JP6784114B2 - Fixing device and image forming device - Google Patents

Description

The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile and a multifunction device thereof, and a fixing apparatus for fixing a toner image transferred to a recording medium in such an image forming apparatus to a recording medium. In particular, it includes a fixing belt that is wound so as to bridge the heating side member and the nip forming member, and a pressure member that is rotationally driven by pressure contacting the nip forming member so as to sandwich the fixing belt. In a state where tension is applied to the fixing belt by the pressing member, the fixing belt is pressed against the pressing member by the nip forming member and rotationally driven, and toner is applied to the nip portion where the fixing belt and the pressing member are pressed against each other. The fixing device for fixing an image on a recording medium is characterized in that the fixing device is miniaturized to reduce heat loss and the like during heat fixing to save energy.

Conventionally, in image forming devices such as copiers, printers, facsimiles, and multifunction devices thereof, a toner image transferred to a recording medium is fixed on the recording medium by a fixing device.

Then, in such a fixing device, when fixing the toner image transferred to the recording medium on the paper by heat and pressure, an endless fixing belt is urged by a pressing member in order to save energy. It is wound so as to be bridged between the heating roller and the heating side roller, and the pressurizing roller is rotationally driven in a state of being pressed against the heating side roller via this fixing belt, and the fixing belt and the pressurizing roller are pressed against each other. A toner image is fixed on a recording medium at the nip portion.

Further, in recent years, as shown in Patent Document 1, a fixing belt is provided so as to bridge between a fixing roller and a tension roller, and a tension applying member made of a tension spring is attached to one end of a holding member that holds the tension roller. In addition to allowing tension to act on the fixing belt, in a fixing device provided with a heating member inside the fixing belt, the holding member is rotated around a fulcrum provided at one point of the holding member, and tension is applied. It has been proposed that the tension roller is moved so that the fixing belt approaches the heating member when the applying member moves in the direction of applying tension.

However, in what is shown in Patent Document 1, a mechanism or the like for rotating a holding member that exerts tension on the tension roller is required, and a tension spring is used as the tension applying member, and the tension roller is formed by this tension spring. Since it is pulled, the fixing device becomes large, and since a fixing roller is used, there is a problem that heat loss during heat fixing also increases.

Further, in recent years, in order to save energy, for example, as shown in Patent Document 2, a heat-resistant elastic member is formed in a portion where the pressure roller is pressure-welded to form a nip instead of the fixing roller. There has been proposed a method in which a fixing belt is bridged between a fixing fixing member and a heating roller to apply tension to the fixing belt by using a fixing and fixing member that does not rotate.

However, in the one shown in Patent Document 2, a pressing member such as a spring is provided on the inner peripheral side of the fixing belt, and the pressing member urges the heating roller in a direction away from the fixing fixing member. In order to arrange the pressing member such as a spring on the inner peripheral side of the belt, it is necessary to pay attention to the arrangement of the peripheral members. For example, increase the distance between the fixing and fixing member and the heating roller so that the fixing member does not hit the spring. Is needed. As a result, it is necessary to increase the diameter of the fixing belt in the fixing device, which causes a problem that the fixing device becomes large and heat loss at the time of heating and fixing also increases.

Japanese Unexamined Patent Publication No. 2014-666902. Japanese Unexamined Patent Publication No. 2008-46663.

The present invention solves the above-mentioned problems in the fixing device for fixing the toner image transferred to the recording medium on the recording medium in the image forming device such as a copying machine, a printer, a facsimile and a multifunction device thereof. This is an issue.

Then, in the present invention, the fixing belt wound around the heating side member and the nip forming member is pressed against the nip forming member so as to sandwich the fixing belt, and the pressurization is rotationally driven. A member is provided, and in a state where tension is applied to the fixing belt by the pressing member, the fixing belt is pressed against the pressure member by the nip forming member and rotationally driven, and the fixing belt and the pressure member are pressed against each other. In the fixing device for fixing the toner image to the recording medium in the nip portion, it is an object of the present invention to reduce the size of the fixing device, reduce heat loss during heat fixing, and save energy.

