JP2013040627A - Apparatus for manufacturing elastic roller and method for manufacturing elastic roller using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus and a method for manufacturing an elastic roller that prevents the variation of a roller outer diameter due to the variation of a discharge amount of an extruder caused by pressure variation generated at a discharge part.SOLUTION: The elastic roller is manufactured by the apparatus using a cross head in which a portion of an annular flow path wall surface is subjected to nitriding treatment while the other region is subjected to surface treatment different from the nitriding treatment, and thereby the adhesive property of raw materials is enhanced as compared to the other region forming the wall surface.

Description

  The present invention relates to an apparatus for manufacturing an elastic roller such as a rubber roller coated with a rubber layer used for a charging roller, a paper feed roller, or the like used in an electrophotographic apparatus such as a printer or a copying machine, or an office machine, and the like. The present invention relates to a method for manufacturing an elastic roller. In particular, the present invention relates to an apparatus for manufacturing an elastic roller having a crown shape by changing the thickness of a rubber layer coated in the axial direction of a cored bar, and an elastic roller manufacturing method using the apparatus.

  Usually, a charging roller, a paper feed roller, and the like used in a printer, a copier, and the like are often rotated by being brought into contact with a rotating photosensitive drum at a predetermined pressure. The charging roller or the like is pressed against the photosensitive drum or the like by pressing a core bar protruding from both ends of the roller. For this reason, the core metal bends due to this pressure contact force, and the rubber strain (degree of compression) differs between the two end portions and the center portion of the rubber layer, and the nip area (unit length of contact) of the pressure contact portion with the photosensitive drum or the like. There is a problem that the area) is large at both ends and small at the center. If the nip area is not uniform, for example, a paper feed roller causes uneven circumferential speed in the longitudinal direction, causing skewing and wrinkling of the paper. When used as a charging roller, the electric field strength is not in the axial direction of the roller. It becomes uniform, uneven charging occurs, and a defect may occur in the image.

  Conventionally, in order to make the nip area uniform, it has been known that the rubber roller has a crown shape in which the diameter gradually increases from both ends toward the center. After fully kneading the unvulcanized rubber composition at a predetermined temperature with an extruder, extrusion molding is performed at a predetermined speed, and the outer periphery of the core metal is coated with a predetermined thickness with a crosshead to form an unvulcanized rubber roller. Then, this is vulcanized to obtain a charging roller or the like. As a method of forming a crown shape in the rubber roller, there is a method in which the outer peripheral surface of the rubber roller is ground and polished into a crown shape by a polishing machine or the like after vulcanization. Further, there is a method in which an unvulcanized rubber roller is filled into a mold having a cavity that has been previously molded into a crown shape, and the crown shape is formed simultaneously with vulcanization. In addition, by changing the speed at which the core metal is fed into the cross head or the speed at which the core metal is taken out from the cross head, the rubber layer coated on the outer periphery of the core metal is changed in the axial direction of the core metal, and simultaneously with the molding. There is a method of creating a crown shape (hereinafter referred to as crown extrusion). The speed at which the mandrel is fed into the crosshead is called a mandrel governing profile.

  In the present invention, the outer diameter profile and the core metal speed regulation profile of the rubber roller from the one end to the center and from the other end to the center are symmetrical in the core metal axis direction when the central position in the core metal axis direction is the origin. Is simply called symmetric or left-right symmetric.

In this crown extrusion molding method, even if the core metal speed control profile by the apparatus-side condition setting is symmetrical in the core metal axis direction, depending on the molding conditions, the crown shape is affected by the responsiveness / following performance of the rubber material. May not be symmetric in the axial direction of the rubber roller, resulting in a difference in outer diameter. (Hereinafter, in the present invention, the above-mentioned outer diameter difference in the roller axis direction is referred to as a left-right outer diameter difference.)
Therefore, a technology to make the outer diameter of the rubber roller symmetric by making the core metal speed profile asymmetric at a constant ratio (the speed change rate from one end to the center is different from the rate of change in the speed profile from the other end to the center). It has been proposed (see Patent Document 1).

  However, in the above prior art, in order to obtain a bilaterally symmetric rubber roller, the core metal speed control profile is asymmetrical at a certain ratio. However, the ratio of asymmetry is appropriately adjusted each time depending on molding conditions and prescription of rubber raw materials. There is no mention of issues that must be met.

  Further, when the inventors made additional trials using a plurality of cross heads, it was found that there was a cross head capable of suppressing the difference between the left and right outer diameters in the axial direction of the rubber roller. However, when the long-time crown extrusion molding is continuously performed using the cross head, the crown shape of the rubber roller may vary. For example, in the charging roller, further improvement of the required accuracy of the rubber roller for higher image quality is desired, and the crown shape in the continuous extrusion molding for a long time is suppressed and the difference in the outer diameter of the rubber roller in the axial direction is suppressed. It is desirable to achieve both suppression of fluctuations.

JP 2008-52025 A

  An object of the present invention is to provide an elastic roller manufacturing apparatus suitable for manufacturing a crown shape in which the layer thickness profile of the rubber layer is symmetrical in the axial direction of the elastic roller whose core is covered with a rubber layer. It is providing the manufacturing method of the used elastic roller. A further object of the present invention is to provide an elastic roller manufacturing apparatus capable of obtaining a stable outer diameter of a rubber roller even during long-time continuous molding, and an elastic roller manufacturing method using the same.

An apparatus for manufacturing an elastic roller according to the present invention includes:
An apparatus used for manufacturing a cored bar and an elastic roller in which a peripheral surface of the cored bar is covered with a rubber elastic layer,
An extruder for extruding the rubber elastic layer forming material, and a crosshead connected to the tip of the extruder,
The crosshead
A tubular member having a through-hole through which the core bar passes;
Concentrically with the through hole, the cross head is arranged to surround the through hole by being partitioned by the inner peripheral surface of the crosshead and the outer peripheral surface of the tubular member, and one end communicates with the through hole. An annular flow path having an inlet for the rubber elastic layer forming material extruded from the extruder at the other end,
The annular flow path has an annular region on its wall surface that is concentric with the through-hole and includes iron nitride so that the adhesion of the material is enhanced compared to other regions. An elastic roller manufacturing apparatus characterized by the above.

A method for producing an elastic roller according to the present invention is a method for producing an elastic roller in which a core metal and an outer peripheral surface of the core metal are covered with a rubber elastic layer, using the manufacturing apparatus configured as described above.
A metal core is supplied to the through hole of the crosshead, and the rubber elastic layer forming material is supplied to the annular flow path, and a coating layer of the rubber elastic layer forming material is provided on the outer peripheral surface of the metal core. Forming, and
And a step of curing the coating layer.

