JP7147315B2 - Fixing device and image forming device - Google Patents

Description

The present invention relates to a fixing device and an image forming apparatus having the fixing device.

2. Description of the Related Art In general, as a fixing device used in an image forming apparatus, one having an endless cylindrical fixing member (fixing belt) and a pressure member is known. In such a fixing device, a nip portion is formed by the fixing member and the pressure member, and the toner is fixed onto the recording paper by applying pressure and heat to the nip portion.

As such a fixing device, there has been proposed a device in which a lubricant is applied to the inner surface of the fixing belt so that the fixing belt can easily slide against a member disposed inside (for example, see Patent Document 2). 1). In the fixing device disclosed in Patent Document 1, grooves are formed on the outer peripheral surface of an absorbing member supporting member arranged inside the fixing belt, and lubricant is fixed by arranging the lubricant absorbing member in the grooves. It suppresses leakage from the end of the belt.

However, in the fixing device described in Japanese Patent Application Laid-Open No. 2002-200011, when the lubricant flows toward the widthwise end of the fixing belt, even if the leakage can be suppressed, the lubricant is absorbed by the lubricant absorbing member. Therefore, the total amount of lubricant adhering to the fixing belt may decrease. At this time, the lubricant is likely to run short particularly in the central portion in the width direction of the fixing belt. Insufficient lubricant increases the sliding resistance between the fixing belt and the inner members, making it difficult for the fixing belt to rotate smoothly.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a fixing device and an image forming apparatus capable of maintaining a low sliding resistance when a fixing member rotates.

The invention according to claim 1 comprises a pressing member, an endless cylindrical fixing member provided opposite to the pressing member, a heat source for heating the fixing member, and the pressing member sandwiching the fixing member. a nip forming means arranged on the opposite side of a member to form a nip portion, wherein the nip forming means contacts the inner surface of the fixing member on the nip forming means side. and a holding means for holding the woven fabric member, wherein at least the warp yarns on both sides in the width direction of the woven fabric member are aligned in the rotation direction of the fixing member. The woven fabric member is held so as to be inclined from the end portion in the width direction toward the center portion as it goes from the upstream side to the downstream side in the The fixing device is characterized in that it holds a fabric member, and the restricting force on the upstream side is stronger than the restricting force on the downstream side .
According to a second aspect of the invention, there is provided a pressing member, an endless cylindrical fixing member provided opposite to the pressing member, a heat source for heating the fixing member, and the pressing member sandwiching the fixing member. a nip forming means arranged on the opposite side of a member to form a nip portion, wherein the nip forming means contacts the inner surface of the fixing member on the nip forming means side. and a holding means for holding the woven fabric member, wherein at least the warp yarns on both sides in the width direction of the woven fabric member are aligned in the rotation direction of the fixing member. The fabric member is held so as to incline from the end portions in the width direction toward the center portion in the direction from the upstream side to the downstream side of the fabric member, and the fabric member has a predetermined first shape along the width direction. The holding means has a plurality of holding portions arranged in a predetermined second shape along the width direction, and the first shape and the second shape is different, the wefts of the fabric member are convexly curved toward the upstream side, and the warps are inclined .

According to the fixing device of the present invention, the fabric member is held by the holding means, so that the warp threads are directed from the ends in the width direction to the central portion as they go from the upstream side to the downstream side in the rotation direction of the fixing member. incline. Since the fabric member contacts the inner surface of the fixing member, the lubricant adhering to this inner surface moves along the warp threads. Therefore, the lubricant adhering to the inner surface of the fixing member is guided toward the central portion in the width direction when the fixing member rotates. As a result, the lubricant is prevented from flowing toward the widthwise end portion of the fixing member, and leakage of the lubricant is suppressed. At this time, since it is not necessary to absorb the lubricant in order to suppress leakage of the lubricant, the total amount of the lubricant on the inner surface of the fixing member is unlikely to decrease. Therefore, shortage of the lubricant is unlikely to occur on the inner surface of the fixing member, and sliding resistance when the fixing member rotates can be kept low.

