Heating device, pressure treatment device using the same, and image forming device

Abstract

To provide a heating device that includes heat generating means using a heat pipe, and can protect a sealing part of the heat pipe.SOLUTION: A heating device 1 comprises: heat generating means 2 that has a heat generating unit 2a generating heat along a longitudinal direction and heats a body to be heated 10; a heat pipe 3 that is in contact with the heat generating means 2 and extends along a longitudinal direction of the heating unit 2a; and holding means 4 that holds the heat pipe 3. The holding means 4 has a storage reception unit 5 that stores the heat pipe 3, and a protective member 6 that holds an end on the side of the sealing part 3a of the heat pipe 3 and an end of the storage reception unit 5 in a non-contact manner with a space part therebetween. The present invention is also applied to a heat treatment device using the heating device 1, and an image forming apparatus using the heat treatment device as a fixing device.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a heating device equipped with a heat generating means that utilizes a heat pipe, and a pressure processing device and an image forming apparatus that use the same. [Background technology]

[0002] A conventional heating device of this type is disclosed in Patent Document 1, for example. Patent document 1 discloses an image forming device that uses a heater in which a heating element is printed on the surface of a low-heat-capacity plate-shaped heat pipe via an insulating layer, thereby suppressing temperature rise in non-paper-passing areas and shortening start-up time. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2013-142834 A (Mode for carrying out the invention, Figure 1) Summary of the Invention [Problem to be solved by the invention]

[0004] The technical problem to be solved by the present invention is to provide a heating device that includes a heat generating means that utilizes a heat pipe and that is capable of protecting the sealed portion of the heat pipe. [Means for solving the problem]

[0005] A first technical feature of the present invention is a heat generating device having a heat generating portion that generates heat along the longitudinal direction and heats an object to be heated, a heat pipe that contacts the heat generating portion or the object to be heated and extends along the longitudinal direction of the heat generating portion, and a holding portion that holds the heat pipe, wherein the holding portion has a receiving portion that receives the heat pipe, and a protective component that keeps the end of the heat pipe on the sealing portion side and the end of the receiving portion in a non-contact state via a space. It is a heating device.

[0006] A second technical feature of the present invention is a heating device having the first technical feature, characterized in that the protective component is an elastic member that is elastically deformable along the longitudinal direction of the heat pipe. A third technical feature of the present invention is a heating device having the second technical feature, characterized in that the protective component is a compression coil spring having an inner diameter smaller than the outer diameter of the heat pipe and elastically deformable along the longitudinal direction of the heat pipe. A fourth technical feature of the present invention is a heating device having the third technical feature, characterized in that the protective component is the compression coil spring having a tightly fitted length longer than the dimension of the longitudinal protrusion of the sealed portion of the heat pipe in the region where the protective component is attached. A fifth technical feature of the present invention is the heating device having the first technical feature, characterized in that the protective component is a non-elastic member. A sixth technical feature of the present invention is a heating device having the fifth technical feature, characterized in that the heating device is a cylindrical member having an inner diameter smaller than the outer diameter of the heat pipe and surrounding the end of the heat pipe on the sealing portion side. A seventh technical feature of the present invention is a heating device having the sixth technical feature, characterized in that the protective part is a cylindrical member having an axial length longer than the dimension of the longitudinal protrusion of the sealed portion of the heat pipe in the area where the protective part is attached. An eighth technical feature of the present invention is a heating device having the first technical feature, characterized in that an elastic member is interposed between the end of the accommodating portion and the end of the heat pipe opposite the sealing portion.

[0007] A ninth technical feature of the present invention is a heat treatment apparatus comprising: a rotating belt-shaped heated object; a heating device having the first technical feature that is provided within the heated object; and a pressure means that rotates in contact with a portion of the heated object facing the heat generation means and applies pressure to the object to be heat-treated. A tenth technical feature of the present invention is an image forming apparatus comprising a fixing means for fixing an unfixed image on a medium by heating and pressurizing the medium on which the unfixed image is held, and an image forming means for forming the unfixed image on the medium, wherein the fixing means uses a heat treatment device having the ninth technical feature. [Effects of the Invention]

[0008] According to a first technical feature of the present invention, it is possible to provide a heating device that includes heat generating means that utilizes a heat pipe and that is capable of protecting the sealed portion of the heat pipe. According to the second technical feature of the present invention, a single protective component can allow for thermal expansion and deformation of the heat pipe and also protect the sealed portion of the heat pipe. According to the third technical feature of the present invention, a protection component having elasticity can be easily configured by using a compression coil spring. According to the fourth technical feature of the present invention, when a compression coil spring is used to form an elastic protective component, the end of the heat pipe on the sealing portion side can be reliably protected from damage. According to the fifth technical feature of the present invention, even if the protective component is made of a non-elastic material, it is possible to protect the sealed portion of the heat pipe. According to a sixth technical feature of the present invention, a non-elastic protective component can be easily constructed using a cylindrical member. According to the seventh technical feature of the present invention, when a cylindrical member is used to form an inelastic protective component, the end of the heat pipe on the sealing portion side can be reliably protected from damage. According to the eighth technical feature of the present invention, the protective component, whether elastic or inelastic, can tolerate the thermal expansion and deformation of the heat pipe, and can also protect the ends of the heat pipe other than the sealed portion against impacts such as when dropped. According to a ninth technical feature of the present invention, it is possible to provide a heat treatment apparatus including a heating device that is equipped with heat generating means that utilizes a heat pipe and that can protect the sealed portion of the heat pipe. According to a tenth technical feature of the present invention, an image forming apparatus can be provided in which a fixing means for fixing an unfixed image is provided with a heat generating means using a heat pipe, and a heat treatment apparatus including a heating device capable of protecting a sealed portion of the heat pipe is used, thereby uniformly heating and fixing an unfixed image. [Brief explanation of the drawings]

