JP2009186585A - Method for manufacturing roller, developing roller and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing an accurate roller having no protrusion resulting from residue of silicone rubber on a roller surface, and further achieving prevention of corrosion on the roller surface caused by a thermally modified matter of a mold releasing agent. <P>SOLUTION: In the method for manufacturing the roller molded by arranging a core bar in a cylindrical metallic mold after applying the mold releasing agent to the inner surface of the cylindrical metallic mold, injection-molding liquid silicone rubber to the core bar concentrically and hardening it, the residue of silicone rubber and the mold releasing agent are removed by bringing the surface of the roller, which is removed from the metallic mold after primary hardening treatment, into contact with an adhesive tape before secondary hardening treatment. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method of manufacturing a roller that can be used for development, charging, transfer, cleaning, static elimination, etc. in an image forming apparatus employing an electrophotographic system such as a printer, a facsimile machine, and a copying machine, and a roller manufactured by the manufacturing method. The present invention relates to a developing roller and an image forming apparatus using the roller.

  Various image forming apparatuses adopting an electrophotographic system such as a laser printer, a copying machine, and a facsimile incorporate rollers such as a developing roller, a charging roller, and a transfer roller.

  In a roller used for such a purpose, a conductive elastic layer is usually formed around a cored bar. The formation of the elastic layer can be divided into two methods: a method of cutting out a desired shape by polishing and a method of forming a desired shape by injecting a material into a dedicated mold and curing. In particular, die molding is very often used because it does not require a post-process such as polishing and a highly accurate roller can be obtained. In this mold molding, a mold release agent is applied to a cylindrical cavity wall surface in which the inner diameter shape of the mold is processed with high precision, and then a core metal is disposed, and then a rubber such as liquid silicone rubber is placed in the cavity. It is possible to form a roller having an elastic layer around the cored bar by injecting the raw material, heat-curing (primary curing), and taking out from the mold (demolding). For the purpose of improving the demolding property, a release agent is applied to the cavity wall surface. The mold release agent reduces the frictional force at the contact surface between the mold cavity wall surface and the elastic layer. After the primary curing is completed, the silicone rubber after demolding has not been cured sufficiently. That is, an uncured reaction site may remain. Further, the silicone rubber after the primary curing often contains a low molecular weight silicone oil derived from a rubber raw material. Usually, immediately after demolding, secondary curing is performed at a temperature higher than the primary curing temperature, the curing is completed, and the low molecular weight silicone oil is evaporated to develop the original physical properties of silicone rubber.

  By the way, on the surface of the silicone rubber roller after the primary curing after molding (elastic layer surface), rubber burrs formed at the joints and sliding parts of the mold by casting into the mold adhere to the roller surface as silicone rubber residue. Often doing. Since the silicone rubber before the secondary curing is not sufficiently cured, a low molecular weight silicone oil is also present on the roller surface, so that the tackiness (adhesion) is large. For this reason, silicone rubber residue tends to adhere to the roller surface, and when the secondary curing is performed with the silicone rubber residue adhered to the roller surface, curing proceeds between the rubber residue and the roller surface, making it difficult to remove the rubber residue.

  Moreover, release agents generally have a low molecular weight and are poor in heat resistance. In many cases, the release agent decomposes at a temperature lower than the secondary vulcanization temperature and is thermally denatured into an acidic substance or an alkaline substance. Silicone rubber is vulnerable to acids and alkalis, and therefore, there is a problem that the surface is eroded if secondary curing is performed with the release agent attached to the surface of the elastic layer. In order to overcome this problem, it is preferable to reduce the release agent as much as possible. However, if the release agent is reduced, it is difficult to apply thinly and uniformly while ensuring the releasability.

  Here, in order to be used as various rollers of an image forming apparatus, surface processing is often performed as necessary after secondary curing. If the silicone rubber residue adhering to the roller surface (elastic layer surface) is not removed when the surface is processed, convexes derived from the silicone rubber residue are formed on the roller surface, which causes image defects. Further, when the roller surface (elastic layer surface) is eroded by the heat-modified product of the release agent, the roller surface is recessed by erosion, which causes an image defect. In view of this, there has been proposed an apparatus for washing the elastic layer surface of the elastic roller with water under high pressure in order to remove rubber burrs and release agents on the roller surface (Patent Document 1). However, the water cleaning requires a drying process for surface processing, which makes the production apparatus complicated and expensive.

