JP7032706B2 - 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, or a composite machine thereof, and a fixing device installed therein.

Conventionally, in an image forming apparatus such as a copying machine or a printer, a fixing apparatus has been known in which a warm-up time and a first print time are short and fixing defects are unlikely to occur even when the apparatus is speeded up (for example). See Patent Document 1).

Specifically, the fixing device described in FIGS. 2 and 4 of Patent Document 1 has a pipe shape fixed so as to face the inner peripheral surface of the fixing belt except for the fixing belt (reference numeral 21) and the nip portion. To form a nip portion by pressure contacting a heating member (reference numeral 22), a heater (reference numeral 25) internally provided in the heating member for heating the heating member, and a pressure roller (reference numeral 31) via a fixing belt. It is composed of a fixing member (reference numeral 26) installed inside the fixing belt, a substantially plate-shaped reinforcing member (reference numeral 23) that abuts on the fixing member to reinforce the fixing member, and the like. The substantially plate-shaped reinforcing member is formed to have a relatively narrow width (length in the transport direction) so as to abut on a part of the surface of the fixing member.
Then, the fixing belt is heated by the pipe-shaped heating member heated by the heater, and the toner image on the recording medium conveyed toward the nip portion receives heat and pressure at the nip portion and is placed on the recording medium. It will be fixed.

Since the fixing device of Patent Document 1 described above is installed so that the fixing member is fitted into the recess of the pipe-shaped heating member, the contact area (contact width) of the reinforcing member in contact with the fixing member is narrow. Even if the balance of the force received by the fixing member from the reinforcing member becomes unbalanced, the fixing member does not fall down.

On the other hand, in the fixing device such as Patent Document 1, the pipe-shaped heating member is removed and the pipe-shaped heating member is interposed for the purpose of further improving the heating efficiency of the fixing belt and reducing the cost and size of the device. It is conceivable to adopt a configuration in which the fixing belt is directly heated by the heating means.
However, in that case, since there is no heating member (recess) that prevents the fixing member from falling, it is not possible to hold the fixing member in a state where the reinforcing member is in pressure contact in a well-balanced manner, and the fixing member may fall. There is. If the fixing member is tilted in this way, a desired nip cannot be formed, resulting in poor fixing of the output image or poor transport of the recording medium.

The present invention has been made to solve the above-mentioned problems, and the warm-up time and the first print time are short, and even when the speed of the apparatus is increased, the reinforcing member does not have a fixing defect or the like. It is an object of the present invention to provide a fixing device and an image forming device in which a fixing member in a state of being pressed against each other does not fall down.

The fixing device according to the invention according to claim 1 of the present invention is arranged on a flexible endless fixing belt and the inner peripheral surface side of the fixing belt, and is a pressurized rotating body via the fixing belt. A fixing member forming a nip portion to which a recording medium is conveyed by pressure contact with the fixing belt, a heater directly facing at least a part of the fixing belt other than the nip portion to heat the fixing belt, and the fixing belt. A reinforcing member arranged between the fixing member and the heater on the inner peripheral surface side and abutting on the fixing member, and a guide member for guiding the fixing belt at both ends in the width direction of the fixing belt are provided. The reinforcing member is non-contact with the fixing belt when the fixing belt is rotated, and the fixing member has a protrusion having a width protruding toward the facing surface of the reinforcing member so as to be in contact with the reinforcing member. A plurality of rows are provided along the directions orthogonal to the direction and come into contact with the fixing belt through the contact portion of the sheet-shaped member, and the sheet-shaped member has a plurality of holes fitted to the protruding portion in contact with the fixing belt. It is formed on the upstream side and the downstream side of the portion, respectively, and is provided so as to cover the fixing member.
The upstream side and the downstream side of the sheet-shaped member overlapped between the protrusions of the plurality of rows on the side opposite to the side where the fixing belt of the fixing member and the sheet-shaped member contact . A polymerized portion is formed, and the polymerized portion has a through-hole portion penetrating from one surface of the polymerized portion to the other surface, and is fixed to the fixing member.

In the present application, the state in which the fixing member or the reinforcing member is "fixed" is defined as a state in which the fixing member or the reinforcing member is held in a non-rotating manner without being rotationally driven. Therefore, for example, even when the fixing member is urged toward the nip portion by an urging means such as a spring, if the fixing member is held in a non-rotating manner, the fixing member is "fixed". It becomes a state.

Further, in the present application, the "conveying direction" of the recording medium is the same direction as the tangential direction of the nip portion when the fixing belt or the pressurized rotating body is brought into contact with each other in an ideal arc without deformation at the nip portion. Is defined as.
Further, in the present application, the "width direction" is defined as a direction orthogonal to the transport direction and the same direction as the rotation axis direction of the fixing belt or the pressurized rotating body.

In the present invention, the fixing member is formed with a plurality of rows of protrusions protruding toward the reinforcing member so as to be in contact with the reinforcing member along the transport direction. As a result, the warm-up time and the first print time are short, and even when the speed of the device is increased, fixing failure does not occur, and the fixing member in the state where the reinforcing member is in pressure contact does not fall down. An apparatus and an image forming apparatus can be provided.

It is an overall block diagram which shows the image forming apparatus in Embodiment 1 of this invention. It is a block diagram which shows the fixing device. It is a side view which looked at the fixing device in the width direction. It is an enlarged view which shows the neighborhood of a nip part. It is sectional drawing side view which shows the state which the fixing belt is held by the holding member. It is a schematic front view which shows the state which the fixing belt and the reinforcing member are held by the holding member. (A) side view and (B) bottom view showing a fixing member in a state where the sheet-shaped member is covered. 7 (A), (A) a schematic cross-sectional view showing an X1-X1 cross section, (B) a schematic cross-sectional view showing an X2-X2 cross section, and (C) a schematic cross-sectional view showing an X3-X3 cross section. be. (A) side view and (B) bottom view showing a fixing member. It is a developed view which shows the sheet-like member. It is a top view which shows the plate-shaped member. It is a block diagram which shows the fixing apparatus in Embodiment 2 of this invention.

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. In each figure, the same or corresponding parts are designated by the same reference numerals, and the duplicated description thereof will be appropriately simplified or omitted.

Embodiment 1.
The first embodiment of the present invention will be described in detail with reference to FIGS. 1 to 11.
First, FIG. 1 describes the configuration and operation of the entire image forming apparatus.
As shown in FIG. 1, the image forming apparatus 1 in the first embodiment is a tandem color printer. Four toner bottles 102Y, 102M, 102C, 102K corresponding to each color (yellow, magenta, cyan, black) are detachably installed (replaceable) in the bottle accommodating portion 101 above the image forming apparatus main body 1. ing.
An intermediate transfer unit 85 is arranged below the bottle accommodating portion 101. Image forming portions 4Y, 4M, 4C, and 4K corresponding to each color (yellow, magenta, cyan, and black) are arranged side by side so as to face the intermediate transfer belt 78 of the intermediate transfer unit 85.

Photoreceptor drums 5Y, 5M, 5C, and 5K are arranged in each image forming unit 4Y, 4M, 4C, and 4K, respectively. Further, around each of the photoconductor drums 5Y, 5M, 5C, and 5K, a charging unit 75, a developing unit 76, a cleaning unit 77, a static elimination unit (not shown), and the like are arranged, respectively. Then, an image forming process (charging step, exposure step, developing step, transfer step, cleaning step) is performed on each photoconductor drum 5Y, 5M, 5C, 5K, and each photoconductor drum 5Y, 5M, 5C, Images of each color will be formed on 5K.

