Fixing device and image forming apparatus

Abstract

The present invention relates to a fixing device and an image forming apparatus, which can shorten a start-up time of the fixing device and improve an energy saving effect by effectively utilizing heat of a reflection plate without taking heat of a fixing member even in a case where a steam chamber having high heat conductivity is used for a nip forming member. It includes: a fixing belt which is annular and rotatable; a pressure roller which is opposed to the fixing belt and is provided to be rotatable; a heater which is provided inside the fixing belt and heats the fixing belt; a nip forming member which is provided inside the fixing belt and includes a steam chamber which forms a nip in opposition to the pressure roller; a reinforcing member which is provided inside the fixing belt and supports the nip forming member; and a reflection plate which is provided between the heater and the reinforcing member, reflects heat from the heater toward the fixing belt, and the steam chamber included in the nip forming member is in contact with the reflection plate through a heat conducting member.

Description

Technical Field

[0001] This invention relates to a fixing apparatus and an image forming apparatus. Background Technology

[0002] In electrophotographic fixing devices, to improve the thermal conductivity of the clamping forming member that contacts the inner side of the fixing component, a technique has been developed to use a clamping forming member made of metal (copper, aluminum, etc.) (see Patent Document 2). Furthermore, a technique has been developed to improve thermal conductivity by sealing a working fluid inside a hollow structure, such as a heat pipe, and repeatedly vaporizing and liquefying the working fluid (see Patent Document 1). Additionally, to suppress end temperature rise during small-sized paper passage and improve heat uniformity, a technique has been developed to bring the clamping forming member and the support member into thermal contact (see Patent Document 2).

[0003] However, in the above-mentioned clamping forming member, due to the improved thermal conductivity, the heat of the fixing member is taken away by the clamping forming member during preheating, and the heat escapes to the member holding the clamping forming member.

[0004] The present invention was made in view of the above circumstances, and its object is to provide a fixing device and an image forming device that, even when a steam chamber with high thermal conductivity is used to hold the forming component, can effectively utilize the heat of the reflector without taking away the heat of the fixing component, thereby shortening the start-up time of the fixing device and improving energy saving.

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2020-86350

[0006] [Patent Document 2] Japanese Patent Application Publication No. 2022-37693 Summary of the Invention

[0007] To solve the above problems and achieve the objective, the fixing device of the present invention includes: an annular fixing belt that is rotatable; a pressure roller that is opposite to the fixing belt and is configured to be rotatable; a heater that is disposed inside the fixing belt and heats the fixing belt; a clamping forming member that is disposed inside the fixing belt and includes a steam chamber that is opposite to the pressure roller and forms a clamping portion; a reinforcing member that is disposed inside the fixing belt and supports the clamping forming member; and a reflector that is disposed between the heater and the reinforcing member to reflect heat from the heater toward the fixing belt, wherein the steam chamber included in the clamping forming member is in contact with the reflector through a heat conduction member.

[0008] According to the present invention, even when a steam cavity with high thermal conductivity is used to hold the forming component, the heat of the reflector is effectively utilized without taking away the heat of the fixing component, thereby achieving the effect of shortening the start-up time of the fixing device and improving energy saving. Attached Figure Description

[0009] Figure 1 The diagram shown is an example of the structure of the image forming apparatus of this embodiment.

[0010] Figure 2 This is a diagram illustrating an example of the fixing device included in the image forming apparatus of this embodiment.

[0011] Figure 3 This is a diagram illustrating an example of the fixing device included in the image forming apparatus of this embodiment.

[0012] Figure 4 This is a diagram illustrating an example of the fixing device included in the image forming apparatus of this embodiment.

[0013] Figure 5 This is a diagram illustrating an example of the fixing device included in the image forming apparatus of this embodiment.

[0014] Figure 6 The diagram shown is an example of a schematic cross-sectional structure of a fixing device.

[0015] Figure 7 The diagram shown is an example of a schematic cross-sectional structure of a fixing device.

[0016] Figure 8 The diagram shown is an example of a schematic cross-sectional structure of a fixing device.

[0017] Figure 9 The diagram shown is an example of a schematic cross-sectional structure of a fixing device.

[0018] Figure 10 The diagram shown is an example of a schematic cross-sectional structure of a fixing device.

[0019] Figure 11 The diagram shown is an example of a schematic cross-sectional structure of a fixing device.

[0020] Figure 12 This is a cross-sectional view of an example of the fixing device of this embodiment.

[0021] Figure 13 This is a diagram illustrating an example of the fixing apparatus of this embodiment.

[0022] Figure 14 This is a diagram illustrating an example of the fixing apparatus of this embodiment.

[0023] Figure 15 This is a diagram illustrating an example of the fixing apparatus of this embodiment.

[0024] Figure 16 This is a diagram illustrating an example of the fixing apparatus of this embodiment.

[0025] Figure 17 This is a diagram illustrating an example of the fixing apparatus of this embodiment.

[0026] Figure 18 This is a diagram illustrating an example of the fixing apparatus of this embodiment.

[0027] Figure 19 This is a diagram illustrating an example of the fixing apparatus of this embodiment.

[0028] Figure 20 This is a diagram illustrating an example of the fixing apparatus of this embodiment. Detailed Implementation

[0029] Hereinafter, embodiments of the fixing apparatus and the image forming apparatus will be described in detail with reference to the accompanying drawings.