In recent years, a roller used in an image forming apparatus is required to eliminate erosion caused by a very small rubber residue and a heat-modified product of a release agent on the roller surface in order to form a highly accurate image. On the other hand, there is a demand for cost reduction of production equipment.
Japanese Patent Laid-Open No. 2005-230662

  That is, the present invention has been made in view of the above problems, and in a method for producing a roller by curing silicone rubber, the roller surface has no protrusions derived from silicone rubber residue, and further, a heat-modified product of a release agent. An object of the present invention is to provide a highly accurate roller manufacturing method in which the roller surface is not corroded.

  The object of the present invention is achieved by the following.

That is, the present invention relates to a method of manufacturing a roller in which a mold release agent is applied to the inner surface of a cylindrical mold, a cored bar is arranged, liquid silicone rubber is injection-molded concentrically with the cored bar, and is cured and molded. Because
The roller manufacturing method is characterized in that the roller removed from the primary curing process is brought into contact with the adhesive tape before the secondary curing process.

  Furthermore, the present invention is a developing roller for applying a developer to an image carrier on which a latent image is formed, the developing roller being manufactured by the above manufacturing method.

  Furthermore, the present invention is an image forming apparatus equipped with a developing roller for applying a developer to an image carrier on which a latent image is formed, wherein the developing roller is the above-described developing roller. An image forming apparatus.

  ADVANTAGE OF THE INVENTION According to this invention, the roller surface does not have the convexity derived from a silicone rubber residue, Furthermore, the manufacturing method of a highly accurate roller with which the roller surface by the heat modified material of a mold release agent is not eroded is provided.

  Hereinafter, embodiments of the present invention will be described in detail.

  In the method for producing a roller of the present invention, after a release agent is applied to the inner surface of a cylindrical mold, a core metal is disposed in the cylindrical mold, and liquid silicone rubber is injection-molded concentrically with the core metal and cured. The method of manufacturing the roller to be molded. The roller removed from the primary curing process is brought into contact with the adhesive tape before the secondary curing process. The adhesive strength of the adhesive tape is preferably 1.0 N / 10 mm or more and 10.0 N / 10 mm or less.

  A cross-sectional view of an example of the conductive roller of the present invention is shown in FIG. In FIG. 1, (a) is a view taken along the center line of the shaft core of the conductive roller, and (b) is a view of the conductive roller viewed from the center line direction of the core metal.

  The conductive roller 1 includes a conductive core 2, a conductive elastic layer 3 concentrically formed on the outer periphery of the core 2, and a coating layer formed on the outer periphery of the conductive elastic layer 3. 4.

[Core]
As the metal core 2, for example, a carbon steel alloy surface having a conductive nickel column shape having a chemical nickel plating thickness of 5 μm is preferable. As a material of the core metal, for example, metals such as iron, aluminum, titanium, copper, and nickel, alloys such as stainless steel, duralumin, and bronze containing these metals, and composite materials obtained by solidifying carbon black and carbon fibers with plastics, etc. Rigid and conductive materials can also be used. Moreover, as a shape of the metal core 2, it is also possible to make it cylindrical shape which made the center part a cavity.

(Cylindrical mold)
The cylindrical mold used in the present invention is preferably made of steel and at least the cavity wall surface is surface-treated. Examples of the surface treatment include surface treatment by a chemical nickel plating method, a Teflon coating method, a gas nitriding method, a salt bath nitriding method, a gas soft nitriding method, a plasma nitriding method, and the like. It can be selected appropriately.

〔Release agent〕
In the present invention, a release agent is applied to the cavity wall surface of the mold. As the release agent, a general release agent is used, and examples thereof include a fluorine release agent, a silicone release agent, and a surfactant.