The photoconductor drums 5Y, 5M, 5C, and 5K are rotationally driven clockwise in FIG. 1 by a drive motor (not shown). Then, the surface of the photoconductor drums 5Y, 5M, 5C, and 5K is uniformly charged at the position of the charging portion 75 (the charging step).
After that, the surfaces of the photoconductor drums 5Y, 5M, 5C, and 5K reach the irradiation position of the laser beam L emitted from the exposure unit 3, and an electrostatic latent image corresponding to each color is formed by exposure scanning at this position. (It is an exposure process).

After that, the surface of the photoconductor drums 5Y, 5M, 5C, and 5K reaches a position facing the developing device 76, and the electrostatic latent image is developed at this position to form a toner image of each color (development step). It is.).
After that, the surfaces of the photoconductor drums 5Y, 5M, 5C, and 5K reach the positions facing the intermediate transfer belt 78 and the first transfer bias rollers 79Y, 79M, 79C, and 79K, and the photoconductor drums 5Y, 5M at this position. The toner images on 5, 5C and 5K are transferred onto the intermediate transfer belt 78 (the primary transfer step). At this time, a small amount of untransferred toner remains on the photoconductor drums 5Y, 5M, 5C, and 5K.

After that, the surface of the photoconductor drum 5Y, 5M, 5C, and 5K reaches a position facing the cleaning unit 77, and the untransferred toner remaining on the photoconductor drum 5Y, 5M, 5C, and 5K at this position reaches the cleaning unit. It is mechanically recovered by 77 cleaning blades (cleaning step).
Finally, the surface of the photoconductor drum 5Y, 5M, 5C, 5K reaches a position facing the static elimination portion (not shown), and the residual potential on the photoconductor drum 5Y, 5M, 5C, 5K is removed at this position. To.
In this way, a series of image forming processes performed on the photoconductor drums 5Y, 5M, 5C, and 5K are completed.

After that, the toner images of each color formed on each photoconductor drum through the development step are superimposed and transferred on the intermediate transfer belt 78. In this way, a color image is formed on the intermediate transfer belt 78.
Here, the intermediate transfer unit 85 includes an intermediate transfer belt 78, four primary transfer bias rollers 79Y, 79M, 79C, 79K, a secondary transfer backup roller 82, a cleaning backup roller 83, a tension roller 84, and an intermediate transfer cleaning unit 80. , Etc. The intermediate transfer belt 78 is stretched and supported by three rollers 82 to 84, and is endlessly moved in the arrow direction in FIG. 1 by the rotational drive of one roller 82.

The four primary transfer bias rollers 79Y, 79M, 79C, and 79K each sandwich the intermediate transfer belt 78 between the photoconductor drums 5Y, 5M, 5C, and 5K to form a primary transfer nip. Then, a transfer bias opposite to the polarity of the toner is applied to the primary transfer bias rollers 79Y, 79M, 79C, 79K.
Then, the intermediate transfer belt 78 travels in the direction of the arrow and sequentially passes through the primary transfer nips of the primary transfer bias rollers 79Y, 79M, 79C, and 79K, respectively. In this way, the toner images of each color on the photoconductor drums 5Y, 5M, 5C, and 5K are superimposed on the intermediate transfer belt 78 and primary transfer is performed.

After that, the intermediate transfer belt 78 on which the toner images of each color are superimposed and transferred reaches the position facing the secondary transfer roller 89. At this position, the secondary transfer backup roller 82 sandwiches the intermediate transfer belt 78 with the secondary transfer roller 89 to form a secondary transfer nip. Then, the four-color toner images formed on the intermediate transfer belt 78 are transferred onto the recording medium P conveyed to the position of the secondary transfer nip. At this time, untransferred toner that has not been transferred to the recording medium P remains on the intermediate transfer belt 78.
After that, the intermediate transfer belt 78 reaches the position of the intermediate transfer cleaning unit 80. Then, at this position, the untransferred toner on the intermediate transfer belt 78 is collected.
In this way, a series of transfer processes performed on the intermediate transfer belt 78 is completed.

Here, the recording medium P conveyed to the position of the secondary transfer nip has a paper feed roller 97, a resist roller pair 98 (timing roller pair), and the like from the paper feed unit 12 arranged below the apparatus main body 1. It was transported via.
Specifically, a plurality of recording media P such as transfer paper are stacked and stored in the paper feed unit 12. Then, when the paper feed roller 97 is rotationally driven in the counterclockwise direction in FIG. 1, the top recording medium P is fed between the rollers of the resist roller vs. 98.

The recording medium P conveyed to the resist roller pair 98 is temporarily stopped at the position of the roller nip of the resist roller pair 98 where the rotation drive is stopped. Then, the resist roller pair 98 is rotationally driven in time with the color image on the intermediate transfer belt 78, and the recording medium P is conveyed toward the secondary transfer nip. In this way, the desired color image is transferred onto the recording medium P.

After that, the recording medium P on which the color image is transferred at the position of the secondary transfer nip is conveyed to the position of the fixing portion 20. Then, at this position, the color image transferred to the surface is fixed on the recording medium P by the heat and pressure of the fixing belt 21 and the pressure roller 31.
After that, the recording medium P is discharged to the outside of the device through the space between the paper ejection rollers and the rollers 99. The recording medium P discharged to the outside of the device by the paper ejection roller pair 99 is sequentially stacked on the stack unit 100 as an output image.
In this way, a series of image forming processes in the image forming apparatus is completed.

Next, FIGS. 2 to 11 will describe in detail the configuration and operation of the fixing device 20 installed in the image forming apparatus main body 1.
With reference to FIGS. 2 to 4, the fixing device 20 includes a fixing belt 21 (belt member) as a fixing member, a fixing member 26 (nip portion forming member), a reinforcing member 23, and a heater 25 (heat source) as a heating means. ), A pressure roller 31 as a pressure rotating body, a temperature sensor 40, a sheet-like member 22, a screw 24, a plate-like member 28 (fixing plate), a reflection member 27, and the like.

Here, the fixing belt 21 is a thin-walled and flexible endless belt, and rotates (runs) in the arrow direction (counterclockwise direction) in FIG. In the fixing belt 21, the base material layer, the elastic layer, and the release layer are sequentially laminated from the inner peripheral surface 21a (the sliding contact surface with the fixing member 26) side, and the total thickness thereof is 1 mm or less. Is set to.
The base material layer of the fixing belt 21 has a layer thickness of 30 to 50 μm and is made of a metal material such as nickel or stainless steel or a resin material such as polyimide.
The elastic layer of the fixing belt 21 has a layer thickness of 100 to 300 μm and is made of a rubber material such as silicone rubber, foamable silicone rubber, and fluororubber. By providing the elastic layer, minute irregularities on the surface of the fixing belt 21 at the nip portion are not formed, heat is uniformly transferred to the toner image T on the recording medium P, and the generation of a yuzu skin image is suppressed.
The release layer of the fixing belt 21 has a layer thickness of 10 to 50 μm, and has PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer), PTFE (polytetrafluoroethylene), polyimide, polyetherimide, and PES (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer). Polyethersulfide), etc. are made of materials. By providing the release layer, the release property (removability) with respect to the toner T (toner image) is ensured.

