Abstract:
The invention relates to molding of a roller in which a roller body is provided integrally on the outer periphery of an axial core member, and the objective of the invention is to prevent the generation of a thin burr, and damage to the die. In order to achieve this objective, a die is provided with a first split die and a second split die which can butt against one another or separate from one another at mutually-opposing parting surfaces. A roller body molding surface, a cavity being defined between the axial core member and the roller body molding surface when the mold is clamped; and recessed portions which are located at both end portions of the supporting portions and extend along the parting surfaces, and which are not in contact with the outer peripheral surface of the axial core member when the mold is clamped.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a U.S. National Stage Application of International Application No. PCT/JP2015/081427, filed on Nov. 9, 2015, and published in Japanese as WO 2016/092998 A1 on Jun. 16, 2016 and claims priority to Japanese Application No. 2014-248971, filed on Dec. 9, 2014. The entire disclosures of the above applications are incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
       [0002]    The present invention relates to a die for molding a roller used, for example, as an image forming roller, a pressurizing roller, or the like for a printer, a copying machine, or the like, with a structure in which a roller body made of a rubber-like elastic material (rubber material or synthetic resin material with rubber-like elasticity) is integrally molded on the outer periphery of an axial core member. 
       Description of the Conventional Art 
       [0003]    As illustrated in  FIG. 16 , a roller  100  used as an image forming roller or a pressurizing roller for a copying machine and the like, includes a structure in which a roller body  102  made of a rubber-like elastic material is integrally molded on the outer periphery of a metal axial core member  101  serving as a rotating shaft. 
         [0004]    A manufacturing method is known (for example, refer to Japanese Unexamined Patent Application Publication No. 1-135608A or Japanese Unexamined Patent Application Publication No. 2002-36247A described below) in which such a roller  100  is manufactured, as illustrated in  FIG. 17 , by manufacturing the axial core member  101 , positioning and fixing the axial core member  101  between a first split mold  201  and a second split mold  202  of a die  200  including the first split mold  201  and the second split mold  202  that can be contacted with and separated from each other, injecting uncrosslinked liquid rubber composition into a cylindrical cavity  203  defined between the axial core member  101  and roller molding surfaces  201   a ,  202   a  of the first split mold  201  and the second split mold  202  by mold clamping, and causing the liquid rubber composition to crosslink and cure, thereby integrating the rubber composition with the axial core member  101 . 
       SUMMARY OF THE INVENTION 
     Problem to be Solved by the Invention 
       [0005]    However, in the die  200  illustrated in  FIG. 17 , in a mold clamped state, a gap extending from the cavity  203  is present between supporting portions  201   b ,  202   b  respectively formed to the first split mold  201  and the second split mold  202 , and an outer circumferential surface of the end portion of the axial core member  101  supported by the supporting portions  201   b ,  202   b . This causes a thin burr  102   a  to be formed extending from an inner diameter part of the roller body  102  on the outer circumferential surface of the axial core member  101  of the molded roller  100 , as illustrated in  FIG. 18 . A trouble to a device may be caused if the thin burr  102   a  drops off from the outer circumferential surface of the axial core member  101  inside the device in which the roller  100  is incorporated. Hence, to prevent such a trouble, a step to deburr the thin burr  102   a  is necessary after the molding described above. 
         [0006]    If the outer circumferential surface of the end portion of the axial core member  101  is brought into press-contact with the supporting portions  201   b ,  202   b  in order to prevent such thin burrs  102   a  from being generated, as illustrated in  FIG. 19 , the axial core member  101  is deformed by the mold clamping load between the first split mold  201  and the second split mold  202 , and bitten between the parting surfaces of the first split mold  201  and the second split mold  202 , which forms protrusions  101   a ,  101   a . This obstructs the die  200  from being tightened and easily creates the gaps δ 1 , δ 2  between the parting surfaces. For this reason, as illustrated in  FIG. 20 , thin plate burrs  102   b ,  102   c  extending along the gaps δ 1 , δ 2  from the outer circumferential surface of the axial core member  101  and the outer circumferential surface of the roller body  102  are formed. As a result, not only a deburring step is still necessary, but also the die  200  may be damaged by repeatedly biting the axial core member  101 . 
