JPH09300394A - Production of feed roller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inexpensively estabilish the mass production technique of a feed roller by applying rigidity to an integrated three-layered structure of a center shaft, an elastic inner layer and an elastic outer layer in a rotary direction and applying elasticity thereto in a diameter direction. SOLUTION: A process producing a hollow member 14 made of fluoroplastic having an outer peripheral surface having a circular cross section and opened at both ends thereof, a process inserting the center shafts 12 and the hollow member 14 into an injection mold so that the center shafts 12 hold the center axial line of the hollow member 14 in common, a process forming a closed cavity 26 by the molding surface of an injection mold, the inner surface of the hollow member 14 and the outer peripheral surfaces of the center shafts 12 and a process fusing the hollow member 14 and an elastomer by the fusion heat of the elastomer are provided. Rigidity is applied to the integral three- layered structure of the center shafts 12, an elastic inner layer and an elastic outer layer in a rotary direction and elasticity is applied thereto in a diameter direction to inexpensively mass-produce a feed roll.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a conveying roller. More specifically, the present invention relates to a method of manufacturing a carrying roller for manufacturing a carrying roller in which the materials of the central shaft and the two inner and outer layers of the rotating body are different.

[0002]

2. Description of the Related Art Conveying rollers are used in various fields. The surface of the transport roller may be required to have a uniform coefficient of friction with the transported object spatially and temporally. In this case, as known from JP-A-5-4399, a thermoplastic elastomer is used as the material of the roller. Further, in a roller which is required to have low radial rigidity and high circumferential rigidity, Japanese Patent Application Laid-Open No. 5-2:
In this case also thermoplastic elastomers are used, as is known from 17158. Furthermore, there is also known a roller in which an elastic body is used as a core material and the surface of the core material is coated with a material that is not easily worn. Different materials are often used for the central axis and the rotating body having the central axis as the center.

A dissimilar material insert injection molding means can be considered as a manufacturing method for mass-producing a two-layer structure rotating body having a central axis as a center, that is, a three-layer structure roller at a low cost. In this case, for example, it is disliked that a parting line is formed on the outer peripheral surface of the conveying roller of the copying machine. When molding is performed so that the parting line does not appear, a draft appears and it cannot be formed on the cylindrical surface.

Further, the central axis and the outer peripheral surface are required to be integrated. As a means for firmly joining the inner and outer two layers during injection molding of different materials, a heat developed by the applicant company in which two kinds of materials enter into protrusions on the other side to form a fusion layer in a sea-island shape in the joining region. Although fusion technology is known, combinations of materials that cause such heat fusion are limited, and for example, it is difficult to form a sea-island fusion layer between a fluororesin and various elastomers. .

It is necessary to mass-produce the conveying roller having a three-layer structure at low cost, to secure the rigidity of the entire three layers, to establish a manufacturing method of the conveying roller which has elasticity in the radial direction and has a smooth outer peripheral surface.

[0006]

The present invention has been made based on such a technical background, and achieves the following objects.

An object of the present invention is to provide a method for manufacturing a conveying roller having a smooth outer peripheral surface, which is rigid in the rotational direction and elastic in the radial direction, and which is different in material between two or three layers and can be mass-produced at low cost. To do.

Another object of the present invention is to form a smooth outer peripheral surface which is made of a material that is rigid in the rotational direction and elastic in the radial direction and has poor fusion bonding between two or three layers and can be mass-produced at low cost. An object of the present invention is to provide a method for manufacturing a transport roller.

Still another object of the present invention is to provide a low cost since it is rigid in the rotational direction, elastic in the radial direction, the outer layer is made of fluororesin, the inner layer is made of an elastic material, and the central axis is made of engineering plastic or metal. Another object of the present invention is to provide a method of manufacturing a transport roller having a smooth outer peripheral surface which can be mass-produced.