Further, the diameter of the fixing belt 21 is set to be 15 to 120 mm. In the first embodiment, the inner diameter of the fixing belt 21 is set to 30 mm.
Inside the fixing belt 21 (inner peripheral surface side), a fixing member 26, a heater (heating means), a reinforcing member 23, a reflection member 27, a sheet-shaped member 22, a screw 24, a plate-shaped member 28 (fixing plate), etc. Is fixed.
Here, the fixing member 26 is fixed so as to be in sliding contact with the inner peripheral surface 21a of the fixing belt 21. Then, the fixing member 26 is in pressure contact with the pressure roller 31 via the fixing belt 21, so that a nip portion through which the recording medium P is conveyed is formed. With reference to FIGS. 3 and 5, the fixing member 26 is held at both ends in the width direction by a flange 29 (holding member) fixedly supported by the side plate 43 of the fixing device 20. Further, both ends of the fixing belt 21 in the width direction are rotatably held by the flange 29. The configuration of the fixing member 26 and the flange 29 will be described in more detail later.
Then, the fixing belt 21 is directly heated by the radiant heat of the heater 25 (heating means) installed inside the fixing belt 21.

The heater 25 as a heating means is a halogen heater (or a carbon heater), and both ends thereof are fixed to the side plate 43 of the fixing device 20 (see FIG. 3). Then, the portion of the fixing belt 21 excluding the nip portion is heated by the radiant heat of the heater 25 (heating means) whose output is controlled by the power supply unit of the apparatus main body 1. Further, heat is applied to the toner image T on the recording medium P from the surface of the heated fixing belt 21. The output control of the heater 25 is performed based on the detection result of the belt surface temperature by the temperature sensor 40 such as a thermistor facing the surface of the fixing belt 21. Further, by controlling the output of the heater 25 in this way, the temperature of the fixing belt 21 (fixing temperature) can be set to a desired temperature.
In the first embodiment, one heater 25 is installed on the inner peripheral surface side of the fixing belt 21, but a plurality of heaters can be installed on the inner peripheral surface side of the fixing belt 21.

As described above, in the fixing device 20 according to the first embodiment, not only a part of the fixing belt 21 is locally heated, but the fixing belt 21 is heated over a relatively wide range in the circumferential direction. Therefore, even when the speed of the apparatus is increased, the fixing belt 21 is sufficiently heated and the occurrence of fixing failure can be suppressed. That is, since the fixing belt 21 can be efficiently heated with a relatively simple configuration, the warm-up time and the first print time are shortened, and the size of the device is reduced.
In particular, since the fixing device 20 in the first embodiment is configured such that the fixing belt 21 is directly heated by the heater 25 (heating means), the heating efficiency of the fixing belt 21 is further improved and the fixing belt 21 is further improved. The fixing device 21 can be further reduced in cost and size.

Here, referring to FIGS. 5 and 6, the two flanges 29 as the holding members are made of a heat-resistant resin material or the like, and are fitted into the side plates 43 at both ends in the width direction of the fixing device 20, respectively. There is. The flange 29 has a guide portion 29a for holding the fixing belt 21 while maintaining the circular posture of the fixing belt 21, a stopper portion 29b for restricting the movement of the fixing belt 21 in the width direction (close to the belt), and the like. Is provided.
Further, on the inner peripheral surface 21a of the fixing belt 21, sliding portions (enclosed by broken lines in FIG. 5) with the guide portions 29a of the flange 29 at both ends in the width direction (the left-right direction in FIG. 5). A low friction portion 21a1 is formed to reduce the sliding resistance in the portion). Specifically, the low friction portion 21a1 is formed by coating the surface of the base material layer with a low friction material such as fluororesin. With such a configuration, even if the fixing belt 21 and the flange 29 (guide portion 29a) are in sliding contact with each other due to the rotation (running) of the fixing belt 21, the fixing belt 21 and the flange 29 (guide portion 29a) are less likely to be worn and deteriorated. ..
In the first embodiment, the members that come into contact with the inner peripheral surface 21a of the fixing belt 21 are only the flanges 29 at both ends in the width direction and the fixing member 26, and other than that, they come into contact with the inner peripheral surface 21a. Therefore, there is no member (belt guide) that guides the rotation of the fixing belt 21.

Here, in the first embodiment, the reinforcing member 23 for reinforcing the strength of the fixing member 26 forming the nip portion is fixed to the inner peripheral surface side of the fixing belt 21. With reference to FIG. 3, the reinforcing member 23 is formed so that the length in the width direction is equal to that of the fixing member 26, and both ends in the width direction are held by the flange 29 (holding member) of the fixing device 20. Has been done. Specifically, the position of the reinforcing member 23 is determined so as to be sandwiched between the flange 29 and the fixing member 26. In the first embodiment, as shown in FIG. 6, the end faces (reference planes 23b) of the two upright portions 23c of the reinforcing member 23 (the portions that stand up in a direction away from the facing surface 23a). Is configured to abut on the holding portion 29c of the flange 29 (see FIG. 6) to hold the reinforcing member 23. On the other hand, the reinforcing member 23 may be held in contact with the side plate 43 instead of the holding portion 29c of the flange 29.
Then, the reinforcing member 23 comes into contact with the pressure roller 31 via the fixing member 26 and the fixing belt 21, thereby suppressing a problem that the fixing member 26 is greatly deformed by the pressure of the pressure roller 31 at the nip portion. ing. In the first embodiment, the reinforcing member 23 is a substantially U-shaped plate-shaped member formed so that the recesses face each other on the side where the heater 25 is located. The reinforcing member 23 is preferably formed of a metal material having high mechanical strength such as stainless steel or iron in order to satisfy the above-mentioned functions.
The configuration of the reinforcing member 23 will be described in more detail later.

Further, in the first embodiment, the reflective member 27 (reflector) is fixedly provided on the side of the reinforcing member 23 on the side facing the heater 25. As a result, the heat from the heater 25 toward the reinforcing member 23 (heat that heats the reinforcing member 23) is reflected by the reflective member 27 and used for heating the fixing belt 21, so that the heating efficiency of the fixing belt 21 is improved. It will be further improved.
It should be noted that the same effect can be obtained even when a mirror surface treatment or a heat insulating member is provided on a part or all of the surface of the reinforcing member 23 facing the heater 25.

With reference to FIG. 2, the pressure roller 31 as a pressure rotating body that abuts on the outer peripheral surface of the fixing belt 21 at the position of the nip portion has a diameter of 30 mm and has an elastic layer on the core metal 32 having a hollow structure. 33 is formed. The elastic layer 33 of the pressure roller 31 (pressurized rotating body) is made of a material such as foamable silicone rubber, silicone rubber, or fluorine rubber. A thin mold release layer made of PFA, PTFE, or the like can be provided on the surface layer of the elastic layer 33. The pressure roller 31 is pressed against the fixing belt 21 to form a desired nip portion between both members. Further, referring to FIG. 3, the pressurizing roller 31 is provided with a gear 45 that meshes with a drive gear of a drive mechanism (not shown), and the pressurizing roller 31 is directed in the arrow direction (clockwise direction) in FIG. It is driven to rotate. Further, both ends of the pressure roller 31 in the width direction are rotatably supported by the side plate 43 of the fixing device 20 via a bearing 42. A heat source such as a halogen heater may be provided inside the pressurizing roller 31.

