JPH08267472A - Manufacture of roll and roll mold - Google Patents

Abstract

PURPOSE: To provide a method for manufacturing a roll without flash and without decreasing the mold releasability, deforming a mandrel, and damaging the mold. CONSTITUTION: This method for manufacturing a roll comprises the steps of disposing a mandrel 2 having a different material from that of a mold 1 in the mold 1, casting a rubber in a space formed between the inner surface of the mold 1 and the outer surface of the mandrel 2, and then heating to vulcanize and to mold it. Elongation absorbing means which so has a movable member 3 and a spring material 4 in the mold 1 as to absorb the axial elongation of the mandrel 2 by the heat applied at the time of thermally vulcanizing in the case of thermally elongating it in an axial direction is disposed in the mold 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roll manufacturing method and a roll forming die.

[0002]

2. Description of the Related Art In an electrophotographic copying machine, as a means for fixing a toner image transferred on a paper, the paper is passed between a pair of rolls having a heat source such as a halogen lamp inside so as to remove the toner. There is a hot roll fixing method in which the paper is melted by heating and penetrated into the paper by the pressure between the rolls.
As a roll used in this method, one having a structure in which a highly releasable layer is formed on the outer peripheral portion of a core metal by coating with a fluororesin or the like is generally used, and a roll surface layer or an intermediate layer is used in a full-color copying machine or the like. A structure having an elastic layer made of silicone rubber or the like is used. As shown in FIG. 5, a method of molding a roll 10 (see FIG. 4) in which a rubber layer 12 made of silicon rubber or the like is provided on the outer peripheral portion of a core metal 11 as in the above-described roll, is divided into upper and lower two-part type as shown in FIG. Mold 1
3. The core metal 11 is set in the molding space 14 formed inside 3, and the rubber material is injected into the space 15 formed between the inner peripheral surface of the mold 13 and the outer peripheral surface of the core metal 11 (Fig. After that (see the arrow inside), a die molding method of heating under pressure and vulcanization molding is mainly used. In FIG. 5, 16 is (molding space 1
4 is formed when the core metal 11 is set in 4) The core metal 11
And 17 is a rubber inlet.

[0003]

In the fixing roll of the above heat roll fixing system, in order to secure a sufficient amount of heat transfer for melting the toner, the core bar 11 is made of aluminum or an aluminum-based alloy having a good thermal conductivity. It is common to use different materials. Further, as the material of the mold 13 used for rubber molding, iron or iron-based metal is generally used from the viewpoint of durability, workability and the like. On the other hand, when using such a mold, it is necessary to set the clearance 16 formed between the core metal 11 and the mold 13 to be small in order to reduce the leakage of the injection material such as rubber. That is, if the clearance 16 is large, the amount of leakage of the rubber material 18 becomes a loss or a burr 19 (see FIG. 6), which leads to a decrease in demolding property due to burr biting, and a deburring process is required. Also, it is disadvantageous in terms of processing cost.

However, when the coefficient of linear expansion of the core metal 11 greatly exceeds the coefficient of linear expansion of the mold 13, such as a combination of using aluminum for the core metal 11 and iron for the mold 13, (for example, aluminum wire). Expansion coefficient: 24.3 × 10
^-6 / ° C., linear expansion coefficient of iron: 11.1 × 10 ^-6 / ° C.), and there is a problem that the clearance 16 cannot be set small. That is, the vulcanization temperature (generally 12
Dimensional change occurs due to the difference in linear expansion between 0 ° C. and 200 ° C. (clearance 16 changes and there is a difference in clearance 16 between vulcanization and room temperature), and the clearance 16 cannot be properly held. . This is particularly remarkable in the axial direction of the cored bar 11. For example, when the clearance 16 is increased in consideration of the axial dimensional change of the cored bar 11, problems such as burrs occur as described above. On the contrary, when the clearance 16 is reduced in order to prevent burrs from being generated, the core metal 1 due to dimensional change due to linear expansion.
A large force is applied between the mold 1 and the mold 13 to cause problems such as deterioration of demolding property, deformation of the cored bar 11 and damage to the mold 13.

The present invention has been made in view of such circumstances, and a roll which does not cause burrs or the like, deterioration of demolding property, deformation of a cored bar, damage to a molding die, etc. And a roll forming die.

[0006]

In order to achieve the above object, the present invention provides a molding die in which a cored bar made of a material different from that of the molding die is disposed, and the inner surface of the molding die and the outer surface of the cored bar are formed. A method of manufacturing a roll that is heated and vulcanized and molded after injecting rubber into a space formed therebetween, so that the core metal absorbs the elongation when thermally expanding in the axial direction by the heat applied during the heat vulcanization, The first gist is the manufacturing method of the roll in which the expansion absorbing means is arranged in the molding die to absorb the thermal expansion of the core metal, and the core metal is arranged in the molding space to A roll molding die for heat-vulcanizing and molding after injecting rubber into a space formed between the inner surface and the outer surface of the core metal,
A roll forming die in which a movable member for gripping an end portion of the cored bar in the axial direction is arranged on one end side of the molding space and a spring member for urging the movable member against the cored bar is arranged. Is the second gist.