[0030] The diagram shown is an example of the structure of the image forming apparatus of this embodiment. Figures 2-5 This is a diagram illustrating an example of the fixing device included in the image forming apparatus of this embodiment. Figures 6-11 The diagram shown is an example of a schematic cross-sectional structure of a fixing device. First, through... Figure 1 The overall structure and operation of the image forming apparatus 1 will be explained. For example... Figure 1 As shown, the image forming apparatus 1 in this embodiment is a serial color printer. Four toner containers 102Y, 102M, 102C, and 102K, corresponding to each color (yellow, magenta, cyan, and black), are detachably (replaceably) arranged in the container housing 101 located above the main body of the image forming apparatus 1. An intermediate transfer unit 85 is arranged below the container housing 101. Imaging units 4Y, 4M, 4C, and 4K, corresponding to each color (yellow, magenta, cyan, and black), are arranged side-by-side facing the intermediate transfer belt 78 of the intermediate transfer unit 85.

[0031] Each of the image-forming units 4Y, 4M, 4C, and 4K is equipped with a photosensitive drum 5Y, 5M, 5C, and 5K, respectively. Additionally, a charging unit 75, a developing unit 76, a cleaning unit 77, and a static removal unit (not shown) are respectively arranged around each photosensitive drum 5Y, 5M, 5C, and 5K. Then, after image-forming processes (charging, exposure, developing, transfer, and cleaning processes) are performed on the surface of each photosensitive drum 5Y, 5M, 5C, and 5K, images of various colors are formed on the surface of each photosensitive drum 5Y, 5M, 5C, and 5K.

[0032] The photosensitive drums 5Y, 5M, 5C, and 5K are operated by motors. Figure 1 The surfaces of the photosensitive drums 5Y, 5M, 5C, and 5K are uniformly charged at the charging unit 75 (i.e., the charging process). Afterward, the surfaces of the photosensitive drums 5Y, 5M, 5C, and 5K reach the irradiation position of the laser L from the exposure unit 3, and an electrostatic latent image corresponding to each color is formed by exposure scanning at that position (i.e., the exposure process).

[0033] Subsequently, the surfaces of photosensitive drums 5Y, 5M, 5C, and 5K reach positions facing the developing section 76, where the electrostatic latent image is developed to form toner images of various colors (i.e., the developing process). Next, the surfaces of photosensitive drums 5Y, 5M, 5C, and 5K reach positions facing the intermediate transfer belt 78 and the first transfer bias rollers 79Y, 79M, 79C, and 79K, where the toner images on the photosensitive drums 5Y, 5M, 5C, and 5K are transferred to the intermediate transfer belt 78 (i.e., a first transfer process). At this point, trace amounts of untransferred toner remain on the surfaces of the photosensitive drums 5Y, 5M, 5C, and 5K.

[0034] Next, the surfaces of photosensitive drums 5Y, 5M, 5C, and 5K reach a position opposite to the cleaning section 77, where the cleaning blade of the cleaning section 77 mechanically recovers any remaining untransferred toner (i.e., the cleaning process). Finally, the surfaces of photosensitive drums 5Y, 5M, 5C, and 5K reach a position opposite to the static elimination section, where any remaining potential on the photosensitive drums 5Y, 5M, 5C, and 5K is removed. This completes a series of imaging processes performed on the photosensitive drums 5Y, 5M, 5C, and 5K.

[0035] Next, the toner images of various colors formed on each photosensitive drum after the developing process are superimposed onto the surface of the intermediate transfer belt 78 and transferred. Thus, a color image is formed on the intermediate transfer belt 78. Here, the intermediate transfer unit 85 consists of the intermediate transfer belt 78, four primary transfer bias rollers 79Y, 79M, 79C, and 79K, a secondary transfer support roller 82, a cleaning support roller 83, a tension roller 84, and an intermediate transfer cleaning section 80. The intermediate transfer belt 78 is tensioned and supported by three rollers 82-84, and is also driven by the rotation of one roller 82. Figure 1 Move around in the direction of the arrow in the image.

[0036] Four primary transfer bias rollers 79Y, 79M, 79C, and 79K, along with photosensitive drums 5Y, 5M, 5C, and 5K respectively, clamp the intermediate transfer belt 78 to form a primary transfer clamping section. Then, a transfer bias with the opposite polarity to the toner is applied to the primary transfer bias rollers 79Y, 79M, 79C, and 79K. The intermediate transfer belt 78 then moves in the direction of the arrow and passes sequentially through the primary transfer clamping sections of each primary transfer bias roller 79Y, 79M, 79C, and 79K. In this way, the toner images of each color on the photosensitive drums 5Y, 5M, 5C, and 5K are superimposed onto the intermediate transfer belt 78 and transferred in one step.

[0037] Next, the intermediate transfer belt 78, with overlapping and transferred toner images of various colors, reaches a position facing the secondary transfer roller 89. At this position, the secondary transfer support roller 82 and the secondary transfer roller 89 clamp the intermediate transfer belt 78 to form a secondary transfer clamping section. Then, the four-color toner image formed on the intermediate transfer belt 78 is transferred to the sheet P, which is being conveyed to the secondary transfer clamping section. At this point, untransferred toner remains on the intermediate transfer belt 78. Afterward, the intermediate transfer belt 78 reaches the intermediate transfer cleaning section 80. At this position, the untransferred toner on the intermediate transfer belt 78 is recovered. Thus, the series of transfer processes performed on the intermediate transfer belt 78 is completed.

[0038] Here, the sheet P, which is moved to the secondary transfer clamping section, is fed from the paper supply section 12 located below the image forming apparatus 1 via the paper supply roller 97 or the alignment roller pair 98 (timing roller pair). Specifically, multiple sheets of paper, etc., are stacked and stored in the paper supply section 12. Then, when the paper supply roller 97... Figure 1 When driven to rotate counterclockwise, the uppermost sheet P is fed into the space between the alignment rollers 98.

