JP2006337673A - Developing roller, developing device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve adhesive properties between a resin layer containing a ultraviolet curing resin that is excellent in productivity and an elastic layer, in particular, an elastic layer containing silicone rubber, and to provide a developing roller that has excellent durability and such a laminated structure. <P>SOLUTION: The developing roller has an elastic layer along the peripheral face of a shaft core body, and a resin layer on the outside of the elastic layer. The resin layer is formed from a cured product of a carboxyl-group-containing ultraviolet curing resin composition. The resin composition satisfies the following expression (I): 800≤A(%)×B(mg×KOH/g)≤8000, wherein A represents mass% of the carboxyl-group-containing ultraviolet curing resin component of the resin layer, and B represents the acid number of the carboxyl-group-containing ultraviolet curing resin component. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a developing roller, and more specifically, in an apparatus (hereinafter collectively referred to as an electrophotographic apparatus) that employs an electrophotographic system for image formation, such as a receiving apparatus such as a copying machine, a printer, or a facsimile. The present invention relates to a developing roller used in the above, a developing device using the developing roller, and an image forming apparatus.

  In an electrophotographic apparatus that uses an electrophotographic system for image formation, such as a copying machine, a facsimile machine, and a printer, developing rollers for various purposes are used in the image forming process. For example, in an electrophotographic apparatus of a one-component development system, a developing roller in which a developer is carried on the surface in a step of developing an electrostatic latent image formed on the surface of a photoreceptor with a developer, that is, in a developing step A method is used in which the developer is moved in contact with the surface of the photoreceptor. The elastic layer of the developing roller used in this step needs to be in pressure contact with the photosensitive member with a predetermined contact width, is easily deformed, and at the same time has excellent deformation recovery properties, and has an elastic layer (lower layer). What has high adhesiveness is desired. In addition, the developer supplied in the developing device can be easily deformed even when it is carried thinly using a blade that contacts the elastic layer on the surface of the developing roller. It is necessary that the resin layer on the surface is not easily peeled off or scraped off.

  A developing roller used in an electrophotographic apparatus is required to have deformation recovery (that is, setability) that is important in maintaining an appropriate contact state in addition to basic performance such as developer carrying characteristics. For example, it is known that a relatively preferable performance can be obtained by using a urethane resin in a resin layer coated as a surface layer located on the outermost side of the developing roller. However, when a conventional thermosetting resin is used as a flexible material that can easily obtain deformation recovery, facilities and processes (time) are required for curing and drying.

  On the other hand, in the case of an ultraviolet curable resin, uniform curing is possible in a short time, and studies have been repeated. Patent Document 1 discloses a foam roller having a cost merit such that a long drying line is not required by applying and curing an ultraviolet curable resin on the surface of an elastic layer that is a foam. Further, Patent Document 2 discloses an elastic roller that does not have a complicated surface curing treatment step by impregnating and curing a radiation-sensitive acrylic monomer on the surface of the elastic layer of epichlorohydrin rubber.

On the other hand, in a developing roller having a structure in which an elastic body layer and a surface resin layer are laminated in this order on the outer periphery of the shaft core body, it is durable that the elastic body layer and the surface resin layer are laminated with good adhesion. It is important to secure sex. As a method for improving the adhesion with the surface resin layer when the elastic body layer is formed using silicone rubber, Patent Document 3 discloses that a resin layer provided on the elastic body layer has an amide bond or a urethane bond. A method of heating and forming a resin raw material comprising at least a resin component having an amine-based silane coupling agent and improving the adhesiveness thereof is disclosed.
JP 2002-310136 A JP 2002-082514 A JP 2001-323160 A

  By using an ultraviolet curable resin for forming the resin layer provided on the elastic layer, a heating process and an apparatus therefor when using a resin material that requires heat treatment can be omitted, and the manufacturing cost can be reduced. However, depending on the type of the ultraviolet curable resin, the adhesion between the resin layer obtained by using the resin and the elastic body layer thereunder may not be sufficient. Therefore, the addition of a surfactant as disclosed in Patent Document 3 can be considered. However, when an ultraviolet curable resin is used, the heat treatment is omitted, so that the added surfactant oozes from the resin layer and develops. There is a possibility of contaminating parts in the apparatus and the image forming apparatus.

  The present invention solves the above-mentioned problems, and the object of the present invention is to provide adhesion between an elastic body layer, particularly an elastic body layer containing silicone rubber, and a resin layer containing an ultraviolet curable resin having excellent productivity. An object of the present invention is to provide a developing roller having such a laminated structure which is improved and has excellent durability. Another object of the present invention is to provide a developing device and an image forming apparatus that use the developing roller to provide a good image at the time of durability and that do not cause peeling.

  In order to solve the above-mentioned problems, the present inventors have intensively studied and studied. When UV curable resin is used, curing is performed in a short time and productivity is improved. However, depending on the type of UV curable resin, the adhesion of the resin layer to the surface of the elastic layer containing rubber material Was confirmed to be low. The present inventors have further researched, and in a developing roller having a laminated structure in which a surface layer is provided on the base layer, an appropriate amount of a carboxyl group-containing UV curable resin is provided as a material for the layer located on the outside (surface layer). By using the resin material contained, it has been found that it is possible to provide a developing roller having excellent adhesion to the surface of the layer (base layer) containing the rubber material located inside, and the present invention has been completed. It was.