  The cross head of the elastic roller manufacturing apparatus according to the present invention has higher adhesion of a material for forming a rubber elastic layer on a part of the wall surface of the annular flow path provided in the cross head compared to other parts. Having an annular region formed. This suppresses a delay in responsiveness to the core metal speed control profile due to the viscoelasticity of the raw material for forming the rubber elastic layer and the material slip on the wall surface of the flow path. As a result, it is possible to manufacture an elastic roller that suppresses the difference between the left and right outer diameters of the crown shape without adjusting the core metal speed control profile asymmetrically. Furthermore, with such a cross head configuration, even in long-term continuous molding, fluctuations in the crown shape can be suppressed, and a large number of elastic rollers that maintain a good crown shape can be manufactured stably. In addition, fluctuations in the outer diameter can be suppressed even when forming a straight shape with a constant outer diameter of the elastic roller, and many elastic rollers that suppress fluctuations in the outer diameter of the straight shape can be stabilized even during long-term continuous molding. Can be manufactured.

It is explanatory drawing which showed typically the apparatus used for manufacture of the elastic roller of this invention. It is explanatory drawing which showed typically the cross section of the apparatus used for manufacture of the elastic roller of this invention. It is a figure which shows the example of the metal core governing profile in this invention. It is a figure which shows the elastic roller outer diameter of Example 1. FIG. It is a figure which shows the elastic roller outer diameter of the comparative example 1.

  Hereinafter, the present invention will be described in more detail with reference to the drawings. In the present invention, the term “crown shape” refers to a shape in which the outer diameter of the rubber elastic layer gradually increases from both ends in the axial direction of the cored bar toward the center, Includes a portion having a constant portion along the axial direction of the cored bar. The reverse crown shape refers to a shape (also referred to as a drum shape) in which the outer diameter of the rubber elastic layer is gradually reduced from the both ends in the axial direction of the cored bar toward the center.

  The elastic roller manufacturing apparatus according to the first aspect of the present invention will be described.

  FIG. 1 is an explanatory view schematically showing an apparatus used for manufacturing a cored bar according to the present invention and an elastic roller in which the outer peripheral surface of the cored bar is covered with a rubber elastic layer. As shown in FIG. 1, it has an extruder 1 for extruding the raw material of the rubber elastic layer, and a crosshead 2 connected to the tip of the extruder 1. A plurality of core bars 3 are supplied in series and continuously to the through holes 13 of the cross head 2 by the core bar feed roller 4 rotating in the direction of the arrow, and the supplied core bars sequentially pass through the through holes 13. pass. A material for forming a rubber elastic layer, for example, an unvulcanized rubber composition that has not been vulcanized, is supplied to the extruder 1 from the material charging port 6. The core bar 3 prepared in the core bar stocker 5 is continuously fed into the through hole 13 by the core bar feed roller 4 capable of adjusting the feed rate. The unvulcanized rubber composition, which is inserted into the crosshead 2 and passes through the through-hole 13 and simultaneously formed into a cylindrical shape at the same time, is integrally extruded to cover the outer periphery with a layer of the unvulcanized rubber composition. The cored bar 3 is obtained. It is preferable that the trailing end of the preceding core bar is fed so that the leading end of the subsequent core bar always abuts. That is, by always abutting the rear end of the preceding metal core and the front end of the subsequent metal core, the unvulcanized rubber composition does not enter between them, and the feed speed of the metal core 5 is stabilized and shaped. Is also stable. Since the core metal 3 is continuously supplied to the crosshead 2, the unvulcanized rubber layer continuously coated on the core metal 3 is connected to the joint between the rear end of the preceding core metal and the front end of the subsequent core metal. A take-off step 7 for cutting is performed. Further, after the vulcanization step (not shown), the elastic roller 8 is formed by cutting and removing the rubber layers at both ends at a regular scale.

  FIG. 2 is an explanatory view schematically showing a cross section of an apparatus used for manufacturing a cored bar according to the present invention and an elastic roller whose outer peripheral surface is covered with a rubber elastic layer. As shown in FIG. 2, the crosshead 2 includes a die 10, a nipple 9, and a through hole 13, which are preferably arranged in the vertical direction. The through-hole 13 extending linearly is formed as a hollow portion of the tubular member, and a nipple 9 is connected to the lower end of the tubular member, and the lower end opening is opened toward the discharge hole of the die 10. . With these components, one end communicates with the through hole 13 inside the cross head 2 so as to be concentric with the through hole 13 and surround the periphery of the through hole 13, and the other end is extruded by the screw 15 from the extruder 1. An annular channel 16 having an inlet for the rubber material to be produced is provided. In the present invention, the annular flow path is defined by defining the inner peripheral surface of the crosshead 2 (including the inner peripheral surface of the die 10), the outer peripheral surface inside the crosshead 2 of the tubular member 18, and the outer peripheral surface of the nipple 9 as wall surfaces. And an annular region concentric with the through hole 13. That is, it arrange | positions so that the circumference | surroundings of the tubular member 18 may be surrounded. This annular flow path becomes a flow path for the unvulcanized rubber composition supplied from the extruder 1, and each of the above surfaces constitutes a contact surface with the unvulcanized rubber composition. The unvulcanized rubber composition is extruded from a discharge hole (die nozzle) 14 at the tip of the die 10 and extruded as a cylindrical coating layer on the outer periphery of the core metal passing through the through hole 13.

  In the example of FIG. 2, the annular flow channel 16 has a nitriding portion 17 as an annular region forming a part of the wall surface. The nipple outer peripheral surface 11 and the die inner peripheral surface 12 correspond. These surfaces are formed as a continuous region surrounding the through hole 13 in an annular shape concentric with the through hole 13. The region including the iron nitride on the wall surface of the annular channel has higher adhesion to the unvulcanized rubber composition than the other regions.

  By providing an iron nitride portion having a higher adhesion to the unvulcanized rubber composition than other regions on a part of the wall surface of the annular flow path, a large number of core bars having a crown-shaped coating layer are formed. Even when continuous molding is performed for a long time, fluctuations in the crown shape between the cores can be suppressed, and stable production of the rubber roller is possible. This is because a change in the discharge amount due to the excessive adhesion of the rubber material on the wall surface of the annular flow path can be suppressed.