It is still another object of the present invention that the outer layer is made of fluororesin, the inner layer is made of elastomer, and the central axis is made of engineering plastic or metal, which is rigid in the rotational direction, elastic in the radial direction, and inexpensive. An object of the present invention is to provide a method of manufacturing a transport roller that can be mass-produced and has a smooth outer peripheral surface.

Still another object of the present invention is to provide a method for manufacturing a carrying roller in which the outer peripheral surface of the carrying roller for the above purpose is substantially a cylindrical surface.

Still another object of the present invention is to provide a method of manufacturing a carrying roller in which two or three layers of the carrying roller for the above purpose are integrated without fusion.

[0013]

The present invention employs the following means in order to solve the above problems.

In the method for manufacturing a conveying roller according to the first aspect of the present invention, a rotating body having an outer peripheral surface having a circular cross section and a central axis that axially penetrates the rotating body while sharing a central axis line of the rotating body. And both ends of the central shaft project in the axial direction from the rotating body, the rotating body is composed of at least two layers of an outer layer and an inner layer, and a material of the outer layer and a material of the inner layer are different, In the method of manufacturing a conveying roller in which the material of the rotating body and the material of the central shaft are different from each other, a step of manufacturing a hollow body having an outer peripheral surface having a circular cross section and open at both ends, A step of inserting the central shaft and the hollow body into an injection molding die so that the central axis shares the central axis of the hollow body, the injection molding die is closed and the molding surface of the injection molding die and the hollow body Closed with inner surface and outer surface of the central axis A step of forming a cavity, a step of injecting and injecting a melted elastic material into the cavity, a step of joining the hollow body and the elastic material by the heat of fusion of the elastic material and cooling the elastic material, and the rotating body And a step of forming.

A method of manufacturing a carrying roller according to a second aspect of the present invention is the method of manufacturing the carrying roller according to the first aspect of the invention, characterized in that the outer peripheral surface of the rotating body is substantially a cylindrical surface.

A third aspect of the present invention provides a method of manufacturing a carrying roller according to the first or second aspect of the present invention, wherein the material of the central shaft is a metal or a material selected from various engineering plastics. The elastic material is
It is characterized by being a material selected from a thermoplastic elastomer or various rubber materials.

According to a fourth aspect of the present invention, there is provided a method of manufacturing a carrying roller, wherein a rotating body having an outer peripheral surface having a circular cross section and a central axis of the rotating body which share a central axis of the rotating body and axially penetrate the rotating body. And both ends of the central shaft project in the axial direction from the rotating body, the rotating body is composed of at least two layers of an outer layer and an inner layer, and a material of the outer layer and a material of the inner layer are different, In the method of manufacturing a conveying roller in which the material of the rotating body and the material of the central shaft are different from each other, a step of manufacturing a hollow body having an outer peripheral surface having a circular cross section and open at both ends, A step of inserting the central shaft and the hollow body into an injection molding die so that the central axis shares the central axis of the hollow body, the injection molding die is closed and the molding surface of the injection molding die and the hollow body Closed with inner surface and outer surface of the central axis A step of forming a cavity, a step of injecting and injecting a melted elastic material into the cavity, a step of joining the hollow body and the elastic material by the heat of fusion of the elastic material and cooling the elastic material, and the rotating body And the elastic material is a material selected from a thermoplastic elastomer or various rubber materials, and the hollow The material of the body is a fluororesin.

A fifth aspect of the present invention provides a method of manufacturing a transport roller according to the fourth aspect of the present invention, which is characterized in that the inner peripheral surface of the hollow body is not a cylindrical surface.

A sixth aspect of the present invention is a method of manufacturing a transport roller according to the fourth aspect of the present invention, which is characterized in that the joint surface between the central shaft and the rotating body is not a cylindrical surface.

A method of manufacturing a carrying roller according to a seventh aspect of the present invention is the method of manufacturing a carrying roller according to the fourth aspect of the present invention, characterized in that the elastic material contains a conductive substance.

An eighth aspect of the present invention provides a method of manufacturing a carrying roller according to the first aspect of the present invention, wherein the hollow body manufacturing step is extrusion molding.

