JP7139891B2 - Fixing device and image forming device - Google Patents

Description

The present invention relates to fixing devices and image forming apparatuses.

2. Description of the Related Art In recent years, there has been a strong market demand for energy saving and high speed image forming apparatuses such as printers, copiers, and facsimiles.
In an image forming apparatus, an unfixed toner image is transferred to a recording material sheet, printing paper, photosensitive paper, electrostatic recording paper, etc. by an image transfer method or a direct method through image forming processes such as electrophotographic recording, electrostatic recording, and magnetic recording. It is formed on the recording material. As a fixing device for fixing an unfixed toner image, a contact heating type fixing device such as a heat roller type, a film heating type, or an electromagnetic induction heating type is widely used. As an example of such a fixing device, a belt type fixing device and a surf fixing (film fixing) fixing device using a ceramic heater are known.

FIG. 11 is a schematic diagram of a conventional fixing device. A pipe-shaped metal heat conductor 2 is fixed inside the endless belt 1 so as to be able to guide the movement of the endless belt 1, and a heat source 3 inside the metal heat conductor 2 heats the endless heat through the metal heat conductor 2. Heat the belt 1. Further, a pressure roller 4 is provided to form a nip portion N in contact with the metal heat conductor 2 through the endless belt 1, and the endless belt 1 is moved in the circumferential direction so as to rotate together with the rotation of the pressure roller 4. Let With this configuration, it is possible to heat the entire endless belt that constitutes the fixing device, shorten the first print time from the standby time for heating, and solve the shortage of heat during high-speed rotation. there is

In such a fixing device, a sheet impregnated with oil is placed on the surface of the stay member in order to increase the slidability between the stay member and the endless belt (fixing member) for forming a nip (for example, patent document Literature 1)

As described above, by adopting a configuration in which the endless belt is directly heated, energy saving is high, and it is possible to further shorten the first print time from the time of waiting for heating. However, when a sheet impregnated with oil is arranged on the surface of the stay member in order to increase the slidability between the stay member and the endless belt (fixing member) for forming the nip, as in Patent Document 1, the oil is not absorbed. Insufficient retention may result in leakage from the ends over time. As a result, a new problem arises that sliding resistance increases and torque increases.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a fixing device capable of improving durability by increasing oil retention of a sheet.

A fixing device according to an aspect of the present invention includes a rotatable fixing member, a heat source that heats the fixing member, a pressure member that forms a nip with the fixing member, and the pressure member inside the fixing member. and a fiber sheet impregnated with a lubricant for enhancing slidability between the nip forming member and the fixing member, wherein the fiber sheet is provided with the fixing member. The fixing device is characterized in that the fixing force of the fiber sheet at the ends in the axial direction is held by fixing holding means that is smaller than that in the central portion in the axial direction of the fixing member.

According to one aspect of the present invention, durability can be enhanced by enhancing the oil retention of the sheet.

1 is a diagram illustrating an example of an image forming apparatus equipped with a fixing device according to an exemplary embodiment; FIG. 2 is a cross-sectional configuration diagram of a fixing device; FIG. It is a top view of a light-shielding member. It is a figure which shows the state which rotated the light-shielding member to the position corresponding to A3 paper. It is a figure which shows the state which rotated the light-shielding member to the position corresponding to a postcard. FIG. 10 is a conceptual diagram for explaining oil leakage in a fixing device using a sliding sheet of conventional configuration; FIG. 10 is a diagram showing the relationship between a conventional sliding sheet and double-sided tape; FIG. 4 is a diagram showing the relationship between the sliding sheet and the double-sided tape in this embodiment. It is a figure which shows the example of the detailed flow of the oil at the time of comprising a double-sided tape like the upper part of FIG.8(b). It is a figure which shows the example of the detailed flow of the oil at the time of comprising a double-sided tape like the lower part of FIG.8(b). 1 is a schematic diagram of a conventional fixing device; FIG.

Embodiments of a fixing device and an image forming apparatus will be described in detail below with reference to the accompanying drawings. First, an example of an image forming apparatus equipped with a fixing device according to the present embodiment will be described with reference to FIG.