         [0007]    The present invention has been made in view of the above points, and an object of the present invention is to prevent thin burrs from being generated and a die from being damaged, in molding a roller including a roller body integrally provided on the outer periphery of an axial core member. 
       Means for Solving the Problem 
       [0008]    As means for effectively solving the technical problem mentioned above, a die for molding a roller according to the invention defined in the first aspect includes a first split mold and a second split mold which are capable of contacting and separating on parting surfaces opposed to each other, and the first split mold and the second split mold are formed with: support portions capable of supporting an axial core member of the roller and closely contacting an outer circumferential surface of the axial core member at an appropriate surface pressure at the time of mold clamping; roller body molding surfaces that define a cavity between the axial core member and the roller body molding surfaces at the time of mold clamping; and recesses located at both end portions of each of the support portions and extending along the parting surfaces, not in contact with the outer circumferential surface of the axial core member at the time of mold clamping, and penetrating the supporting portions. 
         [0009]    In the above configuration, when the axial core member of the roller is positioned and disposed between the first split mold and the second split mold and mold clamped, the axial core member is supported in a close contact state between the support portions, and a cavity is defined between the axial core member and the roller body molding surfaces. At this time, a portion of the axial core member supported between the support portions of the first split mold and the second split mold is subject to compressive force due to mold clamping. However, since recesses are formed at both end portions of the support portions, the recesses extending along the parting surfaces of the first split mold and the second split mold, and are not in contact with the outer circumferential surface of the axial core member at the time of mold clamping, the outer circumferential surface of the axial core member is prevented from being bitten between the end portions of the support portions, so that the first split mold and the second split mold are not obstructed from being closed. Therefore, the parting surfaces of the first split mold and the second split mold are brought into close contact with each other. In the step of injecting the uncrosslinked liquid rubber composition into the cavity and crosslinking and curing the liquid rubber composition to integrally mold the roller body on the axial core member, since the support portions of the first split mold and the second split mold and the outer circumferential surface of the axial core member are in close contact with each other, the liquid rubber composition is prevented from permeating therebetween and forming the thin burr, and the liquid rubber composition is also prevented from permeating between the parting surfaces and forming the thin burr. 
         [0010]    The die for molding the roller according to the invention defined in the second aspect is that, in the configuration described in the first aspect, the first split mold and the second split mold are formed with tear-off portion molding surfaces located on the opposite side to the roller body molding surfaces interposing the support portions and that define a tear-off portion molding space between the axial core member and the tear-off portion molding surfaces at the time of mold clamping. 
         [0011]    In the above configuration, in the step of integrally molding the roller body on the axial core member, the uncrosslinked liquid rubber composition injected into the cavity defined between the axial core member and the roller body molding surfaces by mold clamping flows between the tear-off portion molding space defined between the axial core member and the tear-off portion molding surfaces and the cavity, through the recesses formed to the support portions therebetween as the gate. Hence, gate burrs continuous with the roller body are formed in the gate and the tear-off portion is formed in the tear-off portion molding space by curing the liquid rubber composition. This allows the gate burrs to be torn off together with the tear-off portion after the die is opened. 
         [0012]    The die for molding the roller according to the invention defined in the third aspect is that, in the configuration described in the first or second aspect, the axial core member is formed with an annular projection, and an outer circumferential surface of the annular projection is in close contact with the support portions in a state appropriately compressed in a radial direction. 