1 is a cross-sectional view showing a fixing device according to a first embodiment of the invention; FIG. 2 is a cross-sectional view showing an outline of an image forming apparatus provided with the fixing device; FIG. 4 is a plan view showing a main part of nip forming means of the fixing device; FIG. 4 is a plan view schematically showing the flow of lubricant in the fixing member of the fixing device; FIG. 3A and 3B are cross-sectional views schematically showing the operation of the fixing device; FIG. FIG. 9 is a plan view showing a fabric member in a fixing device according to a second embodiment of the invention; 3 is a perspective view showing holding means in the fixing device; FIG. It is a top view which shows the said holding means. 4 is a plan view schematically showing the flow of lubricant in the fixing member of the fixing device; FIG.

Hereinafter, each embodiment of the present invention will be described based on the drawings. In addition, in the second embodiment, the same reference numerals as in the first embodiment are given to the same constituent members and the constituent members having the same functions as the constituent members explained in the first embodiment, and the explanation thereof is omitted.

[First embodiment]
The fixing device 1 of the present embodiment is provided in an image forming apparatus (see FIG. 2) 100, and as shown in FIG. forming means 5;

[Fixing device]
The fixing member 2 is, for example, a metal belt such as nickel or SUS, or a belt made of a resin material such as polyimide in an endless cylindrical shape, or may be a film. The surface layer of the belt has a release layer such as a PFA or PTFE layer, and has release properties so that toner does not adhere. An elastic layer formed of a silicone rubber layer or the like may be provided between the base material of the belt and the PFA or PTFE layer. In the absence of the silicone rubber layer, the heat capacity is reduced and the fixability is improved. Gloss unevenness (yuzu skin image) tends to remain. In order to improve this, it is preferable to provide the silicone rubber layer with a thickness of 100 μm or more. Deformation of the silicone rubber layer absorbs minute irregularities and improves the yuzu skin image.

A support member (stay) 6 for supporting the nip forming means 5 is provided inside the fixing member 2 to prevent bending of the nip forming means 5 which receives pressure from the pressure member 4, thereby forming a uniform nip in the axial direction. Width can be obtained.

Further, the fixing device 1 is provided with a reflecting member 7 between the heat source 3 and the support member 6 to suppress wasteful energy consumption due to the support member 6 being heated by radiant heat from the heat source 3 or the like. there is Here, instead of providing the reflecting member 7, the surface of the supporting member 6 may be thermally insulated or mirror-finished to obtain the same effect.

The heating source 3 may be the illustrated halogen heater, but may also be an IH, a resistance heating element, a carbon heater, or the like. The heat source 3 directly heats the fixing member 2 from the inner peripheral side. If the heat source 3 is a halogen heater, the fixing device 1 may have a light blocking plate. The light blocking plate blocks the light emitted by the halogen heater so that the fixing member 2 is heated within a range corresponding to the size of the recording paper. The light-shielding plate has light-passing portions corresponding to various recording paper sizes, and for example, by rotating, an appropriate light-passing portion is positioned between the heat source 3 and the fixing member 2. .

The pressure member 4 is provided with an elastic rubber layer 4B on the outer side of a metal core 4A, and a release layer (PFA or PTFE layer) (not shown) is provided on the surface of the elastic rubber layer 4B in order to obtain release properties. ing. The pressing member 4 rotates when a driving force is transmitted through gears from a driving source such as a motor provided in the image forming apparatus 100 shown in FIG. The pressure member 4 is pressed against the fixing member 2 by a spring or the like, and has a predetermined nip width due to the elastic rubber layer 4B being crushed and deformed.

The pressure roller may be a hollow roller and may have a heating source such as a halogen heater. The elastic rubber layer may be made of solid rubber, but if there is no heater inside the pressure roller, sponge rubber may be used. It is more preferable to use sponge rubber, since the heat insulation is improved and the heat of the fixing sleeve is less likely to be lost.

The nip forming means 5 is arranged inside the fixing member 2 , that is, arranged on the opposite side of the pressure member 4 with the fixing member 2 interposed therebetween. Thereby, a nip portion N is formed by the fixing member 2 and the pressure member 4 which are arranged to face each other. The recording paper having the toner image transferred thereon passes through the nip portion N and is heated and pressurized to fix the toner image on the recording paper.

Although the shape of the nip portion N is flat in FIG. 1, it may be concave or other shapes. (When the shape of the nip portion is concave, the discharge direction of the leading edge of the recording paper is closer to the pressure roller, which improves separability and suppresses the occurrence of jams.)