  There is no restriction | limiting in particular as an organic fluorine compound used as a fluorine-type mold release agent, It can use suitably selecting from conventionally well-known various fluorine-type compounds. For example, perfluorocarboxylic acids such as perfluoroacetic acid and perfluorobutyric acid and perfluorocarboxylic acid salts thereof such as lithium salt, sodium salt or potassium salt; fluoroalkyl (C2 to C10) carboxylic acid and salts thereof; Perfluorocarboxylic acid alkyl esters such as acid methyl ester, ethyl ester, propyl ester, and butyl ester; fluoroalkyl (C2 to C10) carboxylic acid alkyl ester; polymer of perfluoroalkyl acrylate or methacrylate, or butyl acrylate with these , Copolymers with butyl methacrylate, stearyl acrylate, stearyl methacrylate and the like.

  There is no restriction | limiting in particular as a silicone type mold release agent, It can select from the conventionally well-known various silicone oils, and can use it suitably. Examples of the silicone oil that can be used as the silicone release agent in the present invention include polysiloxane having an alkyl group, a phonyl group, or a fluoroalkyl group in the side chain. Two or more of these silicone oils may be used in combination as desired. These silicone oils may contain additives such as silicone resins.

As the surfactant release agent, a compound having an anionic surface activity is preferable, and the following can be mentioned.
(1) A sulfonate organic compound which is a salt of IA, IIA or IIB metal of sulfonic acid.
(2) A sulfate ester organic compound which is a salt of an IA, IIA or IIB metal of an ester of sulfuric acid and alcohol.
(3) A phosphate ester salt organic compound which is a salt of a phosphate ester IA, IIA or IIB metal.

  Among these, sulfate ester organic compounds are particularly preferable.

The release agent used in the present invention is usually used after being dissolved or dispersed in an organic solvent or an aqueous medium. Examples of the organic solvent or aqueous medium include the following, and these may be used alone or in admixture of two or more.
-Alcohols such as methanol, ethanol, propanol, isopropanol;
-Ketones such as acetone and methyl ethyl ketone;
-Ethers such as ethyl ether, isopropyl ether, dioxane, tetrahydrofuran;
-Esters such as ethyl acetate and butyl acetate;
・ Hydrocarbons such as hexane, cyclohexane, toluene, xylene;
-Halogenated hydrocarbons such as carbon tetrachloride, methylene chloride, trichloroethylene, perchlorethylene, trichloroethane, trichlorofluoromethane, tetrachlorodifluoroethane, trichlorotrifluoroethane;
And water.

  In order to apply the release agent to the cavity wall surface (also referred to as the inner surface of the mold) of the mold, a known method can be used. For example, a method in which a mold is immersed in a solution or dispersion of a mold release agent, a solution or dispersion of a mold release agent is sprayed or brushed on the cavity wall surface of the mold, or a cloth is soaked in a cloth. For example, there is a method in which the organic solvent or water is removed by evaporation.

  The release agent to be used can be appropriately determined according to the material of the conductive elastic layer and the material constituting the cavity wall surface of the mold.

[Conductive elastic layer]
The material for the conductive elastic layer of the conductive roller in the present invention is appropriately selected from known materials. The degree of elasticity is appropriately determined according to the purpose of use. The degree of conductivity is also appropriately determined according to the purpose of use. In the electroconductive elastic roller used in the electrophotographic process, as a material constituting the electroconductive elastic layer, a liquid rubber raw material, preferably a liquid addition reaction cross-linked silicone polymer blended with a conductive filler such as carbon black is preferable.

[Liquid silicone rubber raw material]
The material constituting the conductive elastic layer in the present invention is excellent in heat resistance and cold resistance, exhibits a good compression recovery property in a wide temperature range, and has weather resistance, ozone resistance, corona resistance, electrical characteristics, heat resistance oil resistance, A material excellent in chemical properties, hot water resistance and the like is preferable. These characteristics can be determined by the type and blending method of the silicone polymer, filler, additive and the like blended in the liquid silicone rubber raw material for obtaining the material constituting the conductive elastic layer in the present invention.

  The silicone polymer contains an organopolysiloxane and an organohydropolyene polysiloxane, and is used as a liquid rubber raw material by appropriately mixing with an inorganic filler, a platinum-based catalyst, and a curing reaction retarder.

