JP2007291298A - Elastic roller, method for producing the same, electrophotographic process cartridge and image-forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low cost elastic roller without having the unevenness of hardness/deformation recovery force in both of the axial direction and thickness direction of the elastic roller, a method for producing the roller, an electrophotographic process cartridge and an image-forming device. <P>SOLUTION: This elastic roller is provided with that an elastic layer consisting of a silicone rubber composition containing an inorganic filler and formed around its axial core body satisfies the following conditions A to C. The condition A: The blended amount of the inorganic filler is ≥5 and ≤35 pts.mass based on 100 pts.mass silicone rubber. The condition B: The composition of the inorganic filler is ≥10 and ≤50 mass% particles having silicon atom and ≥50 and ≤90 mass% carbon black having ≥10 and ≤40 nm mean primary particle diameter. The condition C: In the particles containing the silicon atom, their ≥5 and ≤25 mass% are silica having ≥7 and ≤40 nm mean primary particle diameter. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an elastic roller used in an image forming apparatus such as a printer and a copying machine, and a manufacturing method thereof, and further relates to an electrophotographic process cartridge and an image forming apparatus using the elastic roller as a developing roller.

  A conventional electrophotographic image forming apparatus will be described below.

  An image forming unit is installed in the main body of the apparatus, and an image is output through processes of cleaning, charging, latent image, development, transfer, and fixing.

  The image forming unit includes a photosensitive drum as an image carrier, and a cleaning unit, a charging unit, a latent image forming unit, a developing unit, and a transfer unit are provided around the photosensitive drum. The developer image on the photosensitive drum formed by the image forming unit is transferred to the recording material by the transfer unit, conveyed to the fixing unit, heated and pressed by the fixing unit, fixed to the recording material, and recorded as a recorded image. Discharged.

  In a printer using an electrophotographic system, a photosensitive drum is uniformly charged by a charging roller, and an electrostatic latent image is formed on the surface by a laser or the like on which image information is placed. With respect to the electrostatic latent image, the developer carried on the developing roller uniformly with an appropriate charge by the developer applying roller and the developer regulating member in the developing container is transferred at the contact portion between the photosensitive drum and the developing roller ( Development) is performed. Thereafter, the developer image on the photosensitive drum is transferred onto the recording paper by the action of the transfer roller at the transfer portion. The recording paper carrying the developer image is conveyed to a fixing unit and fixed by heat and pressure (pressure roller and fixing roller). On the other hand, the developer remaining on the photosensitive drum is removed by a cleaning blade, and a series of processes is completed.

  In this apparatus, the developing roller is in pressure contact with the photosensitive drum and the developer regulating member, and when the use is started, the developer is interposed between the developing roller and the photosensitive drum and between the developing roller and the developer regulating member. is doing. The developer remaining on the developing roller without being transferred to the photosensitive drum is peeled off by the developer applying roller in contact with the developing roller and returned to the developing container. The developer returned from the developing roller is stirred in the container and conveyed again onto the developing roller by the developer application roller. As these steps are repeated, the developer is under great stress. Therefore, in order to reduce stress on the developer, the developing roller is formed of a material made of an elastic body having a low hardness.

  Further, when the elastic roller is a developing roller or a charging roller, it always rotates in contact with other members, so that the contact state must be kept stable. That is, since the developing roller and the charging roller are in pressure contact with other members with a predetermined contact width, it is desirable that the developing roller and the charging roller be easily deformed and at the same time have excellent deformation recovery force. If the contact state cannot be kept stable, the supply amount of the developer varies or the charged state becomes uneven, which adversely affects the image.

  The developing roller used in such a contact developing system is an elastic roller having a configuration in which an elastic layer is provided on the outer periphery of the shaft core. Furthermore, there is an elastic roller provided with a surface layer by applying various resin solutions on the elastic layer as needed to adapt the surface characteristics to the purpose of use.

  In recent years, there is an increasing need for colorization and high image quality of electrophotography, and elastic rollers used in electrophotographic apparatuses are required to have higher contact stability. For example, in the contact development system, the developing roller is always in contact with the photosensitive drum surface. For this reason, if the contact width is not accurate, the nip width and nip force between the photosensitive drum and the developing roller vary. As a result, image defects such as density unevenness occur. In addition, when the deformation recovery force is small, a pressure contact mark is generated, which also causes an image defect.

  In other words, it is important that the elastic roller used in the electrophotographic image forming apparatus has an appropriate elastic layer with low hardness and a large deformation recovery force. Further, it is necessary that the hardness and deformation recovery force have little variation even in the axial direction and the thickness direction of the elastic roller.

  From such a viewpoint, silicone rubber is used as the elastic material of the elastic layer. Silicone rubber includes an addition reaction crosslinking type, a condensation reaction crosslinking type, and a peroxide crosslinking reaction type, and particularly has good processability and high dimensional accuracy stability, and no reaction by-products are generated during the curing reaction. For reasons of excellent productivity, addition reaction cross-linkable liquid silicone rubber is used.

  For example, a charging roller is disclosed in which the elastic layer is silicone rubber, the roller hardness is 35 or less in Asker C, and the compression set is 3% or less (see, for example, Patent Document 1). According to this, it is possible to prevent charging failure of the member to be charged over a long period of time.

  Also, an elastic roller is disclosed in which the elastic layer is composed of two layers, and the outer layer of which is silicone rubber (see, for example, Patent Document 2). According to this, there is an advantage that the processability is good and the dimensional accuracy can be further improved by using silicone rubber as the outer layer.

  However, regarding these elastic rollers, variations in hardness and deformation recovery force with respect to the axial direction and the thickness direction of the elastic roller, which affect the colorization and high image quality of electrophotography, have not been studied. These elastic rollers are usually manufactured by a method using a mold. As a result, an increase in the cost of production equipment is unavoidable, resulting in a costly elastic roller.

  While satisfying the performance characteristics described above, it is also required to reduce the cost by the elastic roller manufacturing method.

  Conventionally, in order to manufacture an elastic roller, a molding method using a mold is often used. For example, there is a mold forming technique in which one or a plurality of reservoir grooves are provided in the shaft core receiving portion (see, for example, Patent Document 3). According to this, it is said that good molding can be performed without reducing the dimensional accuracy of the elastic roller by allowing excess elastic layer material to escape into the reservoir groove. As described above, a molding method using a mold is generally used to mold a highly accurate elastic roller. However, in the mold forming technology, a large number of highly accurate molds are required, and it is inevitable that the production equipment will be expensive.

  In addition, as a method for forming the elastic layer material on the outer periphery of the shaft core body without using a mold, for example, coating is performed by a spray coating method, a dip coating method, a roll coating method, a blade coating method, or an annular coating tank. Various methods such as a coating method using a ring-shaped coating head have been studied.

  An elastic layer having a desired function is formed on the outer periphery of the shaft core body in accordance with various uses of the elastic roller. Particularly in recent years, in order to express such a desired function, an elastic layer from a uniform thin layer to a thickness of about several millimeters is required, and the elastic layer material itself to be applied is diversified. Along with this, some elastic layer materials are changed from a low viscosity to a high viscosity. Therefore, in the conventional coating method, it has become impossible to cover the coating range of such an elastic layer material.

  For example, the spray coating method can use only an elastic layer material having a low viscosity. If the viscosity of the elastic layer material is high, atomization of the elastic layer material becomes difficult.

  In the blade coating method and the roll coating method, for example, a blade or a roll is disposed in the axial direction of a coated shaft core body, and the elastic layer material is coated with the blade or the roll while rotating the shaft core body. After rotating the shaft core by one to several turns, the blade or roll is moved backward to finish the coating. At the end of this coating, when the blade or roll is retracted and separated from the uncured and undried elastic layer material, the elastic layer material has a viscosity that is thicker than the other parts due to the viscosity of the elastic layer material. Part or thin part occurs. In particular, when the viscosity of the elastic layer material is high, the portion where the thickness is problematic cannot be recovered by the leveling of the elastic layer thereafter, and a uniform elastic layer cannot be obtained.

  In the dip coating method, the problem of non-uniformity of the elastic layer in the spray coating method, blade coating method, roll coating method and the like is improved. However, since the control of the thickness of the elastic layer is governed by the physical properties of the elastic layer material, such as the viscosity, surface tension and density, and other temperatures of the elastic layer material, the physical properties of the elastic layer material may be kept constant at all times. Necessary, but difficult to keep constant. Further, when the elastic layer material has a high viscosity, a thin layer cannot be applied. For this reason, in the spray coating method, blade coating method, roll coating method and dip coating method, a highly viscous elastic layer material is diluted with a solvent, and the elastic layer material is lowered to a viscosity necessary for coating. After coating, the solvent used to dilute the elastic layer material could be removed by, for example, evaporation to form an elastic layer.

  As a method of directly applying a high-viscosity elastic layer material, a method of coating in an annular coating tank is known (for example, see Patent Document 4). This coating method includes an annular coating tank that holds an elastic layer material and has an annular sealing material having a hole smaller than the outer diameter of the shaft core body at the bottom, and the shaft core body is placed in the hole of the annular sealing material. Through this, the shaft core body is relatively raised from the annular coating tank, and the elastic layer material is applied to the surface of the shaft core body. In this method, coating is possible within a certain viscosity range. Compared with the dip coating method, the dip time does not take, so the production speed is increased, coating is possible with a small amount of elastic layer material, and the shaft core is continuously supplied to the annular coating tank. Therefore, there is an advantage that continuous coating is possible. However, in such a coating method in the annular coating tank, the shaft core body to be coated is in contact with the annular sealing material that is a part of the annular coating tank. The shaft core may be damaged during the construction process.

