JP2016065972A - Roll for fixing device, fixing device, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a roll for a fixing device that reduces a difference in thermal expansion between the center and ends in the axial direction of an elastic layer in the roll for a fixing device.SOLUTION: There is provided a roll for a fixing device 10 that includes a cylindrical base material 12, at least one elastic layer 14 provided on the peripheral surface of the base material 2, and a plurality of continuous holes 16 provided in the longitudinal direction of the elastic layer 14, where the cross section area of the continuous holes 16 increases from the center toward the ends in the axial direction of the elastic layer 14.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a roll for a fixing device, a fixing device, and an image forming apparatus.

  In an image forming apparatus such as a copying machine or a printer using an electrophotographic system, an unfixed toner image formed on a recording medium such as recording paper is fixed by a fixing device to form an image. As a fixing device used in such an image forming apparatus, a roll / roll system including a heating roll and a pressure roll, a roll / belt system including a heating roll and a pressure belt, a belt including a heating belt and a pressure roll, There are roll methods.

  For example, in Patent Document 1, in a roll for a fixing device in which a surface coating layer is formed on a peripheral surface of a core metal via a sponge layer, the sponge layer is parallel to the longitudinal direction of the core metal and the periphery of the core metal. A fixing device roll having a large number of through holes or spiral through holes in the direction is described.

JP-A-2-282283

  An object of the present invention is to provide a fixing device roll in which a difference in thermal expansion between an axial center portion and an end portion of an elastic layer in the fixing device roll is reduced.

  The invention according to claim 1 includes a cylindrical base material, at least one elastic layer provided on a peripheral surface of the base material, and a plurality of continuous holes provided in a longitudinal direction of the elastic layer. And a roll for a fixing device in which a cross-sectional area of the continuous hole increases from an axial center to an end of the elastic layer.

  The invention according to claim 2 is the fixing device roll according to claim 1, wherein the cross-sectional shape of the continuous hole in the axial direction is reduced from the radial outer surface side to the inner surface side of the elastic layer. is there.

  According to a third aspect of the present invention, there is provided a fixing device comprising the fixing device roll according to the first or second aspect.

  According to a fourth aspect of the present invention, there is provided an image forming apparatus comprising the fixing device according to the third aspect.

  According to the first aspect of the present invention, compared to the case where the cross-sectional area of the continuous hole in the elastic layer does not increase from the central portion in the axial direction of the elastic layer toward the end portion, the central portion and the end portion of the elastic layer There is provided a roll for a fixing device in which the difference in thermal expansion of the part is reduced.

  According to the invention which concerns on Claim 2, compared with the case where the cross-sectional shape of the axial direction of the said continuous hole is not small toward the inner surface side from the outer surface side of the radial direction of an elastic layer, the center part of an elastic layer and The difference in thermal expansion at the end is reduced, and the durability of the elastic layer is improved.

  According to the invention of claim 3, the elastic layer has an elastic layer as compared with the case where the cross-sectional area of the continuous hole in the elastic layer of the fixing device roll does not increase from the central portion to the end in the axial direction of the elastic layer. There is provided a fixing device including a fixing device roll in which a difference in thermal expansion between a central portion and an end portion of the fixing device is reduced.

  According to the fourth aspect of the present invention, the elastic layer has an elastic layer as compared with the case where the cross-sectional area of the continuous hole in the elastic layer of the fixing device roll does not increase from the axial center to the end of the elastic layer. There is provided an image forming apparatus including a fixing device roll in which a difference in thermal expansion between a central portion and an end portion of the fixing device is reduced.