  The organopolysiloxane has a linear structure or a branched structure, and is used as a base polymer of a liquid silicone rubber raw material. The liquid rubber material for forming the elastic layer of the conductive roller in the present invention preferably contains an organopolysiloxane. The molecular weight is not particularly limited, but is preferably from 100,000 to 1,000,000, and the weight average molecular weight is preferably about 500,000. Furthermore, from the viewpoints of processing characteristics and characteristics of the obtained liquid rubber raw material, the viscosity of the organopolysiloxane at 25 ° C. is preferably 10 Pa · s or more, and more preferably 50 Pa · s or more. Moreover, 300 Pa * s or less is preferable from workability, and 250 Pa * s or less is more preferable. It is preferable that the viscosity of the organopolysiloxane is 10 Pa · s or more because the fluidity of the liquid rubber raw material is small and it is difficult to leak. In addition, when the viscosity of the organopolysiloxane is 300 Pa · s or less, a liquid rubber raw material which is difficult to bite is obtained, which is preferable.

  The molecular end group of the organopolysiloxane is a site that reacts with the active hydrogen of the organohydrogenpolysiloxane to form a crosslinking point. Although the kind of molecular terminal group is not specifically limited, A triorganosilyl group, for example, a trimethylsilyl group, a diphenylmethylsilyl group, a diphenylallylsilyl group, a dimethylvinylsilyl group, a methylphenylvinylsilyl group etc. can be illustrated. For reasons such as high reactivity with active hydrogen, a triorganosilyl group containing at least one of a vinyl group and an allyl group is preferred, and a triorganosilyl group containing a vinyl group is particularly preferred.

  The organohydrogenpolysiloxane has at least two hydrogen atoms directly bonded to silicon atoms in one molecule. This is to form a crosslink by an addition reaction between the hydrogen atom and the alkenyl group in the organopolysiloxane and cure the liquid rubber raw material containing them. The liquid silicone rubber raw material for forming the elastic layer of the conductive roller in the present invention preferably contains polyorganohydrodiene polysiloxane. There is no restriction | limiting in particular in the molecular weight of polyorganohydrodiene polysiloxane, and what is 1000-10000 is preferable. In order to appropriately perform the curing reaction of the liquid rubber raw material, polyorganohydrodiene polysiloxane having a relatively low molecular weight (1000 to 5000) is preferable.

  The viscosity of the liquid silicone rubber raw material containing a silicone polymer blended with the necessary filler and the like is not particularly limited, but is 10 Pa · s or more from the viewpoint of preventing leakage by suppressing the fluidity of the liquid rubber raw material to some extent. Is preferred. Moreover, it is preferable that it is 300 Pa * s or less from a viewpoint for avoiding the problem of moldability, such as generation | occurrence | production of a weld between injection gates in the formed conductive elastic layer.

  The conductive elastic layer is subjected to primary curing by injecting the liquid silicone rubber raw material into a cavity in a cylindrical mold on which a release agent is applied with a shaft core. Generally, as primary curing conditions, heating and curing are performed at a temperature of 100 ° C. to 150 ° C. for 3 to 60 minutes. In this case, the primary curing means that the conductive elastic forming material is cured to such an extent that the conductive elastic layer can be taken out from the cylindrical mold without significantly losing its shape, and further the curing in the cylindrical mold. This means that the rubber is cured within a range that does not cause the elastic layer to break. After this primary curing treatment, a roller having a conductive elastic layer formed around the core metal is taken out of the mold (demolding), and further heat treatment is performed to increase the curing of the conductive elastic layer and the stability of physical properties. (Secondary curing treatment). In general, as the secondary curing treatment conditions, heating and curing are performed at a temperature of 180 ° C. to 220 ° C. for 0.5 to 6 hours. In the present invention, prior to the secondary curing treatment, the roller surface is brought into contact with the adhesive tape, and the silicone rubber residue and the release agent that erodes the roller surface by heat denaturation are removed.

[Removal of silicone rubber residue]
The method for removing the silicone rubber residue and the release agent that erodes the roller surface by heat denaturation in the present invention is a method of removing the roller surface with an adhesive tape.