That is, the developing roller of the present invention is a developing roller having an elastic layer on the outer peripheral surface of the shaft core and further having a resin layer outside the elastic layer,
The resin layer is made of a cured product of an ultraviolet curable resin composition containing a carboxyl group, and the resin composition has the following formula (I):
800 ≦ A (%) × B (mg · KOH / g) ≦ 8000 (I)
A:% by mass of the ultraviolet curable resin component containing a carboxyl group in the resin layer
B: A developing roller characterized by satisfying the acid value of an ultraviolet curable resin component containing a carboxyl group.

  A developing device according to the present invention includes a developing roller capable of carrying a developer in a state of being in contact with or pressed against a latent image carrier that carries a latent image, and the developing roller is attached to the latent image carrier. In a developing device for visualizing the latent image as a developer image by applying a developer, the developing roller is a developing roller having a configuration satisfying the relationship of the above formula (I). is there.

  The image forming apparatus of the present invention is an image forming apparatus having a latent image carrier capable of carrying a latent image and a developing device for visualizing the latent image with a developer. An image forming apparatus having a developing device including a developing roller having a configuration satisfying the above relationship.

  The developing roller according to the present invention uses an ultraviolet curable resin containing a carboxyl group for the resin layer provided on the elastic layer, thereby enabling curing in a very short time with simple equipment, and excellent productivity. In addition, the adhesion between the resin layer and the elastic body layer is improved, and the coating film has excellent durability.

  Further, since the developing device and the image forming apparatus of the present invention have the developing roller having the above-described configuration, the image at the time of durability is good, and the developing roller is not easily peeled off.

  The developing roller of the present invention is a developing roller comprising two layers on the outer peripheral surface of the shaft core body, and has an elastic body layer on the outer peripheral surface of the shaft core body and a resin layer on the outer side thereof, and the resin By including an ultraviolet curable resin containing a carboxyl group in the resin component in the layer, the adhesion of the resin layer is improved, the strength of the coating is improved, and the developing roller has excellent durability.

  By using a developing roller having the constitutional features of the present invention, it is possible to cure in a short time by ultraviolet curing and simplify equipment, and at the same time, it has excellent durability and excellent image quality due to sufficient adhesion. Can be held for a long time. The developing roller of the present invention is formed as having a function corresponding to the intended application after imparting conductivity using means conventionally used according to the situation used in the electrophotographic apparatus. can do.

  Hereinafter, the present invention will be described in more detail.

  1 and 2 schematically show an example of the structure relating to the developing roller of the present invention. The developing roller 1 of the present invention has a shaft core 11 made of a conductive material such as a metal as a shaft core at the center, and an elastic body on the outer peripheral surface of the shaft core 11 as a roller layer. A layer (base layer) 12 is fixed, and a structure in which a resin layer (surface layer) 13 is laminated on the outer peripheral surface of the elastic body layer 12 is configured. Here, a description will be given of a developing roller having two layers on the outer peripheral surface of the shaft core as described above.

  The shaft core itself has a columnar or hollow cylindrical shape and often uses a shaft core 11 formed of a conductive material such as metal. However, the developing roller is electrically insulated. When used in a state in which the shaft core is used, it may be made of a non-conductive material as long as the shape of the shaft core itself can be firmly held against an external force applied to the developing roller. Even if such a developing roller is used with an electrical bias applied or grounded, the main body is made of a non-conductive material instead of being composed of a conductive material. It is also possible to use a material which is formed of a material and has a structure in which the surface is subjected to a conductive treatment satisfying desired conductivity, for example, a coating with a highly conductive coating layer.

  Since a developing roller used in an electrophotographic apparatus is generally used with an electric bias applied or grounded, the shaft core body is a conductive base, so-called shaft core metal. 11 forms. In the developing roller, the shaft core 11 is not only a support member, but also functions as an electrode of the charging member. For example, a metal or alloy such as aluminum, copper alloy, stainless steel, or chromium At least the outer peripheral surface of iron plated with nickel or the like, synthetic resin, or the like is made of a conductive material sufficient to apply a predetermined voltage to the roller layer formed thereon. In the developing roller used in the electrophotographic apparatus, the outer diameter of the conductive substrate that is the shaft core is usually in the range of 4 to 10 mm.

  The elastic body layer 12 serving as a base layer has flexibility and is formed as a molded body using rubber as a raw material main component. The hardness of the elastic body 12 may be selected so that an appropriate nip width can be obtained in accordance with the configuration, but it is preferably selected in the range of 10 to 70 ° in terms of Asker-C hardness. If the hardness (Asker-C) is less than 15 °, rubber elasticity is difficult to obtain, whereas if it exceeds 70 °, it is difficult to obtain an appropriate nip width. More preferably, the hardness (Asker-C) of the rubber molded body forming the elastic layer is more preferably selected in the range of 15 to 55 °. As the rubber as the main ingredient of the elastic layer 12, various rubbers conventionally used for developing rollers can be used. Specifically, ethylene-propylene-diene copolymer rubber (EPDM), acrylonitrile-butadiene rubber (NBR), chloroprene rubber (CR), natural rubber (NR), isoprene rubber (IR), styrene-butadiene rubber (SBR). ), Fluoro rubber, silicone rubber, epichlorohydrin rubber, hydride of NBR, polysulfide rubber, urethane rubber and the like. To the material selected from these, other desired components for forming the elastic layer are added as necessary, and used as a material for forming the elastic layer. When the rubber layer is molded by adding other components to the elastic layer, these rubber materials can be used singly or in combination of two or more as long as the desired elastic body hardness is given. The mixing amount can also be selected according to the characteristics required for the intended application. Among these, the use of a rubber material mainly composed of silicone rubber can provide an appropriate nip width and better adhesion to an ultraviolet curable resin containing a carboxyl group used in the resin layer. Particularly preferred. In this case, the blending ratio of the silicone rubber is preferably at least 40% by mass with respect to the entire rubber material.

