JP2008020531A - Developing roller, electrophotographic processing cartridge, and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing roller, an electrophotographic processing cartridge, and image forming device, capable of suppressing toner welding, its plastic deformation, and set lines or welded stripes remaining on the output images, and obtaining high-quality images over a long term. <P>SOLUTION: This developing roller has a center core, an elastic layer and a resin layer formed sequentially on this core. The layered product of the elastic layer and resin layer has a hardness that the pointer is pushed in as deep as 4.0-10.0% of the thickness, when it is loaded to 100 mN/mm<SP>2</SP>by using a universal hardness meter and the distortion is 0.50% or lower of the thickness 30 minutes, after the load is released. The elastic layer has a hardness such that the pointer is pushed into, as deep as 10.0-50.0% of the thickness, when loaded to 100 mN/mm<SP>2</SP>by a universal hardness meter and the distortion is 1.0-10.0% of the thickness 30 minutes, after removing the load. The resin layer has elasticity E' of 10<SP>9</SP>-10<SP>11</SP>Pa at 10 Hz and 20°C, when measurement is made by a tension method. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a developing roller, an electrophotographic process cartridge using the same, and an image forming apparatus.

  As an image formation of an electrophotographic apparatus such as a copying machine or an optical printer, a method using the following process is known. Specifically, a rotatable photoreceptor is uniformly charged by a charging means such as a charging roller, and an electrostatic latent image is formed on the uniformly charged photoreceptor surface by exposure with a laser beam or the like. The photosensitive member and the developing roller are rotated with each other while the developer formed in a thin film on the surface of the developing roller is brought into contact with the photosensitive member carrying the electrostatic latent image. At this time, when a developing bias is applied to the developing roller, the developer moves from the developing roller to the electrostatic latent image on the photosensitive member, and the electrostatic latent image is developed (visualized) as a toner image. Thereafter, the toner image on the photosensitive member is transferred to the recording material in the transfer portion, and fixed on the recording material by heating, pressurizing, or the like in the fixing portion, whereby the image formation on the recording material is completed, and the image forming apparatus It is discharged outside.

  An example of a developing apparatus that supplies a developer to the photosensitive member in such image formation includes an apparatus having the following configuration. A developing roller is provided so as to close the opening of the developer container for storing the developer and to expose a part of the developer container to the outside of the container, and to face the photosensitive member at the exposed part. In the developer container, a toner supply roller for supplying the developer to the developing roller and a developing blade for forming the developer on the developing roller into a thin film are provided. The developing blade is installed in contact with the developing roller in the vicinity of the tip, for example, at a position of 0.1 to 5.0 mm from the tip, and the developer on the developing roller supplied by the toner supply roller has a uniform thickness. The thin film is formed.

  As the developing roller used in the developing device, an elastic roller having an electric resistance in a semiconductive region is used, and the roller is pressed against the photosensitive member, the developing blade, and the toner supply roller, and is applied with a voltage. When the stress on the toner by the developing roller increases, the developer is fused to the surface of the developing roller, and an image defect called a so-called fusion streak may occur at the fused portion of the developer. In order to suppress the fusion of the toner to the developing roller, a method of forming the developing roller with a low hardness material is effective.

  However, in a developing roller formed of a low-hardness material, if the image forming apparatus is not operated for a long time without being operated, a certain position of the developing blade, the photosensitive member, etc. will come into contact with the plastic roller for a long time. Deformation occurs. Thereafter, when the image forming apparatus is operated to output an image, an image defect called a set trace image tends to occur on the image. The set trace image is a horizontal line-shaped image defect that occurs in correspondence with the part where the developing roller and the photosensitive member or the developing blade are in contact with each other, and appears as a dark horizontal line streak in the halftone image or solid image. is there. The plastic deformation generated in the developing roller due to the contact pressure of the photosensitive member or the like can be suppressed by increasing the hardness of the developing roller, and the set trace image can be suppressed.

  As described above, in the developing roller, the countermeasures against the suppression of developer fusion and the suppression of set trace images due to plastic deformation are contradictory, and low compression set that is low in hardness but difficult to plastically deform. In addition, there is a need for a developing roller with little variation in electrical characteristics.

  In order to meet this requirement, various attempts have been made to improve the material of the developing roller. As a developing roller with low hardness and low compression set, an organic gel layer in which a specific polymer is swollen with a plasticizer is formed as an elastic layer on the surface of the shaft core, and a cover layer and a resin layer are formed on the outer periphery. A developed developing roller has been reported (Patent Document 1).

However, when a developing roller is produced using a polymer having only a few crosslinking points in order to reduce the hardness, compression set is deteriorated. For this reason, the deformation amount of the contact portion increases due to long-term contact with the developing blade, and a set trace image defect may occur. In the developing roller described in Patent Document 1, a cover layer is required for the purpose of suppressing the volatilization and leakage of the plasticizer, and there is a problem that the production efficiency is lowered.
JP 2003-241465 A

  It is an object of the present invention to suppress toner fusion, suppress plastic deformation, suppress set trace images and fusion streak images in output images, suppress exudation of plasticizers, etc., and maintain high quality over a long period of time. An object of the present invention is to provide a developing roller having high stability as a member capable of obtaining an image. Furthermore, an electrophotographic process cartridge capable of suppressing a set trace image and a fusion streak image in an output image, suppressing contamination due to exudation of a plasticizer or the like from a developing roller, and obtaining a high-quality image over a long period of time, An object is to provide an image forming apparatus.

  The present inventors have obtained the knowledge that the above-mentioned problem can be solved by providing a resin layer having a high elastic modulus for the deterioration of compression set due to the lower hardness of the elastic layer. In other words, the high elastic modulus resin layer reduces the amount of plastic deformation in the developing roller due to long-term contact with the developing blade and the photoconductor, and the elastic layer has low hardness, so the hardness of the developing roller does not increase, and the fogging Also found that it can be suppressed. Based on this knowledge, the present invention has been completed.

That is, according to the present invention, in a developing roller having a shaft core, an elastic layer sequentially provided on the shaft core, and a resin layer, the laminate of the elastic layer and the resin layer is 100 mN by a universal hardness meter. The indenter indentation depth ratio is 4.0 to 10.0% of the thickness when a load of / mm ² is applied, and the strain ratio 30 minutes after the load is released is 0. 0% of the thickness. 50% or less, and when the elastic layer is applied with a load of 100 mN / mm ² by a universal hardness tester, the indenter depth ratio is 10.0 to 50.0% of the thickness, and the load is released. The elastic modulus E ′ measured by a tensile method at a frequency of 10 Hz and a temperature of 20 ° C. is 10 ⁹ to 10 ¹¹ Pa. The present invention relates to a developing roller.

  The present invention also relates to a method for producing the developing roller, wherein the silicone material is cured by an addition reaction by heating.

  The present invention also provides an electrophotographic process having a developing roller that is detachably provided in an electrophotographic apparatus, supplies a developer formed in a thin film shape to the photoreceptor, and develops an electrostatic latent image carried by the photoreceptor. The present invention relates to an electrophotographic process cartridge, wherein the developing roller is the developing roller.