[0009] [Figure 1] 1A is an explanatory diagram showing an outline of an embodiment of a heat treatment apparatus including a heating device to which the present invention is applied; FIG. 1B is an arrow view of the main part of the heating device shown in FIG. 1A, turned upside down and viewed from the direction of arrow B; FIG. 1C is an enlarged view of part C in FIG. 1B; and FIG. 1D is an enlarged view of part D in FIG. 1B. [Figure 2] 1 is an explanatory diagram showing the overall configuration of an image forming apparatus according to a first embodiment. [Figure 3] 3A is an explanatory diagram showing an example of a fixing device as the heat treatment device shown in FIG. 2, and FIG. 3B is an explanatory diagram showing an example of the configuration of a heat pipe in FIG. [Figure 4] FIG. 3(a) is an explanatory diagram showing an example of a holding structure for a heat pipe of a heating device used in the fixing device shown in FIG. 3(a), FIG. 3(b) is an enlarged view of part B in FIG. 3(a), and FIG. 3(c) is an enlarged view of part C in FIG. [Figure 5] (a) is an explanatory diagram showing details of the holding structure at the end of the heat pipe on the sealing side shown in Figure 4(c), (b) is an explanatory diagram showing each parameter when the compression coil spring as a protective part is in an extended state, (c) is an explanatory diagram showing parameters when the compression coil spring as a protective part is in maximum compression, and (d) is an explanatory diagram showing details of the holding structure at the opposite end of the heat pipe shown in Figure 4(b). [Figure 6] 1(a) is an explanatory diagram showing an example of a holding structure for a heat pipe of a heating device according to comparative embodiment 1, (b) is an enlarged view of part B in (a), and (c) is an enlarged view of part C in (a). [Figure 7] 1(a) is an explanatory diagram showing an example of a holding structure for a heat pipe of a heating device according to a first modified embodiment, and FIG. 1(b) is an explanatory diagram showing an example of a holding structure for a heat pipe of a heating device according to a second modified embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Overview of the implementation form FIG. 1(a) is an explanatory diagram showing an outline of an embodiment of a heat treatment apparatus using a heating device to which the present invention is applied. In the same figure, the heat treatment device comprises a rotating belt-shaped heated object 10, a heating device 1 installed inside the heated object 10, and a pressure means 11 that rotates in contact with the part facing the heating device 1 across the heated object 10 and applies pressure to the object to be heat-treated 12. Here, either the object to be heated 10 or the pressurizing means 11 may be rotated while the other is rotated by the rotation of the object to be heated 10 or the pressurizing means 11. In this example, as shown in Figures 1(a), (b) and (d), the heating device 1 has a heat generating portion 2a that generates heat along the longitudinal direction and is equipped with a heat generating means 2 that heats the heated object 10, a heat pipe 3 that contacts the heat generating means 2 and extends along the longitudinal direction of the heat generating portion 2a, and a holding means 4 that holds the heat pipe 3, and the holding means 4 has a receiving portion 5 that receives the heat pipe 3, and a protective part 6 that keeps the end of the heat pipe 3 on the sealing portion 3a side and the end of the receiving portion 5 non-contact with each other via a space. In this example, the holding means 4 has a receiving portion 5 for holding the heat generating means 2, but this is not limited to this, and it goes without saying that the heat generating means 2 may be held by a dedicated holding means separate from the holding means 4. Also, in the example shown in Fig. 1, the heat pipe 3 is in direct contact with the heat generating means 2, but instead, it may be in direct contact with the object 10 to be heated.

[0011] In such technical means, the heat generating means 2 is not limited to a planar heat generating means, but broadly includes those having a heat generating portion 2a. The cross-sectional shape of the heat pipe 3 is not particularly limited, but a circular cross-section is preferable from the viewpoint of strength. In this example, the heat pipe 3 is constructed by incorporating a working fluid and a capillary structure (a so-called wick) into a pipe member with one open end, and then crimping and welding the open end of the pipe member. For this reason, the end of the heat pipe 3 on the sealed portion 3a side is prone to breakage due to impact, for example, when the heating device 1 is dropped, and care must be taken. Furthermore, the holding means 4 may include a receiving portion 5 for the heat pipe 3 and a protective part 6. The protective part 6 may be a part that prevents the end of the heat pipe 3 on the sealed portion 3a side from colliding with the end of the receiving portion 5 and being damaged when the heating device 1 is dropped, and may at least keep the end of the receiving portion 5 and the end of the sealed portion 3a of the heat pipe 3 out of contact with each other via a space. The requirement of "keeping them out of contact with each other via a space" is intended to avoid the possibility that an impact from the end of the receiving portion 5 would be directly transmitted via the spacer that contacts the sealed portion 3a of the heat pipe 3 if a spacer were simply interposed between the end of the sealed portion 3a of the heat pipe 3 and the end of the receiving portion 5.