In the fixing device according to the present invention, in order to solve the above-mentioned problems, a fixing belt wound around the heating side member and the nip forming member and the fixing belt are attached to the nip forming member. It is provided with a pressure member that is pressed and contacted so as to be sandwiched and rotationally driven, and in a state where tension is applied to the fixing belt by the pressing member, the fixing belt is pressed against the pressure member by the nip forming member and rotationally driven. In the fixing device for fixing the toner image to the recording medium at the nip portion where the fixing belt and the pressurizing member are pressure-contacted , the tension is applied to the fixing belt between the heating side member and the nip portion. The pressing member urges the heating side member away from the nip portion in the direction of inclination, and at least a part of the pressing member is located outside the region around which the fixing belt is wound. I tried to make it.

Here, like the fixing device, the heating side member is niped by the pressing member in a direction inclined with respect to the direction in which tension is applied to the fixing belt between the heating side member and the nip portion. together is urged away from the part, the Ru arrangement is to be located at least the outer part of the fixing belt is wound region of the pressing member, the pressing member is provided inside the fixing belt, the heating side member The diameter of the fixing belt can be reduced and the size of the fixing device can be reduced as compared with the case where tension is applied to the fixing belt along the line connecting the center of the fixing belt and the center of the nip portion.

Further, in the fixing device, when the nip forming member is provided by pressing the fixing belt against the pressure member as described above, the support member is opposed to the pressure member via the fixing belt. Is preferably provided in the width direction of the fixing belt, and the nip forming member is fixedly attached to the attachment surface of the support member facing the pressurizing member. In this way, when the nip forming member is fixedly attached to the mounting surface of the support member, the nip forming member is made smaller than the case where the fixing roller as shown in Patent Document 2 or the like is used for the nip forming member. However, it becomes easy to secure a sufficient nip portion, the diameter of the fixing belt can be reduced, and the fixing device can be made smaller.

Further, in the fixing device, it is preferable to provide the heating side member at a position upstream of the center position of the nip portion in the moving direction of the fixing belt. When the heating side member is provided at a position upstream of the center position of the nip portion in the moving direction of the fixing belt in this way, the length of the fixing belt at the portion heated by the heating side member and guided to the nip portion is shortened. This makes it possible to prevent the heat of the fixing belt guided between the nip forming member and the pressurizing member from decreasing, and to save energy.

Further, in the fixing device, it is preferable to provide the pressing member on the downstream side in the moving direction of the fixing belt with respect to the nip portion. In this way, when the pressing member is provided on the downstream side in the moving direction of the fixing belt from the nip portion, the heating side member is provided on the upstream side in the moving direction of the fixing belt from the center position of the nip portion as described above. The pressing member does not get in the way, and the heating side member can be appropriately arranged at a position upstream of the center position of the nip portion in the moving direction of the fixing belt.

Further, in the fixing device, when the end portions extending in the width direction of the fixing belt of the support member are attached to the side plates on both sides of the fixing device, the moving direction of the fixing belt on the mounting surface of the support member. On the upstream side and the downstream side of the above, extension portions extending in a direction intersecting the moving direction of the fixing belt toward the heating side member are provided, and the extension portion extends at the end portion of the support member. It is preferable that the length is shorter than the extension length in the extension portion other than the end portion. In this way, the support member can be arranged near the heating side member, the diameter of the fixing belt can be reduced, the fixing device can be miniaturized, and heat loss or the like during heating fixing can be reduced. Can be done.

Further, in the fixing device, when the support member and the heating side member are provided, the support members are attached to the side plates on both sides of the fixing device with the ends extending in the width direction of the fixing belt in the support member. It is possible to provide a mounting portion and a heating side member mounting portion for mounting the end portion of the heating side member.

Here, as the supporting member, it is formed in a shape of cross-section U, to the downstream side in the moving direction and the moving direction upstream side of the fixing belt in the mounting surface for mounting by fixing the nip forming member, the heating member An upstream extension portion and a downstream extension portion extending in the direction opposite to the nip portion are provided, and the length of the upstream extension portion is shorter than the length of the downstream extension portion. Can be used.

Further, in the fixing device, when the heating side member attachment portions are provided on the side plates on both sides of the fixing device and the heating side member attached to the heating side member attachment portion is urged in the direction away from the nip portion, the heating side is used. A heat insulating bush is provided on the outer periphery of the end portion of the member, and a bearing member for rotatably holding the end portion of the heating side member is provided on the heating side member mounting portion, and the heating side member is pressed by the pressing member via the bearing member. It can be urged away from the nip. When the heat insulating bush is provided on the outer periphery of the end portion of the heating side member in this way, the heat of the heating side member is prevented from being transmitted to the bearing member and released, and is heated by the pressing member via the bearing member. By urging the side member in the direction away from the nip portion, it is not necessary to provide the pressing member in the fixing belt, the diameter of the fixing belt can be reduced, and the fixing device can be miniaturized.