  In addition, the present invention provides an image forming apparatus including a photosensitive member carrying an electrostatic latent image and a developing roller for supplying the developer formed in a thin film to the photosensitive member and developing the electrostatic latent image carried by the photosensitive member. The present invention relates to an image forming apparatus, wherein the developing roller is the developing roller.

  The developing roller of the present invention suppresses toner fusing, suppresses plastic deformation, suppresses set trace images and fusing stripe images in the output image, suppresses exudation of plasticizers, etc., and provides high quality over a long period of time. It is also highly stable as a member capable of obtaining the above image. The electrophotographic process cartridge and the image forming apparatus of the present invention suppress the set trace image and the fusion streak image in the output image, suppress the contamination due to the exudation of the plasticizer from the developing roller, and the high-quality image for a long time. Can be obtained.

The developing roller of the present invention is a developing roller having a shaft core body, an elastic layer sequentially provided on the shaft core body, and a resin layer, and the laminate of the elastic layer and the resin layer is formed by a universal hardness meter. When the load of 100 mN / mm ² is applied, the indentation depth rate is 4.0 to 10.0% of the thickness, and the strain rate after 30 minutes from the release of the load is 0% of the thickness. .50% or less, and the elastic layer has an indenter depth ratio of 10.0 to 50.0% of the thickness when a load of 100 mN / mm ² is applied by a universal hardness meter. The elastic modulus E ′ measured by the tensile method at a frequency of 10 Hz and a temperature of 20 ° C. is 10 ⁹ to 10 ^11. It is characterized by Pa.

  The shaft core body in the developing roller of the present invention has strength capable of supporting the upper elastic layer and resin layer, and has conductivity. Examples of the material of the shaft core include alloys such as carbon steel, iron, steel, aluminum, titanium, copper and nickel, and alloys such as stainless steel, duralumin, brass and bronze containing these metals. Further, a rigid and conductive resin such as a composite material obtained by solidifying carbon black or carbon fiber with a plastic can be used. Among these, carbon steel alloys and the like can be used as preferable from the viewpoint of strength.

  Further, the shaft core is preferably subjected to a rust prevention treatment, and specifically, a shaft subjected to a plating treatment or an oxidation treatment can be used. As such plating treatment, industrial nickel plating can be mentioned as a preferable one, and the plating thickness can be set to 5 μm, for example.

  The axial body may be any of a columnar shape, a cylindrical shape, etc., but a columnar shape is more preferable. Examples of the outer diameter include 6 to 8 mm. If the outer diameter of the shaft core body is 6 mm or more, the shaft body has sufficient rigidity, the deflection of the developing roller during image formation can be suppressed, and a uniform image density can be obtained over the longitudinal direction of the roller. If the outer diameter of the shaft core is 8 mm or less, the entire volume can be kept low, and a sufficiently thick elastic layer can be secured.

The elastic layer in the developing roller of the present invention has an elastic modulus capable of reducing stress applied to the toner and suppressing compression set due to pressure contact with the developing blade. Such an elastic layer has a hardness such that the indentation depth ratio when the load of 100 mN / mm ² is applied for 1 minute by a universal hardness meter is 10.0 to 50.0% of the thickness of the elastic layer. . Specifically, for example, when the thickness of the elastic layer is ² to 5 mm, it is preferable that the indenter indentation depth is 500 to 1000 μm when a load of 100 mN / mm ^{2 is} applied for 1 minute by a universal hardness meter. . When the indentation depth ratio when the load is applied is 10.0% or more of the thickness of the elastic layer, the stress applied to the toner can be suppressed, and streaks due to toner fusion in the obtained image can be suppressed. Occurrence can be suppressed. In addition, if the indentation depth ratio when the load is applied is 50.0% or less of the thickness of the elastic layer, the shape of the elastic layer is maintained and a low compression set is obtained. Generation of trace images can be suppressed. In the case where the indentation depth of the indenter when the load is applied is an elastic layer having a thickness of 2 to 5 mm, such an effect can be obtained more remarkably if it is 500 μm or more and 1000 μm or less.

The elastic layer is added 100 mN / mm ² load in one minute by the universal hardness tester, after the load reached 100 mN / mm ^2, 30 minutes after the time the removal of the load of the 100 mN / mm ² at 1 minute The strain rate is 1.0 to 10% of the thickness of the elastic layer. Specifically, for example, when the thickness of the elastic layer is 2 to 5 mm, the thickness is preferably 50 to 200 μm. If the strain rate after 30 minutes from the removal of the weight is 1.0% or more of the thickness of the elastic layer, the stress applied to the toner can be suppressed, and streaks due to toner fusion in the resulting image can be suppressed. Occurrence can be suppressed. If the strain rate after 30 minutes from the removal of the weight is 10.0% or less of the thickness of the elastic layer, a low compression set can be obtained, and the occurrence of a set trace image can be suppressed in the obtained image. . In the case of an elastic layer having a thickness of 2 to 5 mm after the removal of the weight, the effect can be obtained more remarkably if the strain is 50 μm or more and 200 μm or less.

  Here, as the universal hardness meter, a commercially available one, for example, a surface film physical property tester Fischerscope H100C manufactured by Fischer can be used, and measured values obtained at room temperature, for example, 23 ° C. can be adopted.

  Specific examples of the material for forming such an elastic layer include compositions containing silicone gel, urethane gel, polystyrene gel, polyester gel, vinyl acetate copolymer gel, polyvinyl chloride gel, neoprene gel, and the like. Can do. Of these, the adjustment to the above elastic modulus is easy, excellent workability, no by-products due to the curing reaction, no dimensional stability, good physical properties after curing For these reasons, the addition reaction type silicone gel composition can be mentioned as a particularly preferable one.

  Examples of the silicone gel composition include an organopolysiloxane (A) having two or more alkenyl groups in one molecule, and an organohydrogensiloxane having two or more hydrogen atoms bonded to silicon atoms in one molecule ( Those containing B) and a platinum-based catalyst (C) are preferred.

  The organopolysiloxane (A) is a main component of silicone gel, and the molecular structure may be any of linear, branched, cyclic, and network. The organopolysiloxane (A) preferably has at least two alkenyl groups in one molecule. Examples of the alkenyl group of the organopolysiloxane (A) include a vinyl group, an allyl group, and a propenyl group, and among these, a vinyl group is particularly preferable. The bonding position of the alkenyl group in the organopolysiloxane (A) may be either the silicon atom at the end of the molecular chain or the silicon atom in the molecular chain, or may be bonded to both. Examples of the substituent other than the alkenyl group in the organopolysiloxane (A) include, for example, an alkyl group such as methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, phenyl group, tolyl group, Examples thereof include aryl groups such as xylyl group and naphthyl group, aralkyl groups such as benzyl group and phenylethyl group, and halogenated alkyl groups such as chloromethyl group and bromoethyl group. Among these, a methyl group and a phenyl group are particularly preferable.

