JP4986214B2 - Manufacturing method of conductive roller - Google Patents

Description

The present invention relates to a method for producing a conductive roller, and more particularly, for example, can be used in an image forming apparatus, a method of manufacturing a conductive roller that contribute to the formation of high quality images.

  Various types of image forming apparatuses using an electrophotographic system are employed in laser printers, copiers, video printers, facsimiles, and complex machines of these. An image forming apparatus using an electrophotographic system includes a shaft body and an elastic layer formed on an outer peripheral surface thereof, for example, a cleaning roller, a charging roller, a developing roller, a transfer roller, a pressure roller, a paper feed conveyance roller, Various rollers such as a fixing roller are provided. In such an image forming apparatus, in order to form a high-quality image, various rollers mounted on the image forming apparatus need to have high uniformity.

  Conventionally, these various rollers have been manufactured by subjecting the outer peripheral surface of a molded body formed by molding a rubber composition to the outer peripheral surface of a shaft body, etc. according to a standard method. Further, in this manufacturing method, if the molded body is subjected to a polishing treatment or the like, the productivity is lowered and the cost is increased, so that the molded body has a desired outer diameter without being subjected to a polishing treatment or the like. A manufacturing method capable of manufacturing a roller has also been proposed. As an example thereof, for example, in a method of manufacturing a roller in which a liquid rubber composition is injected into a cylindrical mold and heat-molded, the dimensional accuracy of the cylindrical mold to be used is improved and / or heating during the heat-molding is performed. Examples thereof include a method for adjusting the temperature and the like, a method for adjusting the pressure in the mold (for example, see Patent Document 1), and the like. For example, according to the method for manufacturing a rubber roller described in Patent Document 1, “the outer diameter accuracy of the rubber roller can be stably molded, and a high-quality rubber roller can be provided at a low cost”. (Refer to [0075] column of Patent Document 1).

  However, recent image forming apparatuses have rapidly developed higher image quality and the like, and high-speed performance has been remarkably improved, so that they can be mounted on recent image forming apparatuses in addition to conventional image forming apparatuses. Various rollers are required to have higher uniformity. In addition, when a molded body formed by molding a rubber composition is not subjected to a polishing treatment or the like, various rollers having high uniformity are generally difficult to manufacture.

Japanese Patent Laid-Open No. 2003-039542

  The present invention relates to a conductive roller that contributes to the formation of a high-quality image, a method for producing a conductive roller that can produce a conductive roller that contributes to the formation of a high-quality image, and a high quality An object of the present invention is to provide an image forming apparatus capable of forming the image.

As means for solving the problems,
Claim 1 is a method of manufacturing a conductive roller comprising a shaft body and a polishing-less elastic layer formed on an outer peripheral surface thereof, and disposed in an image forming apparatus. The vulcanization characteristic X corresponding to the desired outer diameter of the liquid is calculated, a liquid conductive rubber composition having a vulcanization characteristic with the calculated X value ± 10 is prepared, and then the liquid conductive rubber composition is made of gold. A method for producing a conductive roller, wherein the mold is injected into a cavity formed by a mold and the shaft body held by the mold, and is heat-molded .
Y = aX + b
(Where, a is −0.0046 to −0.0026, b is 20.07 to 20.14, Y is the outer diameter (unit: mm) of the polishing-less elastic layer, and X is the vulcanization characteristic tc. (10) is shown.)
Claim 2 is the method for producing a conductive roller according to claim 1 , wherein the liquid conductive rubber composition is an addition curable liquid conductive silicone rubber composition .
A third aspect of the present invention is the method for manufacturing a conductive roller according to the first or second aspect , wherein the coating layer forming material applied to the outer peripheral surface of the polishingless elastic layer is cured and / or vulcanized. Yes,
A fourth aspect of the present invention is characterized in that the polishingless elastic layer has an outer diameter accuracy within a range of ± 0.25% and a runout of 0.5% or less. 2. A method for producing a conductive roller according to item 1.

  The conductive roller according to the present invention includes a polishingless elastic layer having an outer diameter accuracy within a range of ± 0.25% and a thickness fluctuation of 0.5% or less. Not only the image forming apparatus but also a recent image forming apparatus, it is in contact with a contacted body such as an image carrier uniformly at a predetermined pressure and over the longitudinal direction of the conductive roller. Therefore, since the conductive roller according to the present invention can act uniformly on the contacted body in the longitudinal direction, the conductive roller can sufficiently contribute to forming a high-quality image. For example, when the conductive roller according to the present invention is used as a developing roller disposed so as to come into contact with an image carrier provided in a recent image forming apparatus, the conductive roller at a predetermined pressure is used. Can contact the image carrier uniformly in the longitudinal direction of the toner, and the developer can be adhered to the image carrier with a uniform thickness with high accuracy, thereby contributing sufficiently to the formation of a high-quality image. it can.

  Further, the method for producing a conductive roller according to the present invention includes selecting a liquid conductive rubber composition having a vulcanization characteristic tc (10) that greatly depends on the outer diameter accuracy of the conductive roller in the liquid injection molding method. Therefore, a polishing-less elastic layer having a desired outer diameter can be molded while sufficiently satisfying high outer diameter accuracy and small runout. Therefore, according to the method for manufacturing a conductive roller according to the present invention, as described above, a high-resistance polishing layer having a desired outer diameter and having a high outer diameter accuracy and a small runout is provided. Conductive rollers that contribute to forming quality images can be manufactured.

  Furthermore, since the image forming apparatus according to the present invention includes the conductive roller according to the present invention or the conductive roller manufactured by the method for manufacturing the conductive roller according to the present invention, a high-quality image is formed. can do.

  As shown in FIG. 1, the conductive roller according to the present invention is a polishing-less elastic material obtained by heat-molding a liquid conductive rubber composition using a mold on the outer periphery of the shaft body 2 and the shaft body 2. 2 and, if desired, as shown in FIG. 2, further includes a coat layer 4 and is disposed in, for example, the image forming apparatus shown in FIG.

  The shaft body 2 only needs to have good conductive properties, and is usually a so-called “core” made of iron, aluminum, stainless steel, brass, or the like. Further, the shaft body 2 may be a shaft body that is made conductive by plating an insulating core body such as a thermoplastic resin or a thermosetting resin. Furthermore, the shaft body 2 may be a thermoplastic resin or a thermosetting resin. The shaft body may be formed of a conductive resin in which carbon black or metal powder is blended as a conductivity imparting agent. When the shaft body 2 is disposed in the image forming apparatus or the like shown in FIG. 6, one end of the shaft body 2 is grounded or a bias voltage is applied, for example, the voltage of the image carrier, It performs functions such as charge injection and development of a latent image by conveying developer from the image carrier.

  The polishing-less elastic layer 3 is formed by, for example, heat-molding a liquid conductive rubber composition in which a conductivity imparting agent or the like is added to a rubber component, and the molded body is subjected to an external treatment such as polishing, grinding, and cutting. It is made without performing diameter adjustment processing. Therefore, the polishing-less elastic layer 3 has an outer diameter accuracy within a range of ± 0.25% and a runout of 0.5% or less in a heat-molded state.

  As described above, the polishing-less elastic layer 3 has an outer diameter accuracy within a range of ± 0.25%. The outer diameter accuracy of the polishing-less elastic layer 3 is an accuracy that is uniform in the longitudinal direction and has a desired outer diameter. When the polishing-less elastic layer 3 has an outer diameter accuracy within this range, as will be described later, for example, when it is disposed in the image forming apparatus shown in FIG. 6, a high-quality image is formed. Can contribute enough to. The outer diameter accuracy is preferably within a range of ± 0.14% and can be within a range of ± 0.10% in that it can sufficiently contribute to forming a higher quality image. Is particularly preferred.

The accuracy of the outer diameter of the polishing-less elastic layer 3 is determined by measuring the outer diameter at least at three points of the central portion and the vicinity of both ends of the polishing-less elastic layer 3 and obtaining the measured outer diameter. to the average outer diameter of the _{(r av),} a value showing an outer diameter difference of _(r x _{-r av)} as a percentage of the outside diameter _{(r x)} and the average outer diameter _{(r av)} at each measurement point, specifically Specifically, at each measurement point, it is calculated by the formula [(r _x −r _av ) / r _av ] × 100 (%) Here, the outer diameter accuracy of the polishing-less elastic layer 3 is calculated from the measured outer diameters according to the above formula by measuring the outer diameter at the measurement point of the polishing-less elastic layer 3 with a laser measuring instrument in accordance with a standard method. Can do.

  As described above, the polishing-less elastic layer 3 has a deflection of 0.5% or less. The wobbling of the polishing-less elastic layer 3 is an accuracy showing the uniformity of the thickness in the circumferential direction of the polishing-less elastic layer, that is, the thickness wobbling (hereinafter sometimes simply referred to as wobbling). When the polishing-less elastic layer 3 has a shake in this range, as will be described later, for example, when it is disposed in the image forming apparatus shown in FIG. 6, a high-quality image is formed. You can contribute enough. The shake is preferably 0.4% or less, and particularly preferably 0.3% or less, in that it can sufficiently contribute to forming a higher quality image. Note that the vibration of the polishing-less elastic layer 3 is ideally 0, but actually, it slightly differs at each position in the axial direction of the shaft body 2. The lower limit of the deflection in the polishing-less elastic layer 3 may be about 0.002% to achieve the object of the present invention, and about 0.001% to sufficiently achieve the object of the present invention. Good.