FIG. 3 is a schematic cross-sectional view perpendicular to the axis showing an example of a fixing device roll according to an exemplary embodiment of the present invention. FIG. 2 is a schematic cross-sectional view in the axial direction showing an example of a fixing device roll according to an embodiment of the present invention. FIG. 6 is a schematic cross-sectional view in the axial direction showing another example of a fixing device roll according to an embodiment of the present invention. FIG. 6 is a schematic cross-sectional view perpendicular to an axis showing another example of a fixing device roll according to an embodiment of the present invention. 1 is a schematic cross-sectional view illustrating an example of a fixing device according to an embodiment of the present invention. 1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to an embodiment of the present invention. It is the schematic of the metal mold | die and cap used in the Example. It is the schematic of the metal mold | die equipped with the cap in the Example. It is a schematic sectional drawing of the axial direction which shows the roll for fixing devices used by the comparative example. It is a figure which shows the number of continuous paper passing in Example 1 and Comparative Example 1, and the thermal expansion step between the paper passing portion and the non-paper passing portion of the elastic layer. It is a figure which shows the thermal expansion level | step difference of the axial direction of the elastic layer in an Example and a comparative example.

  Embodiments of the present invention will be described below. This embodiment is an example for carrying out the present invention, and the present invention is not limited to this embodiment.

<Fixing device roll>
FIG. 1 is a schematic cross-sectional view perpendicular to the axis showing an example of a fixing device roll according to an embodiment of the present invention, and FIG. 2 shows an example of a fixing device roll according to an embodiment of the present invention. It is a schematic sectional drawing of an axial direction.

  As shown in FIGS. 1 and 2, the fixing device roll 10 is provided in the longitudinal direction of the cylindrical base material 12, the elastic layer 14 provided on the outer peripheral surface of the base material 12, and the elastic layer 14. A plurality of continuous holes 16, and the cross-sectional area of the continuous holes 16 increases from the axial center to the end of the elastic layer 14. The configuration of the fixing device roll 10 is not limited to the layer configuration shown in FIGS. 1 and 2, and a release layer may be provided on the outer peripheral surface of the elastic layer 14. A layer (adhesive layer) may be provided.

  In a fixing device such as a roll / roll system having a heating roll and a pressure roll in an image forming apparatus, and a belt / roll system having a pressure roll and a heating belt, for example, an additional sheet that becomes a non-sheet passing portion during continuous sheet passing. When the temperature at the end of the pressure roll in the axial direction rises, the amount of thermal expansion of the non-sheet-passing part is larger than the center part in the axial direction of the pressure roll that becomes the paper passing part, and the pressure roll is at room temperature As compared with the above, the difference in the roll diameter between the axial end portion and the central portion of the pressure roll may be increased. This may cause problems such as streaking of the sheet in the width direction of the sheet or a reduction in durability of the pressure roll due to an increase in the surface pressure at the axial end of the pressure roll. There is. The inventors of the present invention provide a plurality of continuous holes in the longitudinal direction of the elastic layer of the fixing device roll, and change the cross-sectional area in the axial direction. Specifically, the cross-sectional area of the continuous holes is changed. It was found that the difference in thermal expansion of the roll diameter between the end portion and the center portion during continuous paper passing or the like is reduced by increasing the elastic layer from the center portion toward the end portion in the axial direction. This makes it easier for the heat in the elastic layer on the end side to be released, compared to the case where the cross-sectional area of the continuous hole in the elastic layer does not increase from the axial center to the end of the elastic layer, Moreover, it is considered that the volume that thermally expands decreases.

  As shown in FIGS. 1 and 2, the continuous hole 16 is a hole provided continuously from the end of the elastic layer 14 toward the center. The cross-sectional shape of the continuous hole 16 is not particularly limited as long as the cross-sectional area of the pores increases from the axial center to the end of the elastic layer. The cross-sectional shape of the continuous hole 16 is, for example, a circular shape as shown in FIG. 1, but is not limited thereto, and may be a polygonal shape such as a triangular shape or a quadrangular shape, an elliptical shape, a fan shape, or the like. Moreover, about the some continuous hole 16, all may have the same cross-sectional shape, and may differ. The cross-sectional shape of one continuous hole 16 may change in the axial direction.