         [0013]    In the above-described configuration, the outer circumferential surface of the axial core member is made to closely contact the support portions of the first split mold and the second split mold in a state in which the annular projection is appropriately compressed in the radial direction, thereby enabling the close contact surface pressure to be heightened and permeation of the liquid rubber composition to be favorably sealed, and the load of the first split mold and the second split mold due to mold clamping to be reduced by compressive deformation of the annular projection. 
         [0014]    The die for molding the roller according to the invention defined in the fourth aspect is that, in the configuration described in the first or second aspect, each of the support portions is formed with an arc shape projection. 
         [0015]    In the above-described configuration, since the support portions formed in the first split mold and the second split mold are formed by arc shape projections, the range of contact with the axial core member is limited with respect to the axial direction, thereby enabling the close contact surface pressure to the axial core member to be heightened and permeation of the liquid rubber composition to be favorably sealed. 
       Effect of the Invention 
       [0016]    According to the die for molding of the roller of the present invention, in molding a roller including a roller body integrally provided on the outer periphery of an axial core member, the outer circumferential surface of the axial core member is prevented from being bitten between the parting surfaces of the first split mold and the second split mold at the time of mold clamping, a thin burr is prevented from being formed between the outer circumferential surface of the axial core member and the support portions of the first split mold and the second split mold, and between the parting surfaces, and damage to the first split mold and the second split mold due to biting or the like can be effectively prevented. 
     
    
     
       BRIEF EXPLANATION OF THE DRAWINGS 
         [0017]      FIG. 1  is a partial cross-sectional view illustrating a roller molded in a first embodiment of a die for molding a roller according to the present invention by cutting the roller at a plane passing through the axial center of the roller. 
           [0018]      FIG. 2  is a partial cross-sectional view in a separated state, illustrating the first embodiment of the die for molding the roller according to the present invention by cutting the roller at a plane passing through the axial center of a cavity. 
           [0019]      FIG. 3  is a partial cross-sectional view in the separated state, illustrating the first embodiment of the die for molding the roller according to the present invention by cutting the roller at a plane passing through line III-III in  FIG. 2  and orthogonal to the axial center of the cavity. 
           [0020]      FIG. 4  is a partial cross-sectional view in a mold clamped state, illustrating the first embodiment of the die for molding the roller according to the present invention by cutting the roller at a plane passing through the axial center of the cavity. 
           [0021]      FIG. 5  is a partial cross-sectional view in the mold clamped state, illustrating the first embodiment of the die for molding the roller according to the present invention by cutting the roller at a plane passing through line V-V in  FIG. 4  and orthogonal to the axial center of the cavity. 
           [0022]      FIG. 6  is a partial cross-sectional view illustrating a molded article in the first embodiment of the die for molding the roller according to the present invention by cutting the molded article at a plane passing through the axial center of the molded article. 
           [0023]      FIG. 7  is a cross-sectional view illustrating the molded article in the first embodiment of the die for molding the roller according to the present invention by cutting the molded article at a plane passing through line VII-VII in  FIG. 6  and orthogonal to the axial center of the molded article. 
           [0024]      FIG. 8  is an explanatory view illustrating a step of removing burrs from the molded article in the first embodiment of the die for molding the roller according to the present invention. 
           [0025]      FIG. 9  is a partial cross-sectional view in a separated state, illustrating a second embodiment of a die for molding a roller according to the present invention by cutting the roller at a plane passing through the axial center of a cavity. 
           [0026]      FIG. 10  is a partial cross-sectional view in the separated state, illustrating the second embodiment of the die for molding the roller according to the present invention by cutting the roller at a plane passing through line X-X in  FIG. 9  and orthogonal to the axial center of the cavity. 
           [0027]      FIG. 11  is a partial cross-sectional view in a mold clamped state, illustrating the second embodiment of the die for molding the roller according to the present invention by cutting the roller at a plane passing through the axial center of the cavity. 
           [0028]      FIG. 12  is a partial cross-sectional view in the mold clamped state, illustrating the second embodiment of the die for molding the roller according to the present invention by cutting the roller at a plane passing through line XII-XII in  FIG. 11  and orthogonal to the axial center of the cavity. 