The nip forming means 5 has a low-friction member 8 at a position in contact with the inner surface 21 of the fixing member 2 (the surface on the nip forming means 5 side). The low-friction member 8 has a fabric member 81 impregnated with a lubricant, which supplies lubricant to the inner surface 21 of the fuser member 2 and functions as a supply means. Examples of lubricants include silicone oil and grease. Details of the low-friction member 8 will be described later.

The fixing member 2 rotates together with the rotation of the pressure member 4 . In the embodiment shown in FIG. 1, the pressure member 4 is rotated by the driving source, and the driving force is transmitted to the belt at the nip portion N, thereby rotating the fixing member 2 . The fixing member 2 is nipped in the nip portion N and rotated, and is guided by the holding members inserted into both ends of the portion other than the nip portion N and travels.

With the above configuration, it is possible to realize a fixing device that is inexpensive and warms up quickly.

[Image forming apparatus]
Next, the configuration of the image forming apparatus 100 using the configuration described above will be described with reference to FIG.

The image forming apparatus 100 shown in FIG. 2 is a color printer using a tandem system in which image forming units for forming a plurality of color images are arranged side by side along the stretching direction of the belt. The present invention is not limited to this method, and can be applied not only to printers but also to copying machines, facsimile machines, and the like.

In FIG. 2, image forming apparatus 100 includes photosensitive drums 20Y, 20C, and 20M as image carriers capable of forming images corresponding to colors separated into yellow, cyan, magenta, and black. A tandem structure in which 20Bk is arranged side by side is adopted.

In the image forming apparatus 100 configured as shown in FIG. 2, the visible images formed on the respective photoreceptor drums 20Y, 20C, 20M and 20Bk face the respective photoreceptor drums 20Y, 20C, 20M and 20Bk in the direction of the arrow A1. A primary transfer process is performed on an intermediate transfer member (hereinafter referred to as a transfer belt) 11 using an endless belt that can be moved to superimpose each image. After that, a secondary transfer process is performed on the recording paper S, such as a recording sheet, so that the images are collectively transferred.

Around the photosensitive drums 20Y, 20C, 20M and 20Bk, image forming means are arranged for image forming processing according to the rotation of the photosensitive drums 20Y, 20C, 20M and 20Bk. Here, when the photosensitive drum 20Bk for forming a black image is described as an object, a charging device 30Bk for performing an image forming process along the rotation direction of the photosensitive drum 20Bk, a developing device 40Bk, a primary transfer roller 12Bk, A cleaning device 50Bk is arranged. An optical writing device 60 is used for writing after charging.

In the superimposed transfer onto the transfer belt 11, the visible images formed on the respective photosensitive drums 20Y, 20C, 20M, and 20Bk are superimposed and transferred to the same position on the transfer belt 11 while the transfer belt 11 moves in the A1 direction. be done. That is, voltage is applied by the primary transfer rollers 12Y, 12C, 12M, and 12Bk arranged facing the respective photosensitive drums 20Y, 20C, 20M, and 20Bk with the transfer belt 11 interposed therebetween. The timing is shifted toward

The photosensitive drums 20Y, 20C, 20M, and 20Bk are arranged in this order from the upstream side in the A1 direction. Photoreceptor drums 20Y, 20C, 20M, and 20Bk are provided in image stations for forming yellow, cyan, magenta, and black images, respectively.

The image forming apparatus 100 includes four image stations that perform image forming processing for each color, and is arranged above the photosensitive drums 20Y, 20C, 20M, and 20Bk so as to face each other. , 12C, 12M, and 12Bk; a secondary transfer roller 14, which is a transfer roller as a transfer member that is arranged to face the transfer belt 11 and follows and rotates with the transfer belt 11; An intermediate transfer belt cleaning device 13 is disposed facing the transfer belt 11 to clean the transfer belt 11, and an optical writing device serving as an optical writing device is disposed facing the lower portion of these four image stations. a device 60;

The optical writing device 60 is equipped with a semiconductor laser as a light source, a coupling lens, an f.theta. The optical writing device 60 supplies writing light Lb corresponding to each color to each of the photosensitive drums 20Y, 20C, 20M, and 20Bk (in FIG. 2, for the sake of convenience, only the black image image station is labeled). However, other image stations are substantially the same) to form electrostatic latent images on the photosensitive drums 20Y, 20C, 20M, and 20Bk.