  The ratio of the cross-sectional area of the maximum portion of the end portion of the continuous hole 16 to the cross-sectional area of the minimum portion of the central portion only needs to increase from the central portion in the axial direction of the elastic layer 14 toward the end portion, and is particularly limited. There is no. The ratio of the cross-sectional area of the end portion of the continuous hole 16 to the cross-sectional area of the central portion (the cross-sectional area of the end portion / the cross-sectional area of the central portion) is, for example, in the range of 1 to 100.

  The size of the maximum cross-sectional area of each continuous hole 16 at the end of the elastic layer 14 is not particularly limited. For example, the cross-sectional area in the axial direction of the elastic layer 14 is 1/1000 or more and 1/100 or less. It is about the range. When the size of the maximum cross-sectional area of each continuous hole 16 is less than 1/1000 of the cross-sectional area in the axial direction of the elastic layer 14, it becomes difficult to obtain the effect of heat release, and exceeds 1/100. And the function of the elastic layer 14 is impaired by the influence of the continuous holes 16, and it may be difficult to ensure the nip width between the heating roll and the like.

  The continuous hole 16 does not need to penetrate from one end of the elastic layer to the other end as shown in FIG. 2, or penetrates from one end to the other end of the elastic layer as shown in FIG. Also good.

  The length in the axial direction of the elastic layer of the continuous hole 16 may be set so that, for example, at least the continuous hole 16 exists in a portion that becomes a non-sheet passing portion when using the assumed minimum recording medium.

  The number of the continuous holes 16 and the installation position in the elastic layer 14 are set so that the plurality of continuous holes 16 are spaced apart from the outer surface of the elastic layer 14 in advance so that the elastic layer 14 can obtain a heat releasing effect as uniformly as possible. It is preferable to provide it at equal angular intervals along the axial direction of the substrate 12.

  As shown in FIG. 4, the cross-sectional shape in the axial direction of the continuous hole 16 may be a triangle or the like, and may be made smaller from the radially outer surface side to the inner surface side of the elastic layer 14. Compared to the case where the axial sectional shape of the continuous hole 16 is not reduced from the radial outer surface side to the inner surface side of the elastic layer 14, the resistance to stress applied on the inner surface side (base material 12 side) is stronger. It is considered that the durability of the elastic layer is improved. In addition, since the cross-sectional shape in the axial direction of the continuous hole 16 is reduced from the radially outer surface side to the inner surface side of the elastic layer 14, the effect of heat release on the outer surface side of the elastic layer 14 is easily obtained. It is considered that the difference in thermal expansion between the central portion and the end portion of the elastic layer is further reduced.

  With the configuration as described above, a fixing device roll is provided in which the workability of the elastic layer and the function of the elastic layer are maintained, and the difference in thermal expansion between the central portion and the end portion of the elastic layer is reduced.

  Examples of the base material 12 include aluminum, SUS (stainless steel), SUM (sulfur and sulfur composite free-cutting steel material), and a cylindrical body and columnar body made of iron or the like. The outer diameter and wall thickness of the base material 12 are, for example, usually 15 mm to 100 mm in outer diameter. For example, the thickness is 5 mm or more in the case of aluminum, and 3 mm or more in the case of SUS, SUM or iron. It is.

  Examples of the material of the elastic layer 14 include silicone rubber and fluorine rubber having a hardness of about 10 ° to 80 ° (JIS-A). The elastic layer 14 may be a foam having a foam structure.

  The elastic layer 14 may contain hollow particles such as hollow glass particles (glass balloons). Since the glass balloon has a hollow inside, the glass balloon is difficult to thermally expand. By containing the glass balloon, the elastic layer 14 is hardly thermally expanded.

  The median diameter of hollow particles such as glass balloons is, for example, in the range of 1 μm to 500 μm.

  The content of hollow particles such as glass balloons is, for example, in the range of 5 vol% or more and 60 vol% or less with respect to the elastic layer 14.