In the method of manufacturing the carrying roller of the present invention, the inner peripheral surface of the outer layer and the outer peripheral surface of the inner layer are substantially in close contact with each other. That is, the inner layer is completely packed inside the outer layer, and both layers are faithful or solid. In this manner, the inner or outer contact layers or contact layers that are in close contact with each other as a solid form a joint surface or a joint layer even if they are not fusion layers. Even if the joining force of the joining layer, for example, the Wanderwers force, is small, the entire surface is the joining surface, so that the inner and outer layers are formed as a substantially complete unit in the rotational direction. In the direction of rotation, the coupling is more complete than by taper surface coupling.

That is, when the inner layer receiving the rotational force receives a rotation inhibiting force from the outer layer and is distorted even slightly, the relative rotation of the inner layer and the outer layer is completely prevented up to the fracture limit. Such characteristics of the relationship between the inner and outer layers also apply to the relationship between the central axis and the inner layer. The transport roller manufactured in this manner has high rigidity in the rotation direction.

Even when the outer layer is made of fluororesin and the inner layer is made of elastomer, the rigidity in the rotation direction is high. The inner layer has elasticity in the radial direction due to the elasticity in the radial direction. If the central axis is an engineering plastic, the fusion bonding surfaces of the central axis and the inner layer have a small radius but are completely integrated in the rotational direction by heat fusion, which is the invention of the present inventor.

The outer peripheral surface of the outer layer having no parting line is smooth. The outer layer can be mass-produced at low cost by extrusion molding. The inner layer can be mass-produced by ordinary injection molding. Dissimilar material injection molding, in which the outer layer and the central axis are inserted into the mold and the inner layer is molded by injection molding, is a low-cost mass production technique. As described above, the present invention can be configured only by inexpensive molding technology. When the central axis is made of metal, the mass production cost of the metal is added, but it does not cost more. If the material of the inner layer contains a conductive material, the inner layer can be easily provided with conductivity.

The rotationally integrated structure of the inner and outer layers is further strengthened by making the inner peripheral surface of the outer layer a non-cylindrical surface, for example, a conical surface or an elliptical surface. In this case, it is not necessary to join the inner and outer layers as long as the inner and outer layers are faithful. This relationship is the same as the relationship between the central axis and the inner layer.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of a method for manufacturing a carrying roller according to the present invention will be described. FIG. 1 shows a carrying roller 11 manufactured according to a first embodiment of the method for manufacturing a carrying roller of the present invention. The transport roller 11 is composed of three layers, as shown in FIG. The central layer is the central axis 12 as a rotation axis. As a layer outside the central axis 12,
The inner layer 13 is formed. An outer layer 14 is formed as an outer layer of the inner layer 13. The rotating body 15 is formed by the inner layer and the outer layer.

The outer layer 14 itself forms a cylindrical body whose both ends are open, that is, a hollow body whose both ends are open. Inner layer 13
It itself also forms a hollow cylinder. Inner and outer layers 13, 14
The transport roller 11 composed of the center shaft 12 and the center shaft 12 is solid, that is, solid. The inner and outer layers 13, 14 and the central axis 12 share the central axis.

The outer peripheral surface of the outer layer 14 is substantially a cylindrical surface. On a cross section perpendicular to the axis at any axial position, the cylindrical surface is a circle with the same diameter. That is, no gradient is provided on the cylindrical surface. A substantially cylindrical surface means that a draft required for molding, for example, is not provided. Outer layer 14
Is manufactured in large quantities at low cost by cutting a pipe manufactured by extrusion molding to a certain size. According to extrusion molding, the outer peripheral surface of the outer layer 14 is formed into a smooth surface, and there is no parting line formed when injection molding is performed using a split mold.

The central shaft 12 penetrates the rotating body 15. Both ends of the central shaft 12 project in the axial direction from the end surface of the rotating body 15 perpendicular to the axis. The material of the outer layer 14 and the material of the inner layer 13 are different. The material of the rotating body 15 and the material of the central shaft are different. The material of the outer layer 14 is a fluororesin and has an electrostatic property. The inner layer 13 is formed of a material having elasticity.