The vibration of the polishing-less elastic layer 3 is affected by the distance between the center point 3C of the polishing-less elastic layer 3 and the center point 2C of the shaft body 2. For example, as shown in FIG. 7 (a), the conductive roller 1C has an outer peripheral surface of the shaft body 2 in which the axis 2C of the shaft body 2 is shifted from the axis thereof in the axial direction. FIG. 7B shows a cross section taken along the line AA of the conductive roller 1C. Referring to FIG. 7, the wobbling of the polishing-less elastic layer 3B is the difference (t _max -t _min ) between the maximum thickness (t _max ) and the minimum thickness (t _min ) of the polishing-less elastic layer 3B, in other words, The difference (L ₂ −L ₁ ) between the longest distance L ₂ and the shortest distance L ₁ from the center point 2C of the shaft body 2 to the outer peripheral surface of the polishing-less elastic layer 3B is defined as the average outer diameter (r calculated as a percentage of _av ).

That is, the wobbling of the polishing-less elastic layer 3 is at least at three points of the central portion and the vicinity of both ends of the polishing-less elastic layer 3 with respect to the average outer diameter (r _av ) of the polishing-less elastic layer 3. 3 is a value indicating the difference (t _max −t _min ) between the maximum thickness (t _max ) and the minimum thickness (t _min ) of 3 and more specifically, at each measurement point, the equation [ (T _max −t _min ) / r _av ] × 100 (%) Alternatively, the polishing-less elastic layer 3 from the center point 2C of the shaft body 2 at least at three points of the central portion and the vicinity of both ends of the polishing-less elastic layer 3 with respect to the average outer diameter (r _av ) of the polishing-less elastic layer 3 The difference (L ₂ −L ₁ ) between the longest distance L ₂ to the outer peripheral surface and the shortest distance L ₁ is a value expressed as a percentage. More specifically, at each measurement point, the equation [(L ₂ -L _{1) / r av]} is calculated by × 100 (%). Here, the wobbling of the polishing-less elastic layer 3 is caused by the thickness of the polishing-less elastic layer 3 at each measurement point by a laser length measuring machine while rotating the conductive roller 1A around the central axis of the shaft body 2. Alternatively, the distance from the center point of the shaft body 2 to the outer peripheral surface of the polishing-less elastic layer 3 is measured, and from the measured maximum thickness and minimum thickness, or from the measured longest distance and shortest distance, the above formula Can be calculated.

  Thus, the polishing-less elastic layer 3 has a high outer diameter accuracy and a small runout. Therefore, the polishing-less elastic layer 3 has a high outer diameter accuracy, thereby having a uniform desired outer diameter in the longitudinal direction of the polishing-less elastic layer 3 and having a small runout. Since the polishing-less elastic layer 3 has a uniform desired thickness in the circumferential direction, for example, when it is provided in the image forming apparatus shown in FIG. Uniformly abuts against a contacted body such as an image bearing member over the longitudinal direction of the layer 3, and as a result, the conductive roller 1 </ b> A can uniformly act on the contacted body over the longitudinal direction. . Therefore, it is possible to sufficiently contribute to forming a high quality image.

  In addition to the outer diameter accuracy and the deflection, the polishing-less elastic layer 3 preferably has a surface roughness Rz of 2 to 15 μm. When the surface roughness Rz of the polishing-less elastic layer 3 is 2 to 15 μm, it is possible to efficiently charge and convey a developer having an average powder diameter (diameter) of 5 to 6 μm. The surface roughness Rz of the polishing-less elastic layer 3 is in accordance with JIS B 0601-1984 (10-point average roughness), and a surface roughness meter (trade name: 590A, Tokyo Seimitsu Co., Ltd.) equipped with a measuring probe having a tip radius of 2 μm. The conductive roller 1A provided with the polishing-less elastic layer 3 is set, and the surface roughness is measured at least at three points using a measurement length of 2.4 mm, a cutoff wavelength of 0.8 mm, and a cutoff type Gaussian. Is the surface roughness Rz.

  If the polishing-less elastic layer 3 has the outer diameter accuracy, the deflection, preferably the surface roughness Rz, the properties such as hardness, electrical resistance value and strength, and the material, thickness, etc. Not limited.

  In the present invention, the polishing-less elastic layer 3 preferably has a JIS A hardness of 10 to 90. When the polishing-less elastic layer 3 has a JIS A hardness of 10 to 90, the nip width between the conductive roller 1A and the abutting member such as the blade of the developer regulating member and the image bearing member is efficient. Therefore, it is easy to efficiently charge and convey the developer and improve the development efficiency. The JIS A hardness can be measured according to JIS K6253.

Further, the polishing-less elastic layer 3 preferably has an electric resistance value of 10 ² to 10 ⁹ Ω when used as a developing roller or the like in the image forming apparatus shown in FIG. When a conductive roller used as a roller of an image forming apparatus or the like has an electric resistance value of 10 ² to 10 ⁹ Ω, a desired charge can be reliably charged on the contacted body. For example, if the conductive roller 1A used as the developing roller has an electric resistance value of 10 ² to 10 ⁹ Ω, the developer can be reliably supported, and the supported developer can be image-supported. It can be reliably attached to the body as desired.

  The electric resistance value of the polishing-less elastic layer 3 can be set within the above range by adjusting the content of the conductivity imparting agent contained in the polishing-less elastic layer 3. (Product name: ULTRA HIGH RESISTANCE METER R8340A, manufactured by Advantest Co., Ltd.), the conductive roller 1A is placed horizontally, the thickness of 5 mm, the width of 30 mm, and the entire elastic layer 3 of the conductive roller 1A are placed. With the gold-plated plate having a length that can be used as an electrode, a load of 500 g is supported on both ends of the shaft body 2 in the conductive roller 1A, and DC 100 V is applied between the shaft body 2 and the electrode, It can be measured by reading the value of the electric resistance meter after 1 second and using this value as the electric resistance value.

  The rubber constituting the liquid conductive rubber composition forming the polishing-less elastic layer 3 may be a liquid rubber, and includes, for example, silicone or silicone-modified rubber, nitrile rubber, ethylene propylene rubber (ethylene propylene diene rubber). ), Styrene butadiene rubber, butadiene rubber, isoprene rubber, natural rubber, acrylic rubber, chloroprene rubber, butyl rubber, epichlorohydrin rubber, urethane rubber, fluorine rubber, and the like. These rubbers are preferably an addition-curing type because they are excellent in dimensional accuracy during heat molding.

  As for the electroconductivity imparting agent which comprises the said liquid conductive rubber composition, electroconductive powder, an ion electroconductive substance, etc. are mentioned, for example. More specifically, examples of the conductive powder include carbons for rubber such as SAF, ISAF, HAF, FEF, GPF, SRF, FT, and MT in addition to conductive carbon such as ketjen black and acetylene black. In addition, metals such as titanium oxide, zinc oxide, nickel, copper, silver, germanium, or conductive polymers such as metal oxide, polyaniline, polypyrrole, polyacetylene, etc. can be mentioned. Examples include inorganic ionic conductive materials such as sodium perchlorate, lithium perchlorate, calcium perchlorate, and lithium chloride. The conductivity-imparting agent is added in an appropriate content so as to exhibit a desired electric resistance value alone or in combination of two or more.

  The liquid conductive rubber composition may contain various additives usually contained in the rubber composition in addition to the rubber and the conductivity imparting agent. Examples of the various additives include a vulcanizing agent, Vulcanization accelerator, Vulcanization accelerator, Vulcanization retarder, Dispersant, Foaming agent, Anti-aging agent, Antioxidant, Filler, Pigment, Colorant, Processing aid, Softener, Plasticizer, Emulsifier, Examples thereof include a curing agent, a heat resistance improver, a flame retardant improver, an acid acceptor, a thermal conductivity improver, a release agent, and a solvent. These various additives may be commonly used additives or may be specially used additives depending on applications.

The liquid conductive rubber composition is particularly preferably an addition-curing liquid conductive silicone rubber composition because it can easily and reliably achieve high outer diameter accuracy and small runout during heat molding. The liquid conductive rubber composition includes, for example, (A) an organopolysiloxane containing at least two alkenyl groups bonded to a silicon atom in one molecule, and (B) a hydrogen atom bonded to a silicon atom in one molecule. An organohydrogenpolysiloxane containing at least two, (C) an inorganic filler having an average particle diameter of 1 to 30 μm and a bulk density of 0.1 to 0.5 g / cm ³ , and (D) imparting conductivity. Addition curing type liquid conductive silicone rubber composition containing an agent and (E) addition reaction catalyst.