[0039] The sheet P, once conveyed to the registration roller pair 98, stops at the roller clamping position where the rotation drive of the registration roller pair 98 has ceased. Then, after timing alignment with the color image on the intermediate transfer belt 78, the registration roller pair 98 is rotated, and the sheet P is conveyed toward the secondary transfer clamping. In this way, the desired color image is transferred onto the sheet P.

[0040] Next, at the secondary transfer clamping position, the sheet P with the transferred color image is moved to the fixing unit 20. Then, at this position, the color image transferred onto the surface is fixed onto the sheet P by the heat and pressure of the fixing belt 21 and the pressure roller 31 (fixing process). Afterward, the sheet P is discharged out of the device through the gap between the paper discharge rollers 99. The sheet P discharged out of the device through the paper discharge rollers 99 is stacked sequentially onto the stacking section 100 as an output image. In this way, a series of image forming processes in the image forming apparatus are completed.

[0041] Next, through Figure 8 The structure and operation of the fixing unit 20, which is installed in the image forming apparatus body 1, will be described in detail below. The fixing unit 20 is a device that heats and transports a sheet P (a sheet carrying toner in an unfixed state) simultaneously. Figure 8 , Figure 2 , Figure 3 As shown, the fixing device 20 includes: a fixing belt 21 as a belt component, a clamping and forming component 26, a reinforcing component 23, a heater 25 as a heating means (heating source), a reflector 27, a pressure roller 31 as a pressure rotating body, a temperature detection sensor 40 as a temperature detection means, etc.

[0042] Here, the fixing belt 21 is an annular belt component externally connected to the pressure roller 31 and rotating consequently with the rotation of the pressure roller 31. The fixing belt 21 is a thin, flexible annular belt. Figure 8The fixing belt 21 rotates (driven rotation) in the direction of the arrow (counterclockwise). That is, the fixing belt 21 is an example of a rotatable annular fixing belt. Starting from the inner circumferential surface (the surface that slides in contact with the clamping forming member 26), the fixing belt 21 is sequentially stacked with a substrate layer, an elastic layer, and a release layer, and its overall thickness is set to be less than 1 mm. The substrate layer of the fixing belt 21 has a thickness of 30 μm to 100 μm and is formed of a metallic material such as nickel or stainless steel, or a resin material such as polyimide. The elastic layer of the fixing belt 21 has a thickness of 100 to 300 μm and is formed of a rubber material such as silicone rubber, foamed silicone rubber, or fluororubber. By providing the elastic layer, the tiny unevenness on the surface of the fixing belt 21 in the clamping part will not be formed, and heat will be evenly transferred to the toner image T on the sheet P, thus suppressing the occurrence of orange peel image. The release layer of the fixing tape 21 has a thickness of 5μm to 50μm and is formed from materials such as PFA (a copolymer of tetrafluoroethylene and perfluoroalkoxy vinyl acid), PTFE (polytetrafluoroethylene), polyimide, polyetherimide, and PES (polyethersulfone). By setting the release layer, the release properties (peelability) of the toner (toner like T) are ensured.

[0043] A clamping forming member 26, a heater 25 (heating means), a reinforcing member 23, and a reflector 27 are provided on the inner side (inner circumferential surface side) of the fixing belt 21. Here, the clamping forming member 26 is pressed onto the pressure roller 31 via the fixing belt 21 on the inner side (inner circumferential surface side) to form a clamping part (fixing clamping part) for conveying the sheet P. That is, the pressure roller 31 is an example of a pressure roller that can rotate relative to the fixing roller 21. In addition, the clamping forming member 26 is configured to slide in contact with the inner circumferential surface of the fixing belt 21. Then, the clamping forming member 26 forms the clamping part for conveying the sheet P by pressing the fixing belt 21 onto the pressure roller 31. In addition, a steam chamber 26b is provided on the clamping side of the clamping forming member 26. That is, the clamping forming member 26 is an example of a clamping forming member that includes a steam chamber 26b disposed inside the fixing belt 21 and opposite the pressure roller 31 to form a clamping portion.

[0044] Then, the fixing belt 21 is directly heated by the radiant heat of the heating tube 25 (heating means) disposed inside it. That is, the heater 25, as a heating means, heats the fixing belt 21 in order to heat the sheet P. The heater 25 is an example of a heater disposed inside the fixing belt 21 to heat the fixing belt 21. The heater 25 (heating means) is configured to heat the circumferential area of ​​the fixing belt 21, which is different from the clamping part, as the heating area. Specifically, the heater 25, as a heating means, is a halogen heater (or a carbon heater), and its two ends are fixed to the side plate 43 of the fixing device 20 (see reference). Figure 2The heating element 25 is heated in the fixing tape 21 by radiant heat from the heater 25 (heating means) controlled by the control unit. The heating area (mainly the area facing the heater 25) in the fixing tape 21, which is different from the clamping part, is heated. Furthermore, heat is applied from the heated surface of the fixing tape 21 to the toner image T on the sheet P. The output control of the heating element 25 is based on the temperature detection results of the tape surface by a temperature sensor 40 (temperature detection means) such as a thermopile or thermistor facing the surface of the fixing tape 21. By controlling the output of the heating element 25, the temperature of the fixing tape 21 (fixing temperature) can be set to a desired temperature. In this embodiment, two heaters 25 (heating means) are provided on the inner circumferential surface of the fixing tape 21, but one or more heaters may also be provided on the inner circumferential surface of the fixing tape 21. The position of the heaters 25 and the shape of the reinforcing member 23 (described later) are not limited to this embodiment; for example, the heaters 25 and... Figure 8 In contrast, it can also be configured to face the upstream side of the fixing belt 21 in the direction of rotation, and the shape of the reinforcing member 23 can be provided accordingly.