  The pressure-sensitive adhesive tape may be a general one, and examples thereof include craft tape, cloth tape, and OPP (stretched polypropylene film) tape. In removing the silicone rubber residue on the roller surface and the release agent that erodes the roller surface due to thermal denaturation, it is preferable that the adhesive of the adhesive tape does not migrate to the roller surface.

  These adhesive tapes consist of a support and an adhesive. Examples of the support include paper, cloth, and plastic film. Examples of paper include craft paper, Japanese paper, and crepe paper. Examples of the cloth include woven cloth such as rayon, cotton, acetate, glass, polyester, vinylon alone or blended cloth, split cloth such as polyethylene and polypropylene, and non-woven cloth such as rayon, polypropylene, aromatic polyamide, polyester and glass. . Examples of the plastic film include films of cellophane, acetate, polyvinyl chloride, polyethylene, polypropylene, polyester, polytetrafluoroethylene, and polyimide.

  Examples of the adhesive include rubber-based, acrylic-based, and silicone-based adhesives. Examples of rubbers include natural rubbers, styrene-butadiene rubbers, isobutylene rubbers, isoprene rubbers, styrene-isoprene block copolymers, styrene-butadiene block copolymers, and the like. As an acrylic type, it is a copolymer of one or more types of acrylic acid C4-C9 alkyl ester and a vinyl monomer. The silicone system is a 100% silicone composition composed of silicone rubber and silicone resin.

  The adhesive strength of the adhesive tape is preferably 1.0 N / 10 mm or more and 10.0 N / 10 mm or less. The method for measuring the adhesive strength is in accordance with the measurement of the adhesive strength by peeling off 180 degrees in the test method for the adhesive tape / adhesive sheet of JIS-Z0237. When the adhesive strength is 1.0 N / 10 mm or more, the adhesive strength of the silicone rubber residue on the roller surface is superior, and the silicone rubber residue can be removed from the roller surface. A release agent that erodes the roller surface by heat denaturation from the roller surface without breaking the conductive elastic layer due to the adhesive force between the adhesive tape and the roller surface when the adhesive force is 10.0 N / 10 mm or less Can be removed.

  As a means to remove silicone rubber residue from the roller surface and the release agent that erodes the roller surface by heat denaturation, press the roller surface against the adhesive surface of the adhesive tape and rotate the roller around the horizontal axis for at least one turn. Move back and forth. The force for pressing the roller surface against the adhesive surface of the adhesive tape is suitably from 0.01 MPa to 1 MPa. If the pressure is less than 0.01 MPa, the adhesive force between the adhesive tape and the silicone rubber residue or the release agent that erodes the roller surface due to heat denaturation is weak, and the silicone rubber residue from the roller surface and the release agent that erodes the roller surface due to heat denaturation are present. It may be insufficient. If it is greater than 1 MPa, the conductive elastic layer may be deformed, or silicone rubber residue or a release agent may be eroded into the conductive elastic layer. The number of rotations rotated around the horizontal axis of the roller is suitably from 1 rpm to 300 rpm. If it is slower than 1 rpm, the silicone rubber residue and the release agent that erodes the roller surface due to thermal denaturation can be removed, but the tact time becomes large and unsuitable for production. On the other hand, if it is faster than 300 rpm, the silicone rubber residue and the release agent that erodes the roller surface due to thermal denaturation may be insufficient, or the adhesive of the adhesive tape may move to the roller surface.

(Coating layer)
In the present invention, a coating layer is formed on the outer periphery of the conductive elastic layer formed as described above. The coating layer is preferably made of a material containing, for example, a fluororesin, a nylon resin, an acrylic resin, a polyurethane resin, or the like in order to meet demands such as wear resistance, toner chargeability, and toner transportability. When the conductive roller is a developing roller, the coating layer is preferably made of a material containing a polyurethane resin from the viewpoint of compression set.

  As a polyol compound as a raw material of the polyurethane resin, it can be appropriately selected from known polyols for polyurethane. For example, polyethylene glycol, tetramethylene glycol, polyethylene diadipate, polyethylene butylene adipate, poly-ε-caprolactone diol, polycarbonate polyol, polypropylene glycol and the like can be mentioned.