  In the conventional method, when the rubber elastic layer forming material is extruded into a crown shape having a different outer diameter in the axial direction of the rubber roller, the feed speed of the core bar continuously supplied to the through hole of the cross head, that is, the core The thickness of the rubber layer coated on the core metal is adjusted by accelerating / decelerating the gold governing profile. When the discharge amount of the extruder is constant, that is, when the screw rotation speed is constant, it is possible to vary the thickness of the rubber layer covered by the core metal by adjusting the acceleration / deceleration of the core metal feed at the discharge port. In a certain die nozzle portion, a periodic pressure fluctuation is caused for each cored bar. That is, the periodic pressure fluctuation generated at the discharge port propagates through the rubber material in the crosshead flow path toward the direction opposite to the extrusion discharge direction, that is, toward the extruder and the screw. Thus, when the pressure fluctuation generated at the discharge port is propagated to the extruder, the pressure of the rubber material in the cross head, that is, the extrusion pressure at the screw tip portion is changed. This fluctuation in the extrusion pressure causes a fluctuation in the amount of material charged into the screw. When the filling amount of the material into the screw fluctuates, as a result, the discharge amount of the extruder fluctuates. Since this series of pressure fluctuations propagates through the flow path in the crosshead through the material filled there, it is delayed from the period of pressure fluctuations that occur at the screw part and the period of pressure fluctuations that occur at the discharge port at the tip of the die. A phase difference will occur. The core metal speed control profile is set so that the desired crown shape of the rubber roller can be obtained on the premise that the discharge amount of the extruder is constant. When the pressure fluctuation phase difference described above occurs, the discharge amount of the extruder changes, and the change in the discharge amount becomes the rubber layer coating amount at a delayed period with respect to the originally intended change in the rubber layer coating amount. It will be added. As a result, the outer diameter of the rubber roller changes from the shape at the position.

  For this reason, in the case of crown extrusion molding, periodic pressure fluctuations generated at the discharge port propagate through the flow path in the crosshead through the material filled there, and the period of pressure fluctuations generated at the screw part and the discharge at the tip of the die. By causing a delay in the period of pressure fluctuations occurring at the outlet, the expected discharge amount is not achieved, so that the crown shape becomes an asymmetric elastic roller. Therefore, it has been found that an elastic roller having a symmetrical crown shape can be manufactured by attenuating and suppressing the propagation of periodic pressure fluctuations generated at the discharge port at the tip of the die.

  For the above reason, by nitriding a part of the annular channel wall surface in the cross head, the adhesion of the unvulcanized rubber material is enhanced on the annular channel wall surface, thereby suppressing the material slip at that part. . In other words, even when pressure fluctuations occur at the discharge port, if the slip of unvulcanized rubber material is suppressed on the wall surface of the annular flow path, the pressure fluctuations propagate when the pressure fluctuations propagate through the crosshead toward the screw. Can be attenuated and relaxed. Therefore, fluctuations in the extrusion pressure at the screw tip can be suppressed, and as a result, fluctuations in the discharge of the extruder are suppressed, so that a desired rubber roller shape can be formed.

  Further, as a range for performing the nitriding treatment, it is preferable that a part of the wall surface of the annular flow path 16 excluding the die nozzle 14 is subjected to nitriding treatment concentrically with the through hole 13. In the present invention, the reason why a part of the wall surface of the annular flow channel is nitrided annularly is to improve the adhesion of the material on the wall surface of the annular flow channel uniformly in the circumferential direction around the central axis of the through hole. . In other words, by performing nitriding in an annular shape, even if pressure fluctuation occurs at the discharge port at the tip of the die, if material slippage is suppressed on the wall surface of the annular flow channel that has undergone nitriding treatment, the pressure fluctuation is applied to the screw in the crosshead. When propagating in the direction of pressure, the propagation of pressure fluctuations can be attenuated and mitigated. Therefore, by changing the discharge amount due to pressure fluctuation at the discharge port at the tip of the die uniformly in the circumferential direction of the annular flow path by the annularly nitrided wall surface, the rubber layer thickness in the circumferential direction of the rubber roller is made uniform. can do. In order to enhance the effect of the present invention, as shown in FIG. 2, both the inner wall surface around the through hole 13 including the nipple outer peripheral surface 11 and the outer wall surface including the inner peripheral surface of the die of the annular flow path 16 are provided. Is preferably subjected to nitriding treatment. Only one of the inner wall surface and the outer wall surface of the annular flow path 16 may be subjected to nitriding treatment. However, in order to further enhance the effect of suppressing fluctuations in the discharge amount, both of these wall surfaces are subjected to nitriding treatment. Is more preferable.

  The position and range where the nitriding treatment is performed only on a part of the wall surface of the annular flow path 16 excluding the inner peripheral surface of the die nozzle 14 is not particularly limited as long as it is a position and range where the effect of suppressing fluctuations in the discharge amount can be obtained. Furthermore, in the present invention, the annular flow path includes not only a cylindrical or circular flow path but also a tapered flow path. The core metal and the unvulcanized rubber composition are merged, and the outer peripheral surface of the nipple 9 near the region where the coating layer is formed on the core metal and the inner peripheral surface of the die 10 excluding the die nozzle 14 are nitrided. It is more preferable. That is, the nipple outer peripheral surface 11 and the die inner peripheral surface 12 shown in FIG. This is because the propagation of the pressure fluctuation toward the screw in the annular flow path 16 is easily attenuated by attenuating the propagation of the pressure fluctuation in the vicinity of the discharge port, which is the place where the pressure fluctuation occurs. Also, depending on the material prescription as the range for nitriding treatment, if the adhesion of the material becomes too high and the surface of the coating layer to be molded becomes rough, the inner peripheral surface of the die nozzle may be removed from the nitriding region. preferable. In the present invention, only a part of the wall surface of the annular flow path 16 excluding the die nozzle 14 is subjected to nitriding treatment because the adhesion of the unvulcanized rubber raw material becomes too high when long-time extrusion molding is continuously performed, This is because fluctuations in the rubber discharge amount may occur. It is presumed that the film thickness and crown shape of the elastic roller fluctuate due to the fluctuation of the discharge amount. For the reasons described above, the region where the nitriding treatment is performed can be appropriately adjusted according to the molding conditions and the rubber material prescription.