[0045] Thus, because the fixing device 20 of this embodiment heats not only a portion of the fixing belt 21 locally, but also a large area of ​​the fixing belt 21 in the circumferential direction, it can sufficiently heat the fixing belt 21 even at high speeds and suppress the occurrence of fixing defects. In other words, because the fixing belt 21 can be heated efficiently with a relatively simple configuration, preheating time or first-print time is shortened while also achieving device miniaturization. In particular, because the fixing device 20 of this embodiment directly heats the fixing belt 21 through the heating tube 25 (heating means), it further improves the heating efficiency of the fixing belt 21 while further reducing the cost and miniaturizing the fixing device 20.

[0046] like Figure 3 As shown, the guide members 29 guide the two ends of the fixing belt 21 in the width direction from the inner circumferential surface side to maintain the fixing belt 21 in a generally cylindrical posture. Specifically, the two guide members 29 are formed of heat-resistant resin material or the like and are respectively embedded in the side plates 43 at both ends of the fixing device 20 in the width direction. The guide members 29 are provided with guide portions 29a for holding the fixing belt 21 while maintaining its generally cylindrical posture, and limiting portions for restricting the movement (biasing) of the fixing belt 21 in the width direction. In addition, the guide members 29 are arranged at both ends in the width direction other than the circumferential range of the clamping portion so as not to interfere with the clamping forming member 26 forming the clamping portion.

[0047] Furthermore, in this embodiment, the only components that contact the inner circumferential surface of the fixing belt 21 are the guide member 29 and the clamping forming member 26 (actually via the sheet member 22), which are loosely contacted at both ends in the width direction. There are no other components (with guide portions) that contact the inner circumferential surface and guide the rotation of the fixing belt 21. Thus, the fixing apparatus 20 of this embodiment, with the aim of further improving the heating efficiency of the fixing belt 21 or reducing the cost and miniaturizing the apparatus, employs a configuration that eliminates the tubular heating member and directly heats the fixing belt 21 via the heating mechanism (heating tube 25) without relying on the tubular heating member.

[0048] In this embodiment, the reinforcing member 23 is disposed inside the fixing belt 21 and abuts against the pressure roller 31 via the clamping forming member 26 and the fixing belt 21. The reinforcing member 23 is a component that strengthens the clamping forming member 26 of the clamping portion, and is integrated with the clamping forming member 26 by means of threaded fastening or the like. That is, the reinforcing member 23 is an example of a reinforcing member disposed inside the fixing belt 21 and supporting the clamping forming member 26. Figure 2 As shown, the reinforcing member 23 is formed to be longer in the width direction than the clamping forming member 26, and its two ends in the width direction are held on the side plate 43 of the fixing device 20 so as to be able to Figure 2 Up and down directions ( Figure 8 It moves in the left and right direction. Then, by the contact between the reinforcing member 23 and the pressure roller 31 via the clamping part forming member 26 and the fixing belt 21, the problem of large deformation of the clamping forming member 26 due to the pressure of the pressure roller 31 in the clamping part is suppressed. In order to meet the above functions, the reinforcing member 23 is preferably formed of a metal material with high mechanical strength such as stainless steel or iron.

[0049] Furthermore, in this embodiment, a reflector 27 is fixedly provided between the reinforcing member 23 and the heater 25. That is, the reflector 27 is an example of a reflector provided between the heater 25 and the reinforcing member 23, which reflects heat from the heater 25 toward the fixing belt 21. As a result, since the heat from the heating tube 25 toward the reinforcing member 23 (the heat that heats the reinforcing member 23 is infrared radiation) is reflected by the reflector 27 and used to heat the fixing belt 21, the heating efficiency of the fixing belt 21 can be further improved. In addition, aluminum, stainless steel, etc. can be used as the material for the reflector 27. Furthermore, even if a mirror finish or an insulating member is provided on part or all of the surface of the reinforcing member 23 facing the heating tube 25, the same effect can be obtained.

[0050] like Figure 8 As shown, the pressure roller 31, which serves as a heating rotating body, is formed by providing an elastic layer 33 on a spindle 32 (shaft portion), and is driven in a predetermined direction by a drive motor (driving means) not shown in the figure. Figure 8 The pressure roller 31 is driven to rotate clockwise. The spindle 32 of the pressure roller 31 is a hollow structure made of metal. The elastic layer 33 of the pressure roller 31 is made of materials such as silicone rubber, foamed silicone rubber, or fluororubber. Furthermore, a thin release layer made of materials such as PFA or PTFE can also be provided on the surface of the elastic layer 33. The pressure roller 31 is pressed against the fixing belt 21, forming the required clamping portion between the components of both. Additionally, as... Figure 2 As shown, a gear 45 is provided in the pressure roller 31 to mesh with the drive gear of the drive motor. The pressure roller 31 in Figure 8 The roller is driven to rotate in the direction of the arrow (clockwise). In addition, the two ends of the pressure roller 31 in the width direction are supported by bearings 42 in the side plate 43 of the fixing device 20 so that they can rotate.