As the (A) organopolysiloxane, a compound represented by an average composition formula (1) R ¹ _a SiO _{(4-a) / 2} is preferable. Here, R ¹ is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, preferably 1 to 8 carbon atoms, the same or different from each other, and a is 1.5 to 2.8, The positive number is preferably 1.8 to 2.5, more preferably 1.95 to 2.02.

R ¹ is, for example, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, cyclohexyl group, octyl group, nonyl group, decyl group. Alkyl groups such as cyclohexyl groups, cycloalkyl groups such as cyclohexyl groups, aryl groups such as phenyl groups, tolyl groups, xylyl groups, naphthyl groups, aralkyl groups such as benzyl groups, phenylethyl groups, β-phenylpropyl groups, vinyl groups, allyl groups Group, propenyl group, isopropenyl group, butenyl group, hexenyl group, cyclohexenyl group, octenyl group and other alkenyl groups, and part or all of the hydrogen atoms bonded to carbon atoms of these groups are halogen atoms or cyano groups Chloromethyl group, chloropropyl group, bromoethyl group, trif Oropuropiru group and a cyanoethyl group and the like.

At least two of R ¹ are preferably alkenyl groups having 2 to 8 carbon atoms, preferably 2 to 6 carbon atoms, particularly vinyl groups, and 90% or more of them are methyl groups. Is preferred. The content of the alkenyl group is 1.0 × 10 ^{−6 to} 5.0 × 10 ⁻³ mol / g, particularly 5.0 × 10 ^{−6 to} 1.0 × 10 ⁻³ mol / g in the organopolysiloxane. It is preferable that When the amount of the alkenyl group is less than 1.0 × 10 ⁻⁶ mol / g, the crosslinking may be insufficient and the gel may be formed. On the other hand, when the amount exceeds 5.0 × 10 ⁻³ mol / g, the compression permanent Not only may the strain decrease, but the rubber after crosslinking may become brittle. The alkenyl group may be bonded to the silicon atom at the end of the molecular chain, may be bonded to the silicon atom in the molecular chain, or may be bonded to both silicon atoms.

  The organopolysiloxane (A) basically has a linear structure having both ends of a molecular chain in which a triorganosiloxy group is bonded to a main chain having a diorganosiloxane unit as a repeating unit. It may be a branched structure or a ring structure.

  The degree of polymerization of the organopolysiloxane (A) is liquid at room temperature (25 ° C.) (for example, the viscosity at 25 ° C. is 100 to 1,000,000 mPa · s, preferably about 200 to 100,000 mPa · s). The average degree of polymerization is preferably 100 to 800, and particularly preferably 150 to 600. If the average degree of polymerization is less than 100, the rubber elasticity after crosslinking may be insufficient. On the other hand, if it exceeds 800, the organopolysiloxane (A) becomes a raw rubber and the compression set decreases. There is.

The (B) organohydrogenpolysiloxane is represented by an average composition formula (2) R ² _b H _c SiO _{(4-bc) / 2} , and is at least 2, preferably 3 or more per molecule ( Usually 3 to 200), more preferably 3 to 100 hydrogen atoms bonded to silicon atoms. This organohydrogenpolysiloxane is a curing agent (crosslinker) in which hydrogen atoms bonded to silicon atoms existing in the molecule undergo a hydrosilyl addition reaction with the alkenyl groups bonded to silicon atoms of the organopolysiloxane (A). Agent).

In the average composition formula (2), R ² is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms. B is 0.7 to 2.1, c is 0.001 to 1.0, and b + c is a positive number satisfying 0.8 to 3.0. R ² is the same as R ¹ , but preferably does not have an aliphatic unsaturated group. Further, b is preferably a positive number satisfying 0.8 to 2.0, c preferably 0.01 to 1.0, and b + c preferably 1.0 to 2.5. Siloxane may have a linear, cyclic, branched or three-dimensional network structure. The (B) organohydrogenpolysiloxane preferably has a liquid state at room temperature (25 ° C.) in which the number (or degree of polymerization) of silicon atoms in one molecule is 2 to 300, particularly about 4 to 150. In addition, the silicon atom to which the hydrogen atom is bonded may be at either the molecular chain end or the molecular chain, or may be at both.

  The content of hydrogen atoms (Si—H) bonded to the silicon atoms is preferably 0.001 to 0.017 mol / g, particularly 0.002 to 0.015 mol / g in the organohydrogenpolysiloxane. If the hydrogen atom content is less than 0.001 mol / g, crosslinking may be insufficient and gel may be formed. On the other hand, if it exceeds 0.017 mol / g, the crosslinking density becomes too high, Later rubber may become brittle.

Examples of the (B) organohydrogenpolysiloxane include a trimethylsiloxy group-capped methylhydrogen polysiloxane at both ends, a trimethylsiloxy group-capped dimethylsiloxane / methylhydrogensiloxane copolymer, and dimethylhydrogensiloxy groups at both ends. Blocked dimethylpolysiloxane, both ends dimethylhydrogensiloxy group blocked dimethylsiloxane / methylhydrogensiloxane copolymer, both ends trimethylsiloxy group blocked methylhydrogensiloxane / diphenylsiloxane copolymer, both ends trimethylsiloxy group blocked methylhydrogen diphenylsiloxane-dimethylsiloxane _copolymers, copolymers consisting of _(CH 3) 2 _{HSiO 1/2} units and _{SiO 4/2} units,及Include copolymers consisting of _{(CH 3)} 2 _{HSiO 1/2} units and _{SiO 4/2} units and _{(C 6} H _{5) SiO 3/2} units.

  The blending amount of (B) organohydrogenpolysiloxane is preferably 0.1 to 30 parts by weight, particularly 0.3 to 20 parts by weight, based on 100 parts by weight of (A) organopolysiloxane. preferable. If the blending amount is less than 0.1 parts by mass, the crosslinking may be insufficient and become a gel, and a rubber-like cured product may not be obtained. On the other hand, if it exceeds 30 parts by mass, Strength and compression set resistance may be significantly reduced. The molar ratio of the hydrogen atom bonded to the silicon atom with respect to the alkenyl group of (A) organopolysiloxane is preferably 0.3 to 5.0, particularly preferably 0.5 to 2.5. .

The (C) inorganic filler is an important component for obtaining low roller permanent set, volume resistivity stable over time, and sufficient roller durability. The inorganic filler has an average particle size of 1 to 30 μm, preferably 2 to 20 μm, and a bulk density of 0.1 to 0.5 g / cm ³ , preferably 0.15 to 0.45 g / cm ³ . If the average particle size is less than 1 μm, the electrical resistance may change over time, whereas if it is greater than 30 μm, the durability of the elastic layer 3 may be reduced. On the other hand, if the bulk density is less than 0.1 g / cm ³ , the compression set may deteriorate and the electrical resistivity may change over time. On the other hand, if it exceeds 0.5 μm, the strength of the elastic layer 3 is insufficient. Durability may decrease. The average particle diameter can be determined as a weight average value (or median diameter), for example, using a particle size distribution measuring device such as a laser diffraction method, and the bulk density is a measurement of the apparent specific gravity according to JIS K 6223. It can be determined based on the method.

  Examples of such inorganic fillers include diatomaceous earth, pearlite, mica, calcium carbonate, glass flakes, and hollow fillers, among which diatomaceous earth, pearlite, and foamed pearlite are preferable.

  The compounding amount of the inorganic filler is preferably 5 to 100 parts by mass, and particularly preferably 10 to 80 parts by mass with respect to 100 parts by mass of (A) organopolysiloxane. When the blending amount is less than 5 parts by mass, sufficient roller durability may not be exhibited. On the other hand, when it exceeds 100 parts by mass, the compression set decreases and it is difficult to blend uniformly. Sometimes.

  The inorganic filler (C) is a silane coupling agent or a partial hydrolyzate thereof, an alkylalkoxysilane or a partial hydrolyzate thereof, an organic silazane, a titanate coupling agent, an organopolysiloxane oil, a hydrolyzable Surface treatment may be performed with a functional group-containing organopolysiloxane or the like. These surface treatments may be performed in advance on the inorganic filler itself, or may be performed at the time of mixing the oil and the inorganic filler.

  The mixing method of the inorganic filler (C) may be mixed with the (A) organopolysiloxane and the (B) organohydrogenpolysiloxane using equipment such as a planetary mixer or a kneader at room temperature, Or you may mix at the high temperature of 100-200 degreeC.

  In addition to the inorganic filler (C), for example, inorganic powders such as quartz powder, spherical silica, fumed silica, precipitated silica, titanium oxide, alumina, aluminum hydroxide, etc. are used for low compression set, aging. And may be added in a range that does not impair stable volume resistivity and roller durability. In particular, fumed silica and precipitated silica, which have a great influence on the time-dependent change in compression set and volume resistivity, are 8 parts by mass or less, particularly 0 to 5 parts by mass with respect to 100 parts by mass of (A) organopolysiloxane. It is preferable to mix.

