, and a cleaning roller 19 disposed adjacent to the photoconductor 11.
Note that the image forming apparatus of this embodiment can further include a known component (not shown) that is normally used in the image forming apparatus.

In the image forming apparatus shown in FIG. 2, first, the charging roller 12 is brought into contact with the photosensitive member 11, and a voltage is applied between the photosensitive member 11 and the charging roller 12 to charge the photosensitive member 11 to a constant potential. Thereafter, an electrostatic latent image is formed on the photoconductor 11 by an exposure machine (not shown). Next, the photoreceptor 11, the toner supply roller 13, and the developing roller 16 rotate in the direction of the arrow in the drawing, so that the toner 15 on the toner supply roller 13 is sent to the photoreceptor 11 through the developing roller 16. It is done. The toner 15 on the developing roller 16 is adjusted to a uniform thin layer by the cleaning blade 17 and rotates while the developing roller 16 and the photoconductor 11 are in contact with each other, so that the toner 15 is transferred from the developing roller 16 to the photoconductor 11. The latent image is visualized by adhering to the electrostatic latent image. The toner 15 attached to the latent image is transferred to a recording medium such as paper by the transfer roller 18, and the toner 15 remaining on the photoconductor 11 after the transfer is removed by the cleaning roller 19.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples.

<Samples 1-17>
Each sample of the developing roller was produced under the conditions described below.

(Preparation of base layer)
20g Sanix FA-951 (manufactured by Sanyo Chemical Industries) as a polyol, 50g Kuraray polyol F-510 (manufacturer: Kuraray) as a polyol, and Kuraray polyol F-1010 (Kuraray Co., Ltd.) as a polyol )) 20 g, a predetermined amount of prepolymerized TDI as an isocyanate (Asahi Glass Co., Ltd.) (isocyanate group% = 7%), (meth) acrylate ("Light Ester HO-A", Kyoeisha Chemical Co., Ltd. )) 4g, Neostan U-100 (manufactured by Nitto Kasei Co., Ltd.) 0.1g as a catalyst, and a predetermined amount of SF-2937F (manufactured by Toray Dow Corning Co., Ltd.) as a foam stabilizer in a container The composition for base layer was prepared. Here, the prepolymerized TDI as the isocyanate was used in the blending so that the INDEX ratio (number of moles of isocyanate group / number of moles of hydroxyl group) was 1.1.
The prepared base layer composition was stirred at 2000 rpm for 5 minutes using a disper mixer. The above-mentioned mixture for preparing the base layer was poured into a 200 mm × 200 mm × 2 mm mold whose inner surface was coated with fluorine. The cured urethane base layer was removed from the mold by heating at 120 ° C. for 30 minutes using an oven.

(Production of surface layer)
The ingredients listed in Table 1 were blended and stirred at 2000 rpm for 5 minutes using a disper mixer to prepare a surface layer composition.
Thereafter, a 0.1 mm-thick metal spacer was attached to the base layer produced by the above method, and the surface layer composition was poured. Thereafter, a polyethylene terephthalate film (PET film) and a Pyrex (registered trademark) glass having a thickness of 5 mm were placed on the upper part of the surface layer composition. Thereafter, ultraviolet rays were irradiated using a D bulb of a 6 inch UV lamp-conveyor system (FusionUV). At that time, the conveyor speed was 2 cm / sec. The peak intensity of the irradiated ultraviolet light (365 nm) was 1584 mW / cm, and the integrated light amount was 1086 mJ / cm ² .
A developing roller serving as a sample having a base layer and a surface layer (coating layer) was obtained by curing the surface layer composition by ultraviolet irradiation.

<Evaluation>
The following evaluation was performed for each sample of the produced developing roller.

(1) Elastic modulus of the roller For each sample of the developing roller, the deformation amount when a load of 0.385 mN is applied is measured using a hardness meter “WIN-HCU” manufactured by Fischer Instruments. The rate (MPa) was calculated.
The obtained elastic modulus is shown in Table 1.

(2) Adhesive strength of coating film A sheet sample (test sample) of 1 mm × 1 mm was cut out from each sample of the developing roller. Then, cut the test sample between the surface layer and the base layer with a cutter knife, and using EZ-TEST (manufactured by Shimadzu Corporation), the adhesive strength between the base layer and the surface layer by 180 degree peeling method Was measured. The peel rate was 10 mm / min, the average value of the peak test forces of the five test samples was calculated, and this was used as the adhesive strength (N).
The obtained adhesive strength is shown in Table 1. Note that the larger the value is, the higher the adhesive force is, and an adhesive strength of 2N or more is suitable for ensuring the durability of the conductive roller.

(3) Printed image and roller condition (3-1) Each sample of the developing roller is attached to a printing device ("HL-2240D" manufactured by Brother Industries, Ltd.) and temperature is 10 ° C and humidity is 15% RH. Below, 2600 black images with 1% density were printed. Thereafter, the printed image was observed and evaluated according to the following criteria. The evaluation results are shown in Table 1.
○: Reflection density of black image is 1.30 or more and there is no image defect such as streak ×: Reflection density of black image is less than 1.30, or image defect such as streak occurs in black image (3-2) For each sample of the developing roller, the state of the developing roller after printing 2600 black images as described above was observed and evaluated according to the following criteria. The evaluation results are shown in Table 1.
○: No abnormality in the developing roller ×: Peeling or cracking occurred on part of the surface layer of the developing roller