[0051] Furthermore, when the elastic layer 33 of the pressure roller 31 is formed using a sponge-like material such as foamed silicone rubber, the applied pressure in the clamping part can be reduced, thus alleviating the load generated in the clamping forming member 26. Moreover, since the thermal insulation of the pressure roller 31 is improved, the heat from the fixing belt 21 is less likely to move to one side of the pressure roller 31, thereby improving the heating efficiency of the fixing belt 21.

[0052] like Figure 9 As shown, the surface of the clamping forming member 26 that slides in contact with the inner circumferential surface of the fixing belt 21 and faces the pressure roller 31 (the sliding contact surface 26b2 of the steam chamber 26b described later) is formed as a plane. That is, the sliding contact surface 26b2 of the clamping forming member 26 (the surface facing the pressure roller 31) is formed as a plane. As a result, the shape of the clamping part is approximately parallel to the image surface of the sheet P, and the fixing performance is improved due to the increased contact between the fixing belt 21 and the sheet P. Furthermore, since the curvature of the fixing belt 21 on the exit side of the clamping part is increased, the sheet P delivered by the clamping part can be easily separated from the fixing belt 21.

[0053] The following is a brief description of the normal operation of the fixing device 20 configured as described above. When the power switch of the device body 1 is turned on, power is supplied to the heating tube 25, and the pressure roller 31 moves along... Figure 8 The rotation drive in the direction of the arrow also begins. Consequently, through the frictional force between the fixing belt 21 and the pressure roller 31 in the clamping section, the fixing belt 21 also moves in the direction of the arrow. Figure 8 The arrow in the middle rotates in the direction of the driven rotation. Then, sheet P is fed from the paper feed section 12, and at the position of the secondary transfer roller 89, the unfixed color image is placed (transferred) onto sheet P. Sheet P, carrying the unfixed image T (toner image), is guided by the guide plate while... Figure 8The toner image T is conveyed in the direction of arrow Y10 and fed into the clamping portion of the fixing belt 21 and pressure roller 31, which are in a pressing state. Then, by the heating of the fixing belt 21 heated by the heating tube 25, and the pressing pressure of the clamping forming member 26 reinforced by the reinforcing member 23 and the pressure roller 31, the toner image T is fixed onto the surface of the sheet P. Then, the sheet P delivered from the clamping portion is conveyed in the direction of arrow Y11.

[0054] The following is a detailed description of the features, configuration, and operation of the fixing device 20 in this embodiment. (As previously used...) Figure 8 As explained above, the fixing apparatus 20 of this embodiment includes a fixing belt 21, a clamping forming member 26, etc. The fixing belt 21 is heated by a heater 25, which serves as a heating means, and rotates in a predetermined direction ( Figure 8 A ring-shaped belt component that rotates counterclockwise. The heater 25 is positioned facing the inner circumferential surface of the fixing belt 21. The clamping forming component 26 is disposed on the inner circumferential surface side of the fixing belt 21 and is pressed against the pressure roller 31, which is a pressure rotating body, to form a clamping part (fixing clamp) for conveying the sheet P.

[0055] Here, as Figure 9 As shown, in this embodiment, the fixing device 20 has a vapor chamber 26b in the clamping forming member 26 that slides in contact with the inner circumferential surface of the fixing belt 21. Specifically, the clamping forming member 26 mainly consists of a holding part 26a (the main body of the clamping forming member) and the vapor chamber 26b.

[0056] The holding part 26a holds the vapor chamber 26b on the side away from the clamping part (fixing clamping part) (inner side of the belt), and has rigidity to the point that it will not bend significantly even when subjected to pressure from the pressure roller 31. As the material forming the holding part 26a, resin materials (liquid crystal polymer (LCP), polyamide imide (PAI), polyethersulfone (PES), polyphenylene sulfide (PPS), polyether nitrile (PEN), polyether ether ketone (PEEK), etc.) can be used. The holding part 26a holds the vapor chamber 26b while being held by the reinforcing member 23.

[0057] The steam chamber 26b is a metal heat dissipation component that seals a working fluid such as water in the hollow portion 26b1, and has the function of instantaneously transferring heat through the vaporization and condensation of the working fluid. A capillary wick 26z (see reference) is provided in the hollow portion 26b1 of the steam chamber 26b. Figure 4 ).like Figure 4As shown, the steam chamber 26b has a capillary wick 26z (a roughly gauze-like component with fine shapes inside) provided on almost the entire surface of the inner wall surfaces 26b4 and 26b5. Through the capillary effect of the capillary wick 26z, the liquefied working fluid in the hollow part 26b1 moves, and the vaporized working fluid moves, thereby achieving high thermal conductivity and heat uniformity through heat exchange.

[0058] Furthermore, the generally rectangular frame constituting the steam chamber 26b is formed of a material with high thermal conductivity (e.g., copper, aluminum, silver, graphite, etc.). Here, in Figure 5 In this process, the sliding contact surface 26b2 of the steam chamber 26b (which is directly connected to the inner circumferential surface of the fixing belt 21 and is the surface of sliding contact of the fixing belt 21) is formed into a planar shape.

[0059] Here, as Figure 4 As shown, in this embodiment, the sliding contact surface 26b2 of the steam chamber 26b, which slides in contact with the fixing belt 21, is formed of a low-friction material. Specifically, a thin film coating 26x made of a low-friction material such as fluororesin is formed on the sliding contact surface 26b2 of the steam chamber 26b. With this configuration, the frictional resistance generated by the sliding contact between the fixing belt 21 and the steam chamber 26b is reduced, thereby mitigating wear and deterioration of the fixing belt 21 and the steam chamber 26b. Furthermore, to achieve the above effect, it is sufficient that only the portion formed of the low-friction material is used as the sliding contact surface 26b2; however, other portions can also be formed of a low-friction material.