  Further, as a method for directly applying a high-viscosity elastic layer material to a shaft core, there is a coating method using a ring-shaped coating head (see, for example, Patent Document 5). According to this, the restriction of the coating process due to the viscosity of the elastic layer material and the thickness of the elastic layer is removed, and the elastic layer material is directly applied on the outer periphery of the shaft core body with a simpler device, so that the good and uniform A flexible elastic layer can be formed. In this method, the elastic layer material is applied to the surface of the shaft core body in a state where the center line of the shaft core body is parallel to the horizontal direction. That is, a step of preparing a ring-shaped coating head having an inner diameter substantially equal to the outer diameter of the shaft core body after coating the elastic layer material on the surface of the shaft core body, the shaft core body on the inner side of the coating head A step of arranging the coating head on the same axis, a step of supplying an elastic layer material to a gap between the inner peripheral surface of the coating head and the shaft core, and an axis line of the coating head with respect to the shaft core in the axial direction of the shaft core Coating method having a process of moving relative to the same axis.

  In this coating method, an elastic layer material is supplied to the gap between the inner peripheral surface of the coating head and the shaft core, and the coating head is coaxial with the axis in the axial direction of the shaft core with the shaft core in a horizontal state. The elastic layer material is applied to the outer peripheral surface of the shaft core body by relatively moving them. Since the coating head has a ring shape with an inner diameter approximately equal to the outer diameter of the part where the coating layer is formed on the shaft core body, the coating head is in a non-contact state with respect to the shaft core body. No trace of coating remains. Further, since the shaft core body is in a horizontal state, dripping of the elastic layer material due to gravity can be reduced. In particular, it is possible to eliminate the dripping of the elastic layer material at the start and immediately after the application, and to eliminate the influence on the necessary part of the application.

As described above, when variations in hardness and deformation recovery force occur in the axial direction and thickness direction of the elastic roller, the nip width and nip force vary with respect to the contacted member. As a result, an image defect occurs. In addition, the use of a mold in the elastic roller manufacturing method increases the cost.
JP 09-244348 A JP 2000-283146 A JP 2000-006163 A JP 2004-275824 A JP 2003-190870 A

  Accordingly, an object of the present invention is to provide a low-cost elastic roller having no variation in hardness and deformation recovery force in the axial direction and thickness direction of the elastic roller, a method for manufacturing the elastic roller, an electrophotographic process cartridge, and an image forming apparatus. It is to provide.

  As a result of intensive studies to solve the above problems, the present inventors have reduced the variation in hardness and deformation recovery force with respect to the axial direction and thickness direction of the elastic roller by prescribing the silicone rubber composition. It has been found that the variation in hardness and deformation recovery force in a minute region is manifested by the variation in the crosslink density of the silicone rubber composition, and the present invention has been further studied.

  That is, the present invention is characterized by having the following configuration.

(1) An elastic roller characterized in that an elastic layer made of a silicone rubber composition containing an inorganic filler is formed around a shaft core, and the elastic layer satisfies the following conditions A to C.
Condition A: The compounding amount of the inorganic filler is 5 parts by mass or more and 35 parts by mass or less with respect to 100 parts by mass of the silicone rubber.
Condition B: The composition of the inorganic filler is 10% by mass to 50% by mass of particles having silicon atoms and 90% by mass to 50% by mass of carbon black having an average primary particle size of 10 nm to 40 nm.
Condition C: The silica having an average primary particle size of 7 nm or more and 40 nm or less is 5% by mass or more and 25% by mass or less of the particles having silicon atoms.

(2) When the cross-linking density in the region from the surface of the elastic roller to a depth of 500 μm is ν ₁ and the cross-linking density in the region from the surface of the elastic roller is 500 μm to 1000 μm is ν ₂ , ν ₁ / ν ₂ The elastic roller according to the above (1), wherein is 0.80 or more and 1.20 or less.

(3) The elastic roller according to (2) above, wherein the crosslink density ν ₁ and ν _{2 of the} elastic roller are both 5 × 10 ⁻⁵ mol / cc or more and 5 × 10 ⁻⁴ mol / cc or less.

(4) In the axial direction of the elastic roller, when the cross-linking density in the region from one end to 10 mm is ν ₃ , and the cross-linking density in the region 10 mm from the one end opposite to the one end is ν ₄ , ν ₃ / ν ₄ is 0.80 or more and 1.25 or less, The elastic roller of said (1) characterized by the above-mentioned.

(5) The elastic roller according to (4), wherein the crosslink density ν ₃ and ν _{4 of the} elastic roller are both 5 × 10 ⁻⁵ mol / cc or more and 5 × 10 ⁻⁴ mol / cc or less.

(6) A method for producing an elastic roller in which an elastic layer made of a silicone rubber composition containing an inorganic filler is formed around a shaft core, and the elastic layer satisfies the following conditions A to C, and includes at least the following steps A method for producing an elastic roller comprising the steps (a) to (c).
Condition A: The compounding amount of the inorganic filler is 5 parts by mass or more and 35 parts by mass or less with respect to 100 parts by mass of the silicone rubber.
Condition B: The composition of the inorganic filler is 10% by mass to 50% by mass of particles having silicon atoms and 90% by mass to 50% by mass of carbon black having an average primary particle size of 10 nm to 40 nm.
Condition C: The silica having an average primary particle size of 7 nm or more and 40 nm or less is 5% by mass or more and 25% by mass or less of the particles having silicon atoms.
Process a: A ring-type coating head is arranged so as to be concentric with the shaft core.
Step A: The shaft core is moved in the axial direction relative to the coating head, and an elastic layer material made of a silicone rubber composition is applied from the coating head onto the outer periphery of the shaft core during the movement.
Process c: The elastic layer material applied on the shaft core is cured by infrared heating.

(7) When the crosslink density in the region from the surface of the elastic roller to a depth of 500 μm is ν ₁ and the crosslink density in the region from the surface of the elastic roller to a depth of 500 μm to 1000 μm is ν ₂ , ν ₁ / ν ₂ Is 0.80 or more and 1.20 or less, the method for producing an elastic roller according to (6) above.

(8) The production of the elastic roller according to (7) above, wherein the crosslink density ν ₁ and ν _{2 of the} elastic roller are both 5 × 10 ⁻⁵ mol / cc or more and 5 × 10 ⁻⁴ mol / cc or less. Method.

(9) in the axial direction of the elastic roller, ₃ a cross-link density in the region from one end portion to 10mm [nu, when the ₄ the crosslink density of 10mm regions [nu from one end portion opposite to the該片end, [nu ₃ / [nu ₄ is 0.80 or more and 1.25 or less, The manufacturing method of the elastic roller of said (6) characterized by the above-mentioned.

(10) The elastic roller according to (9) above, wherein the crosslink density ν ₃ and ν _{4 of the} elastic roller are both 5 × 10 ⁻⁵ mol / cc or more and 5 × 10 ⁻⁴ mol / cc or less. Method.

(11) An elastic roller manufactured by the manufacturing method according to any one of (6) to (10) above.

(12) The elastic roller according to any one of (1) to (5) and (11), wherein the elastic roller is a developing roller.

(13) An electrophotographic process cartridge in which the elastic roller of (12) is incorporated as a developing roller.

(14) An image forming apparatus in which the elastic roller of (12) is incorporated as a developing roller.

  According to the present invention, a low-cost elastic roller having no variation in hardness and deformation recovery force in the axial direction and thickness direction can be provided at low cost. Moreover, the elastic roller manufacturing method of the present invention can provide an elastic roller with good performance. Furthermore, the elastic roller of the present invention is useful as a developing roller for an electrophotographic apparatus, and an electrophotographic process cartridge and an image forming apparatus incorporating the developing roller exhibit extremely excellent image characteristics.

  Hereinafter, the present invention will be described in detail.

  FIG. 1 is a perspective view of an example of an elastic roller according to the present invention.

  In FIG. 1, reference numeral 101 denotes a shaft core, and the elastic roller according to the present invention is provided with an elastic layer 102 made of a silicone rubber composition containing an inorganic filler around the shaft core 101.

  The shaft core 101 functions as an electrode and a support member of the elastic roller 1. The shaft core 101 is made of, for example, a metal or alloy such as aluminum, copper alloy, or stainless steel, iron plated with chromium, nickel, or the like, or synthetic resin. The shape is preferably a columnar shape or a cylindrical shape with a hollow center. The outer diameter of the shaft core can be determined as appropriate, but it is usually appropriate to be in the range of 4 mm to 20 mm.

In the present invention, the elastic layer made of the silicone rubber composition containing the inorganic filler formed around the shaft core body 101 needs to satisfy the following conditions A to C.
Condition A: The inorganic filler is 5 parts by mass or more and 35 parts by mass or less with respect to 100 parts by mass of the silicone rubber.
Condition B: The composition of the inorganic filler is 10% by mass to 50% by mass of particles having silicon atoms and 90% by mass or less and 50% by mass or more of carbon black having an average primary particle size of 10 nm to 40 nm.
Condition C: Among the particles having silicon atoms, 5 to 25% by mass is silica having an average primary particle diameter of 7 nm or more and 40 nm or less.

