JP4906114B2 - Roller manufacturing method, molding material selection method, and molding material - Google Patents

Description

  The present invention relates to a roller manufacturing method, a molding material selection method, and a molding material, and more particularly, a roller manufacturing method capable of manufacturing a roller having a flat elastic layer with high productivity and high reproducibility. The present invention relates to a molding material selection method capable of selecting a molding material capable of forming a flat elastic layer with high reliability, and a molding material capable of forming a flat elastic layer on the outer peripheral surface of a shaft body. .

  Various types of image forming apparatuses using the first-order approximation formula of electrophotography are employed in laser printers, copiers, video printers, facsimiles, and multi-function machines thereof. An image forming apparatus using an electrophotographic linear approximation formula has a shaft and an elastic layer formed on the outer peripheral surface thereof, for example, a cleaning roller, a charging roller, a developing roller, a transfer roller, a pressure roller, a paper feed Various rollers such as a conveyance roller and a fixing roller are provided.

  As an example of these various rollers, a shaft body is manufactured, a liquid rubber composition is injected into a mold equipped with the shaft body, the liquid rubber composition is thermoformed, and the outer periphery of the shaft body Manufactured by forming an elastic layer on the surface. Patent Document 1 states that “a method for forming a conductive elastic layer of a conductive roller is, for example, a composition having a metal support member made of SUS or the like placed in the center by extrusion molding, press molding, Molded by various molding methods such as injection molding, reaction injection molding (RIM), liquid injection molding (LIM), and cast molding, and heat-cured at an appropriate temperature and time to form a conductive elastic layer around the shaft Here, as a manufacturing method of the conductive roller in the present invention, when the conductive composition for forming the elastic layer is liquid, liquid injection molding is preferable in terms of productivity and workability. ing.

  And the molding material which forms the elastic layer of a roller contains various additives other than liquid rubber according to required characteristics, such as a roller and an elastic layer. Examples of such additives include a dispersant, an anti-aging agent, an antioxidant, a filler, a pigment, a colorant, and a plasticizer. When the liquid rubber of the molding material is silicone rubber, for example, inorganic fillers such as diatomaceous earth, pearlite, mica, calcium carbonate, glass flakes are often contained. Examples of such inorganic fillers include synthetic products obtained by synthesis, natural products, by-products produced as by-products in the production process of other substances, and recovered products from various products.

  When the molding material containing these additives is cured on the outer peripheral surface of the shaft body as described above, coarse protrusions may be formed on the surface and inside of the formed elastic layer. When such a roller having a rough convex portion on the surface of the elastic layer is attached to the image forming apparatus, it is a major cause of reducing the quality of an image formed by the image forming apparatus.

  Therefore, in the roller manufacturing method, usually, the molding material is formed into a thin sheet under the same or different conditions as the molding condition of the elastic layer in the roller by testing various physical properties of the molding material, and the resulting thin sheet is convex. A table test that evaluates whether or not a portion is formed and / or a preliminary test that evaluates whether or not a convex portion is formed on an elastic layer by actually making several prototypes of rollers. It is performed prior to actual production. Although it is not a table test concerning the elastic layer, a method for testing a test piece molded under a specific condition with respect to a resin molding material is described in, for example, Patent Document 2. As a method for detecting a surface layer defect of a manufactured roller, for example, a detection method using an optical means is known (see, for example, Patent Document 3).

  However, it has been found that the various physical properties of the molding material have little effect on the formation of coarse protrusions, and the results of the table test and preliminary test do not always match the results of actual production. Even when the test was performed, it was not possible to predict the formation of coarse protrusions in actual production with high reliability. That is, even if these tests were performed in advance and the conditions were set such that a rough convex portion was not formed, a roller having a flat elastic layer could not be manufactured with good reproducibility and yield. In addition, these physical property measurements and tests not only increase the manufacturing process of the roller, but also require a great amount of labor and time for the measurement and testing.

  On the other hand, reduction in manufacturing cost is also required for various rollers employed in the image forming apparatus. If, for example, a by-product, a recovered product, or the like can be used as the inorganic filler, it can greatly contribute to the reduction of the roller manufacturing cost. However, when molding materials containing these by-products and recovered products are used, it is predicted by the physical property characteristics and the test whether or not coarse protrusions are formed on the formed elastic layer. This is more difficult than molding materials containing synthetic products.

JP 2004-271888 A JP 2002-173605 A JP 7-239304 A

  An object of the present invention is to provide a roller manufacturing method capable of manufacturing a roller having a flat elastic layer with high productivity and high reproducibility and yield.

  Another object of the present invention is to provide a molding material sorting method capable of sorting a molding material capable of forming a flat elastic layer with high reliability.

  Furthermore, this invention aims at providing the molding material which can form a flat elastic layer in the outer peripheral surface of a shaft.

As means for solving the problems,
Claim 1 is a method of manufacturing a roller for curing a molding material on the outer peripheral surface of a shaft body, wherein the molding material has a plurality of shear rates (X) selected from a range of 0.01 to 100 sec ^−1. A plurality of first-type normal stress differences (Y (Pa)) obtained by measuring a normal force of the molding material satisfy a first-order approximation expression Y = aX + b with respect to the shear rate (X). A method of manufacturing a roller,
However, in the first-order approximation, 4.5 <a <6.5 and −120 <b <200
Claim 2 is a molding material selection method for selecting a molding material for forming an elastic layer of a roller, wherein a plurality of shear rates (X) selected from a range of a shear rate of 0.01 to 100 sec ⁻¹ are provided. The normal force of the molding material is measured, a plurality of first-type normal stress differences (Y (Pa)) corresponding to the shear rate are obtained, and the obtained first-type normal stress differences (Y (Pa)) ) For the shear rate (X) is calculated, the variable a in the primary approximation is in the range of 4.5 <a <6.5, and the variable b is −120 < a molding material sorting method characterized by sorting molding materials in the range of b <200;
A third aspect of the present invention is a liquid silicone rubber composition that satisfies the first-order approximation of the first aspect.