The image forming apparatus 100 includes a sheet feeding device 70 as a sheet feeding cassette on which the recording sheet S conveyed between the photosensitive drums 20Y, 20C, 20M, and 20Bk and the transfer belt 11 is stacked; The recording paper S conveyed from the feeding device 70 is transferred to the transfer section between each of the photosensitive drums 20Y, 20C, 20M, and 20Bk and the transfer belt 11 at a predetermined timing that matches the formation timing of the toner image by the image station. and a sensor (not shown) for detecting that the leading edge of the recording paper S has reached the registration roller pair 810 .

The image forming apparatus 100 includes a fixing device 1 as roller fixing means for fixing the toner image onto the recording paper S to which the toner image has been transferred, and a body of the image forming device 100 for fixing the fixed recording paper S. a paper ejection roller 820 for ejecting to the outside, a paper ejection tray 83 disposed on the upper part of the main body of the image forming apparatus 100 for stacking the recording paper S ejected to the outside of the main body of the image forming apparatus 100 by the paper ejection roller 820; Toner bottles 9Y, 9C, 9M, and 9Bk filled with yellow, cyan, magenta, and black toners are provided below the discharge tray 83 .

The transfer belt unit 10 includes the transfer belt 11, primary transfer rollers 12Y, 12C, 12M, and 12Bk, as well as a driving roller 15 and a driven roller 16 around which the transfer belt 11 is wound.

The driven roller 16 also functions as a tension biasing means for the transfer belt 11, and for this reason, the driven roller 16 is provided with biasing means using a spring or the like. The transfer belt unit 10, the primary transfer rollers 12Y, 12C, 12M, 12Bk, the secondary transfer roller 14, and the cleaning device 13 constitute the transfer device 10A.

The sheet feeding device 70 is arranged in the lower part of the main body of the image forming apparatus 100 and has a feeding roller 84 as a feeding roller that contacts the upper surface of the uppermost recording sheet S. As shown in FIG. By rotating the feeding roller 84 in the counterclockwise direction, the uppermost recording sheet S is fed toward the registration roller pair 810 .

Although not shown in detail, the cleaning device 13 provided in the transfer device 10A has a cleaning brush and a cleaning blade arranged to face and contact the transfer belt 11 . The transfer belt 11 is cleaned by scraping and removing foreign matter such as residual toner on the transfer belt 11 with a cleaning brush and a cleaning blade.

The cleaning device 13 has discharge means (not shown) for carrying out and discarding residual toner removed from the transfer belt 11 .

The image forming apparatus 100 further includes an operation panel (not shown) for operating the entire apparatus, and control means (not shown) for controlling the entire apparatus.

When the number of sheets passed, the operation time, the number of revolutions of the fixing member 2, and the like exceed a predetermined value, the control means causes the operation panel to display that maintenance of the fixing member 2 is required (maintenance display). It functions as display means. That is, the control means causes the operation panel to display the necessity of maintenance at predetermined operation intervals. When the maintenance is performed, the control unit stops the maintenance display and restarts counting the number of sheets passed, the operation time, the number of revolutions of the fixing member 2, and the like.

[Low friction member]
Details of the low-friction member 8 in the fixing device 1 will now be described with reference to FIGS. The low-friction member 8 has a woven fabric member 81 which is a single continuous sheet-like member, and holding means 82 around which the woven fabric member 81 is wound.

The woven fabric member 81 is formed in a rectangular shape (strip shape) whose short side direction is the rotation direction of the fixing member 2 and whose long side direction is the width direction. A central portion of the fabric member 81 in the rotational direction serves as a contact area 81A that contacts the inner surface 21 of the fixing member 2, and both ends in the rotational direction serve as held areas 81B and 81C held by the holding means .

Four held portions 811 to 814 aligned in the width direction are formed in the held region 81B on the upstream side in the rotational direction. The held portions 811 to 814 are rectangular through holes. One held portion 815 is formed in the held region 81C on the downstream side in the rotation direction. The held portion 815 is a rectangular through hole extending in the width direction.

