JP2007147865A - Tubular belt member, fixing device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tubular belt member in which lubricant is not easily leaked to the outer peripheral side even when the tubular belt member is not rotated and to provide a fixing device and an image forming apparatus, in which fine image formation is maintained. <P>SOLUTION: The tubular belt member is provided with a belt body having a tubular shape and a plurality of ridges arranged on the inner periphery of the belt body, extended in a direction inclined to the circumferential direction of the inner periphery on the inner periphery and spreading both bases in a direction intersecting with the extending direction so that the first base turned to the edge side of the belt body out of both the bases has a shaper slant as compared with the second base turned to the inside of the belt body. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a belt tubular body formed of a belt formed in a tubular shape, a fixing device that fixes an unfixed toner image, and an image forming apparatus that forms an image formed of a fixed toner image on a recording medium.

In recent years, image forming apparatuses such as printers and copiers have become widespread. Among image forming apparatuses, an image forming apparatus adopting an electrophotographic method includes a fixing device that applies heat and pressure to a recording medium. In such an image forming apparatus, an unfixed toner image is formed on the recording medium. After the process of forming the image is performed, the unfixed toner image is fixed to the recording medium by applying heat and pressure to the unfixed toner image using a fixing device. The fixing device includes a heating roll that rotates while generating heat, and a belt tubular body that rotates following the rotation of the heating roll while circumscribing the heating roll in order to perform such heating and pressure treatment, There is a fixing device that employs a system in which heat and pressure are applied to an unfixed toner image on a recording medium by passing a recording medium having an unfixed toner image between the heating roll and the belt tubular body. Exists. In such a fixing device, a lubricant such as silicon oil is applied to the inner peripheral surface (the surface opposite to the surface in contact with the heating roll) of the belt tubular body so that the belt tubular body rotates smoothly. May be applied. When a lubricant is used, the lubricant wraps around from the edge of the belt tubular body to the outer peripheral surface side of the belt tubular body, causing slip between the belt tubular body and the heating roll, or contacting the recording medium. Recently, a problem such as creating a stain may occur. Therefore, a plurality of grooves are provided on the inner peripheral surface of the belt tubular body, and when the belt tubular body is driven to rotate, the lubricant is placed on the inner peripheral surface of the belt tubular body. A fixing device designed to prevent the belt tubular body from exiting from the edge of the belt tubular body by facilitating the flow toward the central portion of the inner peripheral surface of the belt tubular body along the groove of the belt is proposed (for example, patents). Reference 1).
JP 2005-3781 A

  However, in the above fixing device, when the belt tubular body is driven to rotate, it becomes difficult for the lubricant to come out from the edge of the belt tubular body, but when the belt tubular body is not driven to rotate, the center of the inner peripheral surface of the belt tubular body is reduced. Since no force for flowing the lubricant toward the portion is generated, the lubricant may go around from the edge of the belt tubular body to the outer peripheral surface side of the belt tubular body. When the fixing process is performed in such a state, there arises a problem that slip occurs between the belt tubular body and the heating roll, and a problem that the lubricant is stained on the recording medium, which hinders image formation.

  In view of the above circumstances, the present invention provides a belt tubular body in which the lubricant is less likely to leak to the outer peripheral surface side even when the belt tubular body is not rotationally driven, a fixing device that maintains good image formation, and an image forming apparatus. Objective.

In order to achieve the above object, the belt tubular body of the present invention comprises:
A belt body having the shape of a tube;
In the direction intersecting with the extending direction, which is provided on the inner peripheral surface of the belt body and extends in a direction inclined with respect to the circumferential direction of the inner peripheral surface on the inner peripheral surface. Both hems are widened, and the first hem of the two hems facing the edge of the belt body has a ridge that is steeper than the second hem facing the belt body. It is characterized by.

  Generally, when a liquid such as a lubricant adheres to the inner peripheral surface of the belt tubular body, the attached liquid tends to spread along the inner peripheral surface of the belt tubular body.

In the belt tubular body of the present invention, in the shape of a plurality of protrusions provided on the inner peripheral surface of the belt tubular body, the hem facing the edge of the belt body is steeper than the skirt facing the inside of the belt body. Therefore, the liquid adhering to the inner peripheral surface of the belt tubular body tends to spread inside the belt main body. For this reason, the liquid adhering on the inner peripheral surface of the belt tubular body hardly leaks from the edge of the belt tubular body to the outer peripheral surface side.
Further, in the belt tubular body of the present invention, “as the ridge, a plurality of lines are provided side by side in a first region along the edge of the belt main body on the one end side of the tube on the inner peripheral surface of the belt main body. A first protrusion extending on the inner peripheral surface in a direction inclined with respect to the circumferential direction of the inner peripheral surface, and the other of the inner peripheral surface of the belt body with respect to the one end side of the tube. On the inner peripheral surface, a plurality of which are provided side by side in the second region along the edge of the belt body on the end side, the direction in which the first protrusion is inclined with respect to the rotation direction is opposite to the direction of the rotation. A form of “having a second protrusion extending in a direction inclined with respect to the circumferential direction” is a preferable form.

  With such a configuration, when the belt tubular body rotates, the liquid adhering to the inner peripheral surface of the belt tubular body flows between the first protrusions and the second protrusions, so that A direction of rotation that tends to gather near the center appears. By rotating the belt tubular body in this rotational direction, a state in which the liquid attached on the inner peripheral surface is difficult to leak to the outer peripheral surface side is realized.

  Moreover, in the belt tubular body of the present invention, a form in which “the second skirt is more than three times as wide as the first skirt” is a preferred form.

  When the shape of the ridge is the above shape, the tendency of the liquid adhering to the inner peripheral surface of the belt tubular body to spread toward the inner side of the belt main body becomes significant. For this reason, the belt tubular body in which the second hem spreads more than three times the spread of the first skirt becomes a belt tubular body in which the liquid adhering to the inner peripheral surface is more difficult to leak to the outer peripheral surface side.

In order to achieve the above object, the fixing device of the present invention comprises:
In a fixing device for fixing an unfixed toner image,
A rotating member that rotates;
A belt tubular body that circumscribes the rotating member and is driven to rotate. A belt main body having a tube shape, and an inner peripheral surface of the belt main body, and a belt main body on one end side of the pipe along the edge of the belt main body. A plurality of lines are arranged in one area. The hem extends on the inner peripheral surface in a direction inclined with respect to the circumferential direction of the inner peripheral surface, and both hems extend in a direction intersecting the extending direction. A belt tubular body having a ridge whose first hem facing the edge side of the belt main body of the both hems is a steep slope than the second hem facing the inner side of the belt main body;
By pressing the belt tubular body against the rotating member from the inside of the belt tubular body, a nip portion where the rotating member and the belt tubular body are in contact is formed, and the unfixed toner image is formed on the nip portion. And a pressing portion for fixing the unfixed toner image onto the recording medium when the carried recording medium passes.

  Since the fixing device of the present invention includes the belt tubular body described above, the liquid adhering to the inner peripheral surface of the belt tubular body is unlikely to leak from the edge of the belt tubular body to the outer peripheral surface side. For this reason, the above-mentioned slip and stain are prevented, and good image formation is maintained.

  In the fixing device of the present invention, “the rotating member includes a cored bar, an elastic layer that overlaps the peripheral surface of the cored bar, a release layer that further overlaps the elastic layer, and both ends of the rotating member. And a cover that covers the end of the elastic layer ”is a preferable embodiment.

  When a liquid such as a lubricant wraps around the outer peripheral surface side of the belt tubular body, it may come into contact with the elastic layer to swell the elastic layer, resulting in uneven pressure distribution in the nip portion.