The elastic material of the inner layer 13 is various rubber materials and various elastomers. The material of the central shaft 12 is a hard material such as metal and is harder than the inner layer. As such hard materials, engineering materials with various physicochemical properties such as ABS resin, PP, polycarbonate, etc.
At least one type can be selected from plastic.

As the elastomer, various kinds of elastomers such as polyether elastomer, polyether ester elastomer and nylon elastomer are known. It has been confirmed by the present inventors that the polyether elastomer and the ABS resin are fused in a sea-island shape under a certain pressure of the molten elastomer.

Other combinations of materials that fuse in this way are known. For example, polycarbonate and elastomer also fuse well. However, at the current research stage, the fusion property between the fluororesin and the elastomer is not so good. It is only to the extent that joining due to the Wanderwers force is recognized,
It has no fusogenicity but has adhesiveness.

FIG. 3 shows a die unit used in the method of manufacturing the above-mentioned transport roller 11. The upper and lower dies or the left and right dies that are relatively movable are used. Such a mold is composed of a fixed side mold element 21 and a movable side mold element 22. The fixed-side mold element 21 is formed with a fixed-side large-diameter semi-cylindrical surface 23 facing the movable-side mold element 22.

The movable side mold element 22 is formed with a movable side large diameter semi-cylindrical surface 24 facing the fixed side mold element 21. When the fixed-side mold element 21 and the movable-side mold element 22 are closed, the fixed-side large-diameter semi-cylindrical surface 23 and the movable-side large-diameter semi-cylindrical surface 2
4 forms one large diameter cylindrical surface 27. The large-diameter cylindrical surface 27 has almost the same shape as the outer peripheral surface of the outer layer 14 described above.

The fixed-side mold element 21 is formed with a fixed-side small diameter semi-cylindrical surface 25 facing the movable-side mold element 22. The movable side mold element 22 is formed with a movable side small diameter semi-cylindrical surface 26 facing the fixed side mold element 21. Fixed-side mold element 21
When the movable mold element 22 and the movable mold element 22 are closed, the fixed small diameter semi-cylindrical surface 25 and the movable small diameter semi-cylindrical surface 26 form one small diameter cylindrical surface 28. This small-diameter cylindrical surface has almost the same shape as the outer peripheral surface of the central shaft 124 described above.

A small-diameter cylindrical surface 28 formed by the fixed-side small-diameter semi-cylindrical surface 25 and a movable-side small-diameter semi-cylindrical surface 26, a large-diameter cylinder formed by the fixed-side large-diameter semi-cylindrical surface 23 and a movable-side large-diameter semi-cylindrical surface 24. The faces 27 share the same axis. Small-diameter cylindrical surface 2 formed by fixed-side small-diameter semi-cylindrical surface 25 and movable-side small-diameter semi-cylindrical surface 26
Reference numeral 8 denotes a large diameter semi-cylindrical surface 23 on the fixed side and a large diameter semi-cylindrical surface 2 on the movable side.
It is provided on both sides of the large-diameter cylindrical surface 27 formed by 4.

The small-diameter cylindrical surface formed by the fixed-side small-diameter semi-cylindrical surface 25 and the movable-side small-diameter semi-cylindrical surface 26 on one side is a large surface formed by the fixed-side large-diameter semi-cylindrical surface 23 and the movable-side large-diameter semi-cylindrical surface 24. It is connected to one end of the radial cylindrical surface by one axis-perpendicular surface 29. The small-diameter cylindrical surface formed by the fixed-side small-diameter semi-cylindrical surface 25 and the movable-side small-diameter semi-cylindrical surface 26 on the other side is a large-diameter cylindrical surface formed by the fixed-side large-diameter semi-cylindrical surface 23 and the movable-side large-diameter semi-cylindrical surface 24. Is connected to the other end by the axis-perpendicular surface 31.