[0007]

That is, according to the roll manufacturing method of the present invention, the core metal having a different material from that of the mold is arranged in the molding die, and the expansion absorbing means is also arranged, and the inner surface of the molding die and the outer surface of the core metal are arranged. When the rubber is injected into the space formed between the cores and then the core is thermally vulcanized and molded, the elongation absorption means absorbs the axial thermal expansion of the cored bar. Therefore, even if the molding die and the cored bar made of a different material from each other thermally expand due to the heating during the heat vulcanization, the difference in thermal expansion between the two can be absorbed by the expansion absorbing means. Therefore, even when the clearance at room temperature formed between the molding die and the core metal is set small (appropriately), the clearance during the heating vulcanization hardly changes, and the small clearance Can be (properly) maintained. As a result, unlike the conventional example, a large force is not applied between the core metal 11 and the molding die 13 at the time of heat vulcanization, and the demoldability is reduced, the core metal 11 is deformed, the molding die 13 is damaged, and the like. The problem no longer occurs. In addition, since the clearance can be set small as described above, the occurrence of burrs can be significantly reduced, the demolding property is improved, and the deburring process is unnecessary, resulting in material cost and processing cost. In terms of On the other hand, according to the roll forming die of the present invention, the above manufacturing method can be realized easily and efficiently. Further, in the present invention, the extension absorbing means is composed of a movable member that holds the end of the cored bar and is movable in the axial direction of the cored bar, and a spring member that presses and urges the movable member against the cored bar. In this case, the extension absorbing means is composed of two parts, and the structure is simple. When the mold is an iron mold and the core is an aluminum cylinder, a core made of an aluminum cylinder excellent in durability, workability, etc. of the mold and having good thermal conductivity. The gold can ensure a sufficient amount of heat transfer for melting the toner. Moreover,
In this invention, the above-mentioned excellent effects can be obtained even though the materials having different linear expansion coefficients are used. Further, the core metal is a shaft body having a rotary shaft portion protruding from both end surfaces thereof, and a concave portion engaging with the rotary shaft portion is formed on the other end surface of the movable member and the other end surface of the molding space. in case of,
There is an advantage that the core metal can be accurately positioned and fixed in the molding space by utilizing the rotary shaft portion and the concave portion.

Next, the present invention will be described in detail.

The roll manufacturing method of the present invention uses a molding die, a cored bar made of a material different from that of the molding die, and an elongation absorbing means arranged in the molding die.

The material of the forming die is not particularly limited, and examples thereof include metal materials generally used for dies such as iron, iron-based alloys, stainless steel, alloy tool steel and high speed tool steel. In particular, when iron is used, it is advantageous in terms of durability and workability. The overall shape of the molding die is not particularly limited, and is appropriately selected according to the shape of the core metal.

As the material of the core metal, it is sufficient to select materials having different materials in combination with the molding die, and examples thereof include metal materials such as iron, aluminum, iron-based alloy, and stainless steel. Further, a resin having heat resistance such as an epoxy resin or a phenol resin can be used.
In particular, when aluminum is used, it has an advantage that sufficient heat transfer for melting the toner can be secured because aluminum has good thermal conductivity. Also,
As the core metal, a solid metal core or a hollow metal core can be used. In particular, in the case of using a hollow shape, the shape is appropriately selected from various hollow shapes such as a small diameter at both ends, a large diameter at the hollow portion, and the same diameter at each portion, in accordance with the outer shape of the core metal. Further, such a cored bar usually has a rotary shaft portion protruding from both end surfaces thereof.

The extension absorbing means comprises a movable member and a spring material.

The material of the movable member is not particularly limited, and examples thereof include metal materials such as iron, iron-based alloys, stainless steel, alloy tool steel and high speed tool steel, phenol resin, fluororesin and the like. In particular, when high-speed tool steel is used, it is advantageous in terms of wear resistance and durability of the moving part. The structure of the movable member is also not particularly limited, and the clearance is 0.1 mm or less (desirably about 0.01 to 0.05 mm) in order to maintain the accuracy of the molded product and prevent the injected rubber material from leaking. It is preferable to set to. Such a movable member may be provided along a direction in which the core metal used has the maximum expansion, which is the maximum length direction of the core metal, that is, the axial direction of the core metal.