  The molecular weight of the organopolysiloxane (A) is preferably, for example, 6,000 to 1,000,000, and more preferably 12,000 to 500,000, for the cured product to be a gel-like elastic body. . If the molecular weight is 6,000 or more, the resulting elastic layer can be prevented from becoming highly hard and stress applied to the toner can be suppressed, and if the molecular weight is 1,000,000 or less, work can be performed. It is possible to suppress the deterioration of the property.

  Here, as the molecular weight, a high-performance liquid chromatograph analyzer HLC-8120GPC manufactured by Tosoh was used, and a weight average molecular weight determined in terms of polystyrene was used as a solvent under conditions of tetrahydrofuran, a measurement temperature of 40 ° C., and a flow rate of 0.6 ml / min. can do.

  The organohydrogensiloxane (B) contained in the addition reaction type silicone gel composition is used as a crosslinking agent for the organopolysiloxane (A), and the molecular structure thereof is linear, branched or cyclic. Any of the meshes may be used. Such organohydrogensiloxane (B) preferably has at least two hydrogen atoms bonded to silicon atoms in one molecule. The bonding position of the silicon atom-bonded hydrogen atom of the organohydrogensiloxane (B) may be either the silicon atom at the end of the molecular chain or the silicon atom in the molecular chain, or may be bonded to both. Other substituents include, for example, alkyl groups such as methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group and heptyl group, aryl groups such as phenyl group, tolyl group, xylyl group and naphthyl group, Examples thereof include aralkyl groups such as benzyl group and phenylethyl group, and halogenated alkyl groups such as chloromethyl group and bromoethyl group. Among these, a methyl group and a phenyl group are particularly preferable.

  The molecular weight of the organohydrogensiloxane (B) is preferably 500 to 1,000,000, particularly 2,500 to 200,000. When the molecular weight of the organohydrogensiloxane (B) is 500 or more, volatilization can be suppressed, and the resulting silicone gel composition can be prevented from becoming unstable. Moreover, if the molecular weight of the organohydrogensiloxane (B) is 1,000,000 or less, it is possible to suppress a decrease in workability.

  The content of the organohydrogensiloxane (B) in the silicone gel composition is such that when the organopolysiloxane (A) is 100 parts by weight, the b / a is 0.1 to 5.0 parts by weight. Is preferred. Here, b represents the total number of hydrogen atoms bonded to silicon atoms in the organohydrogensiloxane (B), and a represents the total number of alkenyl groups in the organopolysiloxane (A). That is, the amount is such that the silicon-bonded hydrogen atom in the organohydrogensiloxane (B) is 0.1 to 5.0 mol with respect to 1 mol of the alkenyl group in the organopolysiloxane (A). If the silicon atom-bonded hydrogen atom in the organohydrogensiloxane (B) component is 0.1 mol or more with respect to 1 mol of the alkenyl group in the organopolysiloxane (A), sufficient crosslinking is achieved in the silicone gel composition. It is formed. Moreover, if the silicon atom bond hydrogen atom in an organohydrogensiloxane (B) component is 5.0 mol or less, the heat resistant fall of the silicone gel obtained after bridge | crosslinking of a silicone gel composition can be suppressed.

  The platinum-based catalyst (C) contained in the silicone gel composition is a catalyst for promoting the crosslinking of the silicone gel composition. Examples of the platinum catalyst (C) include platinum fine powder, platinum black, platinum-supported silica fine powder, platinum-supported activated carbon, chloroplatinic acid, platinum tetrachloride, chloroplatinic acid alcohol solution, platinum and olefin complex. And platinum and alkenylsiloxane complexes. Furthermore, a thermoplastic resin powder having a particle diameter of less than 10 μm, such as a polystyrene resin, a nylon resin, a polycarbonate resin, and a silicone resin containing these platinum-based catalysts can be exemplified.

  The content of the platinum-based catalyst (C) in the silicone gel composition is preferably an amount sufficient to form a crosslink of the organopolysiloxane (A) and the organohydrogensiloxane (B). Specifically, in this silicone gel composition, the amount of platinum metal in the platinum-based catalyst (C) is preferably 0.1 to 1,000 ppm by weight, and particularly preferably 1 to 500 ppm. Preferably there is. If the platinum metal in the platinum-based catalyst (C) contained in the silicone gel composition is 0.1 ppm or more by weight, the crosslinking reaction of the silicone gel composition can be efficiently advanced. Moreover, if this is 1000 ppm or less, useless use can be suppressed and coloring etc. of the silicone gel crosslinked product obtained can be suppressed.

  The elastic layer may contain various additives as necessary as long as the functions of the inclusions are not impaired. Specific examples include various additives such as a conductive agent and a non-conductive filler.

Conductive agents added for the purpose of imparting conductivity to the elastic layer include various conductive metals or alloys such as carbon black, graphite, aluminum, palladium, silver, iron, copper, tin, and stainless steel, tin oxide, and zinc oxide. , Indium oxide, titanium oxide, antimony oxide, molybdenum oxide, tin oxide-antimony oxide solid solution, various conductive metal oxides such as tin oxide-indium oxide solid solution, and insulating materials coated with these conductive materials Powder can be used. Furthermore, examples of the ionic conductive agent include perchlorates such as LiClO ₄ and NaClO _{4 and} quaternary ammonium salts. Among these, carbon black can be suitably used because it can be obtained relatively easily and good chargeability can be obtained regardless of the type of material.
Other non-conductive fillers include diatomaceous earth, quartz powder, dry silica, wet silica, titanium oxide, zinc oxide, aluminosilicate, calcium carbonate, zirconium silicate, aluminum silicate, talc, alumina, iron oxide, etc. be able to.

The elastic layer preferably has a volume resistivity of 10 ³ to 10 ¹⁰ Ω · cm when a DC voltage of 100 V is applied. If the volume resistivity of the elastic layer is 1 × 10 ³ to 1 × 10 ¹⁰ Ω · cm, the toner can be uniformly charged. For example, when carbon black is used in the silicone gel composition, the amount of the conductivity-imparting agent used to make the elastic layer have such a volume resistivity value is 5 with respect to 100 parts by mass of the resin component. It can be set to -20 mass parts.

  Here, when measuring the volume resistivity of the elastic layer, the elastic layer material is cured under the same conditions as those for forming the elastic layer to produce a 2.0 mm thick elastic layer test piece. To make measurements. Specifically, the elastic layer material is formed into a sheet and placed in a 130 ° C. oven for 20 minutes to form two 2.0 mm thick sheets, and then heated in a 200 ° C. oven for 4 hours for secondary vulcanization. I do. After that, the sheet is left in an environment of temperature 25 ° C. and humidity 45% for 24 hours or more, and measured by applying a voltage of 100 V using Hiresta IP (manufactured by Mitsubishi Oil Chemical Co., Ltd.). The volume resistivity can be obtained as an average value.

  The thickness of the elastic layer is not limited, but is preferably 2 to 5 mm. If the thickness of the elastic layer is 2 mm or more, the development roller can be prevented from becoming hard due to the influence of the shaft core, and the toner can be prevented from being fused to the surface of the development roller. it can. Moreover, if the thickness of an elastic layer is 5 mm or less, the shape as a developing roller can be hold | maintained easily.