  As the base material of the elastic layer, silicone rubber is used because it is desired to have a moderately low hardness and good deformation recovery force. Silicone rubber includes addition reaction cross-linking type, condensation reaction cross-linking type, and peroxide curing type, which can be appropriately selected and used, but has good processability and high dimensional accuracy stability. An addition reaction cross-linkable liquid silicone rubber is preferred because of excellent productivity such as no generation of reaction by-products.

  The addition reaction type liquid silicone rubber is composed of an organopolysiloxane having an alkenyl group (main agent) and an organohydrogenpolysiloxane (curing agent), and further contains a catalyst and other additives as appropriate.

  The organopolysiloxane having an alkenyl group is a base polymer of a silicone rubber raw material, and the molecular weight thereof is not particularly limited, but the weight average molecular weight (Mw) is preferably 10,000 to 1,000,000, preferably 50,000 to 700,000. The following is more preferable.

  The alkenyl group of this organopolysiloxane is a site that reacts with the active hydrogen of the organohydrogenpolysiloxane to form a crosslinking point, and the type thereof is not particularly limited, but for reasons such as high reaction with active hydrogen, It is preferably at least one of a vinyl group and an allyl group, and more preferably a vinyl group.

  The organohydrogenpolysiloxane functions as a crosslinking agent for addition reaction in the curing process, and two or more silicon-bonded hydrogen atoms in one molecule are required. It is preferable that there are more than one. The molecular weight of the organohydrogenpolysiloxane is not particularly limited, and a preferable weight average molecular weight (Mw) is suitably 1000 or more and 10,000 or less. In order to suitably perform the curing reaction, a polymer having a relatively low molecular weight and a weight average molecular weight of 1,000 to 5,000 is preferred.

  The addition reaction type liquid silicone rubber preferably contains a known platinum-based catalyst as a crosslinking catalyst. Examples of the platinum-based catalyst include platinum alone, platinum compounds, chloroplatinic acid, alcohol compounds of chloroplatinic acid, ether compounds, and complexes with hydrates. Moreover, the transition metal compound which shows a catalytic action in hydrosilylation reaction can also be used as a crosslinking catalyst. The addition amount of the crosslinking catalyst is preferably in the range of 1 ppm to 2000 ppm as platinum atoms or transition metal atoms with respect to the organopolysiloxane.

  An inorganic filler is blended with the silicone rubber to form a silicone rubber composition for the elastic layer. The inorganic filler is blended in an amount of 5 parts by weight to 35 parts by weight with respect to 100 parts by weight of the silicone rubber. If the amount is less than 5 parts by mass, the aggregation effect due to the inorganic filler is small, the viscosity of the silicone rubber composition is low, the inorganic filler tends to be unevenly distributed, the crosslink density varies, and the hardness is harder in the axial direction and thickness direction of the elastic roller.・ Variation of deformation recovery force increases. In addition, the viscosity of the silicone rubber composition cannot be increased, and the formulation is not compatible with a low-cost manufacturing method for an elastic roller. On the other hand, when the amount is more than 35 parts by mass, the elastic layer has high hardness, and the deformation recovery force becomes small.

  It is important that the inorganic filler blended in the silicone rubber is mainly carbon atom-containing particles and carbon black having an average primary particle size of 10 nm to 40 nm. And the composition is 10 mass% or more and 50 mass% or less of particles which have a silicon atom in all the inorganic fillers, and carbon black is 90 mass% or less and 50 mass% or more.

  When the number of silicon atom-containing particles is less than 10% by mass, the reinforcing effect of the silicon atom-containing particles is small, and the variation in hardness and deformation recovery force increases in the axial direction and thickness direction of the elastic roller. If the number of silicon atom-containing particles is more than 50% by mass, uniform dispersion in silicone rubber becomes difficult.

  On the other hand, when the amount of carbon black is more than 90% by mass, the elastic layer has a high hardness and the deformation recovery force becomes small. When the amount of carbon black is less than 50% by mass, the viscosity of the silicone rubber composition is low, the inorganic filler is likely to be unevenly distributed, the crosslink density varies, and the hardness and deformation are recovered in the axial direction and thickness direction of the elastic roller. The variation in force increases. In addition, the viscosity of the silicone rubber composition cannot be increased, and the formulation is not compatible with a low-cost manufacturing method for an elastic roller.

  The carbon black that can be used here may be any carbon black as long as the average primary particle size is 10 nm or more and 40 nm or less. Examples of such carbon black include SAF, ISAF, HAF, MAF, FEF, GPF, SRF, FT, and MT, and further include general-purpose materials such as acid carbon subjected to oxidation treatment and pyrolytic carbon. . If the average primary particle size is carbon black smaller than 10 nm, the carbon black itself has high cohesiveness and it becomes difficult to uniformly disperse it in the silicone rubber. Thereby, the dispersion | variation in hardness and a deformation | transformation recovery force becomes large with respect to the axial direction and thickness direction of an elastic roller. On the other hand, when the average primary particle size is larger than 40 nm, the cohesiveness of the carbon black itself is weak, the silicone rubber composition has a low viscosity, the workability is lowered, and the production efficiency is deteriorated.

  Examples of the particles having a silicon atom include dry silica, wet silica, diatomaceous earth, quartz powder, aluminosilicate, and the like. If the number of silicon atom-containing particles in the inorganic filler is less than 10% by mass, the reinforcing effect of the silicon atom-containing particles is small, and the hardness / deformation recovery force varies in the axial direction and thickness direction of the elastic roller. growing. On the other hand, when the amount is more than 50% by mass, uniform dispersion in the silicone rubber becomes difficult.

  Further, it is important that the component having 5% by mass or more and 25% by mass or less in the particles having silicon atoms is silica having an average primary particle size of 7 nm or more and 40 nm or less (hereinafter simply referred to as “silica”). When silica is a component less than 5% by mass in the particles having silicon atoms, the reinforcing effect is not exhibited, and the dimensional accuracy stability is lowered during the production of the elastic roller. Further, when silica is a component of more than 25% by mass in the particles having silicon atoms, the elastic layer has a high hardness and the deformation recovery force becomes small.

  As the silica, a so-called dry method produced by vapor phase oxidation of a silicon halide or dry silica called fumed silica can be preferably used. Also, so-called wet silica produced from water glass can be used. Furthermore, the surface of these silicas may be chemically treated.

  In the present invention, it is important that silica has an average primary particle size of 7 nm or more and 40 nm or less. When the average primary particle size is smaller than 7 nm, the cohesiveness of the silica itself is strong, and uniform dispersion in the silicone rubber becomes difficult. On the other hand, when the average primary particle size is larger than 40 nm, the cohesiveness of silica itself is weak, the silicone rubber composition has a low viscosity, the workability is lowered, and the production efficiency is poor.

  The silicone rubber composition forming the elastic layer has a non-conductive filler such as calcium carbonate, polydimethylsiloxane oil, diphenylsilanediol, trimethylsilanol, and phthalic acid derivative so that the desired performance can be obtained. Various additives such as a plasticizer such as an adipic acid derivative, a heat resistance agent, a flame retardant, an antioxidant, a crosslinking accelerator, a crosslinking retarder, and a crosslinking aid may be appropriately blended.

  Furthermore, in this invention, in order to adjust the electroconductivity of an elastic layer, a conductive agent can be selected suitably and can be added. The carbon black partially functions as a conductive agent. In addition to the carbon black shown above, a carbon-based conductive agent such as conductive carbon black and graphite, an electronic conduction mechanism such as metal powder, conductive metal oxide, etc. It is also possible to use a conductive agent having an ion conductive mechanism such as an alkali metal salt or a quaternary ammonium salt.

  By using the silicone rubber composition, it is possible to reduce variations in hardness and deformation recovery force with respect to the axial direction and thickness direction of the elastic roller. Moreover, the variation in the crosslinking density of the silicone rubber composition can be reduced, and the variation in the hardness and deformation recovery force in a minute region can be reduced.

The crosslink density of the elastic layer of the elastic roller of the present invention is shown in FIG. 2, that is, the region 102 a from the surface of the elastic roller to a depth of 500 μm, the region 102 b from the surface of the elastic roller to a depth of 500 μm to 1000 μm, In each of the 10 mm regions 102c and 102d at both ends of the elastic layer, the measurement is performed as described later. The crosslink density at this time is represented by ν _{1 in} the region 102 a from the surface of the elastic roller to a depth of 500 μm, ν _{2 in} the region 102 b from the surface of the elastic roller by 500 μm to 1000 μm, and from one end of the elastic roller. A region 102c up to 10 mm is denoted by ν ₃ , and a region 102d 10 mm from one end opposite to the one end is denoted by ν ₄ . In addition, 101 is an axial core body and 102 is an elastic layer.

Here, it is preferable that the variation in the crosslink density in the thickness direction of the elastic layer is 0.80 or more and 1.20 or less in ν ₁ / ν ₂ . When ν ₁ / ν ₂ is within this range, the nip width and nip force between the elastic roller and the contacted member become uniform, and image defects (density unevenness) do not occur. Moreover, it is desirable that the variation in the crosslink density in the axial direction of the elastic layer is 0.80 or more and 1.25 or less in ν ₃ / ν ₄ . When ν ₃ / ν ₄ is within this range, the elastic roller and the contacted member can achieve a uniform contact width on the left and right, and image defects (density unevenness) do not occur.