  By the form provided with said cover, the liquid which wraps around to the outer peripheral surface side of a belt tubular body is prevented from contacting an elastic layer.

  Further, in the fixing device of the present invention, a form of “equipped with an oil absorbing member that contacts the outer peripheral surface of the belt tubular body and removes oil on the outer peripheral surface” is a preferable mode.

  With such a configuration, oil such as a lubricant that has oozed out to the outer peripheral surface side of the belt tubular body is absorbed by the oil absorbing member. Therefore, it is possible to suppress the toner image fixing process from being affected by the exuded oil.

In order to achieve the above object, an image forming apparatus of the present invention comprises:
In an image forming apparatus for forming an image composed of a fixed toner image on a recording medium,
A toner image forming unit for forming an unfixed toner image on the recording medium;
A rotating member that rotates;
A belt tubular body that circumscribes the rotating member and is driven to rotate. A belt main body having a tube shape, and an inner peripheral surface of the belt main body, and a belt main body on one end side of the pipe along the edge of the belt main body. A plurality of lines are arranged in one area. The hem extends on the inner peripheral surface in a direction inclined with respect to the circumferential direction of the inner peripheral surface, and both hems extend in a direction intersecting the extending direction. A belt tubular body having a ridge whose first hem facing the edge side of the belt main body of the both hems is a steep slope than the second hem facing the inner side of the belt main body;
By pressing the belt tubular body against the rotating member from the inside of the belt tubular body, a nip portion where the rotating member and the belt tubular body are in contact is formed, and the nip portion is formed by the toner image forming portion. And a pressing portion for fixing the unfixed toner image on the recording medium when the recording medium carrying the formed unfixed toner image passes therethrough.

  Since the image forming apparatus of the present invention includes the belt tubular body described above, the liquid adhering to the inner peripheral surface of the belt tubular body is less likely to leak from the edge of the belt tubular body to the outer peripheral surface side. For this reason, the above-mentioned slip and stain are prevented, and good image formation is maintained.

  According to the present invention, even when the belt tubular body is not rotationally driven, the lubricant hardly leaks to the outer peripheral surface side, and good image formation is maintained.

  Hereinafter, embodiments of the present invention will be described.

  FIG. 1 is an overall configuration diagram showing an embodiment of an image forming apparatus of the present invention.

The image forming apparatus 1000 is a monochrome double-sided output printer that employs an electrophotographic system. The image forming apparatus 1000, a photoreceptor of multilayer type electrophotographic method, a photosensitive member 3 rotates in the arrow B ₁ direction in the figure, the contact type for charging the photosensitive member while contacting the photoreceptor 3 A laser beam is emitted toward the charger 2 and the photosensitive member 3 to form an electrostatic latent image having a potential higher than that of the surroundings on the photosensitive member 3, and a monochrome (black) toner on the electrostatic latent image. A developing device 8 that forms a toner image by attaching and developing, a transfer roll 9 that transfers the toner image by pressing the conveyed paper against the photoreceptor 3 on which the toner image is formed, By applying heat and pressure to the toner image, the fixing device 10 that fixes the toner image onto the sheet is brought into contact with the photoreceptor 3 and the toner remaining on the photoreceptor 3 after the toner image is transferred is cleaned. A cleaning blade 31 is provided. Yes. Here, the fixing device 10 corresponds to an example of a fixing device according to the present invention.

A developing device 8, a layer of the developer on the developing sleeve 81, developing scraping the developer carried on the developing sleeve 81 sleeve 81 which rotates in the arrow A ₁ direction in FIG carries a developer on the surface Two layer thickness adjusting plates 82a and 82b for adjusting the thickness, a container 83 in which the developer is stored, and two stirring portions 84a and 84b for stirring the developer in the container 83 are provided.

  Hereinafter, an image forming operation in the image forming apparatus 1000 will be described.

  The image forming apparatus 1000 is provided with a toner cartridge (not shown) in which black toner is stored, and toner is supplied to the developing device 8 by the toner cartridge. Further, the paper used for transferring the toner image is stored in the tray 1, and when the user gives an instruction to form an image, the paper is conveyed from the tray 1, and the toner image is transferred on the transfer roll 9. It is transported upward in the figure. In FIG. 1, the sheet conveyance path at this time is shown as a path indicated by an upward arrow, and after the toner image is fixed in the fixing device 10 through the sheet conveyance path, As indicated by the right arrow, it is discharged to the right.

  Next, the fixing device 10 shown in FIG. 1 will be described with reference to FIGS.

FIG. 2 is a schematic sectional view of the fixing device shown in FIG. Figure 3 is a view showing an appearance when viewed from an arrow C ₂ direction in FIG. 2.

  The fixing device 10 includes a heating member 11 that generates heat to fix the toner on the paper, and a pressure member 14 that applies pressure to the paper between the heating member 11 while being in contact with the heating member 11. ing.

  The heating member 11 includes a heater 12 that generates heat, and a cylindrical heating roll 110 that surrounds the heater 12. The heat generated by the heater 12 is transmitted to the heating roll 110 surrounding the heater 12, and this heat is used for fixing the toner on the paper. FIG. 2 shows a cross section of the cylindrical heating roll 110. The inside of the cylinder of the heating roll 110 is an aluminum cored bar 111, and an elastic layer 112 having a layer thickness of 1 mm made of silicon rubber, which is a kind of heat-resistant rubber, is overlaid on the cored bar 111. . In this way, the configuration in which the elastic layer 112 overlaps the core metal 111 is a cylindrical shape having a cylindrical core metal 111 and an inner diameter larger than the outer diameter of the core metal 111 in the cylindrical mold. These fluororesin tubes are installed so as to be concentric, and are formed by an injection molding method in which silicon rubber is injected into a gap between the core metal 111 and the fluororesin tube and molding is performed.

  The elastic layer 112 is an elastic layer formed by an injection molding method in this way, but an elastic layer formed on the cored bar 111 by a coating method can also be adopted as the elastic layer of the heating roll 110.

  On the outer surface of the elastic layer 112, a release layer having a layer thickness of 25 μm made of tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), which is a kind of fluororesin, is used to make it easier for the toner to be separated from the heating roll. 113 is provided.

  The pressing member 14 includes a support 142, a spring 143a, a belt guide 143 attached to the support 142, an elastic body 131 mounted on the support 142, a sheet-like member 132 covering the elastic body 131, and these supports. A body 142, a spring 143a, a belt guide 143, an elastic body 131, and a belt tubular body 141 surrounding the sheet-like member 132 are provided.

Here, the combination of the support 142, the spring 143a, the belt guide 143, the elastic body 131, and the sheet-like member 132 corresponds to an example of the pressing portion according to the present invention.
The belt tubular body 141 is a belt tubular body having a two-layer structure in which a release layer 141a of a perfluoroalkoxy fluororesin having a layer thickness of 30 μm and Φ30 is provided on a polyimide substrate 141b having a layer thickness of 80 μm. In this case, the support 142, the spring 143a, the belt guide 143, the elastic body 131, and the sheet-like member 132 are rotated. A lubricant is applied to the inner peripheral surface of the belt tubular body (the surface opposite to the surface in contact with the heating roll 110) so that the belt tubular body 141 rotates smoothly. This lubricant is a silicone oil containing a hindered amine-based antioxidant that has high heat resistance during long-term use and is hardly deteriorated by heat. The sheet-like member 132 is a member for improving the slidability between the belt tubular body and the elastic body 131, and also plays a role of holding the applied lubricant.