  The resin layer in the developing roller of the present invention is provided on the elastic layer so as to impart high elasticity to the developing roller and to suppress the occurrence of set trace image defects in the obtained image. Further, it is provided to suppress bleeding out of the plasticizer and the like contained in the elastic layer to the surface of the developing roller, to suppress contamination of the photoreceptor, and to adjust the electric resistance of the entire developing roller.

Such a resin layer has an elastic modulus E ′ measured by a tensile method at a frequency of 10 Hz and a temperature of 20 ° C. of 10 ⁹ to 10 ¹¹ Pa. If the elastic modulus of the resin layer is 10 ⁹ Pa or more, plastic deformation due to pressure contact with the developing blade or the like can be suppressed, and the generation of set trace images can be suppressed. Further, when the elastic modulus of the resin layer is 10 ¹¹ Pa or less, the occurrence of toner fusion due to the high hardness of the developing roller can be suppressed.

  Here, the elastic modulus E ′ was measured using a dynamic viscoelasticity test apparatus (DVA-220: manufactured by IT Measurement & Control Co., Ltd.) based on JIS K6394 “Testing method for dynamic properties of vulcanized rubber”. A value measured at 20 ° C. can be adopted.

  Examples of the material for forming the resin layer include polyurethane resin, acrylic resin, polyimide resin, fluorine resin, polyamide resin, silicone resin, polyester resin, epoxy resin, polyether resin, amino resin, and the like. These can be used alone or in combination of two or more. Further, these resins include those having reactive groups such as hydroxyl group, carboxyl group, acid anhydride group, amino group, imino group, isocyanate group, methylol group, alkoxy group, aldehyde group, epoxy group, unsaturated group. preferable. Among these, in particular, one or a mixture of two or more of a polyurethane resin, an acrylic resin, and a polyimide resin is preferable because it can be easily adjusted as having a desired elasticity and hardness in the developing roller.

  Fine particles having a volume average particle diameter of 1 to 20 μm can be dispersed in the resin layer. The resin layer in which the fine particles are dispersed has a surface roughness that facilitates the conveyance of the toner, and a sufficient amount of toner can be conveyed to the development area. Examples of the fine particles dispersed in the resin layer include plastic pigments such as polymethyl methyl methacrylate fine particles, silicone rubber fine particles, polyurethane fine particles, polystyrene fine particles, amino resin fine particles, and phenol resin fine particles. Among these, polymethyl methyl methacrylate fine particles and polyurethane fine particles are particularly preferable, and these fine particles are added in a range of about 20 to 200% by mass with respect to the total mass of the resin layer constituting components excluding these fine particles. Thus, a preferable surface roughness can be obtained.

  Furthermore, a conductive agent can be blended in the resin layer in order to adjust the electrical resistance of the entire developing roller. As the conductive agent, carbon black, graphite, conductive metal oxide, copper, aluminum, nickel, iron powder, etc., which are conductive agents having various electron conduction mechanisms, or alkali metal salts and ammonium salts, which are ionic conductive agents Fine particles such as these can be used. The conductive agent preferably has an average particle size of 0.08 μm or less in order to facilitate control of the surface shape of the resin layer without affecting the formation of surface irregularities on the resin layer.

The volume resistivity value of the resin layer is preferably in the range of 10 ⁶ to 10 ¹⁰ Ω · cm when a DC voltage of 100 V is applied. When the volume resistivity value of the resin layer is 10 ⁶ to 10 ¹⁰ Ω · cm, the toner can be uniformly charged. For example, in the case of carbon black, the amount of the conductive agent used to make the resin layer have such a volume resistivity value can be 15 to 80 parts by mass with respect to 100 parts by mass of the resin component. .

  In terms of the thickness of the resin layer, in relation to the elastic layer, the developing roller has a desired elasticity and hardness, and from the viewpoint of preventing contamination of the photoreceptor due to bleed out of the plasticizer from the elastic layer. 5 μm or more is preferable. Further, from the viewpoint of suppressing the occurrence of toner fusion due to the increased hardness of the developing roller, the thickness is preferably 500 μm or less. A more preferable range of the thickness of the resin layer is 10 to 30 μm.

In such a laminate of the resin layer and the elastic layer in the developing roller of the present invention, as the laminate, an indenter indentation depth rate when a load of 100 mN / mm ² is applied for 1 minute by a universal hardness meter Has a hardness of 4.0 to 10.0% of the thickness of the laminate. Specifically, for example, when the thickness of the elastic layer is ² to 5 mm, it is preferable that the indenter push-in depth is 200 to 500 μm when a load of 100 mN / mm ^{2 is} applied to the laminate in one minute. If the indenter depth ratio when the load is applied is 4.0% or more of the thickness of the laminate, the stress applied to the toner can be suppressed, and streaks due to toner fusion in the resulting image can be suppressed. Occurrence can be suppressed. Also, if the indentation depth ratio when the load is applied is 10.0% or less of the thickness of the laminated body, the compression set is low compression set and the generation of set trace images in the obtained image is suppressed. Can do. In the case where the indentation depth of the indenter when the load is applied is 2 to 5 mm in thickness of the elastic layer, such an effect can be obtained more remarkably if it is 200 μm or more and 500 μm or less.

Further, since the laminate of the elastic layer and the resin layer is added 100 mN / mm ² load at 1 minute, after the load reached 100 mN / mm ^2, after removing a load of this 100 mN / mm ² at 1 minute It has elasticity that the strain rate after 30 minutes is 0.50% or less of the thickness of the laminate. Specifically, for example, when the thickness of the elastic layer is 2 to 5 mm, it is preferably 10.0 μm or less of the laminate. If the strain rate after 30 minutes from the removal of the weight is 0.50% or less of the thickness of the laminate, the compression set is low compression set, and the generation of set trace images in the obtained image can be suppressed. . When the strain 30 minutes after the weight is removed is 10.0 μm or less when the elastic layer has a thickness of 2 to 5 mm, such an effect can be obtained more remarkably.

  As a method for producing the developing roller of the present invention, in order to form an elastic layer on the surface of the shaft core, a method in which the silicone gel composition is cured by an addition reaction by heating is preferable. For example, the silicone gel composition is molded by various molding methods such as extrusion molding, press molding, injection molding, liquid injection molding, cast molding, and the like, and an appropriate temperature, specifically, 100 to 150 ° C., 10 minutes to 3 There is a method in which an elastic layer is formed on the surface of the shaft core body by heating and curing with time. In particular, in the method of forming an elastic layer around an axial core body by injecting an uncured material into a cylindrical mold and then heating, the roller shape is a certain shape of the cylindrical mold to be used. Since reproduction is performed under the contraction amount, it is possible to obtain one having a sufficiently satisfactory shape accuracy.

  As a method for forming a resin layer on the elastic layer thus formed, a coating liquid containing the above-mentioned uncured resin is prepared, and a coating film is formed by a method such as immersion, application, spraying, etc. And the method of heating and hardening this can be mentioned.