Moreover, it is desirable that the crosslink densities ν ₁ , ν ₂ , ν ₃ and ν ₄ of the elastic roller described above are all 5 × 10 ⁻⁵ mol / cc or more and 5 × 10 ⁻⁴ mol / cc or less. If the crosslink density is less than 5 × 10 ⁻⁵ mol / cc, the elastic layer of the elastic roller is too low in hardness, and the contact state cannot be kept stable, and pressure distribution to the contacted member may occur. On the other hand, if it is greater than 5 × 10 ⁻⁴ mol / cc, the elastic layer of the elastic roller may have a high hardness and the deformation recovery force may be reduced.

  The elastic roller of the present invention is not limited in its manufacturing method as long as the elastic layer having the above-described configuration is formed on the shaft body, but the silicone rubber composition for the elastic layer is formed concentrically on the shaft body. The silicone rubber composition is then preferably heated and cured.

  As a method for forming the silicone rubber composition for the elastic layer on such a shaft core, there is a coating method using a ring-type coating head, which is a preferred method in the present invention.

That is, the elastic roller manufacturing method of the present invention includes at least the following steps a, i and c.
Process a: A ring-type coating head is arranged so as to be concentric with the shaft core.
Step A: The shaft core is moved in the axial direction relative to the coating head, and an elastic layer material made of a silicone rubber composition is applied from the coating head onto the outer periphery of the shaft core during the movement.
Process c: The elastic layer material applied on the shaft core is cured by infrared heating.

  FIG. 3 shows a schematic explanatory diagram of a ring coater having a ring-type coating head that can be suitably used in the method for producing an elastic roller of the present invention.

  In this ring coat machine, a column 32 is attached substantially vertically on a gantry 31, and a precision ball screw 33 is attached substantially vertically on the gantry 31 and the column 32. Reference numeral 44 denotes a linear guide, and two linear guides 44 are attached to the column 32 in parallel with the precision ball screw 33.

  The LM guide 34 connects the linear guide 44 and the precision ball screw 33, and a rotary motion is transmitted from the servo motor 35 via the pulley 36 so that the LM guide 34 can be raised and lowered. A ring-shaped coating head 38 for applying an uncured product of the silicone rubber composition onto the outer periphery of the shaft core body 101 is attached to the column 32.

  Further, a bracket 37 is attached to the LM guide 34, and a shaft core lower holding shaft 39 for holding and fixing the shaft core body 101 is attached to the bracket 37 substantially vertically. The central axis of the shaft core upper holding shaft 40 that holds the shaft core body 101 of the roller on the opposite side is attached to the upper portion of the bracket 37, and the shaft core upper holding shaft 40 faces the shaft core lower holding shaft 39. And it arrange | positions so that it may become substantially concentric, and the shaft core body is hold | maintained.

  The center axis of the ring-shaped coating head 38 is supported so as to be parallel to the moving direction of the shaft core lower holding shaft 39 and the shaft core upper holding shaft 40. Further, when the shaft core lower holding shaft 39 and the shaft core upper holding shaft 40 are moved up and down, the central axis of the discharge port which is an annular slit opened inside the coating head 38 and the shaft core lower holding shaft 39 are arranged. In addition, the central axis of the shaft core holding shaft 40 is adjusted so as to be substantially concentric.

  With such a configuration, the central axis of the discharge port formed in the annular slit of the coating head 38 can be aligned substantially concentrically with the central axis of the shaft core 101, and the inner peripheral surface of the ring-shaped coating head and the above-mentioned A uniform gap is formed between the outer peripheral surface of the shaft core body 101.

  A supply port 41 for the liquid silicone rubber composition is connected to a supply valve 43 via a pipe 42. The material supply valve 43 includes a mixing mixer, a material supply pump, a material fixed amount discharge device, a material tank, and the like in front of the material supply valve 43, and can discharge a fixed amount (a constant amount per unit time) of liquid rubber. A predetermined amount of the silicone rubber composition is weighed from the material tank by a material dispensing device and mixed by a mixing mixer. Thereafter, the silicone rubber composition mixed by the material supply pump is sent from the material supply valve 43 to the supply port 41 via the pipe 42.

  The silicone rubber composition fed from the supply port 41 passes through the flow path in the ring type coating head 38 and is discharged from the nozzle of the ring type coating head 38. In order to make the thickness of the silicone rubber composition constant, the discharge amount from the ring-shaped coating head nozzle and the supply amount from the material supply pump are made constant, and the shaft core body 101 held in the vertical direction (axis The shaft core body 101 moves in the axial direction relative to the coating head 38 by being moved upward in the direction of the central axis of the core body, and is made of a silicone rubber composition on the outer periphery of the shaft core body 101. An uncured layer 102 having a cylindrical shape (roll shape) is formed. At this time, the clearance between the shaft core 101 and the ring-type coating head nozzle is preferably set to a clearance equal to or larger than the desired thickness of the elastic layer because the silicone rubber composition shrinks due to curing. In particular, the clearance is preferably about 1.1 times the layer thickness. The thickness of the elastic layer is usually preferably in the range of 2 mm to 10 mm.

  As disclosed in Patent Document 5, there is a ring coater in which a ring-type coating head is moved in the horizontal direction (horizontal type), and the uniformity of the coating layer (elastic layer) is sufficient. It can be obtained. However, when the thickness of the coating layer (elastic layer) is 2.0 mm or less, it is also useful in a horizontal ring coater. However, in the elastic roller used in the electrophotographic image forming apparatus as in the present invention, the thickness of the elastic layer is generally 2.0 mm or more. If a horizontal ring coater is applied so that the coating layer is 2.0 mm or more, drooping occurs in the direction of gravity due to the weight of the coating layer, resulting in variations in the thickness, hardness, and deformation recovery force of the elastic layer. It will be considered to be larger. Therefore, in the present invention, the vertical ring coater as described above is preferable.

  In the next step, the layer of the uncured silicone rubber composition is heat-treated by infrared heating and cured to obtain an elastic roller. The surface of the uncured silicone rubber composition has adhesiveness. For this reason, the heat treatment is preferably a non-contact, simple apparatus, and infrared heating that can uniformly heat the uncured layer of the silicone rubber composition in the longitudinal direction. At this time, the infrared heating device is fixed, and the shaft core body provided with the cylindrical (roll-shaped) uncured material layer made of the silicone rubber composition is rotated in the circumferential direction, so that the heat treatment is uniformly performed in the circumferential direction. Is called. The heat treatment temperature of the surface of the elastic layer material of the silicone rubber composition is preferably from 100 ° C. to 250 ° C. at which the curing reaction starts, although it depends on the silicone rubber composition to be used.

  Here, for the purpose of stabilizing physical properties after curing of the elastic layer, removing reaction residues and unreacted low molecular components in the elastic layer, the elastic layer after infrared heating is further subjected to secondary curing such as heat treatment. Also good. Thereafter, both ends of the elastic layer are pierced to make the elastic layer as long as necessary, and abnormalities are likely to occur during the formation of the elastic layer, and the starting end and the terminal end when the silicone rubber composition is formed on the shaft core are previously set. It is also preferable to remove.

  A surface layer can be further provided on the outer peripheral side of the elastic layer formed as described above from the viewpoints of wear resistance, toner chargeability and releasability. Examples of the material for forming the surface layer include various polyamides, fluororesins, hydrogenated styrene-butylene resins, urethane resins, silicone resins, polyester resins, phenol resins, imide resins, olefin resins, and the like. These materials may be used alone or in combination of two or more. Various additives are added to these materials as necessary.

  These materials constituting the surface layer can be dispersed using a conventionally known dispersion apparatus using beads such as a sand mill, a paint shaker, a dyno mill, and a ball mill. The obtained coating material for forming the surface layer can be applied to the surface of the elastic layer by spray coating, dipping or the like. The thickness of the surface layer is preferably 5 μm or more and 50 μm or less. 5 μm or more is preferable from the viewpoint of preventing the low molecular weight component from seeping out and contaminating the photosensitive drum, and 50 μm or less is preferable from the viewpoint of preventing the roller from becoming hard and causing fusion. More preferably, they are 10 micrometers or more and 30 micrometers or less.

  The elastic roller of the present invention can be used as a developing roller. The developing roller carries a developer (toner) in a state of being in contact with or pressed against a photosensitive drum as a latent image carrier that carries a latent image. The developing roller has a function of visualizing the latent image as a toner image by applying toner as a developer to the photosensitive drum. Further, the electrophotographic process cartridge and the image forming apparatus of the present invention use the elastic roller of the present invention as the developing roller.

  An example of an electrophotographic process cartridge and an image forming apparatus in which the elastic roller of the present invention is mounted as a developing roller is schematically shown in FIG. This will be described below with reference to FIG.

  The image forming apparatus includes four image forming units 10a to 10d for forming yellow, cyan, magenta, and black images, respectively, and is provided in a tandem manner. The specifications of the photosensitive drum 11, the charging device 12 (charging roller in the drawing), the image exposure device 13 (writing beam in the drawing), the developing device 14, the cleaning device 15 and the image transfer device 16 (transfer roller in the drawing) are various colors. The four image forming units 10a to 10d are the same in the basic configuration, although there is a slight difference in adjustment depending on the toner characteristics. Further, the photosensitive drum 11, the charging device 12, the developing device 14, and the cleaning device 15 are integrated to form a process cartridge.