[0012] Next, a typical or preferred embodiment of this embodiment will be described. First, a typical embodiment of the protective component 6 is an elastic member that is elastically deformable along the longitudinal direction of the heat pipe 3. This embodiment is preferable because the protective component 6 is made of an elastic member, which makes it possible to absorb the amount of deformation even if the heat pipe 3 undergoes thermal expansion and deformation. In this example, a preferred embodiment of the protective component 6 is a compression coil spring that has an inner diameter smaller than the outer diameter of the heat pipe 3 and is elastically deformable along the longitudinal direction of the heat pipe 3. In this case, in order to position the end of the sealed portion 3a of the heat pipe 3 in a non-contact manner with the end of the receiving portion 5 even when the compression coil spring is compressed and deformed, it is preferable that the compression coil spring have a contact length that is longer than the dimension of the longitudinal protrusion of the sealed portion 3a of the heat pipe 3 in the region where the protective component 6 is attached.

[0013] Another typical embodiment of the protective part 6 is an inelastic member. In this example, as long as the protective part 6 is a cylindrical member having an inner diameter smaller than the outer diameter of the heat pipe 3 and surrounding the end of the heat pipe 3 on the sealed portion 3a side, it is possible to keep the end of the sealed portion 3a of the heat pipe 3 and the end of the receiving portion 5 out of contact with each other via a space. In this case, it is preferable that the cylindrical member have an axial length longer than the dimension of the longitudinal protrusion of the sealed portion 3a of the heat pipe 3 in the region where the protective part 6 is attached.

[0014] 1(b) and 1(c), a preferred embodiment of the holding means 4 is one in which an elastic part 7 is interposed between the end of the receiving portion 5 and the end of the heat pipe 3 opposite the sealed portion 3a. In this embodiment, both ends of the heat pipe 3 are held at the ends of the receiving portion 5 by the protective part 6 and the elastic part 7, so that both ends of the heat pipe 3 do not directly collide with the ends of the receiving portion 5. If the protective part 6 is elastic, the heat pipe 3 is elastically held at both ends. Furthermore, even if the protective part 6 is inelastic, the elasticity of the elastic part 7 effectively absorbs the thermal expansion and deformation of the heat pipe 3.

[0015] The present invention will be described in more detail below based on the embodiments shown in the accompanying drawings. Embodiment 1 -Overall configuration of image forming device- FIG. 2 is an explanatory diagram showing the overall configuration of the image forming apparatus according to the first embodiment. In the figure, the image forming apparatus 20 is a so-called tandem-type image forming apparatus using an intermediate transfer method. It has multiple image forming stations 22 (22a-22d) where toner images of each color component (four colors: yellow (Y), magenta (M), cyan (C), and black (K) in this example) are formed by electrophotography. A belt-shaped intermediate transfer body 23 is disposed at a location corresponding to each image forming station 22, and a primary transfer device 24 (a primary transfer roll in this example) is disposed behind the intermediate transfer body 23 corresponding to each image forming station 22. Furthermore, a secondary transfer device (a secondary transfer roll in this example) 25 is disposed at a portion of the intermediate transfer body 23. The primary transfer device 24 transfers each color component toner image from each image forming station 22 to the intermediate transfer body 23, and the secondary transfer device 25 transfers the color component toner image, which has been primarily transferred from each image forming station 22 to the intermediate transfer body 23 by the primary transfer device 24, onto a medium S such as paper. A fixing device 60 is disposed downstream in the transport direction of the medium S onto which the color component toner image has been transferred, to fix any unfixed toner images on the medium S. In this example, the plurality of image forming units 22, the intermediate transfer body 23, the primary transfer device 24, and the secondary transfer device 25 correspond to an image forming unit that forms an unfixed image on a medium.

[0016] Here, each image forming unit 22 has a drum-shaped photosensitive member 30 that rotates in a predetermined direction, and is surrounded by a charging device 31 that charges the photosensitive member 30, an exposure device 32 such as a laser scanning device that writes an electrostatic latent image on the photosensitive member 30 charged by the charging device 31, a developing device 33 that develops the electrostatic latent image written on the photosensitive member 30 by the exposure device 32 with a corresponding color toner, and a cleaning device 34 that cleans off any residue on the photosensitive member 30 after the toner image developed by the developing device 33 has been primarily transferred onto the intermediate transfer member 23 by the primary transfer device 24. The intermediate transfer body 23 is stretched over a plurality of tension rolls 41 to 45, and is configured to rotate cyclically in a predetermined direction, for example, with the tension roll 41 as a drive roll. The tension roll 44 also serves as an opposing roll to the secondary transfer roll of the secondary transfer device 25, and generates a secondary transfer electric field required for secondary transfer between the secondary transfer roll and the opposing roll. Furthermore, an intermediate transfer cleaning device 46 is disposed on the surface of the intermediate transfer body 23 corresponding to the tension roll 45.