The illustrated image forming apparatus is a color printer that uses a tandem system in which image forming units that form a plurality of color images are arranged side by side along the direction in which the belt is stretched. It is also possible to target copiers, facsimile machines, and the like.

In the image forming apparatus 1000, photosensitive drums 20Y, 20C, 20M, and 20Bk are arranged as image carriers capable of forming images corresponding to colors separated into yellow, cyan, magenta, and black. A tandem structure is adopted.

In the illustrated configuration, the images formed on the photoreceptor drums 20Y, 20C, 20M, and 20Bk are transferred in the arrow A1 direction while facing the photoreceptor drums 20Y, 20C, 20M, and 20Bk by the execution of the primary transfer process. The image is superimposed and transferred onto an intermediate transfer member (hereinafter referred to as a transfer belt) 11 using a movable endless belt. After that, the image on the intermediate transfer member is collectively transferred to the recording material S such as a recording sheet by executing the secondary transfer process.

A device for forming an image according to the rotation of the photoreceptor drum is arranged around each photoreceptor drum. Taking the photoreceptor drum 20Bk that forms a black image as an example, a charging device 30Bk, a developing device 40Bk, a primary transfer roller 12Bk, and a cleaning device 50Bk are arranged along the rotation direction of the photoreceptor drum 20Bk. It is An optical writing device 8 is used for writing after the photosensitive drum is charged.

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. By applying voltage from the primary transfer rollers 12Y, 12C, 12M, and 12Bk disposed facing the respective photosensitive drums 20Y, 20C, 20M, and 20Bk across the transfer belt 11, the A1 direction upstream side , the timing is shifted from the downstream side to the downstream side.

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 1000 is arranged above four image stations that perform image forming processing for each color, facing each of the photosensitive drums 20Y, 20C, 20M, and 20Bk. , 12C, 12M, and 12Bk, a secondary transfer roller 5 which is a transfer roller as a transfer member which is arranged to face the transfer belt 11, follows the transfer belt 11, and rotates with the transfer belt 11; It has a cleaning device 13 arranged to face the transfer belt 11 to clean the transfer belt 11, and an optical writing device 8 as an optical writing device arranged to face below these four image stations. is doing.

The optical writing device 8 includes a semiconductor laser as a light source, a coupling lens, an f.theta. The optical writing device 8 emits writing light Lb corresponding to each color to each of the photosensitive drums 20Y, 20C, 20M and 20Bk to form electrostatic latent images on the photosensitive drums 20Y, 20C, 20M and 20Bk. is configured to As for the writing light Lb, in FIG. 1, for the sake of convenience, only the black image image station is labeled, but the other image stations are the same.

The image forming apparatus 1000 includes a sheet feeding device 61 as a paper feed cassette on which the recording material S conveyed between the secondary transfer roller 5 and the transfer belt 11 is stacked, and A pair of registration rollers 4 for feeding the recording material S received toward a transfer portion between the secondary transfer roller 5 and the transfer belt 11 at a predetermined timing corresponding to the timing of forming a toner image by the image station; A sensor (not shown) for detecting that the leading edge of the material S has reached the registration roller pair 4 is provided.

The image forming apparatus 1000 also includes a fixing device 100 for fixing the toner image onto the recording material S to which the toner image has been transferred, and ejects the recording material S on which the toner image has been fixed to the outside of the main body of the image forming apparatus 1000 . a paper discharge roller 7, a paper discharge tray 17 disposed in the upper part of the main body of the image forming apparatus 1000 and for stacking the recording material S discharged to the outside of the main body of the image forming apparatus 1000 by the paper discharge roller 7; 17, toner bottles 9Y, 9C, 9M, and 9Bk filled with yellow, cyan, magenta, and black toners are provided.

The transfer belt unit 10 includes the transfer belt 11, primary transfer rollers 12Y, 12C, 12M, and 12Bk, as well as a driving roller 72 and a driven roller 73 around which the transfer belt 11 is wound.

The driven roller 73 also functions as tension biasing means for the transfer belt 11, and for this purpose, the driven roller 73 is provided with biasing means using a spring or the like. The transfer belt unit 10, the primary transfer rollers 12Y, 12C, 12M and 12Bk, the secondary transfer roller 5, and the cleaning device 13 constitute a transfer device 71. As shown in FIG.