In the fixing device 10, the elastic body 131 covered with the sheet-like member 132 presses the belt tubular body 141 against the heating roll 110 to form a nip portion. At this time, the spring 143a plays a role of pressing the elastic body 131 toward the heating roll 110 with a pressure of 1.5 kg / cm ² by its elastic force and maintaining the pressure contact. Thus, the heat roll 110 while forming a nip portion is rotated in the direction indicated by the arrow B ₂ in FIG., In the pressure member side, the belt tubular body 141 which receives the rotational driving force of the heating roll 110, belt around the guide 143 in the direction indicated by arrow a ₂ in FIG driven to rotate. Paper 30 which has been conveyed to the fixing unit 10 from the direction indicated by arrow C ₂ in the figure passes through the nip portion between the heating roll 110 and the belt tubular body 141, in which it receives heat and pressure The unfixed toner image 301 on the paper 30 is fixed. After fusing, the sheet 30 is conveyed toward the fixing device 10 outside in the direction indicated by the arrow D ₂ in FIG.

  As the process of fixing the unfixed toner image 301 is repeated, the lubricant applied to the inner peripheral surface (surface on the elastic body 131 side) of the belt tubular body 141 may ooze out from the sheet-like member 132. is there. As the lubricant oozes out, the lubricant wraps around from the edge of the belt tubular body to the outer peripheral surface (surface on the pressure member side) of the belt tubular body, and between the belt tubular body 141 and the heating roll 110. In addition, a slip is formed on the recording medium, and a stain is formed by contacting the recording medium. Further, when the lubricant that has come to the outer peripheral surface side of the belt tubular body comes into contact with the elastic layer 112, the elastic layer 112 may swell, and as a result, the pressure distribution in the nip portion may be uneven. is there.

  In this fixing device 10, in order to avoid such a problem, the belt tubular body 141 is provided with a structure for preventing the lubricant from flowing from the edge of the belt tubular body 141 toward the outer peripheral surface side of the belt tubular body 141. ing. Below, this structure is demonstrated.

  FIG. 4 is a schematic diagram showing the structure of the inner peripheral surface of the belt tubular body 141.

In this figure, a part of the inner peripheral surface of the belt tubular body 141 is shown, and when the fixing process is performed, the belt tubular body 141 moves in the direction of the downward arrow in the figure. That is, the direction of the downward arrow corresponds to the direction of rotation indicated by the arrow A ₂ in Fig.

The inner peripheral surface of the belt tubular body 141, a center line A ₃ as a symmetrical axis, (in the figure symmetric) symmetrically toward both ends of the belt tubular body 141 and the structure of the protrusion is provided, in this figure, this projection is diagonal line 21a extending from the center line _{a 3} at both ends of the belt tubular body 141, are represented by 21b. Therefore, between these lines, a groove is formed that is lower than the portion represented by the diagonal lines 21a and 21b.

When the belt tubular body 141 moves in the direction of the downward arrow in the figure for fixing processing, the lubricant on the inner peripheral surface of the belt tubular body 141 is caused by the inertial force accompanying the movement of the belt tubular body 141, Although will receive a force directed upward, the structure of the above-mentioned ridges, rather than directly upward in the figure, it will be toward the center line a ₃ along the groove between the diagonal lines 21a, 21b .
As a result, lubricant on the inner peripheral surface while the fixing process is being performed, easily gather around the center line A ₃ of the belt tubular body 141, lubricant across the belt tubular body of the belt tubular body 141 It is suppressed that it goes around to the outer peripheral surface side.

However, this method is intended to utilize the inertial force accompanying the rotation of the belt tubular body 141, since the belt tubular body is not a force that attempts to pass lubricant toward the center line A ₃ is generated when not rotating, simple By simply providing the protrusion structure on the belt, it is not possible to prevent the lubricant from flowing from the edge of the belt tubular body to the outer peripheral surface side of the belt tubular body when rotation is stopped. Therefore, the belt tubular body 141 is further devised in order to prevent the lubricant from flowing from the edge of the belt tubular body to the outer peripheral surface side of the belt tubular body even when the rotation is stopped. Below, this device is demonstrated.

  FIG. 5 is a cross-sectional view of the left side portion of the circumferential surface of the belt tubular body shown in FIG. 4, and FIG. 6 is a cross-sectional view of the right side portion.

5 shows, the belt tubular body 141 shown in FIG. 4, the cross section of the ridge along the left side of the dotted line B ₃ are represented, in Figure 6, the cross section of the ridge along the right side of the dotted line C ₃ Is represented. As shown in these drawings, due to the presence of the protrusions, the cross section of the inner circumferential surface of the belt tubular body is repeatedly uneven, and the protrusions that are the cross sections of the protrusions have a triangular shape. The vertices of the triangles correspond to points on the diagonal lines 21a and 21b in FIG. 4, and the space between adjacent triangles corresponds to a groove through which the lubricant flows when the belt tubular body 141 rotates. The triangle shown in FIG. 5 has a shape inclined to the left end side of the belt tubular body 141, while the triangle shown in FIG. 6 has a shape inclined to the right end side of the belt tubular body 141. For this reason, in the triangle shown in FIG. 5, the inclination on the center line side of the belt tubular body 141 is gentler than the inclination on the left end side of the belt tubular body 141, and the triangle shown in FIG. The inclination on the center line side is gentler than the inclination on the right end side of the belt tubular body 141.

  Generally, when a lubricant adheres on the inner peripheral surface of the belt tubular body 141, the lubricant tends to spread along the inner peripheral surface of the belt tubular body 141 (that is, in the horizontal direction in FIGS. 5 and 6). appear. Therefore, in the triangular shape forming the convex portion of the concavo-convex shape of the inner peripheral surface of the belt tubular body 141, the inclination on the center line side is gentler than the inclination on the end side as shown in FIGS. By taking the shape, the lubricant with the lubricant adhering to the inner peripheral surface of the belt tubular body 141 is likely to spread in the direction of the center line side indicated by an arrow in the figure. As a result, the lubricant is prevented from spreading to both end sides of the belt tubular body 141.

Here, the concavo-convex shape of the cross section of the ridge formed of a series of triangles as shown in FIG. 5 is the triangle ABA when the perpendicular line AA ′ is lowered from the apex A of the triangle ABC to the base BC. It is determined by three parameters: the length L _{1 of the} “base BA” of “and the length L ₂ of the base CA ′ of the triangle ACA ′.

Also, a series of triangles, as shown in Figure 6, a series of triangles, as shown in FIG. 5, the central line A ₃ A symmetric, the length L ₁ of the 'base BA of the' triangular ABA 5 , and the series of triangles interchanging the length L ₂ of the 'bottom CA' of the triangle ACA.

Here, the cross-sectional shape of the inner peripheral surface of the belt tubular body 141 is, for example, the height h = 0.28 μm of the triangle and the length L ₁ of the bottom side of the triangle ABA ′ using the above three parameters = 1.0 μm. , The length L ₂ of the base of the triangle ACA ′ is 4.0 μm. In the cross-sectional shape of the inner belt tubular member 141 peripheral surface, triangular ACA 'length L ₂ of the base of the triangle ABA' has a 4 times the length L ₁ of the base of the central line side inclination, the end It is much gentler than the side slope.

  FIG. 7 is a diagram showing the uneven shape of the cross section of the inner peripheral surface of the belt tubular body formed by a series of triangles.

In this figure, the vertical axis a relief height of ridges, the direction along the belt tubular body peripheral surface (direction of the dotted line B ₃ in FIG. 4) as the horizontal axis, along the belt tubular body peripheral surface 2 The concavo-convex shape of the cross section of the inner peripheral surface of the belt tubular body 141 is represented by a curve over a length of 0.5 mm. Such a curve is obtained by measuring the inner surface of the belt tubular body 141 using a surface roughness meter. As can be seen from this figure, there are 28 convex portions in a length of 2.5 mm along the circumferential surface of the belt tubular body, and a triangle as shown in FIG. Indicates that there are 28 pieces in a length of 2.5 mm. The three parameters describing the triangular uneven shape described above are measured from such a curve.