  The thickness of the elastic layer 14 is, for example, 2 mm or more and 10 mm or less, preferably 3 mm or more and 10 mm or less.

  Examples of the material of the release layer that may be provided as necessary include a fluororesin. Examples of the fluororesin include tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), and the like. Examples of the release layer material include composite materials of these fluororesins, and those obtained by blending these resins with fillers (for example, carbon, alumina, barium sulfate, etc.).

  The thickness of the release layer is, for example, 10 μm or more and 500 μm or less, preferably 20 μm or more and 200 μm or less. As the release layer, for example, a fluororesin tube such as a PFA tube having this thickness may be coated.

  Examples of a material for the primer layer (adhesive layer) that may be provided as necessary include Toray Dow Corning, Primer DY39-051A / B, and the like.

<Fixing device>
FIG. 5 is a schematic configuration diagram illustrating the fixing device according to the present embodiment. As shown in FIG. 5, for example, the fixing device 20 according to the present embodiment is in contact with a heating roll 22 (first rotating body) having a heat source 32 (for example, a halogen heater) and an outer peripheral surface of the heating roll 22. The fixing roll 10 (second rotating body) is provided as the pressure roll 30 disposed separately. The pressure roll 30 is disposed in contact with the heating roll 22 so that its axial direction is along the axial direction of the heating roll 22. Here, the heating roll 22 is a roll that is driven to rotate, and the pressure roll 30 is disposed in contact with the outer peripheral surface of the heating roll 22, so that the pressure roll 30 is accompanied by the rotation of the heating roll 22. Rotate.

  The heating roll 22 may have a known configuration, for example, a cylindrical base 24 (for example, a SUS base, aluminum or an alloy base thereof), and an elastic layer provided on the outer peripheral surface of the base 24. 26 (for example, a silicone rubber layer or a fluorine rubber layer) and a release layer 28 provided on the elastic layer 26.

  In the fixing device 20 according to the present embodiment, the heating roll 22 and the pressure roll 30 are arranged in contact with each other, and the heating roll 22 is rotationally driven. Then, the recording medium on which the unfixed toner image is formed is nipped between both rolls and conveyed. At this time, the toner image is melted by the heat transmitted from the heating roll 22, and the toner image is pressed against the surface of the recording medium by the pressure between the two rolls to fix the toner image.

  Further, in the fixing device 20 according to the present embodiment, the heating roll 22 is employed as the first rotating body, the pressure roll 30 is employed as the second rotating body, and the fixing apparatus roll 10 according to the present embodiment is employed as the pressure roll 30. However, the present invention is not limited to this, but a heating belt is used as the first rotating body to be rotated, a pressure roll is used as the second rotating body, and the above-mentioned book is used as the pressure roll. A fixing device of a so-called belt-roll system to which the fixing device roll 10 according to the embodiment is applied may be used.

<Image forming apparatus>
The image forming apparatus according to the present embodiment is not particularly limited as long as it includes the fixing device roll 10 according to the present embodiment. The image forming apparatus includes, for example, an image carrier, a charging unit that charges the surface of the image carrier, a latent image forming unit that forms an electrostatic latent image on the surface of the image carrier, and a surface formed on the surface of the image carrier. Developing means for developing the electrostatic latent image using a developer to form a toner image, transfer means for transferring the developed toner image to a recording medium, and fixing the toner image transferred to the recording medium And a fixing unit having the fixing device roll 10 according to the present embodiment. The image forming apparatus according to the present exemplary embodiment may include an image carrier cleaning unit that removes residual toner and the like remaining on the surface of the image carrier after the transfer and cleans it as necessary.