[0060] Here, as Figure 4 and Figure 5 As shown, in this embodiment, in the steam chamber 26b, within the hollow portion 26b1 containing the working fluid, a columnar member 26b10 is provided between the inner wall surface 26b4 of the clamping portion on the clamping portion side and the inner wall surface 26b5 (the inner wall surface on the reinforcing member 23 side) of the non-clamping portion facing the inner wall surface 26b4 of the clamping portion. That is, the hollow portion 26b1 of the steam chamber 26b is not only a space for the flow of the working fluid, but also provides multiple columnar members 26b10 from the clamping side to the non-clamping side, within a range that does not impede heat exchange achieved by the flow of the working fluid. Furthermore, in this embodiment, the columnar members 26b10 are integrally formed from the same material as the frame of the steam chamber 26b. By providing the columnar members 26b10 in this way, even when pressure from the pressure roller 31 is applied to the steam chamber 26b, which has insufficient mechanical strength due to the presence of the hollow portion 26b1, deformation is less likely. Therefore, it is easy to maintain the desired shape of the clamping part, to stably perform a good fixing process, and to easily maintain the good heat exchange properties of the steam chamber 26b.

[0061] For example, Figure 6The fuser shown is an example where the clamping forming member 26 uses a heat pipe. Because the heat pipe has good thermal conductivity, during preheating, the heat of the fuser member is taken away by the clamping forming member 26, and the heat escapes to the member holding the clamping forming member 26.

[0062] For example, Figure 7 The fuser assembly shown has a structure in which the clamping forming member 26 is made of metal and is provided with a portion that allows the support bar (reinforcing member 23) and the clamping forming member 26 to be thermally separated, thereby improving the temperature rise at the end. During preheating, although the configuration is designed to cut off the thermal contact separation portion, the portion holding the clamping forming member 26 is in contact with other components, so the heat of the fuser belt 21 is taken away by the clamping forming member 26, while the heat escapes to the component holding the clamping forming member 26.

[0063] For example, Figure 8 (Overall cross-sectional view of fixing device 20) and Figure 9 The fixing device 20 shown in the partial cross-sectional view of the fixing device 20 is an example in which a vapor chamber 26b is used in the clamping forming member 26. Because the vapor chamber 26b has good thermal conductivity, the heat of the fixing belt 21 is taken away by the clamping forming member 26 during preheating, while the heat escapes to the member holding the clamping forming member 26.

[0064] Figure 10 The fixing device 20 shown is Figure 8 and Figure 9 The example shown is an improvement to the fixing device 20. Its purpose is to reduce the contact area by making the contact portion of the holding part 26a of the holding vapor chamber 26b from a flat surface to a concave-convex shape, thereby suppressing heat escape. However, the effect is insufficient; during preheating, the heat of the fixing belt 21 is taken away by the clamping forming member 26, and heat escapes to the components of the clamping forming member 26.

[0065] Figure 11 The fixing device 20 shown is with Figure 8 The same example, but with a different opening direction for heater 25. The following is based on... Figure 11 This embodiment will now be described. Furthermore, this embodiment can also be applied to… Figure 8 The fixing device 20 is shown in the figure.

[0066] Figure 12 This is a cross-sectional view of an example of the fixing apparatus of this embodiment. In this embodiment, as... Figure 12As shown, a transfer portion 26b1 is provided between the steam chamber 26b and the reflector 27, thereby bringing the components into contact. That is, the transfer portion 26b1 is an example of a heat conduction component that brings the steam chamber 26b into contact with the reflector 27. Before the preheating operation, all components of the fixing device 20 are at room temperature. When the preheating operation begins, a driving force is applied to the pressure roller 31, and the pressure roller 31 and the fixing belt 21 rotate in conjunction at a predetermined speed. At the same time, the heating element (heater 25) is energized and heated, and the inner circumferential surface of the fixing roller 21 receives heat from the heater 25 and heat reflected by the reflector 27 while rotating, thereby heating the entire circumference and raising it to the target temperature. At this time, since the heat is taken away by the clamping forming member 26 in contact with the inner circumference and the pressure roller 31 in contact with the outer circumference, the temperature rise rate of the fixing belt 21 is also slowed down.

[0067] In this embodiment, during the preheating operation, the heat lost by the clamping forming member 26 in contact with the inner periphery is reduced. The surface of the reflector 27 has a surface property that easily reflects the light and heat of the heater 25, but because it is subjected to heat from the heater 25 at close range, the temperature of the reflector 27 itself rises more rapidly than that of the surrounding members, even during preheating. In the prior art, the heat applied to the reflector 27 is dissipated naturally inside the fixing belt 21 or through members in contact with the support member 23, etc. In this embodiment, by bringing the reflector 27 into contact with the steam chamber 26b at the heat transfer portion 26b1, the heat applied to the reflector 27 is moved to the steam chamber 26b. Because the heat transfer portion 26b1 and the steam chamber 26b have good thermal conductivity, the heat applied to the reflector 27 is rapidly and uniformly transferred to the steam chamber 26b. As a result, although the heat of the fixing belt 21 was previously taken away by the steam chamber 26b during preheating, the steam chamber 26b quickly becomes high temperature due to the heat from the reflector 27. Therefore, the heat movement of the fixing belt 21 is reduced, and as a result, the fixing belt 21 quickly reaches the specified temperature, which can shorten the preheating time.