  Next, by actually providing such a shape on the inner peripheral surface of the belt tubular body 141, the lubricant does not easily spread in the left direction in FIG. 5 (left end side of the tubular body), and the right direction in FIG. The fact that it tends to spread on the center line side of the body is explained using an experiment using lubricant oil droplets.

  FIG. 8 is a diagram showing how oil drops spread over time when lubricant drops are dropped on the left side portion of the belt tubular body shown in FIG. 4.

  Here, part (a) of FIG. 8 is a diagram showing how oil drops spread immediately after dropping, part (b) of FIG. 8 is a diagram showing how oil drops spread 10 seconds after dropping, FIG. Part (c) is a diagram showing how oil drops spread 5 minutes after dropping.

  As shown in part (a) of FIG. 8, immediately after the dropping, the lubricant oil droplet 600 spreads in a circular shape around the dropping point O. However, as shown in part (b) of FIG. 8, after 10 seconds, the oil droplet 600 tends to spread toward the center line side from the left end side of the belt tubular body 141. This tendency becomes clearer in the spread of the oil droplet 600 after 5 minutes of dripping shown in part (c) of FIG. From this, the cross-sectional shape of the inner peripheral surface of the tubular body 141 is a series of triangles in which the inclination on the center line side is gentler than the inclination on the left end side, as shown in FIG. It can be seen that the lubricant adhering to is likely to spread to the center line side rather than the left end side of the belt tubular body 141.

  In the embodiment described above, the cross-sectional shape of the inner peripheral surface of the belt tubular body 141 is a continuous triangle as shown in FIGS. 5 and 6, but the cross-sectional shape of the peripheral surface of the belt tubular body of the present invention is Instead of a series of triangles, a series of trapezoids may be used.

  Below, the belt tubular body in which the cross-sectional shape of the inner peripheral surface is a trapezoidal series will be described.

  This belt tubular body is different from the above-described belt tubular body 141 in that the cross-sectional shape of the inner peripheral surface is not a triangle but a trapezoidal series. It is the same as the tubular body 141. For this reason, a duplicate description is omitted here, and the following description will be made with a cross-sectional shape. As shown in FIG. 4, the belt tubular body is also provided with grooves extending obliquely from the central line toward both ends, as shown in FIG.

  9 is a cross-sectional view of the left portion of FIG. 4 on the inner peripheral surface of the belt tubular body whose cross-sectional shape is a trapezoidal shape, and FIG. 10 is a cross-sectional view of the right portion.

9 and 10, in the belt tubular body 141 ′ having a trapezoidal cross section on the inner peripheral surface, a cross section taken along the dotted line B ₃ on the left side of FIG. 4 and a dotted line C on the right side of FIG. 4. Sections along ₃ are shown respectively. As shown in these drawings, the convex portion of the cross section of the ridge has a trapezoidal shape, and the upper side of the trapezoid is connected along the ridge as diagonal lines 21a and 21b in FIG. The space between adjacent trapezoids, which are shown in parallel, corresponds to a groove through which the lubricant flows when the belt tubular body 141 ′ rotates. The trapezoid shown in FIG. 9 has a shape inclined to the left end side of the belt tubular body 141 ′, while the trapezoid shown in FIG. 10 has a shape inclined to the right end side of the belt tubular body 141 ′. For this reason, in the trapezoid shown in FIG. 9 and the trapezoid shown in FIG. 10, the inclination on the center line side of the belt tubular body 141 ′ is gentler than the inclination on the left end side and the right end side of the belt tubular body 141 ′, respectively. Yes. By taking such a shape, the lubricant adhering to the inner peripheral surface of the belt tubular body 141 ′ is likely to spread in the direction of the center line side indicated by an arrow in FIG. 9 and FIG. As a result, the lubricant is prevented from spreading to both end sides of the belt tubular body 141 ′.

  FIG. 11 is a diagram showing parameters for determining the cross-sectional shape in the cross-sectional shape composed of a series of trapezoids shown in FIG.

The cross-sectional shape of the belt tubular body 141 ′ having a trapezoidal series as shown in FIG. 9 is as follows: the trapezoidal height h, the upper side length L of the trapezoidal side, and the base BC from the upper left vertex A of the trapezoid ABCD The length L ₁ of the base BA ′ of the triangle ABA ′ when the perpendicular line AA ′ is lowered to the base line CD ′ of the triangle CDD ′ when the perpendicular line DD ′ is lowered from the upper right vertex D of the trapezoid ABCD to the base BC. Length L ₂ , and the five parameters of the distance d between adjacent trapezoids.

'The length _{L 1} of the base of the triangle CDD' triangle ABA by the ratio between the length _{L 2} of the base of,
The relative ratio of the left and right slopes of the trapezoid ABCD is determined, and as described above, if the slope of the right side of the trapezoid ABCD is more gradual than the slope of the left side of the trapezoid ABCD, the lubricant Although it tends to spread rightward, according to the experimental data described below,
L ₂ / L ₁ ≧ 3 (1)
It has been found that this tendency is particularly strong in the trapezoid shape satisfying the above condition, and the trapezoidal shape shown in FIG. 9 is a shape satisfying this condition.

In the above, the cross-sectional shape of the left side portion of the belt tubular body 141 ′ shown in FIG. 9 has been described. However, the cross-sectional shape of the right side portion of the belt tubular body 141 ′ shown in FIG. This is a shape in which L ₂ and L ₁ are interchanged, and the condition shown by the expression (1) is also satisfied for the cross-sectional shape of the right side portion. Therefore, in the right side portion of the belt tubular body 141 ′, the lubricant hardly spreads in the right direction in FIG. 10, but tends to spread in the left direction in FIG.

  Furthermore, in the present invention, as shown in FIGS. 12 and 13, two oil cleaning portions 60 may be provided near the ends of the belt tubular body 141 included in the pressure member 14 shown in FIG. 2 as necessary. Good.

13, in which the two oil cleaning section 60 provided in the fixing device shown in FIG. 12 is a diagram showing an external appearance when viewed from an arrow C ₂ direction in FIG. 12.

  As shown in this figure, the oil cleaning part 60 is located near both ends of the belt tubular body 141, so that the lubricant is absorbed even if the oil cleaning section 60 wraps around the belt tubular body from both ends of the belt tubular body. Can do.

  As shown in this figure, in the heating member 11, the cored bar 111 protrudes in both directions in the figure from the release layer 113 and the elastic layer 112 (not shown in FIG. 3) overlapping the release layer 113. It has a configuration. The lubricant that wraps around from the both ends of the belt tubular body to the outer peripheral surface side of the belt tubular body travels along the protruding portion of the core metal 111, and the end of the elastic layer 112 near the base of the protruding portion. There are also lubricants that approach In order to prevent such a lubricant from coming into contact with the elastic layer 112, it is a kind of heat-shrinkable fluororesin for covering the end of the elastic layer 112 near the base of the protruding portion of the core metal 111. A tube made of polytetrafluoroethylene (PTFE) may be provided.

  FIG. 14 is a cross-sectional view of the heating roll showing a state in which a tube made of heat-shrinkable fluororesin covers the end of the elastic layer.