  As an example of such a developing roller of the present invention, those shown in the schematic sectional view of FIG. 1 and the perspective view of FIG. 2 can be exemplified. The developing roller shown in FIGS. 1 and 2 includes a shaft core body 15, and an elastic layer 16 and a resin layer 17 that are sequentially formed concentrically on the outer periphery of the shaft core body 15.

  As the developing roller of the present invention, the elastic layer and the resin layer may each be composed of a plurality of different materials, and in addition to these layers, there are various types such as easy chargeability and friction resistance. It may have a functional layer having a function.

  The image forming apparatus of the present invention includes a photosensitive member that carries an electrostatic latent image, and a developing roller that supplies the developer formed in a thin film to the photosensitive member and develops the electrostatic latent image carried by the photosensitive member. In the image forming apparatus, the developing roller is the developing roller. As an example, the image forming apparatus shown in FIG. 3 can be cited. The image forming apparatus shown in the schematic configuration diagram of FIG. 3 is provided with a photoreceptor 1 as an electrostatic latent image carrier that rotates in the direction of the arrow. Around the photosensitive member, there are a charging roller 2 for uniformly charging the photosensitive member, an exposure means for irradiating the uniformly charged photosensitive member with a laser beam 3 to form an electrostatic latent image, and an electrostatic latent member. A developing device is provided that supplies toner to the photoreceptor on which the image is formed to develop the electrostatic latent image. In the developing device, a developer container 14 containing a non-magnetic toner 8 as a one-component toner, and an opening of the developer container are closed so that the exposed portion from the developer container faces the photoconductor. A developing roller 5 is provided. In the developer container, the toner is supplied to the developing roller, and at the same time, the toner supply roller 6 that scrapes off the residual toner that is not used on the developing roller, and the toner on the developing roller is formed into a thin film, and triboelectric charging is performed. A developing blade 7 is provided. The toner made into a thin film on the developing roller moves to an electrostatic latent image on the photoconductor facing the developing roller, and a toner image is formed on the photoconductor.

  On the other hand, a recording material 13 such as paper supplied by a paper feeding roller is transported between a transfer roller 9 to which a transfer bias power is applied and a photosensitive member, and here, the transfer bias charge applied from the back surface of the recording material is used for photosensitive. The toner image on the body moves onto the recording material. The toner image on the recording material is heated and pressed between the fixing roller and the pressure roller to be fixed on the recording material, and the image formation is completed.

  On the other hand, a cleaning blade 10 is provided for removing residual toner that has not been transferred onto the photoreceptor and cleaning the surface, and a waste toner container 11 for storing waste toner scraped off from the photoreceptor is provided. The cleaned photoconductor is set in an image-formable state and stands by.

  In addition, the electrophotographic process cartridge of the present invention is provided with a developing roller that is detachably attached to the electrophotographic apparatus, and that supplies a developer formed in a thin film shape to the photoreceptor and develops the electrostatic latent image carried by the photoreceptor. An electrophotographic process cartridge having a developing roller is the developing roller. As an example, for example, in FIG. 3, a charging roller 2, a photoreceptor 1, a developing roller 5, a toner supply roller 6, a developing blade 7, a stirring blade, and a developer container 14 that stores toner are included. Examples thereof include an integrated unit that is detachably provided in the image forming apparatus. Since the function of each member is the same as that in the image forming apparatus, description thereof is omitted. In addition to the above, the electrophotographic process cartridge of the present invention is replaced with one or two or more of the above-mentioned members together with the above-mentioned members such as a transfer roller and a cleaning blade for transferring the toner image on the photosensitive member to the recording material. And may be provided integrally.

  Hereinafter, the developing roller, the electrophotographic process cartridge, and the electrophotographic image forming apparatus of the present invention will be described in detail, but the technical scope of the present invention is not limited thereto. Hereinafter, “part” means “part by mass”.

[Example 1]
Primer treatment was performed on the surface of a SUM shaft core having a diameter of 6 mm and a length of 250 mm for the purpose of improving the adhesion to silicone rubber.

[Preparation of elastic layer]
100.0 parts dimethylpolysiloxane (having vinyl groups at both ends of the molecular chain, weight average molecular weight 18,000), 5 parts of crystalline silica, 5 parts of carbon black (Denka Black, powdered product manufactured by Denki Kagaku Kogyo), Organohydrogenpolysiloxane (having SiH groups at both ends and side chains of molecular chain, weight average molecular weight 500) 3.0 parts (1.1 mol of SiH groups per 1 mol of vinyl groups of dimethylpolysiloxane) And 0.1 part of a platinum compound (Pt concentration 1%) was blended to obtain a liquid composition.

  An axial core is placed in the center of the cylindrical mold, and this liquid composition is injected into the cylindrical mold from the injection port, cured by heating at 130 ° C. for 20 minutes, and further post-cured at 200 ° C. for 4 hours. Thus, an elastic layer having a thickness of 5 mm was obtained.

[Measurement of hardness with universal hardness tester]
For the obtained elastic layer, the indenter indentation depth when a load of 100 mN / mm ² was applied and the amount of strain 30 minutes after releasing the load were measured using a Fischer surface film property tester Fischerscope H100C. Measured. The indenter was a square pyramidal diamond, and the load was increased or decreased at a speed of ± 100 (mN / mm ² ) /1.0 (min). The results are shown in Table 1.

[Preparation of resin layer]
MEK was added to 100 parts of acrylic polyol (Daicel Chemical Industries DC2016), 102 parts of urethane-modified polymeric MDI (Nihon Polyurethane Industry Coronate 2520), and 20 parts of carbon black (Mitsubishi Chemical MA-100). After being dispersed and rotated by a ball mill for 5 hours, 35 parts of urethane fine particles having an average particle diameter of 10 μm were added and again dispersed and rotated for 1 hour. An elastic layer was immersed in this solution to form a coating film, and after air drying, a resin layer of acrylic resin having a thickness of 20 μm was prepared by heat treatment at 140 ° C. for 4 hours to obtain a developing roller.

The sheet | seat was produced with the resin layer single-piece | unit, and elastic modulus E 'was measured at the frequency of 10 Hz, and the temperature of 20 degreeC using the dynamic viscoelasticity measuring apparatus DVA-220 by IT measurement control company. It was 9.4 × 10 ¹⁰ Pa. The resin layer was peeled off by laser processing from the obtained developing roller, and the result was 9.1 × 10 ¹⁰ Pa.

About the obtained laminate of the resin layer and the elastic layer, the indenter indentation depth when a load of 100 mN / mm ² was applied and the amount of strain 30 minutes after releasing the load were measured in the same manner as described above. The results are shown in Table 1.

[Image evaluation]
[Set trace image]
The obtained developing roller is mounted on an electrophotographic process cartridge, and the developing roller is 40 ° C. and 95% R.D. It was left for one month in an H environment. After that, a developing roller was attached to a newly prepared electrophotographic process cartridge, and this was attached to an electrophotographic laser beam printer for A4 size output, recording medium output speed A4 vertical 16 sheets / min, and image resolution 600 dpi. . The photoreceptor has a charge transport layer using a modified polycarbonate as a binder resin by a reversal development method in which an aluminum cylinder is coated with an OPC (organic photoconductor) layer. The obtained image was evaluated according to the following criteria. The results are shown in Table 1.