  The roller manufacturing method according to the present invention forms an elastic layer by curing a molding material satisfying the first-order approximation of the first-type normal stress difference to the shear rate on the outer peripheral surface of the shaft body. It is possible to avoid in advance the use of a molding material containing a large amount of coarse particles that would cause a convex shape to be formed on the surface, and the formation of coarse convex portions is greatly suppressed, and a flat elastic layer is formed. . In particular, when a plurality of rollers are manufactured using such a molding material, a roller having a flat elastic layer formed on the outer peripheral surface of the shaft body can be manufactured with high reproducibility and high yield. In addition, the first type normal stress difference can be measured with a small amount of sample without using any special skill or skill of the measurer if a measuring device with sufficient capacity is used. Judgment based on the approximate expression can be performed easily and in a short time as compared with the physical property measurement, the preliminary test, the table test, and the like that have been conventionally performed. Therefore, according to the present invention, it is possible to provide a method for manufacturing a roller capable of manufacturing a roller having a flat elastic layer with high productivity and high reproducibility and yield.

  Further, in the method for selecting a molding material according to the present invention, the variables a and b in the first-order approximation formula for the shear rate of the first type normal stress difference obtained by measuring the normal force of the molding material are within the above range. It is possible to determine whether a flat elastic layer is formed or an elastic layer having a coarse convex portion is formed depending on whether or not there is a variable in the first-order approximation of the first type normal stress difference. If a molding material in which a and b are within the above ranges is selected, a roller having a flat elastic layer can be produced with high productivity and good reproducibility and yield. Therefore, according to the present invention, it is possible to provide a method for selecting a molding material capable of selecting a molding material capable of forming a flat elastic layer with high reliability.

  Furthermore, since the molding material according to the present invention satisfies the first-order approximation formula of the first-type normal stress difference with respect to the shear rate, as described above, a roller having a flat elastic layer can be produced with high productivity. It can be manufactured with good reproducibility and yield. Therefore, according to this invention, the molding material which can form a flat elastic layer in the outer peripheral surface of a shaft body can be provided.

  As shown in FIG. 1, a roller manufactured by the method for manufacturing a roller according to the present invention includes a shaft body 2 and an elastic layer 3 having a flat surface formed on the outer peripheral surface of the shaft body 2. Thus, as shown in FIG. 2, it is provided with a coating layer 4 formed on the outer peripheral surface of the elastic layer 3, and is disposed, for example, in the image forming apparatus shown in FIG.

  The shaft body 2 only needs to have good conductive properties, and is usually a so-called “core” made of iron, aluminum, stainless steel, brass, or the like. Further, the shaft body 2 may be a shaft body that is made conductive by plating an insulating core body such as a thermoplastic resin or a thermosetting resin. Furthermore, the shaft body 2 may be a thermoplastic resin or a thermosetting resin. The shaft body may be formed of a conductive resin in which carbon black or metal powder is blended as a conductivity imparting agent.

  The elastic layer 3 is formed flat on the outer peripheral surface of the shaft body 2, and specifically, the surface roughness Rz is preferably 2 to 15 μm. When the surface roughness Rz of the elastic layer 3 is 2 to 15 μm, it is possible to efficiently charge and convey a developer having an average powder diameter (diameter) of 5 to 6 μm. The surface roughness Rz of the elastic layer 3 is in accordance with JIS B 0601-1984 (10-point average roughness), and a surface roughness meter (trade name: 590A, manufactured by Tokyo Seimitsu Co., Ltd.) equipped with a measurement probe having a tip radius of 2 μm. The roller 1A provided with the elastic layer 3 is set, and the surface roughness is measured at least at three points with a measurement length of 2.4 mm, a cutoff wavelength of 0.8 mm, and a cutoff type Gaussian. Rz.

The elastic layer 3 is suppressed from forming a rough convex portion on at least its outer peripheral surface so as to satisfy the surface roughness Rz. Here, the coarse convex portion is, for example, a granular protruding portion in which the height of the portion protruding from the surface of the elastic layer is 100 μm or more and / or the maximum diameter of the portion protruding from the surface of the elastic layer is 150 μm or more. The flat elastic layer refers to an elastic layer in which the coarse convex portion is present only in a small number, for example, 1 or less per unit area (1 cm ² ). If there are only a few such rough projections on the outer peripheral surface of the elastic layer, the image forming apparatus has no deterioration in the quality of the image formed by the image forming apparatus even if it is attached to the image forming apparatus. An image can be formed with the original image quality.

  The elastic layer 3 preferably has a JIS A hardness of 10 to 90. When the elastic layer 3 has a JIS A hardness of 10 to 90, for example, when the roller 1A is used as a developing roller, the elastic layer 3 has a contact with a contacted body such as between the blade of the developer regulating member and the image carrier. The nip width can be secured efficiently, and the developer can be efficiently charged and conveyed to easily improve the development efficiency. The JIS A hardness can be measured according to JIS K6253.

The elastic layer 3 preferably has an electric resistance value of 10 ² to 10 ⁹ Ω when used as a developing roller or the like in the image forming apparatus shown in FIG. When the roller 1A used as a roller of an image forming apparatus or the like has an electric resistance value of 10 ² to 10 ⁹ Ω, a desired charge can be reliably charged on the contacted body. For example, when the roller 1A used as the developing roller has an electric resistance value of 10 ² to 10 ⁹ Ω, the developer can be surely carried, and the carried developer is further applied to the image carrier. It can be reliably attached as desired.

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

  The thickness of the elastic layer 3 is preferably 1 mm or more, and more preferably 5 mm or more. On the other hand, the upper limit of the thickness of the elastic layer 3 is not particularly limited as long as the accuracy of the outer diameter of the elastic layer 3 is not impaired. In general, if the thickness of the elastic layer 3 is excessively increased, the production cost of the elastic layer 3 increases. Therefore, in consideration of practical production costs, the thickness of the elastic layer 3 is preferably 30 mm or less, and more preferably 20 mm or less.

  The coat layer 4 is, for example, a resin described later and is formed to a thickness of 1 to 100 μm. Providing the coat layer 4 on the outer peripheral surface of the elastic layer 3 has an effect that the developer can be more efficiently charged and conveyed by its charging characteristics and the like. The material for forming the coat layer 4 is not particularly limited, but when the roller 1B is used in the image forming apparatus shown in FIG. 6 or the like, the roller 1B is in contact with or pressed against the contacted body. Therefore, it is preferable that the material is hard to be permanently deformed, for example, alkyd resin, phenol-modified silicone modified alkyd resin, oil-free alkyd resin, acrylic resin, silicone resin, epoxy resin, fluororesin, phenol Examples thereof include resins, polyamide resins, urethane resins, polyamideimide resins, and mixtures thereof.