  In this figure, among the projecting end portions of the core bar 111 shown in FIG. 13, the right side portion is shown enlarged. As shown in FIG. 14, the tube 50 having a thickness of 20 μm covers the end of the elastic layer 112 in the vicinity of the base of the protruding portion of the core metal 111, thereby preventing the end of the elastic layer 112 from being exposed to the outside. With such a configuration, the lubricant that wraps around the outer peripheral surface side of the belt tubular body 141 is prevented from coming into contact with the elastic layer 112. As a result, it is avoided that the elastic layer 112 swells and the pressure distribution in the nip portion is uneven. In this figure, only the right side portion is shown among the protruding end portions of the cored bar 111, but the left side portion is also provided with the same configuration and approaches the end of the elastic layer 112 from the left side. The incoming lubricant is also prevented from coming into contact with the elastic layer 112.

  The tube 50 shown in FIG. 14 covers the end of the elastic layer 112 and covers the core metal 111 near the end of the elastic layer 112 to some extent, thereby improving the binding property of the tube 50. If the tube covers the end and realizes a stable binding property, the function of preventing the contact between the lubricant and the elastic layer 112 is sufficiently exerted, so the portion covering the core metal 111 is shown in FIG. It is also possible to adopt a form that is shorter than the state.

  Further, the thickness of the tube is not necessarily 20 μm, and may be a tube having a thickness of 50 μm or less, and a tube having a thickness of 30 μm or less is particularly preferable. As the material of the tube to be used, in addition to the above PTFE, a fluororesin such as tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), or the like may be used. From the viewpoint of heat resistance of the fixing device, PTFE or PFA is preferable.

  In the following, by providing the cross-sectional shape described above on the inner peripheral surface of the belt tubular body 141 ′, the lubricant actually wraps around from the edge of the belt tubular body 141 ′ to the outer peripheral surface side of the belt tubular body 141 ′. It is verified by an experiment in which belt tubular bodies having different trapezoidal cross-sectional shapes are incorporated in a fixing device and operated.

  First, the manufacturing method of the belt tubular body used in this experiment will be described.

  FIG. 15 is a diagram illustrating a method for manufacturing a belt tubular body.

  In this manufacturing method, first, a polyimide substrate coating process is performed in which a polyimide base material is formed on the aluminum core material 211 to form a belt tubular substrate.

  Part (a) of FIG. 15 is a diagram showing a polyimide substrate coating process.

This polyimide substrate coating process, as shown in part (a) of FIG. 15, 360 mm aluminum core material 211, is rotated at a predetermined speed in the arrow A ₄ direction in the figure, the arrow B ₄ direction of FIG / An operation of discharging a polyimide base material (varnish) having a liquid viscosity of 130 Pa · s from the nozzle 213 of the discharge device (Mono pump) is performed while moving at a speed of min. And the base material 141b with a coating length of 500 mm is formed on the surface of the aluminum core material 211 by regulating the film thickness of the polyimide base material (varnish) with the spatula 212. This aluminum core material 211 is provided with a groove structure mold on its surface for providing a V-shaped groove structure as shown in FIG. 4 on the inner peripheral surface of the belt tubular body. In the coating process, a V-shaped groove structure as shown in FIG. 4 is formed on the base material 141b.

  In this embodiment, the base material 141b is formed through a polyimide base material coating step. Instead of such a polyimide base material coating step, dip coating (Dip-) is performed in which the aluminum core material 211 is immersed in a polyimide base material solution. It is also possible to form the base material 141b by a process using a coating method. In this case, in order to regulate the film thickness of the polyimide base material, a film thickness regulating ring can be used when the aluminum core material 211 is pulled up from the polyimide base material solution.

  After the polyimide base material coating step, a rotary drying step is performed.

  Part (b) of FIG. 15 is a diagram showing a rotary drying process.

In this step, the aluminum core material 211 substrate 141b is formed, as shown in part (b) of FIG. 15, while rotating at a rotational speed of approximately 20rpm in the arrow _{C 4} direction, temperature 120 ° C. The substrate 141b The work of drying for 70 minutes is performed.

  After the spin drying process, a surface layer dip coating process is performed.

  Part (c) of FIG. 15 is a diagram showing a surface layer dip coating process.

In this step, as shown in part (c) of FIG. 15, a polyperfluoroalkoxy fluoride plastic having a liquid viscosity of about 400 mPa · s is obtained by suspending an aluminum core member 211 on which a base material 141 b is formed by a shaft 214. (PFA) was immersed in a container containing 216 of coating 215, the task of pulling the arrow _{D 4} direction at a speed of approximately 200 mm / min is carried out. Through this surface layer dip coating process, a release layer 141a made of PFA is formed on the substrate 141b.

  In this embodiment, in order to form the release layer 141a, the surface layer dip coating process is performed. Instead of this surface layer dip coating process, the release layer is subjected to a process of spray-coating the substrate 141b with the PFA paint 215. 141a may be formed. Since the PFA paint has a low viscosity, the layer thickness is not regulated by a film thickness regulating ring or the like in any of the spray coating process or the surface layer dip coating process employed in this embodiment. May be.

  After the surface layer dip coating process, a substrate / release layer firing process is performed.

  Part (d) of FIG. 15 is a diagram showing a base material / release layer firing step.

  In this step, the base material 141b and the release layer 141a are baked at a temperature of 380 ° C. for about 1 hour.

  Finally, a removal process is performed.

  Part (e) of FIG. 15 is a diagram showing the removal process.

  In this step, after the base material 141b and the release layer 141a are fired, the aluminum core material 211 is removed, and the end portions of the fired base material 141b and the release layer 141a are cut to adjust the shape. . And the belt tubular body which consists of the base material 141b and the mold release layer 141a is completed by this operation | work.

  The above is description of the manufacturing method of a belt tubular body.

  In such a manufacturing method, five belt tubular shapes having different trapezoidal shapes shown in FIG. 9 and FIG. 10 are used by using five types of aluminum cores having a groove structure having different cross-sectional shapes. Prepare your body.

These five belt tubular bodies are the belt tubular bodies of Examples 1 to 5. The trapezoidal shapes of the first to fifth embodiments can be represented by the parameters shown in FIG. 11. The height h of the trapezoid, the length L of the upper side of the trapezoid, the distance d between adjacent trapezoids, and the base of the triangle ABA ′ the length L ₁ is of a all common values,
h = 2.8 μm, L = 5.0 μm, d = 5.0 μm, L ₁ = 16.9 μm
It is. The length _{L 2} of the base of the triangle CDD ', all different in Examples 1 to 5.

  FIG. 16 is a diagram illustrating numerical values of parameters representing trapezoidal shapes in the first to fifth embodiments.

In this figure, the above-described, the value of the common parameter, and the length L ₂ of the base of the triangle CDD 'are shown for each example. These five parameters h, L, d, L ₁ and L ₂ are independent parameters that determine the trapezoidal shape. In this figure, in addition to these independent parameters, the ratio of the base lengths of the two triangles CDD ′ and triangle ABA ′ in FIG. 11 (L ₂ / L ₁ ), the base BC of the trapezoid ABCD and the left hypotenuse The angle θ ₁ formed by AB and the angle θ ₂ formed by the base BC of the trapezoid ABCD and the right oblique side CD are also shown. These two angles θ ₁ , θ ₂ are respectively θ ₁ = tan ⁻¹ (h / L ₁ ) and θ ₂ = tan ⁻¹ (h / L ₂ ) according to the above independent parameters.
It is expressed.

As can be seen from this figure, the length L ₂ of the base of the triangle CDD 'is, Example 5, Example 4, Example 1, Example 2, with the possible becomes larger in the order of Example 3, the two The ratio of the base of the triangle (L ₂ / L ₁ ) also increases in this order. Here, in Example 5, L ₂ / L ₁ = 2.1, and in Example 4, L ₂ / L ₁ = 3.0. It turns out that Example 2 and Example 3 are Examples which satisfy | fill the conditions of Formula (1).