  Also, the isocyanate compound as one raw material can be appropriately selected from known polyurethane isocyanate compounds. Specific examples include diisocyanates such as diphenylmethane diisocyanate (MDI), tolylene diisocyanate (TDI), hexamethylene diisocyanate (HDI). Moreover, those burette modified bodies, isocyanurate modified bodies, urethane modified bodies, etc. can also be mentioned. Particularly preferred are HDI and its burette modified products, isocyanurate modified products, urethane modified products and the like. The longer the molecular chain of the isocyanate compound, the more flexible polyurethane coating layer can be produced.

  For the purpose of adjusting the electrical resistance of the entire conductive roller, the covering layer can be made conductive or semiconductive. In order to achieve conductivity and semiconductivity, a conductive agent having an electron conduction mechanism or a conductive agent having ionic conductivity is used. Examples of the conductive agent having an electron conduction mechanism include carbon black, graphite, conductive metal oxide, copper, aluminum, nickel, and iron powder. Examples of the conductive agent having ionic conductivity include alkali metal salts and ammonium salts. In order to obtain desired conductivity, two or more of these conductive agents may be used in combination.

  The coating layer is preferably formed by applying a coating material for forming a coating layer on the outer periphery of the conductive elastic layer, drying it to form a coating layer, and further heating and curing the coating layer. The coating material for forming the coating layer can be prepared by dispersing the raw materials using a conventionally known dispersing device using beads such as a sand mill, a paint shaker, a dyno mill, and a pearl mill. The coating for forming the coating layer can be applied by a spray coating method, a dipping method, or the like.

An organic solvent may be used for preparing the coating material for forming the coating layer. Examples of the organic solvent that can be used in the present invention include the following.
-Ketones such as methyl isobutyl ketone, methyl ethyl ketone, acetone, cyclohexanone,
・ Aromatics such as xylene and toluene,
-Esters such as n-butyl acetate and ethyl acetate,
-Ethers such as tetrahydrofuran, ethyl cellosolve, and tetrahydropyran.

  The organic solvent is preferably one that does not dissolve the conductive elastic layer formed in the previous step. In addition, when the material which comprises a conductive elastic layer melt | dissolves, you may use the solvent containing water and water.

  The thickness of the coating layer is preferably 5 μm to 100 μm, particularly preferably 10 μm to 30 μm. If the layer thickness is too thin, low molecular weight components in the conductive elastic layer of the base layer may ooze out and contaminate the photoreceptor or the like. On the other hand, if the thickness is too thick, the conductive roller becomes hard. For example, when a developing roller is used, it causes toner fusion, which is not preferable.

  By dispersing fine particles having an average particle diameter of 1 μm to 20 μm in the coating layer, when the conductive roller is a developing roller, the toner can be easily conveyed, and a sufficient amount of toner can be applied to the developing region. Can be transported. Examples of the fine particles used for such purposes include resin fine particles such as polymethyl methyl methacrylate fine particles, silicone rubber fine particles, polyurethane fine particles, polystyrene fine particles, and amino resin fine particles. Particularly preferred are polymethyl methyl methacrylate fine particles, silicone rubber fine particles and polyurethane fine particles. These fine particles are usually preferably added in the range of 3% to 50% by mass of the material constituting the coating layer.

[Image forming apparatus]
Next, an example of an image forming apparatus equipped with a process cartridge using the conductive roller of the present invention as a developing roller will be described with reference to the drawings.

  FIG. 2 is a diagram showing a schematic configuration of an image forming apparatus equipped with a process cartridge using the conductive roller of the present invention as a developing roller.

  The process cartridge includes a developing roller 25 as a developer carrying member that carries the developer 28 in a state of being in contact with or pressed against the photosensitive drum 21 as an image carrier that carries a latent image. The developing roller 25 applies toner 28 as a developer to the photosensitive drum 21 to visualize the latent image as a developer image. The process cartridge includes a photosensitive drum 21, a charging device 22, a developer carrying member 25, a developing blade 27, a developing container 34, and a cleaning blade 30, and using the conductive roller of the present invention as the developer carrying member 25. It is. Here, the photosensitive drum 21 rotates in the direction of arrow A, is uniformly charged by a charging device 22 for charging the photosensitive drum 21, and is a laser beam 23 that is an exposure means for writing an electrostatic latent image on the photosensitive drum 21. As a result, an electrostatic latent image is formed on the surface. The electrostatic latent image is developed by being provided with toner 28 by the developing device 24 that is disposed in the vicinity of the photosensitive drum 21 and is held in the process cartridge that can be attached to and detached from the image forming apparatus main body. Visualized.