  X: Level at which a clear horizontal streak occurs in the developing roller pitch, which is a practical problem.

  Δ: Horizontal streaks are generated but there is no practical problem.

○: No horizontal stripes are seen.
[Toner fused image]
The developing roller is mounted on the above-mentioned electrophotographic laser beam printer, and after 10,000 images that draw a horizontal line with a width of 2 dots and a spacing of 50 dots are output continuously, a horizontal line with a width of 1 dot and a spacing of 2 dots is drawn. An image was output. The obtained image was evaluated according to the following criteria. The results are shown in Table 1.

  X: Level at which many vertical streaks are seen in the same direction as the image printing direction by fusing toner to the developing roller surface or blade.

  Δ: Vertical streaks are observed, but there is no practical problem.

  ○: Level at which no vertical stripes can be seen.

[Example 2]
Primer treatment was performed on the surface of the SUM shaft core having a diameter of 8 mm and a length of 250 mm for the purpose of improving the adhesiveness to the silicone rubber.

[Preparation of elastic layer]
100.0 parts of dimethylpolysiloxane (having vinyl groups at both ends of the molecular chain, weight average molecular weight 86,000), 5 parts of crystalline silica, 5 parts of carbon black (Denka Black, powdered product manufactured by Denki Kagaku Kogyo), 10.1 parts of organohydrogenpolysiloxane (having SiH groups at both molecular chain terminals and side chains, weight average molecular weight 7,800) (1.1 mol of SiH groups relative to 1 mol of vinyl groups of dimethylpolysiloxane) And 0.1 part of a platinum compound (Pt concentration 1%) was blended to obtain a liquid composition.

  An axial core is placed in the center of the cylindrical mold, and this liquid composition is injected into the cylindrical mold from the injection port, cured by heating at 130 ° C. for 20 minutes, and further post-cured at 200 ° C. for 4 hours. Thus, an elastic layer having a thickness of 4 mm was formed.

For the obtained elastic layer, the indenter indentation depth when a load of 100 mN / mm ² was applied and the amount of strain 30 minutes after releasing the load were measured in the same manner as in Example 1. The results are shown in Table 1.

[Preparation of resin layer]
MEK was added to 100 parts of acrylic polyol (Hitaloid 3368 manufactured by Hitachi Chemical Co., Ltd.), 57 parts of urethane-modified polymeric MDI (Coronate 2520 manufactured by Nippon Polyurethane Industry) and 16 parts of carbon black (MA-100 manufactured by Mitsubishi Chemical). After being dispersed and rotated by a ball mill for 5 hours, 18 parts of urethane fine particles having an average particle diameter of 10 μm were added and again dispersed and rotated for 1 hour. An elastic layer was immersed in this solution to form a coating film. After air drying, an acrylic resin resin layer having a thickness of 18 μm was prepared as a resin layer by heat treatment at 140 ° C. for 4 hours to obtain a developing roller.

[Measurement of hardness and elastic modulus, characteristic image formation]
A sheet was produced with the resin layer alone, and its elastic modulus E ′ was measured to be 2.1 × 10 ⁹ Pa. It was 1.8 * 10 < ⁹ > Pa when the resin layer was peeled off by laser processing from the obtained developing roller and measured.

About the obtained elastic layer and the laminate of the resin layer and the elastic layer, the indenter indentation depth when a load of 100 mN / mm ² was applied in the same manner as in Example 1, and the distortion 30 minutes after releasing the load The amount was measured and the elastic modulus of the resin layer was measured. Further, image formation was performed in the same manner as in Example 1, and the set trace image and the toner fused image were evaluated for the obtained image. The results are shown in Table 1.

[Example 3]
[Preparation of developing roller]
As an elastic layer, 100.0 parts of dimethylpolysiloxane (having vinyl groups at both ends of the molecular chain, weight average molecular weight 86,000), 5 parts of crystalline silica as filler, carbon black (Denka Black manufactured by Denki Kagaku Kogyo) 5 parts of an organohydrogenpolysiloxane (having SiH groups at both ends and side chains of the molecular chain and a weight average molecular weight of 2,300) 2.9 parts (based on 1 mol of vinyl group of dimethylpolysiloxane) Example 2 except that a liquid composition obtained by blending 0.1 part of a platinum compound (Pt concentration 1%) as a curing catalyst was used in an amount of 1.1 mol of SiH groups. In the same manner as above, a developing roller was obtained.

[Measurement of hardness and elastic modulus, characteristic image formation]
About the obtained elastic layer, the laminate of the elastic layer and the resin layer, the indenter indentation depth when a load of 100 mN / mm ² was applied and the amount of strain 30 minutes after releasing the load were the same as in Example 1. The elastic modulus of the resin layer was measured. Further, image formation was performed in the same manner as in Example 1, and the set trace image and the toner fused image were evaluated for the obtained image. The results are shown in Table 1. The results are shown in Table 1.

[Example 4]
[Preparation of developing roller]
As a resin layer, a developing roller was obtained in the same manner as in Example 3 except that the amount of urethane-modified polymeric MDI (Nihon Polyurethane Industry Coronate 2520) added was changed to 45 parts.

[Measurement of hardness and elastic modulus, characteristic image formation]
A sheet was produced with the resin layer alone, and its elastic modulus E ′ was measured to be 1.1 × 10 ⁹ Pa. It was 1.0 × 10 ⁹ Pa when the resin layer was peeled off from the obtained developing roller by laser processing and measured.

For the laminate of the obtained resin layer and elastic layer, the indenter indentation depth when a load of 100 mN / mm ² was applied and the amount of strain 30 minutes after releasing the load were measured in the same manner as in Example 1. The elastic modulus of the resin layer was measured. Further, image formation was performed in the same manner as in Example 1, and the set trace image and the toner fused image were evaluated for the obtained image. The results are shown in Table 1.

[Example 5]
Primer treatment was performed on the surface of the SUM shaft core having a diameter of 8 mm and a length of 250 mm for the purpose of improving the adhesiveness to the silicone rubber.

[Preparation of developing roller]
100.0 parts of dimethylpolysiloxane (having vinyl groups at both ends of the molecular chain, weight average molecular weight 930,000), 5 parts of crystalline silica as filler, carbon black (Denka black, powdered product manufactured by Denki Kagaku Kogyo) ) 5 parts, organohydrogenpolysiloxane (having SiH groups at both ends and side chains, weight average molecular weight 300) 1.6 parts (5 moles of SiH groups per mole of dimethylpolysiloxane vinyl group) 0.0 mol) and 0.1 part of a platinum compound (Pt concentration 1%) as a curing catalyst was blended to obtain a liquid composition.

  An axial core is placed in the center of the cylindrical mold, and this liquid composition is injected into the cylindrical mold from the injection port, cured by heating at 130 ° C. for 20 minutes, and further post-cured at 200 ° C. for 4 hours. A developing roller was obtained in the same manner as in Example 1 except that an elastic layer having a thickness of 2 mm was formed.