After the mold is opened, the outer layer 14 having the central shaft 12 passed therethrough is inscribed in the movable large-diameter semi-cylindrical surface 24 and is inserted into the movable mold element 22. This outer layer 14 has been produced in a preceding extrusion process. Also, the central axis 12
Is manufactured in the preceding injection molding process. Then, the central shaft 12 is inscribed in the small-diameter cylindrical surface 28 and inserted into the movable mold element 22. Central axis 1 by this insert
The relative positioning of 2 and the outer layer 14 is performed.

FIG. 4 also shows the mold closed state. When the mold is closed, the outer layer 14 is inscribed in the large diameter cylindrical surface 27, and the central shaft 12 is inscribed in the small diameter cylindrical surface 28. By closing the mold, as shown in FIG. 4, by the inner peripheral surface 32 of the outer layer 14, the outer peripheral surface 34 of the central shaft 12, and the axially perpendicular surfaces 29, 31 of both molds 21 and 22 (molding surface of the injection molding mold). A closed cylindrical cavity 36 is formed. The fixed side mold element 21 is provided with spools and gates 37 at two positions.

The molten material is injected and injected from the gate 37.
A thermoplastic elastomer is used as the molten material. The molten material fills the cavity 36. The molten material melts the surface layer portion of the ABS resin, which is the material of the central shaft 12.
Both molten materials plunge into each other in a protrusion shape due to thermal motion, and enter a sea-island shape when viewed in cross section.

Such a sea-island rush occurs under the conditions of an appropriate temperature and pressure of the molten material. Such a heat seal layer has a width of about 10 microns. From the main protrusion, countless small protrusions with a width of about 1 micron further emerge, and nested sea islands are formed. The pressure determines the density of the elastomer, which is the molten material. The molten material applies thermal vibration energy to the inner surface side of the fluororesin forming the outer layer 14 to bond it.

At present, the above-described fusion bonding does not occur in the bonding layer. If the central axis is a metal body, the elastomer and the metal body are joined and not fused. The elastic material can be selected from various rubber materials instead of the thermoplastic elastomer.

FIG. 5 shows a modification of the outer layer 14.
The outer peripheral surface is a cylindrical surface, but the inner peripheral surface 41 is slightly elliptical on the cross section perpendicular to the axis. Such outer layer 14 can also be easily manufactured by extrusion molding. Instead of the elliptical shape, a gear shape can be used. In addition, by forming a shape other than a perfect circle such as a tapered surface, it is possible to impart high rigidity to both layers 13 and 14 in the rotational direction as a relationship with the inner layer 13. The manufacturing method of the transport roller 11 using such an outer layer 14 is exactly the same as the manufacturing method shown in FIGS.

FIG. 6 shows a modification of the central shaft 12. The cross-section perpendicular to the axis of the central region 12a of the central axis 12 has a slightly elliptical shape. Instead of the elliptical shape, a gear shape can be used. In addition, by forming a shape other than a perfect circle such as a tapered surface, it is possible to give the inner layer 13 and the central shaft 12 high rigidity in the rotational direction as a relationship with the inner layer 13.

The manufacturing method of the conveying roller 11 using the central shaft 12 is exactly the same as the manufacturing method shown in FIGS. By producing the outer layer 14 by extrusion molding, it is not necessary to form the outer peripheral surface of the outer layer 14 into a tapered surface, and it is not necessary to perform post-processing such as surface polishing.

FIG. 7 shows a modified example of the outer layer 14 in which the bonding auxiliary layer 42 is formed by subjecting the inner peripheral surface of the outer layer 14 to a primer process. It is possible to strengthen the joint structure between the outer layer 14 and the inner layer 13 by previously forming such a joining auxiliary layer 41 and performing insert molding of a different material by the same method as the manufacturing method shown in FIGS. . In addition, the fused structure can be strengthened. Outer layer 14 and bonding auxiliary layer 42
Can be extruded doubly and molded.