  The (D) conductivity-imparting agent is as already described. The blending amount of the (D) conductivity imparting agent is 10 kΩ · m or less, preferably 0.1 to 10 kΩ · m, particularly preferably 1 Ω · m to the cured product of the addition curable liquid conductive silicone rubber composition. An amount having a volume resistivity of 5 kΩ · m or less. Specifically, the blending amount of the conductivity imparting agent is preferably 0.5 to 50 parts by mass, particularly 1 to 20 parts by mass with respect to 100 parts by mass of the (A) organopolysiloxane. Is preferred. If the blending amount is less than 0.5 parts by mass, desired conductivity may not be obtained. On the other hand, if it exceeds 50 parts by mass, compression set may be reduced.

  Examples of the (E) addition reaction catalyst include platinum black, platinous chloride, chloroplatinic acid, a reaction product of chloroplatinic acid and a monohydric alcohol, a complex of chloroplatinic acid and an olefin, platinum bisacetoacetate, palladium And a rhodium-based catalyst. The addition amount of the addition reaction catalyst can be a catalytic amount. For example, the platinum group metal is 0% relative to the total mass of the (A) organopolysiloxane and the (B) organohydrogenpolysiloxane. 0.5 to 1,000 ppm is preferable, and about 1 to 500 ppm is particularly preferable.

  This addition curable liquid conductive silicone rubber composition is a low molecular siloxane ester, a silanol, for example, a dispersant such as diphenylsilanediol, an improved heat resistance such as iron oxide, cerium oxide, iron octylate, etc. Agents, various carbon functional silanes that improve adhesion and moldability, halogen compounds that impart flame retardancy, various reaction control agents, and the like may be included within a range that does not impair the object of the present invention.

  The liquid conductive rubber composition and the addition curable liquid conductive silicone rubber composition are prepared by using a rubber kneader such as a two-roller, three-roller, roller mill, Banbury mixer, and dough mixer (kneader). In addition, it is obtained by kneading, for example, several minutes to several hours, preferably 5 minutes to 1 hour at room temperature or under heating until the conductivity-imparting agent and various additives added as desired are uniformly mixed.

  The liquid conductive rubber composition and the addition curable liquid conductive silicone rubber composition can be easily and uniformly injected into a mold used in the method for manufacturing a conductive roller according to the present invention described later. In this respect, for example, at 25 ° C., the viscosity should be 5 to 500 Pa · s, and particularly preferably 10 to 200 Pa · s. The viscosities of the liquid conductive rubber composition and the addition curable liquid conductive silicone rubber composition can usually be adjusted by the type and / or blending amount of each component contained therein. If necessary, the viscosity can be adjusted with a solvent or the like.

  As shown in FIG. 2, the conductive roller according to the present invention may include a coat layer 4 on the outer peripheral surface of the polishing-less elastic layer 3. Providing the coat layer 4 on the outer peripheral surface of the polishingless elastic layer 3 has an effect that the developer can be charged and conveyed more efficiently due to its charging characteristics and the like. The material for forming the coating layer 4 is not particularly limited, but when the conductive roller 1B is used in the image forming apparatus shown in FIG. It is preferably a material that is hard to be permanently deformed due to contact or pressure contact. For example, alkyd resin, phenol-modified silicone modified alkyd resin, oil-free alkyd resin, acrylic resin, silicone resin, epoxy resin, Fluorine resin, phenol resin, polyamide resin, urethane resin, polyamideimide resin, and mixtures thereof can be used. The coat layer 4 is formed to a thickness of 1 to 100 μm, for example.

  The conductive rollers 1A and 1B according to the present invention (hereinafter sometimes referred to as the conductive roller 1) are obtained by heat-molding a liquid conductive rubber composition on the outer peripheral surface of the shaft body 2 using a mold. Manufactured. If the polishing-less elastic layer 3 of the conductive roller 1 is formed by such a liquid injection molding method, the molding conditions, the molding method, and the like are not particularly limited. Moreover, although the metal mold | die to be used is not specifically limited, It is good that the surface roughness of the inner surface is adjusted, and it is especially good that it is set as the mirror surface. The surface roughness of the inner surface of the mold can be adjusted by, for example, polishing treatment, grinding treatment and / or cutting treatment. In order to make the inner surface into a mirror surface, the inner surface is made into a mirror surface according to a standard method. A process such as a honing process or a polishing process can be employed. For example, the conductive roller 1 injects the liquid conductive rubber composition into a cavity formed by a mold and the shaft body held by the mold at a temperature of 60 ° C. or lower, for example, room temperature, It can manufacture by heating to predetermined temperature.

  The following manufacturing method is mentioned as a manufacturing method which can manufacture the electroconductive roller 1 provided with the abrasion-less elastic layer 3 which has the said outer diameter precision and the said shake more easily.

That is, (1) a vulcanization characteristic calculation step for calculating a vulcanization characteristic X corresponding to the desired outer diameter of the polishing-less elastic layer from the following formula:
Y = aX + b (where, a is −0.0046 to −0.0026, b is 20.07 to 20.14, Y is the outer diameter (unit: mm) of the polishing-less elastic layer, and X is Sulfur characteristic tc (10) (unit: second) is shown.)
(2) a composition preparation step for preparing a liquid conductive rubber composition having a vulcanization characteristic with a calculated X value ± 10;
(3) The liquid conductive rubber composition is injected into a cavity formed by a mold and the shaft body held by the mold, and includes a molding step for heat molding (hereinafter, referred to as a manufacturing method). It may be referred to as a manufacturing method according to the present invention).

  In this manufacturing method, first, from the above formula, the liquid conductivity capable of forming a polishing-less elastic layer corresponding to the outer diameter Y so as to adjust the outer diameter of the polishing-less elastic layer to a desired outer diameter Y. A vulcanization characteristic X required for the rubber composition is calculated.

  The above formula shows that the outer diameter of the molded polishing-less elastic layer varies depending on the curability of the liquid conductive rubber composition, that is, the vulcanization characteristic tc (10), and the vulcanization characteristic tc (10) and the polishing-less elasticity. This is the first expression found by the present applicant that the outer diameter of the layer has a certain relationship, and represents the relationship between the vulcanization characteristic tc (10) and the outer diameter of the polishing-less elastic layer. Therefore, if the vulcanization characteristic X of the liquid conductive rubber composition is calculated from the desired outer diameter Y based on the formula Y = aX + b, a polishing-less elastic layer having the desired outer diameter can be formed. .

  In the formula Y = aX + b, a is −0.0046 to −0.0026, preferably −0.0044 to −0.0028, particularly preferably −0.0038. Moreover, in the said formula, b is 20.07-20.14, It is preferable that it is 20.0.085-20.13, It is especially preferable that it is 20.11. As shown in FIG. 3, the region satisfying the formula Y = aX + b is equal to or smaller than the region represented by Y = −0.0026X + 20.14 and greater than or equal to the region represented by Y = −0.0046X + 20.07. It is an area.

  The vulcanization characteristic tc (10) of the liquid conductive rubber composition is that the liquid conductive rubber composition is gradually crosslinked with respect to the rotational torque T100 when the liquid conductive rubber composition is almost completely crosslinked. This is a characteristic expressed as time when the rotational torque of the liquid conductive rubber composition in the middle of crosslinking reaches a rotational torque value of 10%. This vulcanization characteristic tc (10) is obtained by using, for example, a measuring instrument capable of measuring the rotational torque of a liquid sample such as a rheometer, using JIS K6300-2 (unvulcanized rubber vibration vulcanization tester). It can be measured according to the measuring method described in (How to obtain).

  In the present invention, the vulcanization characteristic of the liquid conductive rubber composition is based on tc (10). However, the liquefaction characteristic in which the vulcanization characteristic tc (10) and the outer diameter Y satisfy the above equation. Vulcanization characteristics tc other than tc (10), for example, tc (50) representing the time when the rotational torque reaches a rotational torque value of 50% of the rotational torque T100, Using tc (90) representing the time when the torque becomes 90% of the rotational torque value with respect to the rotational torque T100, a relational expression between these vulcanization characteristics tc and the outer diameter Y is created and added. The sulfur characteristic tc may be calculated.

  In the manufacturing method according to the present invention, a liquid conductive rubber composition having a vulcanization characteristic of X value ± 10 (seconds) calculated in the vulcanization characteristic calculation step is then prepared. If the vulcanization characteristic of the liquid conductive rubber composition is the value of X ± 10 (seconds), a polishing-less elastic layer having a desired outer diameter can be formed. The vulcanization characteristic of the liquid conductive rubber composition is preferably the value of X ± 5 (seconds) in that a polishing-less elastic layer having a desired outer diameter can be easily formed. It is more preferable that the value is ± 2 (seconds). The liquid conductive rubber composition is as described above, and in order to adjust the vulcanization characteristics of the liquid conductive rubber composition as desired, for example, the type and / or content of each component such as rubber May be adjusted as appropriate. More specifically, for example, when the liquid conductive rubber composition is the addition-curable liquid conductive silicone rubber composition, the type and / or amount of the organopolysiloxane, the organohydrogenpolysiloxane The type and / or blending amount of the catalyst, the type and / or blending amount of the addition reaction catalyst, the type and / or blending amount of the reaction control agent optionally added, and the like may be adjusted as appropriate. For example, the blending amount of the organohydrogenpolysiloxane is determined based on the calibration curve by creating a calibration curve representing the relationship between the blending amount of the organohydrogenpolysiloxane and the vulcanization characteristic tc (10). May be.