The sheet feeding device 61 is arranged in the lower part of the main body of the image forming apparatus 1000, and has a feeding roller 3 that abuts on the upper surface of the uppermost recording material S, and the feeding roller 3 rotates counterclockwise. By being driven, the uppermost recording material S is fed toward the registration roller pair 4 .

Although not shown in detail, the cleaning device 13 provided in the transfer device 71 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 also has discharge means (not shown) for carrying out and discarding residual toner removed from the transfer belt 11 .

FIG. 2 is a cross-sectional configuration diagram of the fixing device. The fixing device 100 of the present embodiment has a pressure roller 131 which is a pressure rotating member and a fixing belt 121 which is a fixing member. heated. It also has a temperature sensor that faces the outer peripheral surface of the fixing belt 121 and detects the temperature of the fixing belt 121 .

Inside the loop of the fixing belt 121 (inside the fixing member), there is a nip forming member 204 that forms a nip by being pressed against the pressing roller 131 facing the fixing belt via the fixing belt. 201 to indirectly slide. Although the shape of the nip portion N is flat in FIG. 2, it may be concave or other shapes. (If the nip has a concave shape, the discharge direction of the leading edge of the recording paper will be closer to the pressure roller, and the separability will be improved, thereby suppressing the occurrence of a jam).

The fixing belt 121 is an endless belt (or film) using a metal belt such as nickel or SUS or a resin material such as polyimide. The surface layer of the belt has a release layer such as a PFA or PTFE layer, and has a release property so that the 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. If there is no silicone rubber layer, the heat capacity is reduced and the fixability is improved. There is a problem that gloss unevenness (yuzu skin image) remains. In order to improve this, it is necessary to provide a silicone rubber layer of 100 [μm] or more. Deformation of the silicone rubber layer absorbs minute irregularities and improves the yuzu skin image.

A support member 205 (stay) for supporting the nip forming member 204 is provided inside the fixing belt 121 to prevent bending of the nip forming member 204 that receives pressure from the pressure roller 131, thereby achieving a uniform nip width in the axial direction. is obtained. Both ends of the support member 205 are fixed and positioned by flanges (not shown) that are holding members. Moreover, a reflecting member 206 is provided between the heat source 203 and the support member 205 to suppress wasteful energy consumption due to the support member 205 being heated by radiant heat from the heat source 203 or the like. Here, the same effect can be obtained even if the surface of the supporting member 205 is heat-insulated or mirror-finished instead of providing the reflecting member 206 . The heat source 203 may be the illustrated halogen heater, but may also be an induction heating device, a resistance heating element, a carbon heater, or the like.

The pressure roller 131 has an elastic rubber layer 133 on a core metal 132, and a release layer (PFA or PTFE layer) is provided on the surface to obtain release properties. The pressure roller 131 is rotated by a driving force transmitted through a gear from a driving source such as a motor provided in the image forming apparatus. Further, the pressure roller 131 is pressed against the fixing belt 121 side by a spring or the like, and has a predetermined nip width due to the elastic rubber layer 133 being crushed and deformed. The pressure roller 131 may be a hollow roller, and the pressure roller 131 may have a heating source such as a halogen heater. The elastic rubber layer 133 may be made of solid rubber, but if there is no heat source such as a heater inside the pressure roller 131, sponge rubber may be used. Sponge rubber is more desirable because it has a higher heat insulating property and makes it more difficult for the fixing belt to lose heat.

The fixing belt 121 is rotated (driven) by the pressure roller 131 . In the case of this embodiment, the pressure roller 131 is rotated by a driving source (not shown), and driving force is transmitted to the belt at the nip portion N, thereby rotating the fixing belt 121 . The fixing belt 121 rotates while being nipped by the nip portion N, and runs while being guided by holding members (flanges) at both end portions other than the nip portion. With such a configuration, it is possible to realize a fixing device that is inexpensive and warms up quickly.

The fixing device shown in FIG. 2 also includes a movable light shielding member 210 for preventing temperature rise at the edge.