           [0029]      FIG. 13  is a partial cross-sectional view illustrating a molded article in the second embodiment of the die for molding the roller according to the present invention by cutting the molded article at a plane passing through the axial center of the molded article. 
           [0030]      FIG. 14  is a cross-sectional view illustrating the molded article in the second embodiment of the die for molding the roller according to the present invention by cutting the molded article at a plane passing through line XIV-XIV in  FIG. 13  and orthogonal to the axial center of the molded article. 
           [0031]      FIG. 15  is an explanatory view illustrating a step of removing burrs from the molded article in the second embodiment of the die for molding the roller according to the present invention. 
           [0032]      FIG. 16  is a partial cross-sectional view illustrating the roller having a structure in which the roller body made of a rubber-like elastic material is integrally molded on the outer periphery of the axial core member, by cutting the roller at a plane passing through the axial center of the roller. 
           [0033]      FIG. 17  is a partial cross-sectional view in a mold clamped state, illustrating an example of a die for molding a roller in a conventional technique, by cutting the die at a plane passing through the axial center of a cavity. 
           [0034]      FIG. 18  is a partial cross-sectional view illustrating a molded article formed by the die for molding the roller in a conventional technique by cutting the molded article at a plane passing through the axial center of the molded article. 
           [0035]      FIG. 19  is a partial cross-sectional view illustrating a state in which a gap is created between parting surfaces in a conventional technique, by cutting at a plane orthogonal to the axial center. 
           [0036]      FIG. 20  is a partial cross-sectional view illustrating a state in which a thin burr is created due to the gap created between the parting surfaces in a conventional technique, by cutting at a plane orthogonal to the axial center. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0037]    Preferred embodiments of a die for molding a roller according to the present invention will be described hereinafter with reference to the drawings. Firstly,  FIGS. 1 to 8  illustrate a first embodiment. 
         [0038]      FIG. 1  illustrates a roller  300  which is molded using a die according to the first embodiment and is used as an image forming roller, a pressurizing roller, or the like in a printer, a copying machine, or the like, for example. The roller  300  has a structure in which a roller body  320  made of a rubber-like elastic material is integrally molded on the outer periphery of a metal axial core member  310  serving as a rotating shaft. An annular projection  311  located at one end in the axial direction of the roller body  320  is formed on an outer circumferential surface  310   a  of the axial core member  310 . 
         [0039]    As illustrated in  FIGS. 2 and 3 , the die according to the first embodiment for molding the above-described roller  300  includes a first split mold  1  and a second split mold  2  capable of contacting and separating on parting surfaces  1   a ,  2   a  opposed to each other. The parting surfaces  1   a ,  2   a  of the first split mold  1  and the second split mold  2  are provided with: support portions  11 ,  21  including arc shape protrusions and capable of closely contacting an outer circumferential surface  311   a  of the annular projection  311  of the axial core member  310 , at an appropriate surface pressure, in other words, with a proper interference at the time of mold clamping illustrated in  FIGS. 4 and 5 ; roller body molding surfaces  12 ,  22  which define a cylindrical cavity A between the axial core member  310  and the roller body molding surfaces at the time of mold clamping; and tear-off portion molding surfaces  13 ,  23  located on the opposite side in the axial direction to the roller body molding surfaces  12 ,  22  interposing the support portions  11 ,  21  and defining a tear-off portion molding space B between the one axial end  312  of the axial member  310  and the tear-off portion molding surfaces at the time of mold clamping, respectively. 
         [0040]    At both ends of each of the support portions  11 ,  21 , recesses  14 ,  24  are respectively formed, the recesses extending through the support portions  11 ,  21  in the axial direction along the parting surfaces  1   a ,  2   a , respectively, being not in contact with the outer circumferential surface  311   a  of the annular projection  311  of the axial core member  310  at the time of mold clamping, and defining semicircular gates C as illustrated in  FIG. 5  with the outer circumferential surface  311   a  of the annular projection  311 . 