When the elastic layer 33 of the pressure roller 31 is made of a sponge-like material such as foamable silicone rubber, the pressing force acting on the nip portion can be reduced, so that the load generated on the fixing member 16 is applied. Can be mitigated. Further, the heat insulating property of the pressure roller 31 is enhanced, and the heat of the fixing belt 21 is less likely to move to the pressure roller 31 side, so that the heating efficiency of the fixing belt 21 is improved.
Further, in the first embodiment, the diameter of the fixing belt 21 is formed to be substantially the same as the diameter of the pressure roller 31, but the diameter of the fixing belt 21 is smaller than the diameter of the pressure roller 31. It can also be formed. In that case, since the curvature of the fixing belt 21 in the nip portion is smaller than the curvature of the pressurizing roller 31, the recording medium P transmitted from the nip portion is easily separated from the fixing belt 21.

With reference to FIG. 4, the fixing member 26 which is in sliding contact with the inner peripheral surface 21a of the fixing belt 21 has a concave shape so that the facing surface (sliding contact surface) with the pressure roller 31 follows the curvature of the pressure roller 31. Is formed in. As a result, the recording medium P is sent out from the nip portion so as to follow the curvature of the pressure roller 31, so that the problem that the recording medium P after the fixing step is attracted to the fixing belt 21 and does not separate is suppressed. be able to.
In the first embodiment, the shape of the fixing member 26 forming the nip portion is formed in a concave shape, but the shape of the fixing member 26 forming the nip portion can also be formed in a planar shape. That is, the sliding contact surface of the fixing member 26 (the surface facing the pressure roller 31) can be formed so as to have a planar shape. As a result, the shape of the nip portion becomes substantially parallel to the image plane of the recording medium P, and the adhesion between the fixing belt 21 and the recording medium P is improved, so that the fixing property is improved. Further, since the curvature of the fixing belt 21 on the outlet side of the nip portion becomes large, the recording medium P sent out from the nip portion can be easily separated from the fixing belt 21.

Further, as the material for forming the fixing member 26, a resin material or a metal material can be used, but the material has rigidity to such an extent that it does not bend significantly even when pressed by the pressure roller 31, and has heat resistance. A resin material having heat insulating properties (such as liquid crystal polymer and polyamide-imide) is suitable. In the first embodiment, a liquid crystal polymer (LCP) is used as the material of the fixing member 26.

Further, the fixing member 26 is covered with a sheet-like member 22 made of a low friction material such as PTFE in order to reduce the sliding resistance with the fixing belt 21. Specifically, the sheet-shaped member 22 is fixed around the fixing member 26 (fixed in a cross section as shown in FIG. 4) so as to be interposed between the fixing member 26 and the fixing belt 21 in the width direction at the position of the nip portion. It is installed so as to cover the circumference of the member 26). Further, the sheet-shaped member 22 in the first embodiment is formed of a fiber material (a cloth member made of PTFE) impregnated with a lubricant such as silicone oil. As a result, the lubricant is held on the surface where the fixing member 26 and the fixing belt 21 come into contact with each other. Therefore, the problem that both members 21 and 26 are worn by the sliding contact between the fixing member 26 and the fixing belt 21 is reduced.
The configuration of the sheet-shaped member 22 and the fixing member 26 will be described in more detail later.

Here, in the first embodiment, the reinforcing member 23 (and the reflecting member 27) are installed so as to isolate the space between the fixing member 26 and the heater 25 (heating means).
In the first embodiment, since the heater 25 is installed so as to face a relatively wide range in the circumferential direction of the fixing belt 21 (inner peripheral surface 21a), the fixing belt 21 (inner peripheral surface 21a) is fixed even during heating standby (printing operation standby). The belt 21 can be heated evenly in the circumferential direction. Therefore, after receiving the print request, the print operation can be performed immediately. At this time, in the conventional on-demand fixing device (see, for example, Japanese Patent No. 2884714), when heat is applied to the nip portion while the pressurizing roller is deformed during standby for heating, the rubber of the pressurizing roller is applied. Depending on the material of, the life of the pressurizing roller may be shortened due to thermal deterioration, or compression set may occur in the pressurizing roller (compression set of rubber is heated by the deformation of rubber. It increases by adding.). When compression set is generated in the pressure roller, a part of the pressure roller becomes dented and the desired nip width cannot be obtained, so that fixing failure occurs or abnormal noise occurs during rotation. do.
On the other hand, in the first embodiment, since the reinforcing member 23 (and the reflecting member 27) is installed between the fixing member 26 and the heater 25 so as to block the heat of the heater 25, the heating is performed. It becomes difficult for heat to reach the fixing member 26 during standby. Therefore, it is possible to reduce the problem that the pressure roller 31 is heated at a high temperature in a deformed state during the heating standby, and to prevent the above-mentioned problem from occurring.

Further, the lubricant applied between both members in order to reduce the frictional resistance between the fixing member 26 and the fixing belt 21 deteriorates due to use under high temperature conditions in addition to high pressure conditions at the nip portion, and the fixing belt 21 There is a possibility that problems such as slipping will occur.
On the other hand, in the first embodiment, since the reinforcing member 23 (and the reflecting member 27) is installed between the fixing member 26 and the heater 25 so as to block the heat of the heater 25, the heater It becomes difficult for the heat of 25 to reach the lubricant of the nip portion. Therefore, deterioration of the lubricant due to high temperature is reduced, and it is possible to prevent the above-mentioned problems from occurring.

Further, in the first embodiment, since the reinforcing member 23 (and the reflecting member 27) is installed between the fixing member 26 and the heater 25 so as to block the heat of the heater 25, the fixing member 26 is provided. It is insulated and the fixing belt 21 is not positively heated at the nip portion. Therefore, the temperature of the recording medium P sent into the nip portion becomes low when it is sent out from the nip portion. That is, at the outlet of the nip portion, the temperature of the toner image fixed on the recording medium P is lowered, the viscosity of the toner is lowered, and the toner adhesive force with respect to the fixing belt 21 is reduced. It is separated from the fixing belt 21. Therefore, the problem that the recording medium P immediately after the fixing step is wound around the fixing belt 21 and becomes jam is prevented, and the toner sticking to the fixing belt 21 is also suppressed.

Hereinafter, the normal operation of the fixing device 20 configured as described above will be briefly described.
When the power switch of the apparatus main body 1 is turned on, electric power is supplied to the heater 25 and the rotary drive of the pressurizing roller 31 in the direction of the arrow in FIG. 2 is started. As a result, the fixing belt 21 also moves (rotates) in the direction of the arrow in FIG. 2 due to the frictional force with the pressure roller 31 in the nip portion.
After that, the recording medium P is fed from the paper feed unit 12, and the unfixed color image is supported (transferred) on the recording medium P at the position of the secondary transfer roller 89. The recording medium P on which the unfixed image T (toner image) is supported is conveyed in the direction of arrow Y10 in FIG. 2 while being guided by a guide plate (not shown), and the fixing belt 21 and the pressure roller 31 in a pressure-welded state. It is sent to the nip part.
Then, the toner image T is fixed on the surface of the recording medium P by the heating by the fixing belt 21 heated by the heater 25 and the pressing force between the fixing member 26 reinforced by the reinforcing member 23 and the pressure roller 31. .. After that, the recording medium P transmitted from the nip portion is conveyed in the direction of arrow Y11.