As shown in FIG. 3, the light shielding member 210 has an opening (non-light shielding portion) corresponding to the paper size. It is provided so as to rotate without contacting the belt. Then, by rotating the light shielding member 210 to a position corresponding to the width of the sheet, the light is shielded from the unnecessary area for heating. FIG. 4 shows a state in which the light blocking member 210 is rotated to a position corresponding to A3 paper. Also, FIG. 5 shows a state in which the light blocking member 210 is rotated to a position corresponding to the postcard.

By providing the light shielding member 210, even when narrow sheets of paper are continuously passed, the temperature of the non-sheet-passing area is not excessively increased. No control is required.

In the fixing device of the present embodiment, although not shown in the drawing, each heater of the two halogen heaters 203 has a distance relationship between the fixing belt 121 and the reflecting member 206 (distance L1 between the heater and the fixing belt, The distance L2) between the heater and the reflecting member satisfies L1<L2, and with this configuration, light can be efficiently irradiated to the fixing member regardless of the type of paper being passed. Next, the sliding sheet 201 will be described.

The sliding sheet 201 is composed of a fibrous sheet having a texture to reduce abrasion of the fixing belt 121. The sliding sheet 201 includes warp and weft impregnated with a lubricant such as oil. is woven with The means for attaching and fixing the sliding sheet 201 to the nip forming member 306 is not limited, but for example, it is wound around the nip forming member 204, and the nip forming member 204 is attached by adhesive means (e.g., double-sided tape) and fastening means (e.g., , screws). A case where a double-sided tape is used as the adhesive means will be described below.

The sliding sheet 201 is fixed to a heat equalizing plate (not shown) with double-sided tape for assembly. In this embodiment, at this time, a double-faced tape is attached to the central portion of the roller-shaped fixing belt 121 in the axial direction so that the heat equalizing plate and the sliding sheet 201 can be securely fixed, and the axial end portions are attached. Then, the sliding sheet 201 is not fixed by the double-sided tape, or is fixed by weakening the fixing force. In such a configuration, when the sliding sheet 201 is assembled and the fixing belt 121 is rotated, the portion of the sliding sheet 201 on the axial end side of the fixing belt 121 is pulled in the nip downstream direction, The sliding sheet 201 has an arch shape.

Specifically, the warp yarns on the front side of the end portion of the sliding sheet 201 are directed inward in the axial direction with respect to the conveying direction, and the warp yarns further downstream in the conveying direction are directed toward the center in the axial direction. By arranging the sliding sheet 201 in this manner, the oil impregnated in the sliding sheet 201 moves from the ends in the longitudinal direction of the shaft toward the center as the fixing belt 121 rotates. Therefore, it is possible to prevent an increase in torque due to leakage of oil from the end portion of the fixing belt 121 in the axial direction over time.

FIG. 6 is a conceptual diagram for explaining oil leakage in a conventional fixing device using a sliding sheet. As shown in FIG. 6, if the sliding sheet 601 having the conventional structure does not retain sufficient oil, oil leakage 602 may occur from the end of the fixing belt 121 in the axial direction over time. More specifically, in the conventional sliding sheet, a double-sided tape 701 is provided over both ends of the fixing belt 121 in the axial direction so that the portions to which the double-sided tape 701 is attached have substantially the same adhesive force. Therefore, centrifugal force or the like caused by the rotation of the fixing roller 121 may cause oil to leak from the end of the fixing belt 121 in the axial direction.

FIG. 7 is a diagram showing the relationship between a conventional sliding sheet and double-sided tape. FIG. 7(a) shows the relationship between the warp yarns 71 and the weft yarns 72 that constitute the sliding sheet. FIG. 7(b) shows the range where the sliding sheet is fixed with the double-sided tape. As shown in FIG. 7(a), in the conventional sliding sheet 601, the warp yarns 71 and the weft yarns 72 are woven so as to be perpendicular to each other, and the fixing belt 121 rotates in the running direction D1. The oil impregnated in 601 also flows in the direction of the warp and in substantially the same direction as the running direction D1 (D21-D23). FIG. 7(a) shows that the oil flows in substantially the same direction as the traveling direction D1 at both ends (D21, D23) and the central portion (D22) of the fixing belt 121 in the axial direction. ing.

Further, in FIG. 7B, the double-sided tape 701 is attached to substantially the entire surface of the nip forming member 204 in the axial direction of the fixing belt 121, and both ends and the central portion of the double-sided tape 701 are all covered. It can be seen that the force of the same magnitude is applied evenly.