         [0041]    Annular grooves  313 ,  314  are provided on both sides of the annular projection  311  in the axial core member  310  in the axial direction, in other words, the annular projection  311  is formed as a relative protrusion between the annular grooves  313 ,  314 . In addition, the annular projection  311  becomes narrower in width in the axial direction toward the outer diameter side so that the annular projection  311  is easily compressed and deformed when tightened between the support portions  11 ,  21  of the first split mold  1  and the second split mold  2 , and in width w 1  in the axial direction support portions  11 ,  21  and in width w 2  in the axial direction of the annular grooves  313 ,  314  are larger than in width w 3  in the axial direction of the outer circumferential surface  311   a  of the annular projection  311 . 
         [0042]    In order to form the roller  300  of  FIG. 1  by using the die according to the first embodiment including the configuration as described above, firstly, as illustrated in  FIGS. 2 and 3 , the axial core member  310  is inserted between the first split mold  1  and the second split mold  2  separated from each other, and is positioned such that one axial end  312  thereof is located between the tear-off portion molding surfaces  13 ,  23  and the annular projection  311  is located between the support portions  11 ,  21 . Then, the axial core member  310  is placed on the support portion  21  of the second split mold  2  to be mold lamped. The mold clamping, as illustrated in  FIGS. 4 and 5 , brings the inner circumferential surfaces  11   a ,  21   a  of the support portions  11 ,  21  into close contact with the outer circumferential surface  311   a  of the annular projection  311  at an appropriate surface pressure, such that the axial core member  310  is supported and fixed between the first split mold  1  and the second split mold  2  and the cylindrical cavity A is defined between the outer circumferential surface of the axial core member  310  and the roller body molding surfaces  12 ,  22 , and a tear-off portion molding space B is defined between one axial end  312  in the axial direction of the axial core member  310  and the tear-off portion molding surfaces  13 ,  23 . 
         [0043]    At this time, end surfaces of the support portions  11 ,  21  on the cavity A side are located over the outer periphery of the annular grooves  313 ,  314 , and end surfaces of the support portions  11 ,  21  on the tear-off portion molding space B side are located over the outer periphery of the annular grooves  313 ,  314 . 
         [0044]    The annular projection  311  of the axial core member  310  is subject to compressive deformation due to mold clamping between the support portion  11  of the first split mold  1  and the support portion  21  of the second split mold  2 . However, since recesses  14 ,  24  are formed at both end portions of the support portions  11 ,  21 , the recesses extending along the parting surfaces  1   a ,  2   a , and being not in contact with the outer circumferential surface  311   a  of the annular projection  311  of the axial core member  310  at the time of mold clamping, the outer circumferential surface  311   a  of the annular projection  311  is prevented from being bitten between the end portions of the support portions  11 ,  21  (between the parting surfaces  1   a ,  2   a ). The first split mold  1  and the second split mold  2  are therefore not obstructed from being closed, and the parting surfaces  1   a ,  2   a  are brought into close contact with each other. 
         [0045]    Further, since the axial width of the annular projection  311  becomes narrower toward the outer diameter side, deformation due to mold clamping mainly occurs on the annular projection  311  side, and damage to the support portions  11 ,  21  (the first split mold  1  and the second split mold  2 ) is suppressed. In addition, since in width w 1  in the axial direction of the support portions  11 ,  21  and in width w 2  in the axial direction of the annular grooves  313 ,  314  are larger than in width w 3  in the axial direction of the outer circumferential surface  311   a  of the annular projection  311 , slight misalignment is allowable in placing the axial core member  310  between the first split mold  1  and the second split mold  2 . 