Further, in the fixing device, the nip forming member is made of a heat-resistant resin such as a liquid crystal polymer (LCP), and the corner portion on the upstream side in the moving direction of the fixing belt in the nip forming member around which the fixing belt is wound is formed. It is preferable to have an R shape. In this way, when the corner portion on the upstream side in the moving direction of the fixing belt in the nip forming member around which the fixing belt is wound is formed into an R shape, the resistance of the fixing belt guided from the nip forming member to the nip portion is reduced, and the fixing belt becomes It will be driven stably by rotation.

Further, in the fixing device, in the support member, a guide member for guiding the fixing belt to the heating side member is provided at a portion downstream of the support member on the downstream side in the moving direction of the fixing belt from the nip forming member. It is preferable that the corner portion of the guide member around which the fixing belt is wound has an R shape. In this way, the fixing belt is guided to the guide member from the nip forming member so as not to come into contact with the support member, and the resistance of the fixing belt moving through the guide member is reduced, so that the fixing belt becomes stable. Will be driven to rotate.

Further, in the image forming apparatus of the present invention, the fixing apparatus as described above is used as the fixing apparatus for fixing the toner image formed on the recording medium on the recording medium.

In the fixing device of the present invention, the heating side member is nipped by the pressing member in a direction inclined with respect to the direction in which tension is applied to the fixing belt between the heating side member and the nip portion as described above. together is urged away from the part, since the arrangement is allowed to be located at least the outer part of the fixing belt is wound region of the pressing member, the pressing member is provided inside the fixing belt, the heating side member Compared with the case where tension is applied to the fixing belt along the line connecting the center of the fixing belt and the center of the nip portion, the diameter of the fixing belt can be reduced and the fixing device can be made smaller. ..

As a result, in the image forming apparatus using the fixing apparatus as described above, the fixing apparatus can be miniaturized to reduce heat loss and the like at the time of heat fixing, and energy saving can be achieved.

It is the schematic explanatory drawing which showed the example of the image forming apparatus using the fixing apparatus which concerns on Embodiment 1 of this invention. It is the schematic explanatory drawing which showed the fixing apparatus which concerns on the said Embodiment 1. In the fixing device according to the first embodiment, the support member for which the nip forming member is fixedly arranged is shown, (A) is a schematic perspective view, and (B) is a schematic side view. FIG. 5 is a schematic explanatory view showing a state in which the fixing belt to be wound so as to bridge the heating roller and the nip forming member is removed in the fixing device according to the first embodiment. FIG. 5 is a schematic explanatory view showing a state in which a fixing belt is wound around a heating roller and a nip forming member so as to be bridged in the fixing device according to the first embodiment. It is the schematic explanatory drawing which showed the fixing device which concerns on Embodiment 2 of this invention.

Next, the fixing device according to the embodiment of the present invention and the image forming device using the fixing device will be specifically described with reference to the accompanying drawings. The fixing device and the image forming device according to the present invention are not limited to those shown in the following embodiments, and can be appropriately modified and implemented without changing the gist thereof.

(Embodiment 1)
FIG. 1 shows an image forming apparatus using the fixing apparatus according to the first embodiment.

Then, in this image forming apparatus 1, as shown in FIG. 1, four imaging cartridges 10A to 10D are mounted therein.

Here, in each of the imaging cartridges 10A to 10D described above, the photoconductor 11, the charging device 12 for charging the surface of the photoconductor 11, and the surface of the charged photoconductor 11 are exposed according to the image information. A latent image forming device 13 that forms an electrostatic latent image on the surface of the photoconductor 11 and a developing device 14 that supplies toner to the electrostatic latent image formed on the surface of the photoconductor 11 to form a toner image. A first cleaning device 15 is provided to remove the toner remaining after the toner image formed on the surface of the photoconductor 11 is transferred to the intermediate transfer belt 21 from the surface of the photoconductor 11.

Further, in the developing apparatus 14 of each of the imaging cartridges 10A to 10D, toners having different colors are accommodated, and black, yellow, magenta, and cyan toners are accommodated.