  In the roller manufacturing method according to the present invention, first, the shaft body 2 is prepared. The shaft body 2 is made of, for example, a metal such as iron, aluminum, stainless steel, brass or an alloy thereof, a resin such as a thermoplastic resin or a thermosetting resin, and carbon black or metal powder as a conductivity-imparting agent for the resin. It is prepared in a desired shape by a known method using a material such as a conductive resin blended with a body. When the shaft body 2 is required to have conductivity, in addition to the metal and the conductive resin, the surface of the insulating core body formed of the resin or the like is plated by a regular method to thereby form the shaft body 2. Can be formed. Among the above materials, a metal is preferable and aluminum or stainless steel is particularly preferable from the viewpoint that conductivity can be easily imparted.

  In the manufacturing method according to the present invention, a primer application step of applying a primer to the shaft body 2 manufactured in this manner can be performed before the molding step described later. The primer applied to the shaft body 2 is not particularly limited, and examples thereof include alkyd resins, phenol-modified / silicone-modified alkyd resin modified products, oil-free alkyd resins, acrylic resins, silicone resins, epoxy resins, fluororesins, Examples thereof include a phenol resin, a polyamide resin, a urethane resin, and a mixture thereof. Among these, a primer having an amino group and / or a hydroxyl group is preferable. Moreover, as a crosslinking agent which hardens and / or vulcanizes these resin, an isocyanate compound, a melamine compound, an epoxy compound, a peroxide, a phenol compound, a hydrogen siloxane compound etc. are mentioned, for example. The primer is dissolved in a solvent or the like as desired, and is applied to the outer peripheral surface of the shaft body according to a conventional method such as a dipping method or a spray method. The primer layer is formed with a thickness of 0.1 to 10 μm, for example.

  In the manufacturing method according to the present invention, a mold is prepared. The mold used in the elastic layer forming step holds the shaft body 2 and is slightly longer than the elastic layer 3 in the hollow space 14, for example, more than 100% and about 103% with respect to the axial length of the elastic layer 3. A mold having a hollow space 14 having the following length may be used, but a mold in which the inner surface of the hollow space 14 has a mirror surface structure is preferable, and a cylindrical mold having such characteristics is used. It is particularly preferred. Specifically, as a particularly preferable mold, as shown in FIG. 4, a cylindrical hollow body 11 having a hollow space 14, and one end of the cylindrical hollow body 11 are attached, and a liquid rubber composition can be injected. An end piece 12 having a sprue 16 (hereinafter sometimes referred to as a lower end piece), and a vent 18 attached to the other end of the cylindrical hollow body 11 and capable of discharging the liquid rubber composition. The cylindrical metal mold | die 10 provided with the end piece 13 (henceforth an upper end piece) may be mentioned. In the mold, the diameter and length of the hollow space 14 are determined so that the cavity 20 (see FIG. 5) formed when the shaft body 2 is mounted has a predetermined volume.

  As shown in FIG. 4, the sprue 16 of the one end piece 12 has a hollow cross-sectional shape perpendicular to its axis, such as a truncated cone shape extending from the raw material inlet side toward the hollow space 14 side. It is formed in a circular or elliptical shape that gradually expands toward the space 14. In general, the opening angle in the sprue 16 is preferably 1 to 10 degrees, more preferably 2 to 8 degrees, and particularly preferably 3 to 6 degrees. The opening angle of the sprue 16 refers to an angle at which straight lines representing both side surfaces of the sprue 16 intersect in a cross-sectional view of the one end piece 12 passing through the center of the sprue 16. Moreover, it is preferable that the diameter of the raw material inlet side (part with the smallest diameter) of the sprue 16 is 1-10 mm, and it is especially preferable that it is 2-5 mm. By making the sprue 16 into such a shape, the liquid rubber composition can gently and smoothly flow into the hollow space 14 from the sprue 16 to prevent bubbles from being generated in the liquid rubber composition. it can. As shown in FIG. 4, the shape of the vent 18 of the other end piece 13 is a hollow space having a cross-sectional shape perpendicular to the axis thereof, such as a truncated cone shape spreading from the raw material outflow side toward the hollow space 14 side. It is formed in a circle or an ellipse that gradually expands toward 14. The shape of the vent 18 is basically the same as the shape of the sprue 16. The vent 18 is connected to the liquid reservoir 19. The liquid reservoir 19 is a recess that temporarily stores when an excessive liquid rubber composition flows out of the hollow space 14.

In the manufacturing method according to the present invention, a molding material is prepared. It is particularly preferable that the molding material is a liquid rubber composition in that the elastic layer 3 can be easily formed by liquid injection molding. And the molding material used in order to form the elastic layer 3 is obtained by measuring the normal force of the molding material at a plurality of shear rates (X) selected from the range of 0.01 to 100 sec ^−1. The first-order normal stress difference (Y (Pa)) of the first-order approximate expression Y = aX + b with respect to the shear rate (X) is satisfied.

Here, in the primary approximate expression Y = aX + b, Y represents a first-type normal stress difference (Pa), X represents a shear rate “dγ / dt” (1 / s), and 10 ⁻² ≦ X ≦ 10 < ² >, 4.5 <a <6.5, -120 <b <200.

  In the primary approximate expression Y = aX + b, Y is a first-type normal stress difference obtained by measuring the normal force of the molding material under the measurement conditions, and this first-type normal stress difference is sheared into the molding material. This is the difference between the normal stress in the flow direction and the normal stress in the velocity gradient direction when normal stress (tension) is generated in the flow direction due to deformation. It is a physical quantity that indicates the viscoelasticity of the molding material. is there. In the primary approximate expression Y = aX + b, X indicates the time of stress applied to the molding material, and specifically, the shear rate in the measurement. X is a range of 0.01 to 100 in which the linear approximation formula has relatively high linearity.