[0017] Furthermore, a medium supply device 50 is provided below the intermediate transfer body 23, and the medium S supplied from this medium supply device 50 is transported along a transport path 51 that passes through a secondary transfer device 25 and reaches a fixing device 60. The transport path 51 is further provided with an appropriate number of transport rolls 52, a transport belt 53 that transports the medium S from the secondary transfer device 25 to the fixing device 60, guide plates 54 and 55 that guide the medium S to the secondary transfer portion by the secondary transfer device 25 and the fixing portion of the fixing device 60, and discharge rolls 56 that discharge the medium S to a medium discharge portion not shown.

[0018] -Fixing device- Next, the fixing device 60 used in this embodiment will be described with reference to FIGS. In the same figure, the fixing device 60 has the width dimension required to fix the medium S moving in the conveying direction, and is equipped with a fixing belt 61 as a heated body that moves in a circulating manner, a heating device 62 that is provided in contact with the back side of the fixing belt 61 and heats the fixing belt 61, and a pressure roll 63 as a pressure means that rotates in contact with the part opposite the heating device 62 across the fixing belt 61 and pressurizes the medium S on which an unfixed image is held in the fixing area (contact area) FP. The fixing belt 61 is an endless heat-conducting belt that is flexible and heat-resistant. The fixing belt 61 is made of a material such as a synthetic resin, such as polyimide or polyamide, and is formed into a cylindrical shape.

[0019] The pressure roll 63 has an elastic layer, a release layer, etc., provided on the outer peripheral surface of a columnar or cylindrical roll base 63a made of, for example, metal, etc. The pressure roll 63 has shaft portions 63b rotatably supported at both axial ends by bearings (not shown), and is pressed toward the heating device 62 by a pressure mechanism (not shown). Furthermore, in this example, the pressure roll 63 receives a driving force from a driving source (not shown) via a drive transmission mechanism (not shown), and is driven to rotate when necessary for an image forming operation, etc., and accordingly the fixing belt 61 rotates following the pressure roll 63. Of course, it is also possible to drive the fixing belt 61 to rotate, and have the pressure roll 63 rotate following the rotation.

[0020] -Heating device- In this example, the heating device 62 is a device that heats, via the fixing belt 61, the medium S that is sandwiched between the fixing belt 61 and the pressure roll 63 and conveyed under pressure. Furthermore, in this heating device 62, when media S with a width dimension smaller than the maximum size are passed continuously through the fixing area FP, an area (non-media passing area) will be created in the fixing area FP where the media S does not pass, and since heat is not taken away by the passing media S in this non-media passing area, the non-media passing area in the fixing area FP will become locally hotter than the media passing area, and as a result, there is a concern that the fixing temperature distribution in the fixing area FP will be uneven in the width direction. In this example, in order to suppress unnecessary temperature increases in the non-media passing area of ​​the fixing area FP, the heating device 62 is arranged on the back side of the fixing belt 61 corresponding to the fixing area FP, and is equipped with a planar heater 70 as a long heat generating means extending in a width direction intersecting the transport direction of the medium S, a heat pipe 80 extending in the longitudinal direction of the planar heater 70 and arranged in contact with the back side of the planar heater 70, and a holder 90 that holds the planar heater 70 and the heat pipe 80.

[0021] -Surface heater- In this example, the planar heater 70 has a substrate 71, a heat generating portion 72 provided on the surface of the substrate 71 that comes into contact with the inner surface of the fixing belt 61, and a wiring portion not shown for supplying power to the heat generating portion 72. Here, the substrate 71 is a rectangular plate-like member whose length dimension in the width direction intersecting the transport direction of the medium S is longer than the maximum size. The substrate 71 is made of an electrically insulating material, and for example, a ceramic substrate is used. The heat generating portion 72 is an electric heating wire portion consisting of a heating resistor arranged in a straight line along the longitudinal direction on one side of the substrate 71, and although only one is shown in the figure, it is usually composed of multiple (e.g., three) electric heating wire portions spaced apart from each other, with areas that generate relatively more heat being located at different positions to accommodate differences in width dimension when the medium S is transported.

[0022] -Heat pipe- In this example, two heat pipes 80 are arranged in contact with both sides of the surface (back surface) of the planar heater 70 opposite to the surface that contacts the fixing belt 61 along the longitudinal direction. As shown in Figure 3(b), the heat pipes 80 (specifically, 80a and 80b) are both sealed tubes 81 made of a material with excellent thermal conductivity such as copper or stainless steel, with both ends of the cylinder closed, and the inner wall of the sealed tube 81 has a capillary structure (a so-called wick) 82, and a volatile working fluid (pure water or the like) 83 is sealed inside the sealed tube 81. The heat pipes 80 (80a and 80b) have approximately the same length as the heat generating part 72 of the planar heater 70, and since two of them are used arranged in parallel, those with a relatively small diameter (for example, an outer diameter of a few millimeters) are used.

[0023] In this example, the sealed tube 81 uses a pipe member 85 with a bottom and an open end, the inner wall of which is formed into a capillary structure 82, and after the working fluid 83 flows in through the opening at one end, the opening at one end of the pipe member 85 is sealed with a crimped portion 86 as a sealing portion. Here, the crimped portion 86 is a portion that has undergone processing, for example, by crushing the end of the pipe member 85 in a vacuum and sealing it in a joined state, and is a portion that is thinner and weaker than the outer diameter portion of the normal pipe member 85 other than the crimped portion 86. This crimped portion 86 has a tip end with a smaller diameter than the outer diameter portion of the normal pipe member 85, and is configured as a protrusion that protrudes from the end of the normal pipe member 85, but the external shape of the crimped portion 86 is not particularly limited. Note that in this example, an example is shown in which the crimped portion 86 is used as a sealing portion, but it goes without saying that the sealing portion may be one that has been subjected to a joining process such as welding.