[0068] Figure 13 and Figure 14 This is a diagram illustrating an example of the fixing apparatus of this embodiment. Figure 13 yes Figure 12 A perspective view of an example of the steam chamber 26b and the transfer portion 26b1 in a cross-sectional view of the fixing device 20 shown. Figure 13 In the example shown, an L-shaped bend is provided on the lower side of the steam chamber 26b. The front end extending from the root of the L-bend along the horizontal direction of the figure corresponds to... Figure 12 The transfer portion 26b1 is shown. Although its front end is omitted from the diagram, it is configured to contact the reflector 27. That is, the transfer portion 26b1 is an example of a heat conduction component integrally formed with the clamping forming member 26.

[0069] Figure 14 This is a cross-sectional view of an example of the steam chamber 26b and the transfer portion 26b1. Since the steam chamber 26b and the transfer portion 26b1 are integrally formed, the hollow portion of the steam chamber 26b containing the working fluid is connected to the hollow portion of the transfer portion 26b1. As a result, the contact portion of the transfer portion 26b1 with the reflector 27 is constructed from a high thermal conductivity component containing the working fluid. Because the steam chamber 26b and the reflector 27 are in thermal contact at the transfer portion 26b1, which has high thermal conductivity, it is possible to shorten the preheating time of the fixing device 20 and improve energy efficiency. Furthermore, in Figure 13 In the example shown, there are three transmission points 26b1, but as long as they are in contact with the reflector 27, their number, width, and position can be arbitrarily configured.

[0070] Figures 15-18 This is a diagram illustrating an example of the fixing apparatus of this embodiment. (As shown...) Figure 18 As shown in the schematic perspective view, a transfer member 28 can be provided that is separate from the steam chamber 26b. That is, the transfer member 28 is an example of a heat conduction member that brings the steam chamber 26b into contact with the reflector 27, and is formed separately from the clamping forming member 26. Figure 15 Is with Figure 12 The example shown illustrates a similar arrangement of the transfer member 28 on the side of the steam chamber 26b, with the transfer portion 26b1 also positioned there. The effect is the same, but by making the steam chamber 26b and the transfer member 28 separate components, the steam chamber 26b does not require bending or complex shapes, thus simplifying manufacturing. Furthermore, by simplifying the shape of the steam chamber 26b, improvements in thermal conductivity, increased part production efficiency, and reduced part manufacturing costs can be expected. However, since there are additional requirements regarding the mechanism for mounting the transfer member 28 and the fixing method, it is sufficient to select the method most suitable for the mounting fixing device 20.

[0071] Figure 16 This example involves the heat transfer member 28 abutting against the back side plane of the clamping surface of the steam chamber 26b, and then contacting the reflector 27 at a relative position. Because the steam chamber 26b has good thermal conductivity, heat is immediately distributed throughout the entire chamber regardless of where the heat transfer member 28 is placed, thus achieving the same heat transfer effect. To position the heat transfer member 28 and ensure thermal contact between the steam chamber 26b and the reflector 27, openings are partially provided in the holding part 26a and the support member 23. This ensures the path of the heat transfer member 28 while preventing heat loss through contact with it. Furthermore, when contact with other components is unavoidable to maintain the heat transfer member 28, a material or form that provides high thermal insulation and does not absorb heat is preferred.

[0072] Figure 17 Also with Figure 16The same diagram is shown, but with a different opening direction for the reflector 27. The transfer member 28 is preferably made of a material with good thermal conductivity and heat resistance; common metal materials include copper alloys and aluminum. Alternatively, the transfer member 28 may be a machined product partially disposed between the clamping forming member 26 and the reflector 27.

[0073] Figure 18 This is a schematic perspective view illustrating an example of the fixing device of this embodiment. Figure 18 As shown, a transfer component 28, separate from the steam chamber 26b, can also be provided. For optimal results, it is preferable that the transfer component 28 itself has high thermal conductivity. In the steam chamber 26b, even better results can be obtained by using a steam chamber or heat pipe, etc., constructed from a hollow internal component sealed with working fluid. Figure 18 The schematic diagram of the plate-shaped transfer component 28 represents a vapor chamber, and the schematic diagram of the cylindrical shape represents a heat pipe. That is, the transfer part 26b1 is an example of a vapor chamber 26b containing a highly thermally conductive material sealed with a working fluid (working agent) or a heat conduction component of a heat pipe.

[0074] like Figure 13 , Figure 18 , Figure 19 , Figure 20 As shown in the schematic perspective view, as long as the reflector 27 and the steam chamber 26b are in contact with each other, the number, width and position of the transmission part 26b1 and the transmission component 28 can be arbitrarily configured. Figure 19 The transmission portion 26b1 shown is an example in which the steam chamber 26b is integrally configured at both ends of the sheet P in the width direction. Figure 20 The transmission part 26b1 shown is an example in which the steam chamber 26b is integrally configured on both the upstream and downstream sides of the sheet P in the conveying direction.

[0075] Regardless of the type, due to the good thermal conductivity of the transfer portion 26b1 or heat transfer component 28 integrally formed with the steam chamber 26b, rapid homogenization of the entire structure is achieved, thus a homogenization effect is obtained by partially exposing any part to heat. As a result, the preheating time of the fixing device 20 can be shortened and energy-saving effects improved. Alternatively, the steam chamber 26b and the reflector 27 can be in thermal contact across the entire width of the sheet P, in which case an even faster homogenization effect can be obtained. That is, the transfer portion 26b1 is an example of a heat conduction component partially provided between the clamping forming member 26 and the reflector 27.