  In the manufacturing method according to the present invention, the primer coating step can be performed on the shaft body manufactured according to a conventional method before performing the molding step described later. The primer applied to the shaft body is not particularly limited. For example, alkyd resin, modified alkyd resin such as phenol modified / silicone modified, oil-free alkyd resin, acrylic resin, silicone resin, epoxy resin, fluororesin, phenol Examples thereof include resins, polyamide resins, urethane resins, and mixtures thereof. Among these, a primer having an amino group and / or a hydroxyl group is preferable. Moreover, as a crosslinking agent which hardens and / or vulcanizes these resin, an isocyanate compound, a melamine compound, an epoxy compound, a peroxide, a phenol compound, a hydrogen siloxane compound etc. are mentioned, for example. The primer is dissolved in a solvent or the like as desired, and is applied to the outer peripheral surface of the shaft body according to a conventional method such as a dipping method or a spray method.

  In the manufacturing method according to the present invention, the liquid conductive rubber composition prepared in the composition preparation step is then injected into a cavity formed by a mold and the shaft body held by the mold. Then, heat mold. As a method for injecting the liquid conductive rubber composition into the cavity, any method can be adopted as long as it is a regular method. Examples thereof include injection by an injection molding machine and injection by a casting machine.

  The conditions for thermoforming the liquid conductive rubber composition injected into the cavity may be any conditions that allow the liquid conductive rubber composition to be vulcanized. For example, the heating temperature may be set to 100 to 300 ° C. The heating time can be set from 10 seconds to 1 hour.

  The mold used in this molding process may be a mold capable of holding the shaft body 2, preferably a cylindrical mold. Further, this mold is preferably adjusted to have a surface roughness on its inner surface, and is particularly preferably a mirror surface. As a preferable mold used in the molding step, for example, as shown in FIG. 4, a cylindrical hollow body 11, a lower end piece 12, and an upper end piece 13 are provided. The lower end piece 12 is opened, the holding hole 15 for holding the shaft body 2 and the liquid conductive rubber composition can be injected, and the diameter of the cross section increases toward the cavity 14 formed when the mold is assembled. At least one sprue 16 that closes the lower end opening of the cylindrical hollow body 11, and the upper end piece 13 has a holding hole 17 for holding the shaft body 2, as shown clearly in FIG. At least one vent 18 whose cross section expands toward the cavity 14 formed when the mold is assembled, and a liquid formed in communication with the vent 18 above the vent 18. With a reservoir 19 and in a cylindrical shape Mold 10 which closes the top opening of the body 11 and the like.

  Regardless of the viscosity of the liquid conductive rubber composition, the opening diameter of the opening 18d of the vent 18 (that is, the minimum diameter of the vent 18) in the liquid reservoir 19 formed in the upper end piece 13 constituting the mold 10 is as follows. It is preferably 1 to 10 mm, particularly preferably 2 to 5 mm, from the viewpoint that a high-precision polishing-less elastic layer having high outer diameter accuracy and small runout can be easily formed.

  An example of the molding process in the manufacturing method according to the present invention will be described using a mold 10. First, as shown in FIG. 4, the lower end piece 12 is arranged on the lower side of the cylindrical hollow body 11, the upper end piece 13 is arranged on the upper side, and the shaft body 2 is passed through the cylindrical hollow body 11. The mold 10 is assembled such that both ends are held between the holding hole 15 of the lower end piece 12 and the holding hole 17 of the upper end piece 13, and then the liquid conductive material having desired vulcanization characteristics from the sprue 16 of the lower end piece 12. The conductive rubber composition is injected into the cavity 14 formed by the mold 10 and the shaft body 2 held by the mold 10 by a conventional method, and the liquid conductive rubber composition is injected under the thermoforming conditions. Heat molding.

  In the production method according to the present invention, for the purpose of reducing the compression set, or for the purpose of reducing the low molecular siloxane component in the addition-curable liquid conductive silicone rubber composition, after the molding step, Secondary vulcanization can be performed at a heating temperature of 120 to 250 ° C. for about 30 minutes to 70 hours.

  The abrasive-less elastic layer formed in this way is flat and can satisfy high outer diameter accuracy and small runout.

  In the manufacturing method according to the present invention, the coat layer 4 is formed on the outer peripheral surface of the polishing-less elastic layer 3 formed by the molding step as desired. The coating layer 4 dissolves the material in a solvent or the like as desired, and is applied to the outer peripheral surface of the polishing-less elastic layer 3 according to a conventional method, for example, a dip method, a spray method, etc. Formed.

  According to the production method of the present invention, the liquid conductive rubber composition having a specific range of vulcanization characteristics calculated from the above formula is used as the liquid conductive rubber composition forming the polishing-less elastic layer, and Since the conductive roller 1 is manufactured using a mold, in the liquid injection molding method, the pressure in the mold 10, the dimensional accuracy of the mold 10, the heating temperature during thermoforming, the injection of the liquid conductive rubber composition The conductive roller 1 having a high-precision elastic layer that is flat and satisfies a high outer diameter accuracy and a small run-out without accurately adjusting the method, the cure shrinkage rate, etc. of the liquid conductive rubber composition. Can be manufactured easily. Therefore, according to the manufacturing method according to the present invention, it is necessary to adjust the outer diameter of the polishing-less elastic layer formed in this manner by performing outer diameter adjustment processing such as polishing, grinding, and cutting. Not particularly.

  In the present invention, as described above, by adjusting the vulcanization characteristic tc (10) of the liquid conductive rubber composition forming the conductive roller, the polishing-less elastic layer having the outer diameter accuracy and the runout is obtained. The conductive roller provided with a polishing-less elastic layer having a desired outer diameter that is the same as or smaller than the inner diameter of a mold used, particularly a cylindrical hollow body, can be manufactured more easily. Can also be manufactured.

  That is, another manufacturing method of a conductive roller (hereinafter referred to as another manufacturing method according to the present invention) capable of manufacturing a conductive roller having a polishingless elastic layer having a desired outer diameter according to the present invention. Is a method of manufacturing a conductive roller that includes a shaft body and a polishing-less elastic layer formed on the outer peripheral surface thereof, and is disposed in the image forming apparatus, and has a predetermined inner diameter. A liquid conductive rubber composition having a vulcanization characteristic tc (10) of 25 to 45 is injected into a cavity formed by a mold and the shaft body held by the mold, and heated, and the mold is heated. A method for producing a conductive roller, characterized in that a polishing-less elastic layer having an outer diameter equal to or smaller than the inner diameter is formed.

  In another manufacturing method according to the present invention, the liquid conductive rubber composition injected into the cavity has the vulcanization characteristic tc (10) of 25 to 45 as described above. This is the same as the manufacturing method.

  Another manufacturing method according to the present invention is that the outer diameter of the molded polishing-less elastic layer changes, and that the vulcanization characteristic tc (10) and the outer diameter of the polishing-less elastic layer have a certain relationship. As a result of the first finding by the applicant, it is possible to form a polishing-less elastic layer having the desired outer diameter that is the same as or smaller than the inner diameter of the mold by adjusting the vulcanization characteristic tc (10). . That is, according to the vulcanization characteristic tc (10) of the liquid conductive rubber composition, as is clear from the above formula Y = aX + b representing the relationship between the vulcanization characteristic tc (10) and the outer diameter of the polishing-less elastic layer. Since the outer diameter Y of the formed polishing-less elastic layer changes, by adjusting the vulcanization characteristic tc (10) of the liquid conductive rubber composition, a mold having the same inner diameter, particularly the same inner diameter. Even when the cylindrical hollow body 11 is used, it is possible to produce a polishing-less elastic layer having a different outer diameter equal to or less than the inner diameter of the mold, particularly the cylindrical hollow body 11. Even if the vulcanization characteristic tc (10) is less than 25 or more than 45, a polishing-less elastic layer having a desired outer diameter cannot be easily produced.

  For example, in another manufacturing method according to the present invention, when a cylindrical hollow body 11 having an appropriate inner diameter is used, a liquid conductive rubber composition having a vulcanization characteristic tc (10) of 27 (seconds) The conductive roller manufactured by using a liquid conductive rubber composition having an outer diameter of about 20.007 mm and a vulcanization characteristic tc (10) of 42 (seconds) is about Two conductive rollers having an outer diameter of 19.950 mm and an outer diameter difference of about 0.06 mm can be manufactured.

  In another manufacturing method according to the present invention, since the inner diameter of the cylindrical hollow body 11 can be set to various values, the outer diameter of the conductive roller is not limited to about 20 mm described in the above example. Of course.

  Thus, according to another manufacturing method according to the present invention, the polishing is performed by thermoforming the liquid conductive rubber composition by adjusting the vulcanization characteristic tc (10) of the liquid conductive rubber composition. The outer diameter of the loess elastic layer can be adjusted as desired.