  As a nitriding method applicable to the present invention, various known nitriding methods such as gas nitriding, plasma nitriding, ion nitriding, gas soft nitriding, salt bath soft nitriding, and sulfur nitriding can be applied. Nitriding may cause whitening or surface roughness of the metal surface due to the compound layer on the surface. However, when surface whitening or roughness becomes a problem, surface polishing may be performed. Since the adhesion with the material for forming the rubber elastic layer is enhanced by nitriding treatment, it is more preferable to use the material without removing whitening or surface roughness of the metal surface. The reason why the adhesion with the material for forming the rubber elastic layer is increased by the nitriding treatment is that the present inventors are attached by a chemical or physical action between the compound layer containing iron nitride and the rubber material. I suspect that this is because of the increased nature. In the present invention, the adhesion of the material is enhanced by forming a surface containing iron nitride using nitriding, but other surface treatments can be applied as long as the adhesion of the material can be enhanced. .

The nitriding treatment is a chemical surface hardening method of surface hardening heat treatment, which is a treatment that combines with various metal elements to form a hard nitride to harden the surface. A general purpose of nitriding is to improve wear resistance, fatigue resistance, corrosion resistance, and heat resistance. For example, the gas nitriding method is generally performed as follows. The object to be treated is put in an electric furnace, and ammonia gas (NH ₃ ) is introduced into the atmosphere and heated to 500 to 550 ° C. Atomic nitrogen (N) dissociated from ammonia gas diffuses and penetrates from the surface of the steel. Therefore, when the adhesion of the material for forming the rubber elastic layer is improved by nitriding, it is preferable that the wall surface of the annular channel is made of a metal material that can obtain the intended effect by nitriding. Furthermore, elements such as chromium (Cr), molybdenum (Mo), aluminum (Al), etc. existing in the steel are combined with nitrogen to form a nitrided layer (hardened iron nitride layer) made of hard nitride. Therefore, as a metal material suitable for the gas nitriding treatment, a metal material containing iron, for example, steel can be used. Among them, an alloy steel containing at least one of Cr, Mo and Al is preferable. In ion nitriding, most steel types can be processed. Therefore, in the present invention, when a region containing iron nitride is formed by performing nitriding on at least the annular flow path, the material that can be used as the crosshead 2 is a steel material using iron as a base material, and hardening of the iron nitride. In order to form a layer, it is preferable that the layer is appropriately selected according to the nitriding method.

  As a method of partially nitriding, nitriding may be performed only on a part of the annular flow path by masking. Or it is good also as a method which makes it the structure which can divide | cross the crosshead which comprises an annular flow path, and performs nitriding separately with respect to the divided | segmented parts.

  As a surface treatment method for obtaining a wall region in which the adhesion of the material for forming the rubber elastic layer is relatively lowered, compared to the region in which the adhesion of the material for forming the rubber elastic layer is enhanced by the nitriding treatment described above. Various known low friction surface treatments such as plating (electroplating, chemical plating, displacement plating, etc.), ceramic coating (PVD, CVD, etc.), fluororesin coating, diamond-like carbon, etc. can be applied. One or more surfaces selected from surfaces that have been surface-treated by these various methods can constitute a wall surface that has a relatively low adhesion of the material for forming the rubber elastic layer.

  As the plating treatment, for example, hard chrome plating, treatment containing fluorine resin in the plating, or the like can be applied. Nickel plating is not preferable because it reacts with sulfur contained in the rubber material. Examples of the ceramic coating include TiN, TiC, and the like. It is preferable to appropriately select the surface treatment according to various compounding agents blended in the material for forming the rubber elastic layer. The surface treatment is not particularly limited to the above-described surface treatment, as long as the surface treatment is less adhesive to the material for forming the rubber elastic layer than the nitriding treatment described above, and can be appropriately selected.

  Also, even if the surface roughness of the annular flow path is increased in order to enhance the adhesion of the material for forming the rubber elastic layer, the difference between the left and right outer diameters of the crown shape having different outer diameters in the axial direction of the rubber roller and the variation of the crown shape As a result, no significant effect was observed. Therefore, the surface roughness of the wall surface of the annular channel subjected to the nitriding treatment in the present invention is not particularly limited, but the surface roughness (Ra) is suitably about 0.05 μm to 1.6 μm according to JIS1994. is there. If the surface roughness is too large, the rubber roller surface roughness after molding will increase. Moreover, even if it is too small, the surface roughness of the rubber roller does not become small for the labor of the surface processing process of the wall surface of the annular flow path.

  Next, a process of forming coating layers having partially different thicknesses on the outer periphery of the core metal using the manufacturing apparatus according to the present invention will be described. For each of the core bars 5 continuously supplied to the cross head 2, the adjustment of the layer thickness of the coating layer provided on the outer periphery of the core bar is performed by adjusting the feed speed of the core bar 5 to the cross head 2 or forming a rubber elastic layer around the core. This can be done by changing the take-up speed of the cored bar 5 coated with the material.

  The amount of the rubber elastic layer forming material coated on the core metal 3 by the crosshead 2 (the thickness of the coating layer) is inversely proportional to the moving speed of the core metal when the supply amount of the rubber elastic layer forming material is constant. To do. That is, when the moving speed of the core metal in the die nozzle 14 as the discharge port of the crosshead 2 is faster than the discharge speed of the material for forming the rubber elastic layer that passes through the die nozzle, the thickness of the coating layer is die-swelled. It becomes thinner than the thickness. This is because the rubber elastic layer forming material extruded in a cylindrical shape by the cross head moves while being covered around the core bar while being stretched. That is, the thickness of the coating layer can be adjusted to be thicker or thinner by adjusting the moving speed of the cored bar. The core bar movement speed is to change the feed speed of the core bar to the die nozzle, that is, the feed speed of the core bar to the cross head, or the take-up speed of the core bar with the coating layer formed on the outer periphery. Can be adjusted.