[0024] -Holder- In this example, as shown in Figures 3(a) and 4, the holder 90 has a holder main body 91 in which the planar heater 70 is held, and this holder main body 91 is formed with a heat pipe holding portion 95 as a holding means for holding the heat pipe 80, as well as a guide portion 105 that guides the movement trajectory of the fixing belt 61, and the holder main body 91 is fixed to a support bracket 110 for mounting. <Holder body> In this example, the holder main body 91 is formed integrally and elongated along the width direction of the medium S from a heat-resistant material (for example, a heat-resistant resin such as LCP, PPS, or PET), and has an accommodating recess 92 for accommodating the planar heater 70 on the surface facing the fixing belt 61. This accommodating recess 92 is formed in an elongated rectangular shape that is approximately the same as the cross-sectional shape of the planar heater 70, and has a depth dimension that is slightly shallower than the thickness dimension of the planar heater 70, so that when the planar heater 70 is accommodated, the surface of the planar heater 70 protrudes slightly from the surface of the holder main body 91 and comes into contact with the back surface of the fixing belt 61.

[0025] <Heat pipe holding part> In this example, a heat pipe holding portion 95 is formed on the bottom of the accommodating recess 92 at a location corresponding to the heat generation region of the heat generating portion 72 of the planar heater 70. This heat pipe holding portion 95 provides a recess 96 at the bottom of the accommodating recess 92 to be used as a storage space for the heat pipes 80 (80a, 80b), and both longitudinal side walls 97 of this recess 96 are provided with storage grooves 98 (specifically 98a, 98b) as storage receiving portions for storing both sides of the heat pipes 80 (80a, 80b). As shown in Figures 3(a) and 4(a) to (c), these storage grooves 98 are provided at intervals in the short direction of the holder main body 91 so that the heat pipes 80 (80a, 80b) are arranged in parallel.

[0026] The width of the receiving groove 98 is set to be approximately the same as the radial dimension of the heat pipe 80. Furthermore, an appropriate number of spacers 99 made of a heat-resistant material are provided integrally or separately on the bottom wall of the receiving groove 98 or the recess 96, making it possible to adjust the receiving height position of the heat pipe 80 and maintaining contact between the heat pipe 80 and the planar heater 70. Furthermore, the temperature of the non-medium passing area of ​​the planar heater 70 is often as high as around 200°C and is transferred to the heat pipe 80, which has the property of being prone to thermal expansion and deformation in the longitudinal direction. For this reason, it is necessary to ensure a required gap 100 (see FIG. 5) between the depth end of the accommodating groove 98 and the end of the heat pipe 80, taking into account the thermal expansion and deformation of the heat pipe 80.

[0027] Furthermore, in this example, since the required gap 100 is secured in the accommodating groove 98 (98a, 98b), as shown in Figures 4 and 5, a protective part 120 is interposed between the end of the heat pipe 80 on the crimped portion 86 side as the sealing portion and the depth end of the accommodating groove 98, keeping the two from contacting each other via a space, and an elastic part 130 that can be elastically deformed is interposed between the end of the heat pipe 80 opposite the crimped portion 86 and the depth end of the accommodating groove 98.

[0028] <Protective components> In this example, as shown in FIGS. 5(a) to 5(c), the protective component 120 uses a compression coil spring 121 as an elastic member that can be elastically deformed along the longitudinal direction of the heat pipe 80. This compression coil spring 121 has an inner diameter d2 that is smaller than the outer diameter d1 of the normal pipe member 85 other than the caulking portion 86 of the heat pipe 80, and the end of the compression coil spring 121 is caught in the middle of the caulking portion 86 to avoid the situation of moving over the caulking portion 86 and moving to the side of the normal pipe member 85. Also, let the free length of this compression coil spring 121 be L0, the close contact length be Lc, the compression deformation amount due to the external force P be L, and the protruding dimension of the region where the compression coil spring 121 is mounted in the caulking portion 86 of the heat pipe 80 be m. Then, the compression coil spring 121 is elastically deformed so as to satisfy Lc ≤ L ≤ L0, but it is preferable to satisfy at least the relationship m < Lc so that the tip of the caulking portion 86 does not contact the end on the depth side of the accommodation receiving groove 98.

[0029] <Elastic component> Also, as shown in FIG. 5(d), the elastic component 130 uses a compression coil spring 131 as an elastic member that can be elastically deformed along the longitudinal direction of the heat pipe 80. This compression coil spring 131 has an inner diameter d2 that is smaller than the outer diameter d1 of the normal pipe member 85 other than the caulking portion 86 of the heat pipe 80, and it may be interposed between the end on the opposite side of the caulking portion 86 of the heat pipe 80 and the end on the depth side of the accommodation receiving groove 98. In this example, the compression coil spring 131 as the elastic component 130 may use substantially the same one as the compression coil spring 121 as the protective component 120. In addition, in this example, although the compression coil spring 131 is used, as required for the protective component 120, it is not necessary to keep the end of the heat pipe 80 and the end on the depth side of the accommodation receiving groove 98 non-contact via the space portion. Therefore, as the elastic member, members having known elasticity such as a leaf spring, an elastic spacer, or rubber that contact each other may be used.