  Moreover, according to another manufacturing method according to the present invention, since the vulcanization characteristic tc (10) of the liquid conductive rubber composition is adjusted, naturally, as in the above-described manufacturing method according to the present invention, It is also possible to more easily form a high-precision polishing-less elastic layer having high outer diameter accuracy and small runout.

  Next, an image forming apparatus including the conductive roller according to the present invention, or the conductive roller manufactured by the manufacturing method according to the present invention or another manufacturing method according to the present invention (hereinafter referred to as image forming according to the present invention). An example will be described with reference to FIG.

  As shown in FIG. 6, the image forming apparatus 30 according to the present invention includes a rotatable image carrier 31 on which an electrostatic latent image is formed, for example, a photosensitive member, and abuts or presses against the image carrier 31 or A charging unit 32 that charges the image carrier 31, for example, a charging roller, and an exposure unit 33 that is provided above the image carrier 31 and forms an electrostatic latent image on the image carrier 31. A developing means 40 which is provided in contact with or pressure contact with the image carrier 31 or at a predetermined interval, supplies the developer 42 with a constant layer thickness to the image carrier 31 and develops the electrostatic latent image; The transfer means 34 is provided so as to be pressed against the image carrier 31 and transfers the developed electrostatic latent image from the image carrier 31 onto the transfer paper 36, for example, a transfer roller, and the transfer paper 36 in the transport direction. Developer 42 (provided downstream and transferred to transfer paper 36) Fixing means 35 for fixing the electrostatic latent image), for example, a fixing device, and a cleaning means 37 for removing the developer 42 not transferred to the transfer paper 36 and remaining on the image carrier 31 and / or dust adhering to the image carrier 31. And. That is, the image carrier 31 is subjected to each action by the cleaning unit 37, the charging unit 32, the exposure unit 33, the developing unit 40, and the transfer unit 34 in order from the upstream side in the rotation direction.

  The image carrier 31 can be a conventionally known image carrier, and at least the photosensitive layer provided on the surface thereof is made of, for example, an organic material, amorphous silicon, a Se alloy, or a combination thereof. It is formed. When the image carrier 31 is cylindrical, the image carrier 31 can be manufactured by a known production method such as a method of forming a photosensitive layer or the like on the surface after extrusion molding of aluminum or an aluminum alloy. It is also possible to use a belt-like image carrier. The charging unit 32 only needs to be able to charge the image carrier 31. For example, a contact-type charger using a conductive or semiconductive roller, brush, film, rubber blade, or corona discharge is used. A charger such as a scorotron charger or a corotron charger can be used. Among these, a contact-type charger is preferable in terms of excellent charge compensation capability. The exposure means 33 only needs to be able to form an electrostatic latent image on the image carrier 31 by exposure. For example, a semiconductor laser (LD) light, a light emitting diode (LED) light, a liquid crystal is formed on the surface of the image carrier 31. Light sources such as shutter (LCS) light, or optical equipment that can be exposed in a desired image form from these light sources through a polygon mirror can be used. The transfer means 34 only needs to be able to transfer the developed electrostatic latent image from the image carrier 31 onto the transfer paper 36. For example, a contact-type transfer charger using a belt, a roller, a film, a rubber blade, or the like. A scorotron transfer charger using a corona discharge, a corotron transfer charger, or the like can be used. Among these, a contact type transfer charger is preferable in that it has excellent transfer charge compensation capability. In addition to the transfer charger, a peeling charger can be used in combination. The fixing means 35 only needs to fix the developer 42 (electrostatic latent image) transferred to the transfer paper 36. For example, a heat roller fixing device having a heat generating fixing roller, an oven fixing device, etc. A heat fixing device, a pressure fixing device including a pressurizing fixing roller, or the like can be used. As the cleaning means 37, it is sufficient that the developer 42 and / or dust on the image carrier 31 can be removed, and a known cleaning device, a cleaning roller, or the like can be used.

  The image forming apparatus 30 includes a neutralizing unit (not shown) for removing an electrostatic latent image remaining on the surface of the image carrier 31 between the cleaning unit 37 and the charging unit 32 or the transfer unit 34 and the cleaning unit. 37 may be provided. For example, a tungsten lamp, an LED, or the like can be used as the static elimination means. Examples of the light quality used for the optical static elimination means include white light such as a tungsten lamp, red light such as LED light, and the like. In general, the output is set so as to be about several to thirty times the amount of light indicating the half exposure sensitivity of the image carrier 31.

  The developing means 40 in the image forming apparatus 30 is basically formed in the same manner as the developing means provided in the conventional image forming apparatus, and is arranged in the same manner. For example, as shown in FIG. 6, the developing unit 40 has an opening at a position facing the image carrier 31, and includes a developer storage unit 41 that stores the developer 42, and a developer storage unit 41. An agitator 43 for uniformly agitating the developer 42, and an opening of the developer accommodating portion 41. The agitator 43 is in contact with or pressed against the image carrier 31 or at a predetermined interval. A rotatable developer carrier 44 for supplying the developer 42 with a constant layer thickness to the developer 31 and a developer carrier 44 provided above the developer carrier 44 and in contact with the developer carrier 44 are provided. And a developer regulating member 45 that charges the developer 42 by frictional charging.

  The developer 42 accommodated in the developer accommodating portion 41, that is, the developer 42 used in the image forming apparatus 30 according to the present invention, is a one-component system that can be charged by friction and can be fixed to the transfer paper 36. The developer may be a dry developer or a wet developer, and may be a non-magnetic developer or a magnetic developer. The one-component developer generally includes a resin, a colorant, and other additives, and the resin is selected according to the fixing method. In the case of the heat fixing method, as the resin, for example, a styrene / acrylic copolymer or a styrene / butadiene copolymer, and in the case of the pressure fixing method, for example, a wax or an ethylene / vinyl acetate copolymer. Styrene / butadiene rubber mixed waxy resin or the like is selected. Examples of the colorant include carbon black, magnetite, various dyes and pigments, and examples of other additives include a charge control agent, a conductivity control agent, a reinforcing agent, and a release agent. In the case of a magnetic developer, magnetic powder such as ferrite is further contained by several tens of mass% with respect to the total mass of the developer 42. One-component developers usually have a charging characteristic of about 2 to 8 μC / g.

  The developer carrier 44 in the developing unit 40 contacts the blade 46 of the developer regulating member 45 to charge the developer 42. Therefore, the developer carrier 44 only needs to be configured so as to be able to charge the developer 42 by contacting the blade 46 of the developer regulating member 45, and includes, for example, an elastic layer having conductivity. Developing roller and the like. For example, for example, the conductive roller 1 according to the present invention can be used as such a developer carrying member 44, particularly a developing roller.

  For example, as shown in FIG. 6, the developer regulating member 45 includes a support and a blade 46. The support is formed of an elastic material, such as stainless steel, supports the blade 46, and makes the blade 46 contact the developer carrier 44 with an appropriate pressure. The blade 46 is formed of an elastic material, such as stainless steel or a thin plate having elasticity, and is in contact with the developer carrier 44 to regulate the layer thickness of the developer 42 and by frictional charging. The developer 42 is charged. The blade 46 may have a surface layer (not shown) for charging the developer 42 on the surface thereof.

  The image forming apparatus 30 according to the present invention includes a charging roller of the charging unit 32, a developing roller of the developing unit 40, a transfer roller of the transfer unit 34, a fixing roller of the fixing unit 35, a cleaning roller (not shown) of the cleaning unit, and an addition. Various rollers such as a pressure roller (not shown) and a paper feed / conveyance roller (not shown) are provided, and the conductive roller 1 according to the present invention is used as at least one of these various rollers. Preferably, the conductive roller 1 according to the present invention is used as at least one of a charging roller, a developing roller, a transfer roller, and a fixing roller.

  The image forming apparatus 30 according to the present invention operates as follows. As described above, the image forming apparatus 30 has the configuration shown in FIG. The developer regulating member 45 is disposed in the opening of the developing unit 40 such that the blade 46 is curved so that the blade 46 contacts the surface of the developer carrier 44 with a predetermined pressure.

  In the image forming apparatus 30, first, the developer 42 and / or dust on the surface of the image carrier 31 is removed by the cleaning unit 37 while rotating clockwise as indicated by the arrow in FIG. 6. Thereafter, it is uniformly charged by the charging means 32. Next, the image is exposed by the exposure means 33, and an electrostatic latent image is formed on the surface of the image carrier 31.

  On the other hand, in the developing means 40, the developer 42 uniformly mixed by the stirrer 43 is supplied to the developer carrier 44, and the developer carrier 44 rotates in the direction of the arrow shown in FIG. The developer 42 attached to the surface of the carrier 44 passes between the developer carrier 44 and the blade 46 of the developer regulating member 45 in contact with the developer carrier 44. At this time, the developer 42 is regulated to a desired layer thickness, and the developer 42 can be charged as desired. That is, as the developer 42 passes between the developer carrier 44 and the blade 46 of the developer regulating member 45, the layer thickness of the developer 42 on the surface of the developer carrier 44 is regulated. The developer 42 on the developer carrier 44 is charged as desired by friction charging between the blade 46 of the developer regulating member 45 and the developer carrier 44 and / or the developer 42.