  The developing device 14 includes a developing container 6 that contains the one-component toner 5 and a developing roller 1 that is located in an opening extending in the longitudinal direction in the developing container 6 and that is opposed to the photosensitive drum 11. The electrostatic latent image on the photosensitive drum 11 is developed and visualized. Further, the one-component toner 5 is supplied to the developing roller 1 and the toner component roller 5 that scrapes the one-component toner 5 carried on the developing roller 1 without being used for development from the developing roller 1 and the one on the developing roller 1. There is provided a developing blade 8 that regulates the amount of the component toner 5 and frictionally charges the toner.

  The surface of the photosensitive drum 11 is uniformly charged to a predetermined polarity and potential by the charging device 12, and image information is irradiated as a beam from the additional exposure device 13 to the surface of the charged photosensitive drum 11, and an electrostatic latent image is formed. It is formed. Next, one-component toner is supplied from the developing device 14 using the elastic roller of the present invention as the developing roller 1 on the formed electrostatic latent image, and a toner image is formed on the surface of the photosensitive drum 11. As the photosensitive drum 11 rotates, the toner image is transferred to a transfer material 25 such as paper that is supplied in synchronization with the rotation when the toner image comes to a position facing the image transfer device 16.

  In FIG. 4, four image forming units 10 a to 10 d are formed so as to overlap a predetermined color image on one transfer material 25 in series. Therefore, the transfer material 25 is synchronized with the image formation of each image forming unit, that is, the image formation is synchronized with the insertion of the transfer material 25. For this purpose, the transfer roller 17 for transporting the transfer material 25 is sandwiched between the photosensitive drum 11 and the image transfer device 16 so that the drive roller 18, the tension roller 19, and the driven roller 20 of the transfer conveyor belt 17. The transfer material 25 is transported around the transfer transport belt 17 in a form electrostatically attracted to the transfer transport belt 17 by the action of the suction roller 21. Reference numeral 22 denotes a supply roller for supplying the transfer material 25.

  The transfer material 25 on which the image has been formed is peeled off from the transfer conveying belt 17 by the action of the peeling device 23 and sent to the fixing device 24, and the toner image is fixed on the transfer material 25, and printing is completed. On the other hand, the photosensitive drum 11 after the transfer of the toner image to the transfer material 25 is further rotated, the surface is cleaned by the cleaning device 15, and is neutralized by a neutralization device (not shown) as necessary. Thereafter, the photosensitive drum 11 is used for the next image formation. In FIG. 4, reference numerals 26 and 27 denote bias power supplies to the image transfer device 16 and the suction roller 21, respectively.

  Here, the description has been made with respect to the apparatus that directly transfers the toner image of each color onto the tandem type transfer material, but any apparatus that uses the elastic roller of the present invention as the developing roller may be used, and monochrome monochrome image formation is possible. An image forming apparatus that forms a color image by superimposing toner images of each color once on the apparatus, a transfer roller or a transfer belt, and collectively transfers the image to a transfer member, and a development unit of each color is disposed on the rotor, Examples thereof include an image forming apparatus arranged in parallel with a photosensitive drum. Further, instead of the process cartridge, a photosensitive drum, a charging device, a developing device, and the like may be directly incorporated in the image forming apparatus.

  The elastic roller of the present invention can be used not only as the developing roller described above but also for applications requiring conductivity such as a charging roller and a transfer roller because the uniformity of the elastic layer is good.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, these do not limit this invention at all.

  First, measurement methods and evaluations performed in the examples will be described.

(Average primary particle size)
A silicone rubber layer piece was cut out from the elastic roller, and a rubber sample having a thickness of about 100 nm was prepared with an ultramicrotome. Carbon black (silica) in the silicone rubber composition was photographed at a magnification of 100,000 times with a transmission electron microscope (TEM). From the photograph obtained, the projected area of primary particles (100 particles) was determined. The equivalent circle diameter was calculated from the obtained area to determine the volume particle diameter of the particles, and the average value was taken as the average primary particle diameter of carbon black (silica). FIG. 5 shows an image diagram. In FIG. 5, a circle 301 corresponding to the equivalent circle diameter obtained from the projection view is shown.

(Crosslink density ν: Effective network chain concentration for polymer of rubber sample before swelling)
Measurement was performed by a toluene swelling method (applied development of silicone rubber, polymer digest, 1980 (8) P59-60). The silicone rubber layer of the elastic roller is <1> from the surface to a depth of about 500 μm (region 102a), <2> from the surface to a depth of about 500 to 1000 μm from the surface (region 102b), and <3>. Silicone rubber layer test pieces were prepared by cutting out from both ends to 10 mm (region 102c and region 102d) separately. The weight W ₁ and specific gravity ρ ₁ of the test piece were measured first, and then immersed in toluene at room temperature for 72 hours to saturate and swell. Then, the test piece was taken out from the toluene, and the surface toluene was wiped off, and the weight W ₂ was measured. Thereafter, after drying at room temperature for 48 hours or more, the weight W ₃ and the specific gravity ρ ₃ were measured again. Using these values, each test piece was calculated by the following formula.

ν (crosslink density: mol / cm ³ ) =
− (V ₀ / V _s ) (ln (1−V _r ) + V _r + μV _r ² ) / (V _r ^1/3 V ₀ ^2/3 −2V _r / f)
In addition, each symbol of the above formula means the following.
・ V ₁ (initial volume) = W ₁ (initial weight) / ρ ₁ (initial specific gravity)
V ₃ (volume after drying) = W ₃ (weight after drying) / ρ ₃ (specific gravity after drying)
V ₂ (volume when swollen) = V ₃ − (W ₂ (weight when swollen) −W ₃ ) / ρ _s (solvent specific gravity)
Here, the solvent specific gravity ρ _s is 0.866 g / cm ³ of toluene.
V ₀ (polymer volume fraction before swelling) = (V ₃ −V ₁ P) / (V ₁ −V ₁ P)
_Vr (volume fraction of polymer in swollen network chain) = (V ₃ −V ₁ P) / (V ₂ −V ₁ P)
Here, P is the volume fraction of the filler in the sample, silica specific gravity 2.2g / cm ³ , carbon black specific gravity 1.85g / cm ³ , quartz specific gravity 2.65g / cm ³ , diatomaceous earth specific gravity 2.2g / Calculated as cm ³ and polymer specific gravity of 0.98 g / cm ³ .
· V _s (molar volume of solvent) (= 106.8cc / mol)
Μ (Solvent interaction coefficient of polymer) (= 0.413 + 0.361V _r )
F (functional number of crosslinking points) (= 4)

In addition, regarding the crosslinking density ν, each test piece is shown as follows.
Ν ₁ : Crosslink density from the surface of the elastic roller to a depth of 500 μm (region 102a).
Ν ₂ : Crosslink density in the range of 500 μm to 1000 μm in depth from the surface of the elastic roller (region 102b).
Ν ₃ : Crosslink density from one end to 10 mm (region 102c) in the axial direction of the elastic roller.
Ν ₄ : Crosslink density from the opposite end to ν ₃ to 10 mm (region 102d).

(Image evaluation)
Electrophotographic process cartridge (nominal life of 6000 sheets, A4 size, 5% printing rate, print cartridge: black / cyan / magenta) of an image forming apparatus “HP Color LaserJet 3700” (trade name) manufactured by Hewlett-Packard As a yellow developing roller, the developing roller produced in the following examples and comparative examples was incorporated. Next, after the toner was filled, it was incorporated in the image forming apparatus, an image (solid image, halftone image) was output, density unevenness (roller pitch) was visually observed, and evaluated according to the following criteria.
A: Good in all images.
B: Density unevenness is slightly confirmed with solid and halftone, but there is no practical problem.
C: Density unevenness was confirmed in all images.

  Table 1 shows fillers used in the following Examples and Comparative Examples.

[Example 1]
(Preparation of silicone rubber composition)
The main component of silicone rubber is 98.5 parts by mass of dimethylpolysiloxane blocked with both ends of the molecular chain (vinyl group content 0.15% by mass), and the trimethylsiloxy group blocked with dimethylsiloxane-methyl at both ends of the molecular chain as a crosslinking agent. A hydrogen siloxane copolymer (H content of 0.30% by mass bonded to Si atoms) is 1.5 parts by mass, and a complex of chloroplatinic acid and divinyltetramethyldisiloxane (platinum content of 0.5% by mass). %) 0.5 part by mass, 0.04 part by mass of 1-ethyl-1-cyclohexanol and 20 parts by mass of an inorganic filler were blended to prepare a silicone rubber composition. In addition, this inorganic filler consists of carbon black CB-1 (refer Table 1) 70 mass% and the particle | grains which have a silicon atom 30 mass%, and the particle | grains which have a silicon atom are silica FS-1 (refer Table 1) 10 mass. % And quartz powder SI-1 (see Table 1) 90% by mass. Table 2 shows the amount and composition of the inorganic filler.