  A schematic configuration of an example of the image forming apparatus according to the present embodiment is shown in FIG. 6 and the configuration will be described. The image forming apparatus 1 includes a photosensitive member 54 as an image carrier on which an electrostatic latent image is formed, a charging device 50 as a charging unit that charges the surface of the photosensitive member 54, and laser light or reflected light of a document. An exposure device 52 as a latent image forming unit that forms an electrostatic latent image on the surface of the photoreceptor 54, and a developing unit that forms a toner image by attaching toner to the electrostatic latent image formed on the surface of the photoreceptor 54. A developing device 56, a transfer roll 58 as a transfer means for transferring a toner image on the surface of the photoconductor 54 to a recording sheet 62 as a recording medium, and the surface of the photoconductor 54, and after the transfer, the photoconductor 54 A cleaning blade 60 as an image carrier cleaning means for removing residual toner and the like remaining on the surface of the recording medium, and a heating roll 22 as a fixing means for fixing the toner image transferred to the recording medium. And a fixing device 20 having a pressure roll 30 is a fixing device for a roll 10. In the image forming apparatus 1, a charging device 50, an exposure device 52, a developing device 56, a transfer roll 58, and a cleaning blade 60 are arranged in this order around the photoreceptor 54. In FIG. 6, the description of functional units normally required in other electrophotographic processes is omitted.

  An operation of the image forming apparatus 1 according to the present embodiment will be described.

  First, the surface of the photoreceptor 54 is charged by the charging device 50 (charging process). Next, light is applied to the surface of the photoconductor 54 by the exposure device 52, and the charged charges in the irradiated portion are removed, and an electrostatic latent image (electrostatic charge image) is formed according to the image information ( Latent image forming step). Thereafter, the electrostatic latent image is developed by the developing device 56, and a toner image is formed on the surface of the photoreceptor 54 (developing process). For example, in the case of a digital electrophotographic copying machine using an organic photoconductor as the photoconductor 54 and using a laser beam as the exposure device 52, the surface of the photoconductor 54 is given a negative charge by the charging device 50, and the laser beam A digital latent image is formed in the form of dots by light, and toner is applied to a portion irradiated with the laser beam by the developing device 56 to make a visible image. In this case, a negative bias is applied to the developing device 56. Next, the recording paper 62 as a recording medium is superimposed on the toner image by the transfer roll 58, and the charge opposite to the toner is given to the recording paper 62 from the back side of the recording paper 62, and the toner image is recorded by electrostatic force. Transferred onto the paper 62 (transfer process). The transferred toner image is subjected to heat and pressure in a fixing device 20 having a heating roll 22 and a pressure roll 30 as fixing means, and is fused and fixed to the recording paper 62 (fixing step). On the other hand, toner and other residues that remain on the surface of the photoreceptor 54 without being transferred are removed by the cleaning blade 60 (image carrier cleaning step). One cycle is completed in a series of processes from the charging step to the image carrier cleaning step. In FIG. 6, the toner image is directly transferred to the recording paper 62 by the transfer roll 58, but may be transferred via an intermediate transfer member such as an intermediate transfer belt.

  For example, a charging device such as a corotron as shown in FIG. 6 is used as the charging device 50 as the charging means, but a conductive or semiconductive charging roll may be used. A contact charger using a conductive or semiconductive charging roll may apply a direct current to the photosensitive member 54 or may apply an alternating current superimposed thereon. For example, such a charging device 50 charges the surface of the photoreceptor 54 by generating a discharge in a minute space near the contact portion with the photoreceptor 54. Normally, it is charged to −300V or more and −1000V or less. The conductive or semiconductive charging roll may have a single layer structure or a multiple structure. Further, a mechanism for cleaning the surface of the charging roll may be provided.

  The photoreceptor 54 has a function of forming at least an electrostatic latent image (electrostatic charge image). In the electrophotographic photosensitive member, an undercoat layer, a charge generation layer containing a charge generation material, and a charge transport layer containing a charge transport material are formed in this order on the outer peripheral surface of a cylindrical conductive substrate as necessary. It is a thing. The order of stacking the charge generation layer and the charge transport layer may be reversed. These are laminated photoconductors in which a charge generation material and a charge transport material are contained in separate layers (charge generation layer, charge transport layer), but both the charge generation material and the charge transport material are the same. A single-layer type photoreceptor included in the above layer may be used, and a laminated photoreceptor is preferable. Further, an intermediate layer may be provided between the undercoat layer and the photosensitive layer. Further, a protective layer may be provided on the photosensitive layer. Further, other types of photosensitive layers such as an amorphous silicon photosensitive film may be used without being limited to the organic photoreceptor.