  Next, the developer 42 having a desired layer thickness and charge amount is supplied from the developing means 40 to the image carrier 31 in this way, and the electrostatic latent image formed on the image carrier 31 is developed. The electrostatic latent image is visualized as a developer image. In this way, the developing unit 40 can supply the developer 42 having a desired layer thickness and charge amount to the image carrier 31 to develop the electrostatic latent image. Next, the developer image developed on the image carrier 31 is transferred onto the transfer paper 36 conveyed between the image carrier 31 and the transfer unit 34 by a conveyance unit (not shown). Transfer is performed by the transfer means 34. Next, the transfer paper 36 onto which the developer image has been transferred is conveyed to a fixing unit 35 by a conveying unit (not shown), and heated and / or pressurized by the fixing unit 35, and the transferred developer image is transferred as a permanent image. It is fixed on the paper 36. In this way, an image can be formed on the transfer paper 36.

  The image forming apparatus 30 according to the present invention includes a charging roller, a developing roller, a transfer roller, a fixing roller, a cleaning roller (not shown), a pressure roller (not shown), a paper feed / conveying roller (not shown), and the like. Since the conductive roller 1 according to the present invention is used as at least one of the various rollers, the roller in which the conductive roller 1 according to the present invention is used is the longitudinal direction of the contacted body. And can contribute to the formation of a high-quality image. For example, when the conductive roller 1 according to the present invention is used as the developing roller 44 disposed so as to be in contact with the image carrier 31, the developing roller 44 is uniform over the longitudinal direction of the developing roller 44 with a predetermined pressure. Since the developer 42 is brought into contact with the blade 46 and the image carrier 31 and the developer 42 can be adhered to the image carrier 31 with a uniform thickness with high accuracy, it can sufficiently contribute to the formation of a high-quality image. it can. In FIG. 6, the image carrier 31 and the developer carrier 44 of the developing unit 40 are separated from each other in the image forming apparatus 30 so that the movement process of the developer 42 can be easily understood.

  In the image forming apparatus 30 according to the present invention, the image carrier 31, the charging unit 32, the exposure unit 33, the transfer unit 34, the fixing unit 35, and the cleaning unit 37 are arranged in addition to the arrangement shown in FIG. The image carrier, the charging unit, the exposure unit, the transfer unit, the fixing unit and the cleaning unit provided in the apparatus may be formed in the same manner and arranged in the same manner.

  The image forming apparatus 30 is an electrophotographic image forming apparatus. However, in the present invention, the image forming apparatus is not limited to the electrophotographic system, and is, for example, an electrostatic image forming apparatus. May be. Further, the image forming apparatus 30 is a monochrome image forming apparatus in which the developing unit 40 contains only a single color developer 42. However, in this invention, the image forming apparatus is not limited to a monochrome image forming apparatus. It may be an image forming apparatus. Examples of the color image forming apparatus include a four-cycle color image forming apparatus that sequentially repeats primary transfer of a developer image carried on an image carrier to an intermediate transfer body, and a plurality of image carriers provided with developing means for each color. Examples thereof include a tandem type color image forming apparatus in which a body is arranged in series on an intermediate transfer body or a transfer conveyance belt. The image forming apparatus 30 is an image forming apparatus such as a copying machine, a facsimile machine, or a printer.

  In the image forming apparatus 30, a one-component developer is advantageously used as the developer 42, but a two-component developer including a toner and a carrier such as iron or nickel can also be used. . The two-component developer usually has a charging characteristic of about 10 to 25 μC / g.

Example 1
First, the metal mold | die shown by FIG.4 and FIG.5 was produced. That is, the mold 10 including the hollow cavity 11, the lower end piece 12, and the upper end piece 13 shown in FIG. 4 and having a cavity 14 having a diameter (outer diameter) of 35 mm, an (inner diameter) of 20 mm, and a length of 240 mm was produced. Each of the lower end piece 12 and the upper end piece 13 has a thickness of 25 mm, and holding holes 15 and 17 having a diameter of 7.5 mm are formed in the inner center portion thereof. The lower end piece 12 is formed with a frustoconical sprue 16 having a central axis at a position 8.25 mm from the central axis. The sprue 16 has a diameter of 2.5 mm on the raw material inlet side and a cavity side. The diameter is 3.0 mm. As shown in FIG. 5, the upper end piece 13 is provided with a frustoconical vent 18 having a central axis at a position 8.25 mm from the central axis and a liquid reservoir 19 on the upper part thereof. The depth is 20 mm, the vent 18 is 5 mm long, the opening diameter on the liquid reservoir 19 side is 2.5 mm, and the opening diameter on the cavity side is 3.0 mm. Eight sprues 16 and eight vents 18 are equally arranged in the circumferential direction. The inner surface of the cylindrical hollow body 11 was polished according to a conventional method.

An addition curable liquid conductive silicone rubber composition was prepared as follows. That is, 100 parts by mass of dimethylpolysiloxane (A) (degree of polymerization 300) blocked at both ends with dimethylvinylsiloxy groups, and a hydrophobized fumed silica having a BET specific surface area of 110 m ² / g (Nippon Aerosil Co., Ltd.) Made by company, R-972) 1 part by mass, average particle size 6 μm, bulk density of 0.25 g / cm ³ diatomaceous earth (C) (Oplite W-3005S, manufactured by Hokuaki Diatomite Co., Ltd.) 40 parts by mass, and 5 parts by mass of acetylene black (D) (Denka Black HS-100, manufactured by Denki Kagaku Kogyo Co., Ltd.) was put into a planetary mixer, stirred for 30 minutes, and then passed once through three rolls. This is returned to the planetary mixer again, and methylhydrogenpolysiloxane (B) having Si—H groups at both ends and side chains as a crosslinking agent (polymerization degree 17, Si—H amount 0.0060 mol / g) 2. 1 part by mass, 0.1 part by mass of ethynylcyclohexanol as a reaction control agent and 0.1 part by mass of a platinum catalyst (E) (Pt concentration 1%) are added and stirred and kneaded for 15 minutes. The product was designated as a silicone rubber composition (1).

  The vulcanization characteristic tc (10) of this silicone rubber composition (1) is based on the method described in JIS K6300-2 using a rotational torque meter (trade name “ELASTOGRAP67.93”, manufactured by GOTTFERT Corporation). It was 33 when measured. The measurement conditions at this time were vulcanization set temperature: 150 ° C., torque: 100 kgf-cm, measurement time: 5 min, and deflection angle ± 3 °. In addition, the viscosity of the silicone rubber composition (1) at 25 ° C. was 82 Pa · s.

  On the other hand, an electroless nickel-plated shaft body (SUM22, diameter 7.5 mm, length 281.5 mm) was washed with toluene, and a silicone primer (trade name “Primer No. 16”, Shin-Etsu Chemical Co., Ltd.) was applied. The shaft body subjected to the primer treatment was fired at a temperature of 150 ° C. for 10 minutes using a gear oven, and then cooled at room temperature for 30 minutes or more to form a primer layer on the surface of the shaft body.

  Next, a mold made of a holding hole 15 of the lower end piece 12 and a holding hole 17 of the upper end piece 13 was applied to the mold 10 by a release agent (trade name “Die Free” manufactured by Daikin Industries, Ltd.). After being held in the center of the cavity 14, the mold 10 is assembled and the silicone rubber composition (1) is started until the silicone rubber composition (1) starts to flow from the sprue 16 of the lower end piece 12 through the vent 18 to the liquid reservoir 19. 1) was injected. Subsequently, it heated to 150 degreeC from the metal mold | die 10 exterior, and was hold | maintained for 10 minutes at the same temperature, and the silicone rubber composition (1) was heat-molded. After the heat molding, the mold 10 is allowed to cool and the molded product is taken out of the mold 10, and the sprue 16 and vent 18 portions where the rubber is adhered are cut and removed to provide a conductive material having a polishing-less elastic layer. The neutral roller 1a was produced.

The outer diameter of the polishing-less elastic layer of the conductive roller 1a was measured with a laser length measuring machine. The measurement positions were five points (circumference of the polishing-less elastic layer) obtained by equally dividing the length of 10 mm from each end of the polishing-less elastic layer into four equal parts. The average outer diameter (diameter, r _av ) of the five points is 19.985 mm, and the outer diameter difference between the outer diameter (r _x ) and the average outer diameter (r _av ) at each measurement point with respect to this average outer diameter (r The percentage of _x− r _av ) calculated by the above formula is in the range of +0.140 to −0.055%, and the outer diameter accuracy of the polishing-less elastic layer is in the range of ± 0.25%. Was in.