(Create elastic roller)
An iron shaft core having an outer diameter of φ6 mm is vertically placed on the shaft core body holding shafts (the shaft core upper holding shaft 40 and the shaft core lower holding shaft 39) of the ring coater having the ring type coating head shown in FIG. The clearance between the shaft core 101 and the nozzle of the ring-shaped coating head 38 having an inner diameter of 12.6 mm was set to 3.3 mm.

  The shaft core body was moved by raising the shaft core body holding shaft vertically (10 mm / sec). Accordingly, the silicone rubber composition is discharged at 840 μl / sec to form a silicone rubber composition layer in a cylindrical shape (roll shape) made of the silicone rubber composition on the outer periphery of the shaft core body. A roller having a molded product layer (hereinafter, uncured roller) was prepared.

  This uncured roller is rotated at 60 rpm around the shaft core body, and infrared light (output 1000 W) is applied to the surface of the uncured molded product layer using an infrared heating lamp “HYL25” (trade name) manufactured by Hibeck Co., Ltd. Irradiate for 4 minutes to cure. Note that the distance between the surface of the molded product layer and the lamp during infrared irradiation was 60 mm, and the temperature of the molded product layer surface was 200 ° C. Thereafter, secondary curing at 200 ° C. for 4 hours in an electric furnace is performed for the purpose of stabilizing the physical properties of the cured silicone rubber elastic layer and removing reaction residues and unreacted low molecular components in the elastic layer of silicone rubber. Then, an elastic roller having a conductive silicone layer having a layer thickness of 3.0 mm on the outer periphery of the shaft core body was obtained.

The crosslink densities ν ₁ , ν ₂ , ν ₃ and ν ₄ of the elastic roller 1 were measured as described above, and the ratios ν ₁ / ν ₂ and ν ₃ / ν ₄ were also calculated. The results are shown in Table 3.

(Production roller development)
Polyurethane polyol prepolymer “Takelac TE5060” (trade name, manufactured by Mitsui Takeda Chemical Co., Ltd.) 100 parts by mass, isocyanate “Coronate 2521” (trade name, manufactured by Nippon Polyurethane Co., Ltd.) 77 parts by mass, and carbon black “MA100” (trade name) MEK was added to 24 parts by mass of (Mitsubishi Chemical Corporation) and dispersed with a sand mill for 1 hour. After dispersion, MEK was further added to adjust the film thickness after coating and drying to 20 μm in the range of 20% by mass to 30% by mass to obtain a coating material for the surface layer.

  An elastic roller was immersed in this paint, applied to the surface layer, and then naturally dried. Next, a heat treatment was performed at 140 ° C. for 60 minutes to cure the paint film and obtain a developing roller 1 having a surface layer formed thereon.

(Image evaluation)
The developed developing roller 1 was incorporated into an electrophotographic process cartridge as a developing roller, and an image was output for evaluation. The results are shown in Table 3.

[Example 2]
A silicone rubber composition was obtained in the same manner as in Example 1 except that CB-2 (see Table 1) was used as carbon black, and an elastic roller and a developing roller 2 were produced in the same manner as in Example 1. Table 2 shows the amount and composition of the inorganic filler. Furthermore, Table 3 shows ν ₁ , ν ₂ , ν ₃ and ν ₄ , and ν ₁ / ν ₂ and ν ₃ / ν ₄ of the elastic roller. Table 3 also shows the image evaluation of the developing roller 2.

Example 3
A silicone rubber composition was obtained in the same manner as in Example 1 except that CB-3 (see Table 1) was used as carbon black, and hereinafter, an elastic roller and a developing roller 3 were produced in the same manner as in Example 1. Table 2 shows the composition of the inorganic filler. Furthermore, Table 3 shows ν ₁ , ν ₂ , ν ₃ and ν ₄ , and ν ₁ / ν ₂ and ν ₃ / ν ₄ of the elastic roller. Table 3 also shows the image evaluation of the developing roller 3.

Example 4
A silicone rubber composition was obtained in the same manner as in Example 2 except that the ratio of carbon black CB-2 (see Table 1) and silicon atom-containing particles was changed to 50% by mass and 50% by mass. An elastic roller and a developing roller 4 were manufactured. Table 2 shows the amount and composition of the inorganic filler. Furthermore, Table 3 shows ν ₁ , ν ₂ , ν ₃ and ν ₄ , and ν ₁ / ν ₂ and ν ₃ / ν ₄ of the elastic roller. Table 3 also shows the image evaluation of the developing roller 4.

Example 5
A silicone rubber composition was obtained in the same manner as in Example 3 except that the ratio of carbon black CB-3 (see Table 1) and silicon atom-containing particles was changed to 50% by mass and 50% by mass. An elastic roller and a developing roller 5 were manufactured. Table 2 shows the amount and composition of the inorganic filler. Furthermore, Table 3 shows ν ₁ , ν ₂ , ν ₃ and ν ₄ , and ν ₁ / ν ₂ and ν ₃ / ν ₄ of the elastic roller. Table 3 also shows the image evaluation of the developing roller 5.

Example 6
The main component is 98.0 parts by mass, the crosslinking agent is 2.0 parts by mass, and the composition of the particles having silicon atoms is 5 mass% of silica FS-2 (see Table 1) and 95 mass of diatomaceous earth SI-5 (see Table 1). %, A silicone rubber composition was obtained in the same manner as in Example 1, and an elastic roller and a developing roller 6 were produced in the same manner as in Example 1. Table 2 shows the amount and composition of the inorganic filler. Furthermore, Table 3 shows ν ₁ , ν ₂ , ν ₃ and ν ₄ , and ν ₁ / ν ₂ and ν ₃ / ν ₄ of the elastic roller. Table 3 also shows the image evaluation of the developing roller 6.

Example 7
A silicone rubber composition was obtained in the same manner as in Example 6 except that silica FS-3 (see Table 1) was used as the silica in the particles having silicon atoms. Hereinafter, an elastic roller and a developing roller 7 were obtained in the same manner as in Example 6. Manufactured. Table 2 shows the amount and composition of the inorganic filler. Furthermore, Table 3 shows ν ₁ , ν ₂ , ν ₃ and ν ₄ , and ν ₁ / ν ₂ and ν ₃ / ν ₄ of the elastic roller. Table 3 also shows the image evaluation of the developing roller 7.

Example 8
The main component is 99.0 parts by mass, the crosslinking agent is 1.0 part by mass, and the composition of the particles having silicon atoms is 25 mass% of silica FS-1 (see Table 1) and quartz powder SI-2 (see Table 1) 75. A silicone rubber composition was obtained in the same manner as in Example 1 except that the mass% was changed, and an elastic roller and a developing roller 8 were produced in the same manner as in Example 1. Table 2 shows the amount and composition of the inorganic filler. Furthermore, Table 3 shows ν ₁ , ν ₂ , ν ₃ and ν ₄ , and ν ₁ / ν ₂ and ν ₃ / ν ₄ of the elastic roller. Table 3 also shows the image evaluation of the developing roller 8.

Example 9
A silicone rubber composition was obtained in the same manner as in Example 8 except that silica FS-3 (see Table 1) was used as the silica in the particles having silicon atoms. Hereinafter, an elastic roller and a developing roller 9 were obtained in the same manner as in Example 8. Manufactured. Table 2 shows the amount and composition of the inorganic filler. Furthermore, Table 3 shows ν ₁ , ν ₂ , ν ₃ and ν ₄ , and ν ₁ / ν ₂ and ν ₃ / ν ₄ of the elastic roller. Table 3 also shows the image evaluation of the developing roller 9.

Example 10
A silicone rubber composition was obtained in the same manner as in Example 1 except that the inorganic filler was reduced to 5 parts by mass, and an elastic roller and a developing roller 10 were produced in the same manner as in Example 1 below. Table 2 shows the amount and composition of the inorganic filler. Further, Table 3 shows ν ₁ , ν ₂ , ν ₃ and ν ₄ , and ν ₁ / ν ₂ and ν ₃ / ν ₄ of the elastic roller. Table 3 also shows the image evaluation of the developing roller 10.

Example 11
A silicone rubber composition was obtained in the same manner as in Example 2 except that the main component was 98.0 parts by mass, the crosslinking agent was 2.0 parts by mass, and the inorganic filler was reduced to 5 parts by mass. And the developing roller 11 was manufactured. Table 2 shows the amount and composition of the inorganic filler. Furthermore, Table 3 shows ν ₁ , ν ₂ , ν ₃ and ν ₄ , and ν ₁ / ν ₂ and ν ₃ / ν ₄ of the elastic roller. Table 3 also shows the image evaluation of the developing roller 11.

Example 12
A silicone rubber composition was obtained in the same manner as in Example 3 except that the main component was 98.0 parts by mass, the crosslinking agent was 2.0 parts by mass, and the inorganic filler was reduced to 5 parts by mass. And the developing roller 12 was manufactured. Table 2 shows the amount and composition of the inorganic filler. Furthermore, Table 3 shows ν ₁ , ν ₂ , ν ₃ and ν ₄ , and ν ₁ / ν ₂ and ν ₃ / ν ₄ of the elastic roller. Table 3 also shows the image evaluation of the developing roller 11.