Since the radius of the joint surface between the outer layer and the inner layer is larger than the radius of the joint surface between the central axis and the inner layer, the joint force between the outer layer and the inner layer is smaller than the joint force between the central axis and the inner layer. However, the rigidity in the rotational direction of both joint surfaces can be made equal.

FIG. 8 shows a second embodiment of the carrying roller 11 of the present invention. The transport roller 11 has three layers.
The central layer is the central axis 12 as a rotation axis. Central axis 1
An inner layer 13 is formed as an outer layer of the second layer. An outer layer 14 is formed as an outer layer of the inner layer 13. The rotating body 15 is formed by the inner layer and the outer layer.

The outer layer 14 itself forms a cylindrical body with both ends open, that is, a hollow body with both ends open. Inner layer 13
It itself also forms a hollow cylinder. Inner and outer layers 13, 14
The transport roller 11 including the central shaft 12 and the central shaft 12 is not solid (solid). A space 51 is formed between the central shaft 12 and the outer layer 14 except for both ends. The inner and outer layers 13, 14 and the central axis 12 share the central axis.

The outer peripheral surface of the outer layer 14 is substantially a cylindrical surface. On a cross section perpendicular to the axis at any axial position, the cylindrical surface is a circle with the same diameter. That is, no gradient is provided on the cylindrical surface. The outer layer 14 is mass-produced at low cost by cutting a pipe manufactured by extrusion molding to a predetermined size.
The outer layer 14 has no parting line.

The central shaft 12 penetrates the rotating body 15. Both ends of the central shaft 12 project in the axial direction from the end surface of the rotating body 15 perpendicular to the axis. The material of the outer layer 14 and the material of the inner layer 13 are different. The material of the rotating body 15 and the material of the central shaft are different. The material of the outer layer 14 is a fluororesin and has an electrostatic property. The inner layer 13 is formed of a material having elasticity.

Both ends of the outer layer 14 (only one is shown in the drawing)
The inner surface of is formed into a small-diameter cylindrical surface 52 for fitting. A partition 53 is softly fitted into the small-diameter cylindrical surface 52 from the end. The partition wall 53 is formed of a partition wall large-diameter portion 54 softly inscribed in the small-diameter cylindrical surface 52 and a partition wall small-diameter portion 55 directed toward the center. The partition large diameter portion 54 and the partition small diameter portion 55 are integrally molded of resin. The resin material is the same material as the central axis.

The central axis 12 penetrates the partition wall 53, and the outer layer 14
Is supported by the central shaft 12 via a partition wall 53. The positioning accuracy between the central shaft 12 and the outer layer 14 is determined by the small diameter cylindrical surface 52.
And the concentricity accuracy of the central axis hole 56 of the partition wall 53. The concentricity of the small diameter cylindrical surface 52 can be obtained to the required degree by machining, such as turning. The concentricity of the central shaft hole 56 can be obtained to the required degree by the resin molding technique.

The outer layer 14, the partition wall 53 and the central shaft 12 are preassembled. The assembly thus assembled is inserted into the mold device shown in FIGS. Embodiment 2
For, the mold device used in the first embodiment can be used as it is. Molding conditions such as pressure are slightly different.

FIG. 8 shows the mold device of FIG. 4 in phantom. The inner peripheral surface 32 of the outer layer 14 (same as the small diameter cylindrical surface 52), the outer peripheral surface 34 of the central shaft 12, the axially perpendicular surfaces 29, 31 (molding surface of the injection molding mold) of both molds 21 and 22, and the partition wall large diameter portion. 54
A cylindrical closed cavity 36 by the outer end face 57 of the
Are formed. In the second embodiment, the cavity 36
Are formed at two locations on both sides.

When the elastomer is injected and injected from the gate 37 into the cavity 36, the partition wall 53 is pushed toward the center by the pressure in the cavity, but stops in contact with the step wall surface located at the right end of the small diameter cylindrical surface 52. Cavity 36
The molten molding material satisfying the above conditions penetrates into a slight gap between the small diameter cylindrical surface 52 and the outer peripheral surface of the partition wall 53 to fill the gap.