[Measurement of hardness and elastic modulus, characteristic image formation]
About the obtained elastic layer, the laminate of the elastic layer and the resin layer, the indenter indentation depth when a load of 100 mN / mm ² was applied and the amount of strain 30 minutes after releasing the load were the same as in Example 1. The elastic modulus of the resin layer was measured. Further, image formation was performed in the same manner as in Example 1, and the set trace image and the toner fused image were evaluated for the obtained image. The results are shown in Table 1.

[Example 6]
Primer treatment was performed on the surface of a SUM shaft core having a diameter of 6 mm and a length of 250 mm for the purpose of improving the adhesion to silicone rubber.

[Preparation of elastic layer]
100.0 parts of dimethylpolysiloxane (having vinyl groups at both ends of the molecular chain, weight average molecular weight 92,000), 5 parts of crystalline silica as filler, carbon black (Denka black, powdered product manufactured by Denki Kagaku Kogyo) ) 5 parts, organohydrogenpolysiloxane (having SiH groups at both molecular chain terminals and side chains, weight average molecular weight 910,000) 98.9 parts (one mole of dimethylpolysiloxane vinyl group contains SiH groups) An elastic layer was prepared in the same manner as in Example 1 except that a liquid composition containing 0.1 part of a platinum compound (Pt concentration 1%) was used as a curing catalyst. .

[Preparation of resin layer]
A resin layer was prepared in the same manner as in Example 1 except that the addition amount of urethane-modified polymeric MDI (Coronate 2520 manufactured by Nippon Polyurethane Industry Co., Ltd.) was 127 parts to obtain a developing roller.

[Measurement of hardness and elastic modulus, characteristic image formation]
A sheet was produced with the resin layer alone, and its elastic modulus E ′ was measured to be 9.9 × 10 ¹⁰ Pa. When the resin layer was peeled off by laser processing from the obtained developing roller and measured, it was 9.9 × 10 ¹⁰ Pa.

About the obtained elastic layer and the laminate of the resin layer and the elastic layer, the indenter indentation depth when a load of 100 mN / mm ² was applied in the same manner as in Example 1, and the distortion 30 minutes after releasing the load The amount was measured and the elastic modulus of the resin layer was measured. Further, image formation was performed in the same manner as in Example 1, and the set trace image and the toner fused image were evaluated for the obtained image. The results are shown in Table 1.

[Example 7]
[Preparation of developing roller]
As an elastic layer, 100.0 parts of dimethylpolysiloxane (having vinyl groups at both ends of the molecular chain, weight average molecular weight 6,100), 5 parts of crystalline silica as filler, carbon black (Denka Black manufactured by Denki Kagaku Kogyo) , Powdery product) 5 parts, organohydrogenpolysiloxane (having SiH groups at both ends and side chains of molecular chain, weight average molecular weight 62,000) 101.6 parts (based on 1 mol of vinyl group of dimethylpolysiloxane) Example 2 except that a liquid composition obtained by blending 0.1 part of a platinum compound (Pt concentration 1%) as a curing catalyst was used. In the same manner, a developing roller was obtained.

[Measurement of hardness and elastic modulus, characteristic image formation]
About the obtained elastic layer, the laminate of the elastic layer and the resin layer, the indenter indentation depth when a load of 100 mN / mm ² was applied and the amount of strain 30 minutes after releasing the load were the same as in Example 1. The elastic modulus of the resin layer was measured. Further, image formation was performed in the same manner as in Example 1, and the set trace image and the toner fused image were evaluated for the obtained image. The results are shown in Table 1.

[Example 8]
[Preparation of developing roller]
As an elastic layer, 100.0 parts of polypropylene glycol having a weight average molecular weight of 1,500, 5 parts of crystalline silica as a filler, 5 parts of carbon black (Denka black, powdered product manufactured by Denki Kagaku Kogyo), polypropylene of trimethylolpropane Example 2 except that a liquid composition obtained by adding a trifunctional triisocyanate obtained by reacting hexamethylene diisocyanate to a glycol adduct so that the NCO / OH value was 0.6 was used. In the same manner as above, a developing roller was obtained.

[Measurement of hardness and elastic modulus, characteristic image formation]
About the obtained elastic layer, the laminate of the elastic layer and the resin layer, the indenter indentation depth when a load of 100 mN / mm ² was applied and the amount of strain 30 minutes after releasing the load were the same as in Example 1. The elastic modulus of the resin layer was measured. Further, image formation was performed in the same manner as in Example 1, and the set trace image and the toner fused image were evaluated for the obtained image. The results are shown in Table 1.

[Example 9]
[Preparation of developing roller]
An elastic layer was formed in the same manner as in Example 3 except that a SUM shaft core having a diameter of 6 mm was used.

  MEK was added to 100 parts of polyimide (U varnish S manufactured by Ube Industries) and 4 parts of carbon black (MA-100 manufactured by Mitsubishi Chemical). After 5 hours of dispersion and rotation with a ball mill, 3 parts of urethane fine particles having an average particle size of 10 μm were added and the dispersion was rotated again for 1 hour. A film is formed by immersing the elastic layer in this solution, heat-treated at 140 ° C. for 4 hours, and further heat-treated at 250 ° C. for 3 hours to prepare a polyimide resin layer having a thickness of 20 μm. Thus, a developing roller was obtained.

[Measurement of hardness and elastic modulus, characteristic image formation]
A sheet was produced with the resin layer alone, and its elastic modulus E ′ was measured to be 6.7 × 10 ¹⁰ Pa. It was 6.6 × 10 ¹⁰ Pa when measured by peeling the resin layer from the obtained developing roller by laser processing.

About the obtained elastic layer and the laminate of the resin layer and the elastic layer, the indenter indentation depth when a load of 100 mN / mm ² was applied in the same manner as in Example 1, and the distortion 30 minutes after releasing the load The amount was measured and the elastic modulus of the resin layer was measured. Further, image formation was performed in the same manner as in Example 1, and the set trace image and the toner fused image were evaluated for the obtained image. The results are shown in Table 1.

[Comparative Example 1]
As a resin layer, it is obtained by adding MEK to 100 parts of acrylic polyol (Daicel Chemical Industries DC2016), 141 parts of urethane-modified polymeric MDI (Nihon Polyurethane Industry Coronate 2520) and 20 parts of carbon black (Mitsubishi Chemical MA-100). A developing roller was obtained in the same manner as in Example 3 except that the obtained liquid composition was used.

[Measurement of hardness and elastic modulus, characteristic image formation]
A sheet was prepared with the resin layer alone, and its elastic modulus E ′ was measured to be 3.8 × 10 ¹² Pa.

About the obtained elastic layer, the laminate of the elastic layer and the resin layer, the indenter indentation depth when a load of 100 mN / mm ² was applied and the amount of strain 30 minutes after releasing the load were the same as in Example 1. The elastic modulus of the resin layer was measured. Further, image formation was performed in the same manner as in Example 1, and the set trace image and the toner fused image were evaluated for the obtained image. The results are shown in Table 2.