[0030] <Guide portion> 3 and 4, the guide portion 105 is integrally formed on the front and rear of the holder main body 91 in the conveying direction of the medium S, and includes an introduction guide portion 105a having a curved guide surface that guides the fixing belt 61 into the fixing area FP, and an extraction guide portion 105b having a curved guide surface that guides the fixing belt 61 in the direction of exiting the fixing area FP. The introduction guide portion 105a and the extraction guide portion 105b are arranged to sandwich the support bracket 110.

[0031] <Holder mounting structure> In this example, as shown in Figure 3(a), the support bracket 110 is a member that is longer than the longitudinal length of the planar heater 70, and is composed of a channel material with a U-shaped cross section that is arranged so that a pair of legs 111 protrude toward the holder 90 side. For this reason, in this example, an attachment groove 106 is formed on the back side of the holder main body 91, into which the tip of the leg 111 of the support bracket 110 is fitted, and the holder 90 is attached to the support bracket 110 with the tip of the leg 111 of the support bracket 110 fitted into this attachment groove 106. The longitudinal ends of the support bracket 110 are attached and fixed to attachment portions (not shown) provided on the inner wall surface of the fixing device housing (not shown), so that the heating device 62 is positioned within the fixing belt 61.

[0032] <Sensor mounting structure> In this example, the temperature of the heat generating portion 72 of the planar heater 70 is controlled by a control device not shown, but for temperature control, a temperature sensor not shown is arranged so as to contact a required location on the back surface of the substrate 71 of the planar heater 70, and the measurement information of this temperature sensor is fed back to the control device not shown. For this reason, in this example, as shown in FIG. 4(a), a sensor opening 140 is appropriately opened at the bottom of the recess 96 of the holder main body 91, and a temperature sensor (not shown) can be installed through this sensor opening 140.

[0033] - Fixing operation of the fixing device - Next, the operation of the fixing device according to this embodiment will be described. Now, in the image forming apparatus shown in Figure 2, when images are continuously formed on a medium S smaller than the maximum size, the toner images of each color component formed in the image forming section 22 (22a to 22d) are transferred collectively to the medium S by the secondary transfer device 25 via the intermediate transfer body 23, and the transferred unfixed image is retained on the medium S and reaches the fixing device 60. In this state, in the fixing device 60, the heat generating portion 72 of the planar heater 70 generates heat to heat the fixing belt 61, and the medium S on which the unfixed image is held is sandwiched and transported in the fixing zone FP between the fixing belt 61 and the pressure roll 63. As a result, the unfixed image on the medium S is fixed in the fixing zone FP while being heated and pressed.

[0034] At this time, if media S smaller than the maximum size pass through the fixing area FP continuously, a non-media passing area may be created in the fixing area FP, causing the temperature of the non-media passing area to rise. However, in this embodiment, the heat in the area corresponding to the non-media passing area of ​​the heat generating portion 72 of the planar heater 70 is transferred to the media passing area of ​​the planar heater 70, where the temperature is relatively lower than that of the non-media passing area, due to the heat transfer action of the heat pipes 80 (80a, 80b). As a result, in this fixing device 60, the temperature rise in the non-medium passing area is suppressed compared to when the heat pipe 80 is not provided. In particular, in this example, two heat pipes 80 (80a, 80b) are arranged parallel to each other with a gap in the transport direction of the medium S, so that the temperature rise in the non-media passing area is evenly and efficiently suppressed both before and after the transport direction of the medium S, compared to when a single heat pipe is arranged.

[0035] -Heat pipe protection operation- In this example, both longitudinal sides of the heat pipe 80 (80a, 80b) are accommodated in the accommodation grooves 98 of the holder 90, but the crimped portion 86 of the heat pipe 80 is elastically held by an elastic protective part 120 (specifically, a compression coil spring 121), and the end of the heat pipe 80 located opposite the crimped portion 86 is elastically held by an elastic part 130 (specifically, a compression coil spring 131). At this time, when the heat pipe 80 undergoes thermal expansion and deformation, the crimped portion 86 of the heat pipe 80 and the end portion opposite the crimped portion 86 tend to displace outward in the longitudinal direction of the heat pipe 80 due to the thermal expansion and deformation. However, displacement of the crimped portion 86 of the heat pipe 80 is absorbed by the compressive deformation of the compression coil spring 121, and even if the compression coil spring 121 is compressed and deformed up to the contact length Lc, it remains out of contact with the depth end of the accommodating groove 98 via the space. Therefore, the crimped portion 86 of the heat pipe 80 does not strongly abut against the depth end of the accommodating groove 98, and the risk of damage to the crimped portion 86 is reduced. On the other hand, displacement of the end of the heat pipe 80 located opposite the crimped portion 86 is absorbed by the compressive deformation of the compression coil spring 131 serving as the elastic component 130, and the end of the heat pipe 80 does not strongly abut against the depth end of the accommodating groove 98.