  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 sent to the fixing device 32, where it is fixed, 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 is repeatedly subjected to the above-described operation.

  The developing device 24 includes a developing container 34 that contains a non-magnetic toner 28 as a one-component developer, and a conductive container according to the present invention that is located at an opening extending in the longitudinal direction in the developing container 34 and is opposed to the photosensitive drum 21. The roller is provided as a developing roller. The developing device 24 develops and visualizes the electrostatic latent image on the photosensitive drum 21.

  The developing roller 25 is in contact with the photosensitive drum 21 with a contact width and is rotated in the arrow B direction. In the developing device 24, the supply roller 26 is in contact with the contact portion of the developing blade 27 with the surface of the developing roller 25 in the developing container 34 on the upstream side in the rotation direction of the developing roller 25 and is rotatable. It is supported.

  As the structure of the supply roller 26, a foamed skeleton-like sponge structure or a fur brush structure in which fibers such as rayon or nylon are planted on a core metal is used for supplying toner to the developing roller 25 and stripping off undeveloped toner. To preferred. In the present embodiment, a supply roller 26 having a diameter of 14 mm in which a polyurethane foam is provided on a core metal is used.

  The contact width of the supply roller 26 with respect to the developing roller 25 is appropriately 1 mm to 8 mm. The developing roller 25 preferably has a relative speed at the abutting portion. In this embodiment, the abutting width is set to 2 mm, and the developing roller 25 is rotated at a predetermined timing by a driving unit (not shown). Driven.

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

<Example 1>
As the mold, a cylindrical mold in which a nickel-plated cavity wall surface is nitrided is used. Moreover, the fluorine-type mold release agent (Flease (brand name): Neos Co., Ltd.) was used as a mold release agent.

The release agent described above was applied to the wall surface of the cylindrical mold cavity, and an axial core body having a diameter of 8 mm was placed concentrically in the mold cavity. Next, liquid conductive silicone rubber (manufactured by Toray Dow Corning Co., Ltd., volume resistivity 10 × 10 ⁷ Ω · cm product) is injected at 10 cc / s from the mold inlet and heated at a temperature of 100 ° C. for 10 minutes. Then, it was first cured, removed from the mold without cooling after curing, and an elastic roller was produced. The obtained elastic roller has a conductive elastic layer formed on the outer peripheral surface of the shaft body. The diameter of the portion where the conductive elastic layer is formed is approximately 16 mm, and the conductive elastic layer is formed. The length of the site was 240 mm.

  Next, a kraft tape (Sekisui Chemical Co., Ltd., craft tape No. 500, width 250 mm) having an adhesive strength of 3.3 N / 10 mm was used as the adhesive tape, and the roller was pressed against the adhesive tape at 0.1 MPa. The roller was rotated around the horizontal axis at 60 rpm, and the three rollers were reciprocated three times. In this way, the silicone rubber residue and the release agent on the surface of the elastic roller were removed.

  Thereafter, the roller is heat-treated in an oven at 200 ° C. for 4 hours for the purpose of stabilizing the physical properties of the conductive elastic layer after curing and removing reaction residues and unreacted low molecular components in the silicone rubber elastic layer. (Secondary curing) was performed.

  Urethane paint “Nipporan N5033” (trade name, manufactured by Nippon Polyurethane Co., Ltd.) was diluted with methyl ethyl ketone so as to have a solid content concentration of 10%. To this, 50 parts by mass of carbon black “# 7360SB” (trade name, manufactured by Tokai Carbon Co., Ltd.) was added with respect to 100 parts by mass of the solid content of the urethane paint, and was sufficiently dispersed. Next, 10 parts by mass of a curing agent “Coronate L” (trade name, manufactured by Nippon Polyurethane Co., Ltd.) is added to 100 parts by mass of the solid content of the urethane paint, and further diluted with 200 parts by weight of methyl ethyl ketone, stirred and coated. A forming paint was prepared.