         [0046]    Next, for example, an uncrosslinked liquid rubber composition is injected into the die through an injection port (not illustrated) opened in the tear-off portion molding space B. The liquid rubber composition passes from the tear-off portion molding space B through the semicircular shaped gates C defined between the recesses  14 ,  24  formed at both end portions of the support portions  11 ,  21  and the outer circumferential surface  311   a  of the annular projection  311 , and fills inside the cavity A to be shaped. Then, the liquid rubber composition in the cavity A is crosslinked and cured, so that the roller body  320  integrated with the axial core member  310  is molded as illustrated in  FIGS. 6 and 7 . The liquid rubber composition in the gates C is crosslinked and cured, so that gate burrs  321  continuous with the roller body  320  are molded as illustrated in  FIG. 7 . The liquid rubber composition in the tear-off portion molding space B is also crosslinked and cured, so that a tear-off portion  322  continuous with the gate burrs  321  is molded as illustrated in  FIGS. 6 and 7 . In addition, the liquid rubber composition is crosslinked and cured between the annular grooves  313 ,  314  and the support portions  11 ,  21 , so that annular rims  323 ,  324  illustrated in  FIG. 6  are molded. 
         [0047]    At this time, as illustrated in  FIGS. 4 and 5  described above, since the outer circumferential surface  311   a  of the annular projection  311  and the inner circumferential surfaces  11   a ,  21   a  of the support portions  11 ,  21  are in close contact with each other at an appropriate surface pressure by mold clamping, the liquid rubber composition is prevented from permeating therebetween and from forming a thin burr. Since the parting surfaces  1   a  and  2   a  are also in close contact with each other, the liquid rubber composition is prevented from permeating therebetween and from forming a thin burr. 
         [0048]    Then, after opening the die by separating the first split mold  1  and the second split mold  2  from each other and taking out the molded article illustrated in  FIGS. 6 and 7 , the tear-off portion  322  is torn off by hand or the like, as illustrated in  FIG. 8 . The annular rim  324  and the gate burrs  321  which are continuous with the tear-off portion  322  are also torn off with the tear-off portion  322 , enabling deburring to be performed easily, and the roller  300  as a product is obtained. 
         [0049]    Although the annular rim  323  which is continuous with the roller body  320  remains even after the deburring, the annular rim  323  is formed relatively thick with the annular groove  313  of the axial core member  310 , and is not a thin burr. Therefore, when the roller  300  is used as an image forming roller, a pressurizing roller, or the like in a copying machine or the like, the annular rim  323  will not fall off from the axial core member  310  and will not be a foreign object. Thus, the annular rim  323  may be made less liable to fall off by making the annular groove  313  deeper to thereby make the annular rim  323  thicker. 
         [0050]    Next,  FIGS. 9 to 15  illustrate a second embodiment of a die for molding a roller according to the present invention. 
         [0051]    The second embodiment is different from the above-described first embodiment in that an axial core member  310  has a simple cylindrical shape and support portions  11 ,  21  of a first split mold  1  and a second split mold  2  has a shape in which in width w 1  in the axial direction decreases toward the inner diameter side in the vicinity of the inner diameter portion of the molds. Recesses  14 ,  24  extending axially through the support portions  11 ,  21  along parting surfaces  1   a ,  2   a  at both end portions of the respective support portions  11 ,  21  are not in contact with outer circumferential surface  310   a  of the axial core member  310  at the time of mold clamping, and defines semicircular gates C as illustrated in  FIG. 12  with the outer circumferential surface  310   a  of the axial core member  310 . The other parts can basically be configured similarly to the first embodiment. 