Further, with respect to the angle theta ₁ formed by the base BC and the left oblique side AB of the trapezoid ABCD in the range of 9.4 °, the five embodiments described above, formed by the hypotenuse CD base BC and the right side of the trapezoid ABCD The angles θ ₂ are both smaller than 9.4 °, and in these examples, the hypotenuse of the two hypotenuses of the trapezoid facing the center line side has a gentler inclination. Represents that.

Moreover, as a comparative example with respect to these Examples 1 to 5, the height h of the trapezoid, the length L of the upper side of the trapezoid, and the distance d between adjacent trapezoids are the same values as in Examples 1 to 5. Yes, for the length L ₁ of the base of the triangle ABA ′ and the length L ₂ of the base of the triangle CDD ′,
L ₁ = L ₂ = 72.9 μm
A belt tubular body is prepared. The parameters of this belt tubular body are shown in FIG. The belt tubular body of Comparative Example 1 is also manufactured by the same manufacturing method as in Examples 1 to 5. In Comparative Example 1, the value of the ratio (L ₂ / L ₁ ) of the bases of the two triangles is L ₂ / L ₁ = 1, which is a small value compared to Examples 1 to 5. The cross-sectional shape of the circumferential surface of the belt tubular body in Example 1 is a cross-sectional shape that is not different between the end side direction of the belt tubular body and the central line side direction in the direction in which the lubricant is likely to spread.

  As a comparative example different from the comparative example 1, a belt tubular body having an inner peripheral surface with an arithmetic average roughness (Ra) of about Ra = 0.4 μ is prepared. The manufacturing method of this belt tubular body is the same as the manufacturing method of Example 1- Example 5 except using the aluminum core material which performed smooth finishing of Ra = 0.5 micrometer. This comparative example is Comparative Example 2. The belt tubular body of Comparative Example 2 is a belt tubular body having a substantially smooth inner circumferential surface, with the unevenness of the cross section of the inner circumferential surface being smaller than those of Examples 1 to 5 and Comparative Example 1.

  Here, various amounts characterizing the belt tubular bodies of Examples 1 to 5 and Comparative Examples 1 and 2 described above are obtained by measuring the axial roughness of the inner surface of the belt tubular body with a surface roughness meter. This is the amount obtained from the cross-sectional curve when measured at a measurement length of 2.5 mm. Further, the belt tubular body inner surface also has irregularities such as the undulation of the belt tubular body itself. In general, the repetition cycle of such irregularities is larger than the period of the irregularities in the cross section due to the presence of the protrusions. Therefore, in this surface roughness meter, in order to cut the irregularities with such a large period, the cut-off value is set to 0.25 mm, the repetition of irregularities with a period of 0.25 mm or more is cut, and the presence of the protrusions The unevenness of the cross section is measured.

  After manufacturing the belt tubular bodies of Examples 1 to 5 and Comparative Examples 1 and 2, each belt tubular body is the same as the fixing device 10 shown in FIG. Attach to a fuser with components. Then, the pressure member shape is adjusted to set the width of the nip portion to 10 mm, and the spring 143a is adjusted at room temperature to set the load applied to the nip portion to 34 kg.

  The fixing is performed by attaching the belt tubular bodies of Examples 1 to 5 and Comparative Examples 1 and 2 under the conditions that the surface temperature of the heating roll 110 is 185 ° C. and the process speed is 195 mm / s. A 30-minute cycle operation in which the vessel is continuously run for 30 minutes and then stopped for 30 minutes, in which continuous running and running stop are alternately repeated, is performed continuously for 150 hours.

  In this 30 hour cycle operation for 150 hours, the sliding torque (H / R shaft torque) during operation of the fixing device and the lubricant from the vicinity of both ends of the circumferential surface of the belt tubular body are detected every 50 hours. Investigate the degree of penetration into the surface.

  The sliding torque is an amount obtained by evaluating the torque of the heating roll 110 through a gear interlocked with the rotation of the heating roll 110, and represents the magnitude of torque necessary to rotate the heating roll 110. If the belt tubular body has a sufficient amount of lubricant and the belt tubular body moves smoothly when the fixing device is in operation, the torque required to rotate the heating roll 110 is not so large. When the lubricant oozes out from the inner peripheral surface of the belt tubular body to the outer peripheral surface and the lubricant on the inner peripheral surface of the belt tubular body is insufficient, the friction force received by the belt tubular body increases, and accordingly, the heating roll 110 is rotated. The amount of torque required is also increased. Therefore, from the measurement of the sliding torque, it is possible to estimate to some extent how the lubricant exudes from the inner peripheral surface of the belt tubular body.

  In investigating the degree of penetration of the lubricant from the outer peripheral surface of the belt tubular body into the outer peripheral surface, the degree of penetration is determined by determining the distance that the lubricant has entered on the outer peripheral surface side of the belt tubular body from the end of the belt tubular body. Measure with a scale and evaluate the results divided into the following categories.

○: Within 2 mm from the end of the belt tubular body Δ: From 2 mm to within 5 mm from the end of the belt tubular body ×: From 5 mm to within 10 mm from the end of the belt tubular body XX: From 10 mm to within 20 mm from the end of the belt tubular body XX : 20 mm or more from the end of the belt tubular body And, in the fixing device after the end of the 30-minute cycle operation for 150 hours, the surface temperature of the heating roll 110 is set at 185 ° C., and the basis weight of 64 gsm made by Fuji Xerox 100 sheets of paper are output continuously at an output speed (P / S) of 195 mm / S using the paper, and the number of sheets where the stain by the lubricant has occurred in the output result is investigated.

  The experiment described above is Experiment 1.

  FIG. 17 is a diagram showing the measurement result of the sliding torque in Experiment 1. FIG.

  As shown in this figure, for Examples 1 to 5 and Comparative Example 1, the sliding torque is almost within the range of 0.45 N · m to 0.5 N · m. On the other hand, Comparative Example 2 is around 0.6 N · m, which is an extremely large value as compared with Examples 1 to 5 and Comparative Example 1. This indicates that the belt tubular body of Comparative Example 2 has a structure for preventing the lubricant from exuding from the inner peripheral surface as compared with the belt tubular bodies of Examples 1 to 5 and Comparative Example 1. It is estimated that the lubricant is insufficient on the inner peripheral surface of the belt tubular body of Comparative Example 2.

  FIG. 18 is a diagram showing a measurement result of the degree of penetration of the lubricant into the outer peripheral surface of the belt tubular body and an examination result of the number of stains generated by the lubricant in Experiment 1.

As shown in this figure, the condition of the formula (1) is satisfied in both results of the degree of penetration of the lubricant into the outer peripheral surface side of the belt tubular body every 50 hours and the number of stains caused by the lubricant. Example 1, Example 2, Example 3 and Example 4 obtained good results that the degree of penetration of the lubricant was low and no stain was generated by the lubricant. Among Example 5, Comparative Example 1 and Comparative Example 2, it occupies the top four.

In Example 4, L ₂ / L ₁ = 3.0, and the values of (L ₂ / L ₁ ) in Example 1, Example 2, and Example 3 are both (L ₂ / L ₁ ). ₂ / L ₁ ), and therefore, if the value of (L ₂ / L ₁ ) is 3 or more, the lubricant stains from the inner peripheral surface of the belt tubular body to the outer peripheral surface. It is assumed that the release is sufficiently suppressed.