  When the core elastic member 3 is coated with the rubber elastic layer forming material in a cylindrical shape by using the crosshead 2 in this manner, the amount of extrusion of the rubber elastic layer forming material is constant, and the moving speed of the metal core 3 is set to the core metal 3. Change in the axial direction of the gold 3. Thereby, an elastic roller in which the layer thickness of the coating layer, that is, the cylindrical outer diameter is changed along the axial direction can be manufactured. By changing the moving speed of the core metal 3 depending on the axial position of the core metal, an elastic roller having an outer diameter profile formed in a crown shape, an inverted crown shape, a tapered shape, a trapezoidal shape, or the like is obtained. The feeding speed of the cored bar 3 is controlled by feeding means (for example, the cored bar feeding roller 4) in which predetermined speeds of respective parts extending over one end, the center, and the other end of the cored bar 3 are programmed in advance. Can do. Further, the take-up speed of the core bar can be similarly controlled by a take-up means programmed with a predetermined speed of each part over one end part, the central part, and the other end part of the core bar 3. For example, FIG. 3 shows an example of the feeding speed of the core metal to the cross head when the elastic roller having a crown shape is produced by changing the feeding speed of the core metal 3. The horizontal axis indicates the axial direction of the cored bar, and the vertical axis indicates the feed rate [mm / s] of the cored bar. As can be seen from FIG. 3, in the case of a crown-shaped rubber roller having a small outer diameter at the end portion and a large outer diameter at the central portion, the moving speed of the cored bar is increased at one end of the cored bar to reach the central part. The speed is gradually reduced according to the above, and the speed is gradually increased from the center to the other end. Thus, the film thickness of the unvulcanized rubber composition to be coated is thin at both ends and thick at the center, and a so-called crown-shaped rubber roller can be manufactured.

  In the above example, the case where the discharge speed of the material for forming the rubber elastic layer is constant and the moving speed of the core metal 3 is changed has been described. Alternatively, the thickness of the rubber layer coated around the core metal 3 can be adjusted by changing the discharge rate of the material for forming the rubber elastic layer from the cross head 2 while keeping the moving speed of the core metal 3 constant. You can also. Furthermore, in order to obtain a desired shape, it may be combined with a case where the feed rate or the take-up rate is changed.

  The material used as the core metal 3 of the elastic roller is preferably a stainless steel rod, a phosphor bronze rod, an aluminum rod, or the like including a steel material such as nickel-plated or chrome-plated SUM material, but is not particularly limited thereto. .

  Examples of rubber materials used for the rubber elastic layer forming material used in the present invention include natural rubber, epicrawler hydrin rubber, butadiene rubber, styrene-butadiene rubber (SBR), nitrile rubber, nitrile butadiene rubber (NBR), and ethylene. -Propylene rubber (EPDM), butyl rubber, chloroprene rubber (CR), silicone rubber, urethane rubber, fluorine rubber, chlorine rubber, thermoplastic elastomer and the like. Any of these may be used alone or in a blended form.

  Moreover, the electroconductivity can be made into a predetermined value by using a conductive agent suitably with respect to a rubber material. The electrical resistance of the rubber roller can be adjusted by appropriately selecting the type and amount of the conductive agent. Examples of conductive particles dispersed as a conductive agent in the rubber material include ketjen black EC, acetylene black, carbon for rubber, carbon for color (ink) subjected to oxidation treatment, and conductive carbon such as pyrolytic carbon. Can be used. Specific examples of carbon for rubber include Super Abrasion Furnace (SAF: Super Abrasion Resistance), Intermediate Super Abrasion Furnace (ISAF: Quasi Super Abrasion Resistance), High Abrasion Furnace (HAF: High Abrasion E), Furnace (FEF: good extrudability), General Purpose Furnace (GPF: general purpose), Semi Rein Forcing Furnace (SRF: medium reinforcing), Fine Thermal (FT: fine particle thermal decomposition) and Medium Thermal MT (medium thermal decomposition) ) And the like.

Also, graphite such as natural graphite and artificial graphite can be used. In addition, gold oxide such as TiO ₂ , SnO ₂ , ZnO, solid solution of SnO ₂ and Sb ₂ O ₃ , double oxide such as solid solution of ZnO and Al ₂ O ₃ , metal powder such as Cu, Ag, etc. Various known materials can be used, and these may be used alone or in a blend of a plurality of types. Moreover, you may provide electroconductivity using a conductive polymer, an ionic conductive agent, etc. together with the said electroconductive particle. In addition, an inorganic or organic filler or a crosslinking agent may be added to the rubber material. Examples of the filler include silica (white carbon), calcium carbonate, magnesium carbonate, clay, talc, zeolite, alumina, barium sulfate, and aluminum sulfate. Examples of the crosslinking agent include sulfur, peroxide, crosslinking aid, crosslinking accelerator, crosslinking acceleration aid, crosslinking retarder and the like. Furthermore, a plasticizer, an anti-aging agent, an antistatic agent, an ultraviolet absorber, a reinforcing agent, a filler, a lubricant, a mold release agent, a pigment, a dye, a flame retardant, and the like can be appropriately added as necessary.

  In the case of obtaining a rubber elastic layer by curing to a desired hardness by vulcanization, an unvulcanized rubber material that has not been vulcanized and an additive that is blended as necessary A vulcanized composition is used.

  The method for producing the elastic roller of the present invention described above will be described in more detail by way of examples and comparative examples using rubber rollers as examples, but these do not limit the present invention in any way.

[Example 1] The composition of the unvulcanized rubber composition used is shown below.
<Preparation of unvulcanized rubber composition 1>
・ For 100 parts by mass of NBR (trade name: “JSR N230SV”, manufactured by JSR),
48 parts by mass of carbon black (trade name: “Toka Black # 7360SB”, manufactured by Tokai Carbon Co., Ltd., DBP oil absorption 87)
-1 part by weight of zinc stearate,
・ 5 parts by mass of zinc oxide (trade name: “Zinc oxide type 2”, manufactured by Shodo Chemical Co., Ltd.) ・ 20 parts by mass of calcium carbonate (trade name: “Nanox # 30”, manufactured by Maruo Calcium Co., Ltd.) with a pressure kneader Kneaded for 15 minutes, and further ・ Dibenzothiazolyl disulfide (trade name: “Noxeller DM-P”, manufactured by Ouchi Shinsei Chemical Co., Ltd.) 1 part by mass • Tetrabenzylthiuram disulfide (trade name: “Noxeller TBZTD”, Ouchi 4.5 parts by mass and 1.2 parts by mass of sulfur (vulcanizing agent) were added and kneaded with an open roller for 15 minutes to prepare an unvulcanized rubber composition 1. Thereafter, this unvulcanized rubber composition 1 was used unless otherwise specified.