  Next, the coating material is dipped on the outer peripheral surface of the conductive elastic layer of the secondary-cured roller, dried in an oven at 80 ° C. for 15 minutes, and then cured in an oven at 140 ° C. for 4 hours. A coating layer having a thickness of about 20 μm was formed to obtain a developing roller.

  The obtained developing roller was visually observed, and the results are shown in Table 1.

<Example 2>
A developing roller was produced in the same manner as in Example 1 except that a surface protective tape having an adhesive strength of 1.0 N / 10 mm (manufactured by Nitto Denko, SPV-C-400, width 250 mm) was used as the adhesive tape. The obtained results are shown in Table 1.

<Example 3>
A developing roller was produced in the same manner as in Example 1 except that a cloth tape (manufactured by Teraoka Seisakusho, P-cut tape No. 417, width 250 mm) having an adhesive strength of 8.0 N / 10 mm was used as the adhesive tape. The obtained results are shown in Table 1.

<Comparative Example 1>
In Example 1, after the primary curing, the silicone rubber residue and the release agent were not removed by the adhesive tape, and the secondary curing treatment was performed immediately after the demolding to produce a developing roller. The obtained results are shown in Table 1.

<Comparative Example 2>
After the primary curing, the silicone rubber residue and the release agent are not removed by the adhesive tape, and after the mold removal, the secondary curing treatment is performed immediately. , Kraft tape No. 500, width 250 mm), the roller was pressed against the adhesive tape at 0.1 MPa, the roller was rotated at 60 rpm around the horizontal axis, and the three rounds of the roller were reciprocated three times. A developing roller was produced in the same manner as in Example 1. The obtained results are shown in Table 1.

[Rubber residue convexity evaluation method]
Under each condition, 1000 rollers were produced, and the presence or absence of protrusions derived from rubber residue was judged visually, and the number was counted.

[Dent evaluation method]
Under each condition, 1000 rollers were prepared, and the presence or absence of dents derived from the heat-modified product of the release agent was judged by visual observation, and the number was counted.

  As is apparent from the results shown in Table 1, the development rollers of Examples 1, 2, and 3 were brought into contact with the pressure-sensitive adhesive tape after the primary curing, so that the rubber residue on the roller and the release agent heat-denatured dent were generated. A roller with low accuracy and high accuracy was obtained. On the other hand, in the developing rollers of Comparative Examples 1 and 2, since the silicone rubber residue and the release agent were not removed by the adhesive tape after the primary curing, the silicone rubber residue and the release agent remained on the roller, and the rubber residue and convexity were separated. Mold heat denaturation dents occurred frequently.

It is sectional drawing of one Embodiment of the conductive roller which this invention makes object. 1 is a schematic configuration diagram of an embodiment of an image forming apparatus of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Conductive roller 2 Shaft core body 3 Conductive elastic layer 4 Cover layer 21 Photosensitive drum 22 Charging device 23 Laser beam 24 Developing device 25 Developing roller 26 Supply roller 27 Developing blade 28 Toner (developer)
29 Transfer roller 30 Cleaning blade 31 Waste toner container 32 Fixing device 33 Paper 34 Developer container

Claims (4)

A method for manufacturing a roller in which a mold release agent is applied to the inner surface of a cylindrical mold, a core metal is disposed in the cylindrical mold, liquid silicone rubber is injection-molded concentrically with the core metal, and is cured and molded Because
A roller manufacturing method, wherein a roller removed from a mold after the primary curing process is brought into contact with an adhesive tape before the secondary curing process.   The method for producing a roller according to claim 1, wherein the adhesive strength of the adhesive tape is 1.0 N / 10 mm or more and 10.0 N / 10 mm or less.   A developing roller for applying a developer to an image bearing member on which a latent image is formed, the roller being manufactured by the manufacturing method according to claim 1 or 2.   An image forming apparatus comprising a developing roller for applying a developer to an image carrier on which a latent image is formed, wherein the developing roller is the developing roller according to claim 3. .

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