The type of the spring material is not particularly limited, and it is necessary to select a material having a sufficient compression (elongation) dimension with respect to the dimensional change of the core metal. It is important to set the spring constant so that the elastic force due to the compression (expansion) dimension due to the dimensional change of the core metal is equal to or less than the plastic deformation strength of the core metal. Further, since the clearance between the core metal and the molding die can be reduced by pressing the movable member against the core metal, it is preferable that the spring material is in a contracted state when the core metal is inserted. The pressing force is not particularly specified except that it is set higher than the injection pressure of the rubber material. However, when the material pressure in the mold becomes higher than the injection pressure due to volume expansion or the like after the injection, it is preferable to set the pressing force above the material pressure.

The rubber to be injected is not particularly limited, and natural rubber (NR) and various synthetic rubbers (NB) are used.
R, SBR, BR, IR, CR, IIR, EDPM, silicone rubber) are used.

A sealing material (for example, an O-ring) may be inserted in the moving region of the movable member to enhance the effect of preventing the injected rubber material from leaking. It is also conceivable to dispose such an O-ring in the axial clearance of the cored bar (for example, to attach it between the one end face of the cored bar and the end face of the movable member facing this one end face). In this case, the O-ring also elastically contracts due to thermal expansion during heat vulcanization, but this elastic contraction amount is very small, and such elastic contraction of the O-ring is included in the absorption of thermal expansion in the present invention. Absent. Further, the sealing material may be used in each part of the molding die other than the moving area.

Next, examples of the present invention will be described.

[0018]

FIG. 1 shows an embodiment of the molding die of the present invention. In the figure, 1 is an upper and lower split type iron (S55C
2), which is a rotary shaft portion 2a, 2 having small diameters at both ends.
b shaped pipe (outer diameter 50m of large diameter part 2c)
m, length 400 mm) made of aluminum (A5056
Made) core metal. Further, 3 is a disk-shaped movable member made of iron (made of S55C) having a concave portion 3a formed on one side for holding the right rotation shaft portion 2a of the core metal 2, and 4 is made of hard steel wire (S
WB) spring material. A molding space 5 is formed inside the mold 1, and one side surface (the left side surface in the drawing) of the molding space 5 holds the left rotating shaft portion 2b of the core metal 2. A concave portion 1a for forming is formed.
The movable member 3 is arranged at the other end of the molding space 5 (the right end in the drawing), and the spring member 4 is arranged on the right side of the movable member 3. On one side surface (the left side surface in the drawing) of the movable member 3, a concave portion 3a for holding the right rotation shaft portion 2a of the core metal 2 is formed.
Are formed. At the time of roll forming, the cored bar 2 is disposed in a state where the left side rotating shaft 2b of the cored bar 2 is held in the recess 1a of the forming space 5, and the right side rotating shaft 2a of the cored bar 2 is movable. The movable member 3 is arranged in a state of being held in the concave portion 3a of the member 3, and the spring member 4 is arranged in a slightly contracted state so as to press the movable member 3 to the left. In this embodiment, the axial clearance of the cored bar 2 (the clearance between the right side surface of the large diameter portion 2c of the cored bar 2 and the left side surface of the movable member 3) 7 is 0 m when the movable member 3 is pressed.
The clearance 8 between the end surface of the right rotation shaft portion 2c of the cored bar 2 and the back surface of the recess 3a of the movable member 3 is set to 0.05.
It is set to mm. In a predetermined portion of the molding die as described above (that is, a space formed between the inner peripheral surface of the mold 1 and the outer peripheral surface of the large diameter portion 2c of the core metal 2 and the left side surface of the movable member 3),
HTV type silicone rubber (DY32-904U, manufactured by Toray Dow Corning) 6 was injected by the transfer injection method (see FIG. 2), and molded by press heating vulcanization. In this case, the mold 1 and the cored bar 2 thermally expand in the direction of the arrow in the figure due to the linear expansion during the heating and vulcanization, but the difference in the thermal expansion between the two is the difference between the movable member 3 and the spring member 4. Can be absorbed by the extension absorbing means. Therefore, the clearances 7 and 8 at the time of heat vulcanization can be maintained at appropriate small values.

[0019]

Comparative Example As a comparative example, the conventional example shown in FIG. 5 was used.
In this comparative example, the mold 13 and the cored bar 11 were made of the same material as that of the above-described example. And the core-
Axial clearance 16 of core metal 11 between molds is set to 0.0
It was set to 5 mm.

With respect to the above Examples and Comparative Examples, the demoldability of the molded product, the presence or absence of burrs after molding, the presence or absence of deformation of the cored bar, and the presence or absence of damage to the mold were examined, and the results are shown in Table 1 below. It was shown to. Regarding the burr, it was determined that the leakage of the rubber to the cored bar portion other than the rubber injection portion was a burr, and the mold release property was difficult even when the mold release property was deteriorated due to the burr. Further, the deformation of the cored bar after molding was judged by the scratches on the cored bar-die contact portion and the change in the deflection measurement value of the cored bar. In addition, the damage to the mold was determined to be “damaged” even for the scratches that occurred during demolding. Then, the superiority or inferiority of the durability of the mold was judged by the degree of deformation of the core metal and the damage of the mold after the molding.