<Production of rubber roller>
A core metal of SUM24, which is a general-purpose free-cutting steel having an outer diameter of φ6 mm and a length of 240 mm excluding both ends 12 mm and coated with an adhesive, was prepared. The adhesive used was an electrically conductive hot melt type. As an extrusion molding apparatus having a crosshead, an apparatus having the configuration shown in FIG. 1 was used. General-purpose rubber extruder (trade name: “extruder with vent”, manufactured by Mitsuba Seisakusho; screw diameter 45 mm, L / D = 20 extruder, L is screw length, D is screw diameter) The temperature during extrusion was adjusted to a head temperature of 90 ° C, a cylinder temperature of 90 ° C, and a screw temperature of 90 ° C. The discharge speed of the unvulcanized rubber composition by the extruder 1 (FIG. 1) (the amount of extrusion per unit time) is set so that the screw speed of the extruder is 10.5 rpm so that the outer diameter of the predetermined elastic roller is obtained. did. In order to form the outer diameter profile of the rubber layer coated around the cored bar into a crown shape, the moving speed of one cored bar was set as shown in FIG. The feed rate of the cored bar in one cored bar is changed, and each position (part) of the cored bar represents the speed (moving speed) at which the rubber material is coated and extruded from the die 10.

  At the end of the core 1 (0 mm position), the feed rate of the core is 52.1 mm / s, and the feed rate is gradually decreased from this end toward the center of the core 1 to reduce the center. In the part (core metal position: 125 mm), the feed rate was 44.2 mm / s. The feed rate was gradually increased from the center toward the other end (position of 240 mm) to a feed rate of 52.1 mm / s. The feed rate of the cored bar was periodically given to each cored bar inserted into the crosshead continuously by the cored bar feed roller. In about 8 hours, 5000 rubber rollers were continuously extruded. At this time, molding was continuously performed while changing the number of rotations of the screw so that the central outer diameter in the axial direction of the rubber roller became a desired outer diameter. The outer diameter profile was controlled by the core feed speed.

  Chromium molybdenum steel (SCM435) was used as the material for the crosshead, die and nipple. The tip diameter of the nipple was 8 mm. The inner diameter of the die nozzle 14 was set to φ9.0 mm. The nitriding treatment range of the nipple 9 was subjected to a surface treatment over the entire circumference in the circumferential direction concentric with the through-hole 13 in an annular shape up to the flow path length of 53 mm on the nipple outer peripheral surface 11 contacting the unvulcanized rubber composition from the tip of the nipple 9 . In the nitriding treatment range of the die 10, the entire surface of the die inner peripheral surface 12 that is in contact with the unvulcanized rubber composition upstream from the position of the die nozzle 14 was subjected to surface treatment in an annular shape up to a flow path length of 51 mm. The wall surfaces of the die nozzle 14 and other annular channels 16 were subjected to hard chrome plating (HCr). The plating film thickness was about 30 μm. Gas nitriding was used as the nitriding method. By this nitriding treatment, a hardened layer containing iron nitride of about 35 μm in the depth direction from the surfaces of the nipple outer peripheral surface 11 and the die inner peripheral surface 12 was formed. Further, the surface roughness (Ra) of the nipple outer peripheral surface 11 and the die inner peripheral surface 12 after the nitriding treatment was 0.44 μm according to JIS1994.

  The rubber elastic layer at both ends of the molded unvulcanized rubber roller is cut by 10 mm, the axial width of the rubber elastic layer portion is set to 220 mm, and then heat vulcanized at 160 ° C. for 50 minutes in an electric furnace. Obtained.

<Measurement of elastic roller outer diameter>
The outer diameter of the rubber elastic layer portion of the obtained rubber roller was measured at 5000 mm at a pitch of 5 mm at 220 mm excluding both ends 10 mm in the axial direction. The measurement result of the rubber roller outer diameter obtained by averaging the outer diameters at each measurement point is shown in FIG. In FIG. 4, the horizontal axis represents the position of the rubber roller in the elastic layer axial direction, and the vertical axis represents the outer diameter. At this time, the outer diameter of the end portion (5 mm position) of the rubber roller was about 8.53 mm. The outer diameter of the rubber roller gradually increased toward the center, and was about 8.70 mm at the center (110 mm position). The outer diameter of the rubber roller gradually decreased from the central portion toward the other end (position 215 mm), and the outer diameter was about 8.53 mm. A crown shape was formed. In FIG. 4, the solid line indicates the outer diameter of the rubber roller, and the broken line indicates the outer diameter of the rubber roller reversed at the center. The difference between the outer diameters of the solid line and the broken line indicates the degree of deviation of the rubber roller outer diameter. The difference between the measured outer diameters at both ends was calculated for 5000 rollers as a left-right shift. At this time, the left-right difference average, which is the average value of the 5000 left-right deviations, was 8 μm, and the maximum left-right difference was 16 μm. At this time, the crown amount (central outer diameter—average diameter at both ends) was about 136 μm. The variation in the crown amount of the 5000 rubber rollers was about 19 μm. As the outer diameter measuring instrument, LS-7500 (controller) and LS-7030M (measurement unit) manufactured by Keyence Corporation were used. The results are shown in Table 1.

[Evaluation of charging roller image]
Among the 5000 rollers described above, a roller having the lowest shape accuracy, that is, a rubber roller having a maximum difference in outer diameter (right and left difference) at both ends was used as the charging roller 1 in the following tests. In this example, the roller has a left / right difference of 16 μm.

The rubber roller is installed with an ultraviolet lamp having a wavelength of about 250 nm in parallel with the roller axial direction, and the ultraviolet light having a wavelength of 254 nm is rotated for 2 minutes while rotating the roller in the circumferential direction so that the integrated light quantity becomes 9000 mJ / cm ^2. Irradiation was performed to form an ultraviolet treatment layer on the surface, and the charging roller 1 was obtained. A low pressure mercury lamp (trade name: “QLC500”, manufactured by Harrison Toshiba Lighting Co., Ltd.) was used for ultraviolet irradiation.

  A color laser printer (trade name: “HP Color LaserJet 4700dn”, manufactured by Hewlett-Packard Company), which is an electrophotographic apparatus, and a process cartridge for the printer were used. This printer was used by modifying it so that it can output a recording medium at 200 mm / sec (A4 vertical output). The primary charging output is a DC voltage (Vdc) of −1100V. The resolution of the image is 600 dpi. The charging roller was removed from the process cartridge, and the charging roller 1 was set. The charging roller 1 was brought into contact with the electrophotographic photosensitive member by a pressing force of a spring of 4.9 N at one end and a total of 9.8 N at both ends.