Hereinafter, the characteristic configuration / operation of the fixing device 20 according to the first embodiment will be described in detail.
As described above, in the fixing device 20 according to the first embodiment, the fixing device 20 is fixedly attached to the inner peripheral surface side of the fixing belt 21 and is pressed against the pressure roller 31 via the fixing belt 21 to form a nip portion. A fixing member 26 is installed, and a reinforcing member 23 which is fixedly fixed to the inner peripheral surface side of the fixing belt 21 and abuts on the fixing member 26 from the inside of the fixing belt 21 to reinforce the fixing member 26.
Here, in the first embodiment, as shown in FIG. 4, the fixing members 26 have the protruding portions 26a and 26b protruding toward the facing surface 23a of the reinforcing member 23 so as to be in contact with the reinforcing member 23. A plurality of rows are provided along the transport direction of the medium P (or the rotation direction of the fixing belt 21). Specifically, as a plurality of rows of projecting portions, an upstream projecting portion 26a projecting toward the facing surface 23a of the reinforcing member 23 so as to abut on the reinforcing member 23 on the upstream side in the transport direction of the recording medium P, and a recording medium. A downstream side projecting portion 26b that projects toward the facing surface 23a of the reinforcing member 23 is formed so as to abut on the reinforcing member 23 on the downstream side with respect to the transport direction of P. That is, the fixing member 26 is set to B in two rows of protruding portions 26a and 26b (the distance between the upstream side end portion and the downstream side end portion) separated in the transport direction on the side facing the reinforcing member 23. ) Is provided, and these two rows of protruding portions 26a and 26b come into surface contact with the facing surfaces 23a of the reinforcing member 23, respectively.

With such a configuration, even when a pipe-shaped heating member for fitting and fixing the fixing member 26 is not installed, the fixing member 26 in a state where the reinforcing member 23 is in pressure contact is held in a well-balanced manner, so that the fixing member The problem that the 26 falls down is suppressed. Then, the desired nip is formed with high accuracy, and it is possible to prevent a defect such as a fixing defect in the output image or a transport defect in the recording medium.
That is, when the fixing member 26 abuts on the reinforcing member 23 in a biased manner toward the upstream side in the transport direction or the downstream side in the transport direction, or when the contact width (distance B) of the fixing member 26 abutting on the reinforcing member 23 is narrow. The fixing member 26 that has received the pressure contact force at the nip portion tends to rotate (prone to fall) in the clockwise or counterclockwise direction in FIG. 4 with the contact portion with the reinforcing member 23 as a fulcrum. .. On the other hand, in the present embodiment, the contact width of the fixing member 26 that abuts on the reinforcing member 23 without the fixing member 26 being biased toward the upstream side in the transport direction or the downstream side in the transport direction and abuts on the reinforcing member 23. Since the distance B) is set sufficiently large, the fixing member 26 that receives the pressure contact force at the nip portion is supported by the reinforcing member 23 in a well-balanced manner, and the fixing member 26 collapses with the contact portion with the reinforcing member 23 as a fulcrum. It becomes difficult.

Further, in the first embodiment, since only the portion of the fixing member 26 divided into the upstream side protruding portion 26a and the downstream side protruding portion 26b is configured to abut on the reinforcing member 23, the upstream side of the fixing member 26 Since the contact area between the reinforcing member 23 and the fixing member 26 can be reduced as compared with the case where one plane formed over a wide area from the side to the downstream side abuts on the reinforcing member 23, the fixing member 26 can be reduced. It becomes difficult for heat to be transferred to. That is, the amount of heat transferred from the fixing belt 21 to the reinforcing member 26 through the fixing member 26 in the nip portion can be reduced (the amount of heat escaping from the fixing belt 21 to the reinforcing member 23 via the fixing member 26). Can be reduced.). In particular, when the thickness of the fixing belt 21 is reduced (for example, when the thickness is set to 160 μm or less) or when the nip width is set wide, the amount of heat easily moves from the fixing belt 21 to the fixing member 26. Therefore, a configuration that reduces the contact area between the reinforcing member 23 and the fixing member 26 as in the first embodiment is useful.

Here, in the fixing member 26 in the first embodiment, with reference to FIGS. 7 and 9, a plurality of rows of protrusions (upstream side protrusions 26a and downstream side protrusions 26b) are respectively. It is divided into a plurality of parts at intervals in the width direction (the left-right directions of FIGS. 7 and 9). Specifically, in the first embodiment, eight upstream-side protruding portions 26a and eight downstream-side protruding portions 26b are formed at substantially equal intervals in the width direction, respectively. With such a configuration, the contact area between the reinforcing member 23 and the fixing member 26 can be further reduced, so that the above-mentioned effect can be more reliably exhibited.
In the first embodiment, the protrusions 26a and 26b of the plurality of rows are configured to be in surface contact with the facing surfaces 23a of the reinforcing member 23, respectively, but in order to further ensure the above-mentioned effect, the plurality of rows are arranged. The protrusions 26a and 26b may be configured to make line contact or point contact (or contact with each other in a state close to the contact surface 23a) of the reinforcing member 23, respectively. Further, in the first embodiment, two rows of protrusions, an upstream side protrusion 26a and a downstream side protrusion 26b, are provided as a plurality of rows of protrusions, but three or more rows of protrusions are provided as the plurality of rows of protrusions. Can also be provided.

Further, in the first embodiment, with reference to FIG. 4, when the fixing member 26 is viewed in a cross section orthogonal to the width direction, a virtual straight line passing through the center of the transport direction in the nip portion and orthogonal to the transport direction (FIG. 1). It is a straight line shown by the alternate long and short dash line of No. 4).
With such a configuration, the fixing member 26 that has received the pressure contact force at the nip portion is more easily supported by the reinforcing member 23 in a well-balanced manner, and the fixing member 26 is less likely to fall down.

Further, in the first embodiment, as shown in FIG. 4, the fixing member 26 and the reinforcing member 23 are in contact with each other on the upstream side in the transport direction, where A is the length (nip width) of the nip portion with respect to the transport direction of the recording medium. The length from the contacting upstream contact portion to the downstream contact portion where the fixing member 26 and the reinforcing member 23 abut on the downstream side in the transport direction is defined as B, and the reinforcing member 23 faces the fixing member 26 in the transport direction. When the length of the surface 23a is C,
A <B <C
Is formed so that the relationship is established.
Further, the range of the nip portion (the range of A in FIG. 4) is the range from the upstream side contact portion to the downstream side contact portion (the range of B in FIG. 4) with respect to the transport direction. ), And the range from the upstream contact portion to the downstream contact portion (the range B in FIG. 4) is the range of the facing surface 23a of the reinforcing member 23 (the range C in FIG. 4). It is formed so as to be included in.).
In other words, the range of the nip width is included in the range of the transport direction (the vertical direction in FIG. 4) of the fixing member 26 that abuts on the reinforcing member 23. Further, the range of the fixing member 26 in contact with the reinforcing member 23 in the transport direction is included in the range of the facing surface 23a of the reinforcing member 23 in the transport direction.
With such a configuration, the fixing member 26 that has received the pressure contact force at the nip portion is more easily supported by the reinforcing member 23 in a well-balanced manner, and the fixing member 26 is less likely to fall down.