[0021]

[Table 1]

As is clear from Table 1 above, the samples of the examples are the same as those of the comparative examples in all of the demoldability of the molded product, the occurrence of burrs after molding, the deformation of the cored bar, and the damage of the mold. It turns out to be better than the one.

FIG. 3 shows another embodiment of the molding die of the present invention. In this embodiment, an O-ring 9 is provided between the right side surface of the large diameter portion 2c of the cored bar 2 and the left side surface of the movable member 3. The other parts are the same as those in the above-mentioned embodiment, and the same parts are denoted by the same reference numerals. In this example, the sealing property is improved.

[0024]

As described above, according to the roll manufacturing method of the present invention, the core metal having a different material from that of the molding die is arranged in the molding die, and the elongation absorbing means is also arranged. When rubber is injected into the space formed between the inner surface of the core metal and the outer surface of the core metal, and then heat vulcanization molding is performed, the expansion and absorption means absorb the thermal expansion of the core metal in the axial direction due to the heating. I am trying. Therefore, even if the clearance at room temperature formed between the molding die and the core metal is set small (appropriately), the clearance at the time of heat vulcanization hardly changes, and the small clearance can be reduced. Can be maintained (properly). As a result, unlike the conventional example, a large force is not applied between the core metal 11 and the molding die 13 at the time of heat vulcanization, and the demoldability is reduced, the core metal 11 is deformed, the molding die 13 is damaged, and the like. The problem no longer occurs. Further, as described above, since the clearance can be set small, the occurrence of burrs can be significantly reduced, the demoldability is improved, and the deburring process is not required, resulting in material cost and processing. It is advantageous in terms of cost.
On the other hand, according to the roll forming die of the present invention, the above manufacturing method can be realized easily and efficiently. Further, in the present invention, the extension absorbing means includes a movable member that holds the end portion of the cored bar and is movable in the axial direction of the cored bar, and a spring member that urges the movable member against the cored bar. In this case, the extension absorbing means is composed of two parts, and the structure is simple. When the mold is an iron mold and the core is an aluminum cylinder, a core made of an aluminum cylinder excellent in durability, workability, etc. of the mold and having good thermal conductivity. The gold can ensure a sufficient amount of heat transfer for melting the toner. Moreover, the present invention has the above-mentioned excellent effects even though materials made of materials having greatly different linear expansion coefficients are used. Further, the core metal is a shaft body having a rotary shaft portion protruding from both end surfaces thereof, and a concave portion engaging with the rotary shaft portion is formed on the other end surface of the movable member and the other end surface of the molding space. In this case, there is an advantage that the core metal can be accurately positioned and fixed in the molding space by utilizing the rotary shaft portion and the concave portion.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a molding die used in an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing an operation of the molding die.

FIG. 3 is a sectional view showing another embodiment of the present invention.

FIG. 4 is a cross-sectional view showing a conventional example.

FIG. 5 is an explanatory diagram of a roll manufacturing method.

FIG. 6 is a sectional view showing an operation of a conventional example.

[Explanation of symbols]

 1 Mold (Mold) 2 Core Bar 3 Movable Member 4 Spring Material 5 Mold Space

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location // B29K 21:00 105: 24 705: 02 B29L 31:32

Claims (5)

[Claims] 1. A heat vulcanization molding is performed by arranging a cored bar made of a material different from that of the mold and injecting rubber into a space formed between the inner surface of the mold and the outer surface of the cored bar. A method of manufacturing a roll, wherein the core metal is provided with extension absorbing means in the molding die so as to absorb the elongation when the core metal is thermally expanded in the axial direction by the heat applied during the heat vulcanization. The method for producing a roll, wherein the above-mentioned thermal elongation is absorbed. 2. The extension absorbing means is composed of a movable member which holds an end portion of the cored bar and is movable in the axial direction of the cored bar, and a spring member which urges the movable member against the cored bar. The method for producing a roll according to claim 1. 3. The method for producing a roll according to claim 1, wherein the forming die is an iron die and the core metal is an aluminum cylinder. 4. The core metal is a shaft body having a rotary shaft portion projectingly provided on both end surfaces thereof, and a recess for holding the rotary shaft portion is formed on the other end surface of the movable member and the other end surface of the molding space. The method for producing a roll according to claim 1, wherein 5. A roll molding die for arranging a core metal in a molding space, injecting rubber into a space formed between an inner surface of the molding space and an outer surface of the core metal, and then performing heat vulcanization molding. Then, at one end side of the molding space, a movable member for gripping the axial end portion of the core metal is arranged, and a spring member for urging the movable member against the core metal is arranged. A roll forming die characterized in that