The process cartridge on which the charging roller 1 was set was left in a 23 ° C./50% RH environment for 24 hours, and then an initial image evaluation was performed in that environment. Specifically, a halftone image (an image in which a horizontal line having a width of 1 dot and an interval of 2 dots was drawn in the direction perpendicular to the rotation direction of the electrophotographic photosensitive member) was output and evaluated. In the evaluation, the obtained halftone image was visually observed, and the density unevenness image due to the contamination of the charging roller surface caused by the shape of the charging roller 1 described above was determined according to the following criteria.
Rank A: Density unevenness image does not occur.
Rank B: Only a slight density unevenness image is recognized.
Rank C: A dark image part can be confirmed by the pitch of the charging roller, but there is no problem in practical image.
Rank D: Density unevenness image is conspicuous and deterioration of image quality is recognized.

After the initial image evaluation, a durable image evaluation was performed. Specifically, a two-sheet intermittent endurance test (endurance after stopping the rotation of the printer for 3 seconds for every two sheets) was performed on a 1% print density image at a process speed of 200 mm / sec. The number of printed sheets was 30000. A halftone image was then output and evaluated. The evaluation is performed by visually observing the halftone image obtained in the same manner as in the initial image evaluation, and the density unevenness image due to the stain on the surface of the charging roller caused by the shape of the charging roller 1 described above is the same standard. Judged by.
In the charging roller 1 of this example, a density unevenness image did not occur and a good image was obtained. The results are shown in Table 1.

[Example 2]
The rubber raw material in Example 1 was changed from NBR to SBR (trade name: “Toughden 2003”, manufactured by Asahi Kasei Chemicals Corporation), the amount of carbon black was changed to 50 parts by mass, and an unvulcanized rubber composition 2 was obtained. Produced. Using the unvulcanized rubber composition 2, the surface treatment of the flow passage wall surface constituting the annular flow passage 16 other than the die nozzle 14 and the nitriding region is performed by TiN ceramic coating (film thickness 2 μm) by PVD (physical vapor deposition method). ). By adjusting the surface roughness before the surface treatment, the surface roughness (Ra: JIS 1994) after the surface treatment of the nipple outer peripheral surface 11 and the die inner peripheral surface 12 was set to 0.25 μm. Table 1 shows the results of creating and evaluating a charging roller in the same manner as in Example 1 except for these conditions. The setting of the surface roughness after the surface treatment by adjusting the surface roughness before the surface treatment is the same in the following examples.

Example 3
The unvulcanized rubber composition 1 in Example 1 was changed from NBR to epichlorohydrin rubber (trade name: “Epichromer CG102”, manufactured by Daiso Corporation). The carbon black was changed to 5 parts by mass (trade name: “HTC # 20”, manufactured by Nippon Nihon Carbon Co., Ltd.). Tetrabenzylthiuram disulfide (trade name: “Noxeller TBZTD”, manufactured by Ouchi Shinsei Chemical Co., Ltd.) 4.5 parts by mass tetramethylthiuram monosulfide (trade name: “Noxeller TS”, manufactured by Ouchi Shinsei Chemical Co., Ltd.) 0.5 Changed to parts by mass. Using these raw materials, an unvulcanized rubber composition 3 was produced in the same manner as in Example 1. Using the unvulcanized rubber composition 3, the surface treatment of the flow passage wall surface constituting the annular flow passage 16 other than the die nozzle 14 and the nitriding region is made of fluororesin coating (Teflon (registered trademark) coating), film thickness The thickness was 25 μm. The surface roughness (Ra: JIS 1994) after the surface treatment of the nipple outer peripheral surface 11 and the die inner peripheral surface 12 was set to 0.33 μm. Table 1 shows the results of creating and evaluating a charging roller in the same manner as in Example 1 except for these conditions.
Example 4
In Example 1, the surface treatment of the flow channel wall surface constituting the annular flow channel 16 other than the die nozzle 14 and the region subjected to nitriding treatment was performed with a diamond-like carbon treatment (DLC treatment) with a film thickness of 1 μm by plasma CVD. The surface roughness after the surface treatment of the nipple outer peripheral surface 11 and the die inner peripheral surface 12 (Ra: JIS 1994) was 0.29 μm. Table 1 shows the results of creating and evaluating a charging roller in the same manner as in Example 1 except for these conditions.
Example 5
In Example 1, the surface treatment of the nipple was hard chrome plating (HCr) by electroplating to a film thickness of 35 μm. The surface roughness (Ra: JIS 1994) after the surface treatment of the nipple outer peripheral surface 11 and the die inner peripheral surface 12 was set to 0.37 μm. Table 1 shows the results of creating and evaluating a charging roller in the same manner as in Example 1 except for these conditions.
Example 6
In Example 1, the surface treatment of the die was hard chrome plating. The surface roughness (Ra: JIS 1994) after the surface treatment of the nipple outer peripheral surface 11 and the die inner peripheral surface 12 was 0.20 μm. Table 1 shows the results of creating and evaluating a charging roller in the same manner as in Example 1 except for these conditions.
Example 7
In Example 1, the range of nitriding treatment of the nipple outer peripheral surface 11 was set to a flow path length of 41 mm from the tip of the nipple 9 to the upstream side. The range of the nitriding treatment of the die part was set to a flow path length of 38 mm from the die nozzle position to the upstream side. Table 1 shows the results of the evaluation and evaluation of the charging roller in the same manner as in Example 1 except that the surface roughness after the surface treatment of the nipple outer peripheral surface 11 and the die inner peripheral surface 12 is Ra = 0.51 μm.
Example 8
Table 1 shows the results of evaluation and evaluation of a charging roller as in Example 1, except that the surface roughness after the surface treatment of the nipple outer peripheral surface 11 and the die inner peripheral surface 12 in Example 1 was set to Ra = 0.16 μm. Shown in
Example 9
Table 1 shows the results of evaluation and evaluation of a charging roller as in Example 1, except that the surface roughness after the surface treatment of the nipple outer peripheral surface 11 and the die inner peripheral surface 12 in Example 1 was set to Ra = 1.55 μm. Shown in
Example 10
In Example 1, the range of the nitriding treatment of the nipple outer peripheral surface 11 was set to a flow path length of 35 mm from the tip to the upstream side. The range of the nitriding treatment on the inner peripheral surface 12 of the die was set to a flow path length of 28 mm upstream from the position of the die nozzle 14. Table 1 shows the results of creating and evaluating a charging roller in the same manner as in Example 1 except that the surface roughness after the surface treatment of the nipple outer peripheral surface 11 and the die inner peripheral surface 12 was set to Ra = 0.05 μm.
Example 11
In Example 1, the surface treatment of the flow channel wall surface constituting the annular flow channel 16 other than the die nozzle 14 and the region subjected to nitriding treatment was PEEK (registered trademark) resin coat and the film thickness was 43 μm. The surface roughness (Ra: JIS 1994) after the surface treatment of the nipple outer peripheral surface 11 and the die inner peripheral surface 12 was set to 0.31 μm. Table 1 shows the results of creating and evaluating a charging roller in the same manner as in Example 1 except for these conditions.
[Comparative Example 1]
In Example 1, charging was performed in the same manner as in Example 1 except that the surface treatment of the die 10 and the nipple 9 was hard chrome plating, and the surface roughness of the nipple outer peripheral surface 11 and the die inner peripheral surface 12 was Ra = 0.13 μm. Table 1 shows the results of creating and evaluating the rollers. For reference, the outer diameter of the elastic roller measured in the same manner as in Example 1 is shown in FIG.