  Furthermore, in the developing roller of the present invention, when a rubber molded body for forming the elastic layer is formed, components necessary for the functions required for the elastic layer itself according to the specific use of the developing roller, for example, Conductive agents, non-conductive fillers, etc., and various additive components used when forming rubber moldings, for example, various additives such as cross-linking agents, catalysts, dispersion accelerators, etc. are used as the main rubber material. It can mix | blend suitably.

  As a conductive agent added for the purpose of imparting conductivity to the elastic body layer, various conductive metals or alloys such as carbon black, graphite, aluminum, copper, tin, stainless steel, tin oxide, zinc oxide, indium oxide, Various conductive metal oxides such as titanium oxide, tin oxide-antimony oxide solid solution, tin oxide-indium oxide solid solution, and fine powders such as insulating substances coated with these conductive materials can be used. Among these, carbon black can be suitably used because it can be obtained relatively easily and good chargeability can be obtained regardless of the type of the main rubber material. As a means for dispersing the finely powdered conductive agent in the main rubber material, conventionally used means such as a roll kneader, a Banbury mixer, a ball mill, a sand grinder, a paint shaker, etc. are used as the main rubber material. It may be used appropriately according to the situation.

In addition, as a means for imparting conductivity to the elastic layer, a method of adding a conductive polymer compound instead of the conductive agent or together with the conductive agent can be used. For example, as a conductive polymer compound, as a host polymer, polyacetylene, poly (p-phenylene), polypyrrole, polythiophenine, poly (p-phenylene oxide), poly (p-phenylene sulfide), poly (p-ferene vinylene) ), Poly (2,6-dimethylphenylene oxide), poly (bisphenol A carbonate), polyvinylcarbazole, polydiacetylene, poly (N-methyl-4-vinylpyridine), polyaniline, polyquinoline, poly (phenylene ether sulfone), etc. These are used as dopants, such as AsF ₅ , I ₂ , Br ₂ , SO ₃ , Na, K, ClO ₄ , FeCl ₃ , F, Cl, Br, I, Kr, and other ions, Li, TCNQ (7 , 7,8,8-tetracyanoquinodimethane) has been used in the past. The

  Examples of the non-conductive filler that can be added to the rubber molded body include diatomaceous earth, quartz powder, dry silica, wet silica, titanium oxide, zinc oxide, aluminosilicate, calcium carbonate, and the like.

  Examples of the crosslinking agent used in producing the rubber molded body include di-t-butyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, dicumyl peroxide, t -Butyl peroxybenzoate, p-chlorobenzoyl peroxide, etc. can be mentioned. For example, when liquid silicone rubber is used, the rubber components can be cross-linked using a platinum catalyst with polyorganohydrogensiloxane as a cross-linking component.

  The thickness of the elastic layer is preferably 0.5 mm or more, more preferably 1.0 mm or more in order to ensure a uniform nip width when contacting the latent image carrier and satisfy suitable setting properties. Is desirable. Although there is no upper limit on the thickness of the elastic layer as long as the outer diameter accuracy of the developing roller to be manufactured is not impaired, generally, if the thickness of the elastic layer is excessively increased, the production cost of the rubber molded body is reduced. In view of these practical restrictions, the thickness of the elastic body layer is preferably 6.0 mm or less, more preferably 5.0 mm or less. Therefore, the thickness of the elastic layer is desirably selected in the range of 0.5 to 6.0 mm, and more desirably selected in the range of 1.0 to 5.0 mm. The thickness of the elastic body layer is appropriately selected according to the hardness.

  As shown in FIGS. 1 and 2, on the outer side of the elastic body layer 12, there is a resin layer 13 that is laminated to cover the outer peripheral surface of the elastic body layer 12 as a surface layer. This resin layer is made of a cured product of an ultraviolet curable resin composition containing a carboxyl group.

In the developing roller of the present invention, the carboxyl group-containing ultraviolet curable resin component contained in the ultraviolet curable resin composition for forming the resin layer 13 satisfies the following formula (I):
800 ≤ A (%) x B (mg · KOH / g) ≤ 8000 (I)
A:% by mass of the ultraviolet curable resin component containing a carboxyl group in the resin layer
B: Acid value of ultraviolet curable resin component containing carboxyl group When the value of A × B in the above formula is less than 800, it is not sufficient to obtain the effect of addition, and sufficient adhesion improvement on the surface of the surface layer is obtained. Absent. On the other hand, if the equivalent value exceeds 8000, the flexibility of the base resin is likely to be impaired, and problems such as cracking and a decrease in developer transportability may occur. The preferable range of the A × B value is appropriately adjusted according to the type of the carboxyl group-containing ultraviolet curable resin component serving as a base, but is more preferably in the range of 2000 to 6000, and further in the range of 2000 to 4000. preferable. Here, the “acid value” is a value measured by a method according to JIS K-0070.

  In the present invention, the mass% of the carboxyl group-containing ultraviolet curable resin component contained in the resin layer may be obtained by calculation from the blending ratio when the roller is actually produced. Moreover, in the surface layer already coated, A * B value can be calculated | required by measuring an "acid value" with respect to a resin layer component.

  An example of A × B calculation is shown below.