  The inventor of the present invention, as shown in Examples and Comparative Examples to be described later, actually prepares various molding materials and cures each molding material, and the first approximate expression of each molding material and And a variable a and a variable b in the linear approximation of the molding material, it can be distinguished whether or not coarse particles are formed in the elastic layer formed by curing the molding material, and If the variable a in the linear approximation of the molding material is adjusted to more than 4.5 and less than 6.5 and the variable b is adjusted to more than −120 and less than 200, the elastic layer formed by curing the molding material is coarse. It has been found that the formation of particles can be effectively suppressed. Therefore, in the present invention, the variable a in the first-order approximation Y = aX + b is more than 4.5 and less than 6.5, and the variable b is more than −120 and less than 200. When the variable a is more than 6.5 and / or the variable b is more than 200, a plurality of coarse protrusions may be formed on the elastic layer 3 to be formed. The formation cannot be suppressed with good reproducibility. That is, if each of the variable a and variable b in the linear approximation formula of the molding material is within the range, a roller having a flat elastic layer is manufactured with high productivity and high reproducibility using this molding material. can do. The reason for this is not clear in detail, but when each of the variable a and variable b is within the above range, the liquid rubber, which is a polymer component of the molding material, is filled with the inorganic material according to the first-type normal stress difference. The amount of movement (swelling amount) in the normal direction is larger than that of particulate components such as materials, even if the particle size of the particulate component is large or the shape thereof is not uniform, The component can be pushed into the molding material. As a result, the ratio of the particulate component is reduced on the surface of the elastic layer 3 to be formed, and the flat elastic layer 3 is not formed. I guess. As another reason, it is assumed that the state of entanglement of various molecules contained in the molding material may deteriorate.

  In this invention, even if the variable a is less than 4.5 and / or the variable b is less than −120, a roller having a flat elastic layer can be manufactured. If the ratio b is less and / or the variable b is less than −120, there may be a problem that the preparation process of the molding material is multi-step and the production cost is increased. Therefore, in the present invention, the lower limit values of the variable a and the variable b are set to 4.5 and −120, respectively, in consideration of production costs and the like. However, the variable a and the variable b may be 4.5 and −120 or less as long as a slight increase in production cost can be allowed.

  In the first-order approximation, the variable a is preferably 4.8 or more and 6.2 or less, particularly preferably 5.0 or more and 6.0 or less, and the variable b is −80 or more and 160 or less. It is preferable that it is in particular, and it is particularly preferably −40 or more and 120 or less. When the variable a and the variable b in the linear approximation formula are within these ranges, a roller having a flat elastic layer can be manufactured with higher productivity and higher reproducibility and yield.

In order to calculate the first-order approximate expression, first, a first-type normal stress difference at a plurality of shear rates is obtained. The first type normal stress difference is measured with a viscosity / viscoelasticity measuring device, for example, “Rheostress RS600” (manufactured by Thermo Electron Co., Ltd.), a measurement sensor (for example, C35 / 4 ° cone plate, cone diameter 35 mm). ) If desired, using a temperature control system or the like, the measurement mode is set to the “steady flow viscosity measurement mode”, and the molding material is rotated to measure. Specifically, the torque of the molding material (force applied in the rotation direction of the molding material) measured by the measurement sensor at the _first shear rate X1 selected from the range of 23 ° C. and 0.01 to 100 sec ^−1. ) Continues to be measured at the first shear rate until it reaches a stable value. After the measured torque value reaches a certain value, the first normal force Fn ₁ (force applied perpendicular to the rotation) in the molding material is measured by the measurement sensor. In this way, the first normal force Fn ₁ at the first shear rate X ₁ is measured. Next, similarly, after the measured torque value reaches a constant value at the second shear rate X ₂ selected from the range of 23 ° C. and 0.01 to 100 sec ⁻¹ , the second normal force is obtained. Fn ₂ is measured. This operation is performed a plurality of times, for example, n times, and a plurality of sets (X _n , Fn _n ) of the shear rate X _n and the normal force Fn _n are measured, for example, n sets. From each set (X _n , Fn _n ) of the shear rate X _n and the normal force F _{n n} measured in this way, the first-type normal stress difference N 1 _n at the shear rate X _n is _expressed by the formula N 1 _n = 2 × Fn _n / πR ² (R is the cone radius of the cone plate in the measurement sensor). In this way, a plurality of, for example, n sets (X _n , N1 _n ) of the shear rate X _n and the first type normal stress difference N1 _n are calculated. This method, after continuously measuring a plurality of normal force Fn _n at a plurality of shear rate X _n, but calculates the plurality of first type normal stress difference N1 _n, the normal at each shear rate X _n The first-type normal stress difference N1 _n may be calculated from the above formula every time the force Fn _n is measured.

At this time, as the shear rate, a plurality of values are selected from the range of 0.01 to 100 sec ^−1, and the number n of the selected shear rates may be at least 2, and in order to obtain a more accurate linear approximation formula It is preferably 3 or more. The range in which the plurality of shear rates are selected may be in the range of 0.01 to 100 sec ⁻¹ , but the linearity of the obtained primary approximate expression becomes high, and the variables a and b in the primary approximate expression are accurate. In terms of obtaining a value, for example, it is preferably in the range of 5 to 80 sec ⁻¹ .

The first-order approximate expression Y = aX + b of the first-type normal stress difference N1 _n with respect to the shear rate _Xn thus obtained is calculated. Linear approximation equation Y = aX + b, taking into account the set _(X n, N1 _n) of the plurality of, for example n sets of shear rate _{X n} and the one or normal stress difference N1 _n, conventional techniques, for example, a least It is easily calculated by multiplication or the like. In this way, the primary approximate expression Y = aX + b is calculated. Then, it is confirmed whether or not both the variable a and the variable b in the linear approximation formula are within the range. If both the variable a and the variable b are within the range, the elastic layer 3 is formed. To select as a molding material.

  Examples of the molding material that can satisfy the first order approximation include a liquid silicone rubber composition containing a liquid silicone rubber and an inorganic filler. Examples of the liquid silicone rubber contained in the liquid silicone rubber composition include silicone rubber or silicone-modified rubber, nitrile rubber, ethylene propylene rubber (including ethylene propylene diene rubber), styrene butadiene rubber, butadiene rubber, isoprene rubber, natural Examples thereof include liquid rubbers such as rubber, acrylic rubber, chloroprene rubber, butyl rubber, epichlorohydrin rubber, urethane rubber, and fluorine rubber. These rubbers are preferably an addition-curing type because they are excellent in dimensional accuracy during heat molding.