By adjusting the density of the molding material so that the specific gravity of the molding material and the specific gravity of the outer layer 14 are the same, the density distribution of the transport roller 11 can be made isotropic with respect to the central axis.
This isotropy allows the transport rollers to rotate at high speed. The penetration of the molten material increases the adhesion between the outer layer and the partition 53. The inner layer 13 is fused to the central shaft 12 and the partition wall 53 and adhered to the outer layer.

FIG. 9 shows an embodiment in which the carrying roller 11 of the second embodiment is further modified. The transport roller 11 of this embodiment is provided with a modified partition wall 53a which is a modification of the partition wall 53 of the second embodiment. That is, the modified partition wall 53a has a plurality of openings 61 arranged concentrically at equiangular positions.
(Three) are open.

The second partition 62 is inserted closer to the center than the modified partition 53a. The central axis of the second partition 62 penetrates concentrically, and the central axis 12 and the second partition 62 are already integrally joined. The central shaft 12 and the second partition wall 62 can be integrally manufactured by integral molding. The other points are the same as those of the second embodiment, and there is no difference.

Also in this embodiment, the mold apparatus shown in FIGS. 3 and 4 used in the first embodiment can be used. When the mold is closed, the cavity 36 is connected to another cavity 63. The other cavity 63 is a space surrounded by the inner peripheral surface of the outer layer 14, the exposed surface of the modified partition wall 53 a, the outer surface of the second partition wall 62, and the outer peripheral surface of the central shaft 12.

When the molten molding material is injected and injected from the gate 37, the molten material filling the cavity 36 is opened 61.
Through to fill other cavities 63 as well. The molten material permeates a small gap between the small diameter cylindrical surface 52 and the outer peripheral surface of the partition wall 53 to fill the gap. By adjusting the density of the molding material so that the specific gravity of the molding material and the specific gravity of the outer layer 14 are the same, the density distribution of the transport roller 11 can be made isotropic with respect to the central axis. This isotropy allows the transport rollers to rotate at high speed.

The penetration of the molten material increases the adhesion between the outer layer and the partition 53. Inner layer 13 is center axis 12 and partition wall 5
3 and fused to the outer layer. The molding material that fills the other cavity 63 is fused to the second partition wall 62, the modified partition wall 53 a, and the central shaft 12, and adheres to the outer layer 14. In this embodiment, the supporting relationship between the central shaft 12 and the outer layer 14 is strengthened as compared with that in the second embodiment, and the total weight of the transport roller 11 is reduced as compared with that in the first embodiment. By changing the position of the second partition 62, the weight and the support strengthening force can be changed.

Matters peculiar to each embodiment can be applied to other embodiments to be improved or modified. A conductive material may be contained in the molding material of the inner layer 13 and the central shaft 12, and a current or a voltage may be applied to the inner layer and the central shaft to charge the outer layer and reversely remove the charge.

[0065]

According to the method of manufacturing a carrying roller of the present invention, it is possible to reduce the mass production of a carrying roller having a three-layer structure in which elasticity is imparted in the radial direction and rigidity is imparted in the rotational direction.

[Brief description of drawings]

FIG. 1 is an oblique-axis projection view showing a carrying roller manufactured by a method for manufacturing a carrying roller according to the present invention.

FIG. 2 is a cross-sectional view of FIG.

FIG. 3 is a cross-sectional view showing a mold device used in an embodiment of a method for manufacturing a transport roller according to the present invention.

FIG. 4 is a sectional view in which a part of FIG. 3 is sectioned.

FIG. 5 is a cross-sectional view showing a modified example of the outer layer of the transport roller.

FIG. 6 is a cross-sectional view showing a modified example of the central axis of the transport roller.

FIG. 7 is a cross-sectional view showing a modified example of the transport roller.

FIG. 8 is a cross-sectional view showing a second embodiment of the method for manufacturing a transport roller of the present invention.