[0036] Furthermore, if the replacement fixing device 60 is accidentally dropped during transportation, there is a concern that the heat pipe 80 may move in the longitudinal direction due to the impact force of the drop. However, in this example, even if the crimped portion 86 of the heat pipe 80 attempts to move toward the depth end of the accommodating groove 98, the movement of the crimped portion 86 is elastically stopped by the compression coil spring 121, and the presence of the compression coil spring 121 keeps the crimped portion 86 out of contact with the depth end of the accommodating groove 98 via the space 150. Therefore, the crimped portion 86 of the heat pipe 80 does not strongly hit the depth end of the accommodating groove 98, and the risk of damage to the crimped portion 86 is reduced. Furthermore, even if the end of the heat pipe 80 located opposite the crimped portion 86 attempts to move toward the depth end of the accommodating groove 98, the end is elastically stopped by the compression coil spring 131, and the end of the heat pipe 80 does not strongly hit the depth end of the accommodating groove 98.

[0037] In particular, in this example, because both ends of the heat pipe 80 (80a, 80b) are elastically held by the elastic protective component 120 and the elastic component 130, even if the fixing device 60 were to be dropped, not only the crimped portion 86 of the heat pipe 80 but also the end of the heat pipe 80 opposite the crimped portion 86 are prevented from colliding with the depth end of the accommodating groove 98. This effectively avoids the risk of damage to not only the crimped portion 86 of the heat pipe 80 but also the end opposite the crimped portion 86. Furthermore, even if the heat pipe 80 undergoes thermal expansion and deformation, the crimped portion 86 and the end of the heat pipe 80 opposite the crimped portion 86 do not directly hit the depth end of the accommodating groove 98, thereby preventing large stresses from acting on both ends of the heat pipe 80 due to thermal expansion and deformation.

[0038] Comparison form 1 FIG. 6 shows a holding structure for a heat pipe 80 used in a fixing device according to a first comparative example. In the same figure, the heat pipe 80 (80a, 80b) is held in the accommodating groove 98 of the holder 90, as in embodiment 1, but the protective part 120 and the elastic part 130 are not used, and a gap 100 remains between the crimped portion 86 of the heat pipe 80 and the end located opposite the crimped portion 86 and the deep end of the accommodating groove 98. In this embodiment, the presence of the gap 100 may prevent the crimped portion 86 of the heat pipe 80 from hitting the deep end of the receiving groove 98 with force even if the heat pipe 80 is thermally expanded and deformed. However, if the replacement fixing device is accidentally dropped during transportation, the impact force of the fall may cause the crimped portion 86 of the heat pipe 80 to hit the deep end of the accommodating groove 98 hard, raising the concern that the crimped portion 86 may be damaged.

[0039] In this embodiment, both longitudinal sides of the heat pipe 80 (80a, 80b) are accommodated in respective accommodating grooves 98, the crimped portion 86 of the heat pipe 80 is protected by an elastic protective part 120 (specifically, a compression coil spring 121), and the end of the heat pipe 80 located opposite the crimped portion 86 is elastically held by an elastic part 130 (specifically, a compression coil spring 131). However, the holding structure of the heat pipe 80 is not limited to this and may be selected as appropriate, for example, as shown in the following modified forms 1 and 2. ◎Transformation form 1 FIG. 7(a) shows a heat pipe holding structure in the first modified embodiment. In the same figure, the holding structure of the heat pipe 80 is the same as in embodiment 1, with a protective part 120 (specifically, a compression coil spring 121) having the same elasticity as in embodiment 1 interposed between the crimped portion 86 of the heat pipe 80 and the accommodating groove 98. However, unlike embodiment 1, the end of the heat pipe 80 located opposite the crimped portion 86 is positioned in contact with the deep end of the accommodating groove 98.

[0040] In this example, if the heat pipe 80 undergoes thermal expansion and deformation, the end of the heat pipe 80 opposite the crimped portion 86 is restricted in position to the depth end of the accommodating groove 98 by the biasing force of the compression coil spring 121, so only the crimped portion 86 of the heat pipe 80 is displaced toward the depth end of the accommodating groove 98. However, the displacement of the crimped portion 86 is absorbed by the compressive deformation of the compression coil spring 121, so the crimped portion 86 does not hit the depth end of the accommodating groove 98 hard. Furthermore, if the replacement fixing device is accidentally dropped, even if the impact force of the drop causes the crimped portion 86 of the heat pipe 80 to move toward the depth end of the accommodation groove 98, the movement of the crimped portion 86 is elastically absorbed by the compression coil spring 121, and the presence of the compression coil spring 121 keeps the crimped portion 86 out of contact with the depth end of the accommodation groove 98 via the space 150. Therefore, the crimped portion 86 of the heat pipe 80 does not hit the depth end of the accommodation groove 98 with force, and the risk of the crimped portion 86 being damaged is reduced.