  The exposure device 52 is not particularly limited. For example, a laser optical system that exposes a light source such as semiconductor laser light, LED (Light Emitting Diode) light, and liquid crystal shutter light on the surface of the photoreceptor 54 in a desired image-like manner, Examples include optical system devices such as LED arrays.

  The developing unit has a function of developing the electrostatic latent image formed on the photoreceptor 54 with a one-component developer or a two-component developer containing an electrostatic charge image developing toner to form a toner image. Such a developing device is not particularly limited as long as it has the above-described function, and may be appropriately selected according to the purpose. It may be a thing. For example, as shown in FIG. 6, a developer having a function of attaching toner for developing an electrostatic charge image to the photoreceptor 54 using the developing device 56, or a development having a function of attaching the toner to the photoreceptor 54 using a brush or the like. And a known developing device.

  As a transfer device as a transfer means, for example, a charge opposite in polarity to the toner is applied to the recording paper 62 from the back side of the recording paper 62, and the toner image is transferred to the recording paper 62 by electrostatic force, or as shown in FIG. A transfer roll and a transfer roll pressing device using a conductive or semiconductive roll or the like that directly contacts and transfers the surface of the recording paper 62 via the recording paper 62 may be used. A direct current may be applied to the transfer roll as a transfer current applied to the image carrier, or an alternating current may be applied in a superimposed manner. The transfer roll may be arbitrarily set according to the width of the image area to be charged, the shape of the transfer charger, the opening width, the process speed (circumferential speed), and the like. Further, a single layer foam roll or the like is suitably used as a transfer roll for cost reduction. The transfer method may be a method of transferring directly to the recording paper 62 or a method of transferring to the recording paper 62 via an intermediate transfer member.

  A known intermediate transfer member may be used as the intermediate transfer member. Materials used for the intermediate transfer member include polycarbonate resin (PC), polyvinylidene fluoride (PVDF), polyalkylene phthalate, PC / polyalkylene terephthalate (PAT) blend material, ethylene tetrafluoroethylene copolymer (ETFE) / PC, ETFE / PAT, PC / PAT blend materials, and the like can be mentioned. From the viewpoint of mechanical strength, an intermediate transfer belt using a thermosetting polyimide resin is preferable.

  The image carrier cleaning means may be selected as appropriate as long as it removes residual toner on the image carrier and cleans it, and employs a blade cleaning method, a brush cleaning method, a roll cleaning method, or the like. . Among these, it is preferable to use a cleaning blade. Examples of the material for the cleaning blade include urethane rubber, neoprene rubber, and silicone rubber. Among them, it is particularly preferable to use a polyurethane elastic body because of its excellent wear resistance.

  The fixing device 20 as a fixing unit fixes the toner image transferred to the recording paper 62 by heating, pressing, or heating and pressing, and includes the fixing device roll 10 according to the present embodiment. There is no particular limitation.

  Examples of the recording paper 62 that is a recording medium to which the toner image is transferred include plain paper, OHP sheets, and the like used in electrophotographic copying machines and printers. In order to further improve the smoothness of the image surface after fixing, it is preferable that the surface of the transfer material is as smooth as possible. For example, coated paper in which the surface of plain paper is coated with resin, art paper for printing, etc. Preferably used.

  The respective configurations of the image forming apparatus according to the present embodiment are not limited to these, and conventionally known configurations may be applied as the respective configurations of the electrophotographic image forming apparatus. That is, conventionally known image holding members, charging means, latent image forming means, developing means, transfer means, image holding member cleaning means, charge eliminating means, paper feeding means, conveying means, image control means, and the like as required. Is appropriately adopted. These configurations are not particularly limited in the present embodiment.