FIG. 9 is a cross-sectional view showing another embodiment of the method for manufacturing the carry roller of the present invention.

[Explanation of symbols]

 11 ... Conveying roller 12 ... Central axis 13 ... Inner layer 14 ... Outer layer (hollow body) 15 ... Rotating body 21 ... Fixed-side mold element (injection molding die) 22 ... Movable-side mold element (injection molding die) 23 ... Fixed-side large diameter Semi-cylindrical surface 24 ... Movable-side large-diameter semi-cylindrical surface 25 ... Fixed-side small-diameter semi-cylindrical surface 26 ... Movable-side small-diameter semi-cylindrical surface 29, 31 ... … External surface of the central axis 36… Cavity

Claims (8)

[Claims] 1. A rotating body having an outer peripheral surface having a circular cross section, and a central axis that axially penetrates the rotating body while sharing a central axis center line of the rotating body, and the central axis has both end portions. Projecting in the axial direction from the rotating body, the rotating body is composed of at least two layers of an outer layer and an inner layer, the material of the outer layer is different from the material of the inner layer, and the material of the rotating body and the center axis are different from each other. In a method of manufacturing a transport roller for manufacturing transport rollers of different materials, a step of manufacturing a hollow body having an outer peripheral surface having a circular cross section and open at both ends, wherein the central axis is the central axis of the hollow body. A step of inserting the central shaft and the hollow body into an injection molding die so as to be shared, and closing the injection molding die to form a molding surface of the injection molding die, an inner surface of the hollow body, and an outer peripheral surface of the central axis. Forming a closed cavity, said A step of injecting a molten elastic material into a cavity and injecting it, a step of joining the hollow body and the elastic material with the heat of fusion of the elastic material and cooling the elastic material to form the rotating body Roller manufacturing method. 2. The method of manufacturing a carrying roller according to claim 1, wherein the outer peripheral surface of the rotating body is a substantially cylindrical surface. 3. The method of manufacturing a transport roller according to claim 1, which is selected from claim 1 and claim 2, wherein the material of the central shaft is a metal or a material selected from various engineering plastics, The method for manufacturing a carrying roller, wherein the elastic material is a material selected from a thermoplastic elastomer or various rubber materials. 4. A rotating body having an outer peripheral surface having a circular cross section, and a central axis that axially penetrates the rotating body while sharing a central axis center line of the rotating body, and the central axis has both end portions. Projecting in the axial direction from the rotating body, the rotating body is composed of at least two layers of an outer layer and an inner layer, the material of the outer layer is different from the material of the inner layer, and the material of the rotating body and the center axis are different from each other. In a method of manufacturing a transport roller for manufacturing transport rollers of different materials, a step of manufacturing a hollow body having an outer peripheral surface having a circular cross section and open at both ends, wherein the central axis is the central axis of the hollow body. A step of inserting the central shaft and the hollow body into an injection molding die so as to be shared, and closing the injection molding die to form a molding surface of the injection molding die, an inner surface of the hollow body, and an outer peripheral surface of the central axis. Forming a closed cavity, said A step of injecting and injecting a melted elastic material into the cavity; a step of joining the hollow body and the elastic material with the heat of fusion of the elastic material and cooling the elastic material to form the rotating body, The material of the central shaft is a material selected from metal or various engineering plastics, the elastic material is a material selected from thermoplastic elastomer or various rubber materials, and the material of the hollow body is fluororesin. A method of manufacturing a carrying roller, comprising: 5. The method of manufacturing a carrying roller according to claim 4, wherein the inner peripheral surface of the hollow body is not a cylindrical surface. 6. The method of manufacturing a transport roller according to claim 4, wherein the joint surface between the central shaft and the rotating body is not a cylindrical surface. 7. The method of manufacturing a carrying roller according to claim 4, wherein the elastic material contains a conductive substance. 8. The method of manufacturing a carrying roller according to claim 1, wherein the step of manufacturing the hollow body is extrusion molding.