  Examples of the inorganic filler contained in this liquid silicone rubber composition include diatomaceous earth, pearlite, mica, calcium carbonate, glass flakes, and hollow filler, among which diatomaceous earth, pearlite, and foamed pearlite are pulverized products. preferable. In this invention, as the inorganic filler, synthetic products obtained by synthesis, natural products, by-products produced as a by-product in the production process of other substances, recovered products from various products, etc. are used without particular limitation. Can do. Inorganic fillers are natural products, by-products, in which non-uniform shapes, particle sizes, etc. are mixed, in that the object of the present invention can be achieved well and the production cost of the roller can be reduced. It is recommended to use recovered items. As natural products, by-products, and recovered products, for example, the trade name “LocaHelp 4209” (Perlite, manufactured by Mitsubishi Metal Industries, Ltd.), the trade name “Oplite W-3005S” (diatomaceous earth, manufactured by Hokuaki Diatomite Co., Ltd.), and the trade name “ “Radiolite F” (diatomaceous earth, manufactured by Showa Chemical Industry Co., Ltd.), trade name “Crystallite VX-S” (quartz powder, manufactured by Tatsumori Co., Ltd.), and the like. In particular, according to the present invention, even if the shape, particle diameter, etc. of the inorganic filler are non-uniform, the elastic layer, contrary to expectation, if the molding material containing the inorganic filler satisfies the linear approximation formula, 3 can suppress the formation of convex portions, the outer peripheral surface thereof becomes flat, and even if a plurality of rollers are manufactured, a flat elastic layer is formed with high reproducibility and high yield. can do.

  The object of the present invention can be achieved as desired, and the manufacturing cost of the roller can be greatly reduced. Inorganic fillers such as the trade name “LocaHelp”, the trade name “Oplite”, etc. A by-product or a recovered product is particularly preferable.

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

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

In particular, the liquid conductive rubber composition is preferably an addition-curing liquid conductive silicone rubber composition because the elastic layer 3 having a flat surface can be easily formed. The liquid conductive rubber composition includes, for example, (A) an organopolysiloxane containing at least two alkenyl groups bonded to a silicon atom in one molecule, and (B) a hydrogen atom bonded to a silicon atom in one molecule. An organohydrogenpolysiloxane containing at least two and (C) an inorganic filler having an average particle diameter of 1 to 30 μm and a bulk density of 0.1 to 0.5 g / cm ³ (also referred to as an inorganic filler). And (D) a conductivity-imparting agent and (E) an addition reaction catalyst, an addition-curable liquid conductive silicone rubber composition.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  The liquid rubber composition is made of rubber, a conductivity imparting agent, and various additives added as desired using a rubber kneader such as a two-roller, three-roller, roller mill, Banbury mixer, and dough mixer (kneader). For example, it can be obtained by kneading at a normal temperature or under heating for several minutes to several hours, preferably 5 minutes to 1 hour until they are uniformly mixed. In particular, when the liquid rubber composition is the addition-curable liquid conductive silicone rubber composition, the organopolysiloxane (A), the inorganic filler (C), and the (D) conductivity-imparting agent are added. It is preferable to uniformly mix in advance using a rubber kneader or the like. If these components are uniformly mixed in advance, the first-order approximation formula can be satisfied relatively easily when an addition-curable liquid conductive silicone rubber composition is obtained. The mixing time at this time is appropriately adjusted according to the rubber kneader to be used. However, if the mixing time is too long, productivity may be sacrificed, for example, from several minutes to less than 1 hour, preferably 5 to 50 minutes. The mixing temperature is not particularly limited, and is normal temperature or under heating.

  The liquid rubber composition may have a viscosity of 5 to 500 Pa · s at 25 ° C., for example, in that the liquid rubber composition can be easily and uniformly injected into a mold described later. It is particularly good to have a viscosity of s. The viscosity of the liquid rubber composition can usually be adjusted by the type and / or blending amount of each component contained therein. If necessary, the viscosity can be adjusted with a solvent or the like.

  In the manufacturing method according to the present invention, as shown in FIG. 5, the manufactured shaft body 2 and the prepared mold 10 are then assembled. That is, as shown in FIG. 5, the lower end piece 12 is arranged on the lower side of the cylindrical hollow body 11, the upper end piece 13 is arranged on the upper side, and the shaft body 2 is passed through the cylindrical hollow body 11. The mold 10 is assembled such that both ends are sandwiched between the holding hole 15 of the lower end piece 12 and the holding hole 17 of the upper end piece 13. Needless to say, the shaft body 2 is arranged so as to coincide with the axis of the hollow space 14.

  In the manufacturing method according to the present invention, the molding material having the above characteristics is then injected into the cavity 20 of the assembled mold 10. Any method can be employed as the method for injecting the molding material into the cavity 20 as long as it is a regular method. Examples thereof include injection by an injection molding machine and injection by a casting machine.

  In the manufacturing method according to the present invention, the molding material injected into the cavity 20 is then heated together with the mold 10 to mold the elastic layer 3. The heating conditions may be any conditions as long as the molding material can be cured. For example, the heating temperature can be set to 100 to 300 ° C., and the heating time can be set to 10 seconds to 1 hour.

  In the production method according to the present invention, for the purpose of reducing the compression set, secondary vulcanization can be performed after the heating at a heating temperature of 120 to 250 ° C. for about 30 minutes to 70 hours.

  In this way, the flat elastic layer 3 is formed on the outer peripheral surface of the shaft body 2.

  In the manufacturing method according to the present invention, the coat layer 4 can be formed on the outer peripheral surface of the formed elastic layer 3 as desired. When forming the coat layer 4, it is preferable to form the coat layer 4 after applying ultraviolet treatment and / or a primer to the outer peripheral surface of the elastic layer 3. The adhesion between the outer peripheral surface of the elastic layer 3 and the coat layer 4 can be improved by applying an ultraviolet treatment and / or a primer to the outer peripheral surface of the elastic layer 3. The ultraviolet treatment and / or primer application may be carried out independently, but it is more preferred to carry out a combination of both. The coating layer 4 is prepared by dissolving a material described later in a solvent or the like as desired, and is applied to the outer peripheral surface of the elastic layer 3 by a usual method, for example, spray coating, dipping, in-mold coating method, etc. Or it is formed by vulcanization. The coat layer 4 can also be formed by inserting the elastic layer 3 into a shrink tube previously formed into a cylindrical shape and shrinking the shrink tube by heating. The coating layer 4 is prepared by dissolving a material described later in a solvent or the like as desired, and is applied to the outer peripheral surface of the elastic layer 3 according to a conventional method, for example, a dip method or a spray method, and the material is cured and / or vulcanized. ,It is formed.

  In the method for manufacturing a roller according to the present invention, since a molding material that satisfies the first-order approximation formula is used, a roller in which a flat elastic layer is formed on the outer peripheral surface of the shaft body has high reproducibility and good yield. Can be manufactured.