[0076] like Figure 19As shown in the schematic perspective view, the transfer parts 26b1 are respectively arranged on the upstream and downstream sides of the sheet P in the conveying direction. By arranging the transfer parts 26b1 upstream and downstream of the sheet P, the steam chamber 26b in the conveying direction of the sheet P can be positioned by means of the clamping and holding part 26a. At this time, it is preferable to provide a component with high heat insulation at the contact portion between the transfer part 26b1 and the holding part 26a to prevent heat leakage.

[0077] Figure 19 The number of transfer points 26b1 in the upstream and downstream directions and the width direction of sheet P is arbitrary, but through methods such as... Figure 19 By configuring the transfer parts 26b1 near both ends of the steam chamber 26b in the width direction, the positioning becomes stable. For example... Figure 20 As shown in the schematic perspective view, the transfer parts 26b1 are respectively arranged in the width direction of the sheet P. Figure 19 The right and left sides of the sheet P. By providing transfer portions 26b1 at both ends in the width direction of the sheet P, it is possible to position the vapor chamber 26b in the width direction of the sheet P by using clamping and holding portions 26a. In this case, it is preferable to provide a heat-insulating component at the contact portion between the transfer portion 26b1 and the holding portion 26a to prevent heat leakage. That is, the transfer portion 26b1 is an example of a heat-conducting component having a positioning portion of the clamping forming component 26.

[0078] Thus, according to this embodiment, even when the steam chamber 26b with high thermal conductivity is used to hold the forming member 26, the heat of the fixing belt 21 will not be taken away by effectively utilizing the heat of the reflector 27, thereby shortening the start-up time of the fixing device 20 and improving the energy-saving effect.

[0079] Furthermore, in this embodiment, the present invention is applied to a fixing apparatus 20 that uses a pressure roller 31 as a pressure rotating body, but the present invention can also be applied to a fixing apparatus that uses a pressure belt as a pressure rotating body. Then, even in that case, the same effect as in this embodiment can be obtained.

[0080] Furthermore, this invention is not limited to this embodiment. Within the scope of the technical concept of this invention, it is obvious that appropriate modifications can be made to this embodiment beyond what is taught in this embodiment. In addition, the number, position, shape, etc., of the constituent components are not limited to this embodiment, and suitable numbers, positions, shapes, etc., can be selected when implementing this invention.

[0081] Furthermore, in this application specification, the definition of "width direction" is a direction orthogonal to the transport direction of the recording medium P, which is the same as the rotation axis direction of the fixing belt 21 or the pressure roller 31.

[0082] Furthermore, in the above embodiments, an example was given of applying the image forming apparatus of the present invention to a multifunctional peripheral device having at least two of the following functions: copying, printing, scanning, and faxing. However, it can also be applied to any of the image forming apparatuses such as copiers, printers, scanners, and faxing devices.

[0083] Examples of embodiments of the present invention are described below.

[0084] <1>

[0085] A fixing device, characterized in that it comprises: an annular fixing belt rotatable; a pressure roller opposite to the fixing belt and configured to be rotatable; a heater disposed inside the fixing belt and heating the fixing belt; a clamping forming member disposed inside the fixing belt and including a steam chamber opposite to the pressure roller to form a clamping portion; a reinforcing member disposed inside the fixing belt and supporting the clamping forming member; and a reflector disposed between the heater and the reinforcing member to reflect heat from the heater toward the fixing belt, wherein the steam chamber included in the clamping forming member is in contact with the reflector through a heat conduction member.

[0086] <2>

[0087] according to <1> The fixing device is characterized in that: the heat conduction component and the clamping forming component are integrally formed.

[0088] <3>

[0089] according to <1> The fixing device is characterized in that the heat conduction component and the clamping forming component are formed separately.

[0090] <4>

[0091] according to <3> The fixing device is characterized in that: the heat conduction component includes a vapor chamber or heat pipe containing a high thermal conductivity material with a working agent.

[0092] <5>

[0093] according to <1> to <4> The fixing device according to any one of the following methods, characterized in that: the heat conduction component is partially disposed between the clamping forming component and the reflector.

[0094] <6>

[0095] according to <2> The fixing device is characterized in that: the heat conduction component has a positioning part of the clamping forming component.

[0096] <7>

[0097] An image forming apparatus, characterized in that: it comprises <1> to <6> The fixing device as described in any one of the following.

Claims

1. A fixing device characterized by include: The fixing band is ring-shaped and can rotate; A pressure roller, which is opposite the fixing belt and is configured to be rotatable; A heater is disposed inside the fixing belt and heats the fixing belt; A clamping forming component is disposed inside the fixing belt and includes a steam chamber that forms a clamping portion opposite to the pressure roller; A reinforcing member, disposed inside the fixing belt, supports the clamping forming member, and A reflector, disposed between the heater and the reinforcing member, reflects heat from the heater toward the fixing belt. The steam cavity included in the clamping forming component is in contact with the reflector through a heat conduction component.

2. The fixing device according to claim 1, characterized in that: The heat conduction component is integrally formed with the clamping forming component.

3. The fixing device according to claim 1, characterized in that: The heat conduction component and the clamping forming component are formed separately.

4. The fixing device according to claim 3, characterized in that... : The heat conduction component includes a vapor chamber or heat pipe containing a highly thermally conductive material encapsulated with a working agent.

5. The fixing device according to any one of claims 1 to 4, characterized in that... : The heat-conducting component is partially disposed between the clamping forming component and the reflector.

6. The fixing device according to claim 2, characterized in that: The heat conduction component includes the positioning portion of the clamping forming component.

7. An image forming apparatus, characterized in that: The fixing device is provided with any one of claims 1 to 4.

Images