Here, Example _{3, (L} 2 / L ₁₎ a value of 11.9, Example 1 of _(L 2 / L ₁₎ of the values 4.3, and Example 2 _{(L 2} / compared to _{L 1)} of the values _{8.6, (L 2 / L 1} ) values despite larger, the result of Figure 18, the outer peripheral surface of the belt tubular body 30 minutes after cycle operation 150 hours The degree of penetration of the lubricant increased, and the evaluation was slightly lower than in Example 1 and Example 2. This is because as the value of L ₂ increases, the slope on the center line side (the slope on the L ₂ side of the trapezoid) becomes increasingly gentle and the unevenness of the cross section of the inner peripheral surface of the belt tubular body approaches flat. In the concavo-convex shape having a value of (L ₂ / L ₁ ) of 11.9 or more, the function as a groove for allowing the lubricant to flow toward the center line side when the belt tubular body rotates is reflected. I can see that it is not so expensive.

In Example 5, the penetration of the lubricant into the outer peripheral surface side of the belt tubular body was observed after 30 hours of cycle operation for 100 hours, which is somewhat worse than Examples 1 to 4, but 30 Even after 150 minutes of minute cycle operation, the lubricant does not invade further, and has reached a level that is almost acceptable. In Example 5, the value of (L ₂ / L ₁ ) was 3 or less, which was slightly smaller than those in Examples 1 to 4, compared with Examples 1 to 4. For this reason, it is thought that the cause is that the function of moving the lubricant to the center line side is not higher than in the first to fourth embodiments.

  On the other hand, in Comparative Example 1, the degree of intrusion of the lubricant increases after 100 hours of 30-minute cycle operation and 150 hours of 30-minute cycle operation, and is due to the intrusion of lubricant as compared with Examples 1 to 5. The result is a concern. The belt tubular body of Comparative Example 1 is a belt tubular body that has no difference between the end side direction of the belt tubular body and the central line side direction from the viewpoint of the direction in which the lubricant easily spreads, and has the structure shown in FIG. The belt tubular body in which the lubricant is prevented from entering the outer peripheral surface of the belt tubular body only when the belt tubular body is rotated. The results of Comparative Example 1 above reflect that when the belt tubular body does not rotate, there is no effect of suppressing the penetration of the lubricant into the outer peripheral surface side of the belt tubular body.

  Further, unlike Examples 1 to 5 and Comparative Example 1, Comparative Example 2 which does not have a V-shaped groove structure as shown in FIG. Are worse than those of Examples 1 to 5 and Comparative Example 1, and a stain due to the lubricant appears on 15 sheets of output paper. From this, it can be seen that simply imparting roughness to the inner peripheral surface of the belt tubular body has no effect of suppressing the penetration of the lubricant into the outer peripheral surface of the belt tubular body.

  The above is the explanation of Experiment 1 and the results.

  Next, the belt tubular bodies of Examples 1 to 5 and Comparative Examples 1 and 2 are manufactured again, and each element of the pressure member 14 other than the belt tubular body and the heating member 11 are replaced with new ones. The experiment similar to Experiment 1 is performed by setting the surface temperature of the heating roll 110 to 200 ° C., which is a higher temperature than Experiment 1. This is Experiment 2, which is an experiment in which the fixing device is run under conditions where the output conditions are severe (the load is large) compared to Experiment 1. In this experiment 2, when the sliding torque is measured when the fixing device is operated, the control temperature is reset to 185 ° C. as in experiment 1, and the measurement is performed.

  FIG. 19 is a diagram showing the measurement result of the sliding torque in Experiment 2. FIG.

  As shown in this figure, in Examples 1 to 4, the sliding torque is substantially within the range of 0.45 N · m to 0.5 N · m, whereas Example 5 Then, the sliding torque is slightly larger than those of the first to fourth embodiments, and the comparative example 1 has a larger sliding torque than the first to fourth embodiments. The tendency that the sliding torque increases with time is increasing. For Comparative Example 2, as in FIG. 17, the largest sliding torque is found in Examples 1 to 5, Comparative Example 1 and Comparative Example 2. These results reflect that since the surface temperature of the heating roll 110 has increased, the fluidity of the lubricant has increased, making it easier for the lubricant to enter the outer peripheral surface from the inner peripheral surface of the belt tubular body, Even if it has a structure that prevents the seepage of the lubricant from the inner peripheral surface as in Example 5 and Comparative Example 1, if the effect of suppressing the seepage is small, lubrication from the inner peripheral surface of the belt tubular body to the outer peripheral surface is possible. This means that the intrusion of the agent cannot be stopped.

  FIG. 20 is a diagram illustrating a measurement result of the degree of penetration of the lubricant into the outer peripheral surface of the belt tubular body and an examination result of the number of stains generated by the lubricant in Experiment 2.

  Reflecting the fact that the output conditions are stricter than Experiment 1 (the load is large), the degree of penetration of the lubricant is advanced at an earlier stage than Experiment 1 as a whole. In particular, in Comparative Example 1 and Comparative Example 2, the number of output sheets in which a stain due to the lubricant appears is 15 and 25, respectively, which is worse than Experiment 1.

In the relative comparison between Example 1 to Example 5, Comparative Example 1 and Comparative Example 2, as in Experiment 1, Examples 1 to 4 satisfying the condition of formula (1) The degree of intrusion is relatively low and the occurrence of stains due to the lubricant is small, and these occupy the top four in Examples 1 to 5 and Comparative Examples 1 and 2. Also from this result, it is presumed that the belt tubular body having a value of (L ₂ / L ₁ ) of 3 or more has a great effect of suppressing the seepage of the lubricant from the inner circumferential surface of the belt tubular body to the outer circumferential surface.

  In Example 5, there is a tendency that the degree of penetration of the lubricant is advanced as compared with Examples 1 to 4, but the degree of penetration of the lubricant is still higher than those of Comparative Example 1 and Comparative Example 2. Slow, there are few stains by a lubricant, and the effect by having the cross-sectional shape of FIG. 9 and FIG. 10 has appeared.

Summarizing the results of FIGS. 17 to 20 described above, in the belt tubular body 141 ′ in which the value of (L ₂ / L ₁ ) is larger than ₁ , as in Examples 1 to 5, the lubricant is belt tubular. body 141 'edge there is the effect of suppressing flowing around the outer peripheral surface side from, in particular, belt tubular has a value of the _(L 2 _/ L ₁₎ as in examples 1 to 4 is 3 or more It can be concluded that the body 141 ′ has a large inhibitory effect.

  Here, verification was performed based on experimental data in the case where the uneven shape of the cross section of the inner surface of the belt tubular body is a trapezoidal series, but the uneven shape of the cross section of the inner surface of the belt tubular body is a continuous series of triangles. The same can be concluded for the case.

  In the embodiment described above, the protrusions on the circumferential surface of the belt tubular body extend symmetrically with respect to the central line from the central line toward both ends of the belt tubular body. However, it may extend asymmetrically with respect to the central line.

  The image forming apparatus according to the embodiment described above is a monochrome double-sided output printer, but the present invention may be applied to a color printer.

  Further, in the embodiment described above, the core metal 111 made of aluminum is used in the heating roll 110. However, the material of the core metal used in the present invention only needs to have excellent mechanical strength and good heat conductivity. In addition to aluminum, for example, metals such as SUS, iron, copper, alloys, ceramics, FRM, and the like can be given.

  In the embodiment described above, polydimethyl silicone rubber is used as the material of the elastic layer 112 in the heating roll 110. However, in addition to this, other known heat-resistant rubbers such as silicone rubber and fluororubber are appropriately used. You can choose. Among heat resistant rubbers, silicon rubber is preferable from the viewpoint of low surface tension and excellent elasticity, and examples thereof include RTV silicon rubber and HTV silicon rubber. More specifically, polydimethyl silicone rubber (MQ), methyl vinyl silicone rubber (VMQ), methyl phenyl silicone rubber (PMQ), fluoro silicone rubber (FVMQ) and the like can be mentioned. The thickness of the elastic layer is usually 3 mm or less, preferably 0.5 to 1.5 mm. As a method for forming the elastic layer on the surface of the core, a known method such as an injection molding method or a coating method can be employed.