Example 13
A silicone rubber composition was obtained in the same manner as in Example 4 except that the main component was 99.0 parts by mass, the cross-linking agent was 1.0 parts by mass, and the inorganic filler was reduced to 5 parts by mass. And the developing roller 13 was manufactured. Table 2 shows the amount and composition of the inorganic filler. Furthermore, Table 3 shows ν ₁ , ν ₂ , ν ₃ and ν ₄ , and ν ₁ / ν ₂ and ν ₃ / ν ₄ of the elastic roller. Table 3 also shows the image evaluation of the developing roller 13.

Example 14
A silicone rubber composition was obtained in the same manner as in Example 5 except that the main component was 99.0 parts by mass, the cross-linking agent was 1.0 parts by mass, and the inorganic filler was reduced to 5 parts by mass. A developing roller 14 was manufactured. Table 2 shows the amount and composition of the inorganic filler. Furthermore, Table 3 shows ν ₁ , ν ₂ , ν ₃ and ν ₄ , and ν ₁ / ν ₂ and ν ₃ / ν ₄ of the elastic roller. Table 3 also shows the image evaluation of the developing roller 14.

Example 15
Example in which the inorganic filler was reduced to 5 parts by mass, and the composition of particles having silicon atoms was changed to 5% by mass of silica FS-2 (see Table 1) and 95% by mass of quartz powder SI-3 (see Table 1). A silicone rubber composition was obtained in the same manner as in Example 1, and an elastic roller and a developing roller 15 were produced in the same manner as in Example 1. Table 2 shows the amount and composition of the inorganic filler. Furthermore, Table 3 shows ν ₁ , ν ₂ , ν ₃ and ν ₄ , and ν ₁ / ν ₂ and ν ₃ / ν ₄ of the elastic roller. Table 3 also shows the image evaluation of the developing roller 15.

Example 16
A silicone rubber composition was obtained in the same manner as in Example 15 except that silica FS-3 (see Table 1) was used as the silica in the particles having silicon atoms, and hereinafter, an elastic roller and a developing roller 16 were obtained in the same manner as in Example 15. Manufactured. Table 2 shows the amount and composition of the inorganic filler. Furthermore, Table 3 shows ν ₁ , ν ₂ , ν ₃ and ν ₄ , and ν ₁ / ν ₂ and ν ₃ / ν ₄ of the elastic roller. Table 3 also shows the image evaluation of the developing roller 16.

Example 17
Example 1 except that the inorganic filler was reduced to 5 parts by mass, and the composition of particles having silicon atoms was 25% by mass of silica FS-2 (see Table 1) and 75% by mass of diatomaceous earth SI-5 (see Table 1). A silicone rubber composition was obtained in the same manner as in Example 1, and an elastic roller and a developing roller 17 were produced in the same manner as in Example 1. Table 2 shows the amount and composition of the inorganic filler. Furthermore, Table 3 shows ν ₁ , ν ₂ , ν ₃ and ν ₄ , and ν ₁ / ν ₂ and ν ₃ / ν ₄ of the elastic roller. Table 3 also shows the image evaluation of the developing roller 17.

Example 18
A silicone rubber composition was obtained in the same manner as in Example 17 except that silica FS-3 (see Table 1) was used as the silica in the particles having silicon atoms, and hereinafter, an elastic roller and a developing roller 18 were obtained in the same manner as in Example 17. Manufactured. Table 2 shows the amount and composition of the inorganic filler. Furthermore, Table 3 shows ν ₁ , ν ₂ , ν ₃ and ν ₄ , and ν ₁ / ν ₂ and ν ₃ / ν ₄ of the elastic roller. Table 3 also shows the image evaluation of the developing roller 18.

Example 19
A silicone rubber composition was obtained in the same manner as in Example 1 except that the amount of the inorganic filler was increased to 35 parts by mass. Thereafter, an elastic roller and a developing roller 19 were produced in the same manner as in Example 1. Table 2 shows the amount and composition of the inorganic filler. Furthermore, Table 3 shows ν ₁ , ν ₂ , ν ₃ and ν ₄ , and ν ₁ / ν ₂ and ν ₃ / ν ₄ of the elastic roller. Table 3 also shows the image evaluation of the developing roller 19.

Example 20
A silicone rubber composition was obtained in the same manner as in Example 2 except that the main component was 99.0 parts by mass, the cross-linking agent was 1.0 parts by mass, and the inorganic filler was increased to 35 parts by mass. A roller and developing roller 20 were produced. Table 2 shows the amount and composition of the inorganic filler. Furthermore, Table 3 shows ν ₁ , ν ₂ , ν ₃ and ν ₄ , and ν ₁ / ν ₂ and ν ₃ / ν ₄ of the elastic roller. Table 3 also shows the image evaluation of the developing roller 20.

Example 21
A silicone rubber composition was obtained in the same manner as in Example 3 except that the main agent was 99.0 parts by mass, the cross-linking agent was 1.0 parts by mass, and the inorganic filler was increased to 35 parts by mass. A roller and developing roller 21 were produced. Table 2 shows the amount and composition of the inorganic filler. Furthermore, Table 3 shows ν ₁ , ν ₂ , ν ₃ and ν ₄ , and ν ₁ / ν ₂ and ν ₃ / ν ₄ of the elastic roller. Table 3 also shows the image evaluation of the developing roller 21.

[Example 22]
A silicone rubber composition was obtained in the same manner as in Example 4 except that the main agent was 98.0 parts by mass, the crosslinking agent was 2.0 parts by mass, and the inorganic filler was also increased to 35 parts by mass. And the developing roller 22 was manufactured. Table 2 shows the amount and composition of the inorganic filler. Furthermore, Table 3 shows ν ₁ , ν ₂ , ν ₃ and ν ₄ , and ν ₁ / ν ₂ and ν ₃ / ν ₄ of the elastic roller. Table 3 also shows the image evaluation of the developing roller 22.

Example 23
A silicone rubber composition was obtained in the same manner as in Example 5 except that the main agent was 98.0 parts by mass, the crosslinking agent was 2.0 parts by mass, and the inorganic filler was also increased to 35 parts by mass. And the developing roller 23 was manufactured. Table 2 shows the amount and composition of the inorganic filler. Furthermore, Table 3 shows ν ₁ , ν ₂ , ν ₃ and ν ₄ , and ν ₁ / ν ₂ and ν ₃ / ν ₄ of the elastic roller. Table 3 also shows the image evaluation of the developing roller 23.

Example 24
Example in which the inorganic filler was increased to 35 parts by mass, and the composition of the particles having silicon atoms was 5% by mass of silica FS-2 (see Table 1) and 95% by mass of quartz powder SI-4 (see Table 1). A silicone rubber composition was obtained in the same manner as in Example 1, and an elastic roller and a developing roller 24 were produced in the same manner as in Example 1. Table 2 shows the amount and composition of the inorganic filler. Furthermore, Table 3 shows ν ₁ , ν ₂ , ν ₃ and ν ₄ , and ν ₁ / ν ₂ and ν ₃ / ν ₄ of the elastic roller. Table 3 also shows the image evaluation of the developing roller 24.

Example 25
A silicone rubber composition was obtained in the same manner as in Example 24 except that silica FS-3 (see Table 1) was used as the silica in the particles having silicon atoms, and hereinafter, an elastic roller and a developing roller 25 were obtained in the same manner as in Example 24. Manufactured. Table 2 shows the amount and composition of the inorganic filler. Furthermore, Table 3 shows ν ₁ , ν ₂ , ν ₃ and ν ₄ , and ν ₁ / ν ₂ and ν ₃ / ν ₄ of the elastic roller. Table 3 also shows the image evaluation of the developing roller 25.

Example 26
Example in which the inorganic filler was increased to 35 parts by mass, and the composition of particles having silicon atoms was 25% by mass of silica FS-2 (see Table 1) and 75% by mass of quartz powder SI-4 (see Table 1). A silicone rubber composition was obtained in the same manner as in Example 1, and an elastic roller and a developing roller 26 were produced in the same manner as in Example 1. Table 2 shows the amount and composition of the inorganic filler. Furthermore, Table 3 shows ν ₁ , ν ₂ , ν ₃ and ν ₄ , and ν ₁ / ν ₂ and ν ₃ / ν ₄ of the elastic roller. Table 3 also shows the image evaluation of the developing roller 26.

Example 27
A silicone rubber composition was obtained in the same manner as in Example 26 except that silica FS-3 (see Table 1) was used as the silica in the particles having silicon atoms, and hereinafter, an elastic roller and a developing roller 27 were obtained in the same manner as in Example 26. Manufactured. Table 2 shows the amount and composition of the inorganic filler. Furthermore, Table 3 shows ν ₁ , ν ₂ , ν ₃ and ν ₄ , and ν ₁ / ν ₂ and ν ₃ / ν ₄ of the elastic roller. Table 3 also shows the image evaluation of the developing roller 27.

[Comparative Example 1]
Silicone rubber composition as in Example 1 except that the inorganic filler was reduced to 4 parts by mass, and the inorganic filler was composed of 92% by mass of carbon black CB-1 (see Table 1) and 8% by mass of particles having silicon atoms. Thereafter, an elastic roller and a developing roller 28 were produced in the same manner as in Example 1. Table 2 shows the amount and composition of the inorganic filler. Furthermore, Table 3 shows ν ₁ , ν ₂ , ν ₃ and ν ₄ , and ν ₁ / ν ₂ and ν ₃ / ν ₄ of the elastic roller. Table 3 also shows the image evaluation of the developing roller 28.