Similarly, while rotating around the central axis of the conductive roller 1a shaft body 2, the outer circumference of the polishing-less elastic layer from the center point 2C of the shaft body 2 at the five measurement positions is measured by the laser length measuring machine. The difference (L ₂ −L ₁ ) between the longest distance L ₂ to the surface and the shortest distance L ₁ was measured. Then, the difference in the measurement points the difference between the longest distance _{L 2} and the shortest distance _{L 1 (L} 2 -L ₁₎ is the largest _(L 2 -L ₁₎ is 0.072 mm, the average outer diameter (r The percentage of the difference (L ₂ −L ₁ ) relative to _av ) was calculated by the above formula and found to be 0.36%, and the run-out of this polishingless elastic layer was 0.5% or less. The minimum value of runout of the polishingless elastic layer was 0.05%.

Further, when the surface roughness Rz of the polishingless elastic layer in the conductive roller 1a was measured by the above method, it was 4.5 μm, and when the JIS A hardness of the polishingless elastic layer in the conductive roller 1a was measured by the above method 43 The electrical resistance value of the polishing-less elastic layer in the conductive roller 1a was measured by the above method and found to be 5.0 × 10 ⁶ Ω.

(Example 2)
Except for using the silicone rubber composition (2) in which the addition amount of the platinum catalyst contained in the silicone rubber composition (1) was adjusted more than the addition amount in Example 1, the same procedure as in Example 1 was performed. A conductive roller 1b was produced.

When the vulcanization characteristic tc (10) and viscosity of this silicone rubber composition (2) were measured in the same manner as in Example 1, the vulcanization characteristic tc (10) was 27 (seconds) and the viscosity was 82 Pa · s. Met. Further, the average outer diameter (diameter, r _av ) and outer diameter accuracy of the polishing-less elastic layer of the conductive roller 1b, and the maximum difference (L ₂ −L ₁ ) between the longest distance L ₂ and the shortest distance L _1. The value, minimum value, and runout at this time were measured in the same manner as in Example 1, and were found to be 20.007 mm, 0.095 to -0.035%, 0.088 mm and 0.022 mm, and 0, respectively. .44% and 0.11%. Further, when measured in the same manner as in Example 1, the surface roughness Rz of the polishing-less elastic layer in the conductive roller 1b is 4.5 μm, the JIS A hardness is 43, and the electric resistance value is 5.0 ×. 10 ⁶ Ω.

Example 3
Except for using the silicone rubber composition (3) in which the addition amount of the platinum catalyst contained in the silicone rubber composition (1) was adjusted to be less than the addition amount in Example 1, the same procedure as in Example 1 was performed. A conductive roller 1c was produced.

When the vulcanization characteristic tc (10) and viscosity of this silicone rubber composition (3) were measured in the same manner as in Example 1, the vulcanization characteristic tc (10) was 42 (seconds) and the viscosity was 82 Pa · s. Met. Further, the average outer diameter (diameter, r _av ) and outer diameter accuracy of the polishing-less elastic layer of the conductive roller 1c, and the maximum difference (L ₂ −L ₁ ) between the longest distance L ₂ and the shortest distance L _1. The value, the minimum value, and the shake at this time were measured in the same manner as in Example 1, and were found to be 19.950 mm, 0.055-0.045%, 0.042 mm and 0.033 mm, and 0, respectively. .21% and 0.17%. Further, when measured in the same manner as in Example 1, the surface roughness Rz of the polishing-less elastic layer in the conductive roller 1c is 4.5 μm, the JIS A hardness is 43, and the electric resistance value is 5.0 ×. 10 ⁶ Ω.

(Comparative Example 1)
Except using the silicone rubber composition (4) which adjusted the addition amount of the platinum catalyst contained in the said silicone rubber composition (1) less than the addition amount in Example 1, it carried out similarly to Example 1, and using it. A conductive roller 1d was produced.

When the vulcanization characteristic tc (10) and viscosity of this silicone rubber composition (4) were measured in the same manner as in Example 1, the vulcanization characteristic tc (10) was 60 (seconds) and the viscosity was 82 Pa · s. Met. The maximum of the average outer diameter of the polishing less elastic layer of the conductive roller 1d _{(diameter, r av)} and an outer diameter accuracy, and the difference between the longest distance _{L 2} and the shortest distance _{L 1 (L} 2 -L ₁₎ When the value and the minimum value, and the shake at this time were measured in the same manner as in Example 1, 20.0 mm, 0.550 to −0.450%, 0.6 mm and 0.16 mm, and 3 0.000% and 0.76%. Further, when measured in the same manner as in Example 1, the surface roughness Rz of the polishing-less elastic layer in the conductive roller 1d is 4.5 μm, the JIS A hardness is 43, and the electric resistance value is 5.0 ×. 10 ⁶ Ω.

  In Examples 1 to 3, the average outer diameter of the polishing-less elastic layers in the conductive rollers 1a to 1c and the vulcanization characteristics tc (10) of the silicone rubber compositions (1) to (3) forming the polishing-less elastic layers. ) And Y = −0.0038X + 20.11, and the relationship of Y = aX + b was satisfied. On the other hand, in Comparative Example 1, the outer diameter of the polishing-less elastic layer in the conductive roller 1d and the vulcanization characteristic tc (10) of the silicone rubber composition (4) forming the polishing-less elastic layer are Y = The relationship of aX + b was not satisfied.

  The conductive rollers 1a to 1d produced in Examples 1 to 3 and Comparative Example 1 are used as developing rollers in the monochrome image forming apparatus 30 containing black developer shown in FIG. 6, and 8000 images are printed. As a result, when the conductive rollers 1a to 1c of Examples 1 to 3 were used, no blurring, “character misalignment”, “white spot” or the like occurred in any image, and high quality was achieved. Whereas the image could be formed, when the conductive roller 1d of Comparative Example 1 was used, “blur”, “character misalignment”, “white spot”, etc. occurred, and the image was high quality. Could not be formed.

  As described above, in Examples 1 to 3, the liquid conductive rubber composition forming the polishing-less elastic layer has a vulcanization characteristic tc (10) corresponding to a desired outer diameter obtained from the relational expression. It has been found that if a silicone rubber composition is selected, the outer diameter of the polishing-less elastic layer obtained by thermoforming can be uniformly adjusted to a desired value as shown in Examples 1 to 3.

  In Examples 1 to 3, when the vulcanization characteristic tc (10) of the silicone rubber composition forming the polishing-less elastic layer is selected within the range of 25 to 45, it is shown in Examples 1 to 3. Thus, it was found that the outer diameter of the polishing-less elastic layer obtained by thermoforming can be adjusted to a desired value and uniformly.

FIG. 1 is a perspective view showing an example of a conductive roller. FIG. 2 is a perspective view showing another example of the conductive roller. FIG. 3 is a graph showing the relationship between the outer diameter of the elastic layer in the conductive roller and the vulcanization characteristic tc (10) in the liquid conductive rubber composition forming the conductive roller. FIG. 4 is a cross-sectional view showing a state in which a mold suitably used in the manufacturing method according to the present invention is assembled. FIG. 5 is a cross-sectional view of the upper end piece constituting the mold suitably used in the manufacturing method according to the present invention. FIG. 6 is a schematic view showing an example of an image forming apparatus according to the present invention. 7A and 7B are explanatory views for explaining the deflection of the polishing-less elastic layer, FIG. 7A is a front view of the conductive roller, and FIG. 7B is a line AA in FIG. 7A. It is sectional drawing.

Explanation of symbols

1A, 1B, 1C Conductive roller 2 Shaft body 2C Shaft body center axis 3, 3B Polishing-less elastic layer 3C Polishing-less elastic layer center point 4 Coat layer 10 Mold 11 Cylindrical hollow body 12 Lower end piece 13 Upper end piece 14 Cavity 15, 17 Holding hole 16 Sprue 18 Vent 18 d Opening 19 Liquid reservoir 30 Image forming apparatus 31 Image carrier 32 Charging means 33 Exposure means 34 Transfer means 35 Fixing means 36 Transfer paper 37 Cleaning means 40 Developing means 41 Developer storage part 42 Developer 43 Stirrer 44 Developer Carrier 45 Developer Restricting Member 46 Blade

Claims (4)

A method for producing a conductive roller comprising a shaft body and a polishing-less elastic layer formed on an outer peripheral surface thereof, and disposed in an image forming apparatus,
From the following formula, a vulcanization characteristic X corresponding to the desired outer diameter of the polishing-less elastic layer is calculated,
Y = aX + b
(Where, a is −0.0046 to −0.0026, b is 20.07 to 20.14, Y is the outer diameter (unit: mm) of the polishing-less elastic layer, and X is the vulcanization characteristic tc. (10) is shown.)
Preparing a liquid conductive rubber composition having a vulcanization characteristic of the calculated X value ± 10;
Next, the liquid conductive rubber composition is injected into a cavity formed by a mold and the shaft body held by the mold, and is heat-molded. The method for producing a conductive roller according to claim 1, wherein the liquid conductive rubber composition is an addition-curable liquid conductive silicone rubber composition . The method for producing a conductive roller according to claim 1, wherein the coating layer forming material applied to the outer peripheral surface of the polishingless elastic layer is cured and / or vulcanized . 4. The polishing-less elastic layer according to claim 1, wherein the outer diameter accuracy is within a range of ± 0.25% and the runout is 0.5% or less. 5. Manufacturing method of conductive roller.

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