  In the embodiment described above, PTFE (polytetrafluoroethylene) is adopted as the material of the release layer 113 provided in the heating roll 110. In addition to this, an appropriate release property for the toner image is used. As the material, for example, a fluororesin such as PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer) or FEP (tetrafluoroethylene-hexafluoropropylene copolymer) is used. . Moreover, as thickness of the said mold release layer, it may be normally 10-100 micrometers, Preferably it is 20-30 micrometers.

  In this embodiment, hindered amine oil is used as the lubricant. However, the present invention is not limited to hindered amine oil, but also amino-modified silicone oil, dimethyl silicone oil, mercapto-modified silicone oil, and amino-modified silicone containing an antioxidant. The hindered amine oil etc. which are oil can be used.

  In the embodiment described above, the belt tubular body rotates around the belt guide 143 without being stretched around a roll or the like. However, in the present invention, the belt tubular body is stretched around a roll or the like. It may be one that rotates around the belt guide. In this embodiment, a two-layer structure in which a release layer of perfluoroalkoxy fluororesin is superimposed on a polyimide base material is used as the structure of the belt tubular body. However, the present invention has a single-layer structure. May be. Further, as a material for the base material of the belt tubular body, polyamide, polyamideimide, polybenzimidazole, or the like may be used in addition to the polyimide. As a material for the release layer 141a of the belt tubular body, in addition to the above perfluoroalkoxy fluororesin, for example, polytetrafluoroethylene (PTFE), tetrafluoroethylene / hexafluoropropylene copolymer (FEP), polyethylene -Fluororesin such as tetrafluoroethylene (ETFE), polyvinylidene fluoride (PVDF), polychloroethylene trifluoride (PCTFE), and vinyl fluoride (PVF).

1 is an overall configuration diagram showing an embodiment of an image forming apparatus of the present invention. It is a schematic sectional drawing of the fixing device shown in FIG. The fixing device shown in FIG. 2 is an external view as viewed from arrow C ₂ direction in FIG. 2. 4 is a schematic diagram showing the structure of the inner peripheral surface of a belt tubular body 141. FIG. It is sectional drawing of the left side part of the belt tubular body internal peripheral surface shown in FIG. It is sectional drawing of the right side part of the belt tubular body internal peripheral surface shown in FIG. It is a figure showing the uneven | corrugated shape of the cross section of the belt tubular body internal peripheral surface formed by the continuous triangle. FIG. 5 is a diagram illustrating how oil droplets spread with time when oil droplets of a lubricant are dropped on the left side portion of the belt tubular body illustrated in FIG. 4. FIG. 5 is a cross-sectional view of the left portion of FIG. 4 on the inner peripheral surface of a belt tubular body having a trapezoidal cross-sectional shape. FIG. 5 is a cross-sectional view of the right side portion of FIG. 4 on the inner peripheral surface of a belt tubular body having a trapezoidal cross-sectional shape. FIG. 10 is a diagram showing parameters for determining the cross-sectional shape in the cross-sectional shape including a series of trapezoids shown in FIG. 9. FIG. 3 is a schematic sectional view in which an oil cleaning unit 60 is provided in the fixing device shown in FIG. 2. The fixing device shown in FIG. 12 is an external view as viewed from arrow C ₂ direction in FIG. 12. It is sectional drawing of a heating roll showing a mode that the tube comprised with the heat-shrinkable fluororesin had covered the end of the elastic layer. It is a figure which shows the manufacturing method of the belt tubular body used in the experiment of this embodiment. It is a figure showing the numerical value of the parameter showing the shape of a trapezoid in Example 1- Example 5. FIG. In Experiment 1, it is a figure showing the measurement result of sliding torque. In Experiment 1, it is a figure showing the measurement result of the penetration | invasion of the lubricant to the outer peripheral surface of a belt tubular body, and the investigation result of the number of the stain | pollution | occurrence | production numbers by a lubricant. In Experiment 2, it is a figure showing the measurement result of sliding torque. In Experiment 2, it is a figure showing the measurement result of the penetration | invasion of the lubricant to the outer peripheral surface of a belt tubular body, and the investigation result of the number of stains generated by the lubricant.

Explanation of symbols

1000 Image forming apparatus 1 Tray 2 Charger 3 Photoconductor 31 Cleaning blade 7 Exposure unit 8 Development unit 81 Development sleeve 82a, 82b Layer thickness adjusting plate 83 Container 84a, 84b Stirring unit 9 Transfer roll 10 Fixing unit 11 Heating member 12 Heating heater DESCRIPTION OF SYMBOLS 110 Heat roll 111 Core metal 112 Elastic layer 113 Release layer 131 Elastic body 132 Sheet-like member 141, 141 'Belt tubular body 141a Release layer 141b Base material 142 Support body 143 Belt guide 143a Spring 14 Pressurizing member 21a, 21b Diagonal Line 30 Paper 301 Unfixed toner image 50 Tube 60 Oil cleaning unit 61 Core shaft 62 Felt 600 Oil droplet 211 Aluminum core material 212 Spatula 213 Nozzle 214 Shaft 215 PFA paint 216 Container

Claims (3)

A belt body having the shape of a tube;
In the direction intersecting with the extending direction, which extends in a direction inclined with respect to the circumferential direction of the inner peripheral surface, provided on the inner peripheral surface of the belt main body and arranged in a plurality on the inner peripheral surface. Both hems are widened, and the first hem of the two hems facing the edge of the belt body is provided with a ridge that is steeper than the second hem facing the inside of the belt body. A belt tubular body characterized by the above. In a fixing device for fixing an unfixed toner image,
A rotating member that rotates;
A belt tubular body that circumscribes the rotating member and rotates in a driven manner, and a belt main body having a tube shape, and an inner peripheral surface of the belt main body, the first being along an edge of the belt main body on one end side of the pipe. A plurality of lines are arranged in one area. The hem extends on the inner peripheral surface in a direction inclined with respect to the circumferential direction of the inner peripheral surface, and both hems extend in a direction intersecting the extending direction. A belt tubular body having a protrusion whose first hem facing the edge of the belt main body is a steeper slope than the second hem facing the inner side of the belt main body,
By pressing the belt tubular body against the rotating member from the inside of the belt tubular body, a nip portion where the rotating member and the belt tubular body are in contact is formed, and the nip portion is formed on the unfixed toner image. A fixing device comprising: a pressing unit that fixes the unfixed toner image onto the recording medium when the carried recording medium passes through. In an image forming apparatus for forming an image composed of a fixed toner image on a recording medium,
A toner image forming unit for forming an unfixed toner image on the recording medium;
A rotating member that rotates;
A belt tubular body that circumscribes the rotating member and rotates in a driven manner, and a belt main body having a tube shape, and an inner peripheral surface of the belt main body, the first being along an edge of the belt main body on one end side of the pipe. A plurality of lines are arranged in one area. The hem extends on the inner peripheral surface in a direction inclined with respect to the circumferential direction of the inner peripheral surface, and both hems extend in a direction intersecting the extending direction. A belt tubular body having a protrusion whose first hem facing the edge of the belt main body is a steeper slope than the second hem facing the inner side of the belt main body,
By pressing the belt tubular body against the rotating member from the inside of the belt tubular body, a nip portion where the rotating member and the belt tubular body are in contact is formed, and the nip portion is formed by the toner image forming portion. An image forming apparatus comprising: a pressing unit that fixes a non-fixed toner image on the recording medium when a recording medium carrying the formed non-fixed toner image passes through the recording medium.

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