         [0052]    Molding by using the die according to the second embodiment including the configuration as described above is basically similar to the case according to the first embodiment. Specifically, first, as illustrated in  FIGS. 9 and 10 , the axial core member  310  is inserted between the first split mold  1  and the second split mold  2  separated from each other, and is positioned such that one axial end  312  of the axial core member is located between the tear-off portion molding surfaces  13 ,  23 . Then, the axial core member  310  is placed on the support portion  21  of the second split mold  2  to be mold clamped. The mold clamping, as illustrated in  FIGS. 11 and 12 , brings the inner circumferential surfaces  11   a ,  21   a  of the support portions  11 ,  21  into close contact with the outer circumferential surface  310   a  of the axial core member  310  at an appropriate surface pressure, such that the axial core member  310  is supported and fixed between the first split mold  1  and the second split mold  2  and the cylindrical cavity A is defined between the outer circumferential surface  310   a  of the axial core member  310  and the roller body molding surfaces  12 ,  22 , and a tear-off portion molding space B is defined between one axial end  312  of the axial core member  310  and the tear-off portion molding surfaces  13 ,  23 . 
         [0053]    At this time, a portion of the axial core member  310 , which is fixed between the support portion  11  of the first split mold  1  and the support portion  21  of the second split mold  2 , is subject to compressive force due to mold clamping. However, since recesses  14 ,  24  are formed at both end portions of the support portions  11 ,  21 , the recesses extending along the parting surfaces  1   a ,  2   a , and being not in Contact with the Outer Circumferential Surface  310   a  of the axial core member  310  at the time of mold clamping, the outer circumferential surface  310   a  of the axial core member  310  is prevented from being bitten between the end portions of the support portions  11 ,  21  (between the parting surfaces  1   a ,  2   a ). The first split mold  1  and the second split mold  2  are therefore not obstructed from being closed, and the parting surfaces  1   a ,  2   a  are brought into close contact with each other. 
         [0054]    In addition, the support portions  11 ,  21  of the first split mold  1  and the second split mold  2  are formed such that the vicinity of the inner diameter portion thereof has a shape in which in width w 1  in the axial direction decreases toward the inner diameter side, and therefore the support portions  11 ,  21  is easily compressed and deformed by the mold clamping force, to thereby be brought into a preferable state of favorable close contact with the outer circumferential surface  310   a  of the axial core member  310 . 
         [0055]    Next, for example, an uncrosslinked liquid rubber composition is injected into the die through an injection port (not illustrated) opened in the tear-off portion molding space B. The liquid rubber composition passes from the tear-off portion molding space B through the semicircular shaped gates C defined between the recesses  14 ,  24  formed at both end portions of the support portions  11 ,  21  and the outer circumferential surface  310   a  of the axial core member  310 , and fills inside the cavity A to be shaped. Then, the liquid rubber composition in the cavity A is crosslinked and cured, so that the roller body  320  integrated with the axial core member  310  is molded as illustrated in  FIGS. 13 and 14 . The liquid rubber composition in the gates C is crosslinked and cured, so that gate burrs  321  continuous with the roller body  320  is molded as illustrated in  FIG. 14 . The liquid rubber composition in the tear-off portion molding space B is also crosslinked and cured, so that a tear-off portion  322  continuous with the gate burrs  321  is molded as illustrated in  FIGS. 13 and 14 . 
         [0056]    At this time, as illustrated in  FIGS. 11 and 12  described above, since the outer circumferential surface  310   a  of the axial core member  310  and the inner circumferential surfaces  11   a ,  21   a  of the support portions  11 ,  21  are in close contact with each other at an appropriate surface pressure by mold clamping, the liquid rubber composition is prevented from permeating therebetween and from forming a thin burr. Since the parting surfaces  1   a ,  2   a  are also in close contact with each other, the liquid rubber composition is prevented from permeating therebetween and from forming a thin burr. 
         [0057]    Then, after opening the die by separating the first split mold  1  and the second split mold  2  from each other and taking out the molded article illustrated in  FIGS. 13 and 14 , the tear-off portion  322  is torn off by hand or the like, as illustrated in  FIG. 15 . The gate burrs  321  which is continuous with the tear-off portion  322  are also torn off with the tear-off portion  322 , enabling deburring to be performed easily.