Then, in the image forming apparatus 1, in each of the imaging cartridges 10A to 10D, the surface of the photoconductor 11 is charged by the charging device 12, and the surface of each of the photoconductors 11 charged in this way is latent. The image forming apparatus 13 performs exposure according to the image information, forms an electrostatic latent image corresponding to the image information on the surface of each photoconductor 11, and thus electrostatically formed on the surface of each photoconductor 11. Toners of each color are supplied to the latent image from each of the developing devices 14, so that a toner image of each color is formed on the surface of each photoconductor 11.

Next, the intermediate transfer belt 21 in which the toner images of each color formed on the surface of each photoconductor 11 in each of the imaging cartridges 10A to 10D are hung on the drive roller 20a and the rotary roller 20b and driven to rotate. The toner image synthesized on the intermediate transfer belt 21 is formed by sequentially transferring the toner image onto the surface by the primary transfer roller 22, and the toner image thus formed is transferred by the intermediate transfer belt 21 to the secondary transfer roller. While guiding the toner to a position facing the 23, the toner remaining on the surface of each photoconductor 11 after transfer is removed from the surface of each photoconductor 11 by the corresponding first cleaning device 15.

On the other hand, the recording medium S housed in the image forming apparatus 1 is fed by the paper feed roller 24 and guided to the timing roller 25, and the recording medium S is guided to the timing roller 25 by the timing roller 25 at an appropriate timing. It is guided between 21 and the secondary transfer roller 23.

Then, while the toner image formed on the intermediate transfer belt 21 is transferred to the recording medium S by the secondary transfer roller 23, it remains on the intermediate transfer belt 21 without being transferred to the recording medium S. The toner is removed from the intermediate transfer belt 21 by the second cleaning device 26.

Next, the recording medium S on which the toner image is transferred is guided to the fixing device 30, and the unfixed toner image transferred to the recording medium S is fixed to the recording medium S in the fixing device 30, and then the toner. The recording medium S on which the image is fixed is separated from the fixing device 30 and guided to the paper ejection roller 27, and the recording medium S on which the toner image is fixed is ejected by the paper ejection roller 27.

Here, in the fixing device 30 according to the first embodiment, as shown in FIGS. 1 and 2, a heating roller 31 provided with a heating device 31a such as a halogen lamp inside is used as the heating side member 31. The fixing belt 33, which has been made endless by the heating roller 31, is heated.

Then, the endless fixing belt 33 is hung on the heating roller 31 and the nip forming member 32 fixedly attached to the attachment surface 35a of the support member 35 formed in a U shape. Along with winding the nip forming member 32 so as to pass it over, a pressure member 34 composed of a pressure roller 34 rotationally driven so as to sandwich the fixing belt 33 is brought into pressure contact with the fixing belt 33. With the tension applied, the fixing belt 33 is rotated together with the pressure roller 34, and the toner is formed in the nip portion where the heating fixing belt 33 is pressed against the pressure roller 34 by the nip forming member 32. The image t is fixed on the recording medium S.

Then, in the fixing device 30 of the first embodiment, the heating roller 31 is moved upstream in the moving direction of the fixing belt 33 in the nip portion from the center position of the nip portion where the fixing belt 33 is pressed against the pressure roller 34. As shown in FIG. 2 and the like, the end portion of the heating roller 31 is rotatably attached to the heating side member attachment portion 301 provided on the side plate 300 of the fixing device 30 so as to be positioned on the side portion. I have to.

Here, when the heating roller 31 is positioned on the nip portion on the upstream side in the moving direction of the fixing belt 33 from the center position of the nip portion where the fixing belt 33 is pressed against the pressure roller 34 as described above, The moving distance of the fixing belt 33 until it is heated by the heating roller 31 and guided to the nip portion is shortened, so that the heat of the fixing belt 33 can be prevented from decreasing.

Further, in this embodiment, when the end portion of the heating roller 31 is rotatably attached to the heating side member attachment portion 301 provided on the side plate 300 of the fixing device 30 as described above, the outer circumference of the end portion of the heating roller 31 is rotatably attached. In addition to arranging the heat insulating bush 31b, the heating side member mounting portion 301 is provided with a bearing member 31c made of a bearing that rotatably holds the end portion of the heating roller 31 provided with the heat insulating bush 31b.