  The image forming apparatus according to the present embodiment has been described with respect to a system that directly transfers a toner image formed on an electrophotographic photosensitive member to a recording medium. However, the present invention is not limited to this, and the toner image formed on the electrophotographic photosensitive member is not limited thereto. A well-known configuration such as an intermediate transfer type apparatus that transfers the image to a recording medium via an intermediate transfer body or a tandem type apparatus in which a plurality of electrophotographic photosensitive members are provided in series with the intermediate transfer body may be applied.

  The image forming apparatus according to the present embodiment can be applied to an image forming apparatus such as a copying machine, a printer, or a facsimile.

  Hereinafter, although an example and a comparative example are given and the present invention is explained more concretely in detail, the present invention is not limited to the following examples.

<Example 1>
Silicone rubber-containing liquid manufactured by Shin-Etsu Chemical Co., Ltd. (KE-1950-10A / B, material viscosity A / B 55Pa · s, specific gravity 1.01, hardness after curing 14 °, Type A) Glass balloons (manufactured by 3M, Glass Bubbles K37, median diameter 45 μm, 90% residual pressure strength 21 MPa, specific gravity 0.37) were mixed at a rate of 25 vol%, and planetary mixers (manufactured by Inoue Manufacturing Co., Ltd., PLM). The mixture was stirred and kneaded for 30 minutes in -5). Thereafter, liquid A and liquid B were weighed out and mixed in equal amounts, and again stirred and kneaded in a planetary mixer for 30 minutes to obtain a glass balloon-dispersed silicone rubber material in which glass balloons were dispersed substantially uniformly.

[Roll molding]
A primer agent (Primer DY39-051A / B, manufactured by Toray Dow Corning Co., Ltd.) was applied to a silicone rubber coating portion of a cylindrical base material (material SUM) having a diameter of 18 mm, and air-dried for 30 minutes. Thereafter, heat treatment was performed in an oven at 150 ° C. for 30 minutes. Insert a conductive PFA tube (manufactured by Gunze Co., Ltd.) having a diameter of 27 mm, a thickness of 0.05 mm, and a length of 500 mm into a cylindrical metal mold having an outer diameter of 30 mm, an inner diameter of 28 mm, and a length of 400 mm as shown in FIG. Then, both ends were folded back at the end of the mold, and vacuum suction was performed between the mold and the conductive PFA tube, and the tube was brought into close contact with the inner surface of the mold. A primer agent (Primer DY39-125A / B, manufactured by Toray Dow Corning Co., Ltd.) is applied to the inner surface of the tube, air-dried for 10 minutes, and then the base material is inserted into the mold. A cap mold was attached to the substrate, and a base material was set in the center of the mold. At this time, 12 conical pins (maximum diameter 0.85 mm, length 130 mm) as shown in FIG. 7 are equidistantly spaced along the axial direction of the base material on the inner surfaces of the cap molds attached to both ends. The provided one was used. This pin forms a continuous hole in the elastic layer. The glass balloon-dispersed silicone rubber material prepared above is placed between the conductive PFA tube brought into close contact with the inner surface of the mold by vacuum suction from the LSR (liquid silicone rubber) inlet of FIG. 7 and the base material set in the center. Injected. Thereafter, the mold was vulcanized for 1 hour in a 150 ° C. oven while being rotated horizontally at a speed of 10 rpm, thereby performing primary vulcanization of silicone rubber. The roll was removed from the mold, and the excess tube part and rubber burr part were cut at both ends so that the silicone rubber width was 350 mm. Secondary vulcanization was performed in an oven at 200 ° C. for 4 hours to obtain a roll for a fixing device as shown in FIG.