The holding means 82 is configured separately from the main body of the nip forming means 5 and is fixed to the main body, and is formed in a rectangular plate shape with the width direction as the long side direction. The holding means 82 overlaps the surface (non-contact surface) of the fabric member 81 opposite to the contact surface with the inner surface 21 at the contact area 81A. Alternatively, the fabric member 81 may be directly wound around the main body of the nip forming means 5 so that the main body functions as the holding means. The holding means 82 is made of a member such as resin or metal that is less prone to thermal contraction than the fabric member 81 .

Eight holding portions 821 to 828 are formed on the surface of the holding means 82 opposite to the surface overlaid on the fabric member 81 . The holding portions 821 to 828 are protrusions formed in the shape of a quadrangular prism. The widthwise dimension of the holding portions 821 to 828 is substantially equal to or slightly smaller than the widthwise dimension of the held portions 811 to 814 . The rotational dimensions of the holding parts 821 to 828 are substantially equal to or slightly smaller than the rotational dimensions of the held parts 811 to 815 .

The distance L1 between one side edge of the holding portions 821 and 825 on one side in the width direction (left side in FIG. 3) and the other side edge of the holding portions 824 and 828 on the other side in the width direction (right side in FIG. 3) is , is smaller than the width dimension L2 of the held portion 815 . Let ΔL be half the difference between the distance L1 and the dimension L2.

With the holding means 82 superimposed on the non-contact surface of the fabric member 81 as described above, the held areas 81B and 81C of the fabric member 81 are folded back toward the holding means 82 (front side in FIG. Holding portions 821 to 824 are inserted through holding portions 811 to 814, respectively, and holding portions 825 to 828 are inserted through held portion 815, respectively. Thereby, the fabric member 81 is held by the holding means 82 .

Between the holding portions 825 and 828 at both ends in the width direction and the inner edge of the held portion 815, a gap of size ΔL is formed on one side in the width direction. Therefore, the fabric member 81 can shrink by the dimension ΔL on one side in the width direction in the downstream held region 81C. In other words, the woven fabric member 81 is restricted from contraction larger than the dimension ΔL on one side in the width direction in the held region 81C. The gap between the holding portion 825 and the inner edge of the held portion 815 and the gap between the holding portion 828 and the inner edge of the held portion 815 may be slightly different.

On the other hand, since the widthwise dimension of the holding portions 821 to 828 is substantially equal to or slightly smaller than the widthwise dimension of the held portions 811 to 814, the fabric member 81 almost contracts in the upstream held region 81B. shrinkage is regulated. Thus, the holding means 82 holds the fabric member 81 so as to restrict shrinkage in the width direction, and the restriction force on the upstream side is stronger than the restriction force on the downstream side.

When the fixing device 1 operates, the temperature of the fixing member 2 rises due to the heat generated by the heat source 3 and the frictional heat generated in each part, and the fabric member 81 in contact with the fixing member 2 is also heated and tries to thermally shrink. At this time, as described above, the woven fabric member 81 is restricted from shrinking in the width direction by the holding means 82, and the restricting force on the upstream side is stronger than the restricting force on the downstream side. The warp yarn 816 and the plurality of weft yarns 817 are shaped as shown in FIG. Although FIG. 4 shows the inner surface 21 of the fixing member 2 and the fabric member 81 is not actually visible, the fabric member 81 is shown superimposed on the inner surface 21 for convenience of explanation.

The plurality of warp yarns 816 , except for those arranged at the center in the width direction, extend obliquely from the ends in the width direction toward the center from the upstream side to the downstream side in the rotation direction of the fixing member 2 . exist. The lubricant adhering to the inner surface 21 of the fixing member 2 is guided by the warp threads 816 and moves along the extending direction of the warp threads 816 when the fixing member 2 rotates and passes through the nip portion N. On the other hand, the plurality of wefts 817 are curved in a convex shape toward the upstream side in the rotation direction, and the apex of the convex shape is located in the central portion in the width direction. The curvature of the weft yarn 817 increases toward the widthwise end portion side.