FIG. 8 is a diagram showing the relationship between the sliding sheet and the double-sided tape in this embodiment. FIG. 8(a) shows the relationship between the warp yarns 81 and the weft yarns 82 that constitute the sliding sheet. FIG. 8(b) shows the range where the sliding sheet is fixed with the double-sided tape. The axial center portion of the fixing belt 121, which is a double-faced tape as a fixing and holding means, is configured to have a length of approximately 1/3 or more of the length of the nip forming member 204 in the width direction.

As shown in FIG. 8(a), in the sliding sheet 201 of this embodiment, the warp yarns 81 and the weft yarns 82 woven so as to be orthogonal to each other form an arch shape with the lowest point at the center. The oil with which the sliding sheet 201 is impregnated forms a predetermined angle toward the central portion, which is the inner side with respect to the running direction D1 of the fixing belt 121, at both ends (D31, D33) of the fixing belt 121 in the axial direction. It shows that the warp yarns 81 are inclined and that the warp yarns 81 and the running direction D1 of the fixing belt 121 at the central portion (D32) of the fixing belt 121 are substantially the same.

8B, the double-faced tape 801a is attached mainly to the central portion of the fixing belt 121 in the axial direction of the nip forming member 204, and both ends of the fixing belt 121 in the axial direction. The area to be pasted becomes smaller as it progresses. That is, the double-sided tapes 821a and 831a and the double-sided tapes 822a and 832a at both ends have a smaller area than the double-sided tape 811a at the center. As a result, a greater adhesive force is applied to the central portion of the double-sided tape 801a, and a smaller adhesive force is applied to both ends. Further, the distance X1 between the double-sided tape 821a and the double-sided tape 831a and the distance X3 between the double-sided tape 822a and the double-sided tape 832a are respectively the distance X2 between the double-sided tape 811a and the double-sided tape 821a in the central part and the distance X2 in the middle part. It is configured to be wider than the interval X4 between the double-sided tape 811a and the double-sided tape 822a.

That is, the double-faced tape 801a has a central portion in the axial direction central portion of the fixing belt 121 and first end side portions (821a, 822a) separated from the central portion by the first intervals (X2, X4). , the first end side portion and the second end portion side portions (831a, 832a) separated by the second distance (X1, X3), and the second distance is greater than the first distance is configured to be longer. In addition, the double-sided tape 801a is composed of a central portion (811a) in the axial central portion of the fixing belt 121 and end portions (821a and 831a, 822a and 832a) on the axial end side of the central portion. The widthwise length of the nip forming member 204 at the central portion is longer than the length of the end side portion.

In this way, the double-sided tape 801a as a fixing and holding means is arranged so that the force for fixing the fiber sheet by the double-sided tape becomes smaller toward the ends of the fixing belt 121 in the axial direction. 2, the adhesive force of the double-sided tape 801a is weaker at both ends in the axial direction of the fixing belt 121 than at the central portion. Therefore, as shown in FIG. 8A, the weft yarns 82 at both ends are bent in the running direction of the fixing belt 121, and the warp yarns 81 at both ends are bent by the force acting on the warp yarns 81 due to the bending. It becomes inclined toward the central part of the direction.

The range in which the sliding sheet 201 is fixed with the double-sided tape is not limited to the example shown in the upper part of FIG. 8B, and other methods shown in the lower part of FIG. 8B can also be adopted. 8B, both end portions 851 and 852 of the double-sided tape 801b have a triangular shape in which the downstream side of the nip, which is the downstream side of the running direction D1 of the fixing belt 121, is missing. It can be seen that the In this way, the double-faced tape 801b as a fixing and holding means has a smaller fixing force on the fiber sheet at the axial end of the fixing belt 121 on the downstream side of the nip than on the upstream side of the nip (or eliminates the fixing force). ), the contact area of both ends of the double-sided tape 801b is smaller than that of the central portion, and the fixing force on the downstream side of the nip is reduced (or the fixing force is eliminated), so that the sliding sheet The adhesive force with respect to 201 becomes smaller than that in the central portion, and the same effect as in the upper part of FIG. 8B can be obtained.