[Comparative Example 2]
A silicone rubber composition was obtained in the same manner as in Comparative Example 1 except that the composition of the inorganic filler was 45% by mass of carbon black CB-1 (see Table 1) and 55% by mass of particles having silicon atoms. An elastic roller and a developing roller 29 were manufactured. Table 2 shows the amount and composition of the inorganic filler. Furthermore, Table 3 shows ν ₁ , ν ₂ , ν ₃ and ν ₄ , and ν ₁ / ν ₂ and ν ₃ / ν ₄ of the elastic roller. Table 3 also shows the image evaluation of the developing roller 29.

[Comparative Example 3]
The inorganic filler was increased to 36 parts by mass, carbon black CB-4 (see Table 1) was used as carbon black, the composition of particles having silicon atoms was 10% by mass of silica FS-4 (see Table 1) and quartz powder SI. -1 (see Table 1) 90% by mass A silicone rubber composition was obtained in the same manner as in Example 1 except that an elastic roller and a developing roller 30 were produced in the same manner as in Example 1. Table 2 shows the amount and composition of the inorganic filler. Furthermore, Table 3 shows ν ₁ , ν ₂ , ν ₃ and ν ₄ , and ν ₁ / ν ₂ and ν ₃ / ν ₄ of the elastic roller. Table 3 also shows the image evaluation of the developing roller 30.

[Comparative Example 4]
The inorganic filler was increased to 36 parts by mass, carbon black CB-4 (see Table 1) was used as carbon black, the composition of particles having silicon atoms was 3% by mass of silica FS-5 (see Table 1) and quartz powder SI. -1 (see Table 1) Except for 97 mass%, a silicone rubber composition was obtained in the same manner as in Example 1, and the elastic roller and developing roller 31 were produced in the same manner as in Example 1. Table 2 shows the amount and composition of the inorganic filler. Furthermore, Table 3 shows ν ₁ , ν ₂ , ν ₃ and ν ₄ , and ν ₁ / ν ₂ and ν ₃ / ν ₄ of the elastic roller. Table 3 also shows the image evaluation of the developing roller 31.

[Comparative Example 5]
A silicone rubber composition was obtained in the same manner as in Example 1 except that carbon black CB-4 (see Table 1) was used as carbon black, and an elastic roller and a developing roller 32 were produced in the same manner as in Example 1. Table 2 shows the amount and composition of the inorganic filler. Furthermore, Table 3 shows ν ₁ , ν ₂ , ν ₃ and ν ₄ , and ν ₁ / ν ₂ and ν ₃ / ν ₄ of the elastic roller. Table 3 also shows the image evaluation of the developing roller 32.

[Comparative Example 6]
A silicone rubber composition was obtained in the same manner as in Example 1 except that silica FS-4 (see Table 1) was used as silica, and an elastic roller and a developing roller 33 were produced in the same manner as in Example 1. Table 2 shows the amount and composition of the inorganic filler. Furthermore, Table 3 shows ν ₁ , ν ₂ , ν ₃ and ν ₄ , and ν ₁ / ν ₂ and ν ₃ / ν ₄ of the elastic roller. Table 3 also shows the image evaluation of the developing roller 33.

It is a perspective view of an example of the elastic roller of this invention. It is sectional drawing which shows the measurement area | region of the crosslinking density of an elastic layer. It is a schematic explanatory drawing of the ring coat machine used for manufacture of the elastic roller of this invention. 1 is a schematic configuration diagram illustrating an example of an image forming apparatus of the present invention. It is an image figure of the average diameter measurement of a primary particle.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Developing roller 2 Conductive shaft core 3 Elastic layer 4 Conductive resin layer 5 Nonmagnetic one-component toner 6 Developing container 7 Toner supply roller 8 Developing blades 10a to d Image forming unit 11 Photosensitive drum 12 Charging device (charging roller)
13 Image exposure device (writing beam)
14 Developing device 15 Cleaning device 16 Image transfer device (transfer roller)
17 Transfer Conveying Belt 18 Drive Roller 19 Tension Roller 20 Driven Roller 21 Adsorption Roller 22 Supply Roller 23 Peeling Device 24 Fixing Device 25 Transfer Material 26 Bias Power Supply (for Image Transfer Device (Transfer Roller) 16)
27 Bias power supply (for suction roller 21)
31 Mounting base 32 Column 33 Ball screw 34 LM guide 35 Servo motor 36 Pulley 37 Bracket 38 Coating head 39 Shaft core lower holding shaft 40 Shaft core upper holding shaft 41 Supply port 42 Pipe 43 Material supply valve 44 Linear guide 101 Shaft core 102 elastic layer 102a region 102b from the surface of the elastic layer to a depth of 500μm 102b region 102m from the surface of the elastic layer to a depth of 500μm to 1000μm 102c region 102m from one end of the elastic layer 10d from one end of the elastic layer 10mm Up to the region (on the opposite side to 102c)
301 Circle with equivalent circle diameter of projected area of particle

Claims (14)

An elastic roller, wherein an elastic layer made of a silicone rubber composition containing an inorganic filler is formed around a shaft core, and the elastic layer satisfies the following conditions A to C.
Condition A: The compounding amount of the inorganic filler is 5 parts by mass or more and 35 parts by mass or less with respect to 100 parts by mass of the silicone rubber.
Condition B: The composition of the inorganic filler is 10% by mass to 50% by mass of particles having silicon atoms and 90% by mass to 50% by mass of carbon black having an average primary particle size of 10 nm to 40 nm.
Condition C: The silica having an average primary particle size of 7 nm or more and 40 nm or less is 5% by mass or more and 25% by mass or less of the particles having silicon atoms. When the cross-linking density in the region from the surface of the elastic roller to a depth of 500 μm is ν ₁ and the cross-linking density in the region from the surface of the elastic roller is 500 μm to 1000 μm is ν ₂ , ν ₁ / ν ₂ is 0. The elastic roller according to claim 1, wherein the elastic roller is 80 or more and 1.20 or less. The elastic roller according to claim 2, wherein the elastic roller has a crosslinking density ν ₁ and ν ₂ of 5 × 10 ⁻⁵ mol / cc or more and 5 × 10 ⁻⁴ mol / cc or less. In the axial direction of the elastic roller, ₃ a cross-link density in the region from one end portion to 10mm [nu, when the ₄ the crosslink density of 10mm regions [nu from one end portion opposite to the該片end, [nu ₃ / [nu ₄ 0 The elastic roller according to claim 1, wherein the elastic roller is 80 or more and 1.25 or less. 5. The elastic roller according to claim 4, wherein the crosslink density ν ₃ and ν _{4 of the} elastic roller are both 5 × 10 ⁻⁵ mol / cc or more and 5 × 10 ⁻⁴ mol / cc or less. An elastic layer made of a silicone rubber composition containing an inorganic filler is formed around a shaft core, and the elastic layer satisfies the following conditions A to C. A method of manufacturing an elastic roller, comprising:
Condition A: The compounding amount of the inorganic filler is 5 parts by mass or more and 35 parts by mass or less with respect to 100 parts by mass of the silicone rubber.
Condition B: The composition of the inorganic filler is 10% by mass to 50% by mass of particles having silicon atoms and 90% by mass to 50% by mass of carbon black having an average primary particle size of 10 nm to 40 nm.
Condition C: The silica having an average primary particle size of 7 nm or more and 40 nm or less is 5% by mass or more and 25% by mass or less of the particles having silicon atoms.
Process a: A ring-type coating head is arranged so as to be concentric with the shaft core.
Step A: The shaft core is moved in the axial direction relative to the coating head, and an elastic layer material made of a silicone rubber composition is applied from the coating head onto the outer periphery of the shaft core during the movement.
Process c: The elastic layer material applied on the shaft core is cured by infrared heating. When the cross-linking density in the region from the surface of the elastic roller to a depth of 500 μm is ν ₁ and the cross-linking density in the region from the surface of the elastic roller is 500 μm to 1000 μm is ν ₂ , ν ₁ / ν ₂ is 0. It is 80 or more and 1.20 or less, The manufacturing method of the elastic roller of Claim 6 characterized by the above-mentioned. 8. The method for producing an elastic roller according to claim 7, wherein the crosslink density ν ₁ and ν _{2 of the} elastic roller are both 5 × 10 ⁻⁵ mol / cc or more and 5 × 10 ⁻⁴ mol / cc or less. In the axial direction of the elastic roller, ₃ a cross-link density in the region from one end portion to 10mm [nu, when the ₄ the crosslink density of 10mm regions [nu from one end portion opposite to the該片end, [nu ₃ / [nu ₄ 0 The method for producing an elastic roller according to claim 6, wherein the elastic roller is 80 or more and 1.25 or less. 10. The method for producing an elastic roller according to claim 9, wherein the crosslink density ν ₃ and ν _{4 of the} elastic roller are both 5 × 10 ⁻⁵ mol / cc or more and 5 × 10 ⁻⁴ mol / cc or less.   An elastic roller manufactured by the manufacturing method according to claim 6.   The elastic roller according to claim 1, wherein the elastic roller is a developing roller.   An electrophotographic process cartridge in which the elastic roller according to claim 12 is incorporated as a developing roller.   An image forming apparatus in which the elastic roller according to claim 12 is incorporated as a developing roller.

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