A plurality of warp yarns 816 are arranged along the width direction, and the inclination angle θ with respect to the rotation direction increases toward the ends of the warp yarns in the width direction. Assuming that the size of the contact area 81A in the rotational direction is S, the lubricant guided by the warp yarns 816 moves toward the center in the width direction by Stan θ. When the fixing member 2 does not come into contact with the fabric member 81 other than at the nip portion N, or when the pressing force is small even if it comes into contact, the nip width (the dimension of the nip portion N in the rotation direction) is set to LN, and the warp threads 816 may move toward the central portion in the width direction by LN tan θ.

The fabric member 81 has a plurality of weft threads 817 of different colors. In the illustrated example, four of the five wefts 817 indicated by solid lines are black, and one indicated by broken lines is red. The plurality of weft threads 817 may be composed of three or more colors.

Assuming that the size of the weft 817 in the direction of rotation (amount of curvature from the central portion in the width direction to the end portion) is L0, the size of the weft 817 in the direction of rotation L0 is preferably 8 to 40% of the size S of the contact area 81A in the direction of rotation. . Further, when the width of the contact area 81A is W, the rotation direction dimension L0 of the weft yarn 817 is preferably 0.4 to 2% of the width W.

According to this embodiment, the following effects are obtained. That is, the fabric member 81 in contact with the inner surface 21 of the fixing member 2 is held by the holding means 82 , so that the warp threads 816 are stretched from the upstream side to the downstream side in the rotation direction of the fixing member 2 . sloping from the center to the center. Therefore, the lubricant adhering to the inner surface 21 of the fixing member 2 is guided toward the central portion in the width direction when the fixing member 2 rotates.

As a result, the lubricant is prevented from flowing toward the width direction end portions of the fixing member 2, and leakage of the lubricant is suppressed. At this time, since it is not necessary to absorb the lubricant in order to suppress leakage of the lubricant, the total amount of the lubricant on the inner surface 21 of the fixing member 2 is unlikely to decrease. Therefore, shortage of the lubricant is unlikely to occur on the inner surface 21 of the fixing member 2, and sliding resistance when the fixing member 2 rotates can be kept low.

Also, the fabric member 81 may be attached with a slight inclination with respect to its original position due to manufacturing errors or the like. For example, the warp yarns 816 arranged in the center in the width direction may be inclined with respect to the rotation direction. In such a case, although the position where the lubricant gathers is slightly deviated from the central portion in the width direction, leakage of the lubricant from the end portions of the fixing member 2 is suppressed, and shortage of the lubricant is less likely to occur.

Furthermore, since the plurality of warp threads 816 located closer to the ends in the width direction have a larger inclination angle θ, the lubricant tends to flow toward the center particularly at the ends in the width direction. leakage of the lubricant can be further suppressed.

Further, since the weft yarns 817 of the fabric member 81 are convexly curved toward the upstream side in the rotation direction, the degree of this curvature can be measured and the inclination angle θ of the warp yarns 817 can be managed. In addition, since the curvature of the weft yarn 817 increases toward the end portion in the width direction, it is easy to increase the inclination angle θ of the plurality of warp yarns 816 closer to the end portion in the width direction.

Furthermore, since the fabric member 81 has a plurality of wefts 817 of different colors, the shape of the wefts 817 can be easily recognized and the amount of curvature of the wefts 817 can be easily measured.

Further, since the woven fabric member 81 is one continuous sheet-like member, it is possible to suppress the leakage of the lubricant from the gaps between the sheets.

[Second embodiment]
The fixing device of this embodiment includes a fixing member 2, a heat source 3, a pressure member 4, and a nip forming means, as in the first embodiment. In this embodiment, the nip forming means is different from that in the first embodiment.

Thus, in this embodiment the low friction member of the nip forming means comprises a fabric member 91 as shown in FIG. 6 and a retaining means 92 as shown in FIGS.

The woven fabric member 91 is formed in a rectangular shape (belt shape) with the rotation direction of the fixing member 2 as the short side direction and the width direction as the long side direction. A central portion of the fabric member 91 in the rotational direction serves as a contact area 91A that contacts the inner surface 21 of the fixing member 2, and both ends in the rotational direction serve as held areas 91B and 91C held by the holding means 92. FIG.

In each of the held areas 91B and 91C, a plurality of held parts 911 (10 upper and lower parts in the illustrated example) are formed along the width direction. The held portion 911 is a rectangular through-hole. The plurality of held portions 911 have a linear arrangement shape (first shape).