As shown in these embodiments, the fixing force of the sliding sheet is configured such that the fixing force of the fixing belt 121 is loose at both end portions of the fixing belt 121 with respect to the center portion in the axial direction, thereby obtaining the above effects. be able to. Further, since the double-sided tape is used as the fixing and holding means, the fixing force of the fiber sheet can be easily changed in the axial direction of the fixing belt 121 . Further, as shown in the lower part of FIG. 8B, even if the fixing force is not changed in the axial direction of the fixing belt 121, by changing the fixing force on the downstream side and the fixing force on the upstream side of the nip, the fixing force shown in FIG. 8(b) An arch shape similar to the upper case can be created.

FIG. 9 is a diagram showing an example of the detailed flow of oil when the double-sided tape is configured as shown in the upper part of FIG. 8(b). The left part of FIG. 9 shows a cross section of the nip portion of the fixing device 100, and the right part of FIG. showing relationships. With respect to the nip portion N, the portion 201a of the sliding sheet in the range corresponding to the position of the stuck double-sided tape 801a has a vertical length (length in the running direction D1) L, and the sliding sheet 201 is configured as the longitudinal length S.

As shown in the right part of FIG. 9, the oil 901a, 901c in the portion where the double-faced tape 801a is not attached flows in substantially the same direction as the running direction D1. However, it can be seen that the oil 901b near both ends of the portion 201a to which the double-sided tape 801a is attached flows toward the central portion near the center line C of the fixing belt 121 in the width direction. Note that FIG. 9 shows the configuration on the premise that the double-sided tape 801a is continuously attached across the width direction of the fixing belt 121, and the adhesive force becomes weaker as it advances to both ends of the fixing belt 121. , a double-sided tape having the structure shown in FIG.

FIG. 10 is a diagram showing an example of the detailed flow of oil when the double-sided tape is configured as shown in the lower part of FIG. 8(b). The left part of FIG. 10 shows a cross section of the nip portion of the fixing device 100, and the right part of FIG. It shows the relationship between the warp threads 81, the weft threads 81, and the oil in the right half. In the portion 201b of the sliding sheet 201 in the range corresponding to the position of the stuck double-sided tape 801b with respect to the nip portion N, since the adhesive force on the downstream side of the nip at the end (the right end in FIG. 10) is weak, the warp It can be seen that 81 is inclined toward the central portion side (left side in FIG. 10) in the axial direction by an angle θ (the length of Stan θ). In addition, the sliding sheet 201 is configured to have the vertical length S described above.

As shown in the right part of FIG. 10, the oil 1001a, 1001c in the portion where the double-sided tape 801b is not attached flows in substantially the same direction as the running direction D1. However, it can be seen that the portion 201b to which the double-sided tape 801b is attached flows toward the side near the center in the width direction of the fixing belt 121 (left side in FIG. 10). Further, in the portion 201b, since the oil flows toward the side near the center in the width direction of the fixing belt 121, more oil flows toward the region RA side near the center, and the end portions in the width direction of the fixing belt 121 It can be seen that less oil flows in the region RB on the side.

Thus, in this embodiment, the fixing belt 121 as a rotatable fixing member, the halogen heater 203 as a heat source for heating the fixing member, and the pressure roller as a pressure member forming a nip with the fixing member. 131, a nip forming member 204 facing the pressure member inside the fixing member to form a nip, and a fiber sheet impregnated with a lubricant to increase the slidability between the nip forming member and the fixing member. 3, the fiber sheet is held by the fixing and holding means in which the fixing force of the fiber sheet at the axial ends of the fixing member is smaller than that at the axial central portion of the fixing member. That is, by adopting the above-described configuration in which the fixed holding force of the double-faced tape at the sleeve axial end of the sliding sheet is reduced, when the sleeve such as the fixing belt is rotated, the sleeve axial direction end side is reduced. As the sliding sheet is pulled in the downstream direction of the nip, the axial end of the sliding sheet is arranged in the downstream direction, which is the running direction of the sleeve, rather than the central portion. Therefore, it is possible to improve oil retention in the fixing device and realize high durability.