Further, in the fixing device 30 of the first embodiment, when the heating roller 31 is urged by the pressing member 37 in a direction away from the nip portion, the tip portion of the compression coil spring 37a is used as the pressing member 37. Is provided with a mounting member 37b to be attached to the bearing member 31c, and the pressing member 37 is arranged in the pressing member mounting portion 302 provided so as to communicate with the heating side member mounting portion 301 in the side plate 300. The mounting member 37b provided at the tip of the compression coil spring 37a urges the heating roller 31 in the direction away from the nip portion via the bearing member 31c. Since the heating roller 31 is urged by the pressing member 37 in the direction away from the nip portion in this way, although not shown, the direction in which the heating side member mounting portion 301 is urged to the heating roller 31. It is formed so that the length of is long.

Further, as described above, the heating roller 31 is positioned at a portion upstream of the nip portion in the moving direction of the fixing belt 33 with respect to the center position of the nip portion where the fixing belt 33 is pressed against the pressure roller 34. When urging the heating roller 31 away from the nip portion by the pressing member 37 of the above, the center position of the nip portion and the heating roller 31 are directed from a position above the heating roller 31 toward the downstream side in the moving direction of the fixing belt 33. The heating roller 31 is pressed by the pressing member 37 in a direction that is inclined with respect to the line connecting the centers of the above and is inclined with respect to the direction in which tension is applied to the fixing belt 33 .

Further, in the fixing device 30 of the first embodiment, when the nip forming member 32 is provided on the mounting surface 35a on the side opposite to the heating roller 31 of the support member 35 formed in the U shape as described above, the nip is formed. The member 32 is made of a heat-resistant resin such as LCP (liquid crystal polymer) or PPS (polyphenylene sulfide), and the surface of the nip forming member 32 in contact with the fixing belt 33 is covered with a sliding sheet 32a. At the same time, the corner portion on the upstream side in the moving direction of the fixing belt 33 in the nip forming member 32 around which the fixing belt 33 is wound is formed into an R shape to reduce the load applied to the fixing belt 33 when the fixing belt 33 is rotationally driven. The fixing belt 33 is smoothly rotationally driven.

Further, in the fixing device 30 of the first embodiment, in the support member 35 formed in the U shape as described above, the fixing belt 33 is upstream in the moving direction on the mounting surface 35a to which the nip forming member 32 is attached. The upstream side extending portion 35b and the downstream side extending portion 35c are extended toward the heating roller 31 side in a direction intersecting the moving direction of the fixing belt 33 on the side and the downstream side in the moving direction. At the same time, the extension length xa of the upstream extension portion 35b is made shorter than the extension length xb of the downstream extension portion 35c. In this way, when the heating roller 31 is provided at a position on the nip portion on the upstream side in the moving direction of the fixing belt 33 from the center position of the nip portion as described above, the heating roller 31 extends on the upstream side. It is possible to reduce the heat loss by suppressing the heat from the heating roller 31 flowing to the support member 35 through the upstream extending portion 35b and being released without getting too close to the protruding portion 35b.

Then, in the fixing device 30 of the first embodiment, the fixing belt 33 after passing through the nip forming member 32 is guided to the heating roller 31 on the downstream extending portion 35c of the support member 35. A member 38 is provided, and the corner portion of the guide member 38 around which the fixing belt 33 is wound is formed into an R shape to reduce the load applied to the fixing belt 33 when the fixing belt 33 is rotationally driven, so that the fixing belt 33 can be smoothly operated. It is driven to rotate. As the guide member 38, similarly to the nip forming member 32, a member made of a heat-resistant resin such as LCP (liquid crystal polymer) or PPS (polyphenylene sulfide) is used.

Further, in the fixing device 30 of the first embodiment, the lubricant is held on the inner peripheral surface of the fixing belt 33, and the lubricant is appropriately held on the sliding sheet 32a of the nip forming member 32. The frictional resistance between the fixing belt 33 and the nip forming member 32 is reduced, and a lubricant regulating portion 38a is provided on the upper surface portion of the guide member 38 along the longitudinal direction thereof to lubricate the guide member 38. The agent regulating unit 38a regulates and stabilizes the amount of the lubricant adhering to the inner peripheral surface of the fixing belt 33.

Then, in the fixing device 30 of the first embodiment, the end portion of the support member 35 as described above is attached to the support member mounting portion 303 provided on the side plate 300 of the fixing device 30.