[Comparative Example 2]
As a resin layer, 100 parts of polytetramethylene glycol (Hodogaya Chemical PTG1000SN) and 23 parts of an isocyanate compound (Millionate MT manufactured by Nippon Polyurethane Industry) were mixed stepwise in a MEK solvent. The mixture was reacted at 80 ° C. for 7 hours in a nitrogen atmosphere to obtain a polyurethane polyol having a weight average molecular weight Mw = 11000 and a hydroxyl value of 20.

  The liquid composition obtained by adding MEK to 100 parts of the obtained polyurethane polyol, 42 parts of urethane-modified polymeric MDI (Nihon Polyurethane Industry Coronate 2520) and 20 parts of carbon black (Mitsubishi Chemical MA-100) was used. A developing roller was obtained in the same manner as Example 3 except for the above.

[Measurement of hardness and elastic modulus, characteristic image formation]
A sheet was prepared with the resin layer alone, and its elastic modulus E ′ was measured to be 5.5 × 10 ⁷ Pa.

About the obtained elastic layer, the laminate of the elastic layer and the resin layer, the indenter indentation depth when a load of 100 mN / mm ² was applied and the amount of strain 30 minutes after releasing the load were the same as in Example 1. The elastic modulus of the resin layer was measured. Further, image formation was performed in the same manner as in Example 1, and the set trace image and the toner fused image were evaluated for the obtained image. The results are shown in Table 2.

[Comparative Example 3]
As an elastic layer, 100.0 parts of dimethylpolysiloxane (having vinyl groups at both ends of the molecular chain, weight average molecular weight 930,000), 12 parts of crystalline silica as a filler, carbon black (Denka Black manufactured by Denki Kagaku Kogyo) , Powdery product) 5 parts, organohydrogenpolysiloxane (having SiH groups at both molecular chain terminals and side chains, weight average molecular weight 88,000) 10.4 parts (based on 1 mol of vinyl group of dimethylpolysiloxane) In the same manner as in Example 2 except that a liquid composition to which 0.1 part of a platinum compound (Pt concentration 1%) was added was used as a curing catalyst. A developing roller was obtained.

[Measurement of hardness and elastic modulus, characteristic image formation]
About the obtained elastic layer, the laminate of the elastic layer and the resin layer, the indenter indentation depth when a load of 100 mN / mm ² was applied and the amount of strain 30 minutes after releasing the load were the same as in Example 1. The elastic modulus of the resin layer was measured. Further, image formation was performed in the same manner as in Example 1, and the set trace image and the toner fused image were evaluated for the obtained image. The results are shown in Table 2.

[Comparative Example 4]
As an elastic layer, 100.0 parts of dimethylpolysiloxane (having vinyl groups at both ends of the molecular chain and having a weight average molecular weight of 17,200), 12 parts of crystalline silica as a filler, carbon black (Denka made by Denki Kagaku Kogyo) Black, powdery product) 5 parts, organohydrogenpolysiloxane (having SiH groups at both molecular chain terminals and side chains, weight average molecular weight 300) 1.9 parts (1 mol of vinyl group of dimethylpolysiloxane) A developing roller was obtained in the same manner as in Example 3 except that a liquid composition to which 0.1 part of platinum compound (Pt concentration: 1%) was added as a curing catalyst was used. It was.

[Measurement of hardness and elastic modulus, characteristic image formation]
About the obtained elastic layer, the laminate of the elastic layer and the resin layer, the indenter indentation depth when a load of 100 mN / mm ² was applied and the amount of strain 30 minutes after releasing the load were the same as in Example 1. The elastic modulus of the resin layer was measured. Further, image formation was performed in the same manner as in Example 1, and the set trace image and the toner fused image were evaluated for the obtained image. The results are shown in Table 2.

It is a schematic sectional drawing which shows an example of the developing roller of this invention. It is a schematic perspective view which shows an example of the developing roller of this invention. 1 is a schematic configuration diagram illustrating an example of an image forming apparatus of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Charging roller 3 Laser beam 4 Pressure roller 5 Developing roller 6 Toner supply roller 7 Developing blade 8 Toner 9 Transfer roller 10 Cleaning blade 11 Waste toner container 12 Fixing roller 13 Recording material 14 Developer container 15 Shaft core 16 Elastic layer 17 Resin layer

Claims (8)

In a developing roller having a shaft core, an elastic layer sequentially provided on the shaft core, and a resin layer, the laminate of the elastic layer and the resin layer applies a load of 100 mN / mm ² by a universal hardness meter. The indentation depth rate when added is 4.0 to 10.0% of the thickness, and the strain rate 30 minutes after the load is released is 0.50% or less of the thickness, When the elastic layer is loaded with a load of 100 mN / mm ² by a universal hardness meter, the indenter depth is 10.0 to 50.0% of the thickness, and 30 minutes after the load is released. The strain ratio is 1.0 to 10.0% of the thickness, and the elastic modulus E ′ measured by a tensile method at a frequency of 10 Hz and a temperature of 20 ° C. is 10 ⁹ to 10 ¹¹ Pa. Developing roller to do. The elastic layer has a thickness of ² to 5 mm, and when the load of 100 mN / mm ² is applied by a universal hardness meter, the indenter push-in depth is 500 μm to 1000 μm, and 30 minutes after the load is released. Later strain is 50 μm to 200 μm, and the laminate of the elastic layer and the resin layer has an indenter indentation depth of 200 μm to 500 μm when a load of 100 mN / mm ² is applied by a universal hardness meter. The developing roller according to claim 1, wherein the strain after 30 minutes from the release of the toner is 10.0 μm or less.   The developing roller according to claim 1, wherein the elastic layer is formed of a silicone gel composition having a siloxane bond. The silicone gel composition comprises 100.0 parts by weight of an organopolysiloxane (A) having a molecular weight of 6,000 to 1,000,000 having at least two alkenyl groups in one molecule;
An organohydrogensiloxane (B) having a molecular weight of 500 to 1,000,000 having at least two hydrogen atoms bonded to silicon atoms in one molecule, and the total number of hydrogen atoms bonded to silicon atoms (b) With respect to the total number of alkenyl groups of siloxane (A) (a), parts by weight where b / a is 0.1 to 5.0,
The developing roller according to claim 3, comprising a platinum-based catalyst (C) in an amount sufficient for bonding with (A) and (B).   The developing roller according to any one of claims 1 to 4, wherein the resin layer contains one kind or two or more kinds selected from polyurethane resin, acrylic resin, and polyimide resin.   The method for producing a developing roller according to claim 3, wherein the silicone gel composition is cured by an addition reaction by heating.   An electrophotographic process cartridge having a developing roller that is detachably provided in an electrophotographic apparatus and supplies a developer formed in a thin film shape to a photosensitive member and develops an electrostatic latent image carried by the photosensitive member. An electrophotographic process cartridge, which is the developing roller according to claim 1.   An image forming apparatus having a photosensitive member carrying an electrostatic latent image and a developing roller for supplying the developer formed in a thin film to the photosensitive member and developing the electrostatic latent image carried by the photosensitive member. An image forming apparatus comprising the developing roller according to claim 1.

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