UV curable resin containing a carboxyl group (acid value: 100) 30 parts by mass Other UV curable resin (not containing a carboxyl group) 70 parts by mass Other resin components (reactive diluent, polymerization initiator) 10 parts by mass Part Conductivity imparting component (carbon black) 15 parts by mass Here, A:% by mass of the ultraviolet curable resin component containing a carboxyl group in the resin layer is:
30 / (30 + 70 + 10 + 15) = 0.24 = 24.0 (%)
Next, since the acid value of B: an ultraviolet curable resin component containing a carboxyl group is 100 (mg · KOH / g), the A × B value is
24.0 (%) × 100 (mg · KOH / g) = 2400.

  The ultraviolet curable resin composition for forming the resin layer contains at least an ultraviolet curable resin component containing a carboxyl group and an ultraviolet polymerization initiator. The ultraviolet curable resin component containing a carboxyl group is a resin component (for example, oligomer or polymer) for ultraviolet curing that has a carboxyl group in the molecule and can be polymerized by the action of an ultraviolet polymerization initiator. The resin component having a carboxyl group in the molecule can be used alone or blended with other ultraviolet curing resin components having no carboxyl group in the molecule depending on the desired properties of the resin layer.

  The mass% (A) of the ultraviolet curable resin containing a carboxyl group in the resin layer is preferably 3% to 55% from the viewpoint of adhesiveness, although it depends on the type. Further, it is more preferably 4% to 40% from the viewpoint of imparting flexibility to the resin.

  The ratio of the resin component (x) containing a carboxyl group and the other resin component (y) containing no carboxyl group can also be selected within a range where desired characteristics can be obtained. For example, x: y (mass The ratio can be selected from the range of 100: 0 to 40:60.

  As a resin component for ultraviolet curing, a (meth) acrylate oligomer can be suitably used. Such (meth) acrylate oligomers include, for example, epoxy (meth) acrylate oligomers, urethane (meth) acrylate oligomers, ether (meth) acrylate oligomers, ester (meth) acrylate oligomers, polycarbonate (meth) acrylate oligomers, and the like. Is mentioned.

  (Meth) acrylate oligomer includes polyethylene glycol, polyoxypropylene glycol, polytetramethylene ether glycol, bisphenol A type epoxy resin, phenol novolac type epoxy resin, polyhydric alcohol and ε-caprolactone adduct, It can be synthesized by reaction with acrylic acid or by urethanizing a polyisocyanate compound and a (meth) acrylate compound having a hydroxyl group.

  Moreover, a urethane type (meth) acrylate oligomer is obtained by urethanizing a polyol, an isocyanate compound, and the (meth) acrylate compound which has a hydroxyl group. As the polyol and isocyanate compound, those prepared by a method in which a polyurethane prepolymer is subjected to a cross-linking reaction, or a conductive material as an additive is blended in advance with a polyol, and the polyol prepared in this blend is polymerized by a one-shot method. Examples thereof include those prepared by a method of reacting with an isocyanate to obtain a polyurethane resin.

  When producing a polyurethane resin by this one-shot method, as a polyhydroxyl compound to be used, a polyol used for producing a general flexible polyurethane foam or urethane elastomer, for example, a polyether polyol having a polyhydroxyl group at the terminal, Polyester polyol and polyether polyester polyol which is a copolymer of both are mentioned. In addition, general polyols such as polyolefin polyols such as polybutadiene polyol and polyisoprene polyol, and so-called polymer polyols obtained by polymerizing ethylenically unsaturated monomers in polyols can also be used.

  On the other hand, as the isocyanate compound to be reacted with the polyhydroxyl compound, polyisocyanate used for producing general flexible polyurethane foam and urethane elastomer, that is, tolylene diisocyanate (TDI), crude TDI, 4,4′-diphenylmethane. Diisocyanate (MDI), crude MDI, aliphatic polyisocyanates having 2 to 18 carbon atoms, alicyclic polyisocyanates having 4 to 15 carbon atoms, mixtures of these polyisocyanates and modified products thereof such as partially reacting with polyols A prepolymer or the like obtained by making it to be used.

  Further, other components such as a blending component are not particularly limited. However, in view of the function of supporting toner particles as a developer, urethane acrylate is used from the viewpoint of self-film reinforcing property, toner charging property, and the like. Is preferably used.

  For example, when an acrylate containing a carboxyl group is blended based on urethane acrylate having excellent flexibility as a blend of ultraviolet curable resins, it is easy to obtain a developing roller having excellent elasticity and good adhesion.

  The ultraviolet curable resin composition is blended with a reactive diluent having a polymerizable double bond for viscosity adjustment as necessary. Examples of such a reactive diluent include a monofunctional, bifunctional or polyfunctional polymerizable compound having a structure in which (meth) acrylic acid is bonded to a compound containing an amino group or a hydroxyl group by an esterification reaction or an amidation reaction. Can be used. These diluents are usually preferably used in an amount of 10 to 200 parts by mass per 100 parts by mass of the (meth) acrylate oligomer (A).

  For example, the reactive diluent may be a monofunctional or bifunctional or higher polyfunctional acrylate monomer. Examples of monofunctional acrylate monomers include 2-ethylhexyl carbitol acrylate, 2-hydroxy-3-phenoxypropyl acrylate, dicyclopentenyl acrylate, N-vinyl-2-pyrrolidone, isobornyl acrylate, isobornyl methacrylate, Decyl acrylate, isodecyl methacrylate, stearyl acrylate, isooctyl acrylate, n-lauryl acrylate and the like can be used alone or in admixture of two or more.