Example 12
In Example 1, the surface roughness of the nipple outer peripheral surface 11 and the die inner peripheral surface 12 was Ra = 0.47 μm. The feed rate of the cored bar was set to a constant feed rate of 42.2 mm / s in the length direction of the cored bar. The feed rate of the cored bar was continuously given to the cored bar inserted into the cross head by the cored bar feed roller. As a result, a rubber roller having a straight outer diameter in the axial direction was formed. In about 8 hours, 5000 rubber rollers were continuously extruded. At this time, molding was continuously performed while changing the number of rotations of the screw so that the central outer diameter in the axial direction of the rubber roller became a desired outer diameter. Except for the above, the elastic roller was molded using the same unvulcanized rubber composition 1, extruder, molding conditions and the like as in Example 1. Using the same outer diameter measuring instrument as in Example 1, the outer diameter of the 5000 rubber rollers was measured at a 5 mm pitch at 220 mm excluding 10 mm at both ends in the axial direction. The maximum value-minimum value of the outer diameter at all measurement points of the 5000 rubber rollers was 52 μm. The measurement results are shown in Table 2.
[Comparative Example 2]
In Example 11, the surface treatment of the flow channel wall surface constituting the annular flow channel 16 other than the die nozzle 14 and the region subjected to nitriding treatment was the same nitriding treatment as that of the nipple outer peripheral surface 11 and the die inner peripheral surface 12. Table 2 shows the results of creating and evaluating an elastic roller in the same manner as in Example 11 except that the surface roughness of the nipple outer peripheral surface 11 and the die inner peripheral surface 12 is Ra = 0.31 μm.

  As is apparent from Table 1, in Comparative Example 1, the surface treatment of the die and nipple is hard chrome plating. For this reason, the adhesion of the unvulcanized rubber composition is low, and the left / right difference average and the left / right difference maximum in which the right and left deviation of the outer diameter is the average value and the maximum value are relatively large compared to Examples 1-10 Yes. For this reason, in the image evaluation, density unevenness occurred in the vicinity of the edge of the A4 vertical image. This seems to be due to uneven contact due to the difference between the left and right outer diameters of the rubber roller. In Comparative Example 2, all annular channels including dies, nipples, and other channels are nitrided. Therefore, the occurrence of left / right deviation of the outer diameter is small. However, as a result of continuous extrusion molding of 5000 rubber rollers in about 8 hours, a variation in the crown amount of 73 μm occurred. Since all the channels are nitrided, the adhesion of the unvulcanized rubber composition on the channel wall surface becomes too high, resulting in an unstable discharge rate of the unvulcanized rubber composition. Yes. For this reason, in the image evaluation, density unevenness occurred in the vicinity of the center of the A4 vertical image. This seems to be because the crown shape of the rubber roller is not appropriate and contact unevenness occurs. This is because if the crown amount is too large, the end contact pressure decreases, and conversely if it is too small, the contact pressure decreases at the central portion.

  On the other hand, in Examples 1 to 11, which are the scope of the present invention, the left and right deviation of the outer diameter was 29 μm or less at the maximum value. At this time, the variation of the crown amount was 30 μm or less in the long-time continuous molding. In the image evaluation, density unevenness did not occur. Therefore, a roller shape having no practical problem is obtained.

  Further, as apparent from Table 2, in Comparative Example 2, even when the elastic roller is formed in the straight shape, the outer diameter fluctuation is larger than that in Example 11. Since all the flow paths are nitrided, the adhesion of the unvulcanized rubber composition on the flow path wall surface becomes too high, resulting in an unstable discharge amount of the unvulcanized rubber composition. It is because it is closed. Such a straight elastic roller can be used by polishing the elastic layer and processing it into a crown shape according to the application.

1: Extruder 2: Crosshead 3, 5: Metal core 13: Through hole 4: Metal core feed roller 6: Material inlet 5: Metal core stocker 8: Elastic roller 10: Die 9: Nipple 15: Screw 16: Annular Channel 18: Tubular member 14: Discharge hole (die nozzle)
17: Nitriding part 11: Nipple outer peripheral surface 12: Die inner peripheral surface

Claims (4)

An apparatus used for manufacturing a cored bar and an elastic roller in which a peripheral surface of the cored bar is covered with a rubber elastic layer,
An extruder for extruding the rubber elastic layer forming material, and a crosshead connected to the tip of the extruder,
The crosshead
A tubular member having a through-hole through which the core bar passes;
Concentrically with the through hole, the cross head is arranged to surround the through hole by being partitioned by the inner peripheral surface of the crosshead and the outer peripheral surface of the tubular member, and one end communicates with the through hole. An annular flow path having an inlet for the rubber elastic layer forming material extruded from the extruder at the other end,
The annular flow path has an annular region on its wall surface that is concentric with the through-hole and includes iron nitride so that the adhesion of the material is enhanced compared to other regions. An apparatus for manufacturing an elastic roller.   The region other than the region containing iron nitride is one or more surfaces selected from a plated surface, a surface coated with ceramic, a surface coated with fluororesin, and a surface coated with diamond-like carbon. The manufacturing apparatus according to claim 1, wherein the manufacturing apparatus is configured. A manufacturing method of an elastic roller using the manufacturing apparatus according to claim 1 or 2, wherein an outer peripheral surface of the core metal and the core metal are covered with a rubber elastic layer,
A metal core is supplied to the through hole of the crosshead, and the rubber elastic layer forming material is supplied to the annular flow path, and a coating layer of the rubber elastic layer forming material is provided on the outer peripheral surface of the metal core. Forming, and
And a step of curing the coating layer.   4. The method for producing an elastic roller according to claim 3, further comprising the step of changing the supply speed of the cored bar to vary the thickness of the coating layer in the axial direction of the cored bar.