In the present invention, as described above, when a molding material that satisfies the first-order approximation formula is used, a flat elastic layer is formed with high reproducibility and good yield. Therefore, before manufacturing the roller, the molding material for forming the elastic layer, as described above, has a plurality of shear rates X _n selected from the range of the shear rate of 0.01 to 100 sec ⁻¹ and a plurality of first speeds. A set (X _n , N1 _n ) with a kind of normal stress difference N1 _n is calculated, and a first-order approximate expression Y = aX + b of the first kind of normal stress difference (Y (Pa)) with respect to the shear rate (X) is To calculate the molding material in which the variable a in the linear approximation formula is in the range of 4.5 <a <6.5 and the variable b is in the range of −120 <b <200. If the molding material is selected and a molding material in which the variable a and the variable b in the linear approximation formula are not in the above range is selected, the physical property measurement, the preliminary test, the table test, and the like that have been conventionally performed are not performed. Even with a roller with a flat elastic layer It can be manufactured with high productivity and good reproducibility and yield.

That is, the molding material selection method according to the present invention measures the normal force of the molding material at a plurality of shear rates (X) selected from the range of the shear rate of 0.01 to 100 sec ⁻¹ and corresponds to the shear rate. A plurality of first-type normal stress differences (Y (Pa)) to be obtained, a first-order approximate expression Y = aX + b for the shear rate of the obtained first-type normal stress differences is calculated, and a variable in the first-order approximate expression selecting a molding material in which a is in the range of 4.5 <a <6.5 and variable b is in the range of −120 <b <200 as the molding material for forming the elastic layer of the roller. Features.

  In the molding material selection method according to the present invention, the first-type normal stress difference and the primary approximation formula in the molding material are as described above, and the calculation method of the primary approximation formula is also as described above.

  In the molding material selection method according to the present invention, it is confirmed whether or not each of the variable a and the variable b in the linear approximation calculated as described above is within the range. A molding material in which both the variable a and the variable b are within the above range is preferably selected as a molding material for forming a flat elastic layer in the roller, while at least one of the variable a and the variable b is within the above range. The molding material that is not present is not selected as the molding material that forms the flat elastic layer in the roller. As described above, according to the method for selecting a molding material according to the present invention, as a molding material for forming a flat elastic layer, whether or not the variable a and the variable b in the linear approximation formula of the molding material are in the above range. The accuracy can be judged with high reliability.

  Therefore, according to the method for selecting a molding material according to the present invention, as described above, a flat elastic layer is formed as compared with the physical property measurement, the preliminary test, the table test, and the like that have been conventionally performed. Therefore, it is possible to easily determine the accuracy as a molding material that can be formed, and to select a molding material that can form a desired elastic layer without greatly sacrificing the productivity of the roller. it can.

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

  The developing means 40 in the image forming apparatus 30 is basically formed in the same manner as the developing means provided in the conventional image forming apparatus, and is arranged in the same manner. For example, as shown in FIG. 6, the developing unit 40 has an opening at a position facing the image carrier 31, and includes a developer storage unit 41 that stores the developer 42, and a developer storage unit 41. An agitator 43 for uniformly agitating the developer 42, and an opening of the developer accommodating portion 41. The agitator 43 is in contact with or pressed against the image carrier 31 or at a predetermined interval. A rotatable developer carrier 44 for supplying the developer 42 with a constant layer thickness to the developer 31 and a developer carrier 44 provided above the developer carrier 44 and in contact with the developer carrier 44 are provided. And a developer regulating member 45 that charges the developer 42 by frictional charging. Specifically, the developer regulating member 45 is disposed at the opening of the developing unit 40 such that the blade 46 is curved so that the blade 46 contacts the surface of the developer carrier 44 with a predetermined pressure. Yes. The developer 42 accommodated in the developer accommodating portion 41, that is, the developer 42 used in the image forming apparatus 30 according to the present invention, is a one-component system that can be charged by friction and can be fixed to the recording paper 36. The developer may be a dry developer or a wet developer, and may be a non-magnetic developer or a magnetic developer.

  The image forming apparatus 30 according to the present invention includes a charging roller of the charging unit 32, a developing roller of the developing unit 40, a transfer roller of the transfer unit 34, a fixing roller of the fixing unit 35, a cleaning roller (not shown) of the cleaning unit, and an addition. Various rollers such as a pressure roller (not shown) and a paper feed / conveying roller (not shown) are provided, and a roller 1 manufactured by the method for manufacturing a roller according to the present invention is mounted as at least one of these rollers. Has been. Preferably, a roller 1 manufactured by the method for manufacturing a roller according to the present invention is mounted as at least one of a charging roller, a developing roller, a transfer roller, and a fixing roller.

  The image forming apparatus 30 according to the present invention operates as follows. First, the image carrier 31 rotates clockwise as indicated by the arrow in FIG. 6, and after the developer 42 and / or dust and the like on the surface thereof are removed by the cleaning unit 37, the charging unit 32. Thus, it is uniformly charged. Next, the image is exposed by the exposure means 33, and an electrostatic latent image is formed on the surface of the image carrier 31.

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

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

  The image forming apparatus 30 according to the present invention includes a charging roller, a developing roller, a transfer roller, a fixing roller, a cleaning roller (not shown), a pressure roller (not shown), a paper feed / conveying roller (not shown), and the like. Since the roller 1 manufactured by the method for manufacturing a roller according to the present invention is mounted as at least one of the various rollers, the roller mounted with the roller 1 manufactured by the method for manufacturing a roller according to the present invention is Therefore, it can act uniformly on the contacted body, and can contribute sufficiently to forming a high-quality image.

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

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

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

Example 1
First, the mold shown in FIG. 4 and the shaft body 2 were prepared. That is, the mold 10 including the hollow cylindrical body 11, the lower end piece 12, and the upper end piece 13 shown in FIG. 4 and having a hollow space 14 having a diameter (outer diameter) of 35 mm, an (inner diameter) of 20.7 mm, and a length of 240 mm. Produced. Each of the lower end piece 12 and the upper end piece 13 has a thickness of 25 mm, and holding holes 15 and 17 having a diameter of 7.5 mm are formed in the inner center portion thereof. Further, the lower end piece 12 is formed with a frustoconical sprue 16 having a central axis at a position 8.25 mm from the central axis. The sprue 16 has a diameter of 2.5 mm on the raw material inlet side and a hollow space 14. The side diameter is 3.0 mm. As shown in FIG. 4, the upper end piece 13 is provided with a frustoconical vent 18 having a central axis at a position 8.25 mm from the central axis, and a liquid reservoir 19 at the upper portion thereof. The depth is 20 mm, the vent 18 is 5 mm long, the opening diameter on the liquid reservoir 19 side is 2.5 mm, and the opening diameter on the hollow space 14 side is 3.0 mm. Eight sprues 16 and eight vents 18 are equally arranged in the circumferential direction. The inner surface of the cylindrical hollow body 11 was mirror-finished according to a conventional method.