* 1: About the ultraviolet curable resin 1, it prepared as follows.
As the polyol, Sannics PP-2000 (molecular weight 2000) of both-end hydroxyl group polypropylene diol (manufactured by Sanyo Chemical Industries, Ltd.) is blended, and as the isocyanate, isophorone diisocyanate (manufactured by Evonik Japan Co., Ltd.) is used. 22 parts by mass for 100 parts by mass of polyol, 0.05 part by mass of tin catalyst U-810 as a catalyst for urethane reaction, and 2-hydroxyethyl acrylate: light ester HOA (N) for cap of terminal isocyanate 12 parts by mass of 100 parts by mass of the polyol (manufactured by Kyoeisha Chemical Co., Ltd.) was blended to prepare an ether-based urethane acrylate oligomer. The isocyanate index is 2.0.
* 2: The ultraviolet curable resin 2 was prepared as follows.
As a polyol, Plaxel 220N (molecular weight 2000) (made by Daicel Corporation) of both terminal hydroxyl group polycapracton diol is blended, and as a isocyanate, isophorone diisocyanate (manufactured by Evonik Japan Co., Ltd.) is added to 100 parts by mass of the polyol. 22 parts by mass, 0.05 parts by mass of tin catalyst U-810 as a urethane reaction catalyst, and 2-hydroxyethyl acrylate: light ester HOA (N) (Kyoeisha Chemical Co., Ltd.) 12 parts by mass with respect to 100 parts by mass of the polyol to prepare an ester urethane acrylate oligomer. The isocyanate index is 2.0.
* 3: The ultraviolet curable resin 3 was prepared as follows.
As a polyol, Duranol T5652 (molecular weight 2000) (both Asahi Kasei Chemicals Co., Ltd.) of a hydroxyl group polycarbonate diol at both ends is blended, and isophorone diisocyanate (Evonik Japan Co., Ltd.) is added as an isocyanate to 100 parts by mass of the polyol. 22 parts by mass, 0.05 parts by mass of tin catalyst U-810 as a catalyst for urethane reaction, and 2-hydroxyethyl acrylate: light ester HOA (N) (Kyoeisha Chemical Co., Ltd.) for the isocyanate cap at the end 12) parts by mass with respect to 100 parts by mass of the polyol to prepare a carbonate-based urethane acrylate oligomer. The isocyanate index is 2.0.
* 4: The ultraviolet curable resin 4 was prepared as follows.
GI-2000 (molecular weight 2100) (both Nippon Soda Co., Ltd.) of hydroxyl-terminated hydroxylated polybutadiene is blended as the polyol, and isophorone diisocyanate (Evonik Japan Co., Ltd.) is used as the isocyanate. 21 parts by mass per part, 0.05 parts by mass of tin catalyst U-810 as a urethane reaction catalyst, and 2-hydroxyethyl acrylate: light ester HOA (N) (Kyoeisha Chemical) 12 parts by mass with respect to 100 parts by mass of the polyol was prepared to prepare a butadiene-based urethane acrylate oligomer.
* 5: N-vinylacetamide, manufactured by Showa Denko K.K.
* 6: N-Vinylpyrrolidone, Nippon Shokubai Co., Ltd.
* 7: N-vinyl-ε-caprolactam, manufactured by Tokyo Chemical Industry Co., Ltd.
* 8: N-vinylphthalimide, manufactured by Tokyo Chemical Industry Co., Ltd.
* 9: “PMA-ST”, manufactured by Nissan Chemical Industries, Ltd.
* 10: “Denka Black” manufactured by Denki Kagaku Kogyo Co., Ltd.
* 11: “UV3000B”, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.
* 12: “UX3301” manufactured by Nippon Kayaku Co., Ltd.
* 13: Shin-Nakamura Chemical Co., Ltd.
* 14: “IRGACURE907”, manufactured by BASF Corporation

From the results in Table 1, it can be seen that the sample of the developing roller belonging to the range of the examples shows good results for the adhesion between the base layer and the surface layer without causing printing defects or roller defects. It was. On the other hand, the sample of the developing roller belonging to the range of the comparative example had a problem in any of the evaluation items.

According to the present invention, it is possible to provide a conductive roller that can suppress image defects and is excellent in adhesion of a coating film formed on the outer peripheral side of the base layer. In addition, according to the present invention, it is possible to provide an image forming apparatus in which the occurrence of image defects is greatly reduced.

DESCRIPTION OF SYMBOLS 1 Conductive roller 2 Shaft 3 Base layer 4 Surface layer 5 Intermediate layer 11 Photoconductor 12 Charging roller 13 Toner supply roller 14 Toner accommodating part 15 Toner 16 Developing roller 17 Cleaning blade 18 Transfer roller 19 Cleaning roller

Claims (7)

1. A conductive roller comprising a shaft, a base layer formed on the outer peripheral side of the shaft, and a coating film formed on the outer peripheral side of the base layer,
   The coating film comprises at least an ultraviolet curable resin and at least one selected from the group consisting of N-vinyl amide and N-vinyl imide in an amount of 1 to 20 parts by mass with respect to 100 parts by mass of the ultraviolet curable resin. A conductive roller comprising the conductive roller.
2. The conductive roller according to claim 1, wherein the coating film is a surface layer formed on the base layer or an intermediate layer formed between the base layer and the surface layer.
3. 3. The conductivity according to claim 1, wherein the N-vinylamide is at least one selected from the group consisting of N-vinylacetamide, N-vinylpyrrolidone, and N-vinyl-ε-caprolactam. roller.
4. 4. The conductive roller according to claim 1, wherein the N-vinylimide is N-vinylphthalimide.
5. The conductive roller according to any one of claims 1 to 4, wherein the coating film contains at least one selected from the group consisting of silica and carbon black.
6. The conductive roller according to claim 5, wherein the total content of the silica and the carbon black is 3 to 15 parts by mass with respect to 100 parts by mass of the ultraviolet curable resin.
7. An image forming apparatus comprising the conductive roller according to any one of claims 1 to 6.

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