  Examples of the polyfunctional acrylate monomer include neopentyl glycol diacrylate, diacrylate of a 2-mol adduct of propylene oxide of neopentyl glycol, diethylene glycol diacrylate, diacrylate of an ester of hydroxypivalic acid and neopentyl glycol, 1,6- Hexanediol diacrylate, 1,4-butanediol diacrylate, tripropylene glycol diacrylate, bisphenol A dimethacrylate, ethylene oxide modified bisphenol A diacrylate, 1,3-butylene glycol dimethacrylate, dicyclopentanyl diacrylate, di Pentaerythritol hexaacrylate, dipentaerythritol monohydroxypentaacrylate, ditrimethylolpro Down tetraacrylate, glycerol acrylate, methoxylated cyclohexyl diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, pentaerythritol tetramethacrylate, etc. may be used alone or in admixture of two or more.

  As the ultraviolet polymerization initiator, known ones can be used, for example, 4-dimethylaminobenzoic acid, 4-dimethylaminobenzoic acid ester, 2,2-dimethoxy-2-phenylacetophenone, acetophenone diethyl ketal, alkoxy Benzophenone derivatives such as acetophenone, benzyldimethyl ketal, benzophenone and 3,3-dimethyl-4-methoxybenzophenone, 4,4-dimethoxybenzophenone, 4,4-diaminobenzophenone, alkyl benzoylbenzoate, bis (4-dialkylaminophenyl) Benzyl derivatives such as ketone, benzyl and benzylmethyl ketal, benzoin derivatives such as benzoin and benzoin isobutyl ether, benzoin isopropyl ether, 2-hydroxy-2-methylpropion Non, 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. These may be used individually by 1 type and may use 2 or more types together. The blending amount of the ultraviolet polymerization initiator is preferably 0.1 to 10 parts by mass per 100 parts by mass of the (meth) acrylate oligomer.

  In the present invention, in addition to the essential components, a tertiary amine such as triethylamine or triethanolamine, or an alkylphosphine such as triphenylphosphine is used to promote the photopolymerization reaction by the photopolymerization initiator, if necessary. A photopolymerization accelerator, a thioether photopolymerization accelerator such as p-thiodiglycol, and the like may be added. The amount of these compounds added is usually preferably in the range of 0.01 to 10 parts by mass per 100 parts by mass of the (meth) acrylate oligomer.

  Furthermore, in the developing roller of the present invention, when forming a resin film body that forms the resin layer, components necessary for the functions required for the resin layer itself, for example, a conductive agent, in accordance with the individual use of the developing roller , Non-conductive fillers, and various additive components used when forming resin film bodies, for example, various additives such as cross-linking agents, catalysts, dispersion accelerators, etc. can do. Note that additives such as a conductive agent and a non-conductive filler can be appropriately selected from those exemplified above as additives that can be contained in the elastic layer according to the main resin material. Moreover, the addition amount can be suitably selected according to the addition purpose, as long as the characteristics of the resin layer to be formed are maintained within the range in which the effects of the present invention are exhibited.

  The thickness of the resin layer 13 (surface layer) is preferably selected to be 3 μm or more in order to ensure sufficient wear resistance. On the other hand, the developing roller has conductivity, and in this case, in order to achieve uniform conductivity, the thickness of the resin layer is preferably limited to 100 μm or less. In addition, when the thickness of the resin layer is less than 3 μm, it is difficult to uniformly apply and form the desired thin film thickness on the surface of the elastic layer, while the hardness of the resin layer is the hardness of the elastic layer. Since it is higher than the hardness, if the film thickness exceeds 100 μm, the influence on the deformability of the entire developing roller becomes large, which is not preferable. Moreover, from the point which can suppress the hardness of a resin layer low, 3 micrometers or more and 50 micrometers or less are more preferable, and more preferably 8 micrometers or more and 30 micrometers or less from a compatible surface with productivity. Moreover, what is necessary is just to select the thickness of a resin layer suitably according to the hardness etc. in said range. The thickness of the resin layer of the present invention is measured and determined by observing the cross section with an optical microscope or the like using a sample cut out from a roller.

  The hardness of the surface of the developing roller after the resin layer is formed is not particularly limited, but the hardness of the surface of the developing roller is in the range of JIS-A hardness 10 ° to 40 ° from the viewpoint that an appropriate nip width can be easily obtained. Is preferred.

  For the formation of the resin layer 13 (surface layer), a method can be used in which the resin raw material, which is the raw material of the resin film body, is applied in a liquid state to the surface of the elastic body layer, and then the resin film body is formed. The method for applying the resin material is not particularly limited, but the resin material is uniformly applied to the surface of the elastic layer with a desired thickness by a method such as air spray, roll coating, curtain coating, or dipping.

After application, an ultraviolet irradiation treatment is performed to obtain a resin film body. As a light source for irradiating ultraviolet rays, any of the normally used mercury lamps, high-pressure mercury lamps, ultra-high pressure mercury lamps, metal halide lamps, xenon lamps, etc. can be used. Good. The conditions of ultraviolet irradiation may be appropriately selected according to the type and application amount of the ultraviolet curable resin, but an illuminance of 500 to 1200 mW / cm ² and an integrated light amount of 200 to 4800 mJ / cm ² are appropriate.

  As described above, the developing roller of the present invention is a developing roller having two layers on the outer peripheral surface of the shaft core body, and has an elastic body layer on the outer peripheral surface of the shaft core body, With the use of a carboxyl group-containing UV curable resin, while taking advantage of productivity improvements such as uniform curability of the UV curable resin in a short time and simplified equipment, The adhesion of the coating layer is improved, the strength of the coating is improved, and the durability is excellent.