  Next, the shaft body 2 (made by SUM22, diameter 7.5 mm, length 281.5 mm) subjected to electroless nickel plating treatment was washed with toluene, and a silicone primer (trade name “Primer No. 16”) was formed on the surface thereof. , Manufactured by Shin-Etsu Chemical Co., Ltd.). The shaft body subjected to the primer treatment was fired at a temperature of 150 ° C. for 10 minutes using a gear oven, and then cooled at room temperature for 30 minutes or more to form a primer layer on the surface of the shaft body 2.

  Next, a mold release agent (trade name “Die Free” manufactured by Daikin Industries, Ltd.) was applied to the mold 10, and the shaft body 2 made of the holding hole 15 of the lower end piece 12 and the holding hole 17 of the upper end piece 13. Was held in the center of the hollow space 14 to assemble the mold 10.

On the other hand, an addition curable liquid conductive silicone rubber composition 1 was prepared as follows. That is, 100 parts by mass of dimethylpolysiloxane (A) (degree of polymerization 300) blocked at both ends with dimethylvinylsiloxy groups, and a hydrophobized fumed silica having a BET specific surface area of 110 m ² / g (Nippon Aerosil Co., Ltd.) Made by company, R-972) 1 part by mass, average particle size 6 μm, pearlite (C) having a bulk density of 0.25 g / cm ³ (trade name “LocaHelp 4209”, manufactured by Mitsubishi Metal Industries, Ltd.), 20 parts by mass, And, 5 parts by mass of acetylene black (D) (Denka Black HS-100, manufactured by Denki Kagaku Kogyo Co., Ltd.) was put in a planetary mixer, stirred for 30 minutes, and then passed once through three rolls. This is returned to the planetary mixer again, and methylhydrogenpolysiloxane (B) having Si—H groups at both ends and side chains as a crosslinking agent (polymerization degree 17, Si—H amount 0.0060 mol / g) 2. 1 part by mass, 0.1 part by mass of ethynylcyclohexanol and 0.1 part of platinum catalyst (E) (Pt concentration 1%) were added as a reaction control agent, and the mixture was stirred and kneaded for 15 minutes.

The first-type normal stress difference in this addition-curable liquid conductive silicone rubber composition 1 was calculated according to the above method, and a first-order approximate expression of the first-type normal stress difference N1 _n with respect to a plurality of shear rates _Xn was obtained. . The primary approximate expression of the addition-curable liquid conductive silicone rubber composition 1 obtained in this way is Y = 5.78X + 41.1 (R ² = 0.938), and the straight line 1 and plot ( (Black triangle).

  Table 1 shows the results of measuring the viscosity (23 ° C.) and compression set (180 ° C., 22 hours) of the addition-curable liquid conductive silicone rubber composition 1 in accordance with the method described in JIS K6301. Show.

  Next, a mold release agent (trade name “Die Free” manufactured by Daikin Industries, Ltd.) was applied to the inner surface of the mold 10 to produce the holding hole 15 of the lower end piece 12 and the holding hole 17 of the upper end piece 13. After the shaft body 2 is held in the center of the hollow space 14, the mold 10 is assembled, and the addition-curable liquid conductive silicone rubber composition 1 flows out from the vent 18 to the liquid reservoir 19 through the sprue 16 of the lower end piece 12. The cavity 14 was injected until it started. Subsequently, it heated at 150 degreeC from the exterior of the metal mold | die 10, and hold | maintained for 10 minutes at the same temperature, and the addition-curable liquid conductive silicone rubber composition 1 was heat-molded. After the heat molding, the mold 10 is allowed to cool and the molded product is taken out from the mold 10, and the sprue 16 and the vent 18 portions where the rubber is adhered are cut and removed, and the roller 1a provided with the elastic layer 3 is removed. 100 were manufactured.

(Example 2)
Addition-curing liquid conductive material in the same manner as in Example 1 except that perlite (C ′) (trade name “LocaHelp 4209”) having a different production lot was used for the perlite (C) (tradename “LocaHelp 4209”). Silicone rubber composition 2 was prepared. When the first-order approximate expression in the addition-curable liquid conductive silicone rubber composition 2 was determined in the same manner as in Example 1, Y = 5.74X + 20.2 (R ² = 0.886), which is shown in FIG. A straight line 2 and a plot (black circle) are shown. Further, the viscosity (23 ° C.) and compression set of the addition-curable liquid conductive silicone rubber composition 2 were measured, and the results are shown in Table 1. Using this addition-curable liquid conductive silicone rubber composition 2, 100 rollers 1b were produced in the same manner as in Example 1.

Example 3
Addition curing in the same manner as in Example 1 except that diatomaceous earth (trade name “Oplite W-3005S”, manufactured by Kitaaki Diatomaceous Earth Co., Ltd.) was used instead of the perlite (C) (trade name “LocaHelp 4209”). A mold type liquid conductive silicone rubber composition 3 was prepared. When the first-order approximation formula for the addition-curable liquid conductive silicone rubber composition 3 was determined in the same manner as in Example 1, Y = 6.1X + 150.1 (R ² = 0.936), which is shown in FIG. This is indicated by the straight line 5. Further, the viscosity (23 ° C.) and compression set of the addition-curable liquid conductive silicone rubber composition 2 were measured, and the results are shown in Table 1. Using this addition-curable liquid conductive silicone rubber composition 3, 100 rollers 1c were produced in the same manner as in Example 1.

(Comparative Example 1)
The same as Example 1 except that the dimethylpolysiloxane (A), the pearlite (C), and the acetylene black (D) were put into a planetary mixer and stirred for 30 minutes, but were not passed through a three-roll. Thus, an addition-curable liquid conductive silicone rubber composition 4 was prepared. When the first-order approximate expression in the addition-curable liquid conductive silicone rubber composition 3 was determined in the same manner as in Example 1, Y = 6.58X + 200 (R ² = 0.840), and the straight line in FIG. (Broken line) 3 and a plot (black square). Further, the viscosity (23 ° C.) and compression set of the addition curable liquid conductive silicone rubber composition 4 were measured, and the results are shown in Table 1. Using this addition-curable liquid conductive silicone rubber composition 4, 100 rollers 1d were produced in the same manner as in Example 1.