Here, with reference to FIGS. 7 to 11, the sheet-shaped member 22 has a plurality of holes that fit into a plurality of rows of protrusions (upstream side protrusions 26a and downstream side protrusions 26b). 22b is formed. The sheet-shaped member 22 is installed so as to be in close contact with the fixing member 26 along the circumferential direction at positions other than the protrusions 26a and 26b in a plurality of rows.
Specifically, as shown in FIG. 10, the sheet-shaped member 22 has a rectangular shape when unfolded as a single component. At both ends of the rectangular sheet-shaped member 22, a plurality of holes 22a and 22b (holes that fit into the protrusions 26a and 26b) and screw holes 22c (screws of the screws 24) are provided. It is a hole for inserting the portion.) And is formed.
Then, when the sheet-shaped member 22 is overlaid on the fixing member 26, both ends of the rectangle are folded between the upstream side protruding portion 26a and the downstream side protruding portion 26b (between the plurality of rows of protruding portions) and polymerized. A portion (a region surrounded by a broken line in FIG. 8, which is a hatched region in FIG. 10) will be formed. Then, as shown in FIG. 8, the plate-shaped member 28 (fixing plate) is fixed to the fixing member 26 by a plurality of screws 24 so as to sandwich the overlapping portion of the sheet-shaped member 22. Specifically, the plate-shaped member 28 is placed on the fixing member 26 so as to sandwich the polymerized portion of the sheet-shaped member 22 via the polymerized portion, and the screw hole portion 28c (see FIG. 11) of the plate-shaped member 28 can be referred to. ) And the screw hole portion 22c of the sheet-shaped member 22, and the screw portion of the screw 24 is screwed into the female screw portion 26c of the fixing member 26 (see FIG. 9B). Here, the plurality of screws 24 are formed so that the height of the screw heads exceeds the heights of the protrusions 26a and 26b and does not come into contact with the reinforcing member 23.

As described above, in the sheet-shaped member 22, the end portion corresponding to the upstream side in the transport direction and the end portion corresponding to the downstream side in the transport direction at the time of deployment are fixedly held on the fixing member 26. Therefore, in addition to the case where the sheet-shaped member 22 receives a frictional force with the fixing belt 21 traveling toward the downstream side (during the normal fixing step), the sheet-shaped member 22 is directed toward the upstream side. Even when a frictional force is applied between the fixing belt 21 and the fixing belt 21 (for example, when the fixing belt 21 or the pressure roller 31 is manually rotated in the reverse direction during jam processing), the sheet-like member 22 is used. This will prevent problems such as gaps between the fixing member 26 and the fixing member 26 and wrinkles.
In particular, in the present embodiment, the overlapping portion of the sheet-shaped member 22 is sandwiched between the plate-shaped members 28, and the plate-shaped members 28 are fastened to the fixing member 26 with a plurality of screws 24 arranged substantially evenly in the width direction. Therefore, as compared with other fixing and holding methods (for example, when the polymerized portion is bonded with an adhesive, or when the polymerized portion is hook-shaped and hooked on the protruding portions 26a and 26b), the fixing member 26 is used. The sheet-shaped member 22 can be stably and firmly fixed to the surface.

Further, the hole portions 22a and 22b of the sheet-shaped member 22 are fitted into the protruding portions 26a and 26b of the fixing member 26, and the plate-shaped member 28 and the screw 24 are placed between the protruding portions 26a and 26b (central portion in the transport direction). Since it is installed, the fixing member 26 in the state where the sheet-shaped member 22 is installed is made compact.
Further, since the fixing member 26 in which the sheet-shaped member 22 is installed can be managed in units of one sub-assembled part, the parts manageability and the assembling property at the time of manufacturing and maintenance are improved. be able to.
Further, since the sheet-shaped member 22 is fitted and held in a plurality of protruding portions 26a and 26b divided at substantially equal intervals in the width direction, even if the sheet-shaped member 22 receives a sliding contact force, a plurality of hole portions are formed. It is easy to apply force evenly to 22a and 22b, and it is possible to reduce the problem that the sheet-shaped member 22 is damaged by local stress concentration.

As described above, in the first embodiment, the fixing member 26 has a plurality of rows of protruding portions 26a and 26b protruding toward the reinforcing member 23 so as to be in contact with the reinforcing member 23. Has been done. As a result, the warm-up time and the first print time are short, and even when the speed of the device is increased, fixing failure does not occur, and the problem that the fixing member 26 in the state where the reinforcing member 23 is in pressure contact is collapsed is reduced. can do.

In the first embodiment, the fixing belt 21 having a multi-layer structure is used as the fixing belt, but an endless fixing film made of polyimide, polyamide, fluororesin, metal or the like can also be used as the fixing belt. And even in that case, the same effect as that of the first embodiment can be obtained.

Embodiment 2.
The second embodiment of the present invention will be described in detail with reference to FIG.
FIG. 12 is a configuration diagram showing the fixing device according to the second embodiment, and is a diagram corresponding to FIG. 2 according to the first embodiment. The fixing device according to the second embodiment is different from that of the first embodiment in that the fixing belt 21 is heated by electromagnetic induction.

As shown in FIG. 12, the fixing device 20 in the second embodiment also has the fixing belt 21 (belt member), the fixing member 26, the reinforcing member 23, and the pressure roller 31 (as in the first embodiment). (Heating rotating body), temperature sensor 40, sheet-shaped member 22, screw 24, plate-shaped member 28 (fixing plate), and the like.
Further, also in the second embodiment, similarly to the first embodiment, a plurality of rows of protrusions (upstream) protruding from the fixing member 26 toward the facing surface 23a of the reinforcing member 23 so as to abut against the reinforcing member 23. A side protrusion 26a and a downstream side protrusion 26b) are formed.

Here, in the fixing device 20 according to the second embodiment, an induction heating unit 50 is installed as a heating means instead of the heater 25. The fixing belt 21 in the second embodiment is heated by electromagnetic induction by the induction heating unit 50, unlike the one of the first embodiment in which the fixing belt 21 is heated by the radiant heat of the heater 25.

The induction heating unit 50 is composed of an exciting coil, a core, a coil guide, and the like. The excitation coil is formed by extending a litz wire, which is a bundle of thin wires, in the width direction (vertical to the paper surface in FIG. 12) so as to cover a part of the fixing belt 21. The coil guide is made of a resin material having high heat resistance and holds an exciting coil and a core. The core is a semi-cylindrical member made of a ferromagnet such as ferrite (specific magnetic permeability is about 1000 to 3000), and is a center core or a center core in order to form an efficient magnetic flux toward the fixing belt 21. A side core is provided. The core is installed so as to face the exciting coil extending in the width direction.
On the other hand, the fixing belt 21 has a heat generating layer (for example, an elastic layer and a mold release layer) that is electromagnetically induced and heated by the induction heating unit 50, in addition to the base material layer, the elastic layer, and the mold release layer described in the first embodiment. It can be formed between the layer and the base material layer can be used as a heat generating layer). As the material of the heat generating layer, nickel, stainless steel, iron, copper, cobalt, chromium, aluminum, gold, platinum, silver, tin, palladium, an alloy composed of a plurality of metals among these, and the like can be used.

The fixing device 20 configured in this way operates as follows.
When the fixing belt 21 is rotationally driven in the direction of the arrow in FIG. 12, the fixing belt 21 is heated at a position facing the induction heating unit 50. Specifically, by passing a high-frequency alternating current through the exciting coil, the magnetic field lines are formed so as to be alternately switched in both directions around the fixing belt 21. At this time, an eddy current is generated on the surface of the heat generating layer of the fixing belt 21, and Joule heat is generated by the electric resistance of the heat generating layer itself. The heat generation layer is electromagnetically induced and heated by this Joule heat, and the fixing belt 21 is heated.
In addition, in order to efficiently perform electromagnetic induction heating of the fixing belt 21, it is preferable to configure the induction heating unit 50 so as to face the entire circumferential direction of the fixing belt 21.