The holding means 92 is configured separately from the main body of the nip forming means 5 and is fixed to the main body, and is formed in a rectangular plate shape with the width direction as the long side direction. The holding means 92 overlaps the surface (non-contact surface) of the fabric member 91 opposite to the contact surface with the inner surface 21 in the contact area 91A. Alternatively, the fabric member 91 may be directly wound around the main body of the nip forming means 5 so that the main body functions as the holding means.

A plurality of holding portions 921 (20 pieces in total in the illustrated example) are formed on the surface of the holding means 92 opposite to the surface overlaid on the fabric member 91 . The holding portion 921 is a projection formed in an elliptical cylinder shape. The plurality of holding portions 921 are arranged in two rows, and each row has an arrangement shape (second shape) along the width direction and convexly curved toward the upstream side in the rotation direction.

In the state where the holding means 92 is superimposed on the non-contact surface of the fabric member 91 as described above, the held areas 91B and 91C of the fabric member 91 are folded back toward the holding means 92 to be held by the held portions 911 respectively. Each of the portions 921 is inserted.

At this time, since the first arrangement shape of the held portions 911 and the second arrangement shape of the holding portions 921 are different from each other, the fabric member 91 is deformed before and after being held. A plurality of warp yarns 916 and a plurality of weft yarns 917 forming the fabric member 91 are shaped as shown in FIG. Although FIG. 9 shows the inner surface 21 of the fixing member 2 and the fabric member 91 cannot be seen in reality, the fabric member 91 is shown superimposed on the inner surface 21 for convenience of explanation.

The plurality of warp yarns 916 and the plurality of weft yarns 917 of this embodiment have the same shape as the plurality of warp yarns 816 and the plurality of weft yarns 817 of the first embodiment.

In this embodiment, the first array shape of the held portions 911 is linear and the second array shape of the holding portions 921 is curved. Just do it. For example, the first array shape of the held portions may be curved in a convex shape toward the downstream side, and the second array shape of the holding portions may be linear. Further, the first array shape of the held portions may be a shape curved to project downstream, and the second array shape of the holding portions may be a shape curved to project upstream.

According to this embodiment, the following effects are obtained. That is, the woven fabric member 91 in contact with the inner surface 21 of the fixing member 2 is held by the holding means 92, so that the warp threads 916 are stretched from the upstream side to the downstream side in the rotation direction of the fixing member 2 so that the ends in the width direction are aligned. sloping from the center to the center. Therefore, the lubricant adhering to the inner surface 21 of the fixing member 2 is guided toward the central portion in the width direction when the fixing member 2 rotates.

As a result, the lubricant is prevented from flowing toward the width direction end portions of the fixing member 2, and leakage of the lubricant is suppressed. At this time, since it is not necessary to absorb the lubricant in order to suppress leakage of the lubricant, the total amount of the lubricant on the inner surface 21 of the fixing member 2 is unlikely to decrease. Therefore, shortage of the lubricant is unlikely to occur on the inner surface 21 of the fixing member 2, and sliding resistance when the fixing member 2 rotates can be kept low.

Also, the fabric member 91 may be attached with a slight inclination with respect to its original position due to manufacturing error or the like. For example, the warp yarns 916 arranged in the central portion in the width direction may be inclined with respect to the rotation direction. In such a case, although the position where the lubricant gathers is slightly shifted from the central portion in the width direction, leakage of the lubricant from the end portions of the fixing member 2 is suppressed, and shortage of the lubricant is less likely to occur.

It should be noted that the present invention is not limited to the above-described embodiments, but includes other configurations and the like that can achieve the object of the present invention, and the following modifications and the like are also included in the present invention.

For example, in the first embodiment, the plurality of warp threads 816 have a larger inclination angle θ as they are positioned closer to the end in the width direction, but the present invention is not limited to such a configuration. The plurality of warp yarns 816 may have the same degree of inclination angle θ except for the warp yarns 816 in the central portion, or the warp yarns 816 on the end side may have a smaller inclination angle θ. The size of the inclination angle .theta. may be set appropriately as long as it corresponds to the inclination of the fabric member 81 that may occur during manufacturing.