The present invention is not limited to the above-described embodiment as it is, and in the implementation stage, the constituent elements may be modified and embodied within the scope of the gist thereof, or the plurality of constituent elements disclosed in the above-described embodiment may be modified. can be implemented in combination as appropriate.

1000 Image forming apparatus 100 Fixing device 121 Fixing belt 131 Pressure roller 201 Sliding sheet 203 Halogen heater (heat source)
204 nip forming member 205 supporting member 206 reflecting members 801a, 801b double-sided tape 81 warp 82 weft

JP 2009-109697 A

Claims (7)

a rotatable fixing member, a heat source for heating the fixing member, a pressure member forming a nip with the fixing member, and a nip forming member facing the pressure member inside the fixing member to form a nip. a fixing device having a fiber sheet impregnated with a lubricant for enhancing slidability between the nip forming member and the fixing member;
The fiber sheet is held by a fixing and holding means having a smaller fixing force at the axial end portions of the fixing member than at the axial center portion of the fixing member. The portion of the fiber sheet at the axial end of the member has a shape that is pulled in the downstream direction of the nip,
A fixing device characterized by: The fixing device according to claim 1,
The fixing and holding means is a double-sided tape,
The double-sided tape is arranged so that the fixing force of the fiber sheet by the double-sided tape becomes smaller toward the end in the axial direction.
A fixing device characterized by: a rotatable fixing member, a heat source for heating the fixing member, a pressure member forming a nip with the fixing member, and a nip forming member facing the pressure member inside the fixing member to form a nip. a fixing device having a fiber sheet impregnated with a lubricant for enhancing slidability between the nip forming member and the fixing member;
The fiber sheet is held by a fixing and holding means having a smaller fixing force at the axial end portions of the fixing member than at the axial center portion of the fixing member,
The fixing and holding means is a double-sided tape,
The double-sided tape is arranged so that the fixing force of the fiber sheet at the axial end portion by the double-sided tape is smaller on the downstream side of the nip than on the upstream side of the nip.
A fixing device characterized by: a rotatable fixing member, a heat source for heating the fixing member, a pressure member forming a nip with the fixing member, and a nip forming member facing the pressure member inside the fixing member to form a nip. a fixing device having a fiber sheet impregnated with a lubricant for enhancing slidability between the nip forming member and the fixing member;
The fiber sheet is held by a fixing and holding means having a smaller fixing force at the axial end portions of the fixing member than at the axial center portion of the fixing member,
The axial center portion of the fixing member of the fixing and holding means is configured to have a length of approximately 1/3 or more of the length of the nip forming member in the width direction,
A fixing device characterized by: a rotatable fixing member, a heat source for heating the fixing member, a pressure member forming a nip with the fixing member, and a nip forming member facing the pressure member inside the fixing member to form a nip. a fixing device having a fiber sheet impregnated with a lubricant for enhancing slidability between the nip forming member and the fixing member;
The fiber sheet is held by a fixing and holding means having a smaller fixing force at the axial end portions of the fixing member than at the axial center portion of the fixing member,
The fixing and holding means is a double-sided tape,
The double-sided tape is arranged so that the fixing force of the fiber sheet by the double-sided tape decreases toward the end in the axial direction,
The double-sided tape includes a central portion of the axially central portion, a first end side portion separated from the central portion by a first distance, and a second end portion separated from the first end side portion. and a second end portion spaced apart from the second interval, wherein the second interval is longer than the first interval,
A fixing device characterized by: a rotatable fixing member, a heat source for heating the fixing member, a pressure member forming a nip with the fixing member, and a nip forming member facing the pressure member inside the fixing member to form a nip. a fixing device having a fiber sheet impregnated with a lubricant for enhancing slidability between the nip forming member and the fixing member;
The fiber sheet is held by a fixing and holding means having a smaller fixing force at the axial end portions of the fixing member than at the axial center portion of the fixing member,
The fixing and holding means is a double-sided tape,
The double-sided tape is arranged so that the fixing force of the fiber sheet by the double-sided tape decreases toward the end in the axial direction,
The double-sided tape is composed of a central portion of the central portion in the axial direction and an end portion side portion closer to the end portion in the axial direction than the central portion. is longer than the length of the end portion,
A fixing device characterized by: An image forming apparatus comprising the fixing device according to any one of claims 1 to 6.

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