As described above, also in the second embodiment, the fixing members 26 have the protruding portions 26a and 26b protruding toward the reinforcing member 23 so as to be in contact with the reinforcing member 23. , Multiple rows are formed along the transport direction. As a result, the warm-up time and the first print time are short, and even when the speed of the device is increased, fixing failure does not occur, and the problem that the fixing member 26 in the state where the reinforcing member 23 is in pressure contact is collapsed is reduced. can do.

In the second embodiment, the fixing belt 21 is heated by electromagnetic induction heating, but the fixing belt 21 can also be heated by the heat of the resistance heating element. Specifically, the resistance heating element is brought into contact with a part or all of the inner peripheral surface or the outer peripheral surface of the fixing belt 21. The resistance heating element is a planar heating element such as a ceramic heater, and power supply units are connected to both ends thereof. Then, when a current is passed through the resistance heating element, the resistance heating element heats up due to the electric resistance of the resistance heating element itself, and heats the fixing belt 21 in contact with the resistance heating element.
Even in such a case, by providing the upstream side protrusion 26a and the downstream side protrusion 26b on the fixing member 26, the same effect as that of the second embodiment can be obtained.

It should be noted that the present invention is not limited to each of the above-described embodiments, and within the scope of the technical idea of the present invention, each of the above-described embodiments may be appropriately modified in addition to those suggested in the above-described embodiments. Is clear. Further, the number, position, shape and the like of the constituent members are not limited to each of the above-described embodiments, and the number, position, shape and the like suitable for carrying out the present invention can be used.

(Additional note)
(Appendix 1)
A flexible, endless fixing belt that heats and melts the toner image while traveling in a predetermined direction.
A fixing member fixed to the inner peripheral surface side of the fixing belt and press-contacting with the pressure rotating body via the fixing belt to form a nip portion to which the recording medium is conveyed.
A reinforcing member fixed to the inner peripheral surface side of the fixing belt and abutting against the fixing member from the inside of the fixing belt to reinforce the fixing member.
Equipped with
The fixing member is provided with a plurality of rows of protrusions protruding toward the facing surface of the reinforcing member so as to be in contact with the reinforcing member along the transport direction of the recording medium.
(Appendix 2)
The plurality of rows of protrusions are an upstream protrusion that protrudes toward the facing surface of the reinforcing member so as to abut on the reinforcing member on the upstream side in the transport direction, and the reinforcing member on the downstream side in the transport direction. The fixing device according to Appendix 1, wherein the fixing device is a downstream-side protruding portion that protrudes toward the facing surface of the reinforcing member so as to be in contact with the reinforcing member.
(Appendix 3)
The fixing device according to Supplementary Note 1 or 2, wherein each of the plurality of rows of protrusions is divided into a plurality of protrusions at intervals in the width direction.
(Appendix 4)
It is made of a low friction material and includes a sheet-like member that is covered along the circumferential direction of the fixing member so as to be interposed between the fixing member and the fixing belt at the position of the nip portion in the width direction. ,
The sheet-shaped member is provided with a plurality of holes that fit into the protrusions of the plurality of rows, and is installed so as to be in close contact with the fixing member along the circumferential direction at a position other than the protrusions of the plurality of rows. The fixing device according to the appendix 1 to 3, wherein the fixing device is characterized by the above.
(Appendix 5)
The sheet-shaped member has a rectangular shape when unfolded as a single component, and when it is covered with the fixing member, both ends of the rectangle are folded between the protrusions of the plurality of rows to form a polymerized portion. Formed,
The fixing device according to Appendix 4, wherein the plate-shaped member is fixed to the fixing member by a plurality of screws so as to sandwich the polymerized portion of the sheet-shaped member.
(Appendix 6)
The fixing device according to Appendix 4 or Appendix 5, wherein the sheet-shaped member is made of a fiber material impregnated with a lubricant.
(Appendix 7)
The fixing member is characterized in that it is formed so as to be line-symmetric with respect to a virtual straight line passing through the center of the nip portion in the transport direction and orthogonal to the transport direction when viewed in a cross section orthogonal to the width direction. The fixing device according to any one of Supplementary note 1 to Supplementary note 6.
(Appendix 8)
A holding member that holds both ends in the width direction of the fixing belt, and
A heating means that heats the fixing belt by facing or contacting the fixing belt.
The fixing device according to any one of Supplementary note 1 to Supplementary note 7, further comprising.
(Appendix 9)
An image forming apparatus comprising the fixing apparatus according to any one of Supplementary note 1 to Supplementary note 8.

(Additional note)
(Appendix 11)
A flexible, endless fixing belt and
A fixing member arranged on the inner peripheral surface side of the fixing belt and forming a nip portion in which a recording medium is conveyed by being pressed against a pressurized rotating body via the fixing belt.
A heater that directly faces at least a part of the fixing belt other than the nip portion and heats the fixing belt.
A reinforcing member arranged between the fixing member and the heater on the inner peripheral surface side of the fixing belt and abutting against the fixing member to reinforce the fixing member.
A holding member that holds both ends in the width direction of the fixing belt, and
Equipped with
The reinforcing member is not in contact with the fixing belt when the fixing belt is rotated, and the reinforcing member is not in contact with the fixing belt.
The fixing member is provided with a plurality of rows of protrusions protruding toward the facing surface of the reinforcing member so as to be in contact with the reinforcing member along the transport direction of the recording medium, and the low friction sheet-like member is provided over the width direction. A fixing device characterized in that it comes into contact with the fixing belt via the fixing device.
(Appendix 12)
The plurality of rows of protrusions are an upstream protrusion that abuts on the facing surface on the upstream side in the transport direction and a downstream protrusion that abuts on the facing surface on the downstream side in the transport direction. The fixing device according to Appendix 11, which is a feature.
(Appendix 13)
The fixing device according to Supplementary Note 11 or 12, wherein each of the plurality of rows of protrusions is divided into a plurality of protrusions at intervals in the width direction.
(Appendix 14)
The low friction sheet-like member includes a plurality of holes and has a plurality of holes.
The fixing device according to Supplementary Note 11 to 13, wherein the plurality of holes are fitted into the plurality of rows of protrusions.
(Appendix 15)
The low-friction sheet-like member has a rectangular shape when unfolded as a single component, and when it is covered with the fixing member, both ends of the rectangle are folded between the protrusions of the plurality of rows and polymerized. The part is formed,
The fixing device according to Appendix 14, wherein a contact member that comes into contact with the fixing member via the polymerization portion is provided between the protrusions of the plurality of rows.
(Appendix 16)
The fixing device according to Appendix 14 or Appendix 15, wherein the low-friction sheet-like member is formed of a fiber material impregnated with a lubricant.
(Appendix 17)
The fixing member is characterized in that it is formed so as to be line-symmetric with respect to a virtual straight line passing through the center of the nip portion in the transport direction and orthogonal to the transport direction when viewed in a cross section orthogonal to the width direction. The fixing device according to any one of Supplementary note 11 to Supplementary note 16.
(Appendix 18)
The reinforcing member is an upstream side wall portion provided on the upstream side with respect to the facing surface and substantially perpendicular to the fixing member, and the fixing member on the downstream side with respect to the facing surface. The fixing device according to any one of Supplementary note 11 to Supplementary note 17, wherein the fixing device is provided substantially vertically in the direction opposite to the above and has a downstream side wall portion facing the upstream side wall portion.
(Appendix 19)
Let A be the length of the nip portion with respect to the transport direction of the recording medium, and the fixing member is located on the downstream side in the transport direction from the upstream contact portion where the fixing member and the reinforcing member abut on the upstream side in the transport direction. When the length to the downstream contact portion where the reinforcing member and the reinforcing member abut is set to B,
A <B
As the relationship is established
The present invention is characterized in that the range of the nip portion is included in the range from the upstream side contact portion to the downstream side contact portion with respect to the transport direction. The fixing device described.
(Appendix 20)
The fixing device according to any one of Supplementary note 11 to Supplementary note 19, wherein each of the plurality of rows of protrusions is formed so as to make line contact or point contact with the facing surface of the reinforcing member.
(Appendix 21)
The reinforcing member is provided with a heat insulating member on a part or all of the surface facing the heater.
The fixing device according to any one of Supplementary note 11 to Supplementary note 20, wherein the fixing member is made of a material having heat insulating properties.
(Appendix 22)
An image forming apparatus comprising the fixing apparatus according to any one of Supplementary note 11 to Supplementary note 21.