Here, in the fixing device 30 of the first embodiment, as the support member 35, as shown in FIGS. 3 (A) and 3 (B), at both end portions of the support member 35, the upstream Notches 35b1 and 35c1 are provided in the side extending portion 35b and the downstream extending portion 35c, respectively, and the length of the upstream extending portion 35b and the downstream extending portion 35c extending from the mounting surfaces 35a at both ends. Is shortened, and a recess 35a1 is provided on the mounting surface 35a.

Then, as shown in FIG. 4, at the end portions on both sides of the support member 35, the end portions of the upstream side extension portion 35b and the downstream side extension portion 35c whose length extending from the mounting surface 35a is shortened are provided. , Each of the holes 303a and 303b provided in the support member mounting portion 303 is projected from the side plate 300 of the fixing device 30, and the recess 35a1 provided in the mounting surface 35a is formed between the holes 303a and 303b. I try to pinch it.

Here, as described above, notches 35b1 and 35c1 are provided in the upstream extending portion 35b and the downstream extending portion 35c, respectively, at both end portions of the support member 35, and the upstream extending portion 35b and the downstream extending portion 35b are provided. By shortening the length of the protruding portion 35c extending from the mounting surface 35a at both end portions, the size of the holes 303a and 303b provided in the support member mounting portion 303 can be reduced.

As a result, in the side plate 300 of the fixing device 30, the distance between the heating side member mounting portion 301 for mounting the end portion of the heating roller 31 and the support member mounting portion 303 for mounting the end portion of the support member 35 can be increased. The pressing member mounting portion 302 for mounting the pressing member 37 can be provided at an appropriate position on the side plate 300 of the fixing device 30, so that the fixing device 30 can be miniaturized.

In the fixing device 30 of the first embodiment, the heating roller 31 as described above is used as the heating side member 31, but the heating side member 31 can heat the fixing belt 33. However, it is not particularly limited, and although not shown, it is also possible to use an induction heating heating element using an exciting coil.

(Embodiment 2)
In the fixing device 30B of the second embodiment, as shown in FIG. 6, as shown in Patent Document 1, the tension roller 311 and the heater unit 312 are used as the heating side member 310, while the nip forming member 320. The fixing belt 330 is wound so as to bridge the tension roller 311 and the fixing roller 320, and the tension roller 311 is wound by the pressing spring (pressing member) 370. Tension is applied to the fixing belt 330 by urging the fixing roller 320 in a direction away from the fixing roller 320 via the holding member 360.

Here, in the second embodiment, a holding member 360 that is rotated around a fulcrum 361 on one end side is provided outside the fixing belt 330, and the holding member 360 holds the tension roller 311. On the other hand, one end of the pressing spring 370 provided on the fixing roller 320 side is attached to the other end side of the holding member 360, and the tension roller 311 is transferred from the fixing roller 320 via the holding member 360 by the pressing spring 370. The tension is applied to the fixing belt 330 by urging the fixing belt 330 in the direction of separation.

Further, in the second embodiment, on the way from the tension roller 311 to the fixing roller 320, the heater unit 312 is brought into contact with the inner peripheral surface of the fixing belt 330, and the fixing belt 330 is heated by the heater unit 312. I try to let you.

Then, in the second embodiment, the pressurizing member 340 composed of the pressurizing roller 340 that is rotationally driven by sandwiching the fixing belt 330 with the fixing roller 320 at a position facing the fixing roller 320. The toner image t is recorded in the nip portion where the fixing belt 330 is pressed together with the pressure roller 340 and the fixing belt 330 heated as described above is pressed against the pressure roller 340 by the fixing roller 320. It is fixed on the medium S.

Here, in the fixing device 30B of the second embodiment, the holding member 360 provided outside the fixing belt 330 is pressed by the pressing spring 370 provided on the fixing roller 320 side as described above, and the tension roller is used. Since the 311 is urged away from the fixing roller 320, the fixing device 300 can be made smaller than that of Patent Document 1 in which a tension spring is used as the tension applying member. Become.