[0041] ◎Transformation form 2 FIG. 7(b) shows a heat pipe holding structure in the first modified embodiment. In the same figure, the holding structure of the heat pipe 80 is the same as in embodiment 1, with a compression coil spring 131 as an elastic part 130 interposed between the end of the heat pipe 80 located opposite the crimped portion 86 and the depth end of the accommodating groove 98, similar to embodiment 1. However, unlike embodiment 1, a non-elastic member is used as a protective part 120 between the crimped portion 86 of the heat pipe 80 and the depth end of the accommodating groove 98. That is, in this example, protective component 120 is a cylindrical member 125 with both ends open, molded from a heat-resistant material (e.g., metal material such as SUS, SUM, or aluminum, or heat-resistant resin such as LCP, PPS, PET, PA, or PC) as a non-elastic member. This cylindrical member 125 has an inner diameter smaller than the outer diameter d1 of the normal pipe member 85 of heat pipe 80, and is designed to surround the end of heat pipe 80 on the side of crimped portion 86. Then, assuming that the axial length of cylindrical member 125 is h and the dimension of the longitudinal protrusion of the region of crimped portion 86 of heat pipe 80 where cylindrical member 125 is attached is m, the relationship h>m is satisfied.

[0042] In this example, if the heat pipe 80 is thermally expanded and deformed, the crimped portion 86 side of the heat pipe 80 is restricted in position by the heat pipe 80 side end of the cylindrical member 125 that is blocked by the depth end of the accommodating groove 98, so only the end of the heat pipe 80 located opposite the crimped portion 86 is displaced toward the depth end of the accommodating groove 98. However, the displacement of the end located opposite the crimped portion 86 is absorbed by the compressive deformation of the compression coil spring 131, so the end located opposite the crimped portion 86 does not hit the depth end of the accommodating groove 98 hard. Furthermore, if the replacement fixing device is accidentally dropped, the impact force of the drop will cause the crimped portion 86 of the heat pipe 80 to move toward the depth end of the accommodating groove 98, but the movement of the crimped portion 86 is blocked by the cylindrical member 125. At this time, the cylindrical member 125 surrounds the end of the heat pipe 80 on the crimped portion 86 side and abuts against the small diameter portion of the crimped portion 86 closer to the normal pipe member 85. However, because the end of the heat pipe 80 opposite the crimped portion 86 is elastically held by the compression coil spring 131, the force with which the cylindrical member 125 abuts against the small diameter portion of the crimped portion 86 is partially absorbed by the compressive deformation of the compression coil spring 131, thereby reducing the force with which the cylindrical member 125 abuts against the small diameter portion of the crimped portion 86, and thus reducing the risk of damage to the small diameter portion of the crimped portion 86. Furthermore, due to the presence of the cylindrical member 125, the crimped portion 86 of the heat pipe 80 is always kept out of contact with the depth end of the accommodating groove 98 via the space 150, so the crimped portion 86 of the heat pipe 80 does not hit the depth end of the accommodating groove 98 hard, and the risk of the crimped portion 86 being damaged is reduced. [Industrial Applicability]

[0043] In this embodiment, the heating device 62 is shown as an example applied to a fixing device of an image forming apparatus, but the present invention is not limited to this. In other words, the heating device of the present invention can be widely applied to heat treatment devices that require heat treatment, such as devices using other image forming methods and media drying devices that heat or dry media transported by a media transport device. [Explanation of symbols]

[0044] 1...heating device, 2...heat generating means, 2a...heat generating portion, 3...heat pipe, 3a...sealing portion, 4...holding means, 5...receiving portion, 6...protective part, 7...elastic part, 10...body to be heated, 11...pressure means, 12...object to be heated

Claims

1. a heat generating means having a heat generating portion that generates heat along the longitudinal direction and that heats the object to be heated; a heat pipe that contacts the heat generating means or the heated body and extends along the longitudinal direction of the heat generating portion; a holding means for holding the heat pipe; Equipped with The holding means includes a receiving portion for receiving the heat pipe; a protective component for keeping the end of the heat pipe on the sealing portion side and the end of the receiving portion in a non-contact state via a space;

2. 2. The heating device according to claim 1, The heating device is characterized in that the protective component is an elastic member that is elastically deformable along the longitudinal direction of the heat pipe.

3. 3. The heating device according to claim 2, The heating device is characterized in that the protective component is a compression coil spring having an inner diameter smaller than an outer diameter of the heat pipe and capable of elastically deforming along the longitudinal direction of the heat pipe.

4. 4. The heating device according to claim 3, A heating device characterized in that the protective component is a compression coil spring having a tightly closed length longer than the dimension of the longitudinal protrusion in the region of the sealed portion of the heat pipe where the protective component is attached.

5. 2. The heating device according to claim 1, The heating device is characterized in that the protective part is a non-elastic member.

6. 6. The heating device according to claim 5, A heating device characterized in that it is a cylindrical member having an inner diameter smaller than the outer diameter of the heat pipe and surrounding the end of the heat pipe on the sealed portion side.

7. 7. The heating device according to claim 6, A heating device characterized in that the protective component is a cylindrical member having an axial length longer than the dimension of the longitudinal protrusion of the sealed portion of the heat pipe in the area where the protective component is attached.

8. 2. The heating device according to claim 1, A heating device characterized in that an elastic member is interposed between the end of the receiving portion and the end of the heat pipe opposite to the sealed portion.

9. A rotating belt-shaped heated object, The heating device according to claim 1 , which is provided inside the heated object; a pressurizing means that rotates in contact with a portion of the object to be heated that faces the heat generating means, and pressurizes the object to be heat-treated.

10. a fixing means for fixing the unfixed image on the medium by applying heat and pressure to the medium on which the unfixed image is held; an image forming means for forming an unfixed image on the medium; 10. An image forming apparatus using the heat treatment device according to claim 9 as the fixing means.

Images