1 Image forming device main body (device main body),
20 Fixing device,
21 Fixing belt (fixing member),
22 Sheet-shaped member,
23 Reinforcing member,
24 screws (fixing screws),
25 Heater (heating means),
26 Fixing member,
26a upstream protrusion, 26b downstream protrusion,
28 Plate-shaped member (fixing plate),
29 Flange (holding member),
31 Pressurized roller (pressurized rotating body).

Japanese Patent No. 2010-96782

Claims (13)

A flexible, endless fixing belt and
A fixing member arranged on the inner peripheral surface side of the fixing belt and forming a nip portion in which a recording medium is conveyed by being pressed against a pressurized rotating body via the fixing belt.
A heater that directly faces at least a part of the fixing belt other than the nip portion and heats the fixing belt.
A reinforcing member arranged between the fixing member and the heater on the inner peripheral surface side of the fixing belt and abutting on the fixing member, and a reinforcing member.
A guide member that guides the fixing belt at both ends in the width direction of the fixing belt, and
Equipped with
The reinforcing member is not in contact with the fixing belt when the fixing belt is rotated, and the reinforcing member is not in contact with the fixing belt.
The fixing member is provided with a plurality of rows of protrusions protruding toward the facing surface of the reinforcing member so as to be in contact with the reinforcing member along the direction orthogonal to the width direction, and the contact portion of the sheet-like member is provided. In contact with the fixing belt via
The sheet-shaped member is provided so as to cover the fixing member by forming a plurality of holes fitted to the protruding portion on the upstream side and the downstream side of the contact portion, respectively .
The upstream side and the downstream side of the sheet-shaped member overlapped between the protrusions of the plurality of rows on the opposite side to the side where the fixing belt of the fixing member and the sheet-shaped member contact . A polymerized part is formed,
The polymerization unit has a through-hole portion penetrating from one surface of the polymerization unit to the other surface, and is fixed to the fixing member. The fixing device according to claim 1, wherein the protruding portion has a length in the width direction as compared with a length in the transport direction. The plurality of rows of protrusions are an upstream protrusion that abuts on the facing surface on the upstream side in the transport direction and a downstream protrusion that abuts on the facing surface on the downstream side in the transport direction. The fixing device according to claim 1 or 2, which is characterized. The fixing device according to any one of claims 1 to 3, wherein the plurality of rows of protrusions are a plurality of protrusions spaced apart in the width direction. The fixing device according to any one of claims 1 to 4, wherein each of the plurality of rows of protrusions is a plurality of protrusions spaced apart in the width direction. The fixing device according to claim 4, wherein the intervals are evenly spaced. The fixing device according to any one of claims 1 to 6, wherein the through-hole portions are evenly arranged in the width direction. A flexible, endless fixing belt and
A fixing member arranged on the inner peripheral surface side of the fixing belt and forming a nip portion in which a recording medium is conveyed by being pressed against a pressurized rotating body via the fixing belt.
A heater that directly faces at least a part of the fixing belt other than the nip portion and heats the fixing belt.
A reinforcing member arranged between the fixing member and the heater on the inner peripheral surface side of the fixing belt and abutting on the fixing member, and a reinforcing member.
A guide member that guides the fixing belt at both ends in the width direction of the fixing belt, and
Equipped with
The reinforcing member is not in contact with the fixing belt when the fixing belt is rotated, and the reinforcing member is not in contact with the fixing belt.
The fixing member is provided with a plurality of rows of protrusions protruding toward the facing surface of the reinforcing member so as to be in contact with the reinforcing member along the direction orthogonal to the width direction, and the contact portion of the sheet-like member is provided. In contact with the fixing belt via
The sheet-shaped member is provided so as to cover the fixing member by forming a plurality of holes fitted to the protruding portion on the upstream side and the downstream side of the contact portion, respectively .
The upstream side and the downstream side of the sheet-shaped member overlapped between the protrusions of the plurality of rows on the opposite side to the side where the fixing belt of the fixing member and the sheet-shaped member contact . A polymerized part is formed,
The polymerization unit is a fixing device characterized in that it is sandwiched and fixed between the fixing member and a plate-shaped member. A flexible, endless fixing belt and
A fixing member arranged on the inner peripheral surface side of the fixing belt and forming a nip portion in which a recording medium is conveyed by being pressed against a pressurized rotating body via the fixing belt.
A heater that directly faces at least a part of the fixing belt other than the nip portion and heats the fixing belt.
A reinforcing member arranged between the fixing member and the heater on the inner peripheral surface side of the fixing belt and abutting on the fixing member, and a reinforcing member.
A guide member that guides the fixing belt at both ends in the width direction of the fixing belt, and
Equipped with
The reinforcing member is not in contact with the fixing belt when the fixing belt is rotated, and the reinforcing member is not in contact with the fixing belt.
The fixing member is provided with a plurality of rows of protrusions protruding toward the facing surface of the reinforcing member so as to be in contact with the reinforcing member along the direction orthogonal to the width direction, and the contact portion of the sheet-like member is provided. In contact with the fixing belt via
The sheet-shaped member is provided so as to cover the fixing member by forming a plurality of holes fitted to the protruding portion on the upstream side and the downstream side of the contact portion, respectively .
The upstream side and the downstream side of the sheet-shaped member overlapped between the protrusions of the plurality of rows on the opposite side to the side where the fixing belt of the fixing member and the sheet-shaped member contact . A polymerized part is formed,
The polymerized portion is sandwiched and fixed between the fixing member and the plate-shaped member, and is fixed.
The polymerization unit has a through-hole portion penetrating from one surface of the polymerization unit to the other surface, and is fixed to the fixing member. The fixing device according to claim 8 or 9, wherein the plate-shaped member is fixed to the fixing member. The fixing device according to any one of claims 1 to 10, wherein the sheet-shaped member is impregnated with a lubricant. The fixing device according to any one of claims 1 to 11, further comprising a temperature detecting means facing the surface of the fixing belt. An image forming apparatus comprising the fixing apparatus according to any one of claims 1 to 12.

Images