1 Image forming device 10A to 10D Imaging cartridge 11 Photoreceptor 12 Charging device 13 Latent image forming device 14 Developing device 15 First cleaning device 20a Drive roller 20b Rotating roller 21 Intermediate transfer belt 22 Primary transfer roller 23 Secondary transfer roller 24 Paper feed Roller 25 Timing roller 26 Second cleaning device 27 Paper ejection roller 30, 30B Fixing device 31 Heating roller (heating side member)
31a Heating device 31b Insulation bush 31c Bearing member 32 Nip forming member 32a Sliding sheet 33 Fixing belt 34 Pressurizing roller (pressurizing member)
35 Support member 35a Mounting surface 35a1 Recess 35b Upstream extension 35b1 Notch 35c Downstream extension 35c1 Notch 37 Pressing member 37a Compression coil spring 37b Mounting member 38 Guide member 38a Lubricant regulation part 300 Side plate 301 Heating side member Mounting part 302 Pressing member mounting part 303 Supporting member mounting part 303a, 303b Hole 310 Heating side member 311 Tension roller 312 Heater unit 320 Fixing roller (nip forming member)
330 Fixing belt 340 Pressurizing roller (pressurizing member)
360 Holding member 361 Supporting point 370 Pressing spring (pressing member)
S Recording medium t Toner image

Claims (11)

A pressing member is provided with a fixing belt that is wound so as to bridge the heating side member and the nip forming member, and a pressure member that is rotationally driven by pressure contacting the nip forming member so as to sandwich the fixing belt. In a state where tension is applied to the fixing belt, the fixing belt is pressed against the pressure member by the nip forming member and rotationally driven, and a toner image is displayed at the nip portion where the fixing belt and the pressure member are pressure-contacted. In the fixing device for fixing to the recording medium, the heating side member is fixed to the nip portion by the pressing member in a direction inclined with respect to the direction in which tension is applied to the fixing belt between the heating side member and the nip portion. A fixing device characterized in that at least a part of the pressing member is arranged so as to be located outside the region around which the fixing belt is wound , while urging the pressing member in a direction away from the above. In the fixing device according to claim 1, a support member is provided in the width direction of the fixing belt so as to face the pressure member via the fixing belt, and the mounting surface of the support member facing the pressure member is provided. A fixing device characterized in that the nip forming member is fixedly attached. The fixing device according to claim 2, wherein the heating side member is provided at a position upstream of the center position of the nip portion in the moving direction of the fixing belt. The fixing device according to claim 2 or 3, wherein the pressing member is provided on the downstream side in the moving direction of the fixing belt with respect to the nip portion. In the fixing device according to any one of claims 2 to 4, the support member is attached to the side plates on both sides of the fixing device when the end portions of the support member extending in the width direction of the fixing belt are attached. An extension portion extending in a direction intersecting the movement direction of the fixing belt toward the heating side member is provided on the upstream side and the downstream side in the moving direction of the fixing belt on the mounting surface of the support member. A fixing device characterized in that the extension length of the extension portion in the above is shorter than the extension length of the extension portion other than the end portion. In the fixing device according to any one of claims 2 to 5, a support member mounting portion for mounting end portions of the support member extending in the width direction of the fixing belt on side plates on both sides of the fixing device. , A fixing device characterized in that a heating side member mounting portion for mounting an end portion of the heating side member is provided. In the fixing device according to claim 6 , a heat insulating bush is provided on the outer periphery of the end portion of the heating side member, and a bearing member for rotatably holding the end portion of the heating side member is provided on the heating side member mounting portion. A fixing device characterized in that the heating side member is urged in a direction away from the nip portion by a pressing member via the bearing member. In the fixing device according to any one of claims 2 to 7 , the support member is formed in a U- shaped cross section, and the fixing belt is upstream in the moving direction on the mounting surface on which the nip forming member is fixed and attached. On the side and the downstream side in the moving direction, an upstream side extending portion and a downstream extending portion extending in the direction opposite to the nip portion toward the heating side member are provided, and the length of the upstream side extending portion is provided. A fixing device characterized in that the length is shorter than the length of the downstream extension portion. In the fixing device according to any one of claims 2 to 8, the nip forming member is made of heat-resistant resin, and the corner portion of the nip forming member around which the fixing belt is wound is R-shaped. A fixing device characterized by. In the fixing device according to any one of claims 2 to 9, a guide member for guiding the fixing belt to the heating side member is provided at a portion of the support member on the downstream side in the moving direction of the fixing belt from the nip forming member. , A fixing device characterized in that the corners of the guide member around which the fixing belt is wound are R-shaped. An image characterized in that the fixing device according to any one of claims 1 to 10 is used in an image forming device provided with a fixing device for fixing a toner image formed on a recording medium on a recording medium. Forming device.

Images