  Because of this advantage, the developing roller of the present invention can be suitably used as a developing roller in an electrophotographic apparatus or the like. When used for a developing roller, the UV curable resin has good curability and productivity, such as simpler equipment, as well as high adhesiveness of the coating and excellent durability. Image quality can be maintained after long-term use. Further, the above-described advantages become more remarkable under the condition that the electrophotographic apparatus to be used is speeded up and the process speed, that is, the speed of the surface of the photoreceptor is increased.

  FIG. 3 is a cross-sectional view showing a schematic configuration of a developing device using the developing roller of the present invention as a developing roller and an image forming device using the developing roller as a developing roller.

  The photosensitive drum 21 serving as a latent image carrier rotates in the direction of arrow A, and is uniformly charged by a charging device 22 for charging the photosensitive drum 21, and is an exposure unit that writes an electrostatic latent image on the photosensitive drum 21. An electrostatic latent image is formed on the surface of the laser beam 23. The electrostatic latent image is provided close to the photosensitive drum 21 and is supplied with toner as a developer by a developing device 2 held in a process cartridge (not shown) that is detachable from the image forming apparatus main body. Is developed and visualized as a toner image.

  Development is so-called reversal development in which a toner image is formed on the exposed portion. The visualized toner image on the photosensitive drum 21 is transferred to a paper 33 as a recording medium by a transfer roller 29. The paper 33 to which the toner image has been transferred is subjected to a fixing process by the fixing device 32, discharged outside the device, and the printing operation is completed.

  On the other hand, the untransferred toner remaining on the photosensitive drum 21 without being transferred is scraped off by the cleaning blade 30 and stored in the waste toner container 31, and the cleaned photosensitive drum 21 repeats the above operation.

  The developing device 2 includes a developing device 34 that contains a non-magnetic toner 28 as a one-component developer, and a developer carrying member that is positioned in an opening extending in the longitudinal direction in the developing container 34 and is opposed to the photosensitive drum 21. A developing roller 25 for developing the electrostatic latent image on the photosensitive drum 21 to visualize it.

  The developing roller 25 is in contact with the photosensitive drum 21 with a contact width. In the developing device 2, the developing roller 26 is in contact with the contact portion of the elastic blade 27 with the surface of the developing roller 25 in the developing container 34 on the upstream side in the rotational direction of the developing roller 25 and is rotatably supported. Has been.

  Hereinafter, the present invention will be described more specifically with reference to examples. These examples are examples of the best mode of the present invention, but the present invention is not limited to the examples. The developing roller produced by the method shown in the embodiment can be suitably used as a developing roller used in an electrophotographic apparatus. In the specific examples described below, commercially available high-purity products were used as reagents used in the respective examples unless otherwise specified.

[Example 1] Developing roller 1
An SUS metal core (φ8 mm) with nickel plating applied as a shaft core was further applied with an adhesive and baked. This shaft core is placed in a mold, and as a raw material rubber, a liquid silicone rubber (a linear polydimethylsiloxane blocked with a terminal vinyl group, a branched polysiloxane segment having one vinyl group, and a bifunctional dimethyl group) Addition of a polysiloxane mixture consisting of a block polymer consisting of a linear oil segment containing siloxane and an organosiloxane having two or more silicon-bonded hydrogen atoms in one molecule as a cross-linking agent and a platinum-based catalyst Type silicone rubber composition), silica powder as a heat resistance imparting agent which is an inorganic fine powder, and carbon black as a conductivity imparting agent are mixed to prepare a liquid rubber compound, which is then formed into a cavity formed in the mold. Injected. Subsequently, the mold was heated at 150 ° C. for 20 minutes to cure and cure the silicone rubber, and after cooling, the mold was removed to produce a roller having an elastic body layer having a thickness of 4 mm on the outer periphery of the shaft core body. .

  Unidic V-4221 (Dainippon Ink Chemical Co., Ltd., ester urethane acrylate) 94 parts by mass, Unidic V-3021 (Dainippon Ink Chemical Co., Ltd., epoxy acrylate, acid value (B) = 208) 6 Parts by mass, 10 parts by mass of N-vinyl-2-pyrrolidone, Irgacure # 184 (manufactured by Ciba Specialty Chemicals, hydroxycyclohexyl phenyl ketone, photopolymerization initiator), 4 parts by mass, # 990 (manufactured by Mitsubishi Chemical Corporation, Carbon black) A UV curable resin composition consisting of 17 parts by mass was thoroughly mixed and applied with a roll coater. Then, using a high-pressure mercury lamp (Harrison Toshiba Lighting Co., Ltd.), rotating the roller and irradiating ultraviolet rays under the conditions of a distance of 10 cm, an illuminance of 800 mW, and an irradiation time of 5 seconds, the surface layer of about 30 μm is elastic. The developing roller 1 provided on the outer periphery of the layer was produced. The mass% (A) of the ultraviolet curable resin component containing a carboxyl group in the resin component of the surface layer of the developing roller 1 thus produced was 4.6, and the A × B value was 956.

[Example 2] Developing roller 2
The ultraviolet curable resin composition for forming the surface layer was prepared by adding 75 parts by mass of Unidic V-4221 (Dainippon Ink Chemical Co., Ltd., ester urethane acrylate) and Unidic V-3021 (Dainippon Ink Chemical Co., Ltd.). , Epoxy acrylate, acid value (B) = 208) 25 parts by mass, 10 parts by mass of N-vinyl-2-pyrrolidone, Irgacure # 184 (manufactured by Ciba Specialty Chemicals Co., Ltd., hydroxycyclohexyl phenyl ketone, photopolymerization initiator) A developing roller 2 was produced in the same manner as in Example 1 except that the content was changed to 4 parts by mass and 17 parts by mass of # 990 (manufactured by Mitsubishi Chemical Corporation, carbon black). The mass% (A) of the ultraviolet curable resin component containing a carboxyl group in the resin component of the surface layer of the developing roller 2 thus produced was 19.1 and the A × B value was 3969.