(Comparative Example 2)
Addition-curing liquid conductivity as in Example 1, except that the dimethylpolysiloxane (A), the pearlite (C), and the acetylene black (D) were put into a planetary mixer and stirred for 60 minutes. Silicone rubber composition 5 was prepared. When the first-order approximate expression in the addition-curable liquid conductive silicone rubber composition 5 was determined in the same manner as in Example 1, Y = 4.43X-122 (R ² = 0.817), which is shown in FIG. A straight line (broken line) 4 and a plot (black rhombus) are shown. Further, the viscosity and compression set of the addition curable liquid conductive silicone rubber composition 5 were measured, and the results are shown in Table 1. Using this addition-curable liquid conductive silicone rubber composition 5, 100 rollers 1e were produced in the same manner as in Example 1.

(Comparative Example 3)
Example 1 is the same as Example 1 except that perlite (C ″) (product name “LocaHelp 4209”) whose production lot of the perlite (C) (product name “LocaHelp 4209”) is different from Example 1 and Example 2 was used. Similarly, an addition curable liquid conductive silicone rubber composition 6 was prepared. When the first-order approximation formula for the addition-curable liquid conductive silicone rubber composition 6 was determined in the same manner as in Example 1, Y = 3.58X + 39.1 (R ² = 0.901). This is indicated by a straight line (broken line) 6. Further, the viscosity (23 ° C.) and compression set of the addition curable liquid conductive silicone rubber composition 6 were measured, and the results are shown in Table 1. Using this addition-curable liquid conductive silicone rubber composition 6, 100 rollers 1f were produced in the same manner as in Example 1.

  Using the addition curable liquid conductive silicone rubber compositions 1 to 6, a table test was performed by the following method, and six of the 100 rollers manufactured in the respective experimental examples were manufactured as the first to sixth rollers. Preliminary tests were carried out using these rollers. Table 1 shows the total number of coarse protrusions (granular protrusions having a height of 100 μm or more and / or a maximum diameter of 150 μm or more) visually confirmed in these tests.

Preliminary test The number of convex portions was counted by visually observing the surface of each of the six selected rollers.
-Table test After placing an appropriate amount of the addition curable liquid conductive silicone rubber composition 1-6 on FX4200 paper (manufactured by Xerox Co., Ltd.), a frame of 5 cm x 10 cm x 0.5 mm thickness is immediately formed on the composition. Placed on top. Subsequently, this composition was sheeted to a predetermined size with a spatula or the like that can obtain a uniform thickness such as a doctor blade, and was heat-cured under conditions of 80 ° C. × 1 hour. The number of convex portions in the sheet thus cured was visually observed to count the number of convex portions.

  In addition, the yield in the examples and comparative examples (the ratio (%) of the total number of rollers in which the coarse protrusions were recognized in the elastic layer to the total number of inspections 100) was calculated, and the results are shown in Table 1. .

  In Comparative Example 2, since the variable a and the variable b in the linear approximation formula in the addition curable liquid conductive silicone rubber composition 5 are both near the lower limit value, the results of the table test, the preliminary test, and the yield are compared. Although it is good, since the stirring time is doubled, there is a problem that productivity is lowered and additional processes are added, leading to cost increase.

  As shown in Table 1, although the viscosity and compression set of the addition curable liquid conductive silicone rubber compositions 1 to 6 were almost the same, the yield was greatly different. It was also found that the results of the table test and the preliminary test did not match the yield results. Thus, in the conventional physical property measurement, preliminary test and table test, etc., these results do not necessarily match the actual production results, and the physical property measurement, preliminary test and table test, etc. Even if the manufacturing conditions and the like were adjusted from the above results, it was not possible to manufacture a roller having a flat elastic layer with high productivity and good reproducibility and yield. According to Examples 1 to 3 using a molding material having a predetermined range, a roller having a flat elastic layer could be manufactured with high productivity and high reproducibility and yield.

FIG. 1 is a perspective view showing an example of a roller. FIG. 2 is a perspective view showing another example of the roller. FIG. 3 is a graph showing the relationship between the shear rate of the molding material and the first-type normal stress difference in the present invention. FIG. 4 is a cross-sectional view showing a state in which a mold suitably used in the manufacturing method according to the present invention is assembled. FIG. 5 is a cross-sectional view showing a state when a shaft body is mounted on a mold suitably used in the manufacturing method according to the present invention. FIG. 6 is a schematic view showing an example of an image forming apparatus according to the present invention.

Explanation of symbols

1A, 1B Roller 2 Shaft body 3 Polishing-less elastic layer 4 Coat layer 10 Mold 11 Cylindrical hollow body 12 Lower end piece 13 Upper end piece 14 Hollow space 15, 17 Holding hole 16 Sprue 18 Vent 18d Opening 19 Liquid reservoir 20 Cavity 30 Image forming apparatus 31 Image carrier 32 Charging means 33 Exposure means 34 Transfer means 35 Fixing means 36 Transfer paper 37 Cleaning means 40 Developing means 41 Developer storage section 42 Developer 43 Stirrer 44 Developer carrier 45 Developer regulating member 46 Blade

Claims (3)

A method of manufacturing a roller for curing a molding material on an outer peripheral surface of a shaft body,
The molding material has a plurality of first-type normal stress differences (Y (Y ()) obtained by measuring normal forces of the molding material at a plurality of shear rates (X) selected from a range of 0.01 to 100 sec ^−1. Pa)) satisfying the first order approximate expression Y = aX + b with respect to the shear rate (X).
However, in the first-order approximation, 4.5 <a <6.5 and −120 <b <200 A method for selecting a molding material for selecting a molding material for forming an elastic layer of a roller,
A normal force of the molding material is measured at a plurality of shear rates (X) selected from a range of a shear rate of 0.01 to 100 sec ⁻¹ , and a plurality of first-type normal stress differences corresponding to the shear rates ( Y (Pa)),
Calculate the first-order approximate expression Y = aX + b of the obtained first type normal stress difference (Y (Pa)) with respect to the shear rate (X),
The molding material is characterized by selecting a molding material in which the variable a in the linear approximation formula is in the range of 4.5 <a <6.5 and the variable b is in the range of -120 <b <200. Sorting method.   A liquid silicone rubber composition satisfying the first-order approximation according to claim 1.

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