<Example 2>
As a cap mold to be mounted on both ends of the mold, 12 conical pins (maximum diameter 0.85 mm, minimum diameter 0.2 mm, length 185 mm) are provided at equal angular intervals along the axial direction of the substrate. Except for the use, a roll was molded in the same manner as in Example 1 to obtain a roll for a fixing device as shown in FIG.

<Example 3>
12 caps with triangular pyramids (maximum side 0.8mm, minimum side 0.2mm, length 130mm) provided at equiangular intervals along the axial direction of the substrate as cap molds attached to both ends of the mold A roll was formed in the same manner as in Example 1 except that the fixing device roll shown in FIG. 4 was obtained.

<Comparative Example 1>
In Example 1, a roll was formed in the same manner as in Example 1 except that the shape of the pin provided on the inner surface of the cap mold attached to both ends was a columnar shape (diameter 0.85 mm, length 185 mm). A roll for a fixing device as shown in 9 was obtained. In the fixing device roll of FIG. 9, a cylindrical base material 82, an elastic layer 84 provided on the outer peripheral surface of the base material 82, a plurality of continuous holes 86 provided in the longitudinal direction of the elastic layer 84, The cross-sectional area of the continuous hole 86 does not increase from the central portion in the axial direction of the elastic layer 14 toward the end portion, and the cross-sectional area of the central portion and the cross-sectional area of the end portion are substantially the same.

<Comparative Example 2>
In Example 1, a roll was molded in the same manner as in Example 1 except that no cap was provided on the cap mold attached to both ends to obtain a fixing device roll.

[Evaluation]
The obtained sample roll for the fixing device is mounted as a pressure roll on a bench machine using an Apeos C3370 fixing device manufactured by Fuji Xerox Co., Ltd., and continuously runs on recording paper (J paper, color copy paper manufactured by Fuji Xerox Co., Ltd.). In this case, the number of continuous sheets passed until the streaky sheet deformation occurred in the sheet width direction and the thermal expansion step of the fixing roll between the non-sheet passing section and the sheet passing section were evaluated. Note that the fixing device of the Apeos C3370 is a belt-roll system unlike the roll-roll system shown in FIG. For the thermal expansion step, the distance between the sheet passing portion and the pressure roll surface of the non-sheet passing portion was measured simultaneously using a laser displacement meter (manufactured by KEIENCE, LK30 type), and the difference was defined as the thermal expansion step. FIG. 10 shows the number of continuous sheets passed in Example 1 and Comparative Example 1, and the thermal expansion step (unit: μm) between the sheet passing portion and the non-sheet passing portion of the elastic layer, and FIG. The thermal expansion step (unit: μm) in the direction (unit: mm) is shown. The results are shown in Table 1.

  As described above, when the fixing device roll of the example was used, the difference in thermal expansion between the central portion and the end portion in the axial direction of the elastic layer was reduced as compared with the case where the fixing device roll of the comparative example was used.

  DESCRIPTION OF SYMBOLS 1 Image forming apparatus 10,80 Roll for fixing devices, 12,82 Base material, 14,84 Elastic layer, 16,86 Continuous hole, 20 Fixing device, 22 Heating roll, 24 Base material, 26 Elastic layer, 28 Mold release Layer, 30 pressure roll, 32 heat source, 50 charging device, 52 exposure device, 54 photoconductor, 56 developing device, 58 transfer roll, 60 cleaning blade, 62 recording medium.

Claims (4)

A cylindrical substrate;
At least one elastic layer provided on the peripheral surface of the substrate;
A plurality of continuous holes provided in the longitudinal direction of the elastic layer;
Have
The fixing device roll according to claim 1, wherein a cross-sectional area of the continuous hole is increased from an axial center portion to an end portion of the elastic layer.   2. The fixing device roll according to claim 1, wherein a cross-sectional shape of the continuous hole in an axial direction becomes smaller from a radially outer surface side to an inner surface side of the elastic layer.   A fixing device comprising the roll for a fixing device according to claim 1.   An image forming apparatus comprising the fixing device according to claim 3.