[Example 3] Developing roller 3
The UV curable resin composition forming the surface layer was mixed with 50 parts by mass of Unidic V-4221 (manufactured by Dainippon Ink Chemical Co., Ltd., ester urethane acrylate) and Unidic V-3021 (manufactured by Dainippon Ink Chemical Co., Ltd.). Epoxy acrylate, acid value (B) = 208) 50 parts by mass, N-vinyl-2-pyrrolidone 10 parts by mass, Irgacure # 184 (manufactured by Ciba Specialty Chemicals, hydroxycyclohexyl phenyl ketone, photopolymerization initiator) A developing roller 3 was produced in the same manner as in Example 1 except that the content was changed to 5 parts by mass and 17 parts by mass of # 990 (manufactured by Mitsubishi Chemical Corporation, carbon black). The mass% (A) of the ultraviolet curable resin component containing a carboxyl group in the resin component of the surface layer of the developing roller 3 thus produced was 38.0, and the A × B value was 7909.

[Embodiment 4] Developing roller 4
The ultraviolet curable resin composition for forming the surface layer is composed of 80 parts by mass of Unidic V-4350 (Dainippon Ink Chemical Co., Ltd., ether urethane acrylate) and Unidic V-3021 (Dainippon Ink Chemical Co., Ltd.). , Epoxy acrylate, acid value (B) = 208) 20 parts by mass, 10 parts by mass of N-vinyl-2-pyrrolidone, Irgacure # 184 (manufactured by Ciba Specialty Chemicals, hydroxycyclohexyl phenyl ketone, photopolymerization initiator) The developing roller 4 was produced in the same manner as in Example 1 except that the amount was changed to 4 parts by mass and 17 parts by mass of # 990 (manufactured by Mitsubishi Chemical Corporation, carbon black). The mass% (A) of the ultraviolet curable resin component containing a carboxyl group in the resin component of the surface layer of the developing roller 4 thus produced was 15.31, and the A × B value was 3176.

[Embodiment 5] Developing roller 5
The ultraviolet curable resin composition for forming the surface layer is composed of 85 parts by mass of Unidic V-4263 (Dainippon Ink Chemical Co., Ltd., urethane acrylate), Unidic V-3021 (Dainippon Ink Chemical Co., Ltd., Epoxy acrylate, acid value (B) = 208) 15 parts by mass, N-vinyl-2-pyrrolidone 10 parts by mass, Irgacure # 184 (manufactured by Ciba Specialty Chemicals, hydroxycyclohexyl phenyl ketone, photopolymerization initiator) 4 The developing roller 5 was produced in the same manner as in Example 1 except that the weight was changed to 17 parts by mass, # 990 (manufactured by Mitsubishi Chemical Corporation, carbon black). The mass% (A) of the ultraviolet curable resin component containing a carboxyl group in the resin component of the surface layer of the developing roller 5 thus produced was 11.5, and the A × B value was 2382.

[Comparative Example 1] Developing roller 6
An ultraviolet curable resin composition for forming the surface layer was prepared by adding 100 parts by mass of Unidic V-4221 (Ester Urethane Acrylate, manufactured by Dainippon Ink & Chemicals, Inc.), 10 parts by mass of N-vinyl-2-pyrrolidone, Irgacure # 184. (Ciba Specialty Chemicals Co., Ltd., hydroxycyclohexyl phenyl ketone, photopolymerization initiator) 4 parts by mass, # 990 (Mitsubishi Chemical Co., Ltd., carbon black) 17 parts by mass Thus, the developing roller 6 was produced. The resin component on the surface layer of the developing roller 6 thus produced contained no carboxyl group, and the A × B value was 10 or less when measured.

[Comparative Example 2] Developing roller 7
The ultraviolet curable resin composition forming the surface layer was obtained by adding 97 parts by weight of Unidic V-4221 (Dainippon Ink Chemical Co., Ltd., ester urethane acrylate) and Unidic V-3021 (Dainippon Ink Chemical Co., Ltd.). Epoxy acrylate, acid value (B) = 208) 3 parts by mass, N-vinyl-2-pyrrolidone 10 parts by mass, Irgacure # 184 (manufactured by Ciba Specialty Chemicals Co., Ltd., hydroxycyclohexyl phenyl ketone, photopolymerization initiator) The developing roller 7 was produced in the same manner as in Example 1 except that the content was changed to 4 parts by mass and 17 parts by mass of # 990 (manufactured by Mitsubishi Chemical Corporation, carbon black). The mass% (A) of the ultraviolet curable resin component containing a carboxyl group in the resin component of the surface layer of the developing roller 7 thus produced was 2.3, and the A × B value was 476.