In the first embodiment, the fabric member 81 has a plurality of wefts 817 of different colors. may be of the same color. For example, even if a plurality of wefts have the same color, the shape of the wefts can be visually observed and the amount of curvature can be easily measured depending on the thickness and luster of the yarn, the roughness of the weave, and the like. In addition, even when it is easy to manage the amount of curvature in fabric manufacturing, or when the error in the amount of curvature is small, a plurality of wefts may have the same color.

Further, in the first embodiment, the curvature of the weft yarn 817 is set to increase toward the widthwise end portion, but the curvature of the weft yarn may be set so that the warp yarn has an appropriate inclination angle. For example, it may be substantially constant from the central portion to the end portions in the width direction.

Further, in the first embodiment, the woven fabric member 81 functions as supply means for supplying the lubricant to the inner surface 21 of the fixing member 2, but the supply means is provided separately from the member constituting the contact portion. may be provided.

In addition, although the best configuration, method, etc. for carrying out the present invention have been disclosed in the above description, the present invention is not limited thereto. That is, although the present invention has been particularly illustrated and described primarily with respect to certain embodiments, it is possible to apply the invention to such embodiments without departing from the spirit and scope of the invention. Various modifications can be made by the trader.

Therefore, the descriptions limited to the shapes, materials, etc. disclosed above are provided as examples to facilitate understanding of the present invention, and are not intended to limit the present invention. The description by the name of the member that removes some or all of the limitations on the shape, material, etc. is included in the present invention.

REFERENCE SIGNS LIST 1 fixing device 2 fixing member 21 inner surface 3 heat source 4 pressure member 5 nip forming means 5A, 5B contact portion 8 low-friction member (feeding means)
81, 91 fabric members 82, 92 holding means 816, 916 warp yarns 817, 917 weft yarns 911 held portion 921 holding portion 100 image forming apparatus

Japanese Patent Application Laid-Open No. 2008-26603

Claims (7)

A pressing member, an endless cylindrical fixing member provided opposite to the pressing member, a heat source for heating the fixing member, and arranged on the opposite side of the pressing member with the fixing member interposed therebetween. and a nip forming means for forming a nip portion by:
The nip forming means has a woven fabric member that contacts the inner surface of the fixing member on the nip forming means side and supplies a lubricant to the inner surface, and a holding means that holds the woven fabric member,
The holding means is configured such that at least the warp yarns on both sides in the width direction of the woven fabric member are inclined from the ends in the width direction toward the center portion from the upstream side to the downstream side in the rotation direction of the fixing member, holding the fabric member;
The holding means holds the woven fabric member so as to restrict shrinkage in the width direction, and the restriction force on the upstream side is stronger than the restriction force on the downstream side.
A fixing device characterized by: A pressing member, an endless cylindrical fixing member provided opposite to the pressing member, a heat source for heating the fixing member, and arranged on the opposite side of the pressing member with the fixing member interposed therebetween. and a nip forming means for forming a nip portion by:
The nip forming means has a woven fabric member that contacts the inner surface of the fixing member on the nip forming means side and supplies a lubricant to the inner surface, and a holding means that holds the woven fabric member,
The holding means is configured such that at least the warp yarns on both sides in the width direction of the woven fabric member are inclined from the ends in the width direction toward the center portion from the upstream side to the downstream side in the rotation direction of the fixing member, holding the fabric member;
The fabric member has a plurality of held portions arranged in a predetermined first shape along the width direction,
The holding means has a plurality of holding portions arranged in a predetermined second shape along the width direction,
Since the first shape and the second shape are different, the wefts of the fabric member are convexly curved toward the upstream side, and the warps are inclined.
A fixing device characterized by: In the fabric member held by the holding means, the warp threads guide the lubricant from the widthwise end portions toward the center portion when the fixing member rotates. Item 3. The fixing device according to Item 1 or 2 . 4. The fabric member held by the holding means, wherein the warp yarns located closer to the ends in the width direction have a greater inclination angle with respect to the rotating direction . 2. The fixing device according to item 1 . In the woven fabric member held by the holding means, the weft yarn of the woven fabric member is convexly curved toward the upstream side in the rotation direction, and the curvature increases toward the end portions in the width direction. The fixing device according to any one of claims 1 to 4 . The fixing device according to any one of claims 1 to 5 , wherein the fabric member is a single continuous sheet-like member. An image forming apparatus comprising the fixing device according to any one of claims 1 to 6 .

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