[Comparative Example 3] Developing roller 8
An ultraviolet curable resin composition for forming a surface layer was obtained by adding 25 parts by mass of Unidic V-4221 (Dainippon Ink Chemical Co., Ltd., ester urethane acrylate) and Unidic V-3021 (Dainippon Ink Chemical Co., Ltd.). Epoxy acrylate, acid value (B) = 208) 75 parts by mass, N-vinyl-2-pyrrolidone 10 parts by mass, Irgacure # 184 (manufactured by Ciba Specialty Chemicals Co., Ltd., hydroxycyclohexyl phenyl ketone, photopolymerization initiator) A developing roller 8 was produced in the same manner as in Example 1 except that the content was changed to 5 parts by mass and 17 parts by mass of # 990 (carbon black, manufactured by Mitsubishi Chemical Corporation). The mass% (A) of the ultraviolet curable resin component containing a carboxyl group in the resin component of the surface layer of the developing roller 8 thus produced was 57.0, and the A × B value was 11863.

[Comparative Example 4] Developing roller 9
An ultraviolet curable resin composition for forming a surface layer was prepared by adding 100 parts by mass of Unidic 17-849 (Dainippon Ink & Chemicals, Epoxy acrylate, acid value (B) = 11), N-vinyl-2-pyrrolidone. 20 parts by mass, Irgacure # 184 (Ciba Specialty Chemicals Co., Ltd., hydroxycyclohexyl phenyl ketone, photopolymerization initiator) 2 parts by mass, # 990 (Mitsubishi Chemical Corporation, carbon black) 18 parts by mass A developing roller 9 was prepared in the same manner as in Example 1. The mass% (A) of the ultraviolet curable resin component containing a carboxyl group in the resin component of the surface layer of the developing roller 9 thus produced was 71.4, and the A × B value was 786.

[Characteristic evaluation]
The developing roller obtained as described above was used as a developing roller and incorporated in Color Laser Printer LBP5500 (manufactured by Canon Inc.), and the following evaluations were made and various evaluations were performed. The surface resin layer was sufficiently cured in all cases.

  Evaluation of adhesion is made by putting a cut on the grid surface of about 5 mm square on the surface of the developing roller with a cutter knife, and attaching a cellophane adhesive tape for packaging (Nichiban Co., Ltd., cellophane adhesive tape for packaging). By peeling off, the situation was visually observed and judged. ○ when no peeling was confirmed on the adhesive surface, △ when a part of the resin layer was peeled off and adhered to the packaging cellophane adhesive tape (less than 90% of the tape area), and the cellophane adhesive tape for packaging The case where the resin layer was completely peeled off and adhered (90% or more in the area of the tape) was evaluated as x.

  The evaluation of the image level and durability was judged by observing the presence and change of image problems at the initial stage and before and after printing 6000 sheets, and the state of the roller surface after printing 6000 sheets. Initially, the evaluation of the images before and after printing 6000 sheets was: ◎ for good, ◯ for no problem, △ for slightly shaded, and for those with noticeable image defects such as dropout × It was. The durability was evaluated by comparing the images at the initial stage and before and after printing of 6000 sheets. No change over time, ◎ for those that are good or no problem, ◯ for those that are slightly degraded but no problem, Although there was no change, the case where there was a problem in the image itself was indicated by Δ, and the case where the problem occurred in the image over time was indicated by ×.

  The results of evaluation based on the above criteria are shown in Table 1.

  As described above, the overall evaluation is ◎ if there is no problem in adhesion and durability and the image level is good, ○ if there is no problem in any of the adhesion, durability, and image level, ○, adhesion, durability Those in which any of the problems occurred were marked with x. In Examples 1-5, there was no problem in performance of both adhesiveness and durability. Among them, Examples 2, 4, and 5 gave particularly good results. In Comparative Examples 1, 2 and 4 having an A × B value of less than 800, the adhesion between the elastic layer and the resin layer is insufficient, and in Comparative Example 3 having an A × B value of more than 8000, 6000 A satisfactory image could not be obtained when exceeding the number of sheets.

FIG. 3 is a diagram schematically illustrating an example of the overall configuration of the developing roller of the present invention. FIG. 2 is a cross-sectional view in a direction perpendicular to the axis of the developing roller shown in FIG. 1. It is explanatory drawing of the image forming apparatus using the developing device of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Developing roller 2 ... Developing apparatus 3 ... Image forming apparatus 11 ... Shaft core body 12 ... Elastic body layer (base layer)
13 ... Resin layer (surface layer)
21 ... photosensitive drum 22 ... charging device 23 ... laser beam 25 ... developing roller 26 ... developing roller 27 ... elastic blade 28 ... toner 29 ... transfer roller 30 ... cleaning blade 31 ... waste toner container 32 ... fixing device 33 ... paper 34 ... developing container

Claims (5)

A developing roller having an elastic layer on the outer peripheral surface of the shaft core, and further having a resin layer outside the elastic layer;
The resin layer is made of a cured product of an ultraviolet curable resin composition containing a carboxyl group, and the resin composition has the following formula (I):
800 ≦ A (%) × B (mg · KOH / g) ≦ 8000 (I)
A:% by mass of the ultraviolet curable resin component containing a carboxyl group in the resin layer
B: A developing roller characterized by satisfying the acid value of an ultraviolet curable resin component containing a carboxyl group.   The developing roller according to claim 1, wherein the elastic body layer is mainly made of silicone rubber.   The developing roller according to claim 1, wherein the thickness of the resin layer is selected in a range of 3 to 100 μm.   A developing roller capable of carrying a developer in a state of being in contact with or in pressure contact with the latent image carrying body carrying the latent image, and the developing roller applies the developer to the latent image carrying body to thereby form the latent image; A developing device for visualizing an image as a developer image, wherein the developing roller is the developing roller according to claim 1. In an image forming apparatus comprising a latent image carrier capable of carrying a latent image and a developing device for visualizing the latent image with a developer,
An image forming apparatus, wherein the